Clinical Characteristics and Post-surgical Outcomes in Patients with ACIS™ -Anterior Cervical Interbody Spacer (ACIS) Placement in Anterior Cervical Discectomy and Fusion Surgery

Author(s): Abhishek S. Bhutada MD, Kristine Ravina MD, Srijan Adhikari MD, Nanci Dodson MSHS, Jordan Darden PhD, Gregory A. Howes DO

Introduction:

The ACIS™ -Anterior Cervical Interbody Spacer (ACIS, Johnson & Johnson MedTech, Raynham, MA) is a polyetheretherketone (PEEK) cervical cage and is intended for use as intervertebral body fusion device in skeletally mature patients with degenerative disease of the cervical spine (C2–C7). Supplemental fixation is recommended in multi-segmental fusions. Narrowing of the intervertebral height (IH) is an important pathological change in degenerative spinal disease. This study aims to study clinical characteristics, surgical measures and adverse events in patients that received ACIS and VECTRA anterior cervical plate (VECTRA, Johnson & Johnson MedTech, Raynham, MA). It also aims to provide a better understanding of the role that IH plays in clinical outcomes following anterior cervical discectomy and fusion (ACDF).

Methods:

In this retrospective cohort study, patients with degenerative disease of the cervical spine were obtained from the hospital electronic medical records of Carilion Medical Center between 2016 to 2020. Patients that received treatment with ACIS and VECTRA and allograft bone grafting were selected. Information on patient demographics, clinical characteristics, and surgical characteristics was collected. Plain film radiographs were reviewed to evaluate changes in anterior and posterior IH at pre-operative, immediate post-operative, 6-month follow-up visit, and 12-month follow-up visit. A two-tailed T-test was used to identify if there was a statically significant difference in preoperative IH compared to post-operative IH. Radiographic assessment to look for bridging bone was done in order to confirm successful fusion.

Results:

This study included 106 patients. There are 55 males and 51 females. The mean age is 54.4 years and median age is 53 years-old ranging from 26 to 84 years-old . The average body mass index of the population is 31 (95% confidence interval of 18-45). Thirty-one patients never smoked, 35 patients quit over 3 months ago, and 40 patients were current smokers (28%, 32%, and 37%, respectively). Overall, the mean anterior and posterior IH at each post-op visit was significantly greater than pre-op mean anterior and posterior IH (P<0.05). After surgery, a few patients had persistent symptoms of neck pain and swallowing difficulties. In general, the number of patients with swallowing difficulties improved with time; however, the number of patients experiencing neck pain remained constant (Figure 2). Five patients underwent a reoperation procedure, four of which were revision procedures in which supplemental posterior fixation was added to the index vertebral levels. One patient underwent reoperation adjacent to the index levels for treatment of adjacent level disease. Fifty-two of the 56 patients were fused by the 6 month post-op visit and the remaining four patients were fused by the 12 month post-op visit.

Conclusion:

This single center, retrospective cohort study is the first study to look at clinical and surgical factors in patients with degenerative spine disease that were surgically treated with ACIS and VECTRA in single and multilevel ACDF procedures. This study showed that patients received satisfactory fusion as exemplified by radiographic imaging. This study revealed that IH significantly increased post-operatively. Additionally, this difference was sustained throughout all follow-up visits for at least 1 year after surgery.