Evaluation of multifidus muscle injury in PE-TLIF in the treatment of single-segment lumbar spinal stenosis

English Keywords:Percutaneous endoscopic transforaminal lumbar interbody fusion  Lumbar spinal stenosis  Multifidus muscle

English Abstract:

  【Abstract】 Objectives: To investigate the effects of percutaneous endoscopic transforaminal lumbar interbody fusion(PE-TLIF) on multifidus muscle injury in the treatment of single-segment lumbar spinal stenosis. Methods: A retrospective analysis of 10 patients with single-segment lumbar spinal stenosis in the Beijing Chao-yang Hospital Affiliated to Capital Medical University from March 2017 to October 2018. There were 3 males and 7 females, whose mean age was 59.4±11.5 years old (range, 43-73 years old)． All patients were treated with PE-TLIF. Operation time, intraoperative blood loss, postoperative wound drainage, postoperative bed rest time, complications were recorded. The clinical efficacy was evaluated using the VAS scores of low back pain and leg pain 1 day before surgery and 7 days, 3 and 6 months after surgery, and ODI scores 1 day before surgery and 3, 6 months after surgery. The Bridwell criteria were used to assess bone graft fusion 6 months after surgery. In order to evaluate the damage of the lumbar multifidus muscle, the maximal cross-sectional area(Max-CSA) of the multifidus muscle at the surgical incision and the peak intensity(PI) of sulphur hexafluoride microbubble contrast agent at 1 day before surgery, 7 days, 3 and 6 months after surgerywere calculated, and serum creatine kinase(CK) levels at 1 day before surgery, 1 and 7 days after surgery were also recorded. Results: The average operation time was 292.5±54.0min, the average intraoperative blood loss was 119.0±92.4ml, the average postoperative wound drainage volume 39.5±19.5ml, and the postoperative bed rest time 21.6±3.2h, surgical incision length 8.7±1.8mm. At 6 months follow-up, grade Ⅱ intervertebral fusion was obtained in 7 patients and grade Ⅲ intervertebral fusion was obtained in 3 patients. The VAS-LBP scores of 1 day before surgery, 7 days after surgery, 3 months after surgery, and 6 months after surgery were 7.20±0.78, 4.10±0.73, 1.40±0.51, 1.10±0.87, and VAS-LP scores were 5.90±1.19, 2.20±1.22, 1.10±0.73, 0.90±0.87 respectively. The ODI scores of 1 day before surgery, 3 months after surgery and 6 months after surgery were (53.3±12.1)%, (23.9±8.0)%, and (13.5±6.5)%, respectively. Compared with the pre-operation status, significant differences were detected in the VAS-LBP score, VAS-LP score and ODI scores at the different postoperative time points(P＜0.05). The serum CK levels of 1 day before surgery, 1 days after surgery, and 7 days after surgery were 79.3±30.3U/L, 428.1±78.3U/L, and 96.2±21.4U/L, respectively. Serum CK levels of 1 day after surgery were higher than those before surgery, and the difference was statistically significant(P<0.05), but there was no significant difference between the 7th day post the surgery and the preoperative day(P>0.05). The Max-CSA of 1 day before surgery, 7 days after surgery, 3 months after surgery, and 6 months after surgery were 501.7±127.6mm2, 624.7±101.8mm2, 521.5±60.4mm2, 494.5±62.6mm2, and PI were 2.73±0.71db, 4.61±1.18db, 2.97±0.49db, 2.58±0.34db. Compared with preoperative status, Max-CSA and PI increased on the 7th day after surgery, the difference was statistically significant(P<0.05), but there was no significant difference in Max-CSA and PI at 3, 6 months after surgery(P>0.05). During the follow-up period, all patients had no significant complications. One patient presented transient hyperreflexia of the right knee tendon after surgery. Conclusions: PE-TLIF can achieve good early clinical results in the treatment of single-level lumbar spinal stenosis, with no significant effects on the blood perfusion and morphological changes of multifidus muscle.