Comparison of surgical outcomes after anterior cervical discectomy and fusion: does the intra-operative use of a microscope improve surgical outcomes.

BACKGROUND The primary aim of this study was to assess and compare the complications profile as well as long-term clinical outcomes between patients undergoing an Anterior Cervical Discectomy and Fusion (ACDF) procedure with and without the use of an intra-operative microscope. METHODS One hundred and forty adult patients (non-microscope cohort: 81; microscope cohort: 59) undergoing ACDF at a major academic medical center were included in this study. Enrollment criteria included available demographic, surgical and clinical outcome data. All patients had prospectively collected patient-reported outcomes measures and a minimum 2-year follow-up. Patients completed the neck disability index (NDI), short-form 12 (SF-12) and visual analog pain scale (VAS) before surgery, then at 3, 6, 12, and 24 months after surgery. Clinical outcomes and complication rates were compared between both patient cohorts. RESULTS Baseline characteristics were similar between both cohorts. The mean ± standard deviation duration of surgery was longer in the microscope cohort (microscope: 169±34 minutes vs. non-microscope: 98±42 minutes, P<0.001). There was no significant difference between cohorts in the incidence of nerve root injury (P=0.99) or incidental durotomy (P=0.32). At 3 months post-operatively, both cohorts demonstrated similar improvement in VAS-neck pain (P=0.69), NDI (P=0.86), SF-12 PCS (P=0.84) and SF-12 MCS (P=0.75). At 2-year post-operatively, both the microscope and non-microscope cohorts demonstrated similar improvement from base line in NDI (microscope: 13.52±25.77 vs. non-microscope: 19.51±27.47, P<0.18), SF-12 PCS (microscope: 4.15±26.39 vs. non-microscope: 11.98±22.96, P<0.07), SF-12 MCS (microscope: 9.47±32.38 vs. non-microscope: 16.19±30.44, P<0.21). Interestingly at 2 years, the change in VAS neck pain score was significantly different between cohorts (microscope: 2.22±4.00 vs. non-microscope: 3.69±3.61, P<0.02). CONCLUSIONS Our study demonstrates that the intra-operative use of a microscope does not improve overall surgery-related outcomes, nor does it lead to superior long-term outcomes in pain and functional disability, 2 years after index surgery.