Burr hole microsurgical subtemporal selective amygdalohippocampectomy

Methods. The study included a consecutive series of 43 adult patients with drug-resistant TLE, involving 24 women and 19 men (1.8/1). Surgeries were performed at the Burdenko Neurosurgery Center from 2016 to 2019. To perform subtem- poral SAH through the burr hole with the diameter of 14 mm, we used two types of approaches: preauricular, 25 cases, and supra-auricular, 18 cases. The follow-up ranged from 36 to 78 months (median 59 months). One patient died 16 months after surgery (accident).

Neuropsychology. In 26 patients (19 dominant side; PAA, 11; SAA, 8), neu- ropsychological studies were performed both immediately before surgery and 6–12 months after surgery. This group did not include patients who had a significant decrease in memory before surgery and patients with poor knowledge of the Russian language.

The Rey Auditory Verbal Learning Test (RAVLT) adopted to Russian speakers was used to assess verbal mem- ory. Visual memory was assessed using the Brief Visuos- patial Memory Test-Revised (BVMT-R), and the Judgment of Line Orientation (JLO) was used to assess visuospatial skills. Motor memory was evaluated by the test of assimila- tion and reproduction of a series of 3 movements. Execu- tive functions were assessed by a set of methods: frontal assessment battery (FAB), letter-number sequence (L-N Sequence), and digit symbol substitution test (DSST).

Psychiatry. Psychiatric examination was performed before and after (immediately and after 6–12 months) surgery in 41 patients. A special structured psychiatric interview was used to iden- tify depression, anxiety, emotional lability, irritability, family relationship difficulties, hyperesthesia, and neurotic sleep disturbance. Psychiatric disorders were detected in 21 (51.2%) patients, most often in the form of depression, 12 (29.3%), and anxiety, 10 (24.4%).

Results. By the third year after surgery, Engel I outcome was achieved in 80.9% (34 cases) of cases and Engel II in 4 (9.5%) and Engel III and Engel IV in 4 (9.6%) cases. Among the patients with Engel I outcomes, anticonvulsant therapy was com- pleted in 15 (44.1%), and doses were reduced in 17 (50%) cases. Verbal and delayed verbal memory decreased after surgery in 38.5% and 46.1%, respectively. Verbal memory was mainly affected by preauricular approach in comparison with supra- auricular (p = 0.041). In 15 (51.7%) cases, minimal visual field defects were detected in the upper quadrant. At the same time, visual field defects did not extend into the lower quadrant and inside the 20° of the upper affected quadrant in any case.

Burr hole microsurgical subtemporal SAH is an effective surgical procedure for drug-resistant TLE. It involves minimal risks of loss of visual field within the 20° of the upper quadrant. Supra-auricular approach, compared to preauricular, results in a reduction in the incidence of upper quadrant hemianopia and is associated with a lower risk of verbal memory impairment.