When are Short Fusions Successful in Cervical Deformity Surgery?

Abstract

Study design: Retrospective review of a prospective cervical deformity (CD) database.

Objective: Determining when shorter fusions can be successful in CD surgery to reduce the extent of the surgical procedure while mitigating complications.

Summary of background data: Multicenter outcomes database of CD patients.

Methods: CD patients were stratified as short fusions (SF: ≤4 levels fused, cervical LIV) or long fusions (LF: >4 levels fused, LIV caudal to C7). Groups were compared in terms of demographics, baseline and 1-year alignment, patient-reported outcome measures (PROMs), and surgical parameters. The data were then reanalyzed after controlling for baseline cervical Sagittal Vertical Axis (cSVA) using propensity score matching. Decision trees were used to identify baseline factors associated with postop alignment failure (1-year cSVA>4 mm or C2S>20°) among SF patients.

Results: 127 patients were analyzed with 100 LF and 27 SF patients. SF had significantly less EBL (131 vs. 1001 mL) and shorter operative time (223min vs. 435 min). At baseline, LF had worse cervical alignment (cSVA=42.6 vs. 23.0 mm) and were more disabled by Neck Disability Index (NDI, 50 vs. 38). After matching by cSVA, the mean baseline cSVA decreased from 42.6 mm to 27.6 mm in the LF group and increased from 23.0 mm to 27.2 mm in the SF group. 71% (n=15) of SF achieved the MCID for NDI vs. 52% (n=11) of LF pts. SF patients with a BL C2S>26° (n=13) were 12.4 times as likely as SF patients with C2S≤26° (n=13) to have post-operative alignment failure (85% vs. 31%, P<.01) and 5.1 times as likely to have a post-operative complication (69% vs. 31%, P<.05).

Conclusions: Although short fusions can result in excellent outcomes with less extensive surgeries, those with more severe deformities may require longer fusions. SF should be avoided in patients with a BL C2S>26° due to the increased risk of complications and realignment failure.

Keywords: Alignment failure; Baseline factors; Blood loss (EBL); C2 slope (C2S); Cervical Sagittal Vertical Axis (cSVA); Cervical deformity (CD); Decision tree analysis; Long fusion (LF); Neck Disability Index (NDI); Operative time; Patient-reported outcomes (PROMs); Postoperative complications; Realignment; Short fusion (SF); Surgical extent.