体重指数对微创手术治疗单节段腰椎管狭窄症并腰椎不稳疗效的影响

The effect of body mass index on the outcome of minimally invasive surgery for lumbar spinal stenosis complicated with lumbar instability

目的：探讨体重指数（BMI）对微创减压经椎间孔腰椎间融合术联合经皮椎弓根螺钉内固定术治疗单节段腰椎管狭窄症并腰椎不稳的疗效的影响。方法：对2010年3月-2011年3月57例微创通道下行减压经椎间孔腰椎椎间融合术联合经皮椎弓根螺钉内固定手术治疗的单节段腰椎管狭窄症并腰椎不稳患者进行回顾性分析，按患者BMI不同分为3组，A组：正常体重组（BMI〈25kg／m^2），男14例，女17例；B组：超重组（25kg/m^2≤BMI〈30kg／m^2），男7例，女12例；C组：肥胖组（BMI≥30kg/m^2），男3例，女4例。记录每组患者手术时间、术中出血量、术后住院时间、手术并发症情况；术前、术后6个月及末次随访时行JOA评分（29分法）、Oswestry功能障碍指数（ODI）评定：末次随访时根据Bridwell椎间融合标准评价各组融合情况。年龄、性别构成比、术前JOA评分与ODI及随访时间3组之间无统计学差异（P〉0．05），比较3组疗效。结果：3组患者手术时间有统计学差异（P〈0．05），术中出血量及术后住院时间无统计学差异（P〉0．05）。A组及C组各有1例术中硬膜囊撕裂；B组1例骨质疏松患者行椎间融合时融合器打入上位椎体中，术中取出融合器，予椎体间自体骨植骨融合；术后4例（A组1例，B组1例，C组2例）患者出现切口愈合不良，经抗生素及换药等治疗术后15—18d切口愈合。随访8-20个月，3组患者术后6个月及末次随访时JOA评分及ODI均较术前明显改善（P〈0．05），术后6个月及末次随访时JOA评分及ODI3组之间均无统计学差异（P〉0．05）；末次随访时，根据JOA评分计算临床改善率并评估手术疗效，其中A组优25例，良5例，可1例；B组优12例，良7例；C组优4例，良3例；3组优良率无统计学差异（P〉0．05）。末次随访时，A、B及C组融合率分别为93．5％、94．7％和100％，3组之间无统计学差异（P〉0．05）：无融合器沉降、移位或塌陷，无螺钉断裂及松动。结论：微创减压经椎间孔腰椎椎间融合术联合经皮椎弓根螺钉内固定手术是治疗单节段腰椎管狭窄症并腰椎不稳的一种较好手术方法，BMI对其疗效无明显影响。

Objectives： To investigate the effect of body mass index on the outcome of minimally invasive decompression and transforaminal lumbar interbody fusion with percutaneous pedicle screw internal fixation for lumbar spinal stenosis complicated with lumbar instability. Methods： A retrospective study was carried on 57 cases with single segment lumbar spinal stenosis complicated with lumbar instability undergoing bilateral decompression via unilateral approach and transforaminal lumbar interbody fusion through an expandable tubular retractor and percutaneous pedicle screw internal fixation from March 2010 to March 2011. All patients were divided into three groups according to BMI. Group A： normal weight（BMI〈25kg/m2）, 14 males and 17 females; Group B： overweight （25kg/m2≤BMI〈30kg/m2）, 7 males and 12 females; Group C： obese（BMI≥30kg/m2）, 3 males and 4 females. The operation time, intraoperative blood loss, postoperative hospital stay and complications were recorded. Low back pain was assessed by JOA scores（29） and Oswestry disability index（ODI） at pre- and post-operation（six months and final follow-up）. The fusion rates were evaluated based on the Bridwell criterion at final follow-up. There was no statistical difference in age, sex, JOA scores, ODI before surgery, follow-up period among three groups（P〉0.05）. The clinical efficacy was compared among three groups. Results： There was significant difference with respect to operation time（P〈0.05）; while no statistical difference for blood loss or postoperative hospital stay among three groups （P〉0.05）. Leakage of cerebrospinal fluid was noted in 1 case respectively in group A and C. 1 case in group B used autogenous bone graft without cage because of osteoporosis. Delayed healing of the skin incision were found in 4 cases and all healed after antibiotic treatment and dressing change 15-18 days after surgery. All patients were followed up for 8-20 months. JOA scores and ODI scale showed statistically significant improvements （P〈0.05）, and there was no statistical difference in JOA scores and ODI among three groups at six months after surgery and final follow- up（P〉0.05）. Based on the JOA improvement rate, there were 25 excellent, 5 good and 1 fair in group A, 12 excellent and 7 good in group B, 4 excellent and 3 good in group C. Three groups got similar clinical efficacy at final follow-up. The fusion rates in group A, B, C was 93.5%, 94.7% and 100% respectively（P〉0.05）, and there were no cages or pedicle screws related complications. Conclusions： Minimally invasive decompression and transforaminal lumbar interbody fusion with percutaneous pedicle screw internal fixation is reliable for single segment lumbar spinal stenosis complicated with lumbar instability. Patients with different BMI have the same clinical outcome.