Five-year outcomes and predictive factors of transforaminal full-endoscopic lumbar discectomy

Abstract

Although several studies have reported the effectiveness of transforaminal full-endoscopic lumbar discectomy (TELD), no cohort study on the long-term outcomes of TELD has been conducted. Thus, this study aimed to evaluate the long-term clinical outcomes of TELD and to determine the factors predicting favorable outcome.Five-year longitudinal data of 204 consecutive patients who underwent TELD were collected. Outcomes were assessed using the visual analog scale (VAS) pain score, Oswestry disability index (ODI), patient satisfaction rating, and the modified Macnab criteria.The mean VAS score for leg pain improved from 7.64 at the baseline to 1.71, 0.81, 0.90, and 0.99 at postoperative 6 weeks, 1 year, 2 years, and 5 years, respectively (P <.001). The mean ODI improved from 67.2% at the baseline to 15.7%, 8.5%, 9.4%, and 10.1% at postoperative 6 weeks, 1 year, 2 years, and 5 years, respectively (P <.001). The overall patient satisfaction rate was 94.1%. Based on the modified Macnab criteria, 83.8% of patients had excellent or good results. In this study, younger patients with intracanal disc herniation tended to have better outcomes than elderly patients with foraminal/far-lateral disc herniation (P <.05).Transforaminal endoscopic lumbar discectomy offers favorable long-term outcomes with minimal tissue damage. Postoperative pain and functional status may change over time. Proper patient selection remains essential for the success of this minimally invasive procedure.

Figure 1

Schematic drawing and intraoperative views of the surgical technique. A. The basic principle of transforaminal approach is that the landing point should be as close to the target as possible and that the exiting nerve root should not be irritated. B. A large disc fragment is removed through a working sheath. C. At the final step, the anatomical details are well demonstrated including the decompressed NR, the PLL, and the maternal disc (D). NR = nerve root, PLL = posterior longitudinal ligament.

Figure 2

Illustrated case of a 44-year-old male patient with an excellent postoperative outcome. A. Preoperative MRI showing extruded disc herniation at the right L4-5 level. B. Postoperative MRI showing complete epidural decompression after selective removal of the herniated disc. MRI = magnetic resonance images.

Figure 3

VAS preoperatively and at 6-weeks, 6-months, 1-year, 2-years, and 5-years postoperatively. A. VAS for radicular leg pain. B. VAS for back pain. VAS = visual analogue scale.

Figure 4

ODI preoperatively and at 6-weeks, 6-months, 1-year, 2-years, and 5-years postoperatively. ODI = Oswestry disability index.

Figure 5

Global outcome based on the modified Macnab criteria: excellent in 61 (29.9%), good in 110 (53.9%), fair in 27 (13.5%), and poor in 6 (2.9%) patients.

Figure 6

Survival curve for reoperations. Nine patients (4.4%) underwent subsequent open surgery for incomplete decompression or recurrent disc herniation. Seven reoperations were performed within 1 year; the remaining 2 reoperations were performed after 4 years.

Figure 7

Schematic comparison of transforaminal approach according to the zone of disc herniation. A. For intracanal disc herniation, standard transforaminal approach can be performed avoiding the exiting nerve root and DRG. B. For foraminal or far-lateral disc herniation, steeper transforaminal approach is required and it may cause DRG irritation or postoperative dysesthesia. DRG = dorsal root ganglion.