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Concept: Hydrocephalus

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INTRODUCTION: Symptomatic subdural hematoma development is a constant concern for patients who have undergone cerebrospinal fluid shunting procedures to relieve symptoms related to normal-pressure hydrocephalus. Acute subdural hematomas are of particular concern in these patients as even minor head trauma may result in subdural hematoma formation. The presence of a ventricular shunt facilitates further expansion of the subdural hematoma and often necessitates surgical treatment, including subdural hematoma evacuation and shunt ligation. CASE PRESENTATION: We present the case of a 63-year-old North American Caucasian man with normal-pressure hydrocephalus with an adjustable valve ventriculoperitoneal shunt who developed an acute subdural hematoma after sustaining head trauma. Conservative treatment was favored over operative evacuation because our patient was neurologically intact, but simple observation was considered to be too high risk in the setting of a low-pressure ventriculoperitoneal shunt. Thus, the valve setting on the ventriculoperitoneal shunt was increased to its maximum pressure setting in order to reduce flow through the shunt and to mildly increase intracranial pressure in an attempt to tamponade any active bleeding and limit hematoma expansion. A repeat computed tomography scan of the head six days after the valve adjustment revealed complete resolution of the acute subdural hematoma. At this time, the valve pressure was reduced to its original setting to treat symptoms of normal-pressure hydrocephalus. CONCLUSIONS: Programmable shunt valves afford the option for non-operative management of acute subdural hematoma in patients with ventricular shunts for normal-pressure hydrocephalus. As illustrated in this case report, increasing the shunt valve pressure may result in rapid resolution of the acute subdural hematoma in some patients.

Concepts: Traumatic brain injury, Intracranial pressure, Cerebrospinal fluid, Hydrocephalus, Subdural hematoma, Hematoma, Subdural space

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Biofilms are the source of persistent infections of many pathogenic microbes. They are responsible for nosocomial infection and also associated with many surgical conditions including indwelling medical devices such as ventriculoperitoneal shunt. A significant problem encountered in shunt procedures is obstruction followed by infection, with infection rate ranging from 2% to 27%, often with poor outcome.

Concepts: Immune system, Bacteria, Microbiology, Pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, Hydrocephalus, Clostridium difficile

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Current therapies for reducing raised intracranial pressure (ICP) under conditions such as idiopathic intracranial hypertension or hydrocephalus have limited efficacy and tolerability. Thus, there is a pressing need to identify alternative drugs. Glucagon-like peptide-1 receptor (GLP-1R) agonists are used to treat diabetes and promote weight loss but have also been shown to affect fluid homeostasis in the kidney. We investigated whether exendin-4, a GLP-1R agonist, is able to modulate cerebrospinal fluid (CSF) secretion at the choroid plexus and subsequently reduce ICP in rats. We used tissue sections and cell cultures to demonstrate expression of GLP-1R in the choroid plexus and its activation by exendin-4, an effect blocked by the GLP-1R antagonist exendin 9-39. Acute treatment with exendin-4 reduced Na(+)- and K(+)-dependent adenosine triphosphatase activity, a key regulator of CSF secretion, in cell cultures. Finally, we demonstrated that administration of exendin-4 to female rats with raised ICP (hydrocephalic) resulted in a GLP-1R-mediated reduction in ICP. These findings suggest that GLP-1R agonists can reduce ICP in rodents. Repurposing existing GLP-1R agonist drugs may be a useful therapeutic strategy for treating raised ICP.

Concepts: Adenosine triphosphate, Intracranial pressure, Receptor antagonist, Agonist, Cerebrospinal fluid, Hydrocephalus, Inverse agonist, Meningitis

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OBJECTIVE Recent advances in optics and miniaturization have enabled the development of a growing number of minimally invasive procedures, yet innovative training methods for the use of these techniques remain lacking. Conventional teaching models, including cadavers and physical trainers as well as virtual reality platforms, are often expensive and ineffective. Newly developed 3D printing technologies can recreate patient-specific anatomy, but the stiffness of the materials limits fidelity to real-life surgical situations. Hollywood special effects techniques can create ultrarealistic features, including lifelike tactile properties, to enhance accuracy and effectiveness of the surgical models. The authors created a highly realistic model of a pediatric patient with hydrocephalus via a unique combination of 3D printing and special effects techniques and validated the use of this model in training neurosurgery fellows and residents to perform endoscopic third ventriculostomy (ETV), an effective minimally invasive method increasingly used in treating hydrocephalus. METHODS A full-scale reproduction of the head of a 14-year-old adolescent patient with hydrocephalus, including external physical details and internal neuroanatomy, was developed via a unique collaboration of neurosurgeons, simulation engineers, and a group of special effects experts. The model contains “plug-and-play” replaceable components for repetitive practice. The appearance of the training model (face validity) and the reproducibility of the ETV training procedure (content validity) were assessed by neurosurgery fellows and residents of different experience levels based on a 14-item Likert-like questionnaire. The usefulness of the training model for evaluating the performance of the trainees at different levels of experience (construct validity) was measured by blinded observers using the Objective Structured Assessment of Technical Skills (OSATS) scale for the performance of ETV. RESULTS A combination of 3D printing technology and casting processes led to the creation of realistic surgical models that include high-fidelity reproductions of the anatomical features of hydrocephalus and allow for the performance of ETV for training purposes. The models reproduced the pulsations of the basilar artery, ventricles, and cerebrospinal fluid (CSF), thus simulating the experience of performing ETV on an actual patient. The results of the 14-item questionnaire showed limited variability among participants' scores, and the neurosurgery fellows and residents gave the models consistently high ratings for face and content validity. The mean score for the content validity questions (4.88) was higher than the mean score for face validity (4.69) (p = 0.03). On construct validity scores, the blinded observers rated performance of fellows significantly higher than that of residents, indicating that the model provided a means to distinguish between novice and expert surgical skills. CONCLUSIONS A plug-and-play lifelike ETV training model was developed through a combination of 3D printing and special effects techniques, providing both anatomical and haptic accuracy. Such simulators offer opportunities to accelerate the development of expertise with respect to new and novel procedures as well as iterate new surgical approaches and innovations, thus allowing novice neurosurgeons to gain valuable experience in surgical techniques without exposing patients to risk of harm.

Concepts: Surgery, Psychometrics, Validity, Cerebrospinal fluid, Neurosurgery, Hydrocephalus, Content validity, Special effects

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A 39-year-old white man presented with intractable headaches and papilledema. The initial workup, with normal MRI and MRV but elevated cerebrospinal fluid protein raised concerns about the putative diagnosis of idiopathic intracranial hypertension, and his condition remained refractory to maximum medical treatment. Angiography revealed cerebral venous sinus stenosis, thought to represent chronic thrombosis. The diagnosis and treatment of cerebral venous sinus stenosis and thrombosis are discussed.

Concepts: Intracranial pressure, Neurology, Cerebrospinal fluid, Hydrocephalus, Meningitis, Headache, Cerebral venous sinus thrombosis, Dural venous sinuses

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The authors illustrate the cases of two children with headaches, one diagnosed with Chiari type 1 malformation and the other with hydrocephalus, who played wind instruments. Both patients manifested that their headaches worsened with the efforts made during playing their musical instruments. We briefly comment on the probable role played by this activity on the patients' intracranial pressure and hypothesize that the headaches might be influenced by increases in their intracranial pressure related to Valsalva maneuvers. We had serious doubts on if we should advise our young patients about giving up playing their music instruments.

Concepts: Intracranial pressure, Hydrocephalus, Music, Arnold-Chiari malformation, Musical instrument, Oboe

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OBJECTIVE: Ventriculoperitoneal (VP) shunt surgery is the predominant mode of therapy for patients with hydrocephalus. However, it has potential complications that may require multiple surgical procedures during a patient’s lifetime. The objective of this study is to review our long-term experience and evaluate the risk factors for VP shunt failure after initial shunt surgery and after subsequent revisions. METHODS: Patients who underwent VP shunt surgery for hydrocephalus were included. Medical charts, operative reports, imaging studies, and clinical follow-up evaluations were reviewed and analyzed retrospectively. RESULTS: A total of 1015 patients with the median age of 41.6 (range, 0 - 90.3) years at the time of VP shunt surgery were included. The mean and median follow up was 9.2 and 6.5 years, respectively. Adult patients (≥ 17 years) accounted for 70.0% of the patients. The overall shunt failure rate requiring shunt revision(s) was 46.3% and the majority of shunt revisions occurred during the first 6 months after shunt placement. The shunt revision rate was significantly higher in pediatric (< 17 years) than in adult (> 17 years) patients (78.2% vs.32.5%, P < 0.001). Age at the time of shunt surgery, prior treatments to shunt surgery, etiology of hydrocephalus, and hydrocephalus type were independently associated with the incidence of shunt revision. Age at shunt placement and gender were significantly associated with multiple shunt revisions. Among population with at least one shunt revision, pediatric patients had significantly lower shunt survival rate and shorter median time to subsequent shunt revision than the adult (> 17 years) patients; male patients had higher odds for multiple revisions than females. CONCLUSION: The findings of the study indicate that age at shunt placement, etiology of hydrocephalus, type of hydrocephalus, and prior treatments before shunt surgery were independently significantly associated with the shunt survival. Prospective controlled studies are required to address the observed associations between the risk factors and incidence of shunt revisions in these patients.

Concepts: Time, Medicine, Surgery, Median, Physician, Arithmetic mean, Hydrocephalus, Cerebral shunt

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In a previous study we found significantly decreased N-acetyl aspartate (NAA) and total N-acetyl (tNA) groups in the thalamus of patients with idiopathic normal pressure hydrocephalus (iNPH) compared with healthy individuals (HI). No significant difference between the groups could be found in the frontal deep white matter (FDWM).

Concepts: Dementia, White matter, Neurosurgery, Pressure, Hydrocephalus, Normal pressure hydrocephalus

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PURPOSE: Management of hydrocephalus with insertion of ventriculoperitoneal (VP) shunt is associated with significant complications in both adult and pediatric patients. These may be more common in developing countries due to poor economic conditions and a dearth of available resources. We report a 6 years' experience with VP shunt insertion in pediatric patients from a developing country, focusing particularly on factors affecting shunt failure. METHODS: Patients aged below 15 years, who had undergone insertion of VP shunts for hydrocephalus during the years 2006 to 2011, were included. A retrospective analysis of shunt survival was performed using Kaplan-Meier curves and Logrank (Cox-Mantel) test. RESULTS: Among the total 113 patients, the most common etiologies of hydrocephalus were congenital hydrocephalus (19.5 %), brain tumors (14.2 %), and postcranial surgery (13.3 %). Overall shunt failure at a mean follow-up of 11 months was 23 % with the median time to first shunt failure being 68 days. Shunt survival was worse in patients with meningitis (p = 0.024), aqueductal stenosis (p = 0.008), postcranial surgery hydrocephalus (p = 0.006), Caesarean mode of delivery (p = 0.036), congenital abnormalities (p = 0.031), and a past history of surgical excision of mass lesion (p = 0.044).Frequency of shunt failure was also significantly affected by the location of brain tumor (p = 0.015) and prematurity (p = 0.015). CONCLUSION: Premature infants still have a higher rate of shunt failure. Patients with meningitis, aqueductal stenosis, postcranial surgery hydrocephalus, congenital abnormalities, and a past history of surgical excision of mass lesion may have early shunt failure. However, the frequency of shunt failure that we observed (23 %) was much lower than that quoted earlier in the literature and this may be a consequence of rigorous periodic evaluation of patients with VP shunt in situ.

Concepts: Medicine, Cancer, Oncology, Surgery, Intracranial pressure, Brain tumor, Hydrocephalus, Cerebral shunt

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Object Ventriculoperitoneal (VP) shunt placement remains the mainstay treatment for pediatric hydrocephalus. These devices have a relatively high complication and failure rate, often requiring multiple revisions. The authors present a single institution’s experience of pediatric patients treated with VP shunts. With an average follow-up time of 20 years, this study is among the longest reports of VP shunt revision in the literature to date. Hydrocephalus origins, shunt revision rates, and causes of shunt failure are described. Patients who underwent their first shunt revision more than 10 years after initial shunt placement were also explored. Methods A retrospective chart review was performed on all pediatric patients who underwent VP shunt placement from January 1990 through November 1996 at the University of Rochester Medical Center. Only patients who had at least 15 years of follow-up since their initial shunting procedure were included. Results A total of 234 procedures were performed on 64 patients, with a mean follow-up of 19.9 years. Patients ranged from a few days to 17.2 years old when they received their original shunt, with a median age of 4 months; 84.5% of the patients required 1 or more shunt revisions and 4.7% required 10 or more. Congenital defects, Chiari Type II malformations, tumors, and intraventricular hemorrhage were the most common causes of hydrocephalus. Overall, patients averaged 2.66 revisions, with proximal (27%) and distal (15%) catheter occlusion, disconnection (11%), and infection (9%) comprising the most common reasons for shunt malfunction. Notably, 12.5% of patients did not require their first shunt revision until more than 10 years after initial device placement, a previously undescribed finding due to the short follow-up duration in previous studies. Conclusions This long-term retrospective analysis of pediatric VP shunt placement revealed a relatively high rate of complications with need for shunt revision as late as 17 years after initial placement. Catheter occlusion represented a significant percentage of shunt failures. Cerebrospinal fluid shunting has a propensity for mechanical failure and patients with VP shunts should receive follow-up through the transition to adulthood.

Concepts: Intracranial pressure, Cerebrospinal fluid, Failure, Congenital disorder, Hydrocephalus, Congenital disorders, Arnold-Chiari malformation, Cerebral shunt