Radiological analysis of symptomatic complications after bilateral laminotomy for lumbar spinal stenosis

Synovial facet joint cysts after lumbar posterior decompression surgery

OBJECTIVE

Numerous studies have reported on synovial facet joint cysts of the spine as a primary lesion. The exact pathogenesis of those cysts is still controversial, but degeneration and destabilization seem to be underlying mechanisms. However, only a few reports have thus far investigated synovial cysts of the spine as postoperative complications of decompression surgery. In this retrospective clinical study, the authors focused on synovial cysts of the lumbar facet joints as complications after lumbar decompression surgery, with the aim of elucidating their pathophysiology.

METHODS

A total of 326 patients with 384 segments treated with posterior decompression surgery without fusion were included in the study. Of these segments, 107 were surgically decompressed unilaterally and 277 were decompressed bilaterally. After surgery, 18 of the 384 segments developed a complication of symptomatic facet synovial cyst. The anatomical and morphological evaluations of these segments were performed using functional plain radiographs, CT scans, and MR images.

RESULTS

All of the 18 segments with postoperative lumbar facet synovial cyst were treated with bilateral lumbar posterior decompression. There was no significant radiological lumbar spinal instability in any segments, although 17 of 18 segments demonstrated facet articular spondylotic changes. Moreover, 12 of 18 patients demonstrated lumbar retrolisthesis in the neutral position.

CONCLUSIONS

Based on the authors' results, they propose that patients with lumbar degenerative disease who have a potential biomechanical lumbar instability such as disruption of the facet articular surface and hydrarthrosis or lumbar facet tropism might have a high risk for formation of lumbar facet synovial cyst after bilateral posterior decompression surgery.

Spontaneous spinal epidural hematoma management with minimally invasive surgery through tubular retractors: A case report and review of the literature

To report a minimally invasive paraspinal approach in the treatment of a case of spontaneous spinal epidural hematoma (SSEH). We additionally aim to review the relevant literature to enhance our knowledge of this disease. SSEH is an uncommon but potentially catastrophic disease. Currently, most appropriate management is emergence decompression laminectomy and hematoma evacuation. An 81-year-old woman was admitted to the neurology department with a chief complaint of bilateral numbness and weakness of the lower limbs and difficulty walking for 4 days with progressive weakness developed over the following 3 days accompanied with pain in the lower limbs and lower back. No history of trauma was reported. Magnetic resonance imaging of the thoracolumbar spine demonstrated an epidural hematoma extending from T-12 to L-5 with thecal sac and cauda equina displacement anterior. The patient was treated in our department with a minimally invasive approach. This operation method had been approved by Chinese Independent Ethics Committee. Three months following the operation, the patient had regained the ability to walk with the aid of a cane and myodynamia tests revealed normal results for the left lower limb and a 4/5 grade for the right limb. Importantly, no complications were exhibited from the surgical operation. The minimally invasive paraspinal approach through tubular retractors is demonstrated here as an effective alternative method for the treatment of SSEH.

Analysis of factors contributing to postoperative spinal instability after lumbar decompression for spinal stenosis

Objective

Decompressive laminectomy is one of the most commonly used surgical methods for the treatment of spinal stenosis. We retrospectively examined the risk factors that induce spinal instability, including slippage (spondylolisthesis) and/or segmental angulation after decompressive laminectomy on the lumbar spine.

Methods

From January 1, 2006 to June 30, 2010, 94 consecutive patients underwent first-time single level decompressive laminectomy without fusion and discectomy. Of these 94 patients, 42 with a follow-up period of at least 2 years were selected. We measured the segmental angulation and slippage in flexion and extension dynamic lumbar radiographs. We analyzed the following contributing factors to spinal instability: age/sex, smoking history, disc space narrowing, body mass index (kg/m²), facet joint tropism, effect of the lordotic angle on lumbar spine, asymmetrical paraspinal muscle volume, and surgical method and level.

Results

Female patients, normal lordotic angle, and asymmetrical paraspinal muscle volume were factors more significantly associated with spondylolisthesis (p-value=0.026, 0.015, <0.01). Statistical results indicated that patients with facet tropism were more likely to have segmental angulation (p-value=0.046). Facet tropism and asymmetry of paraspinal muscle volume were predisposing factors to spinal instability (p-value=0.012, <0.01).

Conclusion

Facet joint tropism and asymmetry of paraspinal muscle volume are the most important factors associated with spinal instability; therefore, careful follow-up after decompressive laminectomy in affected patients is necessary.