High-resolution three-dimensional magnetic resonance angiography and three-dimensional spoiled gradient-recalled imaging in the evaluation of neurovascular compression in patients with trigeminal neuralgia: a double-blind pilot study.

OBJECTIVE: To assess the value of high-resolution three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography and gadolinium (Gad)-enhanced 3D spoiled gradient-recalled imaging in the visualization of neurovascular compression in patients with trigeminal neuralgia. METHODS: Forty-eight patients with unilateral trigeminal neuralgia underwent high-resolution 3D TOF MR angiography. After administration of a contrast agent, a 3D spoiled gradient-recalled sequence (3D Gad) was run. Images were reviewed by a radiologist blinded to clinical details. All patients underwent microvascular decompression surgery. Microdissection of the trigeminal nerve and compressing vessels was videotaped during surgery and reviewed by surgeons uninvolved in patient care. Results from neuroradiological studies were then compared with findings on operative videotapes. RESULTS: MR angiography in combination with 3D Gad imaging identified surgically verified neurovascular contact in 42 of 46 (91%) symptomatic nerves. The offending vessel (artery, vein) was correctly identified in 31 of 41 cases (sensitivity, 76%; specificity, 75%). Neurovascular compression was observed in 71% of asymptomatic nerves with a trend toward greater compression severity on the symptomatic nerve (P < 0.09). Agreement between the direction of neurovascular contact defined by 3D TOF MR angiography and 3D Gad and findings at surgery was good (kappa = 0.78; 95% confidence interval, 0.61-0.94). CONCLUSION: Double-blind assessment of surgical and neuroradiological findings confirms that neurovascular compression can be visualized with good sensitivity in patients with trigeminal neuralgia by 3D TOF MR angiography in combination with Gad-enhanced 3D spoiled gradient-recalled sequences. Anatomic relationships defined by this method can be useful in predicting surgical findings.

A single-pass tunneling technique for CSF shunting procedures.

Implantation of ventriculoperitoneal shunts in the precoronal position is generally accomplished using a retroauricular incision for subcutaneous tunneling. Retroauricular incisions can be associated with complications, including cerebrospinal fluid leak and shunt infection. We describe a technique for 'single-pass' shunt tunneling from frontal to abdominal incisions and our initial results in a consecutive, prospective series of 15 children (age 2 days to 5 years). Eleven patients presented with congenital hydrocephalus (including 5 with myelomeningocele and 3 with posthemorrhagic hydrocephalus) and 4 with hydrocephalus secondary to central nervous system (CNS) tumors. The average length of clinical follow-up was 6 months (range 1-13 months). There were no perioperative or long-term complications of the single-pass technique. Nine of the 11 patients with congenital hydrocephalus are currently well without any further medical or surgical intervention. Two underwent shunt revision for proximal obstruction, with an intact distal system. Three of the 4 patients with hydrocephalus secondary to CNS tumor suffered secondary shunt complications during periods of severe neutropenia resulting from chemotherapy (6 weeks to 6 months after shunt insertion). For primary ventriculoperitoneal shunt insertion in infants and young children, the single-pass tunneling technique is safe and avoids one source of complications.

Ultrasonographic screening in infants with isolated spinal strawberry nevi.

OBJECT: The authors performed spinal ultrasonography and/or magnetic resonance (MR) imaging in 20 consecutive newborns with spinal strawberry nevi. METHODS: In 15 patients the strawberry nevi were isolated and in five they were associated with other cutaneous markers of occult spinal dysraphism (OSD). In four of five patients with additional cutaneous markers, but in none of those without, MR imaging and surgical exploration demonstrated OSD. The authors found that strawberry nevi in isolation do not appear to indicate underlying dysraphic states. The sparse clinical literature on this topic, which is reviewed, confirms an association between OSD and strawberry nevi presenting in conjunction with other cutaneous signatures. By contrast, spinal strawberry nevi occurring alone may not indicate the presence of underlying dysraphism. CONCLUSIONS: A prospective study of larger numbers of patients with isolated strawberry nevi, undergoing MR imaging evaluation, is necessary to determine whether neuroimaging screening in these patients is indicated.