The technical note and approach related complications of modified lateral lumbar interbody fusion.

The aim of this study was to demonstrate the techniques of modified lateral lumbar interbody fusion and investigate its approach related complications. Fifty-two patients underwent with modified lateral lumbar interbody fusion (LLIF) in our center were studied retrospectively. There were 20 males and 32 females, aged from 45 to 82 years old (averaged at 66.0 ± 11.2). The diagnosis was as following: degenerative spinal scoliosis in 21 cases, lumbar spinal stenosis in 15, lumbar spinal spondylolisthesis in 12, spinal infection and spinal trauma in 2 respectively. The main techniques of modified LLIF included operation under direct visualization, improved transpsoas approach and novel designed retractor. The mean follow-up time was 9.2 ± 2.1 months (ranged from 6 to 12 months). Oswestry disability index (ODI) was used to assess the clinical outcome. The approach related complications of anterior thigh pain/numbness, hip flexion weakness and knee extension weakness were recorded. A total of 118 levels were performed with modified LLIF, one level in 17 cases, 2 levels in 10, 3 levels in 19 and 4 levels in 6 cases. The mean surgical time was 56.5 ± 13.1 min for 1 level, 94.5 ± 31.3 for 2 levels, 130.1 ± 41.5 for 3 levels and 208.3 ± 22.7 for 4 levels. The estimated blood loss during surgery was less than 10 ml every level. Preoperative ODI was 61.8% ± 20.1%, it was 22.5% ± 18.3% (t = 7.572, P = 0.000) at the last follow-up. The incidence rate of approach related complications was 11.5% (6/52), including anterior thigh pain 9.6% (5/52), numbness 7.7% (4/52) and hip flexion weakness 5.8% (3/52). No knee extension weakness, vascular injury, sympathetic nerve injury, visceral injury and ureteral injury was found in these series. Only one case had residual numbness in anterior thigh at the last follow-up. The incidence rate of complications increased significantly in patients underwent three or more levels interbody fusion compared to patients underwent one or two levels interbody fusion (X2 = 5.163, P = 0.023). The modified lateral lumbar interbody fusion may reduce the approach related complications of traditional lateral lumbar interbody fusion through the operation under the direct visualization, the improved transpsoas approach and the novel designed retractor.