Buttock pain in lumbar disc herniation: clinical characteristics, risk factors, and surgical outcomes.

Objective: Buttock pain is a common symptom in patients with lumbar degenerative disorders. While the nature of buttock pain remains unclear, clinicians consider it as either nociceptive back pain or radicular leg pain. Some have proposed that buttock pain may be a mixed symptom of radicular pain and referred pain, although buttock pain in spine practice is less studied. This study aimed to determine the occurrence rate, clinical characteristics, risk factors, and surgical outcomes of buttock pain in patients with lumbar disc herniation (LDH).

Methods: A prospective study was performed on patients with single-level LDH who underwent endoscopic discectomy at the authors' hospital between 2020 and 2023. Back pain, buttock pain (the region between the iliac crest and buttock crease), and leg pain were measured using the numeric rating scale (NRS) before and after surgery. On MRI, degenerative findings, including disc degeneration, Modic changes, and endplate defects, were assessed. The location of the hernia was recorded, and disc herniation was classified as contained or uncontained. The presence or absence of annulus rupture was further examined with endoscopy. The associations of buttock pain with MRI and endoscopic findings, back pain, and leg pain were examined.

Results: During the defined period, a study was conducted on 321 patients with single-level LDH. Buttock pain presented in 242 (75.4%) patients. Buttock pain was a common symptom for L3-4, L4-5, and L5-S1 LDH. Buttock pain was more common in patients with contained LDH than in those with uncontained LDH (85.8% vs 69.7%, p = 0.001). Furthermore, buttock pain was more common in LDH patients with an intact annulus compared with those patients with a ruptured annulus (86.7% vs 68.7%, p < 0.001), as assessed using endoscopy. Compared with baseline, buttock pain quickly improved on the 2nd day after surgery (NRS score 5.44 ± 2.07 vs 0.84 ± 1.27, p < 0.001). At the 1-year follow-up, buttock pain had resolved in 91.2% of cases and improved in the remaining 8.8% of patients, although they still had some residual buttock pain.

Conclusions: Buttock pain is a common symptom in patients with L3-S1 LDH. Buttock pain is not related to back pain and radiating leg pain and thus should be considered as an independent symptom in LDH. Similar to radiating leg pain, buttock pain can be effectively treated with endoscopic discectomy.