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Mark Lee, Ali R. Rezai, Rick Abbott, Daniel H. Coelho and Fred J. Epstein

✓ Spinal cord lipomas are rare lesions, accounting for approximately 1% of all spinal cord tumors. True intramedullary spinal cord lipomas are extremely rare and are represented in the literature as scattered, single case reports. The authors present a series of six patients with intramedullary spinal cord lipomas managed at our institution from July, 1985 to July, 1993. The patients' ages ranged from 8 to 45 years. Four patients presented with newly diagnosed tumors and two had undergone previous surgery. Patients usually presented with long histories of disability followed by rapid progression of their symptoms. Most patients were in poor neurological condition on presentation. Presenting symptoms included spinal pain, dysesthetic sensory changes, gait difficulties, weakness, and incontinence. Three patients had cervical tumors, two had cervicothoracic tumors, and one patient had a thoracic tumor. Diagnostic studies, including magnetic resonance imaging, were obtained in all patients. No patient exhibited any form of spinal dysraphism or had a dural defect. All patients underwent decompressive, subtotal resections of 40% to 70% of their lesions. Follow-up times ranged from 12 to 96 months. All patients had resolution of their pain, but they generally showed no neurological improvement. As of their most recent follow-up visit, none of the patients was neurologically normal; three can function independently, although with neurological deficits. The other three patients cannot function independently and have severe neurological deficits. The authors conclude that patients with intramedullary spinal cord lipoma who present with significant neurological compromise have a very poor prognosis with regard to neurological function and generally show no improvement with surgical resection.

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Ali R. Rezai, Henry H. Woo, Mark Lee, Henry Cohen, David Zagzag and Fred J. Epstein

✓ Ependymomas are rare central nervous system (CNS) neoplasms that occasionally disseminate along the neuraxis or to extraneural sites. Definitive criteria predictive of dissemination have yet to be determined. One hundred forty patients with CNS ependymoma (88 primary spinal and 52 primary intracranial tumors) were surgically treated by the senior author (F.J.E.) between 1986 and 1994. Sixteen patients (11.4%) demonstrated tumor dissemination. The disseminated group consisted of 11 (12.5%) of 88 primary spinal and five (9.6%) of 52 primary intracranial ependymomas. The authors retrospectively reviewed the patients with CNS ependymoma and have identified several characteristics associated with dissemination from the primary tumor site. The mean time from diagnosis to dissemination was 6.8 years. The patients with disseminated disease were younger (16.8 vs. 28.3 years old, p = 0.02), had fewer gross-total resections (29% vs. 68%, p = 0.015), and had tumors with higher proliferative indices (MIB-1 staining, 13.14% vs. 2.06%, p = 0.02). High-grade tumors had a mean proliferation index of 21%, versus 2.4% and 1.6% for myxopapillary and low-grade tumors, respectively (p = 0.0003). In contrast to previous studies, tumor histology was the most significant variable for time to dissemination as determined by multivariate analysis (p = 0.008). Myxopapillary and high-grade tumors were 3.6 and 5.6 times more likely to have a shorter time to dissemination than low-grade tumors. In addition, dissemination is associated with a worse prognosis. At follow-up review, 31% of patients with disseminated disease had died compared to 7% of patients without dissemination (p = 0.04). It is concluded that younger patients with subtotal resections, myxopapillary or high-grade histology, and tumors with high proliferative indices are at substantial risk for the development of disseminated disease during their clinical course.

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Joseph R. Smith, Don W. King, Yong D. Park, Mark R. Lee, Gregory P. Lee and Patrick D. Jenkins

Object. The purpose of this study was to determine if magnetic source (MS) imaging could provide useful information in the planning and performance of gamma knife radiosurgery (GKS) for epilepsy.

Methods. Magnetic source imaging of interictal epileptiform dipoles was studied in 53 epilepsy surgery candidates. All patients underwent volumetric magnetic resonance (MR) imaging. Subsequently, magnetoencephalography (MEG) was performed using single or dual 37—channel units. The MR images and MEG recordings were then coregistered to produce the MS imaging data. Magnetic source imaging epileptiform data were reviewed in a blinded fashion and spatial distributions were classified as focal, regional, multiple, scattered, or none. Postresection operative photographs were compared with MS image results to determine whether extensive or partial/no resection of the MS image focus had been accomplished. Magnetoencephalography dipoles were identified in 47 patients (89%), in 46 of whom the lesions were resected. This included 20 (80%) of 25 anterior temporal lobe (ATL) cases, and 26 (93%) of 28 extratemporal lobe (ETL) cases. Of the six patients who underwent extensive ATL resections, three (50%) were seizure free. Of 14 patients who underwent partial/no resection of the ATL, seven (50%) were seizure free. There was no clear relation between MS image spatial distribution and surgery-related outcome. Of the seven ATL cases with hippocampal atrophy, five patients (71%) were seizure free. Of 12 ETL cases (three lesional), 10 patients (83%) were seizure free. Of 14 patients who underwent partial/no ETL resections (three lesional), two (14%) were seizure free. Of five nonlesional ETL cases with focal MS image dipoles, four patients (80%) were seizure free. Of five nonlesional ETL cases with regional dipoles, three patients (60%) were seizure free. Of eight ETL cases with multiple MS image dipoles, two patients (25%) were seizure free. Spatial agreement of MS imaging and electrographic data had no apparent effect on outcome of either ATL or ETL cases.

Conclusions. Nonlesional ETL cases with focal (and in some cases multiple or regional) epileptiform MS image dipole distributions benefit significantly from inclusion of the MS image epileptiform focus in the resections. Nonlesional ETL cases suitable for GKS may similarly benefit from including the MS image focus in the irradiated area.

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David John Yeh, Richard B. Hessler and Mark R. Lee

Primary leiomyosarcoma of the central nervous system is rare and has been described both de novo and following temporally remote radiotherapy for a different unrelated malignancy. The authors report the case of a 42-year-old man in whom 60Co radiation treatment had been performed for an unknown primary mass in the brainstem 25 years previously. He presented with progressive neurological deterioration after undergoing many years of conservative therapy. A stereotactic biopsy sampling procedure was performed, and examination of the left cerebral pedunculopontine lesion revealed a spindle cell neoplasm. Histopathological and immunohistochemical examination of the tumor obtained from definitive resection suggested leiomyosarcomatous transformation of ganglioglioma.

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Scott Y. Rahimi, E. Andrew Stevens, David John Yeh, Ann Marie Flannery, Haroon Fiaz Choudhri and Mark R. Lee

The atlantoaxial region has been extensively described as a spinal segment especially prone to injury in children. In this clinical review, the authors evaluate and summarize the management of 23 pediatric cases of atlantoaxial instability treated between March 1990 and October 2002. Four broad categories of atlantoaxial problems were observed—atlantoaxial rotatory subluxation in six patients, anterior–posterior atlantoaxial instability caused by ligamentous injury or congenital ligamentous laxity (10 patients), atlantoaxial fracture with or without dislocation (five patients), and atlantooccipital dislocation (two patients). Most cases (60.9%) were treated without surgical intervention, resulting in excellent outcomes; however, 21.7% of cases were treated with a cervical halo (mean patient age 72.6 months) alone for 3 months. Various techniques of surgical stabilization including transarticular screws with sublaminar wiring, trans-oral decompression with posterior plating, and laminectomy with Steinmann pin occipital–cervical fusion were used with good results. Both patients with atlantooccipital dislocation underwent immediate Locksley occipital–cervical fusion, with marked neurological improvement. Individualized case management must be based on clinical presentation, with internal fixation being the last resort.

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Scott Y. Rahimi, Harshpal Singh, David J. Yeh, Ellen G. Shaver, Ann Marie Flannery and Mark R. Lee

Object. Golf-related injuries constitute a common type of sports injury in the pediatric population. The increase in the frequency of these injuries is largely attributed to the increase in the popularity of golf and greater use of golf carts by children.

Methods. The purpose of this study was to investigate the mechanisms and complications associated with golfrelated injuries in the pediatric population and, by doing so, assist in the prevention of such injuries. We reviewed the charts of 2546 pediatric patients evaluated by the neurosurgery service at the authors' institution over a 6-year period. There were 64 cases of sports-related injuries. Of these, 15 (23%) were golf-related, making these injuries the second-largest group of sports-related injuries. Depressed skull fracture was the most common injury observed. Neurosurgical intervention was required in 33% of the cases. With rare exceptions, patients made good recoveries during a mean follow-up period of 22.2 months. One death occurred due to uncontrollable cerebral edema following a golf cart accident. One child required shunt placement and several revisions following an injury sustained from a golf ball.

Conclusions. Children should be advised on the proper use of golf equipment as a preventive measure to avoid these injuries. Precautionary guidelines and safety training guidelines should be established. The institution of a legal minimum age required to operate a golf cart should be considered.

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Scott Y. Rahimi, Harshpal Singh, David J. Yeh, Ellen G. Shaver, Ann Marie Flannery and Mark R. Lee

Object

Golf-related injuries constitute a common type of sports injury in the pediatric population. The increase in the frequency of these injuries is largely attributed to the increase in the popularity of golf and greater use of golf carts by children.

Methods

The purpose of this study was to investigate the mechanisms and complications associated with golfrelated injuries in the pediatric population and, by doing so, assist in the prevention of such injuries. We reviewed the charts of 2546 pediatric patients evaluated by the neurosurgery service at the authors' institution over a 6-year period. There were 64 cases of sports-related injuries. Of these, 15 (23%) were golf-related, making these injuries the second-largest group of sports-related injuries. Depressed skull fracture was the most common injury observed. Neurosurgical intervention was required in 33% of the cases. With rare exceptions, patients made good recoveries during a mean follow-up period of 22.2 months. One death occurred due to uncontrollable cerebral edema following a golf cart accident. One child required shunt placement and several revisions following an injury sustained from a golf ball.

Conclusions

Children should be advised on the proper use of golf equipment as a preventive measure to avoid these injuries. Precautionary guidelines and safety training guidelines should be established. The institution of a legal minimum age required to operate a golf cart should be considered.

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Alan T. Villavicencio, Sigita Burneikiene, E. Lee Nelson, Ketan R. Bulsara, Mark Favors and Jeffrey Thramann

Object. Recombinant human bone morphogenetic protein—2 (rhBMP-2) is being increasingly used for spinal fusion. There are few data regarding its clinical safety, effectiveness, and clinical outcome when applied on an absorbable collagen sponge (ACS) in conjunction with allograft for transforaminal lumbar interbody fusion (TLIF).

Methods. Seventy-four consecutive patients undergoing TLIF for degenerative disc disease were divided into five groups depending on whether the patient underwent a minimally invasive or open approach, as well as the number of spinal levels surgically treated. Surgery-related data, fusion results, complications, and clinical outcome were evaluated. The mean follow-up duration was 20.6 months (range 14–28 months). The radiographic fusion rate was 100% at 12 and 24 months after the surgery. No bone overgrowth or other complications related to BMP use were demonstrated.

Conclusions. Analysis of the results demonstrated that TLIF combined with a BMP-2—soaked ACS is a feasible, effective, and safe method to promote lumbar fusion. There were no significant intergroup differences in clinical outcome between patients who underwent open compared with minimally invasive procedures. Patient satisfaction rates, however, were higher in the minimally invasive procedure group. The efficacy of BMP-2 was not dependent on which approach was used or the number of spinal levels that were treated.

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John R. Vender, Sydney Hester, Jennifer L. Waller, Andy Rekito and Mark R. Lee

Object

Intrathecal baclofen therapy is an effective means of treating intractable spasticity and dystonia in the pediatric and adult population. The authors present a review of complications encountered in a series of 314 pump and catheter-related procedures. The identification and management of these complications will be reviewed. The authors will also identify populations that may be at increased risk for complications.

Methods

A retrospective review was performed of all procedures undertaken during the last 5 years by two surgeons at the authors' institution. Postoperative complications were reviewed.

A total of 314 surgical procedures (226 pediatric and 88 adult) were performed in 195 pediatric and adult patients. This included 171 new pump and catheter implants (116 pediatric and 55 adult), 26 elective pump replacements due to end of battery life (15 pediatric and 11 adult), five elective pump repositionings per physiatrist request (three pediatric and two adult), 14 elective catheter repositionings (10 pediatric and four adult), and two normal pediatric catheter explorations. Surgical procedures for complication management included seven pump revisions (five pediatric and two adult), 48 catheter revisions (38 pediatric and 10 adult), and 41 wound revisions (37 pediatric and four adult). The majority of adult pumps were implanted subdermally, whereas in pediatric patients they were placed subfascially. In general, intrathecal catheters were placed under fluoroscopic guidance with the catheter tip placed at T-1 to T-2 for spastic quadriplegia, T-6 to T-10 for spastic diplegia, and midcervical for dystonia. No significant intraoperative complications were encountered. Overall, there was a statistically significantly higher percentage of procedures for overall complication management and wound complication management in pediatric patients compared with adult patients.

Conclusions

Intrathecal baclofen therapy is a highly effective treatment option for patients with medically refractory spasticity. The catheter, pump, and wound are subject to numerous complications both at the time of implantation and throughout the life of the implanted system. Careful technique, close observation, and aggressive evaluation and correction of problems can reduce the incidence and severity of the complications when they occur.

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Raphael Guzman, Marco Lee, Achal Achrol, Teresa Bell-Stephens, Michael Kelly, Huy M. Do, Michael P. Marks and Gary K. Steinberg

Object

Moyamoya disease (MMD) is a rare cerebrovascular disease mainly described in the Asian literature. To address a lack of data on clinical characteristics and long-term outcomes in the treatment of MMD in North America, the authors analyzed their experience at Stanford University Medical Center. They report on a consecutive series of patients treated for MMD and detail their demographics, clinical characteristics, and long-term surgical outcomes.

Methods

Data obtained in consecutive series of 329 patients with MMD treated microsurgically by the senior author (G.K.S.) between 1991 and 2008 were analyzed. Demographic, clinical, and surgical data were prospectively gathered and neurological outcomes assessed in postoperative follow-up using the modified Rankin Scale. Association of demographic, clinical, and surgical data with postoperative outcome was assessed by chi-square, uni- and multivariate logistic regression, and Kaplan-Meier survival analyses.

Results

The authors treated a total of 233 adult patients undergoing 389 procedures (mean age 39.5 years) and 96 pediatric patients undergoing 168 procedures (mean age 10.1 years). Direct revascularization technique was used in 95.1% of adults and 76.2% of pediatric patients. In 264 patients undergoing 450 procedures (mean follow-up 4.9 years), the surgical morbidity rate was 3.5% and the mortality rate was 0.7% per treated hemisphere. The cumulative 5-year risk of perioperative or subsequent stroke or death was 5.5%. Of the 171 patients presenting with a transient ischemic attack, 91.8% were free of transient ischemic attacks at 1 year or later. Overall, there was a significant improvement in quality of life in the cohort as measured using the modified Rankin Scale (p < 0.0001).

Conclusions

Revascularization surgery in patients with MMD carries a low risk, is effective at preventing future ischemic events, and improves quality of life. Patients in whom symptomatic MMD is diagnosed should be offered revascularization surgery.