Tag: Annulus fibrosus

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

J Neurosurg Spine 42:572–578, 2025

The study investigates buttock pain in patients with lumbar disc herniation (LDH), identifying it as a common, independent symptom. It found that buttock pain is associated with contained herniation and an intact annulus fibrosus, and can be effectively treated with endoscopic discectomy.

• Buttock pain is common in patients with lumbar disc herniation (LDH), particularly in the L3–S1 segments, and is often independent of back and leg pain.

• The study examined 321 patients with single-level LDH who underwent endoscopic discectomy, finding that 75.4% experienced buttock pain.

• Buttock pain is more prevalent in patients with contained LDH and an intact annulus fibrosus.

• Endoscopic discectomy is effective in treating buttock pain, with significant improvements observed shortly after surgery and at the 1-year follow-up.

• The occurrence of buttock pain is not associated with age, sex, or specific spinal levels, indicating it as an independent symptom.

• The study suggests that altered intradiscal pressure may be a pathogenic factor for buttock pain in contained LDH.

• Residual buttock pain was more likely in L3–4 LDH, though the sample size for this segment was limited.

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Three-year results from a randomized trial of lumbar discectomy with annulus fibrosus occlusion in patients at high risk for reherniation

Acta Neurochirurgica (2019) 161:1389–1396

A larger defect in the annulus fibrosus following lumbar discectomy is a well-known risk factor for reherniation. Procedures intended to prevent reherniation by sealing or occluding the annular defect warrant study in high-risk patients. This study sought to determine 3-year results of lumbar discectomy with a bone-anchored annular closure device (ACD) or lumbar discectomy only (controls) in patients at high risk for reherniation.

Methods This multicenter randomized trial enrolled patients with sciatica due to lumbar intervertebral disc herniation who failed conservative treatment. Patients with large annular defects after lumbar limited microdiscectomy were intraoperatively randomly assigned to receive ACD or control. Clinical and imaging follow-up was performed at routine intervals over 3 years. Main outcomes included rate of reherniations, reoperations, and endplate changes; leg and back pain scores on a visual analogue scale; Oswestry Disability Index (ODI); Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-36; and adverse events adjudicated by a data safety monitoring board.

Results Among 554 randomized patients, the modified intent-to-treat population consisted of 272 patients in which ACD implantation was attempted and 278 receiving control; device implantation was not attempted in 4 patients assigned to ACD. Outcomes at 3 years favored ACD for symptomatic reherniation (14.8% vs. 29.5%; P < 0.001), reoperation (11.0% vs. 19.3%; P = 0.007), leg pain (21 vs. 30; P < 0.01), back pain (23 vs. 30; P = 0.01), ODI (18 vs. 23; P = 0.02), PCS (47 vs. 44; P < 0.01), and MCS (52 vs. 49; P < 0.01). The frequency of all-cause serious adverse events was comparable between groups (42.3% vs. 44.5%; P = 0.61).

Conclusions The addition of a bone-anchored ACD in patients with large annular defects following lumbar discectomy reduces the risk of reherniation and reoperation, and has a similar safety profile over 3-year follow-up compared with lumbar limited discectomy only.

 

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The Role of Hypoxia in Angiogenesis and Extracellular Matrix Regulation of Intervertebral Disc Cells During Inflammatory Reactions

Neurosurgery 81:867–875, 2017

The intervertebral disc (IVD) is an avascular structure, and is therefore stable under hypoxic conditions. Previous studies have demonstrated that hypoxia might be related to symptomatic degenerative disc diseases (DDDs); however, the pathomechanism is still poorly understood.

OBJECTIVE: To identify the effect of hypoxia on the production of inflammatory mediators, angiogenic factors, and extracellularmatrix-regulating enzymes of IVD cells during inflammatory reactions.

METHODS: Human nucleus pulposus (NP) and annulus fibrosus (AF) cells harvested during surgery for DDDs were cultured in macrophage conditioned media or interleukin (IL)-1β-stimulated media under hypoxic (2%) and normoxic (21%) conditions. Hypoxiainducible factor-1α transcription factor activation was analyzed by western blotting. IL-6, IL-8, vascular endothelial growth factor (VEGF), vascular cell adhesion molecule (VCAM), matrix metalloproteinase (MMP)-1,MMP-3, tissue inhibitor ofmetalloprotease (TIMP)-1, and TIMP-2 in conditioned media weremeasured by an enzyme-linked immunosorbent assay.

RESULTS: NP cells expressed higher hypoxia-inducible factor-1α in the IL-1β-stimulated group under hypoxic condition. MMP-1 was significantly increased in the AF cells under hypoxic condition; TIMP-1 and TIMP-2 were significantly decreased in both naïve NP and AF cells during hypoxia. Both cells in macrophage conditioned media significantly diminished the production of IL-6 and VCAM, while VEGF significantly increased during hypoxia. After 1 ng/mL IL-1β stimulation, IL-8, VEGF, MMP-1, and MMP-3 were significantly increased in both cell types during hypoxia, while VCAM, TIMP-1, and TIMP-2 were decreased.

CONCLUSION: We found that hypoxia can enhance the angiogenic ability of IVD during inflammatory reactions, and cause progress in development of DDD via extracellular matrix regulation in this in vitro study.

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