Percutaneous transforaminal endoscopic lumbar discectomy for sciatica

4 Efficacy

This section describes efficacy outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.

4.1 A systematic review of transforaminal endoscopic surgery for symptomatic lumbar disc herniation reported that the median percentage improvement (measured using a visual analogue scale for pain) in non‑controlled studies for leg pain was 88% (7 studies, n=1,558) and for back pain was 74% (5 studies, n=1,401). There was no significant difference in improvement between intradiscal and intracanal techniques (leg pain 83% versus 88%; back pain 75% versus 70%). A retrospective comparative study of 60 patients comparing transforaminal endoscopic lumbar discectomy (n=30) against interlaminar endoscopic lumbar discectomy (n=30) reported a decrease in mean visual analogue scale scores (ranging from 0 to 10, 0 indicating best and 10 worst scores) for leg and back pain at mean 2.2‑year follow‑up. For transforaminal discectomy, back pain reduced from 5.2 to 2.4 and leg pain reduced from 7.4 to 1.6, whereas for interlaminar discectomy, back pain reduced from 5.5 to 2.4 and leg pain reduced from 7.6 to 1.7 (no significant differences between the groups).

4.2 The systematic review reported that the median improvement in functional status (assessed using the Oswestry disability index questionnaire for low back pain‑specific functional disability) for non‑controlled studies was 83% (3 studies, n=624). The retrospective comparative study of 60 patients reported improvements in mean Oswestry disability index scores (ranging from 0 to 100, 0 indicating no disability and 100 maximum disability) from 52% to 12% in the transforaminal group and from 51% to 15% in the interlaminar group at mean 2.2‑year follow‑up (no significant difference between the groups).

4.3 The systematic review reported that the median percentage of patients in non‑controlled studies who returned to work was 90% (5 studies, n=757). The retrospective comparative study of 60 patients reported that the mean time to return to work was 4.9 weeks for the transforaminal group and 4.4 weeks for the interlaminar group (no significant difference between the groups).

4.4 The systematic review reported that the median score in global perceived effect for non‑controlled studies was satisfactory in 85% and poor in 6% of patients (15 studies, n=2,544). There was no significant difference in median scores between intradiscal and intracanal techniques (85% satisfactory [3 studies, n=279] versus 86% satisfactory [12 studies, n=2,292]) or between far lateral herniation (86% satisfactory; 2 studies, n=52); central herniation (91% satisfactory; 1 study, n=71) and all types of herniation (83% satisfactory; 9 studies, n=1,810). The controlled studies found no significant difference in median global perceived effect score between transforaminal endoscopic surgery and open lumbar microdiscectomy (84% versus 78% satisfactory; 5 studies, n=1,102). The sum of 'excellent' and 'good' scores was reported as 'satisfactory'.

4.5 The systematic review reported that the median percentage of patients in non‑controlled studies who were satisfied with treatment was 78% (3 studies, n=181).

4.6 A case series of 55 patients who had transforaminal endoscopic lumbar discectomy reported that there was significant improvement in many aspects of quality‑of‑life scores. These were SF‑36 scores for physical function, role physical, bodily pain, vitality, social function, role emotional and mental health (all p<0.05 except for general health scores at 6‑month and 2‑year follow‑up, which were 66.4 at baseline, 67.1 at 6 months and 68.5 at 2 years). These improvements correlated with improvements in the North American Spine Society score.

4.7 The comparative study of 60 patients reported incomplete removal of the disc fragments in 3% (1/30) of patients in the transforaminal group and in 7% (2/30) in the interlaminar group. Open surgery was needed in all these patients.

4.8 The systematic review reported that the median rate of recurrence in non‑controlled studies (13 studies, n=2,612) was 1.7% (range 0–12%). Recurrence was defined as reappearance of a symptomatic lumbar disc herniation at the same level within a month or after a pain‑free interval of more than a month. There was no significant difference in median recurrence rates between intradiscal (0.7%; 3 studies, n=217) and intracanal techniques (3.2%; 10 studies, n=2,395) or between far lateral herniation (2.6%; 2 studies, n=76) and all types of herniation (3.6%; 9 studies, n=2,201). The controlled studies found no significant difference in median recurrence rates between transforaminal endoscopic surgery (5.7%) and open lumbar microdiscectomy (2.9%; 4 studies, n=1,182).

4.9 The systematic review reported that the median reoperation rate in non‑controlled studies was 7% (range 0–27%; 28 studies, n=4,135). There was no significant difference in median reoperation rates between intradiscal (7.5%; 14 studies, n=1,267) and intracanal techniques (4.6%; 15 studies, n=3,098); or between far lateral herniation (8.0%; 5 studies, n=214); central herniation (4.6%; 1 study, n=71) and all types of herniation (5.6%; 15 studies, n=2,934). The controlled studies found no significant difference in median reoperation rates between transforaminal endoscopic surgery (6.8%) and open lumbar microdiscectomy (4.7%; 15 studies, n=2,934). The most common cause of reoperation was persistent symptoms because of missed lateral bony stenosis and remnant fragments.

4.10 The specialist advisers listed key efficacy outcomes as reduced back or leg pain, frequency of dysaesthetic pain, relief of sciatic pain, reduced blood loss, reduced incidence of spinal instability, shorter operating time, length of hospital stay, early return to work and patient satisfaction.