The role of cervical collar in functional restoration and fusion after anterior cervical discectomy and fusion without plating on single or double levels: a systematic review and meta-analysis

Purpose: Even though the anterior cervical discectomy and fusion (ACDF) is one of the most common spinal procedures, a consensus on the real need for prescribing a cervical collar (CC) after surgery is still missing. In fact, the role of external immobilization in decreasing non-fusion rate and implants displacement has not been clarified yet. Methods: This study was conducted according to the PRISMA statement. Six different online medical databases were screened. Papers reporting the neck disability index (NDI), cervical range of motion (RoM) and fusion rate after ACDF without plating, on single or multiple levels, for cervical spondylosis were considered for eligibility. Results: There were no significant differences in terms of NDI scores at 2 weeks (WMD = 4.502; 95% CI − 5.953, 14.957; p = 0.399; I2 = 65.14%; p = 0.090) and 1-year (WMD = 2.052; 95% CI − 1.386, 5.490 p = 0.242; I2 = 0%; p = 0.793), RoM reduction at 1-year (WMD = 1.597; 95% CI − 5.886, 9.079; p = 0.676; I2 = 0%; p = 0.326) or fusion rate (OR = 1.127; 95% CI 0.387, 3.282; p = 0.827; I2 = 2.166%; p = 0.360). Conclusions: The use of a CC after ACDF without plating on single or double levels for cervical spondylosis seems not supported by scientific evidence.