Wolfgang Seeger

The dorsolateral, suboccipital, transcondylar approach to the lower clivus and anterior portion of the craniocervical junction.

The authors review their experience with a dorsolateral approach to the anterior rim of the foramen magnum and adjacent region. The operative technique includes exposure of the vertebral artery at C1, partial resection of the occipital condyle and lateral atlantal mass, and extradural drilling of the jugular tubercle. This approach has been applied in six patients who harbored intradural space-occupying lesions located ventral to the lower brain stem. Excision of the neoplasm was virtually total in all but one patient, in whom biopsy was the primary goal of the intervention. No morbidity and no mortality were associated with this approach. The main advantage of the dorsolateral, suboccipital, transcondylar route is the direct view it offers to the anterior rim of the foramen magnum without requiring brain stem retraction.

Microsurgery of deep-seated cavernous angiomas: Report of 26 cases

SummaryThe authors review 26 patients with deep-seated cavernous angiomas which were removed by microsurgery. Ten of the angiomas were located in the insula and basal ganglia, 2 in the thalamus, 5 in the midbrain, 8 in the pons, and 1 in the brachium pontis. The patients were among 73 consecutive cases operated on between August 1983 and December 1989 for symptomatic cavernous angiomas in various locations.In 11 cases total excision of the cavernoma was achieved without producing additional neurological deficits. Postoperative neurological recovery was delayed in 7 patients. In the remaining 8, the complicated postoperative course was caused by bleeding from residual parts of the malformation or damage to long-tract pathways in two cases, respectively, vascular injury during dissection in three cases, and paradoxical air embolism in one case. In order to achieve a satisfactory surgical result, it is stressed that particular attention has to be paid to the operative approach, to careful dissection and complete removal of the malformation, to perforating arteries, and to anomalous venous drainage.

Cerebrospinal fluid shunting in idiopathic normal-pressure hydrocephalus of the elderly: effect of periventricular and deep white matter lesions.

OBJECTIVE We investigated the effect of periventricular and deep white matter lesions (DWMLs) on outcome after cerebrospinal fluid shunting in a prospective series of elderly patients with idiopathic normal-pressure hydrocephalus. METHODS White matter lesions were assessed with T2-weighted magnetic resonance scans according to a standard protocol in 41 patients with idiopathic normal-pressure hydrocephalus of the elderly who underwent subsequent shunting. In all patients, the diagnosis of idiopathic normal-pressure hydrocephalus had been established preoperatively by clinical and diagnostic investigations. RESULTS At a mean follow-up of 16 months, clinical improvement was observed in 37 of 41 patients (90%). There was no persistent morbidity related to surgery. The degree of overall clinical improvement was negatively correlated with the extension of periventricular lesions (correlation coefficient r = -0.324 [P = 0.04]) and DWMLs (correlation coefficient r = -0.373 [P = 0.02]). This negative correlation was also noted when the analysis was conducted separately for each of the cardinal symptoms (gait disturbance, cognitive impairment, and urinary incontinence). There was no consistent pattern of periventricular and DWMLs in the four patients who failed to respond to shunting. CONCLUSION Periventricular and DWMLs of varying degrees are common findings on magnetic resonance scans of patients with idiopathic normal-pressure hydrocephalus of the elderly. After careful preoperative selection of patients with idiopathic normal-pressure hydrocephalus, individuals with DWMLs suggestive of concomitant vascular encephalopathy may also benefit from cerebrospinal fluid diversion. Although, in general, the degree of improvement depends on the severity of periventricular and DWMLs, patients with more extensive WMLs still may derive clinical benefit from the operation.

The relation of intracranial pressure B-waves to different sleep stages in patients with suspected normal pressure hydrocephalus

SummaryThe interpretation of data from continuous monitoring of intra-cranial pressure (ICP) in patients with suspected normal pressure hydrocephalus (NPH) is the subject of controversy. Despite the fact that overnight ICP monitoring is widely used for the diagnosis of NPH, normative criteria are poorly defined. The present study demonstrates that there is a relationship between the relative frequency, the absolute amplitude, the wavelength and the morphology of B-waves and different sleep stages.Intraventricular intracranial pressure was recorded continuously overnight in 16 patients with suspected normal pressure hydrocephalus. Simultaneous polysomnography was performed to investigate the relation of spontaneous ICP oscillations to different sleep stages. A correlative analysis was done with the data of 13 patients. Three patients were excluded, one who was awake throughout the night and two in whom polysomnography was incomplete due to technicai reasons. The mean resting cerebrospinal fluid (CSF) pressure was 12.87 cm CSF. B-waves were observed in the ICP recordings of all patients. They were present for a mean of 72% of the total recording time. The relative frequency of B-waves was higher during REM sleep and sleep stage 2 as compared to wakefulness (87.8% and 83.2% vs. 56, p < 0.05). The absolute amplitude was higher during REM sleep than in wakefulness (9.56 vs. 3.44 cm CSF, p < 0.05). Wavelengths were longer in REM sleep than in wakefulness and stages 1 and 2 (62.4 vs. 42, 40.7 and 44.8 sec, p < 0.05). The morphology of B-waves was also related to different sleep stages. Ramp-type B-waves were associated with REM sleep in six patients, however, were also present in sleep stage 2 in three of them.Knowledge of the relation of spontaneous ICP oscillations to different sleep stages may help to establish physiological foundations and alterations. Furthermore, polysomnography may be useful to avoid erroneous interpretation of ICP recordings due to sleep stage related variability.

Parkinsonism and rest tremor secondary to supratentorial tumours sparing the basal ganglia.

SummaryIntracranial neoplasms are an uncommon cause of symptomatic Parkinsonism and rest tremor. We found an incidence of 0.3% in a prospective evaluation of 907 patients with supratentorial tumours. Eight patients with Parkinsonism and rest tremor secondary to supratentorial tumours sparing the basal ganglia are reported.Neuro-imaging revealed compression and distortion of the basal ganglia by large tumours which were identified histopathologically as meningiomas in four patients and as an epidermoid, a fibrillary astrocytoma, an anaplastic oligodendroglioma and a glioblastoma.Six patients underwent tumour removal by craniotomy, in two the histopathology was obtained by stereotactic biopsy. Four patients were free of Parkinsonian symptoms and signs on long-term follow-up.The possible pathophysiological mechanisms involved are discussed. Since some of these patients closely resemble cases of idiopathic Parkinsons disease, and the movement disorder can precede other symptoms and signs or will remain isolated in the further course, the diagnosis of an intracranial neoplasm was generally delayed in these patients. Increased awareness of this rare entity may lead to an earlier diagnosis. Early computed tomography in patients with Parkinsonism might help to detect these patients with a potentially curable cause of their condition.

Microsurgical Management of Ventral and Ventrolateral Foramen Magnum Meningiomas

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the microanatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

Experience with the infratentorial supracerebellar approach in lesions of the quadrigeminal region, posterior third ventricle, culmen cerebelli, and cerebellar peduncle.

SummaryWe report about our experience with the infratentorial supracerebellar approach in 23 patients operated on for lesions located in the posterior part of the third ventricle, quadrigeminal plate, culmen cerebelli and cerebellar peduncle.Three patients had transient worsening of their deficits immediately after surgery. Three patients developed haemorrhages post-operatively requiring surgical evacuation. One of them died.None of the patients developed specific complications which could without any doubt be attributed to the approach. We concluded that in combination with intra-operative CSF drainage and the sitting position the infratentorial supracerebellar approach allows safe access to lesions situated in an area limited by the posterior part of the third ventricle, the fastigium level and both cerebellar peduncles.

Unilateral microsurgical approaches to extramedullary spinal tumours: Operative technique and results

SummaryThe operative technique of limited approaches to extramedullary spinal tumours is described. The results after unilateral approaches are as satisfying as after standard laminectomies. The rationale of attempting an unilateral approach is to avoid damage to the dorsal static structures of the vertebral column. Access given by limited approach and possibilities of enlarging the bony defect depending on the topographical situation of the tumour are discussed in detail. It is emphasized that the dura should be opened only over the tumour in order to avoid protrusion of the cord.

Extended pterional decompression of the orbit: An alternative treatment in endocrine orbitopathy

Extended pterional decompression was performed in seven orbits. The indication was optic neuropathy in six orbits and corneal ulceration in one. As compared to ethmoidectomy, advantages of the pterional approach seem to be the preservation of the motility of the eye and the lack of paranasal sinus complications. We consider the pterional approach to be appropriate for decompression of endocrine orbitopathies that do not respond to conservative measures.

Compressive Optic Nerve Lesions at the Optic Canal

1 Introduction.- 2 A Narrow Passage - Anatomic Considerations Topography of the Optic Canal Representing a Predilection of Nerve Compression with Various Pathologic Conditions.- 3 The Clinical Signs and Symptoms of Optic Nerve Compression and Clinical Disease Entities Masking Compressive Lesions.- 3.1 Ophthalmoscopic Findings. Visual Loss, Visual Field Defects, Afferent Pupillary Defect, Color Vision.- 3.2 Visual Evoked Potentials in Optic Nerve Compression.- 4 The Concept of Optic Nerve Compression by Dolichoectatic Arteries Revisited. The Literature and Why It Became Forgotten.- 5 Pneumosinus Dilatans - Rarely Diagnosed and Poorly Understood.- 6 CT Findings of Compressive Lesions at the Optic Canal.- 7 Pterional Approach for Microsurgical Decompression of the Optic Nerve.- 8 Intraoperative Findings in Patients with Intracanalicular Optic Nerve Compression.- 9 Selected Case Reports.- 10 Conclusions.- References.