下腰椎爆裂性骨折的损伤特点和手术治疗选择

目的：探讨自行设计的下腰椎爆裂性骨折的评分系统用于指导手术方式选择的可行性。方法：回顾性分析2006年1月至2011年12月采用手术治疗，且资料完整的56例下腰椎单椎体爆裂性骨折病例，男42例，女14例；年龄19～65岁，平均43．1岁。高处坠落伤40例，交通伤12例，重物砸伤4例。损伤部位：L337例，L4 16例，L53例。按AO分型：A3．1型17例，A3．2型14例，A3.3型25例。脊髓神经功能按Frankel分级：B级2例，C级5例，D级9例，E级40例。按A0分型、后柱是否损伤及椎管占位程度进行综合评分，根据评分，分别选择跨伤椎固定、经伤椎置钉固定、联合后前入路和Ⅰ期后入路手术方式。对比术前、术后即刻和末次随访时Cobb角、伤椎前缘高度恢复及椎管占位情况的变化，观察植骨融合情况以及内固定是否存在弯曲、松动或断裂现象。采用Frankel分级标准评定脊髓神经恢复情况，末次随访时对患者的局部疼痛和工作状态进行评定。结果：56例切口无感染，未出现脊髓神经症状加重现象。均获得随访，随访时间12-60个月，平均28．5个月，随访期间未出现内固定松动或断裂现象。在Cobb角、椎体前缘高度及椎管占位恢复方面，术后即刻与术前相比，差异有统计学意义（P〈0．05），术后即刻与末次随访时相比，差异无统计学意义（P〉0．05）。植骨融合情况：跨伤椎固定方式融合13例，经伤椎固定方式融合20例，联合后前入路和Ⅰ期后入路方式20例均获得植骨融合。脊髓神经功能有1-2级的恢复，C级1例，D级3例，E级52例。患者局部疼痛评定：Pl52例，P23例，P31例。工作状态分级：W112例，W239例，W35例。结论：由于下腰椎与胸腰段在解剖、生物力学方面的差异，其具有完全不同的损伤特点。而根据AO分型、后柱是否损伤及椎管占位程度进行的综合评分，是指导下腰椎爆裂性骨折手术治疗选择的较好方法，下腰椎爆裂性骨折应根据损伤程度而采用不同的手术方法。

Injury characteristics and surgical treatment of lower lumbar vertebral burst fractures

Objective： To investigate the feasibility of utilizing self-designed score system for lower lumbar vertebral burst fractures to select surgical approach. Methods：From January 2006 to December 2011 ,the clinical data of 56 patients with lower lumbar vertebra burst fractures who underwent surgical treatment were retrospectively analyzed. There were 42 males and 14 females with an average age of 43.1 years old （ranged, 19 to 65）. Causes of injury included falling down （40 cases）, traffic accidents （12 cases）, and crashing injury by heavy objects （4 cases）. Injury site was L3 in 37 cases, L4 in 16 cases, and L5 in 3 cases. According to the AO classification, 17 cases were type A3.1,14 cases were type A3.2,25 cases were type A3.3. Accord- ing to Frankel grade of nerous function, 2 cases were grade B, 5 cases were grade C, 9 cases were grade D and 40 cases were grade E. Surgical methods and approaches were chosen based on the comprehensive evaluation of AO classification, condition of posterior column injury and spinal canal encroachment. Surgical methods and approaches included traMs-vertebra fixation （ 15 cases）, intra-vertebra pedicle screw fixation （21 cases ）, combination of anterior and posterior approaches （ 11 cases）, one- stage posterior approaches （9 cases）. Cobb angles, restorations of the affected vertebral anterior border height, and conditions of spinal canal encroachment were compared before and after surgery. Conditions of bone graft fusion and internal fixation （if bending,loosening or breakage existed） were observed. Spinal cord functions were assessed according to Frankel grade. Local- ized pain and working status of patients were also assessed at the last follow-up. Results： No incision infection was found and no spinal nerve symptoms improved in all of 56 patients. All patients were followed up for 12 to 60 months with a mean of 28.5 months, without internal fixation loosening or breakage. There was significant differences in Cobb angle, vertebral anterior bor- der height and recovery of spinal canal encroachment between preoperative and postoperative instantly （P〈0.05）, however, there was no significant difference between postoperative instantly and final follow-up （P〉0.05）. Thirteen cases obtained fusion by traMs-vertebra fixation, 20 cases obtained fusion by intra-vertebra fixation, and 20 cases were treated by the combination ofanterior and posterior approaches or one-stage posterior approaches all of patients obtained fusion. Spinal nervous function re- covered Ⅰ to Ⅱ grade, 1 case was grade C ,3 cases were grade D ,52 cases were grade E. Localized pain was assessed as P1 in 52 cases,P2 in 3 cases,and P3 in 1 case. Working status was classified into W1 in 12 cases,W2 in 39 cases,and W3 in 5 cas- es. Conclusion：The lower lumbar vertebra and thoracolumhar junction exhibit different injury characteristics due to variations in anatomy and biomechanics. A comprehensive score of the AO classification,posterior column injury and degree of spinal canal encroachment will guide the selection of surgical method and approach for the treatment of lower lumbar vertebra burst fractures.