OBJECTIVE: The purpose of this report is to investigate the efficacy of unilateral laminotomy on both ipsilateral and contralateral decompression and compares outcome of both sides using this unilateral approach.
METHODS: Unilateral laminotomy under microscopic visualization was performed to achieve bilateral decompression. Thirty‐nine consecutive patients who underwent this procedure were analyzed prospectively using ODI, VAS pain score to evaluate symptoms in both legs, and the radiological morphometric index to calculate the anterior‐posterior diameter and mid‐canal width using CT myelography or MRI.
RESULTS: The mean follow‐up time was 16.2 months. The mean ODI was 48.4 preoperatively and 14.2 postoperatively. The mean dural sac widening of the ipsilateral side (3.1mm, 87.0%) was significantly larger (p < 0.01) than that of the the contralateral side (2.0mm, 45.6%). The VAS improvement ratio [(Preoperative VAS score ?Postoperative VAS score)/(Preoperative VAS score) × 100)] for the pain in each leg was 75.4%, (ipsilateral side) and 73.7% (contralateral side). While the VAS improvement ratio for pain in each side was significantly reduced, the difference in the VAS ratio between sides was statistically insignificant (p= 0.64). There were two cases of dural tearing, one case of transient paresthesia of nerve roots bilaterally, and two cases of transient paresthesia of the contralateral nerve root. One case of iatrogenic instability (2.6%) was observed during the follow‐up period.
CONCLUSION: This technique allows for significant decompression of the contralateral canal and excellent clinical outcomes. Sparing of the ligament complex and the contralateral paraspinal musculature results in decreased surgical time, and decreased risk of post‐operative iatrogenic instability. The incidence of perioperative complications was less than previous reports of bilateral laminotomy or laminectomy procedures.