Morbidly Obese Patients Have Similar Clinical Outcomes and Recovery Kinetics After Minimally Invasive Decompression.

Abstract

Study design: Retrospective cohort.

Objective: To study the impact of class 2/3 obesity (body mass index, BMI ≥35) on outcomes following minimally invasive decompression.

Summary of background data: No previous study has analyzed the impact of class 2/3 obesity on outcomes following minimally invasive decompression.

Materials and methods: Patients who underwent primary minimally invasive decompression were divided into four cohorts based on their BMI: normal (BMI: 18.5-<25), overweight (25-<30), class 1 obesity (30-<35), and class 2/3 obesity (BMI ≥35). Outcome measures were: 1) intraoperative variables: operative time, estimated blood loss (EBL); 2) patient-reported outcome measures (PROMs) (Oswestry disability index, ODI; visual analog scale, VAS back and leg; 12-Item Short Form Survey Physical Component Score, SF-12 PCS); 3) global rating change (GRC), minimal clinically important difference (MCID), and patient acceptable symptom state (PASS) achievement rates; 4) return to activities; and 5) complication and reoperation rates.

Results: Totally, 838 patients were included (226 normal, 357 overweight, 179 class 1 obesity, and 76 class 2/3 obesity). Class 1 and 2/3 obesity groups had significantly greater operative times compared with the other groups. Class 2/3 obesity group had worse ODI, VAS back and SF-12 PCS preoperatively, worse ODI, VAS back, VAS leg and SF-12 PCS at below six months, and worse ODI and SF-12 PCS at above six months. However, they had significant improvement in all PROMs at both postoperative timepoints and the magnitude of improvement was similar to other groups. No significant differences were found in MCID and PASS achievement rates, likelihood of betterment on the GRC scale, return to activities, and complication/reoperation rates.

Conclusions: Class 2/3 obese patients have worse PROMs preoperatively and postoperatively. However, they show similar improvement in PROMs, MCID and PASS achievement rates, likelihood of betterment, recovery kinetics, and complication/reoperation rates as other BMI groups following minimally invasive decompression.