The impact of interventional neuroradiology on service in a neurosurgical unit.

Endovascular treatment of cerebral aneurysms has rapidly evolved and has transformed neurosurgical practice. We evaluated the influence of an interventional neuroradiology service on cerebral aneurysm management. We performed a retrospective analysis of all aneurysms treated in our unit before and after the establishment of endovascular treatment. All patients (n = 248: 78M: 170F aged 10-78 years) who underwent aneurysm treatment between 1996 and 1999 were included in the analysis. Length of in-patient stay on neurosurgical ward, GOS at 6-month follow-up and complications of treatment were the factors chosen for the analysis. Definitive treatment was attempted in 306 of 374 aneurysms detected (203 surgical and 103 endovascular). During the last 2 years of the study period, 46% of all aneurysms were coiled. Endovascular treatment of ruptured aneurysms tended to be sooner than surgery, but in-patient stay following treatment was the same. No significant difference in GOS at 6-month follow-up was found (chi2 = 0.18). Coiling of unruptured aneurysms reduced in-patient stay when compared with surgery (t-test, p < 0.001), fewer complications occurred, but no difference in outcome was seen at follow up (chi2 = 1.09). Our data suggest that the long-term morbidity following subarachnoid haemorrhage is not related to treatment modality. Coiling is the preferred treatment for unruptured aneurysms. The GOS is insensitive to the detection of the perceived benefits of coiling. The increasing role of interventional neuroradiology has direct effects on many aspects of neurosurgical practice.

The impact of interventional neuroradiology on neurosurgical training.

Aneurysmal subarachnoid haemorrhage carries a high mortality and morbidity. Surgical treatment (craniotomy and clipping of the aneurysm) has been, until recently, the gold standard treatment. Endovascular embolisation treatment has rapidly evolved and the evidence available suggests that the results are as good as surgery. Endovascular treatment successfully occludes the aneurysm to prevent re-haemorrhage, whilst reducing the procedural morbidity when compared to craniotomy and clipping. It is perceived to be of particular benefit for aneurysms in the posterior cerebral circulation where operative morbidity and mortality are significantly higher than for aneurysms on the anterior circle of Willis. The establishment of endovascular treatment has reduced the number of cases being treated surgically, and this has had a significant effect on surgical training. We analysed the management of all ruptured aneurysms treated in our unit over a 4-year period. During the same period, an endovascular service was established in the unit. We devised a novel system for the angiographic grading of aneurysms in order to evaluate the impact that coiling has had on surgical training. The results show that as few as four aneurysms per year would be appropriate for specialist registrars to operate upon. We propose some mechanisms for maintaining high quality surgical training.

Microvascular decompression for trigeminal neuralgia: report of outcome in patients over 65 years of age.

Microvascular decompression (MVD) is now recognized as an effective operation for the cure of trigeminal neuralgia (TN), and is far superior to the other surgical procedures utilized in the treatment of TN. TN is common in the elderly, but there is debate concerning MVD in 'elderly' patients. Some clinicians have a policy of not offering patients over a certain age the choice of MVD, yet the recurrence rate is inversely related to the age of the patient. Previous failed procedures and a long period of pain before MVD, also affect the outcome negatively. This study is a retrospective review of the outcome in elderly patients following MVD. Forty-two patients over the age of 65 years are reviewed after undergoing MVD for TN. The results indicate that there was no serious morbidity or mortality that could be ascribed to old age and the length of stay in the hospital was not influenced by the age of the patient. The results are compared with the outcome in a younger age group and the literature on MVD for TN reviewed.

Intracranial neoplasms in the first year of life: results of a second cohort of patients from a single institution.

The objective of this study was to describe the presentation and outcome of children with intracranial tumours under 1 year of age, and to compare the results with a previous cohort from the same paediatric neurosurgical unit. It is a retrospective review of all children under 1 year of age presenting with intracranial tumours between 1982 and 1997, with follow-up data from a multidisciplinary paediatric neuro-oncology clinic. Seventy-five children were diagnosed during the period of study. Overall survival at 5 years was 56% (31 of 55 eligible children), half of whom are in mainstream education. Earlier diagnosis and a dramatic reduction in peri-operative mortality compared to our previous cohort account for the improvements in the results of treatment for these children whose care can only be properly managed in a specialized paediatric oncology centre.

Spinal intradural tumours: Part I--Extramedullary.

Sixty-six patients had surgery for an intramedullary nerve sheath tumour under the care of one surgical team in a 16-year period. Surgery concentrated on radical intra- and extradural excision combined if necessary with vertebral column reconstruction. Ninety procedures were used in 35 males and 30 females with an age range 12-81 years. Forty-five per cent were located in the cervical, 26% in the thoracic and 29% in the lumbosacral region. Eighteen patients had NF1 and two patients NF2. Sixty-five per cent were schwannomas, 27% were mixed histology and 6% malignant. In terms of functional outcome, 37 patients improved by one or more Frankel grades, three deteriorated by one Frankel grade and no one who presented with symptoms alone deteriorated. There were no operative deaths; no instrumentation failures and five patients developed a CSF leak.

Spinal intradural tumours: Part II--Intramedullary.

The results of surgical management in 54 patients with intramedullary spinal cord tumours are presented. Cervical tumours were most frequent (25/54) followed by thoracic (16/54) and then lumbar (14/54). Ependymomas and astrocytomas were the most common tumour types. Total tumour removal was possible in just over half of the cases. Surgical complications included: two deaths, six patients with CSF leaks and one with wound infection. Postoperatively three patients had worsening of their motor deficit (unable to walk) and three patients had worsening of urinary sphincter function. Conversely, three patients who were unable to walk preoperatively were able to walk postoperatively, whilst four patients with sphincter disturbance showed improvement. Total tumour removal was not associated with increased risk of postoperative neurological deficit. Long-term follow up (2-18 years) was possible in 40 patients; 90% were still independently mobile. Our results compare favourably with other European studies and data from the North American units which have pioneered this surgery.

Bilateral ICP monitoring: its importance in detecting the severity of secondary insults.

The aim of head injury management is to prevent secondary insults to the damaged brain. Raised intracranial pressure and low cerebral perfusion pressure are two secondary insults which are important determinants of outcome following severe head injury (SHI). Traditionally ICP is measured in the right frontal region in an attempt to minimise the effects and complications of transducer placement. This assumes that the brain acts like a fluid and that ICP is transmitted equally throughout the intracranial space. Experimental studies suggest that this is not the case: expanding mass lesions are associated with the development of ICP gradients. Ten patients with SHI who had an unilateral mass lesion confirmed on CT were studied. All had bilateral placement of intraparenchymal Camino ICP transducers in the frontal regions. Data from both transducers were recorded every two minutes and stored electronically. The volume of the mass lesion was calculated from the CT scan. Significant and lasting ICP gradients between hemispheres were found in all patients with an acute subdural haematoma (greater than 10 mmHg for longer than 10 minutes). Such differences were not found in patients with intracerebral haematoma or contusions. We would advocate that ICP is recorded IPSILATERAL to the lesion in patients with SHI due to acute subdural haematoma.

Osteochondroma of the rib: an unusual cause of paraparesis.

A case of extradural spinal cord compression secondary to invasion of the spinal canal by a costal osteochondroma is reported. The literature relating to osteochondromas of the thoracic region is reviewed.

Cerebral oedema following intracerebral haemorrhage: the effect of the NMDA receptor antagonists MK-801 and D-CPPene.

The effects of pre-treatment with the NMDA receptor antagonists MK-801 and D-CPPene on the development of brain oedema were investigated in a rodent model of intracerebral haemorrhage. In acute experiments (4 hour survival) both drugs caused significant hypotension and had significant anaesthetic effects whilst conferring no protection against oedema formation. In chronic experiments (24 hour survival) MK-801 conferred no protection against brain oedema. With D-CPPene marginal protection against cortical oedema may have been conferred but this result should be interpreted with caution.

Primitive neuroectodermal tumour presenting with subarachnoid haemorrhage.

We report a case of medulloblastoma presenting as subarachnoid haemorrhage in an adult. The literature relating to subarachnoid haemorrhage and intracranial tumour is reviewed.

An evaluation of the camino ventricular bolt system in clinical practice.

The camino ventricular bolt system has been used to monitor intracranial pressure in patients after severe head injury. The correlation between the ventricular pressure measured with the Camino device and an external transducer showed that the Camino accurately measured intracranial pressure over a wide range, but that it read an average of 1.15 mm Hg higher than that obtained by the external transducer. The technique has the advantage over a remote transducer because it is sited within the ventricle. This may be of value in wave-form analysis.

The effect of immunosuppression on the development of cerebral oedema in an experimental model of intracerebral haemorrhage: whole body and regional irradiation.

The oedema which forms around an intracerebral haemorrhage has a complex aetiology. The immune response may have a role in its formation. There is clinical and experimental evidence that circulating leucocytes and platelets may mediate oedema formation. Global depletion of circulating leucocytes and platelets by whole body irradiation in a rodent model of intracerebral haemorrhage was found to confer protection against both ischaemia and oedema formation. This was not a direct effect of irradiation of the brain. The possible mechanisms for this protection are discussed.

Immunosuppression by whole-body irradiation and its effect on oedema in experimental cerebral ischaemia.

The effect of global immunosuppression by sublethal whole body X-irradiation on the development of cerebral oedema was assessed 24 h after right middle cerebral artery occlusion in the rat. Irradiation produced a significant leukopenia and thrombocytopaenia, and significantly reduced cortical oedema when compared to non-irradiated control animals.

Closed loop blood pressure control for cerebral perfusion studies.

A method is presented which maintains mean arterial blood pressure at predetermined values during cerebrovascular occlusion studies in a rat model. The system consists of a pressure measurement apparatus, a pump capable of infusing and withdrawing fluids, and a personal computer to control the infusion and withdrawal rate. An evaluation of the system is presented, and potential advantages and difficulties are discussed.

Cerebrospinal fluid rhinorrhoea associated with colloid cyst.

Three cases of non-traumatic cerebrospinal fluid (CSF) rhinorrhoea secondary to colloid cysts are presented. Non-traumatic CSF rhinorrhoea is rare and in only two previous reports has it been attributed to a colloid cyst.

The effect of immunosuppression with whole body and regional irradiation on the development of cerebral oedema in a rat model of intracerebral haemorrhage.

A lesion simulating intracerebral haemorrhage was produced in the right caudate nucleus of rats immunosuppressed with whole body or regional irradiation. Whole body irradiation produced significant leucopaenia and thrombocytopaenia and conferred protection against cerebral ischaemia and oedema when compared to nonirradiated control animals. Local radiation to the head or torso did not confer protection.

Approaches to preventing or reversing platelet alloimmunization using animal models.

Animal transfusion models were established to assess treatment programs for preventing or reversing platelet alloimmunization. Five control baboons given weekly transfusions of radiolabeled platelets from a single unrelated donor became immunized after an average of 2.4 +/- 2.1 transfusions. Similarly, 18 of 21 (86%) dogs given up to eight platelet transfusions from a single unrelated donor became immunized after an average of 2.3 +/- 1.7 transfusions. In six of seven baboons, prednisone or antithymocyte globulin alone or in combination effectively delayed platelet alloimmunization. In contrast, only two of 12 (17%) dogs given prednisone or antithymocyte serum (ATS) resisted alloimmunization. Neither splenectomy nor cyclophosphamide prevented alloimmunization in the baboon. In addition, attempts to reduce the immunogenicity of transfused platelets by inactivating the contaminating leukocytes with gamma radiation or by giving leukocyte-poor platelets were of no benefit in dogs. Reversal of platelet alloimmunization was achieved in two of three dogs treated with ATS and procarbazine hydrochloride. However, neither splenectomy, cyclophosphamide, ATS plus prednisone, nor vincristine sulfate produced any improvement. These studies show that the highly immunogenic nature of platelet transfusions in animals makes feasible the study of the prevention and reversal of platelet alloimmunization.