Intramedullary tumoral calcinosis

Tumoral calcinosis (TC), a calcium hydroxyapatite-based mass, is common in the extremities and hips, but has rarely been reported in the spine, and has never been reported within the spinal cord. It may occur sporadically, in familial form, or as a consequence of disorders that promote soft-tissue calcification. Gross-total resection appears to be curative, but the diagnosis of TC is rarely considered prior to surgery. In this report, the authors describe the management of the first case of intramedullary TC located at the T-5 level in a 20-month-old boy who presented with lower-extremity spasticity. Additionally, salient features of the TC diagnosis, radiological patterns, histological findings, treatment, and outcomes are discussed.

A computed tomography-based feasibility study of translaminar screw fixation in the upper thoracic spine

OBJECT

Translaminar screws (TLSs) offer an alternative to pedicle screw (PS) fixation in the upper thoracic spine. Although cadaveric studies have described the anatomy of the laminae and pedicles at T1-2, CT imaging is the modality of choice for presurgical planning. In this study, the goal was to determine the diameter, maximal screw length, and optimal screw trajectory for TLS placement at T1-2, and to compare this information to PS placement in the upper thoracic spine as determined by CT evaluation.

METHODS

One hundred patients (50 men and 50 women), whose average age was 41.7 +/- 19.6 years, were selected by retrospective review of a trauma registry database over a 6-month period. Patients were included in the study if they were over the age of 18, had standardized axial bone-window CT imaging at T1-2, and had no evidence of spinal trauma. For each lamina and pedicle, width (outer cortical and cancellous), maximal screw length, and optimal screw trajectory were measured using eFilm Lite software. Statistical analysis was performed using the Student t-test.

RESULTS

The T-1 lamina was estimated to accommodate, on average, a 5.8-mm longer screw than the T-2 lamina (p < 0.001). At T-1, the maximal TLS length was similar to PS length (TLS: 33.4 +/- 3.6 mm, PS: 33.9 +/- 3.3 mm [p = 0.148]), whereas at T-2, the maximal PS length was significantly greater than the TLS length (TLS: 27.6 +/- 3.1 mm, PS: 35.3 +/- 3.5 mm [p < 0.001]). When the lamina outer cortical and cancellous width was compared between T-1 and T-2, the lamina at T-2 was, on average, 0.3 mm wider than at T-1 (p = 0.007 and p = 0.003, respectively). In comparison with the corresponding pedicle, the mean outer cortical pedicle width at T-1 was wider than the lamina by an average of 1.0 mm (lamina: 6.6 +/- 1.1 mm, pedicle: 7.6 +/- 1.3 mm [p < 0.001]). At T-2, however, outer cortical lamina width was wider than the corresponding pedicle by an average of 0.6 mm (lamina: 6.9 +/- 1.1 mm, pedicle: 6.3 +/- 1.2 mm [p < 0.001]). At T-1, 97.5% of laminae measured could accept a 4.0-mm screw with 1.0 mm of clearance, compared with 99.5% of T-1 pedicles; whereas at T-2, 99% of laminae met this requirement, compared with 94.5% of pedicles. The ideal screw trajectory was also measured (T-1: 49.2 +/- 3.7 degrees for TLS and 32.8 +/- 3.8 degrees for PS; T-2: 51.1 +/- 3.5 degrees for TLS and 20.5 +/- 4.4 degrees for PS).

CONCLUSIONS

Based on CT evaluation, there are no anatomical limitations to the placement of TLSs compared with PSs at T1-2. Differences were noted, however, in lamina length and width between T-1 and T-2 that must be considered when placing TLS at these levels.

Precision of navigated stereotactic probe implantation into the brainstem

OBJECT

The indications for stereotactic biopsies or implantation of probes for local chemotherapy in diffuse brainstem tumors have recently come under debate. The quality of performing these procedures significantly depends on the precision of the probes' placement in the brainstem. The authors evaluated the precision of brainstem probe positioning using a navigated frameless stereotactic system in an experimental setting.

METHODS

Using the VarioGuide stereotactic system, 33 probes were placed into a specially designed model filled with agarose. In a second experimental series, 8 anatomical specimens were implanted with a total of 32 catheters into the pontine brainstem using either a suboccipital or a precoronal entry point. Before intervention in both experimental settings, a thin-sliced CT scan for planning was obtained and fused to volumetric T1-weighted MR imaging data. After the probe positioning procedures, another CT scan and an MR image were obtained to compare the course of the catheters versus the planned trajectory. The deviation between the planned and the actual locations was measured to evaluate the precision of the navigated intervention.

RESULTS

Using the VarioGuide system, mean total target deviations of 2.8 +/- 1.2 mm on CT scanning and 3.1 +/- 1.2 mm on MR imaging were detected with a mean catheter length of 151 +/- 6.1 mm in the agarose model. The catheter placement in the anatomical specimens revealed mean total deviations of 1.95 +/- 0.6 mm on CT scanning and 1.8 +/- 0.7 mm on MR imaging for the suboccipital approach and a mean catheter length of 59.5 +/- 4.1 mm. For the precoronal approach, deviations of 2.2 +/- 1.2 mm on CT scanning and 2.1 +/- 1.1 mm on MR imaging were measured (mean catheter length 85.9 +/- 4.7 mm).

CONCLUSIONS

The system-based deviation of frameless stereotaxy using the VarioGuide system reveals good probe placement in deep-seated locations such as the brainstem. Therefore, the authors believe that the system can be accurately used to conduct biopsies and place probes in patients with brainstem lesions.

Hospital costs associated with shunt infections in patients receiving antibiotic-impregnated shunt catheters versus standard shunt catheters

BACKGROUND

The average hospital cost for shunt infection treatment is $50,000, making it the most financially costly implant-related infection in the United States. We set out to determine whether introduction of antibiotic-impregnated shunts (AISs) in our practice has decreased the incidence of shunt infection or decreased infection-related hospital costs at our institution.

METHODS

Clinical and hospital billing records of pediatric patients undergoing cerebrospinal fluid (CSF) shunt insertion at a single institution from April 2001 to December 2006 were retrospectively reviewed. Eighteen months before October 2002, all CSF shunts included standard, non-AIS catheters. During the 4 years after October 2002, all CSF shunts included AIS catheters. Patients were followed at least 18 months after surgery.

RESULTS

A total of 406 pediatric patients underwent 608 shunt placement procedures (400 AISs, 208 non-AISs). Of patients with non-AIS catheters, 25 (12%) experienced shunt infection, whereas only 13 patients (3.2%) with AIS catheters experienced shunt infection during follow-up (P < .001). The total hospital cost to treat 25 non-AIS shunt infections over the first 18 months was $1,234,928. The total hospital cost to treat 13 AIS shunt infections over the past 4 years was $606,328. The mean hospital cost per shunt infection was similar for infected AIS and non-AIS catheters ($46,640 vs. $49,397). However, the infection-related hospital cost per 100 patients shunted was markedly lower in the AIS cohort than in the non-AIS cohort ($151,582 vs. $593,715).

DISCUSSION

The introduction of AIS catheters in our institutional practice reduced the incidence of shunt infection and resulted in significant hospital cost savings. AIS systems are efficient and cost-effective instruments to prevent perioperative colonization of CSF shunt components.

The evolution of intramedullary spinal cord tumor surgery

OBJECTIVE

Resections of intramedullary spinal cord tumors were attempted as early as 1890. More than a century after these primitive efforts, profound advancements in imaging, instrumentation, and operative techniques have greatly improved the modern surgeon's ability to treat such lesions successfully, often with curative results.

METHODS

We review the history of intramedullary spinal cord tumor surgery, as well as the evolution and advancement of technologies and surgical techniques that have defined the procedure over the past 100 years.

RESULTS

Surgery to remove intramedullary spinal cord tumors has evolved to include sophisticated imaging equipment to pinpoint tumor location, laser scalpel systems to provide precise incisions with minimal damage to surrounding tissue, and physiological monitoring to detect and prevent intraoperative motor deficits.

CONCLUSION

Modern surgical devices and techniques have developed dramatically with the availability of new technologies. As a result, continual advancements have been achieved in intramedullary spinal cord tumor surgery, thus increasing the safety and effectiveness of tumor resection, and progressively improving the overall outcomes in patients undergoing such procedures.

Variations in referral patterns for hypophysectomies among pediatric patients with sellar and parasellar tumors

PURPOSE

It has been shown that patients admitted to high-volume hospitals for resection of sellar and parasellar lesions experience reduced mortality and morbidity. It remains unknown what preoperative factors influence admission to high-volume centers. We report a nationwide analysis of patients <18 years of age undergoing neurosurgical intervention for these lesions.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample was performed with additional factors from the Area Resource File. International Classification of Diseases, 9th Revision diagnosis/procedural codes were used to identify patients undergoing resection of tumors from the pituitary gland or related structures. Patients >or=18 years old were excluded. Covariates included age, gender, race, and insurance status. Multivariate analysis was performed using multiple logistic regression models. A p value <0.05 was considered statistically significant.

RESULTS

In total, 1,063 patients were identified. Most (69.8%) were seen at low-volume centers. Mean (median) patient age was 13.7 (15) years. The majority of patients were female (54.8%), white (61.9%), and insured (90.3%). Hispanics were 44% less likely (odds ratio (OR) 0.56, 95% confidence interval (CI) 0.34-0.92, p < 0.05) to be seen at high-volume centers than their Caucasian counterparts. Each increase in 2-year patient age category was associated with greater access to high-volume centers (OR 1.12, 95% CI 1.03-1.23, p < 0.05), relative to 0-2 years old. Female gender, insurance status, county poverty, neurosurgeon density, and calendar year were not significantly associated with admission to high-volume centers.

CONCLUSIONS

Age and racial disparities play a significant role in access neurosurgical care, affecting admission of pediatric patients to high-volume neurosurgical centers across the USA.

Defining future directions in spinal cord tumor research: proceedings from the National Institutes of Health workshop

The relative rarity of spinal cord tumors has hampered the study of these uncommon nervous system malignancies. Consequently, the understanding of the fundamental biology and optimal treatment of spinal cord tumors is limited, and these cancers continue to inflict considerable morbidity and mortality in children and adults. As a first step to improving the outcome of patients affected with spinal cord tumors, the National Institutes of Health Office of Rare Diseases Research in cooperation with the National Cancer Institute and the National Institute of Neurological Disorders and Stroke convened a workshop to discuss the current status of research and clinical management of these tumors. The overall goal of this meeting was to initiate a process that would eventually translate fundamental basic science research into improved clinical care for this group of patients. Investigational priorities for each of these areas were established, and the opportunities for future multidisciplinary research collaborations were identified.

Prognostic factors in pediatric high-grade astrocytoma: the importance of accurate pathologic diagnosis

To characterize a population of pediatric high-grade astrocytoma (HGA) patients by confirming the proportion with a correct diagnosis, and determine prognostic factors for survival in a subset diagnosed with uniform pathologic criteria. Sixty-three children diagnosed with HGA were treated at the Johns Hopkins Hospital between 1977 and 2004. A single neuropathologist (P.C.B.) reviewed all available histologic samples (n = 48). Log-rank analysis was used to compare survival by patient, tumor, and treatment factors. Median follow-up was 16 months for all patients and 155 months (minimum 54 months) for surviving patients. Median survival for all patients (n = 63) was 14 months with 10 long-term survivors (survival >48 months). At initial diagnosis, 27 patients were grade III (43%) and 36 grade IV (57%). Forty-eight patients had pathology slides available for review, including seven of ten long-term surviving patients. Four patients had non-HGA pathology, all of whom were long term survivors. The remaining 44 patients with confirmed HGG had a median survival of 14 months and prognostic analysis was confined to these patients. On multivariate analysis, five factors were associated with inferior survival: performance status (Lansky) <80% (13 vs. 15 months), bilaterality (13 vs. 19 months), parietal lobe location (13 vs. 16 months), resection less than gross total (13 vs. 22 months), and radiotherapy dose <50 Gy (9 vs. 16 months). Among patients with more than one of the five adverse factors (n = 27), median survival and proportion of long-term survivors were 12.9 months and 0%, compared with 41.4 months and 18% for patients with 0-1 adverse factors (n = 17). In an historical cohort of children with HGA, the potential for long term survival was confined to the subset with less than two of the following adverse prognostic factors: low performance status, bilaterality, parietal lobe site, less than gross total resection, and radiotherapy dose <50 Gy. Pathologic misdiagnosis should be suspected in patients who are long term survivors of a pediatric high grade astrocytoma.

Factors associated with progression-free survival and long-term neurological outcome after resection of intramedullary spinal cord tumors: analysis of 101 consecutive cases

OBJECT

With the introduction of electrophysiological spinal cord monitoring, surgeons have been able to perform radical resection of intramedullary spinal cord tumors (IMSCTs). However, factors associated with tumor resectability, tumor recurrence, and long-term neurological outcome are poorly understood.

METHODS

The authors retrospectively reviewed 101 consecutive cases of IMSCT resection in adults and children at a single institution. Neurological function and MR images were evaluated preoperatively, at discharge, 1 month after surgery, and every 6 months thereafter. Factors associated with gross-total resection (GTR), progression-free survival (PFS), and long-term neurological improvement were assessed using multivariate regression analysis.

RESULTS

The mean age of the patients was 41 +/- 18 years and 17 (17%) of the patients were pediatric. Pathological type included ependymoma in 51 cases, hemangioblastoma in 15, pilocytic astrocytoma in 16, WHO Grade II astrocytoma in 10, and malignant astrocytoma in 9. A GTR was achieved in 60 cases (59%). Independent of histological tumor type, an intraoperatively identifiable tumor plane (OR 25.3, p < 0.0001) and decreasing tumor size (OR 1.2, p = 0.05) were associated with GTR. Thirty-four patients (34%) experienced acute neurological decline after surgery (associated with increasing age [OR 1.04, p = 0.02] and with intraoperative change in motor evoked potentials [OR 7.4, p = 0.003]); in 14 (41%) of these patients the change returned to preoperative baseline within 1 month. In 31 patients (31%) tumor progression developed by last follow-up (mean 19 months). Tumor histology (p < 0.0001) and the presence of an intraoperatively identified tumor plane (hazard ratio [HR] 0.44, p = 0.027) correlated with improved PFS. A GTR resulted in improved PFS for hemangioblastoma (HR 0.004, p = 0.04) and ependymoma (HR 0.2, p = 0.02), but not astrocytoma. Fifty-five patients (55%) maintained overall neurological improvement by last follow-up. The presence of an identifiable tumor plane (HR 3.1, p = 0.0004) and improvement in neurological symptoms before discharge (HR 2.3, p = 0.004) were associated with overall neurological improvement by last follow-up (mean 19 months).

CONCLUSIONS

Gross-total resection can be safely achieved in the vast majority of IMSCTs when an intraoperative plane is identified, independent of pathological type. The incidence of acute perioperative neurological decline increases with patient age but will improve to baseline in nearly half of patients within 1 month. Long-term improvement in motor, sensory, and bladder dysfunction may be achieved in a slight majority of patients and occurs more frequently in patients in whom a surgical plane can be identified. A GTR should be attempted for ependymoma and hemangioblastoma, but it may not affect PFS for astrocytoma. For all tumors, the intraoperative finding of a clear tumor plane of resection carries positive prognostic significance across all pathological types.

Continuous monitoring of cerebrovascular pressure reactivity after traumatic brain injury in children

OBJECTIVE

We hypothesized that pressure reactivity index (PRx) values indicating preserved cerebrovascular pressure autoregulation would be associated with survival in children with traumatic brain injury (TBI). This hypothesis was tested in a prospective, blinded, observational, pilot study.

METHODS

Twenty-one children admitted between May 2006 and September 2008 with severe TBI necessitating invasive intracranial pressure monitoring were enrolled in this study. The PRx was continuously monitored as a moving, linear correlation coefficient between low-frequency waves of intracranial and arterial blood pressures. Positive values of PRx approaching 1 indicate impaired cerebrovascular pressure reactivity, whereas negative PRx values or values close to 0 indicate preserved cerebrovascular pressure reactivity. Survival was the primary outcome and was compared with the average PRx value obtained during the intracranial pressure-monitoring period.

RESULTS

PRx was associated with survival in this cohort; survivors (N = 15) had a mean PRx +/- SD of 0.08 +/- 0.19, and nonsurvivors (N = 6) had a mean PRx of 0.69 +/- 0.21 (P = .0009). In this sample, continuous PRx monitoring suggested impaired cerebrovascular pressure reactivity at low levels of cerebral perfusion pressure (CPP) and intact cerebrovascular pressure reactivity at higher levels of CPP.

CONCLUSIONS

Intact cerebrovascular pressure reactivity quantified with the PRx is associated with survival after severe head trauma in children. The PRx is CPP dependent in children. The PRx may be useful for defining age-specific and possibly patient-specific optimal targets for CPP after TBI.

Surgical considerations of spinal ependymomas in the pediatric population

OBJECTIVES

The objective of this manuscript is to discuss current management strategies regarding pediatric patients with intramedullary spinal cord ependymomas. Spinal ependymoma is the second most common spinal cord tumor in children. The clinical evaluation of these patients, operative techniques, postoperative management considerations, and long-term outcomes are discussed.

INTRODUCTION

The gold standard for the treatment of spinal ependymoma continues to be gross total resection. Patients with residual tumor postoperatively may benefit from adjuvant radiation therapy. Intraoperative monitoring is critical to minimize permanent postoperative neurologic deficit.

CONCLUSION

Patients requiring multilevel laminectomy may benefit from concomitant laminoplasty or instrumented fusion to avoid progressive spinal column deformity.

Incidence of symptomatic retethering after surgical management of pediatric tethered cord syndrome with or without duraplasty

BACKGROUND

Cord retethering and other postoperative complications can occur after the surgical untethering of a first-time symptomatic tethered cord. It is unclear if using duraplasty vs. primary dural closure in the initial operation is associated with decreased incidence of either immediate postoperative complications or subsequent symptomatic retethering. It is also unclear if different etiologies are associated with different outcomes after each method of closure. We reviewed our pediatric experience in first-time surgical untethering of symptomatic tethered cord syndrome (TCS) to identify the incidence of postoperative complications and symptomatic retethering after duraplasty vs. primary closure.

MATERIALS AND METHODS

We retrospectively reviewed 110 consecutive pediatric (<18 years old) cases of first-time symptomatic spinal cord untethering at our institution over a 10-year period. Incidence of postoperative complications and symptomatic retethering were compared in cases with duraplasty vs. primary dural closure use.

RESULTS

Mean age was 5.7 +/- 4.8 years old. "Complex" etiologies included lipomyelomeningocele or prior lipomyelomeningocele repair in 22 (20%) patients, prior myelomeningocele repair in 35 (32%), and concurrent lumbosacral lipoma in 18 (16%). "Noncomplex etiologies" included fatty filum in 26 (24%) and split cord malformation in five (4%). Seventy-five (68%) cases underwent primary dural closure vs. 35 (32%) with duraplasty. Twenty-nine (26%) patients experienced symptomatic retethering at a median [interquartile range (IQR)] of 30.5 [20.75-41.75] months postoperatively. There was no difference in incidence of postoperative cerebrospinal fluid leak, surgical site infection, or median [IQR] length of stay in patients receiving primary dural closure [4 (5%), 7 (9%), and 5 (4-6) days, respectively] vs. duraplasty [3 (9%), 3 (9%), and 6 [5-8] days, respectively], p > 0.05. Complex etiologies were more likely to retether than noncomplex etiologies after primary closure (33.6% vs. 6.6%, p = 0.05) but not after duraplasty (13.7% vs. 5.4%, p = 0.33). Duraplasty graft type (polytetrafluoroethylene vs. bovine pericardium) was not associated with pseudomeningocele or retethering.

CONCLUSION

In our experience, the increased rate of symptomatic retethering observed with complex pediatric TCS (pTCS) etiologies after primary dural closures was not observed when duraplasty was instituted. Expansile duraplasty may be valuable specifically in the management of patient subgroups with complex pTCS etiologies.

Pediatric tethered cord syndrome: response of scoliosis to untethering procedures. Clinical article

OBJECT

Tethered cord syndrome (TCS) is frequently associated with scoliosis in the pediatric population. Following spinal cord untethering, many patients continue to experience progression of spinal deformity. However, the incidence rate, time course, and risk factors for scoliosis progression following tethered cord release remain unclear. The aim of this study was to determine factors associated with scoliosis progression and whether tethered cord release alone would halt curve progression in pediatric TCS.

METHODS

The authors retrospectively reviewed 27 consecutive pediatric cases of spinal cord untethering associated with scoliosis. The incidence rate and factors associated with scoliosis progression (> 10 degrees increased Cobb angle) after untethering were evaluated using the Kaplan-Meier method.

RESULTS

The mean age of the patients was 8.9 years. All patients underwent cord untethering for lower-extremity weakness, back and leg pain, or bowel and bladder changes. Mean +/- SD of the Cobb angle at presentation was 41 +/- 16 degrees . The cause of the spinal cord tethering included previous myelomeningocele repair in 14 patients (52%), fatty filum in 5 (18.5%), lipomeningocele in 3 (11%), diastematomyelia in 2 (7.4%), arthrogryposis in 1 (3.7%), imperforate anus with an S-2 hemivertebra in 1 (3.7%), and lipomyelomeningocele with occult dysraphism in 1 (3.7%). Mean follow-up was 6 +/- 2 years. Twelve patients (44%) experienced scoliosis progression occurring a median of 2.4 years postoperatively and 8 (30%) required subsequent fusion for progression. At the time of untethering, scoliosis < 40 degrees was associated with a 32% incidence of progression, whereas scoliosis > 40 degrees was associated with a 75% incidence of progression (p < 0.01). Patients with Risser Grades 0-2 were also more likely to experience scoliosis progression compared with Risser Grades 3-5 (p < 0.05). Whereas nearly all patients with Risser Grades 0-2 with curves > 40 degrees showed scoliosis progression (83%), 54% of patients with Risser Grades 0-2 with curves < 40 degrees progressed, and no patients with Risser Grades 3-5 with curves < 40 degrees progressed following spinal cord untethering.

CONCLUSIONS

In this experience with pediatric TCS-associated scoliosis, patients with Risser Grades 3-5 and Cobb angles < 40 degrees did not experience curve progression after tethered cord release. Patients with Risser Grades 0-2 and Cobb angles > 40 degrees were at greatest risk of curve progression after cord untethering. Pediatric patients with TCS-associated scoliosis should be monitored closely for curve progression using standing radiographs after spinal cord untethering, particularly those with curves > 40 degrees or who have Risser Grades 0-2.

Neurological outcome after surgical management of adult tethered cord syndrome

Object

Although postsurgical neurological outcomes in patients with tethered cord syndrome (TCS) are well known, the rate and development of neurological improvement after first-time tethered cord release is incompletely understood. The authors reviewed their institutional experience with the surgical management of adult TCS to assess the time course of symptomatic improvement, and to identify the patient subgroups most likely to experience improvement of motor symptoms.

Methods

The authors retrospectively reviewed 29 consecutive cases of first-time adult tethered cord release. Clinical symptoms of pain and motor and urinary dysfunction were evaluated at 1 and 3 months after surgery, and then every 6 months thereafter. Rates of improvement in pain and motor or urinary dysfunction over time were identified, and presenting factors associated with improvement of motor symptoms were assessed using a multivariate survival analysis (Cox model).

Results

The mean patient age was 38 ± 13 years. The causes of TCS included lipomyelomeningocele in 3 patients (10%), tight filum in 3 (10%), lumbosacral lipoma in 4 (14%), intradural tumor in 3 (10%), previous lumbosacral surgery in 2 (7%), and previous repair of myelomeningocele in 14 (48%). The mean ± SD duration of symptoms before presentation was 5 ± 7 months. Clinical presentation included diffuse pain/parasthesias in both lower extremities in 13 patients (45%), or perineal distribution in 18 (62%), lower extremity weakness in 17 (59%), gait difficulties in 17 (59%), and bladder dysfunction in 14 (48%). Laminectomy was performed in a mean of 2.5 ± 0.7 levels per patient, and 9 patients (30%) received duraplasty. At 18 months postoperatively, 47% of patients had improved urinary symptoms, 69% had improved lower extremity weakness and gait, and 79% had decreased painful dysesthesias. Median time to symptomatic improvement was least for pain (1 month), then motor (2.3 months), and then urinary symptoms (4.3 months; p = 0.04). In patients demonstrating improvement, 96% improved within 6 months of surgery. Only 4% improved beyond 1-year postoperatively. In a multivariate analysis, the authors found that patients who presented with asymmetrical lower extremity weakness (p = 0.0021, hazard ratio 5.7) or lower extremity hyperreflexia (p = 0.037, hazard ratio = 4.1) were most likely to experience improvement in motor symptoms.

Conclusions

In the authors' experience, pain and motor and urinary dysfunction improve postoperatively in the majority of patients. The rate of symptomatic improvement was greatest for pain resolution, followed by motor, and then urinary improvement. Patients who experienced improvement in any symptom had done so by 6 months after tethered cord release. Patients with asymmetrical motor symptoms or lower extremity hyperreflexia at presentation were most likely to experience improvements in motor symptoms. These findings may help guide patient education and surgical decision-making.

Intraventricular ganglioglioma: a short illustrated review

The following review of the literature describes the ganglioglioma, an uncommon mixed glioneuronal neoplasm, most often of low-grade histology, with a small, albeit well-documented, malignant potential. These tumors exhibit a strong epileptogenic propensity and most often present as new onset seizures or are discovered after a long history of refractory epilepsy. Despite their indolent course, the importance of gross total resection is well recognized to prevent anaplastic and malignant degeneration. Morphologically, the neoplasm is often cystic with an enhancing mural nodule, but can also be entirely solid. They are most often found in the temporal lobe but have been found throughout the neuraxis. An exceedingly rare location of the ganglioglioma is within the lateral ventricle. A systematic literature search revealed only eight reports documenting the occurrence of a ganglioglioma within the lateral ventricle. We describe an illustrative case of an intraventricular ganglioglioma with a prominent cystic component and enhancing mural nodule, which represents the classic radiographic appearance of gangliogliomas described in other locations. A superior parietal lobule approach offered excellent surgical access for tumor removal and the patient has remained free of neurological deficits following surgery. Regardless of location within the central nervous system, ganglioglioma should be on the differential diagnosis for any cystic mass with a mural nodule, particularly in the setting of epilepsy.

Keyhole to the brain: Walter Dandy and neuroendoscopy

In the early 1920s, Walter E. Dandy began translating the field of endoscopy to neurosurgery. In the ensuing years, Dandy, who would become known as the "Father of Neuroendoscopy," applied his own ingenuity in combination with guidance from prominent medical contemporaries in the development of the early neuroendoscope. This paper reviews his contributions to the early evolution of this growing and important field of neurosurgery.

Treatment of diffuse intrinsic brainstem gliomas: failed approaches and future strategies

Diffuse intrinsic pontine gliomas constitute ~ 60-75% of tumors found within the pediatric brainstem. These malignant lesions present with rapidly progressive symptoms such as cranial nerve, long tract, or cerebellar dysfunctions. Magnetic resonance imaging is usually sufficient to establish the diagnosis and obviates the need for surgical biopsy in most cases. The prognosis of the disease is dismal, and the median survival is < 12 months. Resection is not a viable option. Standard therapy involves radiotherapy, which produces transient neurological improvement with a progression-free survival benefit, but provides no improvement in overall survival. Clinical trials have been conducted to assess the efficacy of chemotherapeutic and biological agents in the treatment of diffuse pontine gliomas. In this review, the authors discuss recent studies in which systemic therapy was administered prior to, concomitantly with, or after radiotherapy. For future perspective, the discussion includes a rationale for stereotactic biopsies as well as possible therapeutic options of local chemotherapy in these lesions.

Neurological grading, survival, MR imaging, and histological evaluation in the rat brainstem glioma model

OBJECTIVE

Convection-enhanced delivery using carboplatin in brainstem glioma models was reported to prolong survival. Functional impairment is of additional importance to evaluate the value of local chemotherapy. We established a neurological scoring system for the rat brainstem glioma model.

MATERIAL AND METHODS

In 46 male Fisher rats stereotactically 10(5) F-98 cells were implanted at 1.4-mm lateral to midline and at the lambdoid suture using guided screws. Following 4 days local delivery was performed using Alzet pumps (1 microl/h over 7 days) with either vehicle (5% dextrose) or carboplatin via one or two cannulas, respectively. All rats were subsequently tested neurologically using a specified neurological score. In 38 animals survival time was recorded. Representative MR imaging were acquired in eight rats, respectively, at day 12 after implantation. HE staining was used to evaluate tumor extension.

RESULTS

Neurological scoring showed significantly higher impairment in the high dose carboplatin group during the treatment period. Survival was significantly prolonged compared to control animals in the high dose carboplatin-one cannula group as well as in both low dose carboplatin groups (18.6 +/- 3 versus 26.3 +/- 9, 22.8 +/- 2, 23.6 +/- 2 days; p < 0.05). Overall neurological grading correlated with survival time. MR imaging showed a focal contrast enhancing mass in the pontine brainstem, which was less exaggerated after local chemotherapy. Histological slices visualized decreased cellular density in treatment animals versus controls.

CONCLUSION

Local chemotherapy in the brainstem glioma model showed significant efficacy for histological changes and survival. Our neurological grading enables quantification of drug and tumor-related morbidity as an important factor for functional performance during therapy.

A review on the management of epilepsy associated with hypothalamic hamartomas

INTRODUCTION

Hypothalamic hamartomas are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Patients may be asymptomatic, but the usual presentation is gelastic seizures, precocious puberty, and/or developmental delay.

CLINICAL PRESENTATION

Without surgical intervention, the gelastic seizures, which are typically present in childhood, may progress to other seizure types, including generalized epilepsy, and are generally refractory to antiepileptic drugs.

SUMMARY

This review will discuss the clinical and electrophysiologic aspects of these lesions, as well as treatment options, including surgery, endoscopy, and radiosurgery.

Neurosurgical applications of laser technology

Although lasers have been used in clinical neurosurgery for over 40 years, technological advancements have expanded their use and improved technical application. Originally applied to brain tumors to confer destructive oncolysis, lasers have been used over the last few decades to incise, fenestrate, and repair tissues and now are being used for cerebrovascular bypass techniques. In this chapter, a brief history on the evolution of lasers in neurosurgery will be discussed, and technical and clinical aspects of current applications will presented. Such applications include: laser scalpel for spinal cord tumors and lipomas, fenestration of arachnoid cysts, cerebrovascular bypass with the ELANA device, laser-induced interstitial thermotherapy for brain tumors, laser tissue soldering for dural repair, and percutaneous laser disc decompression.

Intra-operatively obtained human tissue: protocols and techniques for the study of neural stem cells

The discoveries of neural (NSCs) and brain tumor stem cells (BTSCs) in the adult human brain and in brain tumors, respectively, have led to a new era in neuroscience research. These cells represent novel approaches to studying normal phenomena such as memory and learning, as well as pathological conditions such as Parkinson's disease, stroke, and brain tumors. This new paradigm stresses the importance of understanding how these cells behave in vitro and in vivo. It also stresses the need to use human-derived tissue to study human disease because animal models may not necessarily accurately replicate the processes that occur in humans. An important, but often underused, source of human tissue and, consequently, both NSCs and BTSCs, is the operating room. This study describes in detail both current and newly developed laboratory techniques, which in our experience are used to process and study human NSCs and BTSCs from tissue obtained directly from the operating room.

Angiocentric glioma: a case series

OBJECT

Angiocentric glioma was recently recognized as a distinct clinicopathological entity in the 2007 World Health Organization Classification of Tumours of the Central Nervous System. The authors present the first 3 pediatric cases of angiocentric glioma encountered at their institution and review the literature of reported cases to elucidate the characteristics and outcomes of pediatric patients with this novel tumor.

METHODS

The children in the 3 cases of angiocentric glioma were 10, 10, and 13 years old. Two presented with intractable seizures and 1 with worsening headache and several months of decreasing visual acuity. Twenty-five cases, including the 3 first described in the present paper, were culled from the literature.

RESULTS

In all 3 cases, MR imaging demonstrated a superficial, nonenhancing, T2-hyperintense lesion in the left temporal lobe. Histologically, the tumors were composed of monomorphous cells with a strikingly perivascular orientation that were variably reactive for glial fibrillary acidic protein and epithelial membrane antigen. Surgical treatment resulted in gross-total resection in all 3 cases. By 24, 9, and 6 months after surgery, all 3 patients remained seizure free without focal neurological deficits.

CONCLUSIONS

Among 25 cases of angiocentric glioma, seizure was the most common symptom at presentation. Magnetic resonance imaging demonstrated supratentorial, nonenhancing, T1-hypointense, T2-hyperintense lesions. Gross-total resection of this lesion yields excellent results.

Current Technological Advances of Bipolar Coagulation

Background:

Heat has been used to control bleeding for thousands of years. In the 1920s, this concept was applied to the development of electrosurgical instruments and was used to control hemorrhage during surgical procedures. In the time that has passed since its first use, electrosurgery has evolved into modernday bipolar technology, involving a diverse group of coagulation instruments.

Methods:

We review the evolution and advances in electrosurgery, specifically bipolar coagulation, and the current technologies available for intraoperative hemorrhage control.

Results:

Electrosurgery has evolved to include highly accurate devices that deliver thermal energy via nonstick and noncontact methods. Over time, the operative range of coagulation instruments has increased dramatically with the incorporation of irrigating pathways, a wide range of instrument tips to perform various functions, and the application of bipolar technology to microforceps and microscissors for minimally invasive procedures.

Conclusion:

Electrosurgical devices and techniques, especially bipolar coagulation, have developed significantly with the availability of new technologies. This has led to better intraoperative coagulation control while minimizing iatrogenic damage associated with heat spread and tissue adherence, thus potentially improving outcomes for neurosurgical procedures.