The Impact of Obesity on Surgical Outcomes Following a Minimally Invasive Lumbar Diskectomy

Presented at SMISS Annual Forum 2014
By Abbas Naqvi BS
With Kern Singh MD, Sreeharsha Nandyala BA, Alejandro Marquez-Lara MD, Islam Elboghdady , Eric Sundberg MD, Hamid Hassanzadeh MD, Anton Jorgensen MD, Mohamed Noureldin MD,

Disclosures: Abbas Naqvi BS None Kern Singh MD A; CSRS Resident Grant. B; DePuy, Zimmer, Stryker, CSRS, ISASS, AAOS, SRS, Vertebral Column - ISASS. D; Avaz Surgical, LLC, Vital 5, LLC. F; Zimmer, Stryker, Pioneer, Lippincott Williams & Wilkins, Th, Sreeharsha Nandyala BA None, Alejandro Marquez-Lara MD None, Islam Elboghdady None, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Mohamed Noureldin MD None,

Introduction:
Lumbar spine procedures in obese patients can be technically demanding and are associated with a greater risk of postoperative complications. MIS techniques offer a consistent surgical exposure regardless of body habitus by virtue of rigid cylindrical retractor systems. Few studies have assessed the surgical parameters and outcomes associated with MIS lumbar diskectomy as they relate to body mass index.

Aims/Objectives:
To compare the surgical outcomes of a minimally invasive (MIS) lumbar diskectomy as a function of obesity.

Methods:
A retrospective analysis of 250 patients who underwent a primary 1 and 2 level lumbar diskectomy for degenerative spinal pathology between 2007-2013 was performed. The patients were divided based upon the body mass index (BMI) (obese (BMI>30Kg/m2) vs non-obese (BMI<30Kg/m2)). Patient demographics, comorbidity Index (CCI), intra-operative parameters, peri-operative outcomes, and postoperative complications were assessed. Statistical analysis was performed with independent sample T tests for continuous variables and Chi-square analysis for categorical data. An alpha level of 0.05). Obese patients incurred a longer operative time (43.9±20.2 vs 37.9±18.8 min; p <0.05), and intraoperative blood loss (43.9±20.3 vs 37.5±12.8 cc; p <0.05). However, a higher BMI was not associated with a greater rate of postoperative complications, length of hospitalization, and rates of re-herniation or revision/reoperation. Obese patients reported greater VAS scores than non-obese patients at 6 weeks (3.1±2.5 vs 2.2±2.4, p<0.05), but this difference did not persist at further follow-up.

Conclusions:
Obese patients who underwent an MIS lumbar diskectomy demonstrated increased procedural times and blood loss when compared to non-obese patients. However, a greater BMI was not associated with an increased incidence of postoperative complications, re-herniations, or revision/reoperations. Furthermore, both cohorts reported similar improvement in clinical symptoms. The small, but statistically significant differences in surgical parameters between cohorts (6 minutes of operative time, and 6.4 cc of blood loss) did not significantly impact patient outcomes. As such, MIS techniques are a safe and effective approach for lumbar diskectomy in obese patients.