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Marion L Walker

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Michael A. Finn and Marion L. Walker

✓Spinal lipomas, particularly lipomas of the conus medullaris and terminal filum, are the most common form of occult spinal dysraphism and represent a wide spectrum of disease with regard to anatomy, clinical presentation, and treatment options. These lesions, however, are united by a similar embryology and pathological mechanism by which symptoms arise.

Recently, the treatment of these lesions has generated much controversy, with some physicians advocating surgical treatment for all patients regardless of symptoms and others proposing that surgery be withheld until symptoms develop. The authors discuss lumbosacral spinal lipomas, with particular attention to the theories of their origin, anatomical and pathological features, and treatment options, including a review of current controversies.

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James K. Liu and Marion L. Walker

P Intrathecal baclofen pumps for the management of severe spasticity are being used more often in children with cerebral palsy. The intrathecal catheter is traditionally introduced dorsally in the lumbar region. In some children with previous thoracolumbar fusions for scoliosis, the fusion mass obviates the introduction of the intrathecal catheter.

The authors describe their experience with a posterior cervical approach for intrathecal baclofen pump insertion in three patients with spastic quadriplegic cerebral palsy who had previously undergone thoracolumbar fusions for scoliosis. Insertion was successful in all three patients; no complications of catheter disconnection, catheter dislodgment, or cerebrospinal fluid leakage occurred. Follow-up review ranged from 10 to 28 months postoperatively (mean 17 months). The posterior cervical approach for intrathecal baclofen pump insertion is a safe and effective alternative for patients who have previously undergone thoracolumbar spine fusions and in whom the traditional lumbar approach is not feasible.

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John R. W. Kestle and Marion L. Walker

Object. Previous reports suggest that adjustable valves may improve the survival of cerebrospinal fluid shunts or relieve shunt-related symptoms. To evaluate these claims, the authors conducted a prospective multicenter cohort study of children who underwent placement of Strata valves.

Methods. Patients undergoing initial shunt placement (Group 1) or shunt revision (Group 2) were treated using Strata valve shunt systems. Valves were adjustable to five performance level settings by using an externally applied magnet. The performance levels were checked using an externally applied hand tool and radiography. Patients were followed for 1 year or until they underwent shunt revision surgery.

Between March 2000 and February 2002, 315 patients were enrolled in the study. In Group 1 (201 patients) the common causes of hydrocephalus were myelomeningocele (16%), aqueductal stenosis (14%), and hemorrhage (14%). The overall 1-year shunt survival was 67%. Causes of shunt failure were obstruction (17%), overdrainage (1.5%), loculated ventricles (2%), and infection (10.6%). Patients in Group 2 (114 patients) were older and the causes of hydrocephalus were similar. Among patients in Group 2 the 1-year shunt survival was 71%.

There were 256 valve adjustments. Symptoms completely resolved (26%) or improved (37%) after 63% of adjustments. When symptoms improved or resolved, they did so within 24 hours in 89% of adjustments. Hand-tool and radiographic readings of valve settings were the same in 234 (98%) of 238 assessments.

Conclusions. The 1-year shunt survival for the Strata valve shunt system when used in initial shunt insertion procedures or shunt revisions was similar to those demonstrated for other valves. Symptom relief or improvement following adjustment was observed in 63% of patients. Hand-tool assessment of performance level settings reliably predicted radiographic assessments.

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Robert J. Bollo, Judith L. Gooch and Marion L. Walker

Continuous infusion of baclofen is a treatment option for severe generalized dystonia. Catheter insertion within the third ventricle has been described as an alternative to standard intrathecal placement to maximize intracranial concentrations of baclofen. The authors describe their experience with a novel technique for stereotactic endoscopic insertion of baclofen infusion catheters in the third ventricle in 3 patients with severe secondary generalized dystonia. Insertion was successful in all 3 patients, and all of them experienced significant improvement in dystonia scores on the Barry-Albright Dystonia Scale. Follow-up ranged from 5.5 to 7 months (mean 6 months), and no mechanical complications or CSF leaks were observed. The stereotactic endoscopic insertion of a baclofen infusion catheter into the third ventricle appears to be a safe method for continuous intraventricular baclofen infusion in patients with generalized secondary dystonia.

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John R. W. Kestle and Marion L. Walker

Object

Previous reports suggest that adjustable valves may improve the survival of cerebrospinal fluid shunts or relieve shunt-related symptoms. To evaluate these claims, the authors conducted a prospective multicenter cohort study of children who underwent placement of Strata valves.

Methods

Patients undergoing initial shunt placement (Group 1) or shunt revision (Group 2) were treated using Strata valve shunt systems. Valves were adjustable to five performance level settings by using an externally applied magnet. The performance levels were checked using an externally applied hand tool and radiography. Patients were followed for 1 year or until they underwent shunt revision surgery.

Between March 2000 and February 2002, 315 patients were enrolled in the study. In Group 1 (201 patients) the common causes of hydrocephalus were myelomeningocele (16%), aqueductal stenosis (14%), and hemorrhage (14%). The overall 1-year shunt survival was 67%. Causes of shunt failure were obstruction (17%), overdrainage (1.5%), loculated ventricles (2%), and infection (10.6%). Patients in Group 2 (114 patients) were older and the causes of hydrocephalus were similar. Among patients in Group 2 the 1-year shunt survival was 71%.

There were 256 valve adjustments. Symptoms completely resolved (26%) or improved (37%) after 63% of adjustments. When symptoms improved or resolved, they did so within 24 hours in 89% of adjustments. Hand-tool and radiographic readings of valve settings were the same in 234 (98%) of 238 assessments.

Conclusions

The 1-year shunt survival for the Strata valve shunt system when used in initial shunt insertion procedures or shunt revisions was similar to those demonstrated for other valves. Symptom relief or improvement following adjustment was observed in 63% of patients. Hand-tool assessment of performance level settings reliably predicted radiographic assessments.

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Oren N. Gottfried, Gary L. Hedlund, John M. Opitz and Marion L. Walker

Object

The FG syndrome (FGS) is a common, heterogeneous group of clinically indistinguishable X-linked disorders comprising congenital hypotonia, macrocephaly, psychomotor delay, abnormalities in sensory integration, agenesis of corpus callosum, an unusual personality with behavior abnormalities, and disturbances of gastrointestinal function. On magnetic resonance (MR) imaging, some patients have evidence of tonsillar ectopia. The authors describe the incidence of Chiari I malformation in patients with FGS and attempt to determine the optimal treatment of these patients.

Methods

The authors performed a retrospective chart and radiological review of 144 pediatric patients with FGS for evidence of tonsillar ectopia on brain MR imaging. Eleven (7.6%) of these 144 patients had tonsillar ectopia, and in eight patients (5.6%), the tonsils were located more than 5 mm below the foramen magnum. Four of these patients underwent posterior fossa decompression, and surgery was performed at a mean age of 3 years. Indications for surgery included significant headaches and behavioral problems in two patients and failure to thrive with severe breathing and feeding difficulties in two infants. All four improved after surgery. The other patients remained asymptomatic from their tonsillar ectopia, showed no clinical or radiological signs of progression, and did not require surgery.

Conclusions

Chiari I malformation is more common in individuals with FGS than in the general population. Some of these patients with FGS require decompression surgery, but the decision to operate can be difficult because of their developmental delay, difficulties with language skills, general fatigue, possibility of upper motor neuron dysfunction, behavioral problems, or failure to thrive, which may mask the symptoms of a Chiari I malformation.

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John Kestle, Jeannette J. Townsend, Douglas L. Brockmeyer and Marion L. Walker

Object. In reports involving the operative treatment of brainstem tumors, multiple histological types are often grouped together. To determine prognosis after resection, histology-specific data may be helpful.

Methods. Twenty-eight patients with juvenile pilocytic astrocytoma (JPA) of the brainstem (six in the midbrain, four in the pons, and 18 in the medulla) were identified from the medical records. Initial treatment was resection in 25 and biopsy sampling in three. Postoperative imaging revealed gross-total resection (GTR) or resection with linear enhancement (RLE) in 12 of 25 patients and solid residual tumor in the other 13.

In 10 of the 13 patients harboring solid residual tumor, observation was undertaken; the residual lesion disappeared in one, was stable in four, and progressed in five. Of the 12 patients with complete excision or RLE only, seven underwent no further treatment, with tumor progression occurring in one. All patients were alive at last follow-up examination (range 0.3–20.4 years, mean 6 years). New neurological deficits commonly appeared immediately after resection but often resolved. In six of the 28 patients, the new postoperative deficit was still present at last follow-up visit. The 5- and 10-year progression-free survival was 74 and 62%, respectively, after GTR or RLE and 19 and 19%, respectively, when solid residual tumor was present.

Conclusions. Long-term survival after resection of JPAs of the brainstem has been observed and appears to be related to the extent of initial excision.

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James K. Liu, Chad D. Cole, John R. W. Kestle, Douglas L. Brockmeyer and Marion L. Walker

The optimal treatment of craniopharyngioma in children remains a challenge. The use of complete excision to minimize recurrence continues to be controversial because of the risk of postoperative morbidity and death. Advances in skull base approaches, modern microsurgical techniques, neuroimaging, and hormone replacement therapy, however, have allowed safe gross- or near-total resection in the majority of cases. Total removal of these tumors, if possible, offers the best chance of cure for the patient. Although craniopharyngiomas are not strictly tumors of skull base origin, their intimate relationship with the neurovascular structures of this region often requires a skull base approach to maximize the surgical corridor and facilitate adequate microsurgical resection. In this review, the authors focus on commonly used skull base approaches for the surgical management of craniopharyngioma. They discuss the relative indications, advantages, disadvantages, and complications associated with each approach. Illustrative cases and intra-operative videos are presented.

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Christian A. Bowers, Jay Riva-Cambrin, Dean A. Hertzler II and Marion L. Walker

Object

Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the native bone flap, is often used for pediatric patients with traumatic brain injury (TBI) who have a mass lesion and intractable intracranial hypertension. Bone flap resorption is common after bone flap replacement, necessitating additional surgery. The authors reviewed their large database of pediatric patients with TBI who underwent decompressive craniectomy followed by bone flap replacement to determine the rate of bone flap resorption and identify associated risk factors.

Methods

A retrospective cohort chart review was performed to identify long-term survivors who underwent decompressive craniectomy for severe TBI with bone flap replacement from January 1, 1996, to December 31, 2011. The risk factors investigated in a univariate statistical analysis were age, sex, underlying parenchymal contusion, Glasgow Coma Scale score on arrival, comminuted skull fracture, posttraumatic hydrocephalus, bone flap wound infection, and freezer time (the amount of time the bone flap was stored in the freezer before replacement). A multivariate logistic regression model was then used to determine which of these were independent risk factors for bone flap resorption.

Results

Bone flap replacement was performed at an average of 2.1 months after decompressive craniectomy. Of the 54 patients identified (35 boys, 19 girls; mean age 6.2 years), 27 (50.0%) experienced bone flap resorption after an average of 4.8 months. Underlying parenchymal contusion, comminuted skull fracture, age ≤ 2.5 years, and posttraumatic hydrocephalus were significant, or nearly significant, on univariate analysis. Multivariate analysis identified underlying contusion (p = 0.004, OR 34.4, 95% CI 3.0–392.7), comminuted skull fractures (p = 0.046, OR 8.5, 95% CI 1.0–69.6), posttraumatic hydrocephalus (p = 0.005, OR 35.9, 95% CI 2.9–436.6), and age ≤ 2.5 years old (p = 0.01, OR 23.1, 95% CI 2.1–257.7) as independent risk factors for bone flap resorption.

Conclusions

After decompressive craniectomy for pediatric TBI, half of the patients (50%) who underwent bone flap replacement experienced resorption. Multivariate analysis indicated young age (≤ 2.5 years), hydrocephalus, underlying contusion as opposed to a hemispheric acute subdural hematoma, and a comminuted skull fracture were all independent risk factors for bone flap resorption. Freezer time was not found to be associated with bone flap resorption.