Faculty Bibliography

Intrinsic brain stem tumors are a heterogeneous group of neoplasms that may be classified according to clinical and neurodiagnostic criteria. We have described simple anatomic categories that include focal, diffuse, cystic, and cervicomedullary tumors. Although there is no surgical option for the common diffuse brain stem neoplasms, the other tumors may be operated on if the clinical and neurodiagnostic assessment suggests the possibility of a benign neoplasm. It is important to emphasize that although all tumors that were covered by intact ependyma or pia were considered intrinsic tumors in this series, most of these tumors created a 'bulge' that was obvious on visual inspection of the external surface of the brain stem. In all of the tumors that were benefitted by surgery, the neoplasms tended to 'bulge' from the brain stem rather than infiltrate it, which was the case with the diffuse neoplasms. It seems likely that many of the focal, cystic, and cervicomedullary tumors are similar to the dorsal exophytic brain stem tumors, which are characteristically low-grade astrocytomas that disrupt the ependymal lining and grow posteriorly into the fourth ventricle. Although surgery has been well tolerated and beneficial in many patients, it would be premature to comment on the duration of remission or the possibility of permanent cure

The authors review their experience in the management of 22 patients with hydromyelia over a 26-month period. Ten children had Chiari I malformations and hydromyelia; 4 children had myelomeningoceles (3 with large thoracic spinal cord cavitations and 1 with cervical hydromyelia); 6 children had distal hydromyelia associated with tethered cords and occult dysraphism; and 2 patients had cavitation subsequent to arachnoiditis. All patients were investigated preoperatively with MRI and intraoperatively with ultrasound. These neurodiagnostic examinations dictated the type of surgical intervention. Patients with Chiari I or Chiari II malformations, cervical hydromyelia, or basal arachnoiditis underwent decompression of the hindbrain malformations, myelotomy with drainage of the cyst, and placement of a stent. When the area of hydromyelia extended to the obex, as demonstrated by intraoperative ultrasound, the obex was plugged. Cyst-pleural shunts were placed in the children who had myelomeningoceles and thoracic hydromyelia. Patients with distal hydromyelia underwent modified terminal ventriculostomy. The classical presentation of brachial amyotrophy and dissociated sensory loss was present in only 3 patients. Progressive scoliosis without neurological deficit, pain, and Lhermitte's phenomenon were common presentations. The patients with tethered cords were generally asymptomatic from their cysts. The authors discuss operative technique, utilization of intraoperative ultrasound, and surgical outcome

The authors review their experience with the operative management of 19 consecutive cases of malignant astrocytoma of the spinal cord. There was a male to female ratio of 1.1:1, and the median age of the population was 14 years (range 1 to 32 years). The median duration of symptoms prior to definitive diagnosis was 7 weeks. Radical excision was carried out in all cases, with 18 patients (95%) receiving radiotherapy and 10 patients (53%) receiving chemotherapy as well. To date, 15 (79%) of the 19 patients in this series have died, with a median survival period of 6 months following surgery. No patient improved after operation. Hydrocephalus was present in 11 patients (58%), seven of whom underwent ventricular shunting procedures. Dissemination of disease was found in 11 patients (58%). Extraneural metastases did not occur in the absence of a ventricular shunt. The authors conclude that malignant astrocytomas of the spinal cord are heralded by a short history followed by rapid neurological deterioration and usually death. The rationale for operation is discussed, and an aggressive approach utilizing adjuvant therapy directed at the entire neuraxis is suggested

To determine the current neurosurgical treatment of children with medulloblastomas, we reviewed the operative reports and neurosurgical report forms from 141 children with posterior fossa medulloblastomas treated on two current Children's Cancer Study Group (CCSG) protocols, CCG-921 for high-stage and CCG-923 for low-stage medulloblastoma. Most medulloblastoma operations were performed in major medical centers: 61% of the operations were performed in CCSG member institutions, 23% in CCSG affiliates and 16% in other institutions. The tumor T stage distribution was as follows: T1-4%, T2-15%, T3A-35%, T3B-36%, and T4-10%. Tumors infiltrated the brainstem in 38% of cases and were associated with hydrocephalus in 91% of cases. Hydrocephalus was managed by external ventricular drains in 50% and by shunts in 60%. Adjunctive instruments (e.g., microscope, ultrasonic aspirator) were used in 93% of the operations. Tumor removals were as follows: biopsy only 3%, partial removals 13%, subtotal removals 13%, near total removals 41% and gross total removals in 40%; 90% or more of the tumor was removed in 81% of the operations. Forty-seven percent of the operations were performed by pediatric neurosurgeons. Near total and gross total removals were performed significantly more often (p less than 0.05) by pediatric neurosurgeons than by general neurosurgeons. Postoperative morbidity was reported in 46% of cases, including neurologic morbidity in 26% of cases. There was no significant difference in patient morbidity between pediatric and general neurosurgeons