Minimally Invasive Surgery for Revision Lumbar Diskectomy Procedures

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

Disclosures: Islam Elboghdady 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, Eric Sundberg MD None, Abbas Naqvi BS None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Khaled Aboushaala MD None, Blaine Manning BS None,

Introduction:
Traditionally, revision lumbar spine procedures are associated with greater surgical exposures resulting in longer operations and greater soft tissue disruption. However, few studies have analyzed the surgical parameters and postoperative outcomes associated with MIS revision lumbar diskectomies.

Aims/Objectives:
To compare the intraoperative parameters and surgical outcomes between primary and revision 1 and 2 level minimally invasive (MIS) lumbar diskectomies.

Methods:
A retrospective analysis of 298 patients who underwent an MIS 1 and 2 level lumbar diskectomy for degenerative spinal pathology between 2009-2013 was performed. The patients were divided between primary and revision cohorts. 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 denoted statistical significance.

Results:
There were 298 patients who underwent an MIS lumbar diskectomy of which 46 (15.4%) were revision procedures. Patient demographics, comorbidity burden, smoking status and preoperative visual analogue scale (VAS) scores were comparable between cohorts. Procedural time (43.1±15.5 vs 40.4±19.5 min, p=0.63), estimated blood loss (37.6±15.0 vs 39.2±14.6 cc, p=0.49), hospitalization (15.0±15.4 vs 13.9±14.4 hours, p=0.12), and the incidence of postoperative complications did not significantly differ between the revision and primary cohorts. In addition, VAS scores were comparable between cohorts. Patients who underwent a revision MIS diskectomy demonstrated a significantly greater incidence of re-herniation (12.8% vs 5.2%, p<0.05) and revisions/reoperations (28.3% vs 14.3%, p<0.05).

Conclusions:
In this analysis, MIS revision lumbar diskectomies were associated with comparable intraoperative parameters when compared to primary procedures. The primary and revision cohorts reported similar clinical improvement, however, the revision cohort demonstrated a greater rate of re-herniation and nearly 1 out of every 3 patients required a revision or reoperation. These findings are likely explained by the complexity of revision procedures and the greater risk of iatrogenic instability following revision lumbar decompression.