Treatment of Secondary Tonsillar Herniation by Lumboperitoneal Shunt Revision

Tonsillar herniation as a complication of lumboperitoneal shunt: case report and literature review

Tonsillar herniation is a rare and seldom reported complication after lumboperitoneal (LP) shunting. There have been only few reports that have presented possible options for treatment with varying degrees of success. In this report, we describe a rare case of tonsillar herniation after LP shunting and review related literature.A 17-year-old girl with hydrocephalus related to a traumatic brain injury underwent implantation of an adjustable pressure shunt (valve setting2.5) and a small lumen peritoneal catheter via the L4-L5 interspinal space. One month later, she was admitted to the emergency room with a Glasgow Coma Scale score ofE1M1Vt and dilated pupil. Image studies demonstrated new-onset tonsillar herniation and a mild cervical syrinx. Emergent suboccipital decompressive craniectomy, C1 laminectomy, and duraplasty were performed. This was followed with ligation of the LP shunt and implantation of a ventriculoperitoneal (VP) shunt a few days later. The patient's Glasgow Coma Scale score gradually recovered to 6, which was her previous neurologic status.Tonsillar herniation as a complication after LP shunting is best treated with decompression, ligation or removal of the LP shunt, and a shift to a VP shunt. The tonsillar herniation should be rapidly addressed to avoid persistent symptoms or progression of the neurologic deficits.

Lumboperitoneal Shunts - Patient Selection, Technique, and Complication Avoidance: An Experience of 426 Cases

Background

Lumboperitoneal shunt is a known procedure for communicating hydrocephalus. Being an extracranial procedure, it can also be utilized in normal-sized ventricles.

Objective

To report our experience of lumboperitoneal shunt done with a minimal follow-up of 12 months with an emphasis on patient selection, technique, and complication avoidance.

Methods

This was a retrospective analysis of patients who underwent LP shunt during October 2014-October 2019 at the authors' institute. Inclusion criteria were patients with communicating hydrocephalus due to tubercular meningitis, normal pressure hydrocephalus, idiopathic intracranial hypertension, and postoperative refractory cerebrospinal fluid leaks. Data were collected for demographics, Glasgow coma scale and Glasgow outcome scale, vision, gait, memory, urinary incontinence, failed attempts, and complications.

Results

A total of 426 patients underwent the LP shunt procedure. The commonest indication was tubercular meningitis followed by idiopathic intracranial hypertension and normal pressure hydrocephalus. Age ranged from 16 to 72 years. There were 255 male and 171 female patients. The mean follow-up was 41 ± 8 months. Overall, 301 patients (70.6%) had neurological improvement. Shunt-related complications occurred in 112 (26.29%) patients, of which shunt block was the commonest. Other complications were infection in 17 (3.9%) patients and extrusion in four (0.9%) patients. Transient postural headache was seen in 46 (10.7%) patients, which gradually improved.

Conclusion

Lumboperitoneal shunt was found to be a safe and effective treatment in appropriately selected communicating hydrocephalus patients. A meticulous technique reduces the complication rate.

Shunt dependency syndrome and acquired Chiari malformation secondary to cerebrospinal fluid diversion procedures: a 9-year longitudinal observation

BACKGROUND

Shunt dependency syndrome is a rare long-term complication of cystoperitoneal (CP) shunting for intracranial arachnoid cysts, which is characterized by acute intracranial hypertension with normal-sized or small ventricles. Additionally, acquired Chiari type I malformations (ACIM) could be infrequently secondary to extrathecal shunt drainage of cerebrospinal fluid.

CASE REPORT

We described a 12-year-old boy who developed shunt dependency syndrome following a CP shunting for treating a temporal arachnoid cyst. To manage this rare complication, we placed a lumboperitoneal (LP) shunt. During the follow-up period, shunt-induced ACIM and concomitant syringomyelia were noted.

CONCLUSION

Shunt dependency syndrome is a rare complication secondary to CP shunting in the treatment of temporal arachnoid cysts, and LP shunting is an effective option to relieve the intracranial hypertension. However, the clinicians should be alert to the ACIM as a rare late complication of cerebrospinal fluid diversion procedures, and the potential protecting effect of the programmable valve should be emphasized.

Upward Translation of Cerebellar Tonsils following Surgical Expansion of Supratentorial Cranial Vault: A Unified Biomechanical Explanation of Chiari Type I

Cerebellar tonsils moved significantly upward in 3 patients with Chiari type I who underwent supratentorial cranial vault expansion to alleviate intracranial pressure related to multisutural craniosynostosis. The Chiari type I deformities in these patients were the biomechanical consequence of posterior fossa-cerebellar disproportion caused by supratentorial craniocerebral disproportion secondary to multisutural craniosynostosis. The authors postulate that all cases of Chiari type I deformity share the sine qua non feature of posterior fossa-cerebellar disproportion.

Miethke DualSwitch Valve in lumboperitoneal shunts

INTRODUCTION

Despite the existence of wide variety of shunt systems, physiological regulation of intracranial pressure in shunted patients remains a utopian dream. Lumboperitoneal shunts (LPS) have long been used for treating idiopathic intracranial hypertension and other types of "communicating" hydrocephalus. Although they can provide rapid and effective symptom resolution, cerebrospinal fluid (CSF) over-drainage remains a common complication of LPS. We introduce the use of the Miethke DualSwitch Valve (M-DSV) for LPS and describe our preliminary experience with these valves in managing and avoiding CSF over-drainage. This is the first description of the use of M-DSV for LPS.

MATERIALS AND METHODS

Over 6 months, we treated five patients with LPS using M-DSV. Prior to the use of the M-DSV, four patients experienced significant over-drainage symptoms secondary to LPS. Data was collected prospectively, including preoperative details and clinical outcome.

RESULTS

Five patients (age range, 22 to 71 years) were operated upon. Three patients had pseudotumor cerebri, one patient had an LPS for treatment of a posterior fossa pseudomeningocele, and one had an LPS for treatment of cauda equina syndrome secondary to lumbar dural ectasia. Four patients had a history of clinical over-drainage secondary to pre-existing LPS systems. The fifth patient had an LPS revision after the previous LPS migrated. Follow-up ranged from 5 to 11 months (mean, 7.8 ± 3 months). All patients had a good outcome with immediate resolution of over-drainage symptoms and are currently asymptomatic.

CONCLUSIONS

The use of M-DSV in LPS is an effective alternative for avoiding posture-related over-drainage and managing patients with LPS-related over-drainage symptoms. Further experience is required to address the long-term outcome, balancing sufficient drainage while preventing over-drainage.

Flow dynamics in lumboperitoneal shunts and their implications in vivo

Object

Lumboperitoneal shunting is the standard treatment for pseudotumour cerebri or idiopathic intracranial hypertension. Complications are common, particularly the problem of overdrainage leading to low pressure symptoms. The authors designed a simple experiment using catheters of different lengths that drained at different pressure heads and with different vertical drops to study the flow characteristics in these shunts and determine the optimal catheter placement and length that would reduce the occurrence of low pressure headaches.

Methods

The flow rates through catheters of 3 different lengths (60, 83, and 100 cm) with the same internal radius, at 3 different pressure heads (15, 25, and 35 cm H2O to simulate 3 different placements in the lumbar theca), and 3 different vertical drops (10, 20, and 30 cm to simulate the possible effect of siphoning) were measured and the results analyzed.

Results

Application of Poiseuille's law and Bernoulli's principle to the experimental design shows that the volume of flow is directly proportional to the sum of the pressure head and the vertical drop and inversely proportional to the length of the catheter. The flow rate through the standard catheter lengths over the course of 24 hours can be abnormally high. An attempt to predict the optimal catheter length was made.

Conclusions

Although the catheter position in the theca and abdomen cannot be altered significantly and the internal radius of the tube cannot be reduced further without increasing the risk of blockage, the length of the tube can be increased to combat overdrainage. The authors suggest that currently available catheters are too short.