A series of 80 cases of medulloblastomas in children undergoing operation and postoperatively followed between 1980 and 1990 at Great Ormond Street Hospital for Children (GOSH) has been reviewed and compared to an earlier series reported from the same institution by McIntosh. The overall 5-year survival rate for the present series was 50%, although three patients died after surviving 5 years. The operative mortality rate was 5%. Survival analysis revealed that the presence or absence of spinal metastases and the necessity for some form of cerebrospinal fluid diversion within 30 days of the operation independently significantly affected survival in this series. Those patients with no spinal metastasis and total tumor removal had a 5-year survival rate of 73%, making this the most favorable subgroup in the series. Patient age and gender, duration of symptoms, Chang T stages, tumor volume, extent of resection, and postoperative chemotherapy were not significant variables. Although these results are better than those reported in the earlier GOSH series, they are not significantly different from the results of the second 5-year cohort of patients described in that article. Radiotherapy remains the greatest advance in treatment, although it is hoped that further improvement will result from the various chemotherapy protocols now being studied and from increasing knowledge of the biological behavior of these tumors.

Our results and those of others suggest that all such cysts are ganglion cysts that derive from either the AF or the PLL at the disc level. Although disc cysts might be AF ganglion cysts exhibiting disc communication, their separate distinction is probably unnecessary. Cystectomy alone affords complete symptomatic remission; discectomy is usually unnecessary. Although anticipated with ganglia in general, neither spontaneous resolution nor postoperative recurrences have been witnessed. Unlike ganglia in general or juxtafacet ganglion cysts, such cysts seem to be unusually restricted to young men.

Obstructive hydrocephalus complicating foramen magnum decompression (FMD) for a Chiari malformation (CM) Type I is rare. Two female patients (17 and 55 years old) presented with strain-related headaches. In both cases magnetic resonance (MR) imaging studies confirmed a CM Type I, which was accompanied by syringomyelia in one case. Both patients underwent uncomplicated FMD with good initial recovery. Unfortunately, conditions in both patients deteriorated, with severe headaches occurring between Days 5 and 6 post-FMD. Decreased consciousness occurred in one case. In both patients, computerized tomography scanning demonstrated an acute obstructive hydrocephalus associated with bilateral infratentorial extraaxial fluid collections (EAFCs). In addition, left parafalcine and convexity EAFCs were present in one case. An emergency external ventricular drain was required in one patient, with delayed conversion to a ventriculo-peritoneal shunt. Spontaneous resolution occurred in the other patient without neurosurgical intervention. In both cases, MR imaging confirmed that each EAFC was subdural, resembled cerebrospinal fluid (CSF), and had distorted the superior cerebellum anteroinferiorly. Despite upper fourth ventricle/aqueduct compromise in one case, normal aqueduct flow artifacts were apparent on examination. All EAFCs resolved spontaneously. Obstructive hydrocephalus complicating FMD is rare but invariably associated with infratentorial EAFCs, which were confirmed to be subdural hygromas in this report. The authors assert that hydrocephalus results from upper fourth ventricle/aqueduct compromise as a result of CSF subdural dissection following a pinhole arachnoid tear on durotomy. Because such hygromas spontaneously resolve, permanent shunt insertion should be avoided.

Object. Atlantoaxial rotatory fixation (AARF) is an uncommon disorder of childhood in which resolution usually occurs spontaneously or after traction therapy. In a minority of children irreducible or chronic fixation develop, and the natural history then usually involves restriction of head on neck movement, abnormal head position, and progressive facial asymmetry. The conventional management in these cases has been a posterior fusion. Methods. The authors performed an open reduction via the extreme-lateral approach without adjunctive fixation surgery in 13 children who ranged in age from 4 to 11 years. Postoperatively, halo jacket therapy was undertaken for 8 to 12 weeks. There were no neurological complications despite damage to one vertebral artery and one wound infection. Functional outcome was assessed after a minimum of 24 months (range 29–72 months). Facial asymmetry markedly improved. Sagittal movements were similar to those observed in control individuals. Axial rotation, although reduced compared with that in controls, was present but usually asymmetrical. Conclusions. In the authors' opinion, open reduction provides the best possibility of normal facial development and return of axial movement in cases of AARF.