[Efficacy and safety of intraoperative electrical stimulation mapping for resection of WHO grade ii and iii gliomas within eloquent areas]. / Eficacia y seguridad del mapeo por estimulación eléctrica intraoperatoria para la extirpación de gliomas OMS grado ii y iii en áreas cerebrales elocuentes.

BACKGROUND AND OBJECTIVE: Despite the growing use of intraoperative electrical stimulation (IES) mapping for the resection of WHO grade ii and iii gliomas (GGII and GGIII) in eloquent areas, few studies have compared 2 series with and without IES. The present study compares 2 series of patients operated with and without IES at the same institution, analyzing the extent of resection, neurological morbidity, epilepsy prognosis and quality of life. PATIENTS AND METHODS: The surgical results in 2 series of patients with GGII and GGIII within eloquent were compared. Period A (2004-2009): 17 patients operated without IES. Period B (2009-2010): 19 patients operated with IES. RESULTS: The extent of tumor resection was 54.7% in group A and 79.9% in group B (P=.006). Six months after surgery, neurological morbidity was present in 8 patients of group A and one patient of group B (P=.015; odds ratio [OR] 16, 95% confidence interval [95% CI] 1.7-148.3). Two patients of group A with refractory epilepsy, and 8 patients of group B improved epilepsy control (P=.05; OR 42, 95% CI 2.1-825.7). Nine patients of group A and 18 patients of group B returned to the same socio-professional situation as before surgery (P=.015; OR 16, 95% CI 1.7-148.4). CONCLUSIONS: The comparison of IES mapping surgery to conventional surgery revealed that the former enables to: increase in 25.2% the extent of tumor resection, decrease in 48.1% the risk of permanent sequelae, improve epilepsy control and preserve quality of life.

Complications of endoscopic microdiscectomy using the EASYGO! system: is there any difference with conventional discectomy during the learning-curve period?

BACKGROUND: Microendoscopic discectomy (MED) is emerging as a minimally invasive alternative to conventional microsurgical discectomy (MSD). EASYGO! is a new system for spinal endoscopy that claims smooth transition from MSD to MED, with a reduced learning curve period. The aims of this study were to describe the complications that appeared during the learning curve period of MED and to compare their incidence with the rate and type of complications that occurred during a simultaneous non-randomised series of standard MSDs. METHODS: Between July 2009 and December 2010, 138 patients underwent scheduled first-time discectomy in our institution, 37 using an MED approach and 101 by a conventional MSD. A MED learning curve was obtained by plotting every case with its respective operative time. Complications, length of hospital stay, need of further surgery and outcome were prospectively recorded in both groups. RESULTS: The mean operative time was 66 min for the MSD group and 100 min for the MED group, although for the last 14 cases of the latter group the time was reduced. Curve-fitting techniques showed that the inverse equation, ƒ(x) = 122.12/x + 73.05, had the best correlation between case number and operative time. The learning curve was overcome after the 30th case. Complications occurred in 9.8 % of the MSD group and 8.1 % of the MED group (P = 0.49). Average length of hospital stay was 2.36 days for the MED group and 3.36 days for the MSD group (P = 0.01). The procedure successfully relieved patient symptoms in 68.63 % of the MSD group and 89.92 % of the MED group. No revision surgery was required in the MED group, but it was necessary in ten patients of the MSD group. CONCLUSIONS: Between 25 and 30 cases are needed to reach the learning curve's asymptote of MED. Even during this initial learning period MED is a safe procedure, with comparable results to those obtained with conventional MSD and with a similar complication rate. The key points for reducing intraoperative complications are an adequate expertise in MSD, a precise selection of initial cases, a proper surgical planning and a careful technique, which are mandatory to avoid unnecessary neurological injury in an otherwise secure surgical approach.