The role of endoscopic biopsy and third ventriculostomy in the management of pineal region tumours.

The best surgical strategy for treating patients with pineal tumours presenting with acute hydrocephalus remains undermined. During the past 17 years we have used transventricular endoscopic biopsy and third ventriculostomy as a one-step procedure in the initial management of these cases, and present the largest consecutive case series illustrating the value of this technique. We have successfully managed 34 consecutive patients with pineal region tumours, carrying out third ventriculostomy in 18 patients. Histological diagnosis was obtained in 32/34 (94%) of the cases. There were no deaths or major complications and only one patient required a ventriculo-peritoneal shunt owing to ventriculostomy failure. According to current management protocols and depending on histology, tumours were treated by a combination of resection via craniotomy followed by radiotherapy or chemotherapy, or by the latter therapies alone. This one step procedure is minimally invasive and safely achieves adequate biopsy with control of hydrocephalus, whilst definitive histology and biochemical marker studies are obtained. Definitive treatment for each tumour is designed according to diagnosis.

Human area V5 and motion in the ipsilateral visual field.

We have studied area V5 of the human brain with visually-evoked potential (VEP) and functional magnetic resonance imaging (fMRI) methods, using hemifield motion stimuli. Our results confirmed the presence of an ipsilateral field representation in V5 and found: (i) a delay in the ipsilateral response in V5, irrespective of the hemifield stimulated; (ii) a longer ipsilateral delay for left hemifield than for right hemifield stimulation; and (iii) in a patient with a section of the splenium, an absent ipsilateral response for right but not left hemifield stimulation. Together with neurophysiological and anatomical evidence in the monkey, our non-invasive spatial and temporal imaging studies in man reveal that ipsilateral V5 is activated by motion signals transferred from contralateral V5. The asymmetry of ipsilateral delay in normal subjects and the asymmetrical loss of ipsilateral response following splenial section imply that signals related to visual motion are transferred from one V5 to the other through two segregated pathways.

An analysis of neuropsychological change scores following selective temporal resection of the non-dominant temporal lobe.

Reliable change in neuropsychological test scores was examined in patients undergoing right-sided, selective temporal resections for the relief of intractable epilepsy. Measures were taken prior to surgery, 1-month post-operatively and 1-year post-operatively. Non-verbal memory performance was more robustly measured than in previous studies. Results failed to replicate previous studies which report verbal memory deficits even following right-sided surgery. No strong evidence of a material-specific, non-verbal memory deficit was found on commonly used tests of non-verbal memory. The majority of patients failed to show reliable decline in performance following surgery indicating that fears of post-operative memory decline may be unfounded.

Accumulation of p53 and Ki-67 expression do not predict survival in patients with fibrillary astrocytomas or the response of these tumors to radiotherapy.

OBJECTIVE: Although radiotherapy is often used in the treatment of patients with low-grade astrocytomas, its value is still uncertain. Radiotherapy carries a risk of morbidity for patients and has time and cost implications for health services. We have assessed the value of two histological variables, p53 accumulation and Ki-67 expression, in predicting the response of astrocytomas to radiotherapy. The former antigen was assessed because many astrocytic tumors show mutations in the p53 gene, the function of which is crucial for mediating cell death after radiotherapy, and the latter was assessed because it is expressed only in proliferating tumor cells, which may show greater radiosensitivity than nonproliferating cells. METHODS: Immunohistochemistry was used to detect the accumulation of p53 and expression of Ki-67 in a retrospective series of 96 patients with supratentorial fibrillary astrocytomas, 58 of whom had received postoperative radiotherapy. The immunohistochemical data were correlated with survival after radiotherapy. RESULTS: There was no significant difference in survival between the patients who did and those who did not receive radiotherapy. The p53 and Ki-67 labeling indices did not correlate with survival in either the irradiated or the nonirradiated cohort, nor with overall survival in the series as a whole. CONCLUSION: Immunohistochemical assessment of p53 accumulation and Ki-67 expression does not help in predicting the survival of patients with supratentorial fibrillary astrocytomas or in predicting whether particular patients are likely to benefit from radiotherapy.

Interactive image-guided surgery of the spine--use of the ISG/Elekta Viewing Wand to aid intraoperative localization of a sacral osteoblastoma.

The intraoperative localization of small osteoid osteomas and osteoblastomas of the spine is often difficult. The authors report a patient with a small sacral osteoblastoma in whom the experimental use of an Interactive Image-Guidance Stereotactic system, to aid localization, is described. The Elekta Viewing Wand is a spatial localization device primarily designed for intracranial procedures. We evaluated its potential role in the localization and minimally invasive excision of a sacral osteoblastoma in this patient. A basic assessment of the limitations encountered in extracranial use of this system is presented and possible solutions to minimize these problems are discussed.

Intra-operative image guidance in otolaryngology--the use of the ISG viewing wand.

The ISG viewing wand is an intra-operative guidance system with a proprioceptive robotic-like jointed arm. It provides surgeons with almost instantaneously reconstructed computer-generated CT or MRI images in two or three dimensions and can correlate any point within the operative field to its corresponding locus on the reformatted scan images. In addition to having been used in over 400 neurosurgical patients in Bristol, 14 patients with skull-base, cerebello-pontine angle or temporal bone lesions have also undergone wand-guided resections. The wand has proved to be particularly useful in pre-operative planning, allowing minimally-invasive incisions, providing per-operative navigation, identifying the relationship and proximity of important anatomical structures and in assessing the extent of lesion resection. We illustrate the advantages of intra-operative image-guidance by discussing four cases. The potential applications of this form of imaging technology to other otolaryngological procedures are discussed.

The ISG viewing wand: an application to atlanto-axial cervical surgery using the Le Fort I maxillary osteotomy.

Surgical access to the clivus and upper cervical spine may be facilitated by a number of approaches. The Le Fort I maxillary osteotomy has been described to give improved access to the skull base for removal of tumours and treating vertebrobasilar aneurysms. We describe a case in which the combination of a particularly high translocation of the body of C2 and poor mouth opening had precluded a standard transoral approach by restricting access to the operative field. Anterior decompression of the body of C2 was therefore performed via a maxillary down-fracture with the aid of an interactive image guidance system, the ISG Viewing Wand. The ISG Viewing Wand is a new intra-operative 3 dimensional (3D) image guidance system which has now been used in over three hundred neurosurgical cases at Frenchay Hospital, Bristol. We briefly discuss the principles of the viewing wand and describe its unique application providing anatomical navigation in upper cervical spine surgery.

The impact of interactive image guided surgery: the Bristol experience with the ISG/Elekta viewing Wand.

From June 1992 to August 1994 we have accumulated a 305 case experience with the ISG Viewing Wand, the first commercially available system for interactive image guided neurosurgery. Prior to the arrival of the wand 2.5% of intracranial procedures were carried out using the Leksell G frame for image guidance. Since the arrival of the wand that percentage of procedures suitable for image guidance has increased to 10%. The wand was used for 287 supratentorial procedures, 108 craniotomies, 48 trephine exposures, 34 burr hole biopsies, 4 ventriculoscopies and 1 shunt insertion, 19 posterior fossa explorations were performed, 28 skull base procedures, including 22 transsphenoidal pituitary operations, 3 petrousectomies and 3 orbital explorations were also carried out. In addition 3 spinal cases were included in the series, 2 transoral explorations and 1 sacral laminectomy. The technique was applicable to 193 tumour cases, 14 vascular cases including 7 aneurysms and 16 epilepsy cases. Both CT (70%) and MRI (30%) scans were used for image guidance. Contour matching algorithms were used for registration throughout. Since the arrival of the wand conventional stereotaxy has been used for 26 cases, 22 stereotactic biopsies, 2 thalamotomies and 2 craniotomies (0.5% of intracranial procedures). We conclude that contour matching, interactive image guidance using a mechanical arm has replaced frame based stereotaxy in our department except for point source localisation in deep midline structures. It is a technique that has universal application to intracranial neurosurgical procedures and as such represents a major advance in image guided neurosurgery.

Advances in image-directed neurosurgery: preliminary experience with the ISG Viewing Wand compared with the Leksell G frame.

Because of the limited application of frame-based stereotaxy to general neurosurgical procedures, we have carried out a preliminary evaluation of the ISG Viewing Wand, a frameless image-directed surgical system that is based on the rapid reformat and accurate three-dimensional reconstruction capability of parallel processor-based computer technology. We have compared the first 36 cases carried out with the system in the Frenchay Neurosurgery Department with a retrospective analysis of the previous 36 cases carried out using the Leksell G frame. The stereotactic cases were completed over a period of 15 months, representing 2.8% of intracranial procedures. The wand cases were completed in 3 months, 13% of the intracranial practice during that time. The wand was used for 28 supratentorial craniotomies (76%), four infratentorial procedures (11%) and five biopsy procedures (13%). Conventional stereotaxy was not used for posterior fossa or skull base procedures. Supratentorial craniotomy was carried out in nine cases (25%), while the remaining 27 cases involved point source localization within the cranium (75%). The mean preparation time prior to surgery was 65 min for the stereotactic cases and 37 min for the wand cases. We therefore conclude that the indications for frame-based stereotaxy and Viewing Wand use are mutually exclusive. Leksell stereotaxy remains the method of choice for point source localization deep within the cranium. All other procedures requiring an image-directed minimally invasive surgical approach are more appropriately carried out using the Viewing Wand. The system has potential immediate application in supratentorial, skull base and infratentorial tumour surgery, vascular surgery, epilepsy surgery and upper cervical spine surgery.

The management of patients with an intrinsic supratentorial brain tumour.

The management of patients presenting with supratentorial glioma between 1978 and 1986 is reviewed. Complete follow-up in 517 cases was obtained. One hundred and fifty eight patients were not submitted to any form of surgery, 299 patients were biopsied and 60 patients underwent craniotomy and internal decompression. The no surgery group contained a higher proportion of patients with poor prognostic indicators than either the biopsy or craniotomy groups. The craniotomy group consisted of patients with better prognostic indicators than the biopsy group, in particular, younger age and more favourable site, type and grade of tumour. This was reflected in the difference in outcome between the groups. Median survival was 14 months in the craniotomy group, four months in the biopsy group and 2.2 months in the no surgery group. The outcome in patients with histologically proven malignant gliomas was best in those patients who received radiotherapy. The craniotomy group had a median survival of 18.5 months, a two year survival of 48% and a five year survival of 9%. The median survival following radiotherapy of those patients with proven malignant gliomas who had a biopsy was 9.5 months with a two year survival of 16% and a five year survival of 2%. These results compare favourably with studies which have adopted a more aggressive approach, suggesting that outcome is determined as much by patient selection using favourable prognostic indicators as by the treatment itself. The need for prospective trials of the management of unselected consecutive glioma patients randomizing them to conservative and radical treatment groups in order to define the role of both conventional therapy and radical therapy is discussed.

The role of needle biopsy in the management of malignant spinal compression.

With the changing management of malignant spinal cord compression there has been a reduction in numbers of patients treated by conventional laminectomy. This has resulted in a move either to the use of radiotherapy or to the use of more major surgical procedures such as the transthoracic approach. In both of these situations a more logical approach to deciding on the treatment modality to be used can be achieved by determining the histology of the lesion by percutaneous needle biopsy. This paper describes the technique of needle biopsy and presents evidence that shows that a reliable and immediate diagnosis can be achieved by the use of smear histology.