Oral Posters: Values and Outcomes in Spine Surgery

Presented by: A. Araghi - View Audio/Video Presentation (Members Only)


A. Araghi(1), P.D. Klassen(2), C. Thome(3), Anular Closure RCT Study Group

(1) The Core Institute, Phoenix, AZ, United States
(2) St. Bonifatius Hospital, Lingen, Germany
(3) University of Innsbruck, Innsbruck, Austria


Background: Recurrent herniations and readmissions within the early (90 day) post-operative period are major factors driving negative outcomes in lumbar discectomy patients. In addition, early readmission rates are increasingly monitored as a quality metric of clinical performance. Literature reports show the weighted average rate of early lumbar subsequent surgeries index and other levels to be 2.1%. Based on the paper published by Ambrossi, the cost of revision lumbar discectomy is $39,836. It is important to identify contributing risk factors. Carragee et al classified clinical outcomes after primary lumbar discectomy and concluded that patients with large anular defects had a greater rate of reoperation (21%), compared to those having small or slit-type defects (1%). Additionally, Carragee identified this large anular defect group made up 18% of his study cohort. Kim et al confirmed large anular defects to be a risk factor for recurrent herniation, reporting an 18% recurrence rate in a patient population, similar to Carragee's large defect group. The purpose of this study was to evaluate anular defect size and its effect on early reherniation and subsequent readmission in lumbar discectomy patients.

Method: In order to asses if large anular defects are a risk factor for early and recurrent reherniations requiring revision surgery, we compared 90-day reoperation rates in the literature (Group A) to revision rate in a cohort of 278 discectomy patients with anular defects measured intraoperatively in a prospective fashion to be larger than 6 mm (Group B - large anular defect population). The latter were the Control group (discectomy) patients of a multicenter, prospective, randomized trial comparing patients with larger than 6mm anular defects who were randomized to be treated with either discectomy or discectomy and a bone-anchored anular closure device. The width of the anular defect in Group B was assessed with sizing paddles of incremental width. 112 manuscripts were reviewed for the appropriate patient population and data for inclusion in group. 6 manuscripts which reported lumbar reoperations within the first 90 days were used. There were a total of 49,331 patients in these manuscripts.

Results: 13/278 patients from the trial (Group B) underwent 14 (5.0%) reoperations at the index level within 90-days of surgery compared to a 2.1% weighted average rate of spinal reoperations Group A. Comparing data from this prospective discectomy trial ( group A) to the literature (group B), patients who present with large anular defects have more than double the risk of early hospital readmission compared to the general discectomy population.

Conclusion: It is important to note that based on the Caragee data 30-38% of patients in group A would be expected to have large anular defects, and would potentially be already biased to having a recurrent herniation. This would suggest that the rate of recurrent herniation in the group of patients with defects smaller than 6 mm would be even lower than 2.1%.
The intraoperative identification of anular defect size may offer the surgeon an opportunity to risk stratify patients for recurrent herniations, revision surgery and early readmission, potentially lowering hospital costs and preventing negative patient outcomes. This can add up to a significant cost savings at the $39,800 per case.

Literature Review