C7 or T1/T2: No Difference in Adjacent Segment Reop Rates

Researchers found no difference in reoperation rates for adjacent segment disease in posterior cervical fusions stopping at -C7 Versus -T1/T2.

The study, “No Difference in Reoperation Rates for Adjacent Segment Disease (Operative Adjacent Segment Disease) in Posterior Cervical Fusions Stopping at C7 Versus T1/T2,” is published in the February 01, 2022 issue of the journal Spine.

The retrospective cohort study sought to determine any difference in reoperation rates for adjacent segment disease, operative adjacent segment disease in posterior cervical fusions that stop at –C7 versus –T1/T2.

“There are surgical treatment challenges to the anatomical complexities of the cervicothoracic junction. Current posterior cervical spine surgery is based on the belief that adjacent segment disease occurs if fusions are stopped at C7 although there is varying evidence to support this assumption,” the researchers wrote.

Eight hundred and seventy-five patients with posterior cervical fusions stopping at either -C7 or -T1/T2 were included in the study. They were followed until validated reoperations for adjacent segment disease, membership termination, death, or March 31, 2020.

The researchers reported on descriptive statistics and 5-year crude incidence rates and 95% confidence intervals for operative adjacent segment disease for posterior cervical fusion ending at -C7 or -T1/T2. The average follow-up time was 4.6 years and average time to operative adjacent segment disease was 2.7 (± 2.8) years.

The crude overall incidence rates for stopping at -C7 (2.12% [1.02%-3.86%]) and -T1/T2 (2.48% [1.25%-4.40%]) were comparable with no statistical difference in risk (adjusted hazard ratio = 1.47, 95% confidence interval = 0.61-3.53; p = 0.39). There were also no differences in the probability of operative adjacent segment disease in competing risk time-dependent models (Grey test p = 0.448).

“A large cohort of 875 patients with posterior cervical fusions stopping at -C7 or -T1/T2 with an average follow-up of more than 4 years found no statistical difference in reoperation rates for adjacent segment disease (operative adjacent segment disease),” the researchers wrote.

The study authors included Kern H. Guppy, M.D. of the Permanente Medical Group in Sacrament, CA, Kathryn E. Royse of Surgical Outcomes and Analysis, Kaiser Permanente in San Diego, CA, Jacob Fennessy, M.D. of The Permanente Medical Group, Sacramento, CA, Elizabeth P .Norheim, M.D. of Southern California Permanente Medical Group in Downey, CA, Jessica E. Harris, R.D. of Surgical Outcomes and Analysis, Kaiser Permanente, and Harsimran S. Brara, M.D. of Southern California Permanente Medical Group, Los Angeles, CA.