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Anterior Cervical Discectomy and Fusion

The Surgical Learning Curve

Mayo, Benjamin C. BA; Massel, Dustin H. BS; Bohl, Daniel D. MD, MPH; Long, William W. BA; Modi, Krishna D. BS; Singh, Kern MD

doi: 10.1097/BRS.0000000000001588

Study Design. Case-series

Objective. The aim of the study was to investigate changes in intraoperative and postoperative parameters associated with the surgical learning curve for anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. ACDF is a common surgical spine procedure. The surgical learning curve for this procedure has not been previously characterized.

Methods. A prospectively maintained surgical database of consecutive patients who underwent primary 1–2 level ACDF for degenerative spine disease from 2006 to 2014 was reviewed. Patients with concurrent or revision procedures were excluded. The series began after the surgeon's fellowship and includes his first case as an attending. A total of 374 patients were divided sequentially into cohorts of 125 (early), 125 (middle), and 124 (late). Statistical analyses utilized independent sample t tests, chi squared tests, and multivariate regression adjusted for preoperative characteristics. The learning curve of operative time was characterized using three-parameter asymptotic regression and two separate linear regressions.

Results. The earliest cohort had a greater comorbidity burden, percentage of smokers, and Medicare patients, with fewer workers’ compensation patients when compared to later cohorts. Later cohorts demonstrated decreased mean operative time and estimated blood loss (EBL) and increased arthrodesis rate. Asymptotic and linear regression analyses demonstrated that 50% of the learning curve occurred at case 17 and 31, respectively, whereas 90% of potential improvement occurred by case 56 and 57, respectively.

Conclusion. A significant learning curve exists for surgeons performing ACDFs. Patients undergoing ACDF will experience shorter operations, less EBL, and greater arthrodesis rates as the surgeon gains experience. Operative proficiency can be expected to occur by case 60, with arthrodesis rate increasing over a longer period. These results suggest that despite longer operative times and increased EBL with earlier cases, ACDF can safely and effectively be performed at the onset of a surgeon's career. This conclusion may be useful to new surgeons debating between operative and nonoperative management of cervical degenerative disc disease.

Level of Evidence: 4

Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL.

Address correspondence and reprint requests to Kern Singh, MD, Associate Professor, Department of Orthopedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Suite No. 300, Chicago, IL 60612; E-mail:

Received 22 December, 2015

Revised 1 February, 2016

Accepted 8 March, 2016

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

Relevant financial activities outside the submitted work: grants, royalties.

Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.