Achondroplasia and cervicomedullary compression: prospective evaluation and surgical treatment.

The association between sudden death and cervicomedullary compression in infants with achondroplasia has been well described. Prospective clinical and imaging evaluations have been recommended to identify those infants with achondroplasia who are at risk of dying suddenly from respiratory arrest secondary to unrecognized cervicomedullary compression. Since 1988, we have prospectively evaluated 11 infants (average age 13 weeks) with achondroplasia who were asymptomatic for cervicomedullary compression on initial clinical evaluation. Craniocervical magnetic resonance imaging (MRI) findings included narrowing of the foramen magnum, effacement of the subarachnoid spaces at the cervicomedullary junction, abnormal intrinsic cord signal intensity and mild to moderate ventriculomegaly. Two patients with severe cord compression underwent immediate decompression. Two patients developed opisthotonic posturing within 3 months of evaluation and underwent foramen magnum decompression, including suboccipital craniectomy and atlantal laminectomy. Surgery in all cases revealed forward extension of the squamous portion of the occipital bone, thickened posterior rim of the foramen magnum and a dense fibrotic epidural band. There were no complications from surgery. Seven patients did not require surgery and were followed closely. All 11 patients remain asymptomatic at follow-up (mean 4.6 years; range 16 months to 7.3 years), and no patient has required a diversionary shunt procedure. The results of this prospective study confirm that early clinical and MRI evaluations are necessary to determine whether infants with achondroplasia have cervicomedullary compression. With early recognition, an immediate decompression can be performed safely to avoid serious complications associated with cervicomedullary compression, including sudden death.

Dural sinus thrombosis and pseudotumor cerebri: unexpected complications of suboccipital craniotomy and translabyrinthine craniectomy.

OBJECT: The goal of this study was to document the hazards associated with pseudotumor cerebri resulting from transverse sinus thrombosis after tumor resection. Dural sinus thrombosis is a rare and potentially serious complication of suboccipital craniotomy and translabyrinthine craniectomy. Pseudotumor cerebri may occur when venous hypertension develops secondary to outflow obstruction. Previous research indicates that occlusion of a single transverse sinus is well tolerated when the contralateral sinus remains patent. METHODS: The authors report the results in five of a total of 107 patients who underwent suboccipital craniotomy or translabyrinthine craniectomy for resection of a tumor. Postoperatively, these patients developed headache, visual obscuration, and florid papilledema as a result of increased intracranial pressure (ICP). In each patient, the transverse sinus on the treated side was thrombosed; patency of the contralateral sinus was confirmed on magnetic resonance (MR) imaging. Four patients required lumboperitoneal or ventriculoperitoneal shunts and one required medical treatment for increased ICP. All five patients regained their baseline neurological function after treatment. Techniques used to avoid thrombosis during surgery are discussed. CONCLUSIONS: First, the status of the transverse and sigmoid sinuses should be documented using MR venography before patients undergo posterior fossa surgery. Second, thrombosis of a transverse or sigmoid sinus may not be tolerated even if the sinus is nondominant; vision-threatening pseudotumor cerebri may result. Third, MR venography is a reliable, noninvasive means of evaluating the venous sinuses. Fourth, if the diagnosis is made shortly after thrombosis, then direct endovascular thrombolysis with urokinase may be a therapeutic option. If the presentation is delayed, then ophthalmological complications of pseudotumor cerebri can be avoided by administration of a combination of acetazolamide, dexamethasone, lumbar puncture, and possibly lumboperitoneal shunt placement.

Endoscopic treatment of loculated hydrocephalus.

Loculated hydrocephalus remains a difficult neurosurgical problem and endoscopes designed to navigate through the ventricular system provide a new option for treatment. The authors review their experience, during the period March 1990 to June 1993, using a steerable fiberscope in 34 cases of loculated hydrocephalus to evaluate the efficacy of endoscopic cyst fenestration. The goals of treatment were to control hydrocephalus, simplify preexisting shunt systems, and reduce operative morbidity. Endoscopic cyst fenestrations reduced the shunt revision rate from 3.04 per year prior to endoscopy to 0.25 per year after the procedure, during a follow-up period ranging from 8 to 45 months, mean 26 months. However, eight patients (23.5%) required 14 repeat operations to control loculated hydrocephalus. After endoscopy, patients with multiloculated hydrocephalus had a nearly fivefold increased risk (relative risk 4.85) for shunt malfunction and more than a twofold increased risk (relative risk 2.43) for cyst recurrence versus patients with uniloculated hydrocephalus. Similarly, six (50%) of 12 patients shunted prior to endoscopy required a repeat endoscopic procedure (relative risk 5.56). Although repeat endoscopic procedures may be required to control hydrocephalus, endoscopic cyst fenestration avoided placement of a shunt in seven (33%) of 21 patients with uniloculated hydrocephalus. One patient, encountered early in the authors' experience, required a craniotomy for fenestration of multiple ventricular cysts. Endoscopic complications included cerebrospinal fluid leakage in one case and ventriculitis in another. The authors conclude that endoscopic treatment of loculated hydrocephalus is a safe, minimally invasive technique that should be considered as the initial treatment option.

Nonglucocorticoid-induced lumbar epidural lipomatosis: a case report and review of literature.

A case of nonglucocorticoid-induced lumbar epidural lipomatosis in a middle-aged black woman with neurogenic claudication is presented. The etiology, diagnosis, management, and outcome are discussed in detail.