Should Thoracolumbar Junction Be Always Avoided as Upper Instrumented Vertebra in Long Instrumented Fusion for Adult Spinal Deformity?

Abstract

Study Design. Retrospective study. Objective. The aim of this study was to investigate the risk factors for proximal junctional failure (PJF) following long instrumented fusion stopping at thoracolumbar junction (TLJ) in adult spinal deformity (ASD) and to determine which cases are suitable for TLJ stop without increasing the risk for PJF. Summary of Background Data. PJF following long fusion for ASD is a well-recognized complication that negatively affects clinical outcomes. Generally, the uppermost instrumented vertebra (UIV) at the TLJ is associated with the risk of PJF. Little is known about the risk factors for PJF in case with the UIV at TLJ. Methods. Radiographic and clinical data of 63 consecutive patients who underwent instrumented fusion from sacrum to TLJ (T11, T12, and L1) for the treatment of ASD with a minimum 2-year follow-up were analyzed to identify the risk factors for PJF, which was defined as proximal junctional angle (PJA) ≥20°, fracture at UIV or UIV+1, failure of UIV fixation, myelopathy, or ‘need for proximal extension of fusion. Results. During the average follow-up duration of 51.7 months, PJF developed in 23 patients (36.5%) at a mean of 9.3 months after surgery. Multivariate analysis revealed that age >70 years (odds ratio [OR]: 1.119), osteoporosis (OR: 4.459), and preoperative kyphotic PJA (OR: 1.138) were significant risk factors for the development of PJF. No PJF occurred in 14 patients lacking any risk factors. The last follow-up clinical results were significantly inferior in the PJF group than in the non-PJF group in terms of Oswestry Disability Index and Scoliosis Research Society-22 score. Conclusion. Age >70 years, osteoporosis, and PJA greater 0° were identified as significant risk factors for PJF. Therefore, the TLJ level can be considered as UIV selectively for patients younger than 70 years without osteoporosis and with lordotic preoperative PJA. Level of Evidence: 3

Complications of adult spinal deformity surgery

“…The risk factors for rod breakage are elderly patients, worse ASA score, obesity, long segment fusions, three-column osteotomy, the high sagittal vertical axis (SVA), thoracic kyphosis, over-correction, and sagittal malalignment. [ 44 57 59 61 ]…”

“…Osteoporosis is a risk factor for instrumentation failure. [ 61 ] Screening tests for osteoporosis for elderly patients should be done routinely. [ 5 ]…”

Proximal junctional fractures after long-segment instrumented fusion: comparisons between upper instrumented vertebrae and upper instrumented vertebrae + 1

“…Although the main consensus in the literature agreed that UIV and UIV + 1 fractures that occurred after long instrumented fusion were classified as PJF [ 2 , 3 , 11 , 12 , 22 ], there were similarities and differences in radiographic and clinical features between these two groups. According to the present study, the patients in both groups were osteoporotic as defined by their BMD, had same age and similar BMI/ASA scores/CCI at index surgery.…”

Spinopelvic sagittal imbalance is risky for development of proximal instrumented fracture after posterior instrumentation.

“…Yagi et al observed 113 patients underwent surgical correction for their adult spinal deformities by method of propensity-matched comparison and concluded that low bone-mineral density is a signi cant risk factor to develop PJF [13]. Park et al studied 63 cases underwent posterior instrumented fusion with their UIV at thoracolumbar junction and concluded that older than 70 years old and osteoporosis would increase incidence of PJF [14]. Because primary osteoporosis is positively related to age, it is easy to understand that patient with older age had higher incidence to develop PJF.…”