Minimally invasive posterior cervical foraminotomy with tubes to prevent undesired fusion: a long-term follow-up study

OBJECTIVE The objective of this study was to compare anterior cervical discectomy and fusion (ACDF) and minimally invasive posterior cervical foraminotomy (MI-PCF) with tubes for the treatment of cervical radiculopathy in terms of the 1) overall revision proportion, 2) index and adjacent level revision rates, and 3) functional outcome scores. METHODS The authors retrospectively reviewed the records of consecutive patients who had undergone ACDF or MI-PCF at a single institution between 2009 and 2014. Patients treated for cervical radiculopathy without myelopathy and with a minimum 2-year follow-up were compared according to the procedure performed for their pathology. Primary outcome measures included the overall rate of revision with fusion and overall revision proportion as well as the rate of index and adjacent level revisions per year. Secondarily, self-reported outcome measures-Neck Disability Index (NDI) and visual analog scale (VAS) for arm (VASa) and neck (VASn) pain-at the preoperative and postoperative evaluations were analyzed. Standard binomial and categorical comparative analyses were performed. RESULTS Forty-nine consecutive patients were treated with MI-PCF, and 210 consecutive patients were treated with ACDF. The mean follow-up for the MI-PCF cohort was 42.9 +/- 6.6 months (mean +/- SD) and for the ACDF cohort was 44.9 +/- 10.3 months. There was no difference in the overall revision proportion between the two cohorts (4 [8.2%] of 49 MI-PCF vs. 12 [5.7%] of 210 ACDF, p = 0.5137). There was no difference in the revision rate per level per year (3.1 vs. 1.7, respectively, p = 0.464). Moreover, there was no difference in the revision rate per level per year at the index level (1.8 vs. 0.7, respectively, p = 0.4657) or at an adjacent level (1.3 vs. 1.1, p = 0.9056). Neither was there a difference between the cohorts as regards the change from preoperative to final postoperative functional outcome scores (NDI, VASa, VASn). CONCLUSIONS Minimally invasive PCF for the treatment of cervical radiculopathy demonstrates rates of revision at the index and adjacent levels similar to those following ACDF. In order to confirm the positive efficacy and cost analysis findings in this study, future studies need to extend the follow-up and show that the rate of revision with fusion does not increase substantially over time.