question: How does a shunt placement for treating hydrocephalus not lead to permanent disability given that a large amount of brain tissue is removed?
comment: You don't need to 'remove' tissue, persay, so much as you pierce through the issue. Think of like piercing a knife through a piece of bread--the knife goes through it, but you haven't removed the bread so much as the bread moved aside. Inserting an EVD drain does damage a very small amount of brain tissue, but it's minimal and there's rarely any lasting side effects. Regardless, relieving the problems of the hydrocephaleus is far more important. Lastly, the value apparatus is typically placed under the soft tissue of the head, outside the skull.
passages: There are a number of complications associated with shunt placement. Many of these complications occur during childhood and cease once the patient has reached adulthood. Many of the complications seen in patients require immediate shunt revision (the replacement or reprogramming of the already existing shunt). The common symptoms often resemble the new onset of hydrocephalus such as headaches, nausea, vomiting, double-vision, and an alteration of consciousness. Furthermore, in the pediatric population, the shunt failure rate 2 years after implantation has been estimated to be as high as 50%.
  
  Section::::Complications.:Infection.
   To evaluate the benefit of surgical shunt removal or externalization followed by removal, Wong et al. compared two groups: one with medical treatment alone and another with medical and surgical treatment simultaneously. 28 patients suffering from infection after ventriculoperitoneal shunt implantation over an 8-year period in their neurosurgical center were studied. 17 of these patients were treated with shunt removal or externalization followed by removal in addition to IV antibiotics while the other 11 were treated with IV antibiotics only. The group receiving both surgical shunt removal and antibiotics showed lower mortality – 19% versus 42% (p = 0.231). Despite the fact that these results are not statistically significant, Wong et al. suggest managing VP shunt infections via both surgical and medical treatment.
   Gait symptoms improve in ≥ 85% patients. Cognitive symptoms improve in up to 80% of patients when surgery is performed early in the disease course. Incontinence improves in up to 80% of patients, but only in ≤ 50–60% of patients with shunt implanted late in disease course. The most likely patients to show improvement are those who show only gait deviation, mild or no incontinence, and mild dementia. The risk of adverse events related to shunt placement is 11%, including shunt failure, infections such as ventriculitis, shunt obstruction, over- or under-drainage, and development of a subdural hematoma.
  
  Section::::Treatment.:Medications.
   An analysis of 17 studies published over the past 30 years regarding children with CSF shunt infections revealed that treating with both shunt removal and antibiotics successfully treated 88% of 244 infections, while antibiotic therapy alone successfully treated the CSF shunt infection in only 33% of 230 infections.
  
  While typical surgical methods of handling VP shunt infections involve removal and reimplantation of the shunt, different types of operations have used with success in select patients. 
   For suspected cases of NPH, CSF shunting is the first-line treatment. The most common type used to treat NPH is ventriculoperitoneal (VP) shunts, which drain CSF fluid to the peritoneal cavity. Adjustable valves allow fine-tuning of CSF drainage. NPH symptoms reportedly improve in 70–90% of patients with CSF shunt. Risk-benefit analyses have shown beyond any doubt that surgery for NPH is far better than conservative treatment or the natural course.
   Hydrocephalus is a condition in which cerebrospinal fluid (CSF) accumulates in the brain, potentially leading to brain damage and death. It is corrected by a shunt which drains excess CSF from the brain to the abdomen. Shunts fail, typically by obstruction – a life-threatening medical condition requiring the surgical replacement of the shunt. The symptoms of shunt failure are non-specific – headache, nausea, lethargy – so diagnostic tests must be conducted to rule in or rule out surgery. Current methods of diagnosing shunt malfunction, including CT Scan, MRI, radionuclide studies and shunt tap, have limitations and risks. These limitations and risks led to the development of ShuntCheck.
   The decision to use a shunt requires extensive discussion between doctor and patient, as this procedure carries with it greater risk of injury to the spinal cord, infection, blockage, or hemorrhage and may not necessarily work for all patients. Draining the syrinx more quickly does not produce better outcomes, but a shunt may be required if the fluid in the syrinx is otherwise unable to drain.
  
  In the case of trauma-related syringomyelia, the surgeon operates at the level of the initial injury. The syrinx collapses at surgery, but a tube or shunt is usually necessary to prevent re-expansion.
  
  Section::::Treatment.:Other.
   Treatment of a CSF shunt infection generally includes removal of the shunt and placement of a temporary ventricular reservoir until the infection is resolved. There are four main methods of treating ventriculoperitoneal (VP) shunt infections: (1) antibiotics; (2) removal of infected shunt with immediate replacement; (3) externalization of shunt with eventual replacement; (4) removal of infected shunt with external ventricular drain (EVD) placement and eventual shunt re-insertion. The last method is best with over 95% success rate.
  
  Section::::Complications.:Infection.:Medical treatment of shunt infection.
   Multi-Center Pediatric Outcomes Study 2013-2014 Boston Children's Hospital, Children's Hospital of Philadelphia, Johns Hopkins Hospital, Cleveland Clinic, University of Chicago Comer Children's Hospital, LeBonheur Children's Hospital and University of Texas Houston Children's Memorial Hermann Hospital will conduct an outcomes study of 400 symptomatic pediatric hydrocephalus patients during 2013-2014. In this NIH funded study, ShuntCheck results and the results of standard of care diagnostic tests will be compared to clinical outcome (shunt obstruction confirmed by surgery vs no-obstruction). This study seeks to demonstrate that
   Boston Children's Hospital 2010-2013 Dr. Madsen is testing 130 symptomatic and asymptomatic pediatric hydrocephalus patients to assess the diagnostic accuracy and clinical utility of the newer version of ShuntCheck including Micro-Pumper. This study was funded by the NIH.
   Steinbok et al. treated a case of recurrent VP shunt infections in an eczematous patient with a ventriculosubgaleal shunt for two months till the eczema healed completely. This type of shunt allowed them to avoid the area of diseased skin that acted as the source of infection.
  
  Jones et al. have treated 4 patients with non-communicating hydrocephalus that suffered VP shunt infections with shunt removal and third ventriculostomy. These patients were cured of the infection and have not required shunt re-insertion, thus showing the effectiveness of this procedure in these types of patients.
  
  Section::::Complications.:Obstruction.
   CURE Hydrocephalus: The program provides surgeons the training and equipment to combat the condition. Surgeons are trained in multiple forms of hydrocephalus treatment, including a “shuntless” procedure known as the Warf procedure, or ETV/CPC, where they identify the blockage in the brain and create a new path through which the accumulating fluid can drain naturally. With the surgery taking as little as 45 minutes, CURE claims the results are permanent and often much more stable than implanting a shunt.
   A common procedure performed in neurosurgery is the placement of ventriculo-peritoneal shunt (VP shunt). In pediatric practice this is often implemented in cases of congenital hydrocephalus. The most common indication for this procedure in adults is normal pressure hydrocephalus (NPH).
   The person was a married father of two children, and worked as a civil servant, leading an at least superficially normal life, despite having enlarged ventricles with a decreased volume of brain tissue. "What I find amazing to this day is how the brain can deal with something which you think should not be compatible with life", commented Dr. Max Muenke, a pediatric brain-defect specialist at the National Human Genome Research Institute. "If something happens very slowly over quite some time, maybe over decades, the different parts of the brain take up functions that would normally be done by the part that is pushed to the side."
   The diagnosis of CSF buildup is complex and requires specialist expertise. Diagnosis of the particular complication usually depends on when the symptoms appear, that is, whether symptoms occur when the person is upright or in a prone position, with the head at roughly the same level as the feet.
  
  Standardized protocols for inserting cerebral shunts have been shown to reduce shunt infections.
  
  Section::::History.
   Infection is a common complication that normally affects pediatric patients because they have not yet built up immunities to a number of different diseases. Normally, the incidence of infection decreases as the patient grows older and the body gains immunity to various infectious agents. 
   An intraventricular hemorrhage can occur at any time during or after a shunt insertion or revision. Intraparenchymal hemorrhages that are multi-focal in nature have also been described in the pediatric population following ventriculoperitoneal shunting. The hemorrhage can cause an impairment in shunt function which can lead to severe neurological deficiencies. Studies have shown that intraventricular hemorrhage can occur in nearly 31% of shunt revisions.
  
  Section::::Conditions requiring shunting.
  
  Below is a short list of known complications that can lead to hydrocephalus requiring shunting.
  
  Section::::Removing shunts.
   NeuroDx Development (NeuroDx) is an early commercial stage medical device company founded in 2008 by Fred Fritz (CEO), a serial life sciences entrepreneur, and Dr. Marek Swoboda (Chief Scientific Officer), a biosensor engineer, to address important unmet needs in the hydrocephalus market. The Company has developed two thermal dilution technologies for assessing shunt function in hydrocephalus patients, ShuntCheck-Micro-Pumper, an eight-minute test of CSF shunt flow, and Continuous Real Time (CRT) ShuntCheck, which uses thermal dilution to monitor changes in shunt flow over longer time periods. The Company's follow-on products, an implantable intracranial pressure monitoring device and a non-invasive monitor of intracranial pressure, are in proof of concept development.
   Shunt infection is a common problem and can occur in up to 27% of patients with a shunt. Infection can lead to long term cognitive defects, neurological problems, and in some cases death. Common microbial agents for shunt infection include "Staphylococcus epidermidis", "Staphylococcus aureus", and "Candida albicans". Further factors leading to shunt infection include shunt insertion at a young age (6 months old) and the type of hydrocephalus being treated. There is no strong correlation between infection and shunt type.
   Healthy brain development is also dependent on the signaling function of SHH. During embryonic development, SHH directs embryonic cells to organize in specific areas that later become specialized neural tissues, thus controlling the size and shape of brain structures.
  
  Section::::Occurrences.
  
  Diprosopus often occurs in combination with other congenital disorders, particularly anencephaly, neural tube defect and cardiac malformations. When present, the brain may show abnormalities ranging from partial to complete duplication of brain structures, and/or underdevelopment of brain tissues.
  
  Section::::Occurrences.:Humans.
   EVDs are a short-term solution to hydrocephalus, and if the underlying hydrocephalus does not eventually resolve, it may be necessary to convert the EVD to a cerebral shunt, which is a fully internalized, long-term treatment for hydrocephalus.
  
  Section::::EVD placement.
   Another leading cause of shunt failure is the blockage of the shunt at either the proximal or distal end. At the proximal end the shunt valve can become blocked due to the buildup of excess protein in the CSF. The extra protein will collect at the point of drainage and slowly clog the valve. The shunt can also become blocked at the distal end if the shunt is pulled out of the abdominal cavity (in the case of VP shunts), or from similar protein buildup. Other causes of blockage are overdrainage and slit ventricle syndrome.
  
  Section::::Complications.:Over drainage.
   The location of the shunt is determined by the neurosurgeon based on the type and location of the blockage causing hydrocephalus. All brain ventricles are candidates for shunting. The catheter is most commonly placed in the abdomen but other locations include the heart and lungs. Shunts can often be named after the route used by the neurosurgeon. The distal end of the catheter can be located in just about any tissue with enough epithelial cells to absorb the incoming CSF. Below are some common routing plans for cerebral shunts.
  
  Section::::Shunt location.:Shunt routing.
   During surgery, intraoperative neurophysiological monitoring of the facial, acoustic and lower cranial nerves can reduce the risk of injury. In particular, following the 1991 NIH National institutes of Health Acoustic Neuroma Consensus Panel, the use of facial nerve monitoring has become a standard practice in the United States to reduce the risk of facial paralysis.
  
  With massive tumors that compress the brainstem and cerebellum, staged surgical approaches or subtotal surgical resection followed by stereotactic radiosurgery may reduce the risks to life, brain and cranial nerves.
  
  Section::::Treatment.:Surgery.:Translabyrinthine approach.
   Boston Children's Hospital 2008-2009 Joseph R. Madsen MD tested 100 symptomatic and asymptomatic pediatric hydrocephalus patients using an earlier version of ShuntCheck during 2008-2009. His key findings, reported in Neurosurgery were
  
  BULLET::::- The ShuntCheck test is sensitive and specific for detecting shunt flow
  
  BULLET::::- But failure to detect flow does not predict the need for surgery
  
  University of South Florida 2008 Arthur E. Marlin MD and Sarah J Gaskill MD conducted ShuntCheck testing on 35 asymptomatic pediatric patients with similar results.
  
  These findings led to the development of the Micro-Pumper.
  
presuppositions: During a a shunt placement, a large amount of brain tissue is removed. Brain tissue is removed during a shunt placement for treating hydrocephalus.
corrections: Brain tissue is just pierced, reducing the amount of brain tissue that is actually removed. Brain tissue is pierced rather than removed during a shunt placement for treating hydrocephalus.
raw_presuppositions: During a a shunt placement, a large amount of brain tissue is removed. Brain tissue is removed during a shunt placement for treating hydrocephalus.
raw_corrections: Brain tissue is just pierced, reducing the amount of brain tissue that is actually removed. Brain tissue is pierced rather than removed during a shunt placement for treating hydrocephalus.