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.

Experience in 300 cases of CT-directed stereotactic surgery for lesion biopsy and aspiration of haematoma.

Despite advances in imaging of the brain, an accurate diagnosis of brain lesions requires tissue sampling and histological verification. A series of CT-directed procedures has been performed in 300 patients with deep sited, multiple, diffuse, extensive, small or inflammatory lesions, brain stem haematomas and tumours presenting with epilepsy. A positive diagnosis was obtained in 271 cases (92.8%), no diagnosis in 21 cases (7.2%). Therapeutic results were also obtained in eight cases (2.7%) of brain stem haematoma aspiration. Complications occurred in 14 cases (4.7%) including one death (0.3%). Because of the importance of an accurate diagnosis in order to avoid inappropriate therapy, together with the relative safety of the technique, CT-directed stereotactic biopsy should be considered in all patients harbouring deep seated, multiple, diffuse, small or inflammatory brain lesions.