Crossing the Cervicothoracic Junction During Posterior Cervical Fusion for Myelopathy Is Associated With Superior Radiographic Parameters But Similar Clinical Outcomes

Abstract

Background For laminectomy and posterior spinal fusion (LPSF) surgery for cervical spondylotic myelopathy (CSM), the evidence is unclear as to whether fusions should cross the cervicothoracic junction (CTJ). Objective To compare LPSF outcomes between those with and without lower instrumented vertebrae (LIV) crossing the CTJ. Methods A consecutive series of adults undergoing LPSF for CSM from 2012 to 2018 with a minimum of 12-mo follow-up were identified. LPSF with subaxial upper instrumented vertebrae and LIV between C6 and T2 were included. Clinical and radiographic outcomes were compared. Results A total of 79 patients were included: 46 crossed the CTJ (crossed-CTJ) and 33 did not. The mean follow-up was 22.2 mo (minimum: 12 mo). Crossed-CTJ had higher preoperative C2-7 sagittal vertical axis (cSVA) (33.3 ± 16.0 vs 23.8 ± 12.4 mm, P = .01) but similar preoperative cervical lordosis (CL) and CL minus T1-slope (CL minus T1-slope) (P > .05, both comparisons). The overall reoperation rate was 3.8% (crossed-CTJ: 2.2% vs not-crossed: 6.1%, P = .37). In adjusted analyses, crossed-CTJ was associated with superior cSVA (β = –9.7; P = .002), CL (β = 6.2; P = .04), and CL minus T1-slope (β = –6.6; P = .04), but longer operative times (β = 46.3; P = .001). Crossed- and not-crossed CTJ achieved similar postoperative patient-reported outcomes [Visual Analog Scale (VAS) neck pain, VAS arm pain, Nurick Grade, Modified Japanese Orthopedic Association Scale, Neck Disability Index, and EuroQol-5D] in adjusted multivariable analyses (adjusted P > .05). For the entire cohort, higher postoperative CL was associated with lower postoperative arm pain (adjusted Pearson's r –0.1, P = .02). No postoperative cervical radiographic parameters were associated with neck pain (P > .05). Conclusion Subaxial LPSF for CSM that crossed the CTJ were associated with superior radiographic outcomes for cSVA, CL, and CL minus T1-slope, but longer operative times. There were no differences in neck pain or reoperation rate.

Instrumentation Across the Cervicothoracic Junction Does Not Improve Patient-reported Outcomes in Multilevel Posterior Cervical Decompression and Fusion

“…The proposed advantages of crossing the CTJ include a decreased rate of adjacent segment disease and subsequent need for revision surgery. [7][8][9][10][11][12][13] The average duration of followup in our study was ∼1.8 years. During this time, there was a significant difference in revision surgery rates between groups, but the natural history of adjacent segment disease often occurs after the 2-year follow-up period.…”

“…[22][23][24][25] Furthermore, constructs crossing the CTJ have been associated with increased operative time, increased blood loss, and increased complications. 10,11,26,27 As a result, crossing the CTJ remains controversial in multilevel PCF. In addition, research has been conflicting when evaluating the utility of crossing the CTJ with some studies observing similar revision rates, pain scores, and neurologic function in patients when comparing constructs that do versus those that do not cross the CTJ.…”

“…In addition, research has been conflicting when evaluating the utility of crossing the CTJ with some studies observing similar revision rates, pain scores, and neurologic function in patients when comparing constructs that do versus those that do not cross the CTJ. 10,28 While research has largely focused on revision rates, blood loss, operative time, and postoperative complications, limited studies of patient-reported outcome measures (PROMs) exist comparing constructs crossing versus not crossing the CTJ in patients undergoing PCF. PROMs are one possible tool to assess patients' physical and mental function, quality of life, and pain to evaluate clinical outcomes.…”

Long-segment posterior cervical decompression and fusion: does caudal level affect revision rate?

“…To date, ours is the largest single-center study comparing reoperation rates for cervical spondylotic myelopathy addressed by a subaxial, posterior-only decompression and fusion. Although prior studies have advocated for extension of long-segment fusion to the thoracic spine because of lower rates of revision surgery, pseudarthrosis, or ASD, 14 these studies failed to distinguish between fusions ending at C6 and those ending at C7. We postulated that C6 would have less ASD and pseudarthrosis than C7 fusions because it is a shorter segment requiring fusion and preserves more segmental motion than C7 fusions ending at the biomechanically challenging cervicothoracic junction.…”

“…Some studies suggest that there is a major increase in fusion rates if the construct is extended down to T1-however, there seem to be discrepancies in this evidence throughout the available literature. 9,[13][14][15] The length of the construct has not been reliably found to be associated with the incidence of ASD or pseudarthrosis cases.…”