Frameless stereotactic placement of foramen ovale electrodes in patients with drug-refractory temporal lobe epilepsy.

OBJECTIVE: Semi-invasive foramen ovale electrodes (FOEs) are used as an alternative to invasive recording techniques in the presurgical evaluation of patients with temporal lobe epilepsy. To maximize patient safety and interventional success, frameless stereotactic FOE placement by use of a variation of an upper jaw fixation device with an external fiducial frame, in combination with an aiming device and standard navigation software, was evaluated by the Innsbruck Epilepsy Surgery Program. METHODS: Patients were immobilized noninvasively with the Vogele-Bale-Hohner headholder (Medical Intelligence GmbH, Schwabmünchen, Germany) to plan computed tomography and surgery. Frameless stereotactic cannulation of the foramen and intracranial electrode placement were achieved with the help of an aiming device mounted to the base plate of the headholder. Ease of applicability, safety, and results obtained with foramen ovale recording were investigated. RESULTS: Twenty-six FOEs were placed in 13 patients under general anesthesia. The foramen ovale was successfully cannulated in all patients. One patient reported transient painful mastication after the procedure as a complication attributable to use of the Vogele-Bale-Hohner mouthpiece. In one patient, a persistent slight buccal hypesthesia was present 3 months after the procedure. To pass the foramen, slight adjustments in the needle position had to be made in 10 sides (38.4%). To place the intracranial electrodes, adjustments were necessary six times (23.7%). An entirely new path had to be planned once (3.8%). Seizure recording provided conclusive information in all patients (100%). Outcome in operated patients was Engel Class Ia in six patients, Class IId in one patient, Class IIb in one patient, and Class IVa in one patient (minimum follow-up, 6 mo). CONCLUSION: The Vogele-Bale-Hohner headholder combined with an external registration frame eliminates the need for invasive head clamp fixation. FOE placement can be planned "offline" and performed under general anesthesia later. This can be valuable in patients with distorted anatomy and/or small foramina or in patients not able to undergo the procedure under sedation. Results are satisfactory with regard to patient safety, patient comfort, predictability, and reproducibility. FOEs supported further treatment decisions in all patients.

Accuracy of stereotactic electrode placement in deep brain stimulation by intraoperative computed tomography.

The purpose of this study was to evaluate the accuracy of stereotactic electrode placement in patients undergoing deep brain stimulation by using pre- and postoperative computed tomography (CT). Twenty-three patients with movement disorders (Parkinson's disease (n=7), tremor (n=9), dystonia (n=7)) treated with bilateral deep brain stimulation (DBS) (overall 46 target points) were investigated. The target point of the electrode was planned stereotactically in combination with a preoperative stereotactic helical computed tomography (CT). A postoperative CT, which was carried out still in the operating room while the patient had the stereotactic frame on the head, was performed in order to control the position of the electrodes in relation to the previously planned target point. The position of the four electrode contacts was measured according to the Talairach space (AC-PC line) and compared with the coordinates of the planned target point. The mean spatial distance of planned target perpendicular to the electrode was 1.32+/-0.75mm. These results show the high accuracy of stereotactic implantation of DBS electrodes assisted by pre- and postoperative image fusion with computed tomography (CT).

Long-term outcome of laminectomy for spinal stenosis in octogenarians.

STUDY DESIGN: Cohort study with follow-up after at least 1.5 years. OBJECTIVES: The purpose of this study was to determine long-term safety and efficacy of laminectomy in octogenarians. SUMMARY OF BACKGROUND DATA: This is the first study evaluating the outcome in octogenarians with well-defined lumbar spinal stenosis. This study was designed to provide some guidance in clinical-practical decisions in the treatment of aged patients with lumbar stenosis. METHODS: We evaluated long-term outcome after laminectomy in 23 consecutive patients affected by lumbar spinal stenosis. Comorbidity was assessed using the Cumulative Illness Rating Scale for Geriatrics. At follow-up, all patients completed a questionnaire containing the Visual Analog Pain Scale and the Oswestry Disability Index. The use of analgesics was assessed from chart review of their family physician. RESULTS: The average age at the time of surgery was 82.2 +/- 2.6 years; the mean follow-up was 2.7 +/- 1.2 years. The mean of the Cumulative Illness Rating Scale for Geriatrics total score was 7.7 +/- 4.3, reflecting the normative comorbidity-values of octogenarians. At follow-up, 4 patients had died. The Oswestry Disability Index for the remaining patients was 36.4 +/- 28%. The daily nonsteroidal anti-inflammatory medication had decreased from 1.9 to 0.1 equivalent analgesic doses and the amount of morphine from 0.6 to 0.2 equivalent narcotic doses. The Pain Score on the Visual Analog Pain Scale decreased from 85 to 39. After surgery no patient had claudication. CONCLUSION: On the long-term, decompressive laminectomy in selected octogenarians results in decreased disability, decline of analgesics usage, and increased quality of life.