ABSTRACT
Objective To investigate the short-term clinical outcome of one-level degenerative diseases for a single surgeon during his initial phase of performing a minimally invasive surgery oblique lumbar interbody fusion (OLIF) on the basis of perioperative parameters and follow-up data.Methods A prospective analysis of 49 consecutive patients that underwent a OLIF between November 2014 and March 2016 by corresponding author was performed.Only those patients that were single level,index surgeries were included.Every patient had a diagnosis of degenerative lumbar diseases including lumbar spondylolisthesis (25 cases),discogenic low back pain (14 cases) or segmental instability (10 cases).Patients underwent an indirect decompression and fusion using an expandable tubular retractor and single intervertebral cage with bilateral percutaneous pedicle screw fixation.49 patients were divided into the A group (the first 24 patients) and the B group (25 patients after the initial 24 patients).The following data were compared between the two groups:surgical time for Skin-Skin (minutes),estimated blood loss (ml),radiograph exposure time (seconds),the clinical and radiographic results,and intra-/postoperative complications.All intraoperative parameters only included the measurement and findings related with the OLIF procedure.The short-term clinical outcome of single level degenerative lumbar diseases treated by OLIF was assessed on the basis of follow-up data.The learning curve was measured using a logarithmic curve-fit regression analysis.Results Average operative time was significantly longer in the A group 47.1±10.6 min compared with the B group 37.2± 10.0 min.In comparison with the B group,the A group had significantly more X-ray exposure time (25.3±6.1 s versus 17.1±6.9 s).The operative and X-ray exposure time gradually decreased as the series progressed,and an asymptote was reached after about 20 cases.There was no statistically significant difference in intraoperative blood loss between the A group (28.1± 18.2) ml and the B group 24.4± 10.9 ml.The most observed complication was donor site pain (11 cases,45.8％),followed by thigh numbness/pain (5 cases,20.8％) and psoas/quadriceps weakness (2cases,8.3％),paralytic ileus (one case,4.2％) and sympathetic nerve injury (one case,4.2％) in the A group.Donor site pain occurred in four patients (16.0％),thigh numbness/ pain in three patients (12.0％),psoas/quadrieeps weakness in one patient (4.0％) and sympathetic nerve injury in one patient (4.0％) in the B group.All complications were transient and resolved within 3 months.The incidence of complications excluding donor site pain in the early period (A group) and the later period (B group) was 37.5％ and 20.0％,respectively,although there were no significant differences in perioperative complications between both groups.Forty nine patients were followed up for more than 1 year,and the average follow-up period was 18.5±3.9 months.The back pain VAS and ODI scores decreased respectively from 6.4±2.3 before surgery to 1.5±0.9 in final follow-up and from 37.1 ±9.4 before surgery to 11.8±3.9 in the last follow-up time.Total fusion rate was 89.8％ (44/49 cases)in final follow-up.Radiographic evaluation showed similar bony fusion in the A group (22 of 24 cases) with the B group (22 of 25 cases) in the last follow-up time.Conclusion Single level degenerative lumbar diseases can safely and effectively be treated by using OLIF with a good short-term clinical outcome.The procedure presents a learning curve to the practicing spine surgeon with regards to operative time,X-ray exposure time and intra-/postoperative complications.Intraoperative parameters improved with understanding the minimally invasive technique.Close attention to details can minimize complications that may be associated with the learning curve.