Stereotactic management of intrinsic brain stem lesions

Between 1981 and 1991, seventy-two cases of brain stem lesions have undergone CT or MRI-directed stereotactic surgery using the Brown-Roberts-Wells or Cosman-Roberts-Wells stereotactic systems. In 16 cases, the pre-operative diagnosis of haematoma had been made and the procedure was for therapeutic aspiration. In fifty-six cases, the pre-operative diagnosis was uncertain although intrinsic tumour was suspected. Histological diagnosis was obtained in fifty-four of these and unexpected findings of haematomas, granulomas, leucoencephalopathy, demyelinating disease, vasculitis and radiation necrosis occurred in over 15% of the cases. There were no operative deaths and morbidity was low. Advances in neuroradiological imaging with CT and MRI have increased the detection rate of brain stem lesions and image-directed stereotactic biopsy makes it possible in most cases to obtain histological diagnosis with relatively low morbidity which is important for treatment and prognosis. MRI-directed biopsies can compliment CT-guided biopsies in most cases where the lesion is not adequately delineated on the CT image.

Proliferating cell nuclear antigen (PCNA): expression in samples of human astrocytic gliomas

In this retrospective study, 55 astrocytic tumours were stained with monoclonal antibody PC10 which recognizes the proliferating cell nuclear antigen (PCNA) in formalin fixed, paraffin-wax embedded sections. All the cases were graded using the Daumas-Duport system and the PCNA labelling indices (LIs) were correlated with tumour grades. Mean PCNA LI was 4.1% in the grade II, 8.1% in the grade III and 26.1% in the grade IV group. Six juvenile and cerebellar (grade I) astrocytomas had a mean PCNA LI of 5.6%. In general PCNA LI increased with tumour grade, but there was considerable variation of LIs especially in grade IV tumours which often had very high PCNA LIs (up to 72.7%). PC10 may be a useful complementary technique in surgical neuropathology, but the significance of the high LIs, seen in a proportion of glioblastomas, needs to be further determined.

Open stereotactic amygdalohippocampectomy--clinical, psychometric, and MRI follow-up

The clinical results of six cases of open stereotactic amygdalohippocampectomy for medically intractable epilepsy are presented. Outcome in terms of seizure control (highly satisfactory in five patients) and neuropsychological sequelae (all cases had poor functioning of the contralateral temporal lobe pre-operatively) are detailed. In addition the use of post-operative Magnetic Resonance Imaging (MRI) is demonstrated and shown to be a valuable tool in providing the crucially accurate baseline that is required for more meaningful follow-up outcome studies.

Infant botulism: a review in South Australia (1980-89)

Between March 1980 and March 1989 there were six identified cases of infant botulism. The presenting symptoms were predominantly poor feeding, lethargy and constipation, and the presenting signs were predominantly hypotonia, weak gag reflex and respiratory difficulty. All required intensive care and prolonged hospital stays. Recovery was eventually complete in all cases. Infant botulism is an uncommon condition but early recognition with adequate intensive care usually results in complete recovery.

Event-related potential measures of attention in moderately depressed subjects

Prior research has inferred attentional changes related to depression from evidence concerning other cognitive processes. The present experiment investigated attentional changes related to depression in a more direct manner. Subjects were 32 young adults attending college. Depression was measured by self-report measures. In an auditory selective attention task similar to that of Hansen and Hillyard (1980), auditory event-related potentials (ERPs) were recorded from central (Cz) and frontal (Fz) scalp locations. Evidence for selective attention was manifest as the difference wave (Nd), which showed larger mean and peak amplitudes for the less difficult of two attention conditions. Nd was also shown to have an earlier peak latency at the Cz scalp location. However, there was no significant difference between the Depressed and Control groups as measured by the Nd wave. Significant differences were found between groups for the amplitude of the N1 peak of the ERP at the Fz scalp location. This suggests that the Depressed group differed in arousal level or sensory sensitivity from the Control group.

Stereotactic insertion of intracerebral electrodes in the investigation of epilepsy

Intracerebral electroencephalography is sometimes necessary in the pre-surgical evaluation of patients with drug-resistant epilepsy, in order to define the site(s) of seizure onset. Accurate depth electrode insertion would ideally require multimodal image integration, repetitive and non-invasive localization, assessment of positional accuracy and freedom in target and entry point selection. A method for the acquisition of the multimodal image stereotactic information, necessary for the precise targeting of the mesial temporal structures, and the operative technique used for the accurate placement of the intracerebral electrodes is described. The use of the Gill-Thomas (G-T) stereotactic repeat localizer offers the degree of temporal freedom during the data acquisition period of the electrode implantation procedure which leads to the advantage of an unhurried multi-image integration and targeting in any individual case combined with less discomfort for the patient. The integration of the G-T repeat localizing system with the existing components of the Cosman-Roberts-Wells (CRW-3) stereotactic system offers additional advantages. The target-centered arc-radius design allows complete freedom in the selection of the entry point, offers the possibility of multiple trajectories through the same entry point and permits a choice of either oblique or orthogonal lateral approaches, that are particularly useful for the electroencephalographic sampling of the posterior mesial temporal structures. The satisfactory localizing value of the technique and the additional advantage of easy confirmation of the positional accuracy of the electrodes during the postoperative period, using standard radiographic and magnetic resonance imaging studies, increases the potential of the technique for precise placement of depth electrodes during the pre-surgical evaluation of patients with epilepsy.

Accuracy in frame-based and frameless stereotaxy

Stereotactic surgery is currently undergoing great changes with a large number of frameless methodologies being developed alongside traditional frame-based systems. As a result, there is considerable uncertainty over the future clinical roles of the numerous stereotactic options now offered. We have reviewed the current scientific issues regarding accuracy in both frame-based and frameless stereotaxy. Frame-based systems have the advantage of proven clinical utility and instrument carriage with a high degree of mechanical stability and accuracy. Frameless methods are more complex, but also more flexible, and may have wide applications in general neurosurgery if clinical efficacy is confirmed.

Brachial plexus injury: deafferentation pain and dorsal root entry zone (DREZ) coagulation

The nature of deafferentation pain in cases of brachial plexus injury is described. The natural course of the symptoms together with conservative treatment is outlined. The theoretical background of the dorsal root entry zone (DREZ) coagulation, and its clinical indications, operative techniques and results are presented.

Volumetric analysis of epilepsy surgery resections using high resolution magnetic imaging: technical report

A method is described for accurately measuring the volume and site of epilepsy surgery resections utilizing magnetic resonance imaging. Accuracy has been assessed using post-mortem studies, and both the intra- and interobserver variability is consistently less than 5%. The technique has so far been applied to 25 patients following a variety of operations for medically intractable epilepsy. It provides the crucially accurate baseline required for meaningful follow-up outcome studies of epilepsy surgery. Consequently, it should allow the development of more precise prognostic indices for such operations.

Multimodal imaging integration and stereotactic intracerebral electrode insertion in the investigation of drug resistant epilepsy

Insertion of intracerebral electrodes for EEG recording is sometimes necessary during the pre-operative evaluation of patients with drug resistant epilepsy to define the site of seizure onsets. The precise and accurate placement of the electrodes requires a stereotactic technique of insertion based on correlated information derived from computerised imaging and stereotactic angiography. Described methods of multimodal stereotactic image integration present limitations in terms of satisfactory relocation and ability to spread data acquisition over a period of time. An alternative method of stereotactic acquisition of multimodal image information using the Gill-Thomas stereotactic repeat localiser is presented. Digital Angiographic (DSA), Computerised (CT) and Magnetic Resonance Imaging (MRI) data were correlated and used for target selection. The positional accuracy of the electrodes was confirmed repeatedly during the recording period with standard radiographic and MRI means and found to be satisfactory. There were no permanent complications in any of the patients included in the study. Stereoangiography correlative to computerised neuro-imaging offered a high degree of safety during the operation. Non-invasive relocation was an important feature of the combined system which was particularly helpful and duly appreciated by the patients. The temporal freedom provided during the investigative and operative period offers the advantage of an unhurried multi-image integration and targeting combined with less discomfort for the patient. The positional accuracy of the electrodes was easily verified during the post-operative period and this information added to the electroence-phalographic localising value of the technique.

The role of image-directed biopsy in the diagnosis and management of brainstem lesions

The appreciation that brainstem tumours do not comprise a homogeneous pathological group and that up to 20% of the preoperative radiological diagnoses of brainstem lesions prove at operation to be wrong, has established the need for a firm histological diagnosis prior to treatment. Current neuro-imaging modalities may have increased the diagnostic accuracy and the detection rate of intrinsic brainstem lesions, but open exploration in cases without an exophytic component is still associated with a low diagnostic yield and considerable morbidity. A series of 72 brainstem lesions approached stereotactically with CT or MRI guidance is presented. A transcortical frontal precoronal trajectory was used in 58 and a suboccipital transcerebellar route in 14. Haematoma was diagnosed preoperatively in 16 cases and therapeutic aspiration was planned. In 56 cases the diagnosis was uncertain, although intrinsic tumour was suspected. A histological diagnosis was established in 52 cases, although in the remaining four cases a tumour was excluded. Unexpected findings occurred in over 15% of the cases. There were no operative deaths and the morbidity was low. In no case was there a permanent neurological deterioration directly related to the procedure, although there was a transient deterioration in two patients and another patient required early re-aspiration of a haematoma.

Anorectal function in patients with complete supraconal spinal cord lesions

Anorectal manometry and sphincter electromyography were performed in 23 patients with complete supraconal traumatic spinal injuries and 30 age and sex matched control subjects. Basal pressures in the spinal group were similar to those in normal subjects but conscious control of sphincter activity was abolished in all spinal patients. Discriminant rectal sensation was also abolished during rectal distension, but 40% of patients experienced a dull pelvic ache at maximum levels of distension. Phasic rectal contraction and anal relaxation were present but exaggerated and induced at lower distending volumes than in normal subjects. The configuration of the rectal pressure/volume relationship was linear in patients compared with a reversed 'S' shape in normal subjects. The external anal sphincter response to rectal distension was noticeably attenuated, reinforcing the view that this spinal reflex is heavily modulated by supraspinal centres under normal circumstances. The external anal sphincter response to increases in abdominal pressure was also attenuated, and the anal pressures were strongly correlated with the level of the lesion and the abdominal pressure the patient could generate. No spinal patient showed a decrease in external anal sphincter activity during straining 'as if to defecate.' The exaggerated anorectal smooth muscle responses to rectal distension and the attenuated external sphincter response explain why patients with complete supraconal spinal lesions experience uncontrollable reflex defecation, while the persistance of external and sphincter contraction and the absence of any external anal sphincter relaxation during straining 'as if to defecate' might explain the difficulty that these patients have in consciously expelling rectal contents.

Early experience with the Gill Thomas Locator for computed tomography-directed stereotactic biopsy of intracranial lesions

The Gill Thomas Locator is a stereotactic adaptor for the Brown-Roberts-Wells and Cosman-Roberts-Wells systems. It is a noninvasive device that relies on temporary fixation to the maxillary teeth. A series of 20 patients have had stereotactic biopsies with this system. A diagnostic biopsy was obtained in 19 cases. The frame was well tolerated, accurately relocatable, and allowed computed tomographic scanning and surgery to be conducted at different times.

Outcome of paediatric bacterial meningitis 1979-1989

OBJECTIVE

To determine the outcome of all cases of paediatric bacterial meningitis over the 11-year period 1979-1989 and discuss the role of adjunctive therapy with dexamethasone.

DESIGN AND SETTING

The study was performed by retrospective case review at Flinders Medical Centre, a general teaching hospital.

RESULTS

There were 80 episodes in 79 patients. The age range was 2 days to 15 years (mean, 1.7 years). Haemophilus influenzae type b was the commonest organism (60 of 80 cases; 75%). There were five deaths (6.3%). Sensorineural hearing loss was found in six of 71 children (8.5%) and was bilateral and severe in four (5.6%). Other problems included learning difficulties (12.7%), motor problems (7%), speech delay (7%), hyperactivity (4.2%), blindness (2.8%), obstructive hydrocephalus (2.8%) and recurrent seizures (2.8%).

CONCLUSIONS

Bacterial meningitis remains a disease with significant morbidity and mortality. Adjunctive therapy with dexamethasone should be considered, and vaccination against Haemophilus influenzae type b should be routine.

Image directed stereotactic surgery for brain stem lesions

Advances in neurological imaging may have increased the diagnostic accuracy and the detection rate of intrinsic brain stem lesions, but a histological diagnosis is still an essential requirement for rational and appropriate management. Open exploration allows biopsy and resection in cases where an exophytic component is present. The surgical inaccessibility and the resultant morbidity of these approaches, however, associated with a low diagnostic yield in cases with no visible surface abnormality, are important limiting factors. A series of 45 brain stem lesions stereotactically approached with CT or MRI guidance is presented. A transcortical frontal pre-coronal trajectory was used in all of them. Haematoma was preoperatively diagnosed in 10 cases and the procedure was for therapeutic aspiration. Of 35 cases where the diagnosis was uncertain, although intrinsic tumour was suspected, positive results were obtained in 33, while unexpected findings of granuloma, lymphoma, angioma, leucoencephalopathy, vasculitis and radiation necrosis were found in over 10% of the cases. There were no operative deaths and the morbidity was low. In no case was there a permanent neurological deterioration directly related to the procedure, although there was a transient deterioration in two patients and one patient required early reaspiration of a haematoma. Image directed stereotactic approaches to brain stem lesions can combine a high degree of accuracy (offering positive histological diagnoses) with a low operative morbidity. MRI directed biopsies can complement CT guided ones thus increasing the number of suitable cases and improving the success rate. The frontal precoronal transcortical trajectory provides safe access to the majority of the brain stem targets.

Open stereotactic selective amygdalo-hippocampectomy for drug resistant epilepsy

Selective removal of the medio-basal temporal structures has been introduced as an alternative to standard temporal lobectomy in the treatment of intractable temporal lobe epilepsy not related to gross structural lesions. Various approaches have been described for the surgical excision of the amygdalo-hippocampal complex, each of them presenting advantages and limitations. The recently introduced computer-assisted technique of volumetric stereotactic excision of deep-seated intracerebral lesions combines precision of targeting with elimination of unnecessary cortical trauma and may potentially provide an alternative method in the treatment of temporal lobe epilepsy. We present our experience of stereotactic volumetric selective amygdalo-hippocampectomy in six patients with medically intractable temporal lobe epilepsy. The criteria for selection, the pre-operative evaluation and the operative technique are discussed. All patients had a cessation or considerable reduction in seizure frequency while the morbidity was minimal.

Improved and extended exact and asymptotic methods for the combination of 2 x 2 tables

Exact and approximate methods for analyzing the common odds ratio in the combination of 2 x 2 tables are programmed. The approximate methods are improved by incorporating bias and skewness corrections in testing and estimation. Exact methods are done more efficiently by employing network theory. This makes more feasible the exact analyses of sparse data, large numbers of 2 x 2 tables each based on small numbers. Additional tests of interaction, particularly for sparse data, are added. Another feature is the point and interval estimation of the attributable risk. The various aspects of the program are illustrated in three numerical examples. An executable version of this program, for IBM compatible PCs, requires about 314K for up to 500 tables. It is available from the authors upon submission of a PC diskette formatted with MS-DOS.

Neurogenic bladder dysfunction in lumbar intervertebral disc prolapse

Lumbar disc prolapse with urinary dysfunction is an uncommon condition. The clinical, pathological and follow-up details of 30 patients are presented. Detrusor recovery is rare and most patients are left with an areflexic bladder. Female patients with lumbar disc prolapse and an areflexic detrusor who strain to empty their bladders are likely to develop genuine stress incontinence. This may be managed by the early institution of intermittent self-catheterisation, which may reduce the need for incontinence surgery.

Stereotactic brachytherapy for malignant glioma using a relocatable frame

Interstitial brachytherapy for recurrent gliomas normally necessitates the invasive application of a stereotactic frame by screw-fixation which must be kept on for several hours. The use of a relocatable stereotactic frame offers many advantages over conventional systems. We present our experience in 18 patients and verify that the frame used is accurate, comfortable, well tolerated and associated with no major disadvantages.

Does combined epidural lignocaine and fentanyl provide better anaesthesia for ESWL than lignocaine alone?

The efficacy of epidural fentanyl combined with lignocaine 1.5% with adrenaline 1:200,000 was studied in a randomised, double-blind, controlled trial of two hundred patients undergoing extracorporeal shock wave lithotripsy with or without ancillary procedures. The quality of anaesthesia was assessed using linear analogue pain scores, the patient's impression, and the rate of intra-operative intervention by the anaesthetist. Postoperative symptomatology was also recorded. The only significant difference lay postoperatively in that the fentanyl-ancillary procedure sub-group had less pain approximately one hour postoperatively (P = 0.01). In the context of this study and in the presence of an adequate autonomic and somatic local anaesthetic blockade, the addition of epidural fentanyl does not appear to confer any significant advantage other than to enhance postoperative analgesia.

Delivery of vitamin A from parenteral nutrition solutions in neonates

The delivery of Vitamin A from parenteral nutrition may be suboptimal. To investigate this sample solutions were prepared and Vitamins A and E concentrations from the solution bags and the efflux from the lines were measured over a 24 h period. The results show that mean Vitamin A levels in the solution bags declined from a range of 57-66% to 17% of expected over 24 h and at the efflux of the lines from a range of 13-29% to 4% of expected, giving a calculated delivery of 10% of expected. There is no improvement with light protection or an ethylene vinyl acetate system. Mixing the vitamin preparation in lipid showed less decline (from 92 to 70% of expected over 24 h), but the delivery was variable. When vitamins were added to a lipid-dextrose-amino acid solution, there was minimal loss from the solution bag and line with a calculated delivery of 94% of expected. The delivery of Vitamin E from all systems was constant with a mean calculated delivery of 74% of expected. It was concluded that the mixing of multivitamins in dextrose-amino acid-electrolyte solutions results in poor delivery of Vitamin A and this is improved by mixing lipid solution. This is important in preterm infants who are prone to become Vitamin A deficient.