Peter W. Carmel and James Drake
Sagun Tuli, James Drake, Jerry Lawless, Melanie Wigg and Maria Lamberti-Pasculli
Repeated cerebrospinal fluid (CSF) shunt failures in pediatric patients who have undergone neurosurgical procedures are common, and they are a significant cause of morbidity and occasionally mortality. To date, the risk factors for repeated failure have not been established. By performing survival analysis for repeated events, the authors examined the effects of patient characteristics, shunt hardware, and surgical details in a large cohort of patients.
During a 10-year period all pediatric patients with hydrocephalus requiring CSF diversionary procedures were included in a prospective single-institution observational study. Patient characteristics were defined as age, gender, weight, head circumference; American Society of Anesthesiology class, and the cause of hydrocephalus. Surgical details included whether the procedure was performed on an emergency or nonemergency basis, use of antibiotics, concurrent other surgical procedures, and the duration of surgical procedure. Details on shunt hardware included the type of shunt, the valve system, whether the shunt system included multiple or complex components, the type of distal catheter, site of the shunt, and side on which the shunt was placed.
Repeated shunt failures were assessed with multivariable time-to-event analysis (using the Cox regression model). Conditional models (as established by Prentice, et al.) were formulated for gap times (that is, times between successive shunt failures).
There were 1183 shunt failures in 839 patients. Failure time from the first shunt procedure was an important predictor for the second and third episodes of failures, thus establishing an association between the times to failure within individual patients. Age of less than 40 weeks gestation at time of the first shunt implantion carried a hazard ratio (HR) of 2.49 (95% confidence interval [CI] 1.68-3.68) for the first failure and remained high for subsequent episodes of failure. Age of 40 weeks to 1 year (at the time of the initial surgery) also proved to be an important predictor of first shunt malfunctions (HR 1.77, 95% CI 1.29-2.44). The cause of hydrocephalus was significantly associated with the risk of initial failure and, to a lesser extent, later failures. Concurrent other surgical procedures were associated with an increased risk of failure.
The patient's age at the time of initial shunt placement and the time interval since previous surgical revision are important predictors of repeated shunt failures in the multivariable model. Even after adjusting for age at first shunt insertion as well as the cause of hydrocephalus there is significant association between repeated failure times for individual patients.
Sagun Tuli, James Drake, Jerry Lawless, Melanie Wigg and Maria Lamberti-Pasculli
Object. Repeated cerebrospinal fluid (CSF) shunt failures in pediatric patients are common, and they are a significant cause of morbidity and, occasionally, of death. To date, the risk factors for repeated failure have not been established. By performing survival analysis for repeated events, the authors examined the effects of patient characteristics, shunt hardware, and surgical details in a large cohort of patients.
Methods. During a 10-year period all pediatric patients with hydrocephalus requiring CSF diversion procedures were included in a prospective single-institution observational study. Patient characteristics were defined as age, gender, weight, head circumference, American Society of Anesthesiology class, and cause of hydrocephalus. Surgical details included whether the procedure was performed on an emergency or nonemergency basis, use of antibiotic agents, concurrent surgical procedures, and duration of the surgical procedure. Details on shunt hardware included: the type of shunt, the valve system, whether the shunt system included multiple or complex components, the type of distal catheter, the site of the shunt, and the side on which the shunt was placed.
Repeated shunt failures were assessed using multivariable time-to-event analysis (by using the Cox regression model). Conditional models (as established by Prentice, et al.) were formulated for gap times (that is, times between successive shunt failures).
There were 1183 shunt failures in 839 patients. Failure time from the first shunt procedure was an important predictor for the second and third episodes of failure, thus establishing an association between the times to failure within individual patients. An age younger than 40 weeks gestation at the time of the first shunt implantion carried a hazard ratio (HR) of 2.49 (95% confidence interval [CI] 1.68–3.68) for the first failure, which remained high for subsequent episodes of failure. An age from 40 weeks gestation to 1 year (at the time of the initial surgery) also proved to be an important predictor of first shunt malfunctions (HR 1.77, 95% CI 1.29–2.44). The cause of hydrocephalus was significantly associated with the risk of initial failure and, to a lesser extent, later failures. Concurrent other surgical procedures were associated with an increased risk of failure.
Conclusions. The patient's age at the time of initial shunt placement and the time interval since previous surgical revision are important predictors of repeated shunt failures in the multivariable model. Even after adjusting for age at first shunt insertion as well as the cause of hydrocephalus, there is significant association between repeated failure times for individual patients.
Report of three cases
Walter J. Hader, James Drake, Douglas Cochrane, Owen Sparrow, Edward S. Johnson and John Kestle
✓ Late failure following successful third ventriculostomy for obstructive hydrocephalus is rare, and death caused by failure of a previously successful third ventriculostomy has been reported only once. The authors present three patients who died as a result of increased intracranial pressure (ICP) after late failure of a third ventriculostomy.
Through a collaborative effort, three patients were identified who had died following third ventriculostomy at one of the authors' institutions. A 13-year-old girl with neurofibromatosis Type 1 underwent third ventriculostomy for obstructive hydrocephalus caused by a tectal lesion. Three years later her condition deteriorated rapidly over the course of 6 hours and she was found dead at home. A 4-year-old boy treated with third ventriculostomy for aqueductal stenosis presented 2 years postoperatively with symptoms of increased ICP. This patient suffered a cardiorespiratory arrest while under observation and died despite external ventricular drainage. A 10-year-old boy with previous ventriculoperitoneal (VP) shunt placement underwent conversion to a third ventriculostomy and shunt removal. Eight months after the procedure his condition deteriorated, with evidence of raised ICP, and he underwent emergency insertion of another VP shunt, but remained in a vegetative state and died of complications. Neuropathological examinations in two cases demonstrated that the third ventriculostomy was not patent, and there was also evidence of increased ICP.
Late failure of third ventriculostomy resulting in death is a rare complication. Delay in recognition of recurrent ICP symptoms and a false feeling of security on the part of family and caregivers because of the absence of a shunt and the belief that the hydrocephalus has been cured may contribute to fatal complications after third ventriculostomy. Patients with third ventriculostomies should be followed in a manner similar to patients with cerebrospinal fluid shunts.
Sagun Tuli, Jayshree Tuli, James Drake and Julian Spears
Object. Despite improved therapeutic strategies and better diagnostic techniques in the management of pediatric hydrocephalus there continues to be a significant mortality rate associated with cerebrospinal fluid (CSF) shunts. The goal of this study was to determine the long-term outcome and predictors of death in these patients.
Methods. Data were collected in all patients requiring a CSF shunt presenting to a single tertiary care pediatric institution during a 10-year period. Patients with neoplasms were excluded because their deaths were predominantly related to the tumor. Descriptive statistics were obtained on the patient characteristics, surgical features, and shunt characteristics. The time and cause of death were determined. Kaplan—Meier survival estimates were used to determine overall survival of patients. Univariate analysis was performed using the log-rank test. Multivariate analysis included use of Cox regression model to determine the significance of age (at the time of initial shunt insertion), the number of shunt-related failures and infections, and whether the shunts were complex or multiple in nature in predicting death. Hazard ratios, 95% confidence intervals and probability values were calculated.
Of 907 patients, 124 died. The most common causes were myelomeningocele (191 cases), intraventricular hemorrhage (114 cases), and tumor (190 cases) with 7.9, 3.5, and 32.6% dying, respectively, during the study period. Restricting all analyses to cases without neoplasms, the incidence of shunt-related failures was 58.1% in patients who died and 55.3% in those who survived, with an incidence of shunt-related infection of 19.4% in the former and 18.5% in the latter. The overall mortality rates in all patients at 1, 5, and 10 years were 4.5, 8.9, and 12.4%, respectively, from time of initial shunt insertion to death or last follow-up visit. The infection rate per procedure (that is, following the first shunt insertion) was 10.9% (78 of 717 cases). Evaluation of predictors of death revealed a statistically significant effect of infection with a hazard ratio of 1.66 (p = 0.04).
Conclusions. The mortality rate in shunt-treated pediatric patients with hydrocephalus remains high, dependent on the underlying reason for CSF shunt insertion and the subsequent development of infection of the shunt apparatus.
Paul Klimo Jr., Clinton J. Thompson, James Drake and John R. W. Kestle
Object. Most surgical procedures are associated with a learning curve in which the success rate is lower early in the experience before mistakes have been identified and modifications made to the procedure. Negative results obtained early in a trial's learning curve may be a matter of timing rather than a reflection of the procedure's effectiveness. The recently published results of the Endoscopic Shunt Insertion Trial (ESIT) represent the notion that endoscopically placed shunts were no more likely to survive than conventionally placed shunts. This negative result may be due to inexperience in performing endoscopic surgeries.
Methods. Surgical experience was assessed in two ways. Shunt survival rates were compared between cases treated endoscopically in the 1st and last years of the ESIT. The effect of center volume was evaluated using a Cox proportional hazard model in which the following variables were analyzed: age at registration, the diagnosis of myelomeningocele, head size, method of shunt placement (endoscopic compared with conventional), and center volume.
There was no difference in survival (endurance) of the shunt between patients enrolled in the 1st and last years (log rank = 0.08, p = 0.77). Likewise, no variable in the Cox multivariate model, including center volume, was a significant factor in predicting shunt survival.
Conclusions. The primary result of the ESIT was found to be internally valid. The fact that endoscopic shunt placement did not benefit patients evaluated in the study was not due to early timing of the trial. Any learning curve among the participating surgeons did not adversely affect the results.
James Drake, Paul Chumas, John Kestle, Alain Pierre-Kahn, Matthieu Vinchon, Jennifer Brown, Ian F. Pollack and Hajime Arai
Late rapid deterioration after endoscopic third ventriculostomy (ETV) is a rare complication. The authors previously reported three deaths from three centers. Three other deaths and a patient who experienced rapid deterioration have also been reported. Following the death at the University of Toronto of an additional patient who underwent surgery elsewhere, they canvassed pediatric neurosurgeons in North America, Europe, Australia, and Asia for additional cases.
An email was sent to the members of the Canadian Congress of Neurological Sciences who are pediatric neurosurgeons, to the pediatric neurosurgery email list of the American Association of Neurological Surgeons, to the email list of the International Society for Pediatric Neurosurgery, and to designated neurosurgeons in the United Kingdom, France, Japan, Korea, Taiwan, and Australia, who in turn contacted pediatric neurosurgeons in their countries. A data form was provided, and data from previously reported cases were extracted.
Nine additional cases were identified, and the results were collated with those of the seven cases previously reported. Patient age at surgery ranged from 2 days to 13 years (mean 7.6 years). The most common causes of hydrocephalus were aqueductal stenosis in 50% of patients and tectal glioma in 25% of patients. The time to treatment failure ranged from 5 weeks to 7.8 years (mean 2.5 years). Thirteen patients died, one patient was in a vegetative state, one patient was mildly disabled, and one patient whose condition deteriorated outside the operating room was alive and well. In the 13 patients in whom the ventriculostomy site was visualized at autopsy or repeated endoscopy, the ventriculostomy was shown to be occluded.
Late rapid deterioration is a rare but lethal complication of ETV. The mechanism is unclear, but deterioration can occur long after the ETV becomes occluded. Patients and caregivers should be counseled regarding this potential complication. An indwelling ventricular access device is an option for patients undergoing ETV.
Bart Depreitere, Neermala Dasi, James Rutka, Peter Dirks and James Drake
Endoscopy is a useful technique for obtaining biopsy samples of intraventricular tumors, and it offers the advantage of simultaneous treatment of obstructive hydrocephalus through endoscopic third ventriculostomy (ETV). Figures in the literature on the diagnostic yield of endoscopic biopsy, its complication rate, and the success rate of ETV in this context vary significantly. The authors performed a retrospective analysis of biopsy accuracy, complication rate, and success rate of ETV in a series of 31 endoscopic biopsy procedures.
All data regarding tissue and cerebrospinal fluid sampling, endoscopy-related complications, procedures performed for hydrocephalus treatment, tissue diagnosis, and further management were reviewed. The accuracy of the biopsy findings was graded on a four-level scale: Level I, fully diagnostic; Level II, diagnostic with some reservation; Level III, pathological categorization problematic; and Level IV, not interpretable. Failure of ETV was defined as the need for any further operation for the treatment of hydrocephalus.
Tissue diagnosis was graded as Level I or II in 23 cases. One Level I diagnosis differed from the diagnosis made following craniotomy. During the study period one patient underwent endoscopy without biopsy because the tumor could not be visualized. Consequently, the percentage of successful biopsies was 69% (22 of 32 endoscopic procedures). Complications occurred in six cases (19%), of which two (6%) were significant. Three patients (10%) suffered hemorrhagic complications. When combined with biopsy, the ETV procedure was successful in nine (64%) of 14 patients.
Endoscopic biopsy of intraventricular tumors is a useful technique for establishing a tissue diagnosis and is associated with an acceptable complication rate. The biopsy does not affect the success rate of simultaneous ETV.
Shokei Yamada and Daniel J. Won
Abstract (N. R. Selden)
Controversy exists regarding proper indications for surgical lysis of the terminal filum in children with voiding dysfunction and tethered spinal cord. Recently, surgery has been offered to children who have a normally positioned conus medullaris and no terminal filum abnormality visible on 1.5-tesla magnetic resonance images (referred to as minimal or occult tethered cord syndrome [TCS]). The author evaluates existing clinical and scientific evidence relevant to this controversy.
Five retrospective, observational, noncontrolled studies of surgical terminal filum lysis for occult TCS in children were identified. Two further studies in which the authors reported surgical results in children with a normal-level conus medullaris were also identified.
These studies document encouraging clinical outcomes following surgery. Clinicopathological evidence suggests that occult TCS may result from radiographically occult structural abnormalities of the terminal filum. Although a preponderance of Class III clinical evidence supports the use of surgical filum lysis to treat occult TCS, no Class I or II evidence exists. Clinical practice varies; therefore, performance of a prospective randomized clinical trial of surgical terminal filum lysis for the treatment of occult TCS is advocated.