Modified transforaminal lumbar endoscopic discectomy for surgical management of extraforaminal lumbar disc herniation: case series and technical note.

Objective: Extraforaminal lumbar disc herniation (ELDH) represents a unique clinical entity, presenting particular challenges in surgical management. Transforaminal lumbar endoscopic discectomy (TLED) represents a minimally invasive, full-endoscopic procedure that is increasingly selected for surgical treatment of lumbar disc herniation, being theoretically ideal in patients with ELDH. Performance of TLED for management of ELDH has been reported in specific studies in the recent literature. However, foraminal anatomy is significantly disrupted in cases of ELDH, a fact that may represent a true challenge for the operating surgeon, in terms of proper endoscopic visualization. Hence, the aim of this study was to investigate midterm clinical outcomes of a unique modification of the TLED technique in patients with ELDH, in an attempt to enhance endoscopic visualization of foraminal structures and to facilitate safe and effective decompression in these cases.

Methods: Twenty-five patients with ELDH were enrolled in this study. All patients underwent modified TLED (mTLED) in the authors' center and were retrospectively assessed. Clinical evaluation was performed via the visual analog scale at 6 weeks; at 3, 6, and 12 months; and at 2 and 5 years postoperatively on an outpatient basis. Moreover, the functional status of enrolled individuals was evaluated with modified Macnab criteria at the end of follow-up.

Results: All patients underwent successful mTLED; the mean operative time was 23.7 ± 3.4 minutes. All patients were discharged on the same day as their operation, exhibiting no major perioperative complications. Three patients (12%) reported transient postoperative dysesthesia, which was completely resolved 6 weeks postoperatively. Recorded visual analog scale values were significantly ameliorated up to the end of follow-up, featuring maximal improvement at 6 weeks, with subsequent minimal amelioration and stabilization. According to modified Macnab criteria, excellent or good outcomes were observed in 23 patients (92%), whereas the outcome was fair in 2 patients (8%).

Conclusions: mTLED represents a feasible, safe, and effective alternative to conventional TLED and conventional open procedures for the management of ELDH. However, the precise role of this technical modification should be further investigated in future studies.