Sciatica or lumbosacral radicular syndrome affects millions of individuals worldwide and is typically caused by disk herniation.¹ The natural course is usually favorable. Surgery is offered to patients with persistent pain that is refractory to conservative treatment.^2-4 Since the first successful lumbar disk operation, described by Mixter and Barr⁵ in 1934, a variety of less invasive techniques have been developed. With the introduction of the microscope, the original laminectomy was refined into open microdiskectomy, which is now the most common procedure.^6-8

The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury. We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up. Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy. In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more low-back pain during the first year after surgery.

BACKGROUND:. Transmuscular tubular diskectomy has been introduced to increase the rate of recovery, although evidence is lacking.OBJECTIVE:. To evalua

Object: Muscle injury is inevitable during surgical exposure of the spine and is quantified by the release of creatine phosphokinase (CPK). No studies have been conducted on different spinal approaches and nonspinal surgery with regard to muscle injury. The present prospective cohort study was conducted to evaluate the results of postoperative serum CPK as an indicator of muscle injury in relation to various spinal and nonspinal procedures. Methods: The authors analyzed data in 322 consecutive patients who had undergone 257 spinal and 65 nonspinal procedures. Primary procedures were performed in 264 patients and revision surgeries in 58. Spinal procedures were subdivided according to the degree of surgical invasiveness as follows: minimally invasive (microendoscopic lumbar discectomy, unilateral transflaval discectomy, and minithoracotomy), average invasiveness (bilateral lumbar discectomy, laminectomy, and anterior cervical discectomy), and extensive surgery (instrumented single or multilevel spondylodesis of the entire spinal column). Spinal localization, number of spinal levels involved, surgical approach, duration of surgery, and body mass index (BMI) were recorded. Creatine phosphokinase was measured before surgery and 1 day after surgery, and the CPK ratio (that is, the difference within one patient) was used as the outcome measure. Results: There was a significant dose-response relationship between the CPK ratio and the degree of surgical invasiveness; extensively invasive surgery had the highest CPK ratio and minimally invasive surgery had the lowest. Thoracolumbar surgery had a significantly higher CPK ratio compared with those for cervical and nonspinal surgery. There was a slightly negative relationship between the number of spinal segments involved and the CPK ratio. The CPK ratio in revision surgery was significantly higher than in primary surgery. Posterior surgical approaches had a higher CPK ratio, and the ratios for unilateral compared with bilateral approaches were not significantly different. The duration of surgery and preoperative serum level of CPK significantly influenced postoperative CPK. There was also a significant association between CPK ratio and nonspinal surgery. Age, sex, and BMI were not significant factors. Conclusions: Data in this study have shown a dose-response relationship between CPK and the extent of surgical invasiveness. Thoracolumbar surgery, posterior approaches, duration of surgery, revision surgery, and preoperative value of CPK were significant influencing factors for the CPK ratio. The clinical significance of the results in the present study is not known.

OBJECTIVE. Vertebral body reconstruction after corpectomy has become a common surgical procedure. The authors describe a prospectively followed case se