Patients With Preoperative Cervical Deformity Experience Similar Clinical Outcomes to Those Without Deformity Following 1–3 Level Anterior Cervical Decompression and Fusion

Abstract

Objective: The aim was to compare the outcomes of patients with incompletely corrected cervical deformity against those without deformity following short-segment anterior cervical decompression and fusion for clinically significant radiculopathy or myelopathy.Summary of Background Data: Cervical deformity has increasingly been recognized as a driver of disability and has been linked to worse patient-reported outcomes measures (PROMs) after surgery.Methods: Patients 18 years or above who underwent 1-3 level anterior cervical decompression and fusion to address radiculopathy and/or myelopathy at a single institution between 2014 and 2018 with at least 1 year of PROMs were reviewed. Patients were categorized based on cervical deformity into 2 groups: sagittal vertebral axis (cSVA) ≥ 40 mm as the deformity group, and cSVA <40 mm as the nondeformity group. Patient demographics, surgical parameters, preoperative and postoperative radiographs, and minimum 1-year PROMs were compared.Results: Of the 230 patients, 191 (83%) were in the nondeformity group and 39 (17%) in the deformity group. Patients with deformity were more likely to be male (69.2% vs. 40.3%, P < 0.001) and have a greater body mass index (32.8 vs. 29.7, P = 0.028). The deformity group had significantly greater postoperative cSVA (44.2 vs. 25.1 mm, P < 0.001) but also had significantly greater ΔcSVA (−4.87 vs. 0.25 mm, P = 0.007) than the nondeformity group. Both groups had significant improvements in visual analog scale arm, visual analog scale neck, Short-Form 12 Physical Component Score, and neck disability index (NDI) (P < 0.001). However, the deformity group experienced significantly greater ΔNDI and Δmental component score (MCS)-12 scores (−19.45 vs. −11.11, P = 0.027 and 7.68 vs. 1.32, P = 0.009).Conclusions: Patients with preoperative cervical sagittal deformity experienced relatively greater improvements in NDI and MCS-12 scores than those without preoperative deformity. These results suggest that complete correction of sagittal alignment is not required for patients to achieve significant clinical improvement.Level of Evidence: III.

Sagittal alignment differences on the operating room table compared to preoperative and postoperative imaging in anterior cervical discectomy and fusion

“…[ 7 ] We did find a significant increase in C2-C7 SVA between preoperative and postoperative time points, which also supports previous studies. [ 5 7 22 ] Interestingly, our study was unable to detect differences between preoperative and intraoperative time points, suggesting intraoperative measurements may mask the expected change postoperatively. C2-C7 SVA is a marker for the head position in relation to the cervical spine, and changes in C2-C7 SVA may result from postural compensation to degenerative changes of the cervical spine.…”

“…Whether ACDF increases C2-C7 lordosis is controversial, as numerous studies have demonstrated statistically significant differences between preoperative and postoperative measurements, whereas others have not. [ 4 5 7 8 21 ] Our findings align with a similar study from our institution, which found no differences in C2-C7 lordosis in 230 patients who underwent ACDF. [ 7 ] We did find a significant increase in C2-C7 SVA between preoperative and postoperative time points, which also supports previous studies.…”

“…[ 4 5 7 8 21 ] Our findings align with a similar study from our institution, which found no differences in C2-C7 lordosis in 230 patients who underwent ACDF. [ 7 ] We did find a significant increase in C2-C7 SVA between preoperative and postoperative time points, which also supports previous studies. [ 5 7 22 ] Interestingly, our study was unable to detect differences between preoperative and intraoperative time points, suggesting intraoperative measurements may mask the expected change postoperatively.…”

“…ACDFs can restore some cervical lordosis through intervertebral grafts or cages, but it is controversial if these changes correspond to improvements in clinical outcomes. [ 4 5 6 7 ] However, sagittal malalignment is known to increase the rates of adjacent segment disease, and as a result, significant attention has been aimed toward restoring or maintaining adequate sagittal alignment intraoperatively. [ 8 9 10 ] While previous research has predominantly focused on the lumbar spine including how intraoperative positioning corresponds to changes in the lumbar sagittal alignment, there is limited literature evaluating the effect of intraoperative positioning for cervical spine procedures and if intraoperative radiographs are predictive of postoperative cervical alignment.…”

Defining Cervical Sagittal Plane Deformity – When Are Sagittal Realignment Procedures Necessary in Patients Presenting Primarily With Radiculopathy or Myelopathy?

“…Previous studies have reported that C2–7 SVA > 4 cm is associated with worsened PROs after multilevel posterior cervical deformity surgery [ 29 ], and this criterion is part of the comprehensive cervical spine deformity classification system which was proposed by Ames et al [ 19 ] Although these studies certainly suggest that a C2–7 SVA of < 4 cm may be beneficial to achieve in those undergoing cervical deformity correction, they should not necessarily be interpreted as meaning that all patients with radiculopathy or myelopathy need to have a value < 4 cm to achieve an optimal outcome. By contrast, in a recent study by Karamian et al [ 30 ] of patients undergoing 1–3 level anterior cervical discectomy and fusion, those with a preoperative C2–7 SVA of > 4 cm actually had greater improvement in Neck Disability Index scores postoperatively versus those with a C2–7 SVA < 4 cm, even though the SVA values remained > 4 cm in the former group and < 4 cm in the latter. In other words, in patients with primarily radiculopathy or myelopathy, C2–7 SVA may not necessarily be a major driver of outcomes.…”