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  • Author or Editor: John R. W. Kestle x
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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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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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Richard C. E. Anderson, Marion L. Walker, John M. Viner and John R. W. Kestle

✓ Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in which patients have encountered powerful electromagnetic fields such as those involved in magnetic resonance imaging, but the effects of small magnetic fields are not well known. The authors present a case in which a child playing with a collection of commercially available toy magnets altered the pressure setting of an implanted valve and may have caused its permanent malfunction.

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Peter Kan, Marion L. Walker, James M. Drake and John R. W. Kestle

Object

Slit ventricle syndrome (SVS) is a delayed complication of shunt insertion and occurs only in children with slitlike ventricles after shunt placement. Although SVS appears to be related to early shunt placement, its predisposing factors are largely unknown.

Methods

Baseline data in 737 children who had received shunts were obtained from the databases of two previous clinical trials. Ventricular size before shunt placement and at the last routine follow up was measured using the fronto-occipital horn ratio (FOHR). Ventricles with an FOHR less than or equal to 0.2 at follow up were classified as slitlike ventricles. A univariate analysis was performed on data obtained in children with more than 1 year of clinical and radiographic follow up to identify risk factors for developing slitlike ventricles. These results were entered into a multivariate analysis to identify independent predictors of slitlike ventricles.

Two hundred forty-four children had more than 1 year of clinical and radiographic follow-up data. The 23 patients (9.4%) who developed slitlike ventricles had shunts inserted at a younger age (42 compared with 134 days, p = 0.09) and were more likely to have developed hydrocephalus secondary to infection (37.5%), head injury (25.0%), or aqueductal stenosis (22.2%). Slitlike ventricles were seen in 10.8% of patients with differential-pressure valves, 10.5% of patients with Delta valves, and 3.6% of patients with Orbis-Sigma valves (p = 0.007). Regression analysis supported the role of the valve type in developing slitlike ventricles.

Conclusions

Age at shunt insertion and valve type appear to be the modifiable risk factors for developing slitlike ventricles. If the authors of subsequent studies can further validate these conclusions, slow-draining valves and delayed shunt insertion might be used to decrease the incidence of slitlike ventricles and SVS.

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Mandy J. Binning, Brian T. Ragel, Marion L. Walker and John R. W. Kestle

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James K. Liu, Chad D. Cole, Gregory T. Sherr, John R. W. Kestle and Marion L. Walker

✓Extradural arachnoid cysts in the spine are relatively uncommon causes of spinal cord compression in the pediatric population that are thought to arise from congenital defects in the dura mater. Most reports describe such cysts communicating with the intrathecal subarachnoid space through a small defect in the dura. The authors describe the case of a child who presented with spinal cord compression caused by a large spinal extradural arachnoid cyst that did not communicate with the intradural subarachnoid space. An 11-year-old girl presented with urinary urgency, progressive lower-extremity weakness, myelopathy, and severe gait ataxia. Magnetic resonance imaging of the spine demonstrated a large extradural arachnoid cyst extending from T-8 to T-12. The patient underwent a thoracic laminoplasty for en bloc resection of the spinal extradural arachnoid cyst. Intraoperatively, the dura was intact and there was no evidence of communication into the intradural subarachnoid space. Postoperatively, the patient's motor strength and ambulation improved immediately, and no subsequent cerebrospinal fluid leak occurred.

Noncommunicating spinal extradural arachnoid cysts are extremely rare lesions that can cause spinal cord compression in children. Because the dura remains intact, they can be removed entirely without subsequent dural repair. The authors review the literature and discuss the proposed underlying mechanisms of formation of these arachnoid cysts.

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Mandy J. Binning, James K. Liu, John R. W. Kestle, Douglas L. Brockmeyer and Marion L. Walker

✓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.

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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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Hsin-Hung Chen, Jay Riva-Cambrin, Douglas L. Brockmeyer, Marion L. Walker and John R. W. Kestle

Object

In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to the Bio-Glide Snap Shunt ventricular catheters. This prompted a retrospective review of the patient cohort and resulted in a recall by the FDA in the US.

Methods

After the index cases were identified, the FDA was notified by the hospital, leading to a recall of the product. Hospital operative logs were used to identify patients in whom the affected products were used. A letter describing the risk was sent to all patients offering a free screening CT scan to look for disconnection. A call center was established to respond to patient questions, and an informational video was made available on the hospital website. The authors reviewed the records of the index cases and other cases subsequently identified.

Results

Seven index cases and an additional 16 cases of disconnection were identified in the 466 patients in whom a BioGlide Snap Shunt ventricular catheter had been implanted. Mean time to disconnection was 2.7 years (range 4 days–5.8 years). Computed tomography slices in the plane of the catheter helped visualize disconnections. Retrieval was difficult, and in 5 patients the disconnected catheter was not removable. Three catheters were completely within the ventricle. At presentation, 4 children suffered from severe neurological deficits, including one who died as a result of the shunt malfunction.

Conclusions

BioGlide snap-design ventricular catheters are prone to disconnection. Continued vigilance and specific imaging are important. Catheter removal after disconnection may be difficult. Elective removal prior to disconnection in asymptomatic children has not been performed.

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Mandy Binning, Brian Ragel, Douglas L. Brockmeyer, Marion L. Walker and John R. W. Kestle

Object

Childhood radiation exposure increases the lifetime risk of cancer from an estimated 0.07 to 0.35%. Neurological evaluation of patients after cranial vault reconstruction for synostosis repair is often complicated by pain medication, sedation, intubation, swelling, and dressings; therefore computed tomography (CT) scans are routinely ordered by some surgeons on the 1st postoperative day. The object of this study was to evaluate the utility of these scans.

Methods

Medical records and CT scans were reviewed for patients at the authors' institution who underwent cranial vault reconstruction to repair synostosis between January 1, 2003, and July 31, 2005.

Results

Of the 111 patients identified in the review, 84 had a CT scan on postoperative Day 1, and seven of these patients underwent shunt insertion for treatment of hydrocephalus. Thirty-three patients underwent bifrontal craniotomies, whereas 51 underwent total vault reconstruction (TVR). Postoperative CT scans revealed minor contusions in three (9%) of 33 patients in the bifrontal craniotomy group and in seven (14%) of 51 patients in the TVR group. No significant sub-dural or epidural hematomas were observed. In the seven patients who required shunt placement, two (29%) had CT evidence of shunt malfunction, leading to shunt revision.

Conclusions

None of the CT findings analyzed in this series was associated with clinical events such as seizures, prolonged intensive care unit stay, or reoperation in patients without shunt placement after cranial reconstructive procedures, although a relatively high incidence of CT evidence of shunt malfunction was found in patients with shunts. These data do not support the routine use of CT scanning after cranial reconstructive procedures unless the patient has received a shunt for hydrocephalus. Patients who experience unexpected intraoperative or postoperative events should be examined using CT.