Relationship between number of radiological risk factors for delayed union after osteoporotic vertebral fracture and clinical outcomes.

This study demonstrated that number of three specific radiological risk factors (MR T2WI confined high-intensity pattern and diffuse low-intensity pattern, thoracolumbar vertebrae involvement, middle column injury) added prognostic information for delayed union, kyphotic deformity, and prolonged pain. PURPOSE: Delayed union after osteoporotic vertebral fracture (OVF) causes prolonged pain, QOL impairment, progression of collapse, kyphotic deformity, and neurologic impairment. Some specific radiological findings can be useful for predicting delayed union. We aimed to explore the prevalence and concomitance of various types of radiological risk factors for delayed union after osteoporotic vertebral fracture (OVF) and to assess the impact of risk factor number on clinical outcomes. METHODS: A total of 508 patients with fresh OVF from 25 institutes were evaluated. All patients were treated conservatively without surgical interventions. At the 6-month follow-up, the patients were classified into bone union and delayed union groups based on plain X-ray findings. We examined the presence and absence of three specific radiological risk factors (MR T2WI confined high-intensity pattern and diffuse low-intensity pattern, thoracolumbar vertebrae involvement, middle column injury) and analyzed clinical outcomes according to numbers of radiological risk factors. RESULTS: Delayed union was observed in 101 patients (19.9%) at the 6-month follow-up. The most common radiological risk factor was thoracolumbar vertebrae involvement (73.8%), followed by middle column injury (33.9%) and specific MRI findings (T2WI confined high-intensity pattern and diffuse low-intensity pattern) (29.7%). Overall, 85 (16.7%) patients had zero radiological risk factors, 212 (42.7%) had one, 137 (27.0%) had two, and 69 (13.6%) had three. When assessing the number of radiographic risk factors which included the MRI findings (the 3-risk factor method), the odds ratio for delayed union after acute OVF was 5.8 in the 2/3-risk factor group and 13.1 in the 3/3-risk factor group. Even when assessing the number of radiographic risk factors without MRI findings (2-risk factor method), the odds ratio was 3.2 in the 1/2-risk factor group and 10.2 in the 2/2-risk factor group. CONCLUSION: Number of radiological risk factors added prognostic information for delayed union, kyphotic deformity, and prolonged pain.

Impact of paravertebral muscle in thoracolumbar and lower lumbar regions on outcomes following osteoporotic vertebral fracture: a multicenter cohort study.

We investigated the effect of paravertebral muscle (PVM) on poor prognosis in osteoporotic vertebral fracture (OVF) and remaining lower back pain (LBP) in the thoracolumbar and lower lumbar regions. Additional OVF occurrence in the thoracolumbar and remaining LBP in the lumbar region was significantly related to PVM fat infiltration percentage. PURPOSE: Paravertebral muscle (PVM) is an important component of the spinal column. However, its role in the healing process after osteoporotic vertebral fracture (OVF) is unclear. This study aimed to clarify the effect of PVM in thoracolumbar and lower lumbar regions on OVF clinical and radiological outcomes. METHODS: This was a multicenter prospective cohort study from 2012 to 2015. Patients ≥ 65 years old who presented within 2 weeks after fracture onset were followed up for 6 months. PVM was measured at the upper edge of the L1 and L5 vertebral body in the magnetic resonance imaging (MRI) T2-axial position at registration. The cross-sectional area (CSA), relative CSA (rCSA), and fat infiltration percentage (FI%) were measured. Severe vertebral compression, delayed union, new OVF, and remaining low back pain (LBP) were analyzed. RESULTS: Among 153 patients who were followed up for 6 months, 117 with measurable PVM were analyzed. Their average age was 79.1 ± 7.2 years, and 94 were women (80.3%). There were 48 cases of severe vertebral compression, 21 delayed unions, 11 new OVF, and 27 remaining LBP. Among all poor prognoses, only the FI% of the PVM was significantly associated with new OVF (p = 0.047) in the thoracolumbar region and remaining LBP (p = 0.042) in the lumbar region. CONCLUSION: The occurrence of additional OVF in the thoracolumbar region and remaining LBP in the lumbar region was significantly related to the FI% of the PVM. Physicians should be aware that patients with such fatty degeneration shown in acute MRI may require stronger treatment.

Characteristic radiological findings for revision surgery after balloon kyphoplasty.

Balloon kyphoplasty (BKP) sometimes fails to improve patients' outcomes, with revision surgery, using anterior or posterior reconstruction, being required. The purpose of this study was to investigate the radiological risk factors of failure after BKP in the treatment of osteoporotic vertebral fractures (OVFs). This case-control study included 105 patients treated with single BKP and 14 patients  who required revision BKP. We evaluated radiological findings differentiating both groups, using plain radiography and computed tomography, before BKP. Angular flexion-extension motion was significantly greater in the revision than BKP group. While the frequency of pedicle fracture and posterior wall injury was not different between the groups, a split type fracture was more frequent in the revision group. Split type fracture had the highest adjusted odds ratio (OR) for revision (16.5, p = 0.018). Angular motion ≥14° increased the risk for revision surgery by 6-fold (p = 0.013), with endplate deficit having an OR of revision of 5.0 (p = 0.032). The revision rate after BKP was 3.8%, with split type fracture, greater angular motion and large endplate deficit being risk factors for revision. Treatment strategies for patients with these risk factors should be carefully evaluated, considering the inherent difficulties in performing revision surgery after BKP.

Development of a scoring system for predicting adjacent vertebral fracture after balloon kyphoplasty.

BACKGROUND CONTEXT: The incidence of adjacent vertebral fracture (AVFs) is reported to be 10%-38% after balloon kyphoplasty. However, no reports have established a system for prediction of AVF occurrence. PURPOSE: To establish a scoring system for predicting AVF occurrence after balloon kyphoplasty for osteoporotic vertebral fractures (OVFs). DESIGN: A prospective cohort study. PATIENT SAMPLE: Consecutive elderly patients aged 65 years and older who underwent balloon kyphoplasty for OVFs within 2 months after the onset. OUTCOME MEASURES: AVF was confirmed by X-ray. METHODS: From 2015 to 2017, 116 consecutive patients from 10 participating hospitals who underwent balloon kyphoplasty were enrolled in this study. Prior to study enrollment, each patient underwent plain X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the thoracic and lumbar spine. Severity of pain was subjectively assessed using a visual analog scale (VAS) based on the average level of back pain that the patient had experienced in the preceding week. After enrollment, subjects underwent balloon kyphoplasty. Quality of life was evaluated using SF-36. Patients were followed up for at least 6 months. RESULTS: Of the 116 patients enrolled, 109 patients with all the required data at the time of enrolment and the 6-month follow-up were included in the study. A total of 32 patients (29%) showed AVFs within the 6-month follow-up. No significant differences were observed in each clinical outcome at 6-month follow-up, although higher VAS score for back pain at 1-month follow-up was observed in the AVF group (37.5) than in the non-AVF group (20.8, p<.001). Wedge angle of vertebrae before surgery was greater in the AVF group (21.6°) than in the non-AVF group (15.7°, p<.001). The change in wedge angle between pre- and postsurgery was greater in the AVF group than in the non-AVF group, whereas the change in local kyphosis was not significantly different. The multiple logistic regression model showed increased odds ratio (OR) of thoracic or thoracolumbar spine, old OVF presence, >25° kyphosis before surgery, and >10°correction for AVF. Based on this result, a simple scoring system for predicting AVF occurrence was developed. The total AVF score was calculated as the sum of the individual scores, which varied from 0 to 6. All patients with 5-6 points sustained AVF. CONCLUSIONS: More severe wedge angle before surgery, correction degree, old OVF presence, and thoracolumbar level were predictive factors for AVF. All patients with AVF risk score of 5 or more showed AVF. This information may aid preoperative risk assessment, informed shared decision-making, and consideration of potential alternative management strategies.

Association between MRI findings and back pain after osteoporotic vertebral fractures: a multicenter prospective cohort study.

BACKGROUND CONTEXT: Osteoprotic vertebral fractures (OVFs) are common in elderly people. The association between back pain due to OVF with magnetic resonance imaging (MRI) signal change is unclear. In this study we hypothesized that MRI findings would be a predictive factor for back pain measured by visual analogue scale (VAS) at 6 months follow-up. PURPOSE: The aim was to study the MRI findings that predict back pain after OVF and the association between radiological findings and scores of back pain. STUDY DESIGN: Multicenter prospective cohort study. PATIENT SAMPLE: A total of 153 OVF patients. OUTCOME MEASURE: The outcome measures were VAS back pain and MRI signal change. METHODS: This study was performed from 2012 to 2015. Consecutive patients with less than 2-week-old OVFs at 11 institutions were enrolled prospectively. MRI was performed at enrollment and at 1, 3, and 6 months follow-up. T1- and T2-weighted images (T1WI and T2W1) were obtained at each time point and their association with VAS scores of back pain at 6 months were investigated. Anterior compression ratio, posterior compression ratio, and angular motion of vertebral bodies were also measured on X-rays at each follow-up. This research had no financial support. There are no conflicts of interest. RESULT: The 6 months follow-up was completed by 153 patients. At enrollment, the average VAS score of back pain was 75 mm, and it had improved at the 6-month follow-up to an average score of 20 mm. There was a significant correlation between T1 diffuse low signal change and VAS scores at the 6-month follow-up (p<.01). T2 high signal changes (odds ratio; 4.01, p<.01) and old vertebral fractures (odds ratio; 2.47, p=.04) were independent risk factors for back pain. The correlation between angular motion of vertebrae on X-rays and the VAS score of back pain was significant at all time points. CONCLUSION: This study demonstrates the radiological factors associated with persistent back pain after an OVF and the association between the VAS score of back pain and radiological findings. In addition, T2 high signal changes in acute phase and old vertebral fractures were independent risk factors for residual back pain.

Cost-effectiveness of Balloon Kyphoplasty for Patients With Acute/Subacute Osteoporotic Vertebral Fractures in the Super-Aging Japanese Society.

STUDY DESIGN: A propensity score matching study. OBJECTIVE: The aim of this study was to assess the cost-effectiveness of balloon kyphoplasty (BKP) in Japan. SUMMARY OF BACKGROUND DATA: Osteoporotic vertebral fracture (OVF) is a common disease in elderly people. In Japan, the incidence of painful OVF in 2008 was estimated as 880,000, and approximately 40% of patients with painful OVF are hospitalized due to the severity of pain. Japan is the front runner among super-aged societies and rising health care costs are an economic problem. METHODS: BKP and nonsurgical management (NSM) for acute/subacute OVF were performed in 116 and 420 cases, respectively. Quality-adjusted life years (QALY) and incremental costs were calculated on the basis of a propensity score matching study. QALY was evaluated using the SF-6D questionnaire. Finally, using a Markov model, incremental cost-effectiveness ratios (ICERs) were calculated for 71 matched cases. RESULTS: In the comparison between BKP and NSM, mean patients age was 78.3 and 77.7 years, respectively (P = 0.456). The BKP procedure cost 402,988 JPY more than NSM and the gains in QALY at the 6-month follow-up were 0.153 and 0.120, respectively (difference = 0.033). ICERs for 3 and 20 years were 4,404,158 JPY and 2,416,406 JPY, respectively. According to sensitivity analysis, ICERs ranged from 652,181 JPY to 4,896,645 JPY (4418-33,168 GBP). CONCLUSION: This study demonstrated that BKP is a cost-effective treatment option for OVF in Japan. However, the effect might be blunted in patients aged > 80 years. Further research is necessary to elucidate the cost-effectiveness of BKP in this population. LEVEL OF EVIDENCE: 4.

Balloon Kyphoplasty Versus Conservative Treatment for Acute Osteoporotic Vertebral Fractures With Poor Prognostic Factors: Propensity Score Matched Analysis Using Data From Two Prospective Multicenter Studies.

STUDY DESIGN: A multicenter, prospective, single-arm, intervention study. OBJECTIVE: The aim of this study was to investigate efficacy of balloon kyphoplasty (BKP) for acute osteoporotic vertebral fractures (OVFs) in patients with poor prognostic factors. SUMMARY OF BACKGROUND DATA: The indications for BKP remain unclear. Characteristic magnetic resonance imaging (MRI) findings (high-intensity or diffuse low-intensity area in fractured vertebrae on T2-weighted images) were reportedly predictive of delayed union. METHODS: This study enrolled 106 patients with poor prognostic MRI findings who underwent BKP within 2 months after injury, and 116 controls with acute OVFs and the same poor prognostic factors who underwent conservative treatment. Patients were propensity score matched in a logistic regression model adjusted for age, sex, number of baseline old fractures, and fracture level. The primary outcome was reduction in activities of daily living (ADLs) at 6 months after fracture, and the secondary outcomes were improvement in short-form (SF)-36 subscales, back pain visual analog scale (VAS) score, and vertebral body deformity. RESULTS: A decrease in ADLs occurred in 5.6% of patients in the BKP group and 25.6% of patients in the conservative treatment group (P < 0.001). The SF-36 vitality subscale score improved by 26.9 ±â€Š25.9 points in the BKP group and 14.5 ±â€Š29.4 points in the control group (P = 0.03). The VAS pain score improved by 43.4 ±â€Š34.4 in the BKP group and 52.2 ±â€Š29.8 in the control group (P = 0.44). The vertebral body wedge angle improved by 5.5 ±â€Š6.2° in the BKP group and -6.3 ±â€Š5.0° in the control group (P < 0.0001). The percent vertebral body height improved by 15.2 ±â€Š19.2% in the BKP group and -20.6 ±â€Š14.2% in the control group (P < 0.0001). CONCLUSION: ADLs, quality of life, and vertebral deformity showed greater improvement with BKP intervention for acute OVF with poor prognostic factors than with conservative treatment at 6 months after injury. Our treatment strategy uses BKP intervention according to the presence or absence of poor prognostic MRI findings. LEVEL OF EVIDENCE: 4.

The degeneration of adjacent intervertebral discs negatively influence union rate of osteoporotic vertebral fracture: A multicenter cohort study.

BACKGROUND: With the increasing aging population in developed countries, there has been an associated increased prevalence of osteoporotic vertebral fracture (OVF). Many previous reports have attempted to predict the risk of delayed union associated with OVF. However, the role of endplate failure and the degeneration of adjacent intervertebral discs, and their association with delayed union has received little attention. The aim of this study was to evaluate the endplate fracture and disc degeneration rank as risk factors for delayed union. MATERIALS AND METHODS: Two hundred and eighteen consecutive patients with fresh OVF were enrolled in the study. MRI and X-ray were performed at the time of enrollment and at the 6 months follow-up. The MR images were used to assess the degeneration grade of adjacent intervertebral discs (using the modified Pfirrmann grading system), and endplate failure. Supine and weight-bearing radiographs were used to define angular motion and compression ratio of the anterior vertebral body wall. RESULTS: A total of 139 patients (112 female, 27 male) completed the 6 month follow-up (a 65.1% follow-up rate). The study revealed 27 cases of delayed union (19.4%). A healthier adjacent caudal disc with low grade degeneration was found to be associated with an increased risk of delayed union (P = 0.008). Bi-endplate injury and significant compression of the anterior vertebral body wall were significantly associated with delayed union (P = 0.019, and P = 0.001 respectively). Rapid progression of the adjacent cranial disc degeneration was observed at the end of the 6 month follow-up period (P = 0.001). CONCLUSION: Modified Pfirrmann grading system revealed that a healthier adjacent intervertebral disc at the caudal level and bi-endplate fracture were significantly associated with an increased risk of delayed union. These findings may influence the management strategy for patients with OVF.

Characterizing the course of back pain after osteoporotic vertebral fracture: a hierarchical cluster analysis of a prospective cohort study.

This study demonstrated four distinct patterns in the course of back pain after osteoporotic vertebral fracture (OVF). Greater angular instability in the first 6 months after the baseline was one factor affecting back pain after OVF. PURPOSE: Understanding the natural course of symptomatic acute OVF is important in deciding the optimal treatment strategy. We used latent class analysis to classify the course of back pain after OVF and identify the risk factors associated with persistent pain. METHODS: This multicenter cohort study included 218 consecutive patients with ≤ 2-week-old OVFs who were enrolled at 11 institutions. Dynamic x-rays and back pain assessment with a visual analog scale (VAS) were obtained at enrollment and at 1-, 3-, and 6-month follow-ups. The VAS scores were used to characterize patient groups, using hierarchical cluster analysis. RESULTS: VAS for 128 patients was used for hierarchical cluster analysis. Analysis yielded four clusters representing different patterns of back pain progression. Cluster 1 patients (50.8%) had stable, mild pain. Cluster 2 patients (21.1%) started with moderate pain and progressed quickly to very low pain. Patients in cluster 3 (10.9%) had moderate pain that initially improved but worsened after 3 months. Cluster 4 patients (17.2%) had persistent severe pain. Patients in cluster 4 showed significant high baseline pain intensity, higher degree of angular instability, and higher number of previous OVFs, and tended to lack regular exercise. In contrast, patients in cluster 2 had significantly lower baseline VAS and less angular instability. CONCLUSIONS: We identified four distinct groups of OVF patients with different patterns of back pain progression. Understanding the course of back pain after OVF may help in its management and contribute to future treatment trials.

New Predictive Index for Lumbar Paraspinal Muscle Degeneration Associated With Aging.

STUDY DESIGN: A cross-sectional imaging study of paraspinal muscle degeneration using a new index for easy evaluation. OBJECTIVE: To examine the natural progression of age-related changes in the lumbar paraspinal muscles and to verify the validity of our new index for evaluating paraspinal muscle degenerationSUMMARY OF BACKGROUND DATA.: Measurement of paraspinal muscle morphology is an effective method for reflecting atrophy and fat infiltration, but it is complicated to perform. Therefore, we focused on the groove between lumbar paraspinal muscles as a simple index for evaluating paraspinal muscle degeneration. METHODS: A total of 160 subjects aged 10 to 88 years (10 male and 10 female subjects in each decade) with lumbar lordosis of more than 20° were included. Body mass index (BMI) was calculated. Sagittal T2-weighted magnetic resonance imaging (MRI) was used to measure lumbar lordosis, while axial T2-weighted MRI was used to measure cross-sectional area (CSA) and fat infiltration rate of the paraspinal muscles at the intervertebral disc level from L1 to L5. To quantify the depth of the groove between the paraspinal muscles, our own image index (lumbar indentation value (LIV): equal to the length of the bulge of the muscle to the attachment of the spinous process), also was measured. We then determined the correlation between LIV and paraspinal muscle degeneration. RESULTS: There were no significant differences in BMI and lumbar lordosis between age groups. CSA of the paraspinal muscles tended to decrease with age, and fat infiltration rate increased with age. There was a negative correlation between CSA and fat infiltration rate at all levels (r = -0.474 to -0.634). LIV decreased significantly with age and strongly correlated with CSA at all levels (r = 0.709-0.789). CONCLUSION: Our new index is a simple and effective parameter for evaluating paraspinal muscle degeneration associated with aging. LEVEL OF EVIDENCE: 4.

Lamina horizontalization and facet tropism as the risk factors for adjacent segment degeneration after PLIF.

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: To clarify associations between both lamina horizontalization and facet tropism and adjacent segment degeneration (ASD). SUMMARY OF BACKGROUND DATA: We have previously reported coexistence of lamina horizontalization and facet tropism adjacent to the cranial fusion segment as risk factors for ASD. METHODS: Subjects comprised 20 patients who underwent additional surgery for ASD after L4/5 posterior lumbar interbody fusion (PLIF) for L4 degenerative spondylolisthesis. Patients who underwent additional surgery for ASD (ASD group) were divided into 2 groups according to the duration until additional surgery: early group (n = 13), additional surgery < or =3 years after primary surgery; and late group (n = 7), additional surgery >3 years after primary surgery. As a control group, 20 age- and sex-matched patients who underwent L4/5 PLIF and could be followed for > or =5 years without ASD were selected. Lamina inclination angle at L3 and facet tropism at L3/4 in each group were measured 3 times by 3 individuals blinded to clinical results. Associations between clinical results and these risk factors and influences of these factors for periods up to the occurrence of ASD were investigated. RESULTS: All ASD was observed in the cranial adjacent segment and the most common condition at additional surgery was spondylolisthesis (n = 15, 75%). Lamina inclination angle was significantly higher in the ASD group than in the control group. ASD was observed in 86% of patients with lamina inclination >130 degrees . In addition, facet tropism was more significant in the early group than in the late and control groups. ASD was observed < or =3 years after primary surgery in all patients with both lamina inclination >130 degrees and facet tropism >10 degrees . CONCLUSION: Preexisting lamina horizontalization at the cranial fusion segment seems to affect ASD, and coexistence of lamina horizontalization and facet tropism seems to accelerate ASD after PLIF.

Repair of cervical esophageal perforation using longus colli muscle flap: a case report of a patient with cervical spinal cord injury.

BACKGROUND CONTEXT: Perforation of the esophagus after anterior cervical spine surgery is a rare, but well-recognized complication. The management of esophageal perforation is controversial, and either nonoperative or operative treatment can be selected. PURPOSE: Several reports have described the use of a sternocleidomastoid muscle flap for esophageal repair. In this case report, we describe a longus colli muscle flap as a substitute for a sternocleidomastoid flap in a patient with an esophageal perforation. STUDY DESIGN: Case report. PATIENT SAMPLE: A 20-year-old man sustained cervical spinal cord injury, on diving and hitting his head against the bottom of a pool. A C6 burst fracture was observed with posterior displacement of a bone fragment into the spinal canal. The patient exhibited complete paralysis below the C8 spinal segment level. METHODS: The patient underwent subtotal corpectomy of the sixth cervical vertebra with the iliac bone graft and augmented posterior spinal fixation (C5-7) with pedicle screws. After the primary operation, the patient showed signs of infection such as throat pain, a high fever, and osteolytic change of the grafted bone by cervical radiograph. A second operation was performed to replace the graft bone using fibula. On the day after the operation, food residue was confirmed in the suction drainage tube, suggesting esophagus perforation. A third operation was immediately performed to confirm and treat esophagus perforation, although apparent esophageal perforation could not be detected at the second operation. Because the erosion around the perforation of the esophageal posterior wall was extensive, a longus colli muscle flap transposition was accordingly performed into the interspace between the esophageal posterior wall and the grafted bone in addition to simple suturing of the perforation. RESULTS: Neither high fever nor pharyngeal pain has recurred at latest follow-up, 5 years after surgery. CONCLUSIONS: To the best of our knowledge, this is the first report concerning the use of a longus colli muscle flap for esophageal perforation after anterior cervical spine surgery.