RESUMEN
BACKGROUND: Despite numerous studies identifying risk factors for proximal junctional failure (PJF), risk factors for recurrent PJF (R-PJF) are still not well established. Therefore, we aimed to identify the risk factors for R-PJF following adult spinal deformity (ASD) surgery. METHODS: Among 479 patients who underwent ≥5-level fusion surgery for ASD, the focus was on those who experienced R-PJF at any time or did not experience R-PJF during a follow-up duration of ≥1 year. PJF was defined as a proximal junctional angle (PJA) ≥28° plus a difference in PJA ≥22° or performance of revision surgery regardless of PJA degree. The patients were divided into 2 groups according to R-PJF development: no R-PJF and R-PJF groups. Risk factors were evaluated focusing on patient, surgical, and radiographic factors at the index surgery as well as at the revision surgery. RESULTS: Of the 60 patients in the final study cohort, 24 (40%) experienced R-PJF. Significant risk factors included greater postoperative sagittal vertical axis (OR = 1.044), overcorrection relative to age-adjusted pelvic incidence-lumbar lordosis (PI-LL; OR = 7.794) at the index surgery, a greater total sum of the proximal junctional kyphosis severity scale (OR = 1.145), and no use of the upper instrumented vertebra cement (OR = 5.494) at the revision surgery. CONCLUSIONS: We revealed that the greater postoperative sagittal vertical axis and overcorrection relative to age-adjusted pelvic incidence-lumbar lordosis at the index surgery, a greater proximal junctional kyphosis severity scale score, and no use of upper instrumented vertebra cement at the revision surgery were significant risk factors for R-PJF. CLINICAL RELEVANCE: To reduce the risk of R-PJF after ASD surgery, avoiding under- and overcorrection during the initial surgery is recommended. Additionally, close assessment of the severity of PJF with timely intervention is crucial, and cement augmentation should be considered during revision surgery.
RESUMEN
OBJECTIVE: Score on the proximal junctional kyphosis severity scale (PJKSS) has been validated to show good correlations with likelihood of revision surgery for proximal junctional failure (PJF) after surgical treatment of adult spinal deformity (ASD). However, if the patient has progressive neurological deterioration, revision surgery should be considered regardless of severity based on PJKSS score. This study aimed to revalidate the correlation of PJKSS score with likelihood of revision surgery in patients with PJF but without neurological deficit. In addition, the authors provide the cutoff score on PJKSS that indicates need for revision surgery. METHODS: A retrospective study was performed. Among 360 patients who underwent fusion of more than 4 segments including the sacrum, 83 patients who developed PJF without acute neurological deficit were included. Thirty patients underwent revision surgery (R group) and 53 patients did not undergo revision surgery (NR group). All components of PJKSS and variables other than those included in PJKSS were compared between groups. The cutoff score on PJKSS that indicated need for revision surgery was calculated with receiver operating characteristic curve analysis. Multivariate analysis with logistic regression was performed to identify which variables were most predictive of revision surgery. RESULTS: The mean patient age at the time of index surgery was 69.4 years, and the mean fusion length was 6.1 segments. All components of PJKSS, such as focal pain, instrumentation problem, change in kyphosis, fracture at the uppermost instrumented vertebra (UIV)/UIV+1, and level of UIV, were significantly different between groups. The average total PJKSS score was significantly greater in the R group than in the NR group (6.0 vs 3.9, p < 0.001). The calculated cutoff score was 4.5, with 70% sensitivity and specificity. There were no significant between-group differences in patient, surgical, and radiographic factors (other than the PJKSS components). Three factors were significantly associated with revision surgery on multivariate analysis: instrumentation problem (OR 8.160, p = 0.004), change in kyphosis (OR 4.809, p = 0.026), and UIV/UIV+1 fracture (OR 6.462, p = 0.002). CONCLUSIONS: PJKSS score positively predicted need for revision surgery in patients with PJF who were neurologically intact. The calculated cutoff score on PJKSS that indicated need for revision surgery was 4.5, with 70% sensitivity and specificity. The factor most responsible for revision surgery was bony failure with > 20° focal kyphotic deformity. Therefore, early revision surgery should be considered for these patients even in the absence of neurological deficit.