Low Back Pain Induced by Posterior Longitudinal Ligament Incision in Percutaneous Transforaminal Endoscopic Lumbar Discectomy.

OBJECTIVE To illustrate the posterior longitudinal ligament is one of the tissue candidates who can contribute to low back pain (LBP). METHODS This is a retrospective study. A series of 72 patients who underwent single-level percutaneous endoscopic lumbar discectomy performed for lumbar disc herniation with LBP from June 2014 to June 2016 were examined. There are 42 males and 30 females. The ages of patients were 40 to 57 years, and the mean age was 49.8 years. The symptomatic disc level was at L4-5 in 43 patients and L5 S1 in 29 patients. Thirty-two patients (19 patients in L4-5 disc level, 13 patients in L5 S1 disc level) had LBP (which was limited to the lower back and buttock area) before the operation. All of the operative approaches were performed under local anesthesia. A posterior body diagram (15 cm × 10 cm) was made for this study to record the pain distribution. The centered foci of low back pain were subjectively recorded before, during, and after the operation. The transforaminal endoscopic spine system technology was used in this study. Radiological examinations (X-ray, computed tomography, and magnetic resonance imaging) were performed prior to and after surgery. The Visual Analogue Score (VAS) and Oswestry Disability Index (ODI) scores were taken before and after the surgery to observe the degree of pain. The VSA and ODI score before and after operation were expressed as mean ± SD, and compared by t-test for statistical analysis. RESULTS When inciting the posterior longitudinal ligament during the operation, all 72 patients had provoked low back pain. Forty-three patients with symptomatic discs at L4-5 had pain foci in the lower back and upper gluteal region under the L4 spinous process. Twenty-nine patients with symptomatic discs at L5 S1 had pain foci in the gluteal region under the S1 spinous process. The pain localizations of L4-5 and L5 S1 were different. After the surgery, the provoked low back pain disappeared, and had not returned in any of the patients at the 6-month follow-up. After the operation, one patient suffered from lower limb pain that he did not have before the operation, and the lower limb pain abated a few days later. Three patients had cerebrospinal fluid leakage and were treated with higher pressure applied on the incision and bed rest for 10 days. During the 6-months follow-up period, the mean VAS decreased from 5.97 ± 1.10 to 2.13 ± 0.78. The mean ODI score decreased from 23.14 ± 3.28 to 7.92 ± 1.85. CONCLUSIONS The intervertebral posterior longitudinal ligament may be one of the tissues from which low back pain originates.