Failures and revisions in surgery for sagittal imbalance: analysis of factors influencing failure

Abstract

Introduction: Sagittal imbalance is an important risk factor for spinal disability, pain and loss of health related quality of life. Its correction has a positive impact on these outcomes. Still, it is a very aggressive surgery, with a high revision rate. The aim of this study is to analyze the most important causes of failure of surgery for correction of sagittal imbalance.

Design and methods: In this retrospective observational cohort study twelve patients who previously underwent surgery for sagittal imbalance correction were revised in the period 2009-10. We analyzed angular parameters of sagittal balance before and after primary surgery, type of instrumentation, modality of fusion, implant density, instrumented levels, modality of failure, time from first surgery and angular parameters after revision.

Results and conclusion: Causes of failure were insufficient correction, junctional kyphosis, screw loosening and pseudoarthrosis with rod breakage. In every case, patients presented a new onset or a worsening of sagittal imbalance and pain.

Fig. 1

a Preoperative lateral full-spine standing films. Sagittal imbalance with anterior translation of C7 plumbline and increased pelvic tilt. b Fusion T3-Sacrum—insufficient correction of lumbar hypolordosis after fusion T2 to S1 causes persistent anterior C7 plumbline and increased pelvic tilt. c After revision (Fusion T2-Pelvis and L2 PSO) sagittal alignment is restored. Notice intact discs around the L2 osteotomy. 6 mm rods are implanted. d Rod Breakage at 6 months postop. Fracture at L1 resulting in loss of correction. e Rod exchange and anterior fusion around the PSO (XLIF L1–L2 and L2–L3) restore sagittal imbalance and continuity of the anterior column and promote final healing

Fig. 2

a Following short instrumentation and PSO to increase lumbar lordosis (planned lordosis was obtained after first surgery), loss of correction with proximal junctional fracture and kyphosis resulting in axial pain and new imbalance. b Revision surgery included extension to T2, and correction of proximal junctional kyphosis with an excellent clinical outcome

Fig. 3

a Combined failure after insufficient correction of sagittal misaligment (improper distal foundation without pelvic fixation and inadequate lordosis). Failure with pullout at S1 and rod breakage. b Revision surgery with extension of fixation to pelvis, multiple SPOs to increase lordosis at L2–L3–L4 and anterior column reconstruction with XLIF at L3–L4–L5 and PLIF at L5–S1