Naina L. Gross

Proximal ventricular shunt malfunctions in children: Factors associated with failure.

Ventricular shunt failures and subsequent revisions are a significant source of patient morbidity. We conducted a review of pediatric patients undergoing placement or revision of ventricular shunts at our institution between January 2007 and December 2008. Patients were followed through to July 2014. Data collected included patient demographics, shunt history and indication for procedure, approach taken for shunt placement, and location of shunt tip in relation to the foramen of Monro. Univariate and multivariate analyses were conducted to identify factors associated with proximal failure. A total of 87 procedures were identified in 40 patients, consisting of 23 initial placements and 64 revisions. Thirty-nine proximal catheter malfunctions were identified. Indications for shunt placement included Chiari II malformation (33%) and intraventricular hemorrhage (33%). Mean follow-up period was 5.5 years. Median time to shunt failure was 1.57 years. In the multivariate model, younger age at placement was associated with decreased time to proximal failure (hazard ratio [HR]=0.80 per increasing year of age, 95% confidence interval [CI] 0.64-0.98). Both anterior approach (HR=0.39, 95% CI 0.23-0.67) and farther distance to foramen of Monro (HR=0.02 per increasing 10mm, 95% CI 0.00-0.22) were associated with increased time to proximal failure when the catheter tip was located within the contralateral lateral ventricle. Optimizing outcomes in patients with shunt-dependent hydrocephalus continues to be a challenge. Despite unsatisfactory outcomes, particularly in the pediatric population, few conclusions can be drawn from studies assessing operative variables.

Spinal cord detethering in children with tethered cord syndrome and Chiari type 1 malformations

We discuss the association between tethered cord syndrome (TCS) and Chiari type 1 malformation (CM1), and report on the surgical outcomes of children with CM1 and TCS who underwent sectioning of the filum terminale (SFT). The relationship between TCS and CM1 is unclear. A retrospective review of 170 consecutive spinal cord detetherings between 2008 and 2012 was performed. We identified 17 children with CM1 who underwent SFT. Information regarding clinical presentation, radiographic findings, surgical procedures, and clinical outcomes was analyzed. A mean tonsillar herniation of 10.0mm (range: 5-21) was noted. Children with a fatty or thickened filum terminale demonstrated a greater amount of tonsillar displacement (p<0.005). A low conus medullaris was found in 12 children and a syrinx was present in three. The preoperative symptoms improved in all children. The postoperative MRI (mean 21.8 months) revealed an unchanged tonsillar position in all but one child. No worsening of neurologic function was noted. Pediatric patients who have both CM1 and TCS, but do not demonstrate classic Chiari-related symptoms, may experience symptomatic improvement after filum terminale sectioning.

Migration of a ventricular tapping reservoir into the third ventricle.

The authors present a case of migration of a ventricular tapping system into the third ventricle of a 6-year-old boy who is was born prematurely. As an infant, the patient was treated with serial lumbar punctures for hydrocephalus associated with intraventricular hemorrhage. The patient progressed to requiring a ventricular tapping reservoir and eventually a ventriculoperitoneal shunt. The patient presented for suspected shunt malfunction 4 years after placement of his ventriculoperitoneal shunt, and the migrated ventricular tapping system was discovered. The authors discuss several management strategies that could be used to prevent this complication.

Risk of failure in pediatric ventriculoperitoneal shunts placed after abdominal surgery

OBJECTIVE Experience has led us to suspect an association between shunt malfunction and recent abdominal surgery, yet information about this potential relationship has not been explored in the literature. The authors compared shunt survival in patients who underwent abdominal surgery to shunt survival in our general pediatric shunt population to determine whether such a relationship exists. METHODS The authors performed a retrospective review of all cases in which pediatric patients underwent ventriculoperitoneal shunt operations at their institution during a 7-year period. Survival time in shunt operations that followed abdominal surgery was compared with survival time of shunt operations in patients with no history of abdominal surgery. Univariate and multivariate analyses were used to identify factors associated with failure. RESULTS A total of 141 patients who underwent 468 shunt operations during the period of study were included; 107 of these 141 patients had no history of abdominal surgery and 34 had undergone a shunt operation after abdominal surgery. Shunt surgery performed more than 2 weeks after abdominal surgery was not associated with time to shunt failure (p = 0.86). Shunt surgery performed within 2 weeks after abdominal surgery was associated with time to failure (adjusted HR 3.6, 95% CI 1.3-9.6). CONCLUSIONS Undergoing shunt surgery shortly after abdominal surgery appears to be associated with shorter shunt survival. When possible, some patients may benefit from shunt placement utilizing alternative termini.

Iatrogenic intradural arachnoid cyst following tethered cord release in a child

Iatrogenic arachnoid cysts represent uncommon complications of intradural spinal procedures. Here we present the case of a 7-year-old girl who was found to have a symptomatic, pathologically proven, intradural arachnoid cyst 3 years following tethered cord release. The patient originally presented with abnormal urodynamics testing and was found to have fatty infiltration in her filum terminale. She underwent sectioning of the filum terminale without complications. The patient presented 3 years later with pain and neurogenic claudication. The patient was successfully treated with subarachnoid cyst fenestration with resolution of her bilateral lower extremity pain. Spinal intradural arachnoid cysts represent an important, though rare, postoperative complication of dural opening.