Objective: To compare clinical outcomes of microsurgical bilateral decompression via unilateral approach (MBDU) between trans longissimus and iliocostalis approach, a novel lateral paraspinal approach(LPA), and classic Wiltseapproach for single level degenerative lumbar stenosis. Methods: LPA approach was researched by imaging measurement and cadaver anatomy. Retrospective analysis of a total 124 cases(male/female 75/49, aged(55±14) years) received single-level MBDU due to degenerative lumbar stenosis from 2016 to 2018 in Beijing Tiantan Hospital. Patients were categorized into two groups according to spinal canal morphology. Group A: trefoil shape (n=48), received MBDU via LPA; Group B: round & oval shape (n=76), received MBDU via Wiltse approach. Clinical parameters, including visual analogue scale (VAS) of pain, OswestryDability Index (ODI), satisfaction rate were assessed before the operation and at the latest follow-up. The internal fixation and intervertebral fusion were evaluated by X-ray and CT.The data were compared with single sample t test between the two groups. Results: The feasibility of trans longissimus and iliocostalis approach was proved by imaging measurement and anatomic study. The tube’s maximum tilt angle in LPA group was 65°, and it was 40°in Wiltse group. There was no significantly difference in the operating time, bleeding and drainage volume between the two groups((120±27) min vs (115±32) min, (104±31) ml vs (110±41) ml, (50±15) ml vs (47±18) ml, respectively, t=1.246,-1.917,1.730,all P>0.05). In both groups, VAS and ODI scores significantly improved at the latest follow-up when compared with those before the operation (all P<0.05), but those were all comparable between the two groups(all P>0.05). The excellent rate of subjective satisfaction for the clinical efficacy in group A and B was 89.6%(43/48) and 86.8%(66/76) respectively (χ(2)=0.208,P>0.05). Conclusions: LPA approachfor microsurgical bilateral decompression via unilateral approach (MBDU) in degenerative lumbar stenosis is safe and effective, it has advantages in direct vison of contralateral nerve root canal decompression for trefoil shaped spinal canal.

目的： 比较最长肌与髂肋肌间隙入路（LPA）与Wiltse肌间隙入路显微镜下单侧入路双侧减压（MBDU）对腰椎管狭窄症的疗效。 方法： 通过影像学测量及形态学解剖证明最长肌与髂肋肌间隙入路的可行性。回顾性分析2016年至2018年北京天坛医院骨科收治的共124例[男75例/女49例，年龄（55±14）岁]因退变性腰椎管狭窄症接受单节段MBDU病例。根据椎管形态分为A组LPA入路48例，B组Wiltse肌间隙入路76例。记录各组手术时间、出血量、引流量、术后并发症。术前及末次随访时入路侧、对侧下肢疼痛及腰痛视觉模拟评分（VAS），Oswestry功能障碍指数（ODI），术后患者主观满意度。术后通过X线、CT评估内固定及椎间融合情况。组间数据比较采用独立样本t检验。 结果： 最长肌与髂肋肌间隙稳定存在，套筒置放最大倾斜角度LPA入路为65°，Wiltse入路为40°。所有患者获得平均20个月的随访。A组手术时间（120±27） min、出血量（104±31) ml、引流量（50±15) ml，B组则分别为（115±32） min、(110±41) ml、(47±18) ml，两组差异均无统计学意义（t=1.246、-1.917、1.730，均P>0.05）。术中硬膜撕裂各1例和3例；术后脑脊液漏各2例和3例。两组末次随访时入路侧、对侧下肢疼痛、腰痛VAS、ODI评分均较术前显著改善，组内差异均有统计学意义（均P<0.05），而组间差异无统计学意义（均P>0.05）。A组患者主观满意度优良率为89.6%（43/48），B组为86.8%（66/76），组间差异无统计学意义（χ(2)=0.208，P>0.05）。 结论： 经LPA行MBDU治疗退变性腰椎管狭窄症安全有效，对于三叶草形椎管的对侧神经根管减压有优势。.