JUICE BOX HEAD – THE MOVIE

 NEED A SHUNT?  GOT A SHUNT THAT JUST DOESN’T SEEM TO BE WORKING?

WATCH THIS VIDEO

I got my first shunt in March 2017.  It was miserable, not because there was a problem with the shunt itself, but because I had CSF leakage around the proximal catheter under my scalp.  This absolutely wrecked the ability of the shunt to regulate my ICP.  I transitioned rapidly to unstable Intracranial HYPOtension, which I found to be as equally miserable as Intracranial Hypotension in its own special ways.

Two years.

Finally, after tests and experiments, Dr. Kenneth Liu figured out I was leaking CSF around my shunt catheter.  The technical term is “external communicating hydrocephalus”; I just called it “Juice Box Head” after the way juice leaks around the straw of those drink boxes and pouches if you squeeze them too hard.

The following video is very tongue in cheek. It’s meant to be.  I needed short, sweet, not uber-technical, which I can do all too well.  Disclaimers:  the scale of the burr hole and “catheter” (IV tubing) are larger than the actual items.  The “Bone Plaster” I used is plumber’s putty.  The “thin titanium plate” is a piece of galvanized flashing.  This video was shot in on my dining room table where I was both “surgeon” and “camera operator” (hence, the shaky sections).  That said, it is an accurate representation of how Dr. Liu solved my leak.

Why am I showing this?  Because the difference between leak and no leak was immediately noticeable, and the magnitude of improvement was nothing short of miraculous (yes, I used the “M” word).  It has made all the difference in the world for me to have a shunt that actual controls my ICP without an unwanted leak that renders the shunt all but useless.  Big Statement:  I am fairly certain it is an issue for other shunt patients, or may become an issue for those who need a shunt.  I cannot emphasize the importance of attention to this simple process, nor the risk being taken by ignoring it.  I know of whence I speak on many levels…

Without further ado, the masterpiece.  Let it load, hit the full screen icon in the lower left hand corner, & turn it up – the audio worked out supernaturally well with this bit:

THE JUICE BOX HEAD PAPERS: PART ONE

Opening Whisper:  2019 was a “rebuilding year”, as my neurological health recovered from 2 years of unstable Intracranial Hypotension.  The lack of posts on Shuntwhisperer has been due to my…invalidity.   I’ve been hammering away at this for over a month, and with the Great Coronavirus Pandemic in full swing, I am pushing this into publication, warts and all.  Please forgive any errors, sophomoric media, or broken links.  I will get around to corrections and improvements.  I believe the sentiment and subject matter make themselves obvious and cannot wait any longer…

AN OPEN LETTER TO SHUNT PATIENTS AND THE DISCIPLINE OF NEUROLOGIC SURGERY REGARDING PERITUBAL SUBGALEAL CSF LEAKAGE – AN UNDERAPPRECIATED COMPLICATION OF SHUNT SURGERY

 

INTRODUCTION TO THE PROBLEM PERITUBAL LEAKAGE

In the Shuntwhisperer post “The Hole In My Head…”, I recounted my experience with a shunt complication known as Peritubal Leakage.  Peritubal leakage (aka “Juice Box Head”, as demonstrated in this brilliantly illustrative Spielberg-esque video) is the unwanted/unregulated leakage of cerebrospinal fluid between the outer surface of the proximal shunt catheter and the dural tissues pierced by the catheter.  This results in unintended and significant drainage of CSF from the larger subarachnoid space surrounding and supporting the brain, instead of intended shunt valve-controlled drainage from the ventricular reservoir of CSF inside the brain – the distinction of these different CSF reservoirs is very important.

CSF Reservoirs
Comparison of CSF volume of ventricles accessed by ventricular shunts vs. CSF volume of subarachnoid space subject to peritubal leakage

The result: lowered/unstable ICPs with associated neurophysiologic repercussions due to CSF overdrainage from the untargeted CSF reservoir around my brain.  I endured this condition for two years before Dr. Kenneth Liu diagnosed the problem.  In March 2019, he performed a revision surgery to “plug the leak”.  The improvement I have experienced has been so dramatic by orders of magnitude that I feel the need to share it with the Shuntwhisperer community, as well as the discipline of Neurologic Surgery.

An important observation:  the size of my ventricles never changed size despite signs of Intracranial Hypotension (see below under “…Consequences Of An External Communicating Hydrocephalus”).  This led to skepticism of my condition by neurologic physicians who view changes in ventricular size on MRI exams as an indicator of shunt function.  In hindsight, stable ventricle size would be an obvious finding since the CSF overdrainage I experienced was not from the CSF reservoir inside my ventricles and through my shunt, but rather from the larger CSF reservoior of the subarachnoid space around my brain through a leaking burr-hole.  Equally important is that my adjustable shunt valve had been set to its maximum of 200mm H2O as we “chased” my decline into unstable Intracranial Hypotension during the first 4 months postop.   Ironically, this action raised my ICP, making leakage around the proximal catheter the preferential route for drainage of CSF instead of the more resistant, higher pressure route of my shunt system.

Neuroradiologists, please take note:  Hypotensive Ventricular changes only occur due to CSF pressure changes inside the ventricles; leakage from a CSF reservoir such as a leaking lumbar puncture or, as in this case, a leaking burr-hole, may not result in changes in ventricular size, making MRI evaluation of shunt function suspect if a CSF leak is present.  Re-examination of my MRI from July 2018 actually revealed changes in signal density of the cortex of my brain (parenchymal thickening) “consistent with chronic intracranial hypotension/subarachnoid hemorrhage”.

Before continuing further, I need to emphasize a very important point:

Nothing I have experienced is the result of incorrect diagnosis, improper treatment, or poor surgical technique.   It appears instead to be an unintended outcome of the current state of evolving ICPDD shunt treatment protocols.  It is my hope what follows will be taken in the spirit intended, for the benefit of patients and surgeons alike: the potentially significance of an understandably small detail in the larger picture that has more significant ramifications than currently believed.

 

PERITUBAL SUBGALEAL LEAKAGE: ONE SMALL SURGICAL DETAIL WITH SIGNIFICANT IMPLICATIONS

Peritubal Leakage is significant due to its potential to interfere with maintenance of stable ICP. Unregulated CSF release out of the cranium independent of shunt management is known to exacerbate already dysregulated neurologic function and related symptoms.

CSF_ICP_SX
“MRI Abnormalities” are dependent on the CSF reservoir affected. Leakage from extraventricular sources may not result in changes in ventricle size; chronic subarachoid leakage will cause changes in the MRI signal of the cortical (outer) layer of the brain. Graphic courtesy of Medscape.com

Peritubal Leakage itself appears to be an underappreciated/currently unrecognized potential complication of shunt placement surgery and does not appear in lists of “common” shunt complications, though symptoms associated with unstable ICP do appear; in my case, these symptoms were described as “normal”.  I now know otherwise and hope to impress upon all involved the severity of this preventable/treatable condition.  Peritubal Leakage is the result of a “perfect storm” of the wound physiology of the transdural silicone/polyurethane proximal catheter and subcutaneous shunt system components.  Researching “Peritubal Leakage” led to several articles mentioning it as a potential complication of ventricular shunts as a secondary result of distal catheter occlusion, but not as a primary complication related to delayed bone healing of the burr-hole craniotomy – mine “appears” to be the first reported case.   However, searching the term “Subgaleal CSF Leakage” results in a plethora of publications describing CSF leakage/accumulation beneath the scalp as a result of both cranial trauma and surgery.  Based on my research, observations, and personal experience, I believe Peritubal Subgaleal CSF Leakage from the subarachnoid space is a significant contributor to “common” shunt morbidities due to resulting suboptimal ICP management.  This unstable ICP  exacerbates already dysregulated neurologic  function as shown in the Medscape graphic above.  There is, however, a very bright spot: Peritubal Leakage is readily treatable, and more importantly, preventable using proven wound management techniques employing readily available materials in the neurological surgery suite.  Further, prevention of this complication is very low cost in terms of time and expense by making a simple modification to current shunt placement protocols.

PERITUBAL SUBGALEAL LEAKAGE:  THE PRECEDENT OF SUBGALEAL SHUNTS

The hallmark clinical sign of peritubal leakage I experienced was regular, periodic (over the course of several hours) visible and palpable swelling along the tract of my shunt system.  These episodes of swelling corresponded to increased relative ICP dynamics and were accompanied by tingling/itching of the scalp on the entire right side of my scalp. They persisted until ICP dynamic changed and CSF was resorbed into the tissues of the scalp.  Below are photos taken hours apart on the same day demonstrating this condition (hover cursor over photos for captions) :

The swelling  in the right photo is accumulation of CSF in the subgaleal layer of my scalp tissue originating from the burr hole where the proximal catheter of my shunt system enters my cranium..  The Subgaleal Layer is loose areolar connective tissue just above the bone of the external surface of the cranium, both binding the scalp to bone while allowing a degree of mobility of the overlying skin:

subgaleal space
Subgaleal Connective Tissue Layer and Space of the Scalp

As previously mentioned, there is scant information about Peritubal Leakage; however, much can be inferred from an accepted type of shunt employed in neonatal hydrocephalus patients known as a Subgaleal Shunt.  Subgaleal shunts relieve pathologic ICP without subjecting the neonate/infant to additional surgical stresses and growth considerations of draining CSF into the abdomen.  These shunts “simply” route a proximal catheter from an intracranial CSF reservoir into the subgaleal space before being ultimately absorbed by surrounding blood and lymphatic tissues of the scalp.  No shunt valves; tension of scalp tissues serve as the limiting factor of CSF drainage, along with direct taps of the shunt reservoir as needed.

Distention of the scalp due to CSF forced out of intracranial spaces under ICP can be significant but are normal in this type of shunt system used in newborn infants.   However, for an adult patient with a VP shuntperiodic swelling along the shunt system tract constitutes a red flag of uncontrolled CSF leakage into the subgaleal space.  Swellings that persist for more than a day may be a sign of a subgaleal hematoma, a collection of blood beneath the scalp that could indicate bleeding inside the cranium which requires immediate medical attention.

 

PERITUBAL LEAKAGE: CAUSALITY

Peritubal Leakage is the predictable result of shunt treatment based on the physiology of the surgical wound created in the cranium for introduction of the proximal catheter of ventriculoperitoneal/ventriculoatrial shunts.  This may also apply to lumbar shunts as well; however, I will restrict this post to VP/VA shunts and my understanding of currently accepted surgical procedures, very briefly summarized here:

  • Scalp flap incision and reflection:
  • Burr-hole/craniotomy: a surgically created bone wound performed for the purpose of exposing the dural lining of the brain to allow insertion of the proximal shunt catheter into a ventricular CSF reservoir inside the brain.  Creation of  the burr-hole must be performed with care to prevent pushing bone fragments into the cranium and/or tearing the dural tissue immediately beneath (Having performed many surgeries in nasal sinuses, I know from experience, this is delicate.  Think of removing the shell from a boiled egg without tearing the inner collagen membrane, a membrane that varies in consistency from tissue paper leather amongst various patients).  The diameter of the burr hole is approximately 15mm/0.6in.  (The average thickness of the adult human cranium is about 6.4mm/.25in; thus, the resulting bone wound in the cranium is ~2.5 wider than it is deep.  This is important in determining how the bone wound will heal without intervention as will be explained shortly.)
  • Placement of the proximal catheter through the dura, across the subdural space (containing CSF) around the brain, through the frontal lobe of the brain, targeting the Foramen of Monro at the base of the third ventricle inside of the brain. This is accomplished via real-time 3D guidance via Medtronic’s brilliant Stealth System, shown in this video:
  • The distal catheter is routed to its terminus equally brilliantly via subcutaneous tunneling, shunt valve(s) are connected with catheters, and the system checked for integrity, all very delicate tasks that require attention and time.
  • The scalp flap is repositioned and secured with sutures/staples.

 

THE BURR-HOLE PROBLEM

This bone wound in the cranium is a small but very, very significant in terms of its size, shape, and presence/composition of the proximal catheter:

1317_CFS_Circulation(1)
Intact cranium
Dural Bulge at Burr-hole
Removal of cranial bone results in lack of support of dura; CSF under ICP bulges dura outward
1317_CFS_Circulation(1) proximal catheter
Subarachnoid CSF Leakage
Unhealed Craniotomy
MRI demonstrating my CSF leak

 

 

Early wound physiology begins to demonstrate a potential problem with the transdural proximal catheter.  Shunt catheters are 4.0mm in diameter with 1.5mm inner lumen for CSF drainage.  They are made from a very flexible silicone or electrospun polyurethane-based material which are treated to prevent adhesion of clumps of cells to the inside of the catheter.  These adhesions can potentially obstruct the catheter resulting in shunt system failure.  The anti-adhesion quality of these components also prevents cells from adhering to its outer surface.  This means that neither collagen based dural tissue nor cranial bone adheres to the proximal catheter during healing. Examination of the transdural proximal catheter reveals that the collar of dural tissue around the catheter is no longer supported by bone;  as such, it cannot resist the outward pressure of CSF caused by ICP (Monro-Kellie Violation).   As a consequence, cerebrospinal fluid in the subdural space under sufficient intracranial pressure can displace the unsupported edges of the dural wound outward like an organic juice-box valve, allowing CSF to escape from the subdural reservoir and accumulate along the tract of the shunt system.  The visual analogy I prefer is how juice escapes around the straw of a juice box/pouch when squeezed, hence the moniker “Juice Box Head” to describe Peritubal Leakage.

Mathematical analysis of this condition reveals that the area perimeter of the 4mm catheter is an order of magnitude larger in potential volume than its 1.5mm inner lumen.  The inner lumen of the proximal catheter has a fixed cross sectional area of 1.76mm2. The same catheter’s 4.0mm outer diameter surface area is 12.56mm2.  if the dural edge is displaced by CSF under the influence of ICP by 0.5mm, the total area for potential leakage around the periphery of the catheter nearly matches the internal lumen area where CSF drainage is intended to occur under the control of the shunt valve.  If the dural tissues yield at ICPs lower than the opening pressure of the shunt valve, CSF will preferentially leak around the proximal catheter from the subdural CSF reservoir instead of the intended ventricular reservoir.  This process is the basis for the development of unstable ICP as well as transition from Intracranial Hypertension to Intracranial Hypotension as I discovered.

Current standard neurologic surgery protocols focus on the demanding tasks of opening the patient’s cranium, placement of the shunt catheter through the brain into the desired ventricular CSF reservoir, and routing of the distal catheter to drain CSF into the desired body cavity.  There is no standard protocol to address the small but very significant bone wound created by the craniotomy – it is left to “heal on its own”, an oversight which I contend is in contravention to known wound physiology.  Bone defects heals very slowly, at a rate of 100-200 microns (um) per day.  New bone grows from the blood supply of existing living trabecular bone; thus, the circular craniotomy heals from the edges towards the center (seen in the video of serial CT/MRI scans of my craniotomy).  Using these facts, it can be seen that it would take this 15mm/15000um wound between 10 and 20 weeks to heal with bone.   The discipline of Orthopedics tells us that the time required for a bone wound to heal to 70% density is 16 weeks (Human Bone Sigma Healing).

However, bone is not the only tissue actively growing in a healing wound: soft tissue (proliferative collagen, aka “scar tissue”) can – and does- preferentially invade the volume of a wound previously occupied by bone at a rate of 1000-2500um (1-2mm) per day, 10 times faster than the slower growing bone (osteoid  tissue, which begins as a soft tissue that later becomes infused with calcium in a form known as hydroxylapatite.  Once non-bony soft tissue organizes in a wound, bone formation is precluded from that volume of the wound.  In the case of our circular craniotomy, this is aggravated by the invagination of the scalp flap into the craniotomy, creating a dimple into the wound volume which was occupied by cranial bone pre-surgically.  Further aggravating this undesirable condition are the dimensions of the burr-hole, or rather the ratio of its diameter to the thickness of the cranium: at ~2.5 times as wide as it is deep, even this small wound becomes subject to immutable laws of bone healing.  Its shallow, wide shape predisposes it to soft tissue invasion as well as invagination of the scalp tissue into a volume once occupied by bone.

The result is a transdural silicone catheter surrounded, at least in the early weeks of healing, by “loosely organized” dural collagen and soft/scar tissue.  There is no actual “seal” of dural tissues to the outside of the catheter because cells cannot adhere to the silicone/polyurethane catheter.  The integrity of the bony cranium is compromised by the craniotomy, and as I discovered, can lead to significant morbidity if intracranial pressures are sufficient to cause CSF to seep between the outside of the catheter and attached shunt system components.  This chain of surgically implanted shunt components creates a potential reservoir in the subperiosteal/subgaleal space, allowing CSF seeping around the proximal catheter to accumulate around the shunt system  outside of the cranium creating the aforementioned subgaleal hygroma.  Below is a a video of images and models taken from serial CT/MRI scans taken at postop, 3 months+++++++demonstrating this exact series of circumstances that caused my unstable shunt treatment: a transdural catheter, lack of bone to support the dural tissues at the outer perimeter of the catheter, and the late bone healing pattern of the burr-hole craniotomy

 

PERITUBAL LEAKAGE: CONSEQUENCES OF AN EXTERNAL COMMUNICATING HYDROCEPHALUS

Peritubal Leakage caused me to transition from Intracranial Hypertension (intolerance of upper limits of my ICP physiology) to unstable Intracranial Hypotension.  Having experienced both ends of this spectrum, I can say each has its own unique “misery index”.  I can further testify as to how unstable Intracranial Hypotension limits functional capacity by orders of magnitude.  Here is a brief summary of the most severe symptoms I experienced:

  • Subgaleal Hygroma: Regular periodic swelling, both palpable and visible, along shunt tract beneath scalp with accompanying increases in barometric pressure AND/OR systemic blood pressure/heart rate dynamics. These episodes of swelling were accompanied by soreness and tingling of my scalp three to four inches around my shunt components, with occasional crepitus (crackling sensation of skin when touched due to fluid accumulation).
  • MRI/CT evidence of transition to Intracranial HYPOtension: these findings are NOT restricted to changes in ventricular size, and instead may be evidenced by changes in the signal of the outer cortex of the brain.  Shunt settings and individual patient physiologies may show different combinations of these findings, and subjective patient symptoms MUST be given credence when they seemingly conflict with objective test results.
  • Severe Intolerance to barometric pressure changes related to weather.***
  • Intolerance to prolonged (24-36h) of barometric pressure below 950 mb, with accompanying symptoms:
    1. Extreme fatigue, frequently requiring bed “rest”
    2. Increased fibromyalgia pain
    3. Cognitive challenges including impaired problem solving, depressed mood/labile emotions
    4. Aggravated level of tinnitus during periods of perceived low ICP, compared to pulsatile tinnitus during periods of perceived high ICP.
    5. Changes in vision out of right eye (my “migraine side”) from day to day manifesting as changes in near vision accommodation
    6. Over the course of two years, the development of apparent autonomic and neuroendocrine dysfunction manifesting as the Hyperadrenergic form of POTS as well as exercise intolerance/muscle wasting presumably related to HPA axis dysfunction (I show evidence of Empty/Partial Empty Sella Syndrome which developed only after the onset of Intracranial Hypertension).

This list is short and does not delve into further subcategories at this time, some of which are very significant.  As noted in the title, this is “Part One”.

 

THE SIMPLE SOLUTION TO PERITUBAL LEAKAGE: GUIDED TISSUE REGENERATION

Guided Tissue Regeneration (GTR) is a surgical process originating in Orthopedics research in 1959:

  • Hurley LA, Stinchfield FE, Bassett AL, Lyon WH (October 1959). “The role of soft tissues in osteogenesis. An experimental study of canine spine fusions”. The Journal of Bone and Joint Surgery. American Volume. 41-A: 1243–54. PMID13852565.

GTR is used extensively in orthopedics, oral surgery, and  neurologic surgery to exclude soft tissue from a bone wound, as well as enhance bone volumes in areas so desired.   In my dental practice, I personally employed GTR as part of oral surgical procedures to ensure adequate bone volume and quality in the desired location of dental implants, as well as to regrow bone lost due to disease, pathology, or trauma.  GTR is beginning to become a topic of discussion in neurologic surgery as well, and after my experience, I can say it cannot come fast enough.

GTR facilitates desired bone growth by a twofold approach.   First, a biocompatible/bioactive grafting material is placed into a bone wound.  The grafting material “holds space” into which new bone to heals after graft material is resorbed during normal healing, ultimately being replaced with the patient’s own bone.  In some cases, vital bone is grafted from one part of the patient’s body to the desired site, but the healing process is still the same, even with vascularized grafts.  Calcium sulfate, essentially medical grade bioenhanced plaster, is a popular, effective, and inexpensive option for this size defect.  Newer materials are becoming widely accepted that may prove even more effective and will be the topic of another post in this series.

The second part of GTR is a “bone bandage”: a biocompatible membrane placed over the graft site (in this case, the burr-hole craniotomy) which excludes unwanted soft tissue from the bone wound.  This “bone bandage” is known as a guided tissue membraneGuided tissue membranes need to be biocompatible and must persist in the surgical wound long enough for osteoid tissue to form, preferably a minimum of 8 weeks.  These membranes are made from various materials; a very short list includes PTFE (aka “Teflon”), cross linked bovine collagen, and titanium in the form of foil and thin plates.  Some membranes such as those made from collagen are dissolved by the body over time; others such as Teflon and titanium persist.  Each has its unique pros and cons depending on the application, and in this particular application, I personally see titanium plates as the clear choice: the combination of calcium sulfate and titanium offer immediate dural support from postop through burr-hole healing with bone. Examples of these readily available materials in a neurologic surgery suite are shown below:

 

In the revision surgery which has literally given me my life back, Dr. Kenneth Liu revised my original shunt with the goal of sealing the unhealed and leaking burr-hole.  This was performed March 2019, almost exactly 2 years to the day Dr. Liu had placed my original shunt.  He removed/debrided the soft tissue that had formed in my burr-hole (preventing bone healing) and created bleeding points at the periphery with the surgical equivalent of a Dremel tool (remember: new bone grows from the blood supply of existing bone).   A groove was created in the edge of the craniotomy for the proximal catheter to lie in. The burr-hole defect filled the resulting wound with bioactive calcium sulfate (bone “plaster”) and covered the craniotomy with a readily available stock round titanium bone plate that, when screwed into place, extended beyond the edges of the craniotomy.

Dr. Liu also replaced my Sophysa Polaris shunt valve with a Meithke ProGav 2.0 valve, not because the Sophysa was suspected of being defective (Sophysa has an outstanding record of reliability), but because the newly available Meithke ProGav offered a greater degree of opening pressure adjustability, not to mention being much a much smaller size.   Dr. Liu’s Facebook page has this picture of what may be my actual valve, giving an idea of its size, the approximate equivalent about of three quarters stacked atop one another:

My ProGav
(My?) ProGav 2.0 Shunt Valve from Dr. Liu’s FB page

This valve is adjustable in “infinite” increments over its 0-200mm H2O pressure rating using external magnetic tools, is MRI resistant to 3T (I can vouch for both the Pro-Gav and Sophya valve’s resistance to MRI fields).  Further, the Pro-Gav’s low profile has significantly improved comfort as well as not being as visibly apprarent with my “high and tight” hair…style.

From the first moment I remember postoperatively after revision surgery, I could feel enormous improvement.  The best description I can offer is that I actually had a “normal” pressure in my head, as opposed to an “empty” sensation.  This has only improved in the last year.  Some of the improvements I notice are:

  • Barometric pressure sensitivity: prior to the revision, I was a puppet to the weather as well as altitude.   This problem was so severe that I could not live at my home located at a modest 2200 feet above sea level, nor could I tolerate barometric absolute pressures (station pressures***) below 950mb.  I was a geographic hostage, a medical gypsy forced to relocate to lower elevations/higher barometric pressure areas almost weekly for relief.  Low barometric pressures due to weather or altitude would cause me to experience extreme fatigue.  As mentioned in “The Hole In My Head…”, I consulted with Dr. Liu to procure a home hyperbaric chamber to prove to myself and to Dr. Liu that my extreme sensitivity to normally tolerable environmental changes was real.  Post-revision, I have been from sea level to as high as 4000+ feet without any noticeable deleterious effects.   At the time of this post, the current station pressure is 918mb, and aside from a predictable mild morning migraine, I’m functional, whereas prior to the revision, I would be confined to bed and very lethargic.
  • Immediate 99% reduction in Peritubal Leakage: my craniotomy is by now healed with my own bone beneath the titanium plate.  This bone does not adhere to the proximal catheter,  but it does provide enough added resistance to dural displacement and unwanted CSF leakage around the catheter that 99% of the time I cannot appreciate any CSF accumulation as evidenced by tactile/visual swelling along the shunt system.  I no longer experience any swelling along the shunt components,  which now feel as if my scalp has “vacuum formed” over them. Occasionally there is a very, very small accumulation of CSF along the catheter at the edge of the plate, but it is not visibly evident, only noticeable by telltale slight tingling of the adjacent inch or so of scalp – greatly reduced from pre-revision conditions.  Best of all I do not have the symptoms of Intracranial Hypotension that previously accompanied the degree of peritubal leakage previously demonstrated.
  • Slow but steady improvement in neurologic functions:
    1. Exercise intolerance: pre-revision, I was pathologically intolerant of any degree of exercise and was becoming severely deconditioned.  Stairs were becoming a problem.  Now, I tolerate reasonable amounts of physical activity and light exercise with normal recovery as opposed to the week of intolerable pain that previously resulted from any exertion.
    2. Pain Level: 90% improved, and not a moment too soon.  Fibromyalgia pain is linked to Intracranial Hypertension. I can say with absolute certainty that Intracranial Hypotension made my fibro pain as bad, if not worse, than Intracranial Hypertension.  Let me be clear, both were severe and varied only by levels of misery.
    3. Functional Capacity: I was essentially a low-functioning invalid pre-revision.    I am now able to live independently in a manner consistent with a 59 year-old male with an Intracranial Pressure Dysregulation Disorder.  I enjoy several hours of function a day, whereas pre-revision, I would be bedridden for 3-4 days at a time for every “good” day I had out of bed.  I’m somewhat ashamed to say that the lack of posting on Shuntwhisperer has partly been because I’ve been actually able to get out and have a life.
    4. Improved Cognitive Function: Goodbye, Brain Fog, memory lapses, and the inability to perform simple math in my head.
    5. Improved sleep – prior to revision, sleep had become increasingly poor, with frequent episodes of waking at night with my heart pounding out of my chest for no apparent reason. I believe I was experiencing episodes of breathing patterns similar to Cheyne-Stokes due to aggravation of low ICP at night.  I required CPAP and supplemental oxygen, but no longer need them.  Mornings no longer involve an hour of misery/agony that persisted until I consumed enough caffeine to raise my ICP; these episodes would stop at about the same time I could detect flow in my shunt system.  (note: shunt-assist related nocturnal overdrainage will be covered in a separate post)
    6. Improved emotional health: though I had learned to cope with the ups and downs that seemed to accompany swings in ICP, it was exhausting. This too has improved by orders of magnitude, and I rarely find myself forced to evaluate  seemingly irrational emotional states for validity.

 

DISCUSSION

First of all, my heartfelt gratitude to Dr. Kenneth Liu, most recently practicing at Penn State/Hershey Neurologic Services, for his support and willingness to make this improvement possible.  Dr. Liu, sincere thanks.

It took nearly 18 months to deduce that I was experiencing Peritubal Leakage, another 6 months before it was able to be corrected.  I will summarize the experience in technical terms: pure, absolute hell.  The condition I was experiencing was an uncontrolled CSF leak via an unintentional, surgically created, external communicating hydrocephalus.  Reviewing how this leak likely occurs: the dural wound around the proximal catheter lacks the rigid support of the cranial bone removed during shunt placement surgery.  ICPs exceeding the ability of elastic dural tissues to seal against (not “to”) the proximal catheter allowed CSF to seep out from the subarachnoid space, around the outside of the catheter between the catheter wall and edges of the dura.   The leaked CSF pooled along and around the components of the shunt system (catheters, shunt valve, shunt assist valve), resulting in noticeable periodic swelling of the scalp as shown in photos/video.  At the time, the opening pressure of my system was 200 to 450mm H20*.   In my case, it is likely that peritubal leakage occurred at ICPs below the opening pressure of the shunt, creating an “overdrainage” scenario similar to a shunt system set at too low of an opening pressure.  However, CSF leakage likely occurred from the undesired subarachnoid reservoir of CSF around the brain.  This is a much larger CSF reservoir than the intended third/lateral ventricles and thus not as self-limiting nor regulated by the shunt valve(s).  The volume of CSF in the subarachnoid space directly affects brain buoyancy as well as neurologic function.  I exhibit borderline Chiari 1 imaging when lying flat; a reduction in brain buoyancy would theoretically aggravate impingement of my foramen magnum by my cerebellar tonsils.  Further evidence supporting this theory is that while I exhibited symptoms of Intracranial Hypotension, the size of my ventricles remained stable over 2 years, indicating the shunt system was not responsible for the “overdrainage” because unwanted CSF loss was not coming from the ventricular reservoir, but rather the larger subdural reservoir.

As mentioned previously, I have experienced improvement in neurologic and emotional health that are literally orders of magnitude better than when I was experiencing PT.  Some of those improvements happened immediately; some of them have taken months.  Dr. Liu had a term: “Angry Brain Syndrome”, describing dysfunctional neurologic health caused by pathologic ICP dynamics.  The term has proven to be very apt.  And, while I endured significant difficulty for two years, I am now enjoying dramatic and continuing improvement as a result.

 

NEUROLOGIC SURGERY: A PROPOSAL TO MAKE A SIMPLE IMPROVEMENT

Pointed Statement Alert: by now I’m certain I’m not the only one who has or will experience negative impact on already impaired neurologic health due to Peritubal Leakage.  I’ll stop short of saying  peritubal leakage is nearly universal, but current shunt surgery protocols as described make it potentially possible in every patient if the burr hole craniotomy is not addressed with Guided Tissue Regeneration.   I have spoken with two neurosurgeons about the following proposal and have been greeted with “we don’t see peritubal leakage as a problem”.  Respectfully, as the surgeon and not the patient, that statement carries little validity when viewed in the dichotomy of subjective findings and objective experience, especially when based on known wound physiology as I have described.  The impact on patient function of this issue is inarguably quite significant, thus I recommend that the belief that Peritubal Leakage is “not seen as a problem” needs to be revisited.

Based on my surgical training and experience, knowledge of bone wound physiology,  not to mention my “experienced based residency” as a shunt patient, I can say with absolute certainty  that peritubal leakage potential carries a significant negative impact on the stability of intracranial pressure dynamics, and by extension, neurologic health.  My condition was ultimately and dramatically improved by a second surgical intervention and the employment of a well-understood wound care process known as Guided Tissue Regeneration.  The magnitude of that improvement has been literally the difference between having a modicum of function vs. being bedridden and essentially nonfunctional every time the weather changed or I just went to my home at the “dizzying” altitude of 2200 feet.  As such, I propose that Guided Tissue Regeneration repair of burr-hole craniotomies be considered a standard practice in VP/VA shunt surgery at initial placement using bioactive calcium sulfate and titanium plating.  I further propose that patients exhibiting signs of subgaleal hygroma be evaluated for peritubal leakage through CT/MRI imaging of bone healing of the burr-hole craniotomy, signs and symptoms of Intracranial Hypotension, with due consideration given to GTR revision/valve revision in cases of poor/delayed bone healing of the initial burr-hole craniotomy.

The addition of this extra measure necessarily requires an evaluation of the cost, time, and risk/benefits of a GTR repair of a craniotomy, and from every standpoint, pros outweigh cons in every category.  First, flap design needs to consider adequate wound margin from the titanium plate covering the craniotomy.  Next, materials: standard armamentarium of the neurologic surgical suite reveals that integral materials and components, chiefly bioactive calcium sulfate (with metronidazole/rifampin added)** and “stock” circular thin screw retained solid (not mesh) titanium bone plates, similar to those shown above. Surgical time is estimated to be 15-20 minutes at most during initial implementation to create a groove at the distal edge of the burr-hole for the proximal catheter to lie in,  preventing its impingement by the edge of the bone plate, followed by placement of the calcium sulfate, and fixation of the bone plate, preferably before final set of the calcium sulfate graft**.  At this point, repositioning and closure of the flap would proceed as normal.  Scalp invagination and soft tissue migration into the burr-hole/craniotomy would be effectively precluded.  The patient’s healing physiology will dissolve the calcium sulfate and replace it with their own bone over 4-6 months.  Cost of the bone plate and calcium sulfate, while not inexpensive, are comparative pennies (less than $1000 billable) compared to the cost of shunt placement surgery ($75,000+ for the my first shunt, $28,000 for the revision).  I would go so far as to consider billing these items at cost due to the critical nature of their role in enhancing wound healing and mitigating unpredictable leakage and suboptimal patient experiences as a result; in reality, “billing at cost” is becoming an unfortunate standard not only in Medicare/Medicaid, but private insurance plans as well.  But, losses here can be made up on volume (sad but true medical humor).  The true cost savings of adding Guided Tissue Regeneration to shunt placement surgery is the incalculable cost of improved treatment outcomes and reduction in monetary and risk costs of revision surgeries to correct the previously unrecognized consequences of Peritubal Leakage.

There is no apparent predictor for the incidence and degree that peritubal leakage will occur in a shunt craniotomy, but known wound physiology supports its likelihood.   Improving the seal around the transdural proximal catheter by ensuring ideal bone regrowth with Guided Tissue Regeneration at the time of shunt placement makes good surgical sense and is ultimately in the best interest of patient and surgeon alike.   Guided Tissue Regeneration is a refined field that extends back 35 years; the process I have described of using bioactive calcium sulfate and a non-porous titanium plating is a GTR process that has stood the test of time.  Therefore, I propose that Guided Tissue Regeneration be considered a standard practice in VP/VA shunt surgery at the initial surgery.

**Check back for an upcoming post: “Platelet Rich Fibrin: beyond Calcium Sulfate” 

 

 

NEUROENDOCRINE THEORY FROM AN ENDOCRINOLOGIST – AN EXPERT SPEAKS

Three particular informational sources have played a key role in making sense of disparate symptoms:

  1. The Driscoll Theory by Dr. Diana Driscoll.  Although primarily focused on Ehlers-Danlos/POTS patients and the particular Intracranial Pressure Dysregulatory Disorder these patients often experience – Intracranial Hypotension – especially her observations about the carotid triangle, vagus tone, and cerebrospinal pooling/blockage due to “brain sag”.
  2. Adrenal Fatigue Syndrome by endocrinologist Dr. Michael Lam, MD and Dorine Lam, RD, MS, MPH.  A well written book describing endocrine system interactions as a result of long term, high level stress, how that system begins to become dysregulated, and the hormonal consequences thereof, as well as approaches in dealing them.
  3. Multiple Research Papers that have documented the presence of hormonal receptors in the cells that produce CSF.  In a word, many of these hormones become dysregulated in Adrenal Fatigue/Failure.  Each in its unique way contributes to increases in blood pressure, CSF production – or, as in the case of aldosterone – is responsible for both.  This means increased blood pressure & therefore increased Cerebrovascular Dynamics as well as increased CSF production.  The perfect storm for development of elevated ICP, and if not controlled, an ICPDD in patients with predisposing factors.  Some receptors are estrogen/progesterone sensitive, possibly explaining why patients are more commonly female.   Further,  looking back to Dr. Lam and Dorine Lam’s body of work, it will be interesting to compare the upswing in ICPDD diagnosis with the increase in estrogen-like compounds in everything from food supply to dental fillings.

All these fell in my lap within a two week period in December 2018 while I was hunkeringS down waiting for a shunt revision, and to my surprise, they did not lead me to what I was looking for: why I developed IIH.

Well, sort of.

They actually led me to a conclusion that I cannot emphasize enough, hence the big letters here:

“The Secondary Acquired Adult Onset form of the “disorder” known as IIH is actually a complex symptom of a dysregulated endocrine system, including “Adrenal Fatigue”, which is most commonly caused by chronic stress.  Therefore, I name CHRONIC STRESS to be the main cause of altered/elevated ICP and the onset of ICPDDs, and the ultimate reason I developed an ICPDD.”

Shuntwhisperer’s Neuroendocrine Theory of IIH, Dec 2108

But wait, there’s more:

“Successful treatment of ICPDDs must necessarily involve endocrine function AND CAPACITY* before any ICPDD can be successfully treated.  To treat only the ICPDD is treating only the symptom; without lifestyle/dietary changes and endocrine support can possibly condemn a patient to unnecessary prolongation of their ICPDD.”

Shuntwhisperer Neuroendocrine Theory of IIH Corollary #1 Jan 2019

And just when you didn’t think it could not get ANY better:

“Elevated ICPs cause deformation and damage to key portions of the brain controlling the endocrine regulation, especially the HPA Axis.  The HPA axis must be well regulated to maintain ICP equilibrium.  THEREFORE: TREATMENT OF ICPDDS WITHOUT TREATMENT OF ASSOCIATED ENDOCRINE DYSREGULATION WILL BE SUBOPTIMAL.”

Shuntwhisperer’s Neuroendocrine Theory of IIH Corollary #2 Jan 2019

In other words, endocrine dysregulation that leads to an ICPDD, left untreated, can cause the ICPDD to persist, and more corollaries are coming.

But don’t take my word for it.

Take an expert’s.  I swear, I did not rip this off, but Dr. Lam’s book led me to the same conclusion:

NeuroEndoMetabolic Component Dominance: Stages of Stress

Been a long hot summer day.  I miss Trina.  Leaving you to it.

The ShuntWhisperer

July 11, 2019

 

Stressed-Out-1024x614

 

 

 

 

SHUNTWHISPERER 2.0 – NEW PERSPECTIVES, NEW THEORIES, BETTER OUTCOMES AND QUALITY OF LIFE

“…My last post was in late 2018 regarding an epiphany I had been given regarding a theory about how a person develops acquired adult IIH. Of course, right at that point, the creaking, weak, bottom fell out from under me.

Again….”

Note:  I need to acknowledge something to a person who reached out to me for help.  This person believed they were developing an infection of their shunt and were desperate.  Due to my own recent challenges, I didn’t open that email until a week later, and then due to some strange glitch, lost it entirely.  To that person, I am deeply sorry, and I pray you were able to avail yourself of the ER in time.  FWIW, I just went through the same problem 7 weeks post-revision.  I post my email contact, ShuntWhisperer@ShuntWhisperer.com to help answer questions if possible, but I am not a neurologist or neurosurgeon, and if anyone should find themselves in and emergency situation (infection of the shunt tract qualifies), get to your physician or ER first, then email me if you like.  FWIW, I am making it a point to check my email every morning at the very least as long as I am able.

 

Greetings to all. 

It’s been a minute, to be sure…more like 4 months.

My last post was in late 2018 regarding an epiphany I had been given regarding a theory about how a person develops acquired adult IIH.  Of course, right at that point, the creaking, weak, bottom fell out from under me.

Again. 

I had to devote what little functional capacity I had to managing this new challenge; making new posts here was just not possible.  February was a very, very, very (etc.) difficult month.  Most days I felt like I a lone person in a dark void above a bottomless abyss, clinging by my fingernails to my spiritual, almost tangible touchstone, Jesus Christ.  I can say with complete certainty He is the only reason I am still here to right this story.

The Lord works in His own way(s).  In my case, Dr. Kenneth Liu of Penn State Neurological Services, the neurosurgeon who saved my life by placing my first VP Shunt two years ago, revised my shunt and repaired the inexplicably persistent hole/CSF leak associated with the craniotomy (surgically created hole in my head).  I referenced this problem in the post “Juice Boxes and My Brain…Who Knew?). I can now say with a weird sense of satisfaction that I now have a metal plate in my head.  A small one, but nonetheless, a metal plate.

Cool.

This surgery resulted in an immediate, marked improvement, but still with instability, though not nearly as severe.  There was still a small but noticeable  CSF leak.  At 5 weeks that last leak suddenly stopped, and it was as if my brain had suddenly been switched back “ON”.  Most notable was that extreme sensitivity to certain triggers, especially barometric pressure, was either drastically reduced or eliminated altogether.   Before the revision surgery, I could not stay at my new retreat in the mountains at a modest 2200’ elevation if the barometer dropped below 940 mb.  I would become bedridden with fatigue, pain, and ‘brain fog’.  I would be forced to leave the mountain for lower elevations, and I began to be able to predict at which turn in the road I would start to feel improvement.  I would stay at a lower altitude for a week, and when I felt better, I returned, only to have the scenario play out over again within the next 7-10 days.  Was this real, or was it some perverse trick of my psyche?  I decided to find out, and with a prescription from Dr. Liu, I bought a home hyperbaric chamber.  Expensive, but it was the only way I knew to answer the question about the effect of barometric pressure on my personal form of this disorder.

I’ll go into more detail about the chamber later; for now I’ll just say I ran a series of controlled experiments.  The results were undeniable: climbing in the hyperbaric chamber and simply increasing the pressure inside to 30mb above local pressure reduced or eliminated by pain and feelings of fatigue.  However, no matter how long I stayed in the chamber, once I exited, those symptoms returned in 1-6 hours depending on local conditions, so there was no doubt that this small change in barometric pressure was enough to drastically affect my well being.

I also noticed something else: when I got out of the chamber, I could feel my shunt flowing.  If you have a shunt, you know what I mean.  More importantly, I noticed that swelling developed along the shunt components under my scalp starting at the craniotomy and eventually proceeding back to behind my ear.   I interpreted this as a CSF leak.  The catheter that connects to the shunt valve is a surgical silicone; human tissue does not adhere to this material.  I also discovered these catheters are further treated make them even more resistant to the adhesion of cells in order to prevent stray bits of protein and brain tissue from adhering to the inside of the catheter and eventually blocking it; this treatment is intended to prolong the life of the shunt.  In my case, bone had failed to fill back in the craniotomy, leaving a path for CSF to leak between the outside of the catheter and the dura and along the catheter and shunt under my scalp.  This resulted in overdrainage of CSF as it was drained not only from inside my brain as intended, but from outside the brain as well.  This caused me to experience intracranial hypotension, and was a truly miserable test of my personal belief that a more appropriate term for this disorder is Intracranial Pressure Dsyregulatory Disorder (ICPDD). 

I took this information to Dr. Liu and ultimately the decision was made to revise the shunt and repair the craniotomy.  Now that this unwanted leak has been stopped I have experienced increasingly stable improvement of my disorder, including greater functional capacity and dramatically reduced ‘fibro’ pain.  I still have challenges from the effects of almost 2 years of wild swings in my ICP, including physical deconditioning.  Spring weather patterns here have been brutal, with at least 4 “bomb-grade” storms (defined as a weather system with at least a 24 mb drop in barometric pressure in 24 hours) in the last month.  Prior to the March surgery, these systems invariably laid me up for at least three days; now, their effects on my disorder are greatly diminished, and seem to be continuing to diminish with each passing day.  Only one recent freak set of back-to-back storms really hit me hard, but in that case there was also a potentially serious late postop complication that I was fortunate to recognize and address before it got out of control.

All this preamble brings us to now.  ShuntWhisperer started as merely a “this is my story, maybe it will help you” type of blog.  Over the course of two years, I’ve learned more as I’ve continued research and experienced new challenges that while very difficult, contributed to a better understanding of my disorder.  The structure of the original site was never intended to present this material of this depth in a coherent and orderly manner.  I never expected it to be more than a few pages, but it has blossomed well beyond that.  Thus I will be  restructuring the site “on the run” as ShuntWhisperer 2.0.  It is intended to be concise, presented in lay language to the degree possible, and accompanied by references to existing research, with a reference section for physicians.  Please don’t expect a visually dazzling site; I simply don’t have the time to post anything but pertinent information.   Also, the original ShuntWhisperer site and its contents will still be available, accessible from the new landing page.

SW 2.0 is still intended to be based on my personal experiences and research.  I can’t claim anything I post applies to any other person with a disorder of altered intracranial pressure, although there are certain immutable laws of human physiology that lead me to suspect that is indeed the case; I just can’t make that claim.  I’m not sponsored, I don’t get paid for this, and don’t care to receive any credit for any good that comes of what I post.  I am doing this in Service to God in an attempt to help others, as well as in memory of my wife Trina.  My contact email is Shuntwhisperer@shuntwhisperer.com for anyone who has a question, feedback, or suggestion. 

As always, prayers to all for comfort, support, and a better quality of life.

 

Wes

The ShuntWhisperer

April 26, 2019

 

Today’s storm and rain has passed; it’s a gorgeous spring day on the mountain, and I’m going to take a break to enjoy it, wishing Trina was with me.

“But ask the animals, and they will teach you, or the birds in the sky, and they will tell you; or speak to the earth, and it will teach you, or let the fish in the sea inform you.  Which of all these does not know that the handoff the Lord has done this?” 

           Job 12: 7-9

 

How Intracranial Pressure Becomes Elevated: Part 2, Short and Sweet

Intracranial Hypertension is the elevation of pressure  of fluids and tissue inside the fixed volume of the rigid intact skull.   This elevation of pressure has two basic mechanisms*:

  • Cerebrospinal Fluid Dynamic Imbalance: A net accumulation of of Cerebrospinal Fluid (CSF).
  • Cerebrovascular Dynamic Imbalance: A net accumulation of blood in the brain caused when veins are not capable of draining the volume of blood pumped into the brain by the heart (Monro-Kellie 2.0, Dr. Mark Wilson, Royal College of London, 2016)

*soft tissue tumors can also occupy space inside the skull and potentially raise ICP but are considered a separate causative mechanism from those that are considered in ICPDDs

The cause of these imbalances can be either genetic/developmental (primary) or related to trauma (secondary).  They are closely interlinked and may both be present to a certain degree.

One example of CSF Imbalance would be non-communicating hydrocephalus.  CSF is produced from arterial blood in small hollow areas of the brain called ventricles.  Ventricles are normally interconnected with one another and the space around the brain.   CSF circulates through these areas passively due to the pulsation of blood vessels and also likely movement of the body.  If one or more of these ventricles does not communicate with the rest of the system, the CSF it produces accumulates and displaces the brain outward.

Another exmaple of CSF Imbalance illustrates the interrelationship between CSF and Blood dynamics:  obstructed veins may not absorb enough CSF out of the skull to prevent a net accumulation of CSF, as well as leading to this example of:

Cerebrovascular Dynamic Imbalance: would be Chronic Cerebrovascular Venous Insufficiency, or CCVVI.  In simple terms, damage or constriction (stenosis) of one or more of the veins that drains blood from the brain compromises the ability of blood to leave the brain.  At a certain critical level of blood flow and pressure, blood begins to accumulate in the brain as it is pumped through arteries at a greater volume than it can drain.  This accumulation of blood causes the thin-walled veins to swell, which in turn pushes on brain tissue.  Brain tissue may become displaced as a result, being pushed into areas occupied by CSF.  Since an intact skull is rigid and does not expand, the pressure of the CSF becomes pressurized (Newtons’s Third Law)  while simultaneously trapping brain tissue between a vise of swelling veins.    As focal areas of brain tissue that control specific physiologic functions become stressed, their functions become altered.  This pressure on brain tissue is likely the cause of symptoms associated with IIH.

THE MECHANISMS OF ICPDD: HOW INTRACRANIAL PRESSURES BECOME ELEVATED: PART ONE

 

 

Everybody knows the old adage about how to eat an elephant.   ICPDDs and their nuances certainly qualify, and the goal here is to present information in easily digestible bits.  This is the first bite.

While the reason/reasons (“etiology” it doctor-speak) a person develops IIH/PTC/etc. remain unknown and controversial, the physiology of how the pressure develops is actually quite straightforward:  ICPDDs reflect an increase in the pressure of fluid in and around the brain.  Thus, they are a result of a disruption in the dynamics of the fluids in and around the brain.  While CSF is most commonly discussed and treated, there is another fluid that actually rules everything, including CSF:

Blood.

FLUID DYNAMICS

Blood is the 800 lb Gorilla of the brain.  It is pumped into the brain primarily through the

Coronal view of Brain and Carotid arteries
The Carotid Arteries and their branches supply enormous volumes of blood to a nutrient-hungry brain. Note how close the brain is to the heart, which is just out of the bottom of the frame. Image courtesy of The Mayfield Brain Foundation.

carotid arteries at a rate of 750 to 1000 cc/minute when we are at rest; it courses through an estimated 100,000 miles of blood vessels delivering nutrients and oxygen to brain tissue.  Depleted blood is drained via the venous sinuses, a network of veins around the brain, and eventually through the jugular veins back to the heart.

Blood enters the brain at an average pressure (“Mean Arterial Pressure”, or MAP) of 90mm Hg.  It drains from the veins at a pressure of 15-20 mm Hg. Because the same amount of blood that flows into the brain has to flow out, and because venous pressure is lower than arterial pressure, the blood flow in veins must be higher to compensate (fluid dynamics, Bernoulli, a couple other Italian guys in there).  Suffice it to say that veins have to be able to carry away ALL blood that is pumped into the brain.  In addition to that important necessity, there are TWO factors of blood that must be considered in ICPDD: pressure (as expressed by MAP), and flow.  For the sake

venous sinuses
A very basic illustration of the venous sinuses responsible for carrying blood away from the brain and back to the heart.

of simplicity we will use heart rate as an indicator of blood flow.

 

 

 

 

 

 

 

 

 

 

CSF is a plasma like fluid that is made from blood in an interconnected network of small hollow areas in the brain known as ventricles.   It is produced at a very low

Ventricles of the brain
Blue areas represent CSF filled spaces. The approximate volume of the ventricles is 30 cc; total CSF in and around the brain is ~150cc. Image courtesy of the Mayfield Brain Foundation

rate of ~0.35 cc/minute from arterial blood.  Its rate of production is dependent on the am

ount of blood flowing into the brain.  CSF circulates through the ventricles and around the brain; this circulation is slow, with pulsations from blood vessels and body movement being the primary motivators.  It is primarily absorbed back into the blood circulation in the venous sinuses.

CSF is something of a Mystery Fluid.  Aside from cushioning and supporting the brain, it is thought to play a role in delivering nutrients and cleansing dead cells from the outer surface of the brain.  Deficiencies in CSF are associated with accumulations of these dead cells, known as plaques, which are themselves associated with dementias such as Alzheimers and Lewy Body.  Anyone with an ICPDD can tell you that “overdrainage”, ie, not enough ICP and/or CSF makes them feel weak and lethargic.   Again, suffice it to say that CSF is Very Important; otherwise, it would not be in our heads.

SUMMARY, PART ONE:  THE TWO FLUID POSTULATE

The dynamics of blood and CSF lay the groundwork for understanding ICPDDs.  ICP is a result of the interaction of these fluids inside the watertight, airtight, non-expandable skull.  These facts lead to what I call the Two Fluid Postulate:

“There are only two fluids inside the skull: blood and cerebrospinal fluid (CSF). Both are present in approximately equal volumes, 150cc. Only one flows in and out of the brain:  blood.  CSF is made from blood that enters the brain and absorbed back into the veins that drain blood away from the brain.  Intracranial pressure is the sum of the forces exerted within the skull by these two fluids.  Changes in the balance of CSF production/absorption and/or blood flow into and out of the brain will necessarily affect ICP.  Most critically, because the brain is encased in a rigid, non-expanding skull, ANY INCREASE IN ICP TRANSLATES INTO INCREASED PRESSURE DIRECTLY ON THE BRAIN.”

This is just a restatement of what is known as the Monro-Kellie Hypothesis from the 1890s by two Scottish physicians to explain what goes on inside the skull.

THE TAKE-AWAY:

CSF, while the most often discussed fluid in ICPDDs, is not the only fluid in the brain.  Blood, in fact, rules everything inside the skull, including CSF.  Because the volume inside the skull is fixed, and because there practically zero extra space in the skull, any net accumulation of CSF OR Blood will cause increased ICPs, and those increased ICPs exert direct pressure on the brain itself.

In Part 2, we will look at how the dynamics of blood and CSF become disrupted. 

 

 

 

 

 

 

Juice Boxes And My Brain: Who Knew?

“…March 2017 until I’m guessing November-ish 2017, I had a CSF leak that mucked up the attempts to control my ICP…”

 

Communication over the internet can be challenging.  Not like talking face to face; it’s easy to misunderstand what is being said, or why somebody is saying it.  That said, I want to lead with this:  ShuntWhisperer is just my story for about my ICPDD for whatever it’s worth.  ICPDDs and their treatment are poorly understood, doctors do the best they can with what is available now.  I think I’ve stumbled on to something…interesting… for no other reason than weird coincidence, and I don’t believe in coincidence.  Maybe this story it will help somebody, maybe it will spark conversation or thought, but it is absolutely, positively not intended to point fingers or place blame.  Despite the challenges of the last year, I would not change anything.  I’m just trying to make the most of it for the possible benefit of anyone who finds my experience useful in their journey, both patient and doctor.  I try to keep this as light as possible; any humor is just that, never intended to be irreverent.  The fact is I’m still here to type this because of the efforts of my neurosurgeon and the Grace of God.

Now, we return to our irregularly unscheduled post:

 

Is it seriously this “simple”?

So, last year, after I received my shunt, I had a pretty wild ride to put things mildly.  Despite all of it, I’m seriously grateful for everything.   There seem to be so many unknowns in ICPDDs; all through my experience I’ve tried to learn as much as possible about what is going on in my head and pass that information along.  It seems invaluable to me, and I pass it along not for my benefit, but in the hopes that it helps somebody else, and maybe fills in a small part of the overall puzzle.

#CROWDHEALING.

My Biggest Issue: wild swings in my ICP, with a distinct trend towards overdrainage. The higher the shunt was adjusted, the worse it got.   I never felt like I had enough CSF/ICP/MysteryFluid in my head.  Ever.

Until November, when thing began to change…

I was using the Whisperer Method to monitor blood flow into my head.  The numbers I got were deadly accurate both in how they related to my SOTD (Symptomology Of The Day).   The Cerebral Perfusion Coefficient (a figure that gave me a relative idea of how much blood was flowing into my brain along with the static pressure in the blood vessels) numbers stayed within a fixed range.  On the low end of the scale I considered myself “underperfused”, that is, not enough blood going into my brain to make enough CSF to keep up with normal losses along with…some other loss of CSF, someplace.  I thought it might be through my shunt, but I don’t think so now.  On the high side of the scale I felt like my head was going to burst, my shunt felt physically swollen, but perversely, I still felt as if I had no CSF in my head.  The “no CSF” feeling is one that I was well accustomed to as it was the same set of overdrainage symptoms for which I was hospitalized in June 2017, 3 months after getting my shunt.

The Deadly Accuracy of the numbers and symptom correlation held up until the end of November, when I noticed numbers and symptoms starting to diverge a little. Then a bit more. This divergence continued up until Christmas day, the last “BAD” day I had according to the old pattern.  Suddenly the numbers and symptoms no longer seemed to match.  I had no answer.

From Christmas on, suddenly the wild instability rapidly diminished.  Extremes of high and low ICPs became closer together.  No more apparent swelling of my shunt which is

Sophysa polaris
Propaganda Pic of My Shunt. The “Reservoir” is thick silicone, the rest inflexible plastic/metal. My baby.

made largely of rigid materials incapable of expansion.   It was as if either a blockage in my shunt had been cleared, or a leak in my head had been closed off.   Curiouser (TheWhisperers Unabridged Dictionary), the Cerebral Perfusion Numbers started climbing to new highs, up to 20% higher, without the usual symptoms high ICP symptoms of feeling like my head was going to explode.   January into March I actually felt pretty stable, still with bad days, but the best I had felt since getting the shunt.  This left me scratching my head, and that’s where I found The Answer To It All.

I’ve never been accused of being the sharpest knife or having a full picnic basket, etc.  A little slow at times.  So, a few days ago, I’m rubbing my head where the shunt catheter goes into my skull.  A slightly larger than dime sized hole created in my skull to allow the catheter to be poked into the hollow area in my brain.  No jokes about how easy it should be to hit a hollow area in my brain, please.  I’m delicate…

The skin over this hole, a.k.a. “craniotomy”, is slightly indented, normal for a surgical wound.  What I noticed is that I no longer noticed it anymore, because it was no longer changing shape.  All last year it changed contour with my ICP.  Sometimes it was like it was being sucked/pressed into my skull, other times, it was almost as if it was being pushed out under  conditions of high ICP.  It had become a sign I used to make note of in recording what was going on with my disorder, but now it was no longer changing….

Then, slowly, reality crept up on me.  I like to blame the fact that I have a tube in my brain for all these issues of slow comprehension; rather convenient really.  Never mind the fact I was slow before I got the shunt, but now I can point to it and say “See?  I have a tube in my brain.  I’m slow for a reason”, which sounds infinitely better than “I’ve always been slow.”

It was about the hole in my skull; a hole in bone.  A dime-ish sized hole was made in my skull, exposing the dura underneath.

9569
Rendering of how the shunt is placed into the brain. Gruesome Reality.

The dura is carefully opened, and a 3D guidance technique,  a catheter over a needle, sort of like an IV catheter for the brain, was then inserted through the  into the immense hollow area in my brain to drain CSF, after which the dura was sutured around the catheter and, my scalp repositioned and stapled shut. Joking aside, I have always appreciated the precision of this particular aspect of the procedure.  I had employed guidance techniques generated from 3D scans to place dental implants with extreme precision; the shunt cath placement is another level of precision entirely.

endoscopic-third-ventriculostomy-lg
Catheter inserted into ventricle in brain. Catheter is placed over a rigid metal guide tube which is withdrawn after the catheter is properly placed.

I joke that placing a shunt is not unlike poking a straw into the foil hole of a juice box.  No adult can put a straw in a juice box as well as a kid, who with a deft poke can stick that straw through the foil like a kung-fu master, creating an almost perfect hole to match the straw.  Perfect enough to suck juice through the straw, but we all know what happens if you squeeze the box with the straw plugged: juice seeps out around the straw, and the ratio of juice-leakage-to-squeeze is directly dependent on the cost of the shirt that is being stained, and inversely dependent on the time since same shirt was laundered.

Doubling factor if dry cleaning is involved (see: Whisperer’s Laws of Life 301).

If I have failed in my wordsmithing to create a clear mental image of this condition in your head, let me invite you to get a juice box, a bag of Capri Sun, a Corona Beer Pouch

Corona Juice Pouch
Too much time on my hands ; ), but a great idea nonetheless.

(see: Whisperer’s Intellectual Property Item 526), poke the straw through the foil (or get a child to do it for you, except for the Beer Pouch, of course), plug the end of the straw and squeeze the box/bag of juice.  See where it leaks – between the foil and the straw, right where the straw goes through the foil.  Except in my case, it was not juice, but CSF, leaking around the catheter where it penetrated the dura.  There is no magic seal here, and if ICP exceeds the pressure/flow settings of the shunt system, here is a place where CSF can leak.

I’ve been crafting, honing, polishing this for 3 days now, and each time I think about it, I keep wondering how many other shunt patients this might be a factor for, with any type of shunt, VP or LP.  The good news is there is a way to mitigate this leakage, or at least reduce the period of time it occurs through a simple surgical method to encourage faster growth of bone into the craniotomy.

As a dentist in my Previous Life, I was intimately familiar with the tissue of Bone.  Drilled a lot of holes in bone, grafted a lot of bone, moved bone from one place to another, bone, bone, bone, all day long, bone.  But, it paid the bills.  I know about bone in the human body, how it reacts to injury, how it heals – or doesn’t.  Without the fancy “bone bandage” known as a guided tissue membrane, bone may never fill in a defect completely, and if it does, it takes much longer.  A hole in the skull heals from the sides in and from the bottom up, over top of the dura, which by the way makes a dandy guided tissue membrane, at least on the brain side.  The issue here is the scalp tissue is a source of soft tissue that fills the hole in the skull well before bone has a chance.

Short story:  I didn’t get the fancy bandage for whatever reason.    I got a hole “stabbed” (actually carefully incised and then sutured, but for the sake of sensationalism…) in my dura (I wonder now if a child was brought into the operating room to do that part), a catheter inserted into my brain (with great care an precision), the latter hooked up to the shunt valve, and my scalp flopped back into place and stapled as the neurosurgeon asked the charge nurse if he still had time to make the late morning round of golf while the kid that poked the catheter into my brain sucked on a juice box under his surgical mask while sitting on a stool in the corner.  In all seriousness,  I can’t find a thing that says that shunt craniotomies should be grafted over; maybe they should be.

Bottom Line: March 2017 until I’m guessing November-ish 2017, I had a CSF leak that mucked up the attempts to control my ICP.  Ironically, whenever the shunt was “turned up” to a higher pressure setting, it made the problem worse.  Nothing sealed the dura to the tube.  CSF seeped between the tube and the dura, under the surgical flap, finding its way under my scalp, along the tube and around the shunt body, and likely farther.  In surgery the phenomenon is called tunneling, and the leakage of CSF around the catheter created what is known as a pseudomeningocele.  Finally in November a stage of healing of the craniotomy was reached that mitigated significant leaks.  The timing is right for the size of the hole.  However, since to guided tissue membrane/Bone Bandage was used, there is also a good chance the hole isn’t filled with bone, but with a thick scar tissue that may eventually turn to bone.  Whatever is in the hole, my head isn’t leaking from an unwanted place anymore.

Now:

Google the term Intracranial Hypotension (not “hypertension”) .  It’s a real thing.  Usually caused by an unwanted, unpredicted leak in the dura.  I believe this was a large part of the reason for my “wild ride” I went on after my shunt last year.  My concern now is who else may be suffering from it or may potentially suffer from it; possibly by posting this, a surgeon may be persuaded to add 10 minutes to the procedure and graft a VP shunt: I don’t know about LP shunts.

This theory also explains a new phenomenon:  the return in the last six weeks of my pre-shunt symptoms that were associated with high ICPs, the reason I got the shunt in the first place.  Not as bad yet, but getting there.   Fibro pain coming back, other bad stuff, BUT:  there is a clear silver lining. Regaining proper ICP balance may be as simple as turning my shunt down a notch.  As I write this I’m awaiting a CT to check my meninges, and I’ll post the results here.

(edit to add 5/22/18:  those symptoms are definitely back.  Time to check in with the neurosurgeon.)

The silver lining here is that I’ve gotten this far and have avoided at least one procedure that would likely have made things worse.  Early on last August when I was still having overdrainage symptoms despite having a shunt set at 200mm H2O PLUS a 250mm shunt assist, my neurosurgeon graciously offered to revise me to a higher pressure shunt valve.  I declined that offer because my personal situation was not amenable to having the surgery at that time, and I believed I could hold on until another option became available.  In retrospect, that higher pressure shunt would have likely made me worse.  I consulted with other neurosurgeons for their opinions, but I was never satisfied with their explanations based on nothing better than “gut feeling” and the personal records I had kept.  Now I believe I have that explanation, and I’m hopeful that a simple pressure adjustment in my shunt will restore some or all of the reduction in fibro pain, stop the return of the exercise intolerance which is again threatening to leave me bedridden for days after engaging in any physical exertion, and the sleep cycle disorders/insomnia which is back.  It is also my hope that this story helps somebody else, or sparks a thought process somewhere in the minds of doctors wrestling with a disorder that has so many unknowns attached.  I was told by one surgeon I was the “Unicorn” of this disorder (!); if so, at least now I know from whenst my horn grew…

Bottom Line:  without a good seal, CSF can and does leak around shunt catheters.  Pseudomeningoceles are a known postoperative possibility with shunts, but their frequency of occurrence is controversial. Secret or not, the answer may be a few added minutes to a shunt placement and a few hundred bucks for a bone bandage.  The bandage keeps soft tissue from the skin flap out of the craniotomy, encouraging more rapid and predictable bone healing around the shunt catheter.  Bone grafting material made from the patient’s own blood (Platelet Rich Fibrin), can be used to further seal the craniotomy before the bandage is placed and everything sewn/stapled shunt.  This is just an opinion I toss out there as a Disabled Dentist With a Hole In My Head.

It is my fervent hope that this clicks with ShuntWhisperer fans (both of you), maybe some docs, and that maybe, just maybe, addressing this small issue will make the post treatment course of other ICPDD patients and VP shunt recipients in general better.   As always, prayers to all.  Questions can now be sent via email to whispers@shuntwhisperer.com, and I am have setting a Twitter Feed specifically for ShuntWhisperer.

 

The Shunt Whisperer

May 19, 2018

Missing my wife in my life more and more every day: I love you, baby.