Faculty Bibliography

Purpose: Intracranial monitoring (IM) is a key diagnostic procedure for select patients with treatment-resistant epilepsy (TRE). Seizure focus resection may improve seizure control in both lesional and nonlesional TRE. IM itself is not considered to have therapeutic potential. We describe a cohort of patients with improved seizure control following IM without resective surgery. Methods: Over 12.5 years, 161 children underwent 496 surgeries including intracranial monitoring. We retrospectively reviewed the patients' charts, operative reports, and radiologic scans, under an institutional review board-approved protocol. Key Findings: Seventeen patients underwent only IM, without additional resective surgery, and seven had a dramatic improvement in their epilepsy; six of the seven patients are seizure-free (Engel class I), and one rarely has seizures (Engel class II). All seven patients had frequent seizures that led to IM: either daily (five patients) or 1-2 per week (two patients). The mean age (+/- standard deviation, SD) at seizure onset was 1.6 +/- 1.3 years (range 0.5-4 years). Etiologies were tuberous sclerosis (3 patients), trauma (1 patient), and unknown (3 patients). Mean age at surgery (+/- SD) was 4.1 +/- 2 years (range 1-7 years), and duration of epilepsy 2.5 +/- 1.1 years (range 0.5-4 years). Duration of IM was 11.7 +/- 5.6 days (5-19 days). Six patients had bilateral and one unilateral invasive electrodes. At last follow-up, four patients required fewer antiepileptic drugs (AEDs), one had the same medication but a higher dose, and two patients were taking additional AEDs. Follow-up was 30.6 +/- 9.5 months (range 19-41 months). Significance: Although uncommon, patients with TRE may improve after IM alone. The explanation for this observation remains unclear; however, perioperative medications including steroids, direct cortical manipulation, or other factors may influence the epileptogenic network

OBJECT: Techniques for the placement of intrathecal baclofen (ITB) systems have been described in detail, with special consideration given to complications from hardware placement. Risks including catheter kinking and migration, hardware erosion through the skin, and lumbar CSF leak are elevated given the often-low body mass index and poor nutritional status of this patient population. The bulk of a spinal catheter and fascial connector within the lumbar wound may increase the potential for the aforementioned risks, leading to potential risks for wound infection and breakdown. The authors' experience has led them to develop a novel method of paraspinal subfascial lumbar catheter placement to address these risks. The authors describe a novel lumbar intrathecal catheter placement technique as part of the ITB system. METHODS: All patients undergoing placement of an ITB system by the senior author at New York University Langone Medical Center between July 2010 and March 2011 underwent paraspinal subfascial lumbar catheter placement. Patients were followed-up by the surgeon 2 weeks after implantation and followed up and managed by their physiatrist thereafter, for an average of 5 months (range 0.5-9 months). Results Of the 20 patients who underwent this method of intrathecal catheter placement, none developed any hardware erosion, catheter migration, or CSF leak. One patient developed an abdominal wound infection 3 weeks after implantation, necessitating pump removal. CONCLUSIONS: In this initial short-term experience, subfascial placement of the lumbar spine intrathecal catheter may be an improvement over the traditional method of catheter placement. There is reduced risk of catheter migration or kinking, hardware erosion, CSF leak, and decreased operative time, all yielding a decreased reoperation rate in this vulnerable population.

OBJECT: Although rarely encountered, pediatric patients with severe cervical spine deformities and instability may occasionally require occipitocervicothoracic instrumentation and fusion. This case series reports the experience of 4 pediatric centers in managing this condition. Occipitocervical fixation is the treatment of choice for craniocervical instability that is symptomatic or threatens neurological function. In children, the most common distal fixation level with modern techniques is C-2. Treated patients maintain a significant amount of neck motion due to the flexibility of the subaxial cervical spine. Distal fixation to the thoracic spine has been reported in adult case series. This procedure is to be avoided due to the morbidity of complete loss of head and neck motion. Unfortunately, in rare cases, the pathological condition or highly aberrant anatomy may require occipitocervical constructs to include the thoracic spine. METHODS: The authors identified 13 patients who underwent occipitocervicothoracic fixation. Demographic, radiological, and clinical data were gathered through retrospective review of patient records from 4 institutions. RESULTS: Patients ranged from 1 to 14 years of age. There were 7 girls and 6 boys. Diagnoses included Klippel-Feil, Larsen, Morquio, and VATER syndromes as well as postlaminectomy kyphosis and severe skeletal dysplasia. Four patients were neurologically intact and 9 had myelopathy. Five children were treated with preoperative traction prior to instrumentation; 5 underwent both anterior and posterior spinal reconstruction. Two patients underwent instrumentation beyond the thoracic spine. Allograft was used anteriorly, and autologous rib grafts were used in the majority for posterior arthrodesis. Follow-up ranged from 0 to 43 months. Computed tomography confirmed fusion in 9 patients; the remaining patients were lost to follow-up or had not undergone repeat imaging at the time of writing. Patients with myelopathy either improved or stabilized. One child had mild postoperative unilateral upper-extremity weakness, and a second child died due to a tracheostomy infection. All patients had severe movement restriction as expected. CONCLUSIONS: Occipitocervicothoracic stabilization may be employed to stabilize and reconstruct complex pediatric spinal deformities. Neurological function can be maintained or improved. The long-term morbidity of loss of cervical motion remains to be elucidated.

Hydrocephalus caused by stenosis of the foramen of Monro is rare. The authors describe a 28-year-old female patient with bilateral foraminal stenosis treated using endoscopic septostomy and unilateral foraminal balloon plasty (foraminoplasty). The patient's hydrocephalus and symptoms resolved postoperatively. Endoscopic strategies may be employed as first-line therapy in this condition

PURPOSE: Intrathecal baclofen (ITB) therapy is an accepted treatment modality for spasticity and dystonia. Several complications related to ITB have been described, including mechanical malfunctions, infections, cerebrospinal fluid fistula, and baclofen withdrawal or overdose. In this study, we present our institutional experience with ITB therapy, emphasizing complication avoidance and lessons learned. METHODS: The charts of 87 patients treated with ITB therapy were retrospectively reviewed. The primary surgical technique, complication type and timing, method of treatment, and outcome were analyzed. RESULTS: Thirteen out of 76 (17.1%) patients primarily treated at our department had 25 complications. The first complication occurred 17.5-30.9 months (mean 24.2+/-6.7) after the pump implantation. Additional four patients with pumps placed elsewhere had six complications and were subsequently treated by our group. The main complications were: catheter fracture (11), subcutaneous fluid collection (5), lumbar wound/CSF infection (3), lumbar catheter or connector protrusion (3), pump malfunction (3), distal catheter migration outside the thecal sac (2), and baclofen withdrawal (1). Of the patients in the NYULMC group, six were treated by a single surgical procedure, six underwent multiple surgical procedures, and one was managed conservatively. In retrospect, changing the surgical technique, or adding an abdominal binder may have prevented 17 complications (54.8%). There were two deaths that were unrelated to the ITB therapy. CONCLUSION: ITB therapy is associated with complications, many of which require additional surgery. Some of these complications are avoidable by adhering to a strict surgical technique and a proper criterion for patient selection

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, has shown promise in treating recurrent adult high-grade glioma (HGG). However, there is very little data on recurrent or progressive pediatric HGG treated with bevacizumab. We report the results of a single institution experience using bevacizumab and irinotecan in children who relapsed or progressed following standard therapy. Twelve pediatric patients with recurrent or progressive HGG received bevacizumab at 10 mg/kg every 2 weeks with irinotecan at 125 mg/m(2). Magnetic resonance imaging (MRI) was performed prior to therapy and every 8 weeks subsequently. Ten patients had supratentorial HGG; 2 had DIPG. Radiological responses were defined according to MacDonald's criteria. Progression-free survival (PFS), overall survival (OS), and toxicities were analyzed. Ten (83.3%) patients tolerated bevacizumab without serious toxicity. Therapy was discontinued in 1 patient because of anaphylaxis. Another patient developed grade III delayed wound healing and deep vein thrombosis. Two patients (16.7%) experienced a partial response after the first MRI. No complete radiographic responses were seen. Stable disease was noted in 4 (33.3%) patients. The median PFS and OS were 2.25 and 6.25 months, respectively. A diffuse invasive recurrence pattern was noted in 5 (45.5%) patients. Treatment tolerance, toxicity, and recurrence profiles were comparable to adult HGG patients treated with bevacizumab. However, the radiological response rate, response duration, and survival appeared inferior in pediatric patients. Genetic differences in pediatric gliomas might account for this difference

Metameric lesions of the spine are rare. The authors present a case of patient with a complex metameric vascular lesion of the thoracic spine and describe a management strategy for this entity

OBJECT: The object of this study was to assess a multiinstitutional experience with pediatric occipitocervical constructs to determine whether a difference exists between the fusion and complication rates of constructs with or without direct C-1 instrumentation. METHODS: Seventy-seven cases of occiput-C2 instrumentation and fusion, performed at 9 children's hospitals, were retrospectively analyzed. Entry criteria included atlantooccipital instability with or without atlantoaxial instability. Any case involving subaxial instability was excluded. Constructs were divided into 3 groups based on the characteristics of the anchoring spinal instrumentation: Group 1, C-2 instrumentation; Group 2, C-1 and C-2 instrumentation without transarticular screw (TAS) placement; and Group 3, any TAS placement. Groups were compared based on rates of fusion and perioperative complications. RESULTS: Group 1 consisted of 16 patients (20.8%) and had a 100% rate of radiographically demonstrated fusion. Group 2 included 22 patients (28.6%), and a 100% fusion rate was achieved, although 2 cases were lost to follow-up before documented fusion. Group 3 included 39 patients (50.6%) and demonstrated a 100% radiographic fusion rate. Complication rates were 12.5, 13.7, and 5.1%, respectively. There were 3 vertebral artery injuries, 1 (4.5%) in Group 2 and 2 (5.1%) in Group 3. CONCLUSIONS: High fusion rates and low complication rates were achieved with each configuration examined. There was no difference in fusion rates between the group without (Group 1) and those with (Groups 2 and 3) C-1 instrumentation. These findings indicated that in the pediatric population, excellent occipitocervical fusion rates can be accomplished without directly instrumenting C-1

Patients with symptomatic Chiari malformation Type I (CM-I) typically exhibit a chronic, slowly progressive disease course with evolution of symptoms. However, some authors have reported acute neurological deterioration in the setting of CM-I and acquired Chiari malformations. Although brainstem dysfunction has been documented in patients with CM-II and hydrocephalus or shunt malfunction, to the authors' knowledge only 1 report describing ventriculoperitoneal (VP) shunt malfunction causing neurological deterioration in a patient with CM-I exists. The authors report on their experience with the treatment of previously asymptomatic CM-I in 2 children who experienced quite different manifestations of acute neurological deterioration secondary to VP shunt malfunction. Presumably, VP shunt malfunction created a positive rostral pressure gradient across a stenotic foramen magnum, resulting in tetraparesis from foramen magnum syndrome in 1 patient and acute ataxia and cranial nerve deficits from syringobulbia in the other. Although urgent shunt revisions yielded partial recovery of neurological function in both patients, marked improvement occurred only after posterior fossa decompression

Rhombencephalosynapsis (RES) is a rare congenital malformation of the cerebellum characterized by hypogenesis or agenesis of the vermis and fusion of the cerebellar hemispheres with or without fusion of the dentate nuclei and superior cerebellar peduncles. No genetic or chromosomal abnormalities have been identified for RES. Although the occurrence of RES is presumed to be sporadic, no clear pattern of inheritance has been identified. The authors report on a 17-year-old girl with autosomal dominant polycystic kidney disease Type 1 as well as RES