Subcortical language and non-language mapping in awake brain surgery: the use of multimodal tests

Subcortical language and non-language mapping in awake brain surgery- the use of multimodal tests

Acta Neurochir (2015) 157:577–588

Awake craniotomy is currently considered the gold standard to maximise the extent of resection and to minimise postoperative deficits in patients with supratentorial tumours near eloquent areas. In addition to direct electrical stimulation (DES) of the cortex, intraoperative subcortical mapping is increasingly used as it optimises the benefit-to-risk ratio by decreasing (permanent) postoperative neurological deficits. However, only little attention has been paid to subcortical mapping procedures and especially the tasks to be used.

Methods In this article, language and non-language testing at the subcortical level is described and discussed by means of three right-handed cases with a glioma in the left hemisphere. To assess subcortical functions, a multimodal test named the Quick Mixed Test was developed (QMT). Pre-, intra- and postoperative test results are described and discussed in detail.

Results Based on the analysis of these preliminary observations, a number of clinical recommendations for intraoperative subcortical mapping may be made: (1) the selection of a set of language and non-language tests needs to be tailored according to the functional corticosubcortical regions affected by the tumoral lesion and the patient’s characteristics (job/hobby/daily life activities); (2) language and non-language tests should be presented in a multimodal and alternating way during subcortical stimulation since this approach enables screening various functions simultaneously or in a very short period of time and (3) spontaneous speech is a useful adjunct to standardised tests since it most resembles daily life conversation.

Conclusion Administration of multimodal tests during subcortical DES such as the experimental QMT may facilitate identification of eloquent pathways leading to avoidance of permanent neurological impairments.

Unsuccessful Percutaneous Endoscopic Lumbar Discectomy: A Single-Center Experience of 10 228 Cases

Unsuccessful Percutaneous Endoscopic Lumbar Discectomy- A Single-Center Experience of 10 228 Cases

Neurosurgery 76:372–381, 2015

Percutaneous endoscopic lumbar discectomy (PELD) has remarkably evolved with successful results. Although PELD has gained popularity for the treatment of herniated disc (HD), the risk of surgical failure may be a major obstacle to performing PELD. We analyzed unsuccessful cases requiring reoperation.

OBJECTIVE: To find common causes of surgical failure and elucidate the limitations of the conventional PELD technique.

METHODS: A retrospective review was performed on all patients who had undergone PELD between January 2001 and December 2012. Unsuccessful PELD was defined as a case requiring reoperation within 6 weeks after primary surgery. Chart review was done, and preoperative, intraoperative, and postoperative radiographic reviews were performed. All unsuccessful PELD cases were classified according to the type of HD, location of herniation, extruded disc migration, working channel position, and intraoperative and postoperative findings.

RESULTS: In 12 years, 10 228 patients had undergone PELD; 436 (4.3%) cases were unsuccessful. The causes were incomplete removal of HDs in 283 patients (2.8%), recurrence in 78 (0.8%), persistent pain even after complete HD removal in 41 (0.4%), and approach-related pain in 21 (0.2%). Incomplete removal of the HD was caused by inappropriate positioning (95 cases; 33.6%) of the working channel and occurred in central HDs (91 cases; 32.2%), migrated HDs (70 cases; 24.7%), and axillary type HDs (63 cases; 22.3%).

CONCLUSION: Proper surgical indications and good working channel position are important for successful PELD. PELD techniques should be specifically designed to remove the disc fragments in various types of HD.