Size Does Not Matter: The Impact of Obesity on Surgical Outcomes Following 1 and 2 Level Minimally Invasive Lumbar Laminectomy

Presented at SMISS Annual Forum 2014
By Kern Singh MD
With Sreeharsha V. Nandyala BA, Alejandro Marquez-Lara MD, Islam Elboghdady , Eric Sundberg MD, Hamid Hassanzadeh MD, Anton Jorgensen MD, Aamir Iqbal BS, Mohamed Noureldin MD, Sriram Sankaranarayanan MD,

Disclosures: 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, Aamir Iqbal BS None, Mohamed Noureldin MD None, Sriram Sankaranarayanan MD None,

Introduction:
Some evidence suggests that obese patients may have worsened outcomes following an open lumbar laminectomy owing to greater soft tissue exposure and dissection due to increased body habitus. However, few studies have characterized this relationship as a function of obesity in the setting of MIS techniques.

Aims/Objectives:
To assess perioperative outcomes following a primary 1 and 2 level minimally invasive (MIS) lumbar laminectomy as a function of obesity.

Methods:
A retrospective analysis of 85 patients who underwent a primary 1 and 2 level MIS lumbar laminectomy for degenerative spinal pathology between 2009-2013 was performed. Patients were separated into two cohorts as a function of their body mass index (BMI) (obese (BMI>30Kg/m²) vs non-obese (BMI<30Kg/m²)). Patient demographics, comorbidity Index (CCI), intraoperative parameters, perioperative outcomes, visual analogue scores (VAS), 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 denoted statistical significance.

Results:
85 patients underwent a primary 1 and 2 level MIS lumbar laminectomy of which 32 (37.6%) were classified as obese (mean BMI 36.2±5.2). There were no significant differences in the patient demographics, comorbidity burden, smoking status or the preoperative VAS scores between the cohorts. The obese and non-obese cohorts did not demonstrate significant differences in the procedural time (54.5±22.5 vs 55.2±21.7, p=0.89), estimated blood loss (EBL) (43.1±16.6 vs 43.9±10.9, p=0.79), or the length of hospitalization (22.9±19.6 vs 31.0±30.0, p=0.19). The postoperative VAS scores, incidence of postoperative complications, and rate of revision/reoperations did not significantly differ between cohorts.

Conclusions:
In this retrospective analysis, the operative time, EBL, and length of stay did not significantly vary as a function of obesity during an MIS lumbar laminectomy. These findings of comparable intraoperative variables and hospitalization may be explained by the tubular retractor, which is similar despite body habitus, thereby creating a reproducible surgical environment. In addition to the technical similarity, obesity was not associated with a higher rate of second lumbar decompression or fusion surgery. Unlike open surgery, MIS lumbar laminectomy does not require a different or more extensive surgical exposure, potentially mitigating complications associated with an increased body habitus.