Introduction: Anterior cervical discectomy and fusion (ACDF) is one of the more commonly performed spinal procedures, with excellent outcomes and very low complication rates. While the intra-operative use of a microscope during this procedure improves visualization, its impact on clinical outcomes remains unclear. Whether the use of a microscope leads superior outcomes remain unknown.

Methods: 140 adult patients (non-microscope cohort: 81 cases, Microscope cohort: 59 cases) undergoing ACDF at Duke University Medical Center by the senior authors (R.I & C.B) 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, Table 1. The median [inter quartile range] number of levels fused was similar between both patient cohorts 2[1-2],p=0.56. The mean±Standard Deviation duration of surgery was longer in the microscope cohort (Microscope cohort:169±34 minutes vs. non-microscope cohort: 98±42 minutes,p<0.001), Table 2. There was no significant difference between cohorts in the incidence of nerve root injury(p=0.99) or incidental durotomy(p=0.32), Table 2. 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), Table 3. These results were durable through 2-years. At 2-years post-operatively, both the microscope and non-microscope cohorts demonstrated similar improvement from base line in NDI (Microscope cohort:13.52±25.77 vs. non-microscope cohort:19.51± 27.47,p<0.18), SF-12 PCS (Microscope cohort:4.15±26.39 vs. non-microscope cohort:11.98±22.96,p<0.07),SF-12 MCS (Microscope cohort: 9.47 ± 32.38 vs. non-microscope cohort:16.19±30.44,p<0.21), Figure 1. Interestingly at 2-years, the change in VAS neck pain score was significantly different between cohorts (Microscope cohort:2.22±4.00 vs. non-microscope cohort:3.69±3.61,p<0.02).

Conclusions: The intra-operative use of a microscope enhances the visualization of surgical anatomy, however, the results of this study indicate that it does not improve overall surgery-related outcomes nor does it lead to superior long-term outcomes in pain and functional disability, tow-years after index surgery

Patient Care: It will improve patient care by allowing surgeons to understand that the the use and extra costs of an intra-operative microscope for ACDF procedures does not lead to more superior outcomes. Therefore, it will allow for a reduction in the extra costs for an intra-operative microscope.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of the use of an intra-operative microscope for ACDF procedures and its relation to superior outcomes, 2) Discuss, in small groups, techniques that utilizes the use of an intra-operative microscope for ACDF procedures, 3) Identify an effective treatment technique with or without the use of an intra-operative microscope that can lead to superior outcomes.

References: 1. Reginald S. Fayssoux, Choll W. Kim. (2013) Minimally invasive decompression. Seminars in Spine Surgery 25, 146-153. 2. Hankinson HL, Wilson CB: Use of the operating microscope in anterior cervical discectomy without fusion. J Neurosurg 43:452-456, 1975 3. Cauthen JC, Kinard RE, Vogler JB, Jackson DE, DePaz OB, Hunter OL, et al: Outcome analysis of noninstrumented anterior cervical discectomy and interbody fusion in 348 patients. Spine (Phila Pa 1976) 23:188-192, 1998 4. Farzad Omidi-Kashani, Ebrahim Ghayem Hasankhani, Reza Ghandehari. (2014) Impact of Age and Duration of Symptoms on Surgical Outcome of Single-Level Microscopic Anterior Cervical Discectomy and Fusion in the Patients with Cervical Spondylotic Radiculopathy. Neuroscience Journal 2014, 1-6.