BACKGROUND: The incidence of symptomatic adjacent segment disease (ASD) after anterior cervical diskectomy and fusion (ACDF) was reported as 2.9%/y in a previous cohort of 374 patients. Few other data corroborate the incidence and natural history of ASD.
OBJECTIVE: To calculate the incidence of ASD after ACDF that required secondary fusion surgery.
METHODS: The retrospective study used an 11-year nationwide database to analyze the incidences. All patients who underwent ACDF for cervical disk diseases were identified through diagnostic and procedure codes. Kaplan-Meier and Cox regression analyses were performed.
RESULTS: From 1997 to 2007, covering 241 800 725.8 person-years, 19 385 patients received ACDF and 568 had ≥ 2 ACDF operations. The incidence of secondary ACDF operations was 7.6 per 1000 person-years. At the end of the 10-year cohort, 94.4% of patients who had received 1 ACDF remained free from secondary ACDF. The average time interval between the first and second ACDF was 23.3 months. After adjustment for comorbidities and socioeconomic status, secondary ACDF operations were more likely performed on male patients (hazard ratio = 1.27; P = .008) 15 to 39 years of age (hazard ratio = 1.45; P = .009) and 40 to 59 years of age (hazard ratio = 1.41, P = .002, respectively).
CONCLUSION: Repeat ACDF surgery for ASD cumulated steadily in an annual incidence of approximately 0.8%, much lower than the reported incidence of symptomatic ASD. However, at the end of this 10-year cohort, a considerable portion of patients (5.6%) received a second operation. Younger and male patients are more likely to receive such second operations.
*Department of Neurosurgery, Neurological Institute
#Department of Radiology
‡‡Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
‡School of Medicine
§Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
‖Department of Ophthalmology, Chang-Gung Memorial Hospital, Linko, Taiwan
¶Department of Medical Informatics, Institute for Medical Biometry and Informatics, Heidelberg University, Heidelberg, Germany
**Institute of Hospital and Health Care Administration, School of Medicine, National Yang-Ming University,Taipei, Taiwan
Correspondence: Yu-Chun Chen, MD, MSc, Institute for Medical Biometry and Informatics, Department of Medical Informatics, Heidelberg University, Im Neuenheimer Feld 305, Heidelberg 69120, Germany. E-mail: email@example.com or Yu-Chun.Chen@med.uni-heidelberg.de
Received November 8, 2010
Accepted July 13, 2011