A study comparing outcomes between obese and nonobese patients with lumbar disc herniation undergoing surgery: a study of the Swedish National Quality Registry of 9979 patients.

ABSTRACT

BACKGROUND: This study aimed to evaluate whether an increasing grade of obesity is associated with inferior outcomes after lumbar disc herniation (LDH) surgery. METHODS: We retrieved data from the Swedish register for spine surgery regarding patients aged 20-64 who underwent LDH surgery from 2006-2016 and had preoperative and one-year postoperative data. A total of 4156 patients were normal weight, 4063 were overweight, 1384 had class I obesity, 317 had class II obesity and 59 had class III obesity ("morbid obesity"). Data included patient satisfaction, improvement in leg pain (assessed using the National Rating Scale; NRS; rating 0-10), disability (assessed using the Oswestry Disability Index; ODI; rating 0-100) and complications. RESULTS: At one year postsurgery, 80% of normal-weight patients, 77% of overweight patients and 74% of obese patients (class I-III evaluated together) were satisfied (p < 0.001) [75%, 71%, 75% in obesity classes I, II, and III, respectively (p = 0.43)]. On average, all groups improved by more than the minimal clinically important difference (MCID) in both NRS leg pain (> 3.5) and ODI (> 20). NRS leg pain improved by 4.8 in normal weight patients (95% CI 4.7-4.9), by 4.5 in overweight patients (4.5-4.6) and by 4.3 in obese patients (4.2-4.4) (p < 0.001) [4.4 (4.3-4.6), 3.8 (3.5-4.1) and 4.6 (3.9-5.3) in obesity classes I, II, and III, respectively (p < 0.001)]. The ODI improved by 30 in normal weight patients (30-31), by 29 in overweight patients (28-29) and by 26 in obese patients (25-27) (p < 0.001) [29 (28-29), 25 (22-27) and 27 (22-32) in obesity classes I, II, and III, respectively (p < 0.01)]. A total of 3.0% of normal-weight patients, 3.9% of overweight patients and 3.9% of obese patients suffered complications (p = 0.047) [3.8%, 4.4%, 3.5% in obesity classes I, II, and III, respectively (p = 0.90)]. CONCLUSIONS: LDH surgery is also generally associated with favourable outcomes and few complications in patients with morbid obesity.