Marion L. Walker

Endoscopic Third Ventriculostomy: An Outcome Analysis

Endoscopic third ventriculostomy (ETV) has gained widespread acceptance as an effective way to manage hydrocephalus in selected patients. To determine which patient groups have the highest chance of successful ETV, a retrospective case review was performed. From June 1992 to December 1996, 97 patients underwent a total of 98 ETVs at our institution. There were 59 males and 38 females with a mean age of 8.1 years (range 1 day to 29.5 years). Twenty-six of 98 procedures (26%) were abandoned due to either unfavorable anatomy, inability to perform a cisternostomy, or hemorrhage. Follow-up data was available in 92 patients for a mean of 24.2 months. The rate of successful ETV in 71 patients, with either complete shunt avoidance or removal, varied widely by diagnosis and patient age. The highest success rates were achieved in patients with aqueductal stenosis, tectal plate tumor, myelomeningocele and posterior fossa tumor. Complications included one transient herniation syndrome, one basilar artery perforation, 2 cases of ventriculitis, one transient decrease in level of consciousness, and one transient hemiparesis. We feel these results support the continued use of ETV in only carefully selected patients with hydrocephalus.

The modified injury severity scale in pediatric multiple trauma patients

A Modified Injury Severity Scale (MISS) was devised to classify 110 pediatric patients with multiple trauma. Each of five body areas (neurologic, face and neck, chest, abdomen and pelvic contents, and extremities and pelvic girdle) were ranked by severity according to the carefully-defined categories of the AMA Abbreviated Injury Scale (AIS), with minor modifications. The AIS grades of injury are: 1—mild; 2—moderate; 3—severe, not life-threatening; 4—severe, life-threatening, survival probable, and; 5—critical, survival uncertain. The MISS score is defined as the sum of the squares of the three most-severely injured body areas. Final patient outcomes were ranked as: normal; disabled (some limitation not previously present); dependent (for some activity of daily living), and death. Overall mortality was 14.5% with 9% disability and 0.9% dependency. Both mortality and morbidity correlated linearly with increasing MISS score. Of patients with MISS scores >25, 60% died and 16.7% were either disabled or dependent, while no mortalities and 2.5% disabilities were seen with scores

Real-time image-guided direct convective perfusion of intrinsic brainstem lesions: Technical note

Recent preclinical studies have demonstrated that convection-enhanced delivery (CED) can be used to perfuse the brain and brainstem with therapeutic agents while simultaneously tracking their distribution using coinfusion of a surrogate magnetic resonance (MR) imaging tracer. The authors describe a technique for the successful clinical application of this drug delivery and monitoring paradigm to the brainstem. Two patients with progressive intrinsic brainstem lesions (one with Type 2 Gaucher disease and one with a diffuse pontine glioma) were treated with CED of putative therapeutic agents mixed with Gd-diethylenetriamene pentaacetic acid (DTPA). Both patients underwent frameless stereotactic placement of MR imaging-compatible outer guide-inner infusion cannulae. Using intraoperative MR imaging, accurate cannula placement was confirmed and real-time imaging during infusion clearly demonstrated progressive filling of the targeted region with the drug and Gd-DTPA infusate. Neither patient had clinical or imaging evidence of short- or long-term infusate-related toxicity. Using this technique, CED can be used to safely perfuse targeted regions of diseased brainstem with therapeutic agents. Coinfused imaging surrogate tracers can be used to monitor and control the distribution of therapeutic agents in vivo. Patients with a variety of intrinsic brainstem and other central nervous system disorders may benefit from a similar treatment paradigm.

Optic pathway gliomas: a review

Optic pathway gliomas represent approximately 3-5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11-30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5-7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve.

Complications of Intrathecal Baclofen Pumps in Children

Intrathecal baclofen is increasingly being used to manage severe spasticity in children. Although substantial tone reduction with this treatment has been documented, complications also occur. In this study, we describe the device- and major non-device-related complications in a group of 100 consecutive children and young adults who received 117 intrathecal baclofen pumps for the management of severe spasticity. Twenty-four patients (24%) experienced a total of 48 complications. The most common complication was disconnection of the catheter at its connection to the pump, occurring in 9% of pumps implanted. This complication occurred more frequently in pumps with catheter access ports (16%) than in those without ports (2%). Catheter dislodgement from the intrathecal space was the next most common complication, occurring in 8% of pumps implanted (13% of pumps with ports, 4% of pumps without ports). To decrease the occurrence of the most common complications of intrathecal pumps, we now typically implant pumps without catheter access ports, and we use 2-piece catheters. Although the lack of an access port may be a disadvantage for troubleshooting, most complications can be detected in pumps without a port. Patient and family education is critical in preventing serious consequences of baclofen withdrawal resulting from catheter-related complications.

Basilar Artery Perforation as a Complication of Endoscopic Third Ventriculostomy

The morbidity and mortality associated with third ventriculostomy has decreased significantly over the past 75 years since its introduction by Walter Dandy. Now more commonly performed using an endoscopic method, the significant morbidity of third ventriculostomy has dropped to approximately 5%; essentially that associated with ventriculoscopy in general. However, the possible complication of massive subarachnoid hemorrhage resulting from perforation of the basilar artery or its branches in the course of fenestration of the floor of the third ventricle has only recently been reported. In our case, subsequent to a vascular injury, a pseudoaneurysm developed at the site of vascular perforation, which was then appropriately controlled. The patient has since made a full recovery. Our goal is to remind the endoscopist of this unusual complication and to discuss our management strategies.

A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

OBJECT Quality improvement techniques are being implemented in many areas of medicine. In an effort to reduce the ventriculoperitoneal shunt infection rate, a standardized protocol was developed and implemented at 4 centers of the Hydrocephalus Clinical Research Network (HCRN). METHODS The protocol was developed sequentially by HCRN members using the current literature and prior institutional experience until consensus was obtained. The protocol was prospectively applied at each HCRN center to all children undergoing a shunt insertion or revision procedure. Infections were defined on the basis of CSF, wound, or pseudocyst cultures; wound breakdown; abdominal pseudocyst; or positive blood cultures in the presence of a ventriculoatrial shunt. Procedures and infections were measured before and after protocol implementation. RESULTS Twenty-one surgeons at 4 centers performed 1571 procedures between June 1, 2007, and February 28, 2009. The minimum follow-up was 6 months. The Network infection rate decreased from 8.8% prior to the protocol to 5.7% while using the protocol (p = 0.0028, absolute risk reduction 3.15%, relative risk reduction 36%). Three of 4 centers lowered their infection rate. Shunt surgery after external ventricular drainage (with or without prior infection) had the highest infection rate. Overall protocol compliance was 74.5% and improved over the course of the observation period. Based on logistic regression analysis, the use of BioGlide catheters (odds ratio [OR] 1.91, 95% CI 1.19-3.05; p = 0.007) and the use of antiseptic cream by any members of the surgical team (instead of a formal surgical scrub by all members of the surgical team; OR 4.53, 95% CI 1.43-14.41; p = 0.01) were associated with an increased risk of infection. CONCLUSIONS The standardized protocol for shunt surgery significantly reduced shunt infection across the HCRN. Overall protocol compliance was good. The protocol has established a common baseline within the Network, which will facilitate assessment of new treatments. Identification of factors associated with infection will allow further protocol refinement in the future.

Pediatric cervical spine instrumentation using screw fixation

From July 1986 to August 1993 we performed 24 pediatric cervical spine screw fixation procedures on 23 patients 16 years of age or less. The types of cervical instrumentation procedures performed were as follows: anterior cervical plates 12, posterior C1-2 screw fixations 8, posterior lateral mass plates 2, odontoid screw fixations 2. The mean age of all patients was 14.2 years (range 6-16). Indications for operation included traumatic instability in 20 cases, congenital instability in 1 case, 2 cases of postoperative swan neck deformity, and one reoperation for early graft and hardware failure. Six of the 23 patients had persistent instability following previous failed fusions (3 with 1 prior surgery, 2 with 2 prior surgeries, and 1 with 3 prior surgeries). Eight patients had improvement of their neurological status following operation and 15 remained at their preoperative level of neurological function. No patient was worse neurologically after their procedure. There were no long-term instrumentation, graft or fusion failures. Two complications occurred. One was the aforementioned graft and hardware failure requiring reoperation, the other was a superficial wound infection treated successfully with antibiotics. We feel that cervical spine fixation techniques have increased our ability to stabilize the pediatric cervical spine and have proven to be safe and effective.

Care provider assessment of intrathecal baclofen in children

Intrathecal baclofen is used increasingly to manage severe spasticity in children. Before implanting the baclofen pump, care providers typically ask how it will benefit their child. The purpose of this study was to describe the perceptions of care providers about intrathecal baclofen for management of spasticity in 80 individuals (52 males, 28 females). The individuals were younger than 22 years at the time of implantation (mean age 11 years, SD 5 years; range 3 to 21 years). Participants had been implanted with the pump for a minimum of one year at the time of evaluation. The most common diagnoses were quadriplegic and diplegic cerebral palsy and traumatic brain injury. Most participants were at level IV and V on the Gross Motor Function Classification System. After pump implantation most participants had tone reduction on the Ashworth scale of 1 to 1.9 in the lower extremities and 0 to 0.9 in the upper extremities. Lower extremity range of motion was maintained in 43 of 51 individuals (84%) and lost in 8 participants (16%). Complications requiring surgery occurred in 63 of a larger group of 152 patients (incidence per patient-year of follow-up was 0.19). Thirty-one of the 80 children had orthopedic procedures after pump placement. Only one of these was unexpected and none had rapid progression of scoliosis. Most treatment goals were achieved. Goals most commonly chosen (decreased pain, prevention of worsening of deformity, and improved ease of care) were improved in 91%, 91%, and 88% of participants respectively. Ninety-five per cent of care providers agreed that they would have this procedure performed again (81% strongly agreed, 14% slightly agreed). All care providers reported improvement in scores on the Caregiver Questionnaire. This information has been helpful to families considering intrathecal baclofen therapy.

Genetic studies in neural tube defects

Neural tube defects (NTD) are one of the most common birth defects and are caused by both environmental and genetic factors. The approach to identifying the genes predisposing to NTD, through linkage analysis and candidate gene analysis, is reviewed along with characteristics of a large, nationally ascertained cohort of families. Results from specific assessments of p53, PAX3 and MTHFR failed to suggest that these genes play a major role in NTD development in these families. Advances in genetic laboratory and statistical techniques have made this a prime opportunity for investigation into the causes of complex disorders, such as NTD. However, traditional approaches may prove to be challenging due to the difficulty of ascertaining samplable multiplex families.