Laser speckle imaging to improve clinical outcomes for patients with trigeminal neuralgia undergoing radiofrequency thermocoagulation.

OBJECTIVE: Percutaneous treatments for trigeminal neuralgia are safe, simple, and effective for achieving good pain control. Procedural risks could be minimized by using noninvasive imaging techniques to improve the placement of the radiofrequency thermocoagulation probe into the trigeminal ganglion. Positioning of a probe is crucial to maximize pain relief and to minimize unwanted side effects, such as denervation in unaffected areas. This investigation examined the use of laser speckle imaging during probe placement in an animal model. METHODS: This preclinical safety study used nonhuman primates, Macaca nemestrina (pigtail monkeys), to examine whether real-time imaging of blood flow in the face during the positioning of a coagulation probe could monitor the location and guide the positioning of the probe within the trigeminal ganglion. RESULTS: Data from 6 experiments in 3 pigtail monkeys support the hypothesis that laser imaging is safe and improves the accuracy of probe placement. CONCLUSIONS: Noninvasive laser speckle imaging can be performed safely in nonhuman primates. Because improved probe placement may reduce morbidity associated with percutaneous rhizotomies, efficacy trials of laser speckle imaging should be conducted in humans.

Diffusion tensor imaging in pediatric Chiari type I malformation.

AIM: Chiari type I malformation (C1M) may be symptomatic or asymptomatic as an incidental finding. In this retrospective study, we applied diffusion tensor imaging (DTI) to study the brainstem and cerebellar white matter tracts in C1M. METHOD: Diffusion tensor imaging (DTI) data were acquired on a 1.5T MR-scanner using balanced pairs of diffusion gradients along 20 non-collinear directions. Measurements from regions of interest in each pontine corticospinal tract, medial leminscus, and middle cerebellar peduncle (MCP) and in the lower brainstem were obtained for fractional anisotropy and mean, axial, and radial diffusivity. Values in symptomatic and asymptomatic children, and children with and without hydromyelia were compared using analysis of variance. RESULTS: Fifteen children with C1M (10 males, five females; six symptomatic [four with hydromyelia] and nine asymptomatic) were included. Median age was 6 years 5 months (range 2y 10mo-15y 4mo). No significant differences in DTI scalars were found in the lower brainstem. In both MCPs, axial diffusivity values were lower in symptomatic than in asymptomatic children (p=0.049 and p=0.035 respectively) and higher in children with hydromyelia versus without hydromyelia (p=0.018 and p=0.006 respectively). In the left MCP, mean diffusivity values were lower in symptomatic than in asymptomatic children (p=0.047). INTERPRETATION: Our results show that microstructural tissue alterations may be present in C1M. Additionally, our study suggests a specific role for the MCPs in C1M. Further large-scale studies are warranted.

Computer-aided design and manufacturing in craniosynostosis surgery.

BACKGROUND: Considerable operative time is expended during the planning, shaping, and reconfiguring of the cranial vault in the pursuit of symmetry during open craniosynostosis surgery. Computer-aided design and manufacturing has recently been implemented in orthognathic surgery and complex craniomaxillofacial reconstruction as a means of optimizing operative accuracy and efficiency. In this report, we highlight our growing experience with this promising modality for the preoperative planning and intraoperative execution of cranial vault remodeling in patients with both simple and complex forms of craniosynostosis. METHODS: Computer-assisted surgical planning begins with acquisition of high-resolution computed tomography scans of the craniofacial skeleton. An Internet-based teleconference is then held between the craniofacial and biomedical engineering teams and provides a forum for virtual manipulation of the patient's preoperative three-dimensional computed tomography with real-time changes and feedback. Through virtual surgical planning, osteotomies are designed and calvarial bones reconfigured to achieve the desired cranial vault appearance. Cutting and positioning guides are manufactured to transform the virtual plan into a reality. RESULTS: From February to March 2012, 4 children (aged 9 months to 6 years) with craniosynostosis underwent computer-assisted simulation and surgery. Diagnoses included metopic, unicoronal (n = 2), and multisutural synostoses (sagittal and left unicoronal). Open craniofacial repairs were performed as virtually planned, including front o-orbital remodeling, fronto-orbital advancement, and anterior two-thirds calvarial remodeling, respectively. Cutting and final positioning guides demonstrated excellent fidelity and ease of use. CONCLUSIONS: Computer-aided design and manufacturing may offer a platform for optimizing operative efficiency, precision, and accuracy in craniosynostosis surgery, while accelerating the learning curve for future trainees.

Glycerol rhizotomy and radiofrequency thermocoagulation for trigeminal neuralgia in multiple sclerosis.

OBJECT: Patients with trigeminal neuralgia due to multiple sclerosis (TN-MS) and idiopathic TN (ITN) who underwent glycerol rhizotomy (GR) and radiofrequency thermocoagulation with glycerol rhizotomy (RFTC-GR) were compared to investigate the effectiveness of these percutaneous ablative procedures in the TN-MS population. METHODS: Between 1998 and 2010, 822 patients with typical TN were evaluated; 63 (8%) had TN-MS and 759 (92%) had ITN. Pain relief comparisons were made between 22 GR procedures in patients with TN-MS and 470 GR procedures in patients with ITN; 50 RFTC-GR procedures in patients with TN-MS and 287 RFTC-GR procedures in patients with ITN were compared. Analysis of time to recurrence included only procedures that achieved complete pain relief without medications. RESULTS: After 15 of the GR procedures (68%) in patients with TN-MS and 315 of the procedures (67%) in those with ITN, the patients were pain free without medications (p = 0.736). After 36 of the RFTC-GR procedures (72%) in patients with TN-MS and 210 of the procedures (73%) in those with ITN, the patients were pain free without medications (p = 0.657). The difference in pain relief between GR and RFTC-GR for patients with TN-MS was not significant (p = 0.447). The median time to failure of GR was 20 months in patients with TN-MS compared with 25 months in those with ITN (p = 0.403). The median time to failure of RFTC-GR was 26 months in the TN-MS population compared with 21 months in the ITN population (p = 0.449). Patients with TN-MS experienced similar times to recurrence whether they were treated with GR or RFTC-GR (p = 0.431). CONCLUSIONS: Pain relief and durability of relief outcomes of GR and RFTC-GR were similar in patients with TN-MS and ITN, reinforcing their use as preferred treatments of TN-MS. The GR and RFTC-GR achieved comparable outcomes in patients with TN-MS, suggesting that both can be used to good effect.

Treatment of choroid plexus tumors: a 20-year single institutional experience.

OBJECT: Choroid plexus tumors (CPTs) are rare intracranial neoplasms that constitute approximately 2%-5% of all pediatric brain tumors. Most of these tumors present with severe hydrocephalus. The optimal perioperative management and oncological care remain a matter of debate. The authors present the epidemiological and clinical features of CPTs from a 20-year single-institutional experience. METHODS: A total of 39 consecutive patients with pathologically proven CPTs (31 choroid plexus papillomas [CPPs] and 8 choroid plexus carcinomas [CPCs]) were included in this series. Patient demographics, clinical presentation, comorbidities, indications for surgery, radiological studies, tumor location, and all operative variables were reviewed for each case. Multivariate regression analysis was performed to identify independent predictors of tumor recurrence and survival. RESULTS: The overall mean age (± SD) was 13.13 ± 19.59 years (15.27 ± 21.10 years in the CPP group and 3.66 ± 3.59 years in the CPC group). Hydrocephalus was noted at presentation in 34% of patients. The most common presenting symptoms were headache (32%) and nausea/vomiting (26%). Gross-total resection (GTR) was achieved in 86% of CPPs and in 71% of CPCs (p = 0.57). There was 100% survival in patients with CPPs observed at the 5- and 10-year follow-up and 71% survival in patients with CPCs at the 5-year follow-up. In a multivariate regression analysis, a diagnosis of papilloma, preoperative vision changes, or hydrocephalus; right ventricle tumor location; and GTR were all independently associated with a decreased likelihood of tumor recurrence at last follow-up. CONCLUSIONS: The authors' study suggests that patients with CPCs are more likely to experience local recurrence and metastasis; hence, GTR with chemotherapy and radiotherapy, particularly for CPCs, is pivotal in preventing recurrence and prolonging survival. While GTR was important for local control following resection of CPPs, it had a minimal effect on prolonging survival in this patient cohort.

Harvey Cushing's contributions to motor mapping: 1902-1912.

This review examined Dr. Harvey Cushing's cases in the surgical records of Johns Hopkins Hospital, from 1896 to 1912. 41 patients who underwent cortical stimulation for intra-operative motor mapping were selected for further analysis. We demonstrate that Cushing used cortical stimulation to define primary motor and sensory cortices in the treatment of tumors, trauma, and epilepsy, within adult and pediatric populations. In addition, he performed stimulation of sub-cortical white matter during 4 of these surgeries, setting the stage for contemporary use of this technique in improving post-operative outcomes. This review of Cushing's early intra-operative motor mapping illuminates his contributions, and clarifies his influence on the evolution of cortical mapping from an experimental technique to a staple of contemporary neurosurgery.

Effectiveness of repeat glycerol rhizotomy in treating recurrent trigeminal neuralgia.

BACKGROUND: Percutaneous glycerol rhizotomy (GR) is used to treat trigeminal neuralgia (TN), with satisfactory pain relief lasting 2 to 3 years in most patients after the first intervention. The efficacy of subsequent GRs, however, has not been studied. OBJECTIVE: To compare the pain relief and durability achieved by the first GR with those obtained after subsequent GRs in a retrospective cohort of TN patients. METHODS: Between 1998 and 2010, 548 patients with TN underwent 708 GRs. After exclusions, 430 initial GRs (GR1) and 114 subsequent GRs (GR2+) were compared in terms of initial pain relief, durability, sensory change, and complications. Durability was assessed by determining median time to treatment failure for all GRs achieving complete pain relief without medications (n = 375: 264 failures, 111 censored). Predictors of initial pain relief were assessed by logistic regression, and predictors of failure were assessed by Cox regression analysis. RESULTS: After GR1, pain relief results were as follows: 285 patients (66%) were pain free without medications, 26 (6%) were pain free with medications, 66 (15%) improved, and 53 (12%) were unchanged. After GR2+, results were as follows: 90 patients (79%) were pain free without medications, 6 (5%) were pain free with medications, 7 (6%) improved, and 11 (10%) were unchanged (P = .03). Median time to treatment failure was 26 months after GR1 and 25 months after GR2+ (P = .34). On multivariate analysis, prior GR was a positive predictor of initial pain relief (odds ratio, 2.067; 95% confidence interval, 1.243-3.437; P = .005) and had no effect on durability. CONCLUSION: TN patients experienced greater pain relief and equivalent durability after GR2+ beyond the initial treatment.

Surgical treatment of pediatric trigeminal neuralgia: case series and review of the literature.

PURPOSE: Pediatric trigeminal neuralgia (TN) is a rare entity. The purpose of this study was to retrospectively analyze a small series of pediatric patients diagnosed with TN and surgically treated with microvascular decompression (MVD) at a single center. METHODS: Nine patients were identified who presented with TN symptoms that began before the age of 18. Four were excluded because of delayed surgical intervention or successful medical management. We retrospectively reviewed the charts of 5 patients with classical TN who underwent MVD at or before the age of 18. RESULTS: Patient ages ranged from 3 to 18 years (average, 11.7) at the time of procedure. All five patients were female. Four patients underwent a single procedure and one had bilateral MVDs. In all six cases, vascular compression of the trigeminal nerve was found during surgery. Compression was venous in three cases, arterial in two, and both in one. Pain relief was complete following the procedure in five of six cases. Pain relief was incomplete but substantial in one patient, allowing her to discontinue anticonvulsant medications. Follow-up duration ranges from 9.1 to 24.8 months with an average of 15.3 (± 6.1) and a median of 12.7 months follow-up. There were no complications such as CSF leak, infection, or cranial nerve deficits. CONCLUSIONS: Until now, there had been no reports on the effectiveness of MVD performed before the age of 18 to treat TN. These preliminary results suggest MVD may be performed with good pain relief and minimal side effects in the pediatric population.

Harvey Cushing's case series of trigeminal neuralgia at the Johns Hopkins Hospital: a surgeon's quest to advance the treatment of the 'suicide disease'.

BACKGROUND: A review of Dr. Harvey Cushing's surgical cases at the Johns Hopkins Hospital provided insight into his early work on trigeminal neuralgia (TN). There was perhaps no other affliction that captured his attention in the way that TN did, and he built a remarkable legacy of successful treatment. At the time, surgical interventions carried an operative mortality of 20%. METHODS: The Johns Hopkins Hospital surgical records from 1896-1912 were reviewed to contribute new cases to the 20 reports provided by Dr. Cushing in his early publications in 1900 and 1905. This review uncovered 123 TN cases, representing 168 interventions. RESULTS: At the start of his career, Cushing treated TN mainly through Gasserion ganglion extirpations and peripheral neurectomies; however, he nearly abandoned these methods in favor of sensory root avulsion after 1906 and did not perform alcohol injections until his later years at Hopkins. Overall, Cushing had a 0.6% mortality rate; additionally, 91% of patients were improved at the time of discharge. However, 26% of patients had a recurrence requiring further intervention by Cushing. CONCLUSION: Modern day interventions of TN are reflective of the legacy left to us by Harvey Cushing, a pioneering forefather in neurosurgery. He pioneered the infra-arterial approach to excision of the Gasserion ganglion in face of problematic bleeding and later the use of sensory root avulsion to spare motor function. Through the evolution of his legacy and the refinement of original approaches, the quest to advance the treatment of TN took him along the trigeminal nerve from the periphery into the brain.

Surgical decompression for lumbar stenosis in pediatric achondroplasia.

BACKGROUND: Spinal stenosis is a common complication of achondroplasia. To our knowledge, no study has evaluated a greater than 2-year outcome after surgical intervention for spinal stenosis in such children or compared decompression with and without instrumentation in relation to revision surgery. Our purpose was to assess the efficacy of lumbar decompression and instrumentation for symptomatic stenosis in children with achondroplasia. METHODS: We retrospectively reviewed our institution's database to identify children (< or =18 y old) with achondroplasia undergoing initial spinal decompression for lumbar stenosis from 1995 through 2003. We identified 18 such patients and reviewed their medical records for demographic data, presenting signs and symptoms, and treatment and outcome data. Mean follow-up was 72.0+/-27.6 months. We determined each patient's symptom score (SS) based on presence of leg weakness, numbness, or pain; abnormal reflexes; incontinence; and walking intolerance (unable to walk > or =5 blocks). Each finding was scored 1 point (6 points maximum). Nine patients requiring revision surgery were assigned a revision postoperative SS. All patients were contacted at the end of data collection and assigned a final follow-up SS. Baseline SS values were compared with postoperative, revision postoperative, and final follow-up scores using a paired t test (alpha=0.05). RESULTS: The mean preoperative and final SS values were significantly different: 4.0+/-0.9 (most common symptoms, leg weakness and incontinence) and 1.6+/-1.7 (most common symptom, leg weakness), respectively. Nine patients underwent decompression with instrumentation initially; 9 did not; 7 of the latter required instrumentation during revision; and 2 of the former also required revision. Those without initial instrumentation were 3.5 times more likely (odds ratio=12.3) to require revision. CONCLUSIONS: Surgical decompression with instrumentation significantly reduced the symptoms of lumbar stenosis and the likelihood of revision surgery in children with achondroplasia. LEVEL OF EVIDENCE: Level III therapeutic study.

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.

Disparities in access to pediatric neurooncological surgery in the United States.

OBJECTIVE: The objective of this study was to investigate whether disparities in access to high-volume centers for neurooncological care existed in the United States in 1988-2005. METHODS: A retrospective analysis of the Nationwide Inpatient Sample (1988-2005) was performed, with additional factors incorporated from the Area Resource File (2006). International Classification of Diseases, Ninth Revision, diagnosis/procedure coding was used to identify patients. High-volume centers were defined as those with > or =50 neurosurgical cases per year. Patients >18 years of age were excluded. Covariates included age, gender, race, Charlson Index score, insurance, and county-level characteristics (including median home value, proportion of foreign born residents, and county neurosurgeon density). Multivariate analysis was performed by using multiple logistic regression models. P values of <.05 were considered statistically significant. RESULTS: A total of 4421 patients were identified; 1651 (37.34%) were admitted to high-volume centers. Overall access to high-volume centers improved slightly over the 18-year period (odds ratio [OR]: 1.04). Factors associated with greater access to high-volume centers included greater county neurosurgeon density (OR: 1.72) and greater county home value (OR: 1.66). Factors associated with worse access included Hispanic ethnicity (OR: 0.68) and each 1% increase in foreign residents per county (OR: 0.59). All reported P values were <.05. CONCLUSION: This study demonstrates that racial and socioeconomic disparities in access to high-volume neurooncological care exist for the pediatric population. We also identify numerous prehospital factors that potentially contribute to persistent disparities and may be amenable to change through national health policy interventions.

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.

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.

Magnetic resonance imaging characteristics of pilomyxoid astrocytoma.

OBJECTIVE: Pilomyxoid astrocytoma (PMA) is a recently identified pediatric low-grade neoplasm that was previously classified as pilocytic astrocytoma (PA), yet demonstrates unique histological features and more aggressive behavior. These tumors have been shown to have significantly shorter progression-free and overall survival probability than classical low-grade astrocytomas, as well as a high rate of cerebrospinal fluid (CSF) dissemination. This paper describes the radiographic features of PMA. METHODS: Magnetic resonance imaging (MRI) was obtained for ten PMAs. Radiographic characteristics of the tumor were recorded in each case. All tissue samples were independently reviewed for confirmation of pathologic diagnosis. RESULTS: All tumors appeared well-circumscribed with no evidence of peritumoral edema or parenchymal infiltration on MRI. All tumors except one originated from the midline of the neuroaxis. Specifically, five tumors (50.0%) were located in the hypothalamic region, two (20.0%) were located in the spine, two (20.0%) were located in the dorsal brainstem and one was located in the right thalamus. Five tumors (50.0%) demonstrated solid composition, with the remaining five showing some cystic components. Mass effect, hydrocephalus and central necrosis were observed in 62.5, 50.0 and 0.0% of cases, respectively. Eight tumors (80%) were hyperintense on T1-weighted MRI. Seven tumors (77.8%) were hyperintense on T2-weighted MRI. All tumors were hyperintense on fluid attenuated inversion recovery (FLAIR) sequence and hypointense on diffusion weighted imaging (DWI). Upon contrast administration, six tumors (60.0%) enhanced heterogeneously and four tumors (40.0%) enhanced homogenously. CONCLUSION: Pilomyxoid astrocytoma is a well-circumscribed pediatric neoplasm that commonly originates from the midline of the neuroaxis and lacks peritumoral edema or central necrosis. It is critical to recognize the predominantly solid and well-circumscribed nature of the neoplasm to avoid confusion with an infiltrating astrocytoma.

Outcome analysis of childhood low-grade astrocytomas.

BACKGROUND: We aimed to determine the long-term natural history of low-grade astrocytomas (LGA) in children, with respect to pathology, and to evaluate influence of treatment on survival. PATIENTS AND METHODS: A consecutive cohort of patients < or =21 years with surgically confirmed LGA from 1965 to 1996 was assembled. All available pathology specimens were reviewed, masked to original diagnosis, patient data, and neuroimaging. RESULTS: Two hundred seventy-eight children (160 males; mean age 9.1 years; tumor location: 77 cerebrum, 62 cerebellum, 51 hypothalamic, 30 thalamus, 9 ventricle, 40 brainstem, and 9 spine) were assessed. Among 246 specimens reviewed, diagnoses were 135 pilocytic astrocytoma (PA), 27 diffuse astrocytoma (DA), 75 unclassifiable well-differentiated astrocytoma (NOS), and 9 subependymal giant cell astrocytoma. At 5 and 10 years from initial surgery, for all LGA overall survival (OS) was 87% and 83%, while progression-free survival (PFS) was 55% and 42%, respectively. Original pathology diagnoses did not predict PFS (P = 0.47), but reviewed diagnoses were significantly associated with PFS (P = 0.007). Reviewed diagnoses were highly associated with OS (P < 0.0001), with 5-year OS for PA 96%, DA 48%, and NOS 86%; these differences remained significant when stratified by location or extent of resection. Among patients with residual tumor after surgery, 5-year PFS was 48% with observation alone (n = 114), no different (P = 0.32) from that achieved with immediate irradiation (n = 86). CONCLUSION: LGA, particularly PA, have excellent long-term OS. While tumor location and resection extent affect outcome, pathologic diagnosis when carefully interpreted significantly influences long-term survival. Immediate postoperative irradiation does not confer an advantage in delaying first progression in children with residual PA.

Catheters for chronic administration of drugs into brain tissue.

Methods to infuse drugs into the parenchyma of the central nervous system (CNS) have been reported as inconsistent or unpredictable. The source of variability appears to be a compromised seal between the tissue and the outer surface of the cannula. Failure of the tissue to seal to the cannula creates a path of least resistance. Rather than penetrate the target area, the drug backflows along the path of the cannula. This artifact can be difficult to detect because drugs enter the systemic circulation and provide some fraction of the intended therapy. Decreasing the rate of the infusion can reduce backflow. However, this may not be an attractive option for certain therapeutic targets because decreased infusion rates decrease the volume of drug distribution in normal tissue. Cannula design plays a role. Rigid catheters that are fixed to the skull will oppose movements of the brain and break the seal between the catheter and the tissue during chronic infusions. Flexible infusion cannulas, which can be readily made by modifying commercially available brain infusion catheters with plastic tubing, appear to provide consistent infusion results because they can move with the brain and maintain their tissue seal.

Antibiotic-impregnated shunt catheters for the treatment of infantile hydrocephalus.

INTRODUCTION: Antibiotic-impregnated shunt (AIS) components decrease shunt infections by preventing bacterial colonization that occurs during implantation. Despite studies showing improved efficacy in preventing infection however, concern still exists regarding using AIS components in infants, especially premature ones. In this study, clinical outcomes were assessed in infants with hydrocephalus (<1 year) following AIS placement. METHODS: A prospective observational study was conducted involving pediatric patients <1 year of gestational age with hydrocephalus who underwent placement of AIS components (ventriculoperitoneal, ventriculoatrial, and cystoperitoneal) as initial treatments, shunt revision surgery, or following previous placement of a ventricular access device (VAD, Rickman reservoir). Measured outcomes included: infection, shunt revision surgery, and complications. RESULTS: Seventy-four infants underwent 108 AIS procedures, and all were followed for over 9 months. Twenty-seven patients (36.5%) possessed previous VADs. Average weight and gestational age at birth were 1,976 g (range: 560-3,500 g) and 32.8 weeks (range: 23-41 weeks), respectively. The average age at the time of surgery was 14.6 weeks (range: 1 day to 50 weeks). Five infections occurred in 5 patients (4.6% of procedures, 6.75% of patients), 60% of which were very premature (<32 weeks). Thirty-three patients (44.6%) required shunt revision surgery, 5 (15%) for infection and 28 (85%) for malfunction. Three cerebrospinal fluid leaks occurred perioperatively without significant sequelae, and no mortalities occurred from the procedures. CONCLUSION: AIS systems can safely be used to treat hydrocephalus in pediatric patients <1 year old, even for those with a history of prematurity. One possible therapeutic application for such premature patients may be the incorporation of antibiotic impregnation into VADs or ventriculosubgaleal components to treat infants with hydrocephalus prior to definitive CSF shunt placement.