All permanent and fatal complications occurred during the authors' very early experience, indicating that a steep learning curve was associated with the procedure. Endoscopic third ventriculostomy, if performed correctly, is a safe, simple, and effective treatment option for various forms of noncommunicating hydrocephalus.

A prospective study of seven consecutive patients with congenital arachnoid cysts treated endoscopically is reported. The ages of the patients at the time of diagnosis ranged from 6 to 47 years with three patients under 15 years. Two cysts were located in the posterior cranial fossa, four in the middle cranial fossa, and one in the suprasellar-prepontine area. The patients' symptoms included headache, seizures, vomiting, nausea, dizziness, balance problems, and precocious puberty. The authors performed cystocisternostomies and ventriculocystostomies via burr holes with the aid of a universal neuroendoscopic system. Minor bleeding was easily controlled by rinsing. In one case, the endoscopic procedure had to be abandoned because of significant bleeding, which obscured a clear operative view, and an open microsurgical cyst fenestration was performed. The follow-up review periods in this group of patients ranged from 15 to 30 months. There was no mortality or morbidity. Symptoms were relieved in five patients and improved in one. Precocious puberty in one case continued. In six cases, follow-up magnetic resonance images or computerized tomography scans revealed a decrease in the size of the cysts. Although the follow-up period is too short to make statements on long-term outcome, the authors recommend the minimally invasive endoscopic approach for treatment of arachnoid cysts as the first therapy of choice. Should the endoscopic procedure fail, established treatment options such as microsurgical fenestration or cystoperitoneal shunting can subsequently be performed without causing additional risk to the patient.

The optimal treatment of thoracic and lumbar fractures remains controversial. While many authors recommend dorsal instrumentation with an internal fixator, others favour an anterior approach. To evaluate the posterior approach and to identify conditions under which an anterior approach should be preferred, 133 patients with unstable thoracic and lumbar fractures of the spine who underwent dorsal instrumentation with an internal fixator were analyzed. Clinical data were recorded prospectively with respect to fracture type, neurological findings, operative complications, spinal deformation correction, and long-term outcome. All fractures were located between the 7th thoracic and the 5th lumbar vertebrae and were considered to be unstable with respect to the three column model. Seventy-six patients (57%) received surgery within the first seven days after the trauma. Postoperatively, 98% of patients with a radicular lesion or an incomplete transverse syndrome (47 patients, 35%) improved. Stable fracture consolidation after fixator removal was obtained in 98% (130 of 133 patients). The preoperative kyphosis angle decreased from an average of 10.1 degrees to 7.4 degrees at the three year follow up. Major operative complications consisted of two isolated nerve root lesions (1.5%), two deep wound infections with need of fixator removal (1.5%), and mallocation of two pedicle screws with need for another procedure in two patients (1.5%). Three patients (2%) suffered from insufficient bony fusion with increase of kyphotic deformation and required subsequent anterior stabilization. These three patients presented with an initial kyphosis or wedge angle of 20 degrees or higher. In conclusion, dorsal stabilization with the internal fixator is a safe and reliable treatment for unstable fractures of the lower thoracic and lumbar spine. The authors recommend this procedure because of its low-invasiveness in conjunction with satisfactory reconstruction and stabilization. However, an anterior approach should be considered in fractures with initial kyphotic deformation or wedge angle of 20 or more degrees.

We report a fatal tumor hemorrhage in a 1-and-a-half-year old girl after ventriculoperitoneal shunting for obstructive hydrocephalus caused by a thalamic tumor. The possible pathophysiological mechanism is briefly discussed and the literature is reviewed.

An infrared-based neuronavigation device (Surgical Microscope Navigator) integrating a pointer system with microscope guidance, is presented. We report our experience with this system in 17 patients undergoing surgery for space-occupying lesions of the central region. Cortical motor stimulation was additionally used in selected cases. The system was helpful in all operations by guiding craniotomy, corticotomy, or extent of tissue resection. Gross total tumor removal was possible in all patients but 1. Technical problems occurred in 1 case. Postoperative neurological worsening was found in 3 patients; this was reversible within a few weeks in 2 of them. In 9 cases, neuronavigation (combined with cortical stimulation, if necessary) probably prevented permanent neurological injury by exactly localizing tumors in the central area. It is concluded that neuronavigation (combined with motor cortex stimulation) may decrease neurological injury or neurosurgical invasiveness in lesions of the central region.