Development of Symptomatic Adjacent and Remote Level Compression Fractures Following Balloon-assisted Kyphoplasty in a Series of 1,318 Patients.

BACKGROUND: Balloon-assisted kyphoplasty (BAK) is a minimally invasive procedure to treat vertebral compression fractures (VCF). BAK not only restores vertebral height and corrects kyphotic deformity by cement augmentation, but it also may alter spinal biomechanics, leading to subsequent adjacent level VCFs. OBJECTIVES: This study aims to investigate the timing, location, and incidence of new VCFs following BAK and identify the risk factors associated with their occurrence. STUDY DESIGN: Single-institution observational study. METHODS: A prospectively collected cohort of 1,318 patients who underwent BAK by a single-surgeon from 2001 through 2022 was analyzed. The patients had pain that was unresponsive to nonsurgical management and a VCF secondary to osteoporosis, trauma, or neoplasm. The time between the index and subsequent fracture, fracture level, number of initial fractures, age, body mass index (BMI), tobacco use, and chronic corticosteroid use were recorded. RESULTS: Of 1,318 patients, 204 (15.5%) patients underwent a second BAK procedure an average of 373 days following BAK (range: 2-3,235 days). Third, fourth, and fifth procedures were less common (45, 12, and 6 patients, respectively). A total of 142 patients (69.6%) developed a subsequent fracture adjacent to the index level; adjacent and remote level fractures developed at different times (mean: 282 vs 581 days, P = 0.001). Patients treated for multiple VCFs in a single surgery were more likely to develop subsequent VCFs (P = 0.024) and at adjacent levels (P = 0.007). Subsequent VCFs were associated with older age (P < 0.001), women (P = 0.045), osteoporosis (P < 0.001), and chronic corticosteroid use (P < 0.001). A subgroup analysis of 812 (61.6%) patients who underwent BAK for degenerative indications revealed that osteoporosis (b = 0.09; 95% CI, 0.03-0.16; P = 0.005) and chronic corticosteroid use (b = 0.06; 95% CI, 0-0.11; P = 0.055) were associated with adjacent level fracture. For the entire cohort, almost every patient treated for both a thoracic and lumbar fracture (92.3%) developed an adjacent level second fracture (P = 0.005). LIMITATIONS: The true incidence of post-BAK fractures may be underestimated as surveillance is not routine in asymptomatic or osteoporotic patients. CONCLUSIONS: Symptomatic post-BAK VCFs are infrequent and may occur long after the initial procedure. Nearly two-thirds of subsequent fractures in our study occurred adjacent to the initially treated level; almost every patient who suffered thoracic and lumbar fractures at the same time developed an adjacent level second fracture. Additionally, osteoporosis and chronic corticosteroid use were associated with adjacent level fractures in patients who underwent surgery for degenerative indications.

Analysis of injected cement volume and clinical outcomes following balloon-assisted kyphoplasty in a series of 368 patients.

OBJECTIVE: Balloon-assisted kyphoplasty (BAK) is a modified vertebroplasty technique developed to treat vertebral compression fractures (VCFs) secondary to osteoporosis. This study investigates the association between injected cement volume and the development of subsequent VCFs after BAK. METHODS: A retrospective analysis of 368 patients who underwent BAK at a single institution was performed from 2001 to 2021. Inclusion was defined by at least 2 years of follow-up. Clinical characteristics and outcomes following BAK, including subsequent fractures at adjacent and remote levels, were identified. Patients that underwent a thoracic BAK were stratified by injected cement volume: below or equal to the median (≤ 6.0 mL, 265 vertebrae) or above the median (> 6.0 mL, 144 vertebrae). Patients that underwent a lumbar BAK were similarly stratified: below or equal to the median (≤ 8.0 mL, 233 vertebrae) or above the median (>8.0 mL, 160 vertebrae). RESULTS: A total of 802 vertebrae were treated. The average volume of cement was recorded in the thoracic (6.2 ± 1.9 mL) and lumbar (7.8 ± 1.8 mL) vertebrae. In the thoracic spine, vertebrae that were injected with > 6.0 mL of cement underwent a greater change in local kyphotic angle (P = 0.0001) and were more likely to develop adjacent-level VCFs (P = 0.032) after kyphoplasty. Univariate analysis did not elucidate any additional risk factors. There were no statistical differences in clinical outcomes between the three groups of lumbar vertebrae. CONCLUSIONS: Larger volumes of injected cement were associated with a greater change in local kyphosis and subsequent adjacent-level fractures after BAK in the thoracic spine. This association was not found in the lumbar spine. Close attention to injected cement volumes must be made in the thoracic spine and patients who undergo significant kyphotic correction should be carefully observed postoperatively.

Prediction of 30-day and 1-year postoperative complications after balloon-assisted kyphoplasty in the elderly using the Risk Analysis Index.

OBJECTIVE: Vertebral compression fracture (VCF) is the most prevalent fragility fracture. When conservative management fails, patients may undergo balloon-assisted kyphoplasty (BAK). In BAK, an expandable balloon preforms a cavity in the fractured vertebra before injection of bone cement. The aim of this study was to compare outcomes in patients stratified by age and frailty assessed by the Risk Analysis Index (RAI). METHODS: A retrospective analysis of 334 BAK procedures (280 patients) for osteoporotic VCFs at a single institution was performed (2015-2022). Patients with at least 1 year of follow-up were eligible for inclusion. Patient demographics were recorded, including age, sex, BMI, RAI score, tobacco and steroid use, osteoporosis treatments, and bone density. Patients who underwent outpatient surgery were identified, and length of stay (LOS) was obtained for admitted patients. The rates of additional VCFs after kyphoplasty, 30-day and 1-year postoperative complications, and reoperation were identified. RESULTS: The overall rates of additional VCFs, 30-day postoperative complications, 1-year postoperative complications, and reoperation were 16.2%, 5.1%, 12.0%, and 6.3%, respectively. Patients were stratified by age: nonelderly (< 80 years; 220 patients, 263 treated vertebrae) and elderly (≥ 80 years; 60 patients, 71 treated vertebrae). There were no differences in sex (p = 0.593), tobacco use (p = 0.973), chronic steroid use (p = 0.794), treatment for osteoporosis (p = 0.537), bone density (p = 0.056), outpatient procedure (p = 0.273), and inpatient LOS (p = 0.661) between both groups. There were also no differences in the development of additional VCFs (p = 0.862) at an adjacent level (p = 0.739) or remote level (p = 0.814), 30-day and 1-year postoperative complications (p = 0.794 and p = 0.560, respectively), and reoperation rates (p = 0.420). Patients were then analyzed by RAI: nonfrail (RAI score < 30; 203 patients, 243 treated vertebrae) and frail (RAI score ≥ 31; 77 patients, 91 treated vertebrae). There were no differences in tobacco use (p = 0.959), chronic steroid use (p = 0.658), treatment for osteoporosis (p = 0.560), bone density (p = 0.339), outpatient procedure (p = 0.241), inpatient LOS (p = 0.570), and development of additional VCFs (p = 0.773) at an adjacent level (p = 0.390) or remote level (p = 0.689). However, rates of 30-day and 1-year postoperative complications in frail patients more than doubled in comparison with nonfrail patients (p = 0.031 and p = 0.007, respectively), and frail patients trended toward reoperation (p = 0.097). CONCLUSIONS: BAK is a safe treatment in the elderly, and age alone should not be used as an exclusion criterion during patient selection. Frailty, which can be assessed reliably using the RAI, may serve as a better predictor for postoperative complications and reoperation following BAK.