✓ Between 4% and 8% of cases of spina bifida cystica occur in a cervical or cervicothoracic location. Despite a large body of literature concerning spinal dysraphism, there has been little written specifically about patients afflicted with this disorder in a cervical location. Eight children who presented at birth with posterior cervical or cervicothoracic lumps, all of which represented a dysraphic state, are discussed. Two types of abnormalities were noted. Three patients had hydromyelia with an associated myelocystocele herniating posteriorly into a meningocele sac. In these three patients there was an associated Chiari II malformation and hydrocephalus. The other five children had a meningocele in which a band of tissue extended from the posterior aspect of the spinal cord through a defect in the bone and fascia to the posterior part of the meningocele sac itself. No patient had a lesion that could be described as a meningomyelocele. The investigation and surgical management of these conditions are discussed and the need for intradural exploration to untether the spinal cord in the cervical region is stressed.
Paul Steinbok and D. Douglas Cochrane
Paul Steinbok, Robert Keyes, Lisa Langill, and D. Douglas Cochrane
✓ Although selective functional posterior rhizotomy (SFPR) is an established procedure for the treatment of spasticity, the electrophysiological criteria used to define which posterior rootlets should be cut have not been standardized. The purpose of this study was to determine the validity of the intraoperative electrophysiological criteria used to select posterior rootlets for sectioning in SFPR.
Intraoperative stimulation of posterior lumbosacral nerve roots and rootlets, using a 50-Hz stimulus at threshold intensity, was performed in five nonspastic children (controls) undergoing laminectomy for spinal cord untethering and in 32 spastic patients undergoing SFPR. Electromyographic responses were recorded in the upper and lower limbs, the neck, and the face. The pattern of sustained responses was assessed in detail in 17 additional patients who had previously undergone SFPR and in the five controls. Sustained responses with ipsilateral lower limb extrasegmental spread occurred in both spastic patients and the control group. Contralateral lower limb spread and suprasegmental spread to the upper limbs, neck, and face were found only in spastic children. Sustained responses with an incremental pattern were restricted to the spastic population and correlated well with the extent of contralateral and suprasegmental spread, whereas decremental patterns were not associated with contralateral spread.
It is concluded that contralateral and suprasegmental spread into the upper limbs, neck, and face, and incremental responses are probably valid criteria of abnormality.
Paul Steinbok, D. Douglas Cochrane, and John R. W. Kestle
✓ The purpose of this study was to determine the significance of “asymptomatic bacteriological shunt contamination” (ABSC), defined as a positive bacteriological culture found on a ventricular shunt component in the absence of bacteria in the cerebrospinal fluid (CSF) culture and/or clinical evidence of infection.
Of 174 ventriculoperitoneal shunt revisions, 19 cases of ABSC were identified and reviewed retrospectively. In all but one case, no antibiotic medications were instituted because of the positive bacteriological culture. The most common infecting organisms were coagulase-negative staphylococci (seven) and propionibacteria (eight). A comparison of the 19 study cases with the authors' overall shunt experience, as documented in the British Columbia's Children's Hospital shunt database for the time period of the study, lead the authors to suggest that ABSC was not of significance in causing the shunt failure at which contamination was identified and, more importantly, did not increase the risk of future shunt malfunction.
The results of this study indicate that in the absence of clinical evidence of shunt infection or a positive bacteriological culture from CSF, bacteria in a shunt component removed at revision in a child almost always represents a contaminant that may be ignored. Therefore, the authors advise that routine culture of shunt components removed at revision of a shunt is not indicated.
Paul Steinbok, Stephen Hentschel, D. Douglas Cochrane, and John R. W. Kestle
✓ The rationale for obtaining surveillance computerized tomography (CT) scans or magnetic resonance (MR) images in pediatric patients with brain tumors is that early detection of recurrence may result in timely treatment and better outcome. The purpose of this study was to investigate the value of surveillance cranial images in a variety of common pediatric brain tumors managed at a tertiary care pediatric hospital.
A retrospective chart review was performed of children with astrocytoma of the cerebral hemisphere, cerebellum, optic chiasm/hypothalamus, or thalamus; cerebellar or supratentorial high-grade glioma; supratentorial ganglioglioma; posterior fossa or supratentorial primitive neuroectodermal tumor (PNET); and posterior fossa ependymoma. Data were analyzed to determine the frequency with which recurrences were identified on a surveillance image and how the type of image at which recurrence was identified related to outcome.
In 159 children, 17 of 44 recurrences were diagnosed by surveillance imaging. The percentage of recurrences identified by surveillance imaging was 64% for ependymoma, 50% for supratentorial PNET, 43% for optic/hypothalamic astrocytoma, and less than 30% for other tumors. The rate of diagnosis of recurrence per surveillance image varied from 0% to 11.8% for different tumor types. Only for ependymomas did there appear to be an improved outcome when recurrence was identified prior to symptoms.
Our results indicate that, using the protocols outlined in this study, surveillance imaging was not valuable in identifying recurrence of cerebellar astrocytoma or supratentorial ganglioglioma during the study period, but was probably worth-while in identifying recurrence of posterior fossa ependymoma and optic/hypothalamic astrocytoma and, possibly, medulloblastoma. Surveillance protocols could be made more effective by individualizing them for each type of tumor, based on current data on the patterns of recurrence.
Robert W. Armstrong, Paul Steinbok, D. Douglas Cochrane, Susan D. Kube, Susan E. Fife, and Kevin Farrell
✓ Management of severe spasticity in children is often a difficult problem. Orally administered medications generally offer limited benefits. This study examines the value of intrathecally administered baclofen in the treatment of 19 children with severe spasticity of cerebral origin: eight of whom sustained brain injury associated with trauma, near drowning, or cardiac arrest; 10 with cerebral palsy (spastic quadriplegia); and one child with Leigh's disease. At the time of entry into the study, patients ranged from 4 to 19 years of age, and all were completely dependent on caretakers for activities of daily living.
Children who responded positively to a trial dose of intrathecal baclofen underwent insertion of a drug delivery system for continuous infusion. This was followed by a double-blind trial of baclofen or placebo and follow-up review at 3 and 6 months, and yearly thereafter. Seven children did not undergo pump implantation because of excess sedation or poor response. The 12 remaining children have been followed for a period of 1 to 5 years. Favorable responses were present in all 12 children as determined by the Ashworth Scale, with the greatest benefit being reduction of lower limb tone. Except in the case of one child who had reduction in lower limb tone that resulted in difficulty with transfers, the caretakers all reported significant benefits from intrathecal baclofen, with improvement in muscle tone, behavior, sitting, and general ease of care being most commonly noted.
Central side effects were seen in some children who received continuous intrathecal baclofen infusion and included hypotension (two patients), bradycardia (two), apnea or respiratory depression (two), and sedation (one). During a total of 568 months of pump operation there were 10 mechanical complications, including two related to pump or side port failure and eight related to catheter kinks, extrusions, or dislodgment. Pump pocket effusion occurred in five children and a cerebrospinal fluid fistula was seen in one child. Local infection occurred in three children and meningitis in two children.
The results demonstrate the potential value of continuous intrathecal baclofen infusion for treatment of severe spasticity of cerebral origin. However, this treatment can result in significant complications and more experience is required before the long-term benefits can be determined.
John C. L. Sun, Paul Steinbok, and D. Douglas Cochrane
✓ The spontaneous resolution of syringomyelia has been reported infrequently. In patients with Chiari I malformations, resolution of the syringomyelia has sometimes been associated with improvement of their malformation. The authors present a case of spontaneous resolution followed by recurrence of syringomyelia and a corresponding change in the Chiari malformation. This case is of interest in light of the theories postulated to explain spontaneous resolution of syringomyelia.
Stephen Hentschel, Paul Steinbok, D. Douglas Cochrane, and John Kestle
Object. As public concern about the risks of blood transfusions increased in the mid-1990s, avoidance of transfusions became a goal of surgery for sagittal synostosis. This study was performed to confirm a hypothesized reduction in transfusion rates in recent years and to identify factors associated with both the need for transfusion and low postoperative levels of hemoglobin.
Methods. Sagittal synostosis operations performed in children between 1986 and 1999 were reviewed retrospectively. Patients underwent a minimum of vertex strip craniectomy and parietal craniectomies. There were 118 patients whose median age at surgery was 4.2 months. The primary end point for analysis was defined as either the receipt of a blood transfusion or a postoperative level of hemoglobin less than 70 g/L. Forty-two percent of patients (95% confidence interval [CI] 31–52%) treated before 1996 and 11% of patients (95% CI 0–23%) treated from 1996 onward received blood. The reduction in the blood transfusion rate in later years was, in part, related to the acceptance of a lower postoperative hemoglobin level, often below 70 g/L. A univariate analysis showed that the only patient or surgical factors that correlated with reaching the primary end point in a statistically significant manner were the year of surgery and the extent of surgery. A logistic regression of the age and weight of the child, length of surgery time (from skin opening to skin closure), preoperative hemoglobin level, extent of surgery, and surgeon against the primary end point revealed that the best predictor of the need for a blood transfusion or the presence of a postoperative hemoglobin level lower than 70 g/L was the extent of surgery (β = 1.4, standard error of the β statistic = 0.44). Once the extent of surgery was accounted for in the model, no other covariates significantly improved the model.
Techniques implemented to minimize blood loss since 1995 included the following: use of the Colorado needle for scalp incision, selection of the Midas Rex craniotome for cranial cuts, and application of microfibrillar collagen. Postoperative hemoglobin was allowed to decrease to 60 g/L if the child was stable hemodynamically, before blood was administered. There were no cardiovascular, wound healing, or infectious complications, and no surgeries were repeated for cosmetic reasons.
Conclusions. Low blood transfusion rates were achieved using simple intraoperative techniques and by accepting a low level of postoperative hemoglobin.
John R. W. Kestle, James M. Drake, D. Douglas Cochrane, Ruth Milner, Marion L. Walker, Rick Abbott III, Frederick A. Boop, and the Endoscopic Shunt Insertion Trial Participants
Object. Endoscopically assisted ventricular catheter placement has been reported to reduce shunt failure in uncontrolled series. The authors investigated the efficacy of this procedure in a prospective multicenter randomized trial.
Methods. Children younger than 18 years old who were scheduled for their first ventriculoperitoneal (VP) shunt placement were randomized to undergo endoscopic or nonendoscopic insertion of a ventricular catheter. Eligibility and primary outcome (shunt failure) were decided in a blinded fashion. An intention-to-treat analysis was performed. The sample size offered 80% power to detect a 10 to 15% absolute reduction in the 1-year shunt failure rate.
The authors studied 393 patients from 16 pediatric neurosurgery centers between May 1996 and November 1999. Median patient age at shunt insertion was 89 days. The baseline characteristics of patients within each group were similar: 54% of patients treated with endoscopy were male and 55% of patients treated without endoscopy were male; 30% of patients treated with and 26% of those without endoscopy had myelomeningocele; a differential pressure valve was used in 51% of patients with and 49% of those treated without endoscopy; a Delta valve was inserted in 38% of patients in each group; and a Sigma valve was placed in 9% of patients treated with and 12% of those treated without endoscopy. Median surgical time lasted 40 minutes in the group treated with and 35 minutes in the group treated without endoscopy. Ventricular catheters, which during surgery were thought to be situated away from the choroid plexus, were demonstrated to be in it on postoperative imaging in 67% of patients who had undergone endoscopic insertion and 61% of those who had undergone nonendoscopic shunt placements. The incidence of shunt failure at 1 year was 42% in the endoscopic insertion group and 34% in the nonendoscopic group. The time to first shunt failure was not different between the two groups (log rank = 2.92, p = 0.09).
Conclusions. Endoscopic insertion of the initial VP shunt in children suffering from hydrocephalus did not reduce the incidence of shunt failure.