Restoration of the Spinous Process Following Muscle-Preserving Posterior Lumbar Decompression via Sagittal Splitting of the Spinous Process

BACKGROUND: In lumbar spinal stenosis, spinous process-splitting decompression has demonstrated good clinical outcomes with preservation of the posterior ligamentous complex and paraspinal muscles in comparison to conventional laminectomy, but the radiological consequence and clinical impact of the split spinous processes have not been fully understood. METHODS: Seventy-three patients who underwent spinous process-splitting decompression were included. The bone union rate and pattern were evaluated by computed tomography performed 6–18 months after surgery and compared among subgroups divided according to the number of levels decompressed and the extent of spinous process splitting. The bone union pattern was classified into three categories: complete union, partial union, and nonunion. The visual analog scale (VAS) score, Oswestry disability index (ODI), and walking distance assessed both before and 24–36 months after surgery were compared among subgroups divided according to the union pattern of the split spinous process. RESULTS: Overall, the rates of complete union, partial union, and nonunion were 51.7%, 43.2%, and 5.1%, respectively. In the subgroup with partial splitting of the spinous process, the rates were 85.7%, 14.3%, and 0%, respectively; those of the subgroup with total splitting of the spinous process were 32.9%, 59.2%, and 7.9%, respectively. With single-level decompression, a higher rate of union was observed compared with multilevel decompression. The VAS, ODI, and walking distance were significantly improved after surgery and did not differ according to the degree of union of the split spinous process. CONCLUSIONS: We found that the single-level operation and partial splitting of the spinous process were favourable factors for obtaining complete restoration of the posterior bony structure of the lumbar spine in spinous process-splitting decompression.

Prognostic Factors of Surgical Outcome after Spinous Process-Splitting Laminectomy for Lumbar Spinal Stenosis

STUDY DESIGN: A retrospective case review. PURPOSE: To assess the clinical and radiographic outcomes and identify the predictive factors associated with poor clinical outcomes after lumbar spinous process-splitting laminectomy (LSPSL) for lumbar spinal stenosis (LSS). OVERVIEW OF LITERATURE: LSPSL is an effective surgical treatment for LSS. Special care should be taken in patients with degenerative lumbar scoliosis (DLS). METHODS: A consecutive retrospective case review of patients undergoing LSPSL for LSS with a minimum 2-year follow-up was performed. Mild DLS and mild degenerative spondylolisthesis (DS) were included in the study. The Japanese Orthopedic Association (JOA) score and recovery rate were reviewed. Poor clinical outcome was defined as a recovery rate or =5 mm was found in 8 of 24 patients (33%) in the DS group. A progression of curvature > or =5degrees was found in 5 of 14 patients (36%) in the DLS group. The progression of scoliosis and slippage did not influence the clinical outcome. CONCLUSIONS: The clinical and radiographic outcomes of LSPSL for LSS were favorable. Pre-existing DLS was significantly associated with poor clinical outcome.

Spinous Process-Splitting Hemilaminoplasty for Intradural and Extradural Lesions

OBJECTIVE: To describe a novel spinous process-splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration. METHODS: The spinous process was split, the area of the facet lamina junction was drilled, and en bloc hemilaminectomy was then performed. After removing intradural and posterior epidural lesions, we fitted the previously en bloc-removed bone to the pre-surgery same shape, and held it in place with non-absorbable sutures. Surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014. Bony union of the reconstructed lamina was assessed using computed tomography (CT) at 6 months after surgery. RESULTS: Spinous process-slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient. Because we were able to visualize the margin of the ipsilateral and contralateral dura, we were able to secure space for removal of the lesion and closure of the dura. None of the cases showed spinal deformity or other complications. Bone fusion and maintenance of the spinal canal were found to be perfect on CT scans. CONCLUSION: The spinous process-splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura. Furthermore, we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored.

Comparison of Spinous Process-Splitting Laminectomy versus Conventional Laminectomy for Lumbar Spinal Stenosis

STUDY DESIGN: Seventy-five patients who had been treated for lumbar spinal stenosis (LSS) were reviewed retrospectively. PURPOSE: Invasion into the paravertebral muscle can cause major problems after laminectomy for LSS. To address these problems, we performed spinous process-splitting laminectomy. We present a comparative study of decompression of LSS using 2 approaches. OVERVIEW OF LITERATURE: There are no other study has investigated the lumbar spinal instability after spinous process-splitting laminectomy. METHODS: This study included 75 patients who underwent laminectomy for the treatment of LSS and who were observed through follow-ups for more than 2 years. Fifty-five patients underwent spinous process-splitting laminectomy (splitting group) and 20 patients underwent conventional laminectomy (conventional group). We evaluated the clinical and radiographic results of each surgical procedure. RESULTS: Japanese Orthopaedic Association score improved significantly in both groups two years postoperatively. The following values were all significantly lower, as shown with p-values, in the splitting group compared to the conventional group: average operating time (p=0.002), postoperative C-reactive protein level (p=0.006), the mean postoperative number of days until returning to normal body temperature (p=0.047), and the mean change in angulation 2 years postoperatively (p=0.007). The adjacent segment degeneration occurred in 6 patients (10.9%) in the splitting group and 11 patients (55.0%) in the conventional group. CONCLUSIONS: In this study, the spinous process-splitting laminectomy was shown to be less invasive and more stable for patients with LSS, compared to the conventional laminectomy.