Introduction: Proximal Junctional Kyphosis (PJK) is a common and potentially devastating complication following surgery for adult spinal deformity (ASD). Although proposed prevention strategies include restoration of spinal balance, cement augmentation, and use of softer transitions such as hooks, the effectiveness of these measures has been limited. Recently, we reported that non-mechanical neurological comorbidities play an important role in postoperative sagittal imbalance and PJK. This study was performed to further define the contribution of non-mechanical factors to the occurrence of PJK after ASD.
Methods: We identified a consecutive series of ASD patients who required revision surgery for PJK between 2013 and 2015. A matched cohort of ASD patients that did not develop PJK was identified based upon age, gender, preoperative deformity type and number of fusion levels. We compared medical and surgical histories in the matched cohorts, with particular attention to the prevalence of preoperative neurologic comorbidities that might affect standing balance. Preoperative, immediate postoperative and follow-up radiographs were reviewed to document specific characteristics of mechanical failure that resulted in PJK and required revision surgery.
Results: Twenty-eight cases of PJK requiring revision surgery were identified. The prevalence of pre-operative neurological comorbidities in PJK patients were statistically significantly higher than in non-PJK patients (75% vs. 32%, p < 0.001). Neurological comorbidities included prior stroke (4), metabolic encephalopathy (2), Parkinson’s disease (1), seizure disorder (1), cervical and thoracic myelopathy (7), diabetic neuropathy (4) and other neuropathy (4). The mean preoperative sagittal vertical axis in PJK patients was more positive compared to non-PJK patients (143mm vs. 65mm, p=0.009). There were no significant differences in immediate postoperative or follow-up radiographic parameters between cohorts.
Conclusions: Risk factors identified for the development of PJK included non-mechanical neurological comorbidities, emphasizing the need to look beyond radiographic alignment in order to reduce the incidence of PJK.
Patient Care: Our study showed that ASD patients with neurological comorbidities may have a higher risk of developing PJK after surgical deformity correction. Surgeons should consider neurologic comorbidities, not just radiographic alignment in the surgical treatment of adult spinal deformity and PJK.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Be aware that patients with neurological comorbidities are an “at-risk” population for the development of PJK, 2) Discuss whether that risk can be modified. 3) Look beyond radiographic alignment in order to reduce the incidence of PJK.
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