Factors affecting neurological deficits and intractable back pain in patients with insufficient bone union following osteoporotic vertebral fracture

Does Early Treatment With Teriparatide Prevent the Need for Surgical Intervention in Osteoporotic Vertebral Compression Fractures

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

The primary objective of this study is to evaluate the efficacy of early administration of Teriparatide in preventing the necessity of surgical intervention in individuals with osteoporotic vertebral compression fractures.

METHODS

In a 24-month follow-up retrospective analysis, 191 OVCF patients from January 2016 to October 2020 were randomly assigned to Non teriparatide Group A (n = 104) or Group B teriparatide (n = 87). At baseline, 6 months, 1 year, and 2 years following treatment, demographic data and need of surgical intervention, VAS, ODI, union rates, and kyphosis development, were examined.

RESULTS

Our study found that non-teriparatide group individuals had an 11.53% higher risk of non-union formation that required surgery. Only 8.63% of teriparatide group patients needed surgery. Both groups had significant VAS score reductions. Non-teriparatide group scores declined from 8.38 ± 0.74 to 3.15 ± 1.40, while teriparatide group scores decreased from 8.49 ± 0.73 to 1.11 ± 0.31. The 2-year follow-up ODI scores significantly decreased, with values of 25.02 ± 13.94 for non-teriparatide patients and 15.11 ± 2.17 for teriparatide patients. The kyphosis progression angles in the teriparatide group were considerably lower (4.97 ± 0.78°) compared to the other group (8.09 ± 1.25°).

CONCLUSION

With increasing elderly populations, it is necessary to take measures to prevent surgical intervention in osteoporotic spinal compression fractures. Teriparatide can be employed as an early medication in the management of these fractures to avert non-union and the minimise the progression of kyphosis.

Is Teriparatide Superior in Treating Osteoporotic Vertebral Compression Fractures in Comparison to Bisphosphonates Treatment Alone: A 2-Year Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to compare the efficacy of bisphosphonates and teriparatide in the management of osteoporotic vertebral compression fractures with regard to pain management, prevention of nonunion, and radiological as well as clinical outcomes.

OVERVIEW OF LITERATURE

Osteoporosis refers to a skeletal disorder characterized by decreased bone strength caused by poor bone density and quality causing fragility, resulting in long periods of pain-related immobilization.

METHODS

In a 24-month follow-up retrospective study, 191 patients with osteoporotic vertebral compression fractures were randomly assigned to the bisphosphonate group (n=104) or the teriparatide group (n=87), with patients opting for their treatment between January 2016 and October 2020. Demographic data and patient-reported outcomes scores, including the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), union rates, and kyphosis progression, were assessed at baseline, 6 months, 1 year, and 2 years after treatment.

RESULTS

Both groups had a significant decrease in VAS, from 8.38±0.74 to 3.15±1.40 in the bisphosphonate group and from 8.49±0.73 to 1.11±0.31 in the teriparatide group. The ODI scores reduced significantly at 2-year follow-ups, recording 25.02±13.94 and 15.11±2.17 in the bisphosphonate and teriparatide groups, respectively. Risks of nonunion development were slightly higher at 11.53% in the bisphosphonate group and 8.63% in the teriparatide group required operative intervention. The kyphosis progression angles were also significantly lower in the teriparatide group (4.97°±0.78°) than in the bisphosphonate group (8.09°±1.25°).

CONCLUSIONS

Over time, numerous studies have demonstrated the efficacy of bisphosphonates and teriparatide in ameliorating pain. In this study, the efficacy of teriparatide surpassed that of bisphosphonates in certain aspects, such as the initial 6-month union rates and reduction in the progression of segmental kyphosis. However, bisphosphonates and teriparatide yield similar and favorable union rates at 1 year and final follow-up.

Risk of Revision After Vertebral Augmentation for Osteoporotic Vertebral Fracture: A Narrative Review

Osteoporotic vertebral fractures (OVFs) can hinder physical motor function, daily activities, and the quality of life in elderly patients when treated conservatively. Vertebral augmentation, which includes vertebroplasty and balloon kyphoplasty, is a commonly used procedure for OVFs. However, there have been reports of complications. Although serious complications are rare, there have been instances of adjacent vertebral fractures, cement dislocation, and insufficient pain relief due to cement failure, sometimes necessitating revision surgery. This narrative review discusses the common risks associated with vertebral augmentation for OVFs, such as cement leakage and adjacent vertebral fractures, and highlights the risk of revision surgery. The pooled incidence of revision surgery was 0.04 (0.02-0.06). The risks for revision are reported as follows: female sex, advanced age, diabetes mellitus, cerebrovascular disease, dementia, blindness or low vision, hypertension, hyperlipidemia, split type fracture, large angular motion, and large endplate deficit. Various treatment strategies exist for OVFs, but they remain a subject of controversy. Current literature underscores the lack of substantial evidence to guide treatment strategies based on the risks of vertebral augmentation. In cases with a high risk of failure, other surgeries and conservative treatments should also be considered as treatment options.

Spinal pseudoarthrosis following osteoporotic vertebral fracture: prevalence, risk factors, and influence on patients' activities of daily living 1 year after injury

PURPOSE

To investigate the prevalence and risk factors and influence of pseudoarthrosis on activities of daily living (ADL) of patients with osteoporotic vertebral fracture (OVF).

METHODS

Spinal pseudoarthrosis is defined as the presence of a cleft in the vertebral body on a lateral X-ray image in the sitting position at 1 year after admission. Of the total 684 patients treated for OVF between January 2012 and February 2019 at our institution, 551 patients (mean age, 81.9 years; a male-to-female ratio, 152:399) who could be followed up to 1 year were included in this study. Prevalence, risk factors, and influence of pseudoarthrosis on the ADL of patients as well as fracture type and location were investigated. Pseudoarthrosis was set as the objective variable. Total bone mineral density, skeletal muscle mass index, sex, age, history of osteoporosis treatment, presence of dementia, vertebral kyphosis angle, fracture type (presence of posterior wall injury), degree of independence before admission, history of steroid use, albumin level, renal function, presence of diabetes, and diffuse idiopathic skeletal hyperostosis were set as explanatory variables for multivariate analysis of the influence of pseudoarthrosis on the walking ability and ADL independence before and 1 year after OVF.

RESULTS

In total, 54 (9.8%) patients were diagnosed with pseudarthrosis 1 year after injury (mean age, 81.3 ± 6.5 years; male-to-female ratio, 18:36). BKP was performed in nine patients who did not develop pseudoarthrosis after 1 year. In the multivariate analysis, only the presence of posterior wall injury was significantly correlated with the presence of pseudoarthrosis (OR = 2.059, p = 0.039). No significant difference was found between the pseudarthrosis group and the non-pseudarthrosis group in terms of walking ability and ADL independence at 1 year.

CONCLUSIONS

The prevalence of pseudoarthrosis following OVF was 9.8%, and its risk factor was posterior wall injury. The BKP group was not included in the pseudoarthrosis group, which may have led to an underestimation of the prevalence of pseudoarthrosis. The prevalence, risk factors, and influence of spinal pseudoarthrosis on patients' ADL following osteoporotic vertebral fracture (OVF) were investigated. Pseudoarthrosis occurs in 9.8% 1 year after the injury in patients with OVF. Posterior wall injury was the risk factor of pseudoarthrosis.

Subsequent Domino Osteoporotic Vertebral Fractures Adversely Affect Short-Term Health-Related Quality of Life: A Prospective Multicenter Study

Background and Objectives: Conservative treatment is the gold standard for acute osteoporotic vertebral fractures (AOVFs). However, the treatment strategy for multiple AOVFs remains unknown. We conducted a prospective study using magnetic resonance imaging (MRI) to investigate how rapidly subsequent osteoporotic vertebral fractures (OVFs) occur as domino OVFs within 3 months. This study aimed to assess the incidence and impact of domino OVFs on quality of life (QOL) following conservative treatment for initial AOVFs. Materials and Methods: A prospective multicenter cohort study was conducted at eight hospitals. The included patients were those with AOVFs occurring within 3 weeks, aged >60 years, and diagnosed using MRI. All patients were treated conservatively and underwent MRI after 3 months. Subsequent domino OVFs were defined as newly occurring OVFs within 3 months. Patient characteristics, types of conservative treatment, and patient-reported outcomes, including a visual analogue scale (VAS), the Oswestry disability index (ODI), and the Japanese Orthopaedic Association back pain evaluation questionnaire (JOABPEQ), were evaluated and compared between the domino OVF and non-domino OVF groups. Results: A total of 227 patients were analyzed. The mean age was 80.1 ± 7.3 years and 78% were female. Subsequent domino OVFs were observed in 31 (13.6%) patients within 3 months. An increasing number of prevalent OVFs were significantly associated with domino OVFs (p = 0.01). No significant differences in bone mineral density, type of brace, and anti-osteoporosis medications were found between the two groups. The JOABPEQ (excluding social function), ODI, and VAS were significantly improved after 3 months. Patients with domino OVFs at 3 months had poorer JOABPEQ social life function, ODI, and VAS than those with non-domino OVFs. Conclusions: In this study, the incidence of domino OVFs was 13.6% within 3 months. Domino OVFs had a negative impact on QOL at 3 months and were associated with prevalent OVFs.

Effect of Teriparatide on Subsequent Fracture and Bone Mineral Density in 47 Women with Pregnancy- and Lactation-associated Osteoporosis and Vertebral Fractures

Introduction Pregnancy- and lactation-associated osteoporosis (PLO) with predominantly vertebral fractures is a rare but severe disease which can occur in the last trimester of pregnancy or postpartum. The aim of the present study was to assess the impact of teriparatide on subsequent fractures and bone mineral density (BMD) in patients with PLO.

Materials and Methods A total of 47 patients with PLO and postpartum spinal fractures (mean: 4 fractures) undergoing treatment with teriparatide were investigated. The data collection period was set between 2006 and 2018. All patients received a subcutaneous injection of 20 µg teriparatide once a day for 24 months as well as individually adapted vitamin D supplementation. After 24 months of treatment, all women received no further treatment and either had regular menstrual cycles or took oral contraceptives. Fractures were confirmed by X-ray or MRI. Changes in BMD from baseline were examined using serial DXA measurements.

Results After 24 months of teriparatide treatment, we could demonstrate an increase in BMD at the lumbar spine, femoral neck and total hip of + 30.1%, + 11.7% and + 12.2% respectively (p < 0.001 for all). At 12 months after cessation of treatment, BMD remained stable compared to the 24-month measurements at the lumbar spine, femoral neck and total hip which showed non-significant changes of + 1.4%, + 2.6% and + 4.1% respectively. Out of the 47 patients with PLO with a mean of 4 existing fractures, 4 patients (7.8%) sustained a subsequent fracture, two after 3 – 5 months of treatment and two at > 6 months of treatment.

Conclusion 24 months of treatment with teriparatide in women with PLO and multiple vertebral fractures significantly increased BMD, predominantly BMD of the spine. As patients were premenopausal, there was no significant decrease in BMD in the following 12 months after cessation of treatment.

Osteoporotic vertebral fractures: radiologic diagnosis, clinical and radiologic factors affecting surgical decision making: WFNS Spine Committee Recommendations

With the varied literature on osteoporotic vertebral fracture that may predispose to diagnostic and management dilemma, it is timely to evaluate and streamline the evidence. The aim of this review is to create recommendations on osteoporotic vertebral fractures regarding radiologic diagnosis, and clinical and radiological factors affecting surgical decision making. A computerized literature search was done using PubMed, Google scholar and Cochrane Database of Systematic Reviews from 2010 to 2020. For radiologic diagnosis, the keywords "osteoporotic vertebral fractures" and "radiologic diagnosis" were used yielding 394 articles (19 relevant articles). For clinical and radiological factors affecting surgical decision making, the keywords "osteoporotic vertebral fractures", "radiologic diagnosis", and "surgery" were used yielding 568 articles (25 relevant articles). All pertinent data were reviewed, and consensus statements were obtained in two virtual separate consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine committee. The statements were voted and yielded positive or negative consensus using the Delphi method. This review summarizes the WFNS Spine Committee recommendations on the radiologic diagnosis, and clinical and radiological factors affecting surgical decision making of osteoporotic vertebral fractures.

Osteoporotic Thoracolumbar Vertebral Fractures With Neurological Deficit Treated by Balloon Kyphoplasty Augmented with Newly Developed Minimally Invasive Posterior Hook Stabilization

Most osteoporotic vertebral fractures (OVFs) are treated conservatively, but surgery is often indicated for residual pain, neuropathy, or severe deformity. OVFs tend to develop in elderly patients, so less invasive surgery is desirable. Surgery is mainly performed to stabilize the fractured vertebral body. Percutaneous cement augmentation, such as via balloon kyphoplasty (BKP), has produced satisfactory results as a surgical method for managing OVFs. Posterior fixation with implants is often performed with or without cement augmentation when stronger fixation is considered necessary for OVFs with local kyphosis and angular instability. Pedicle screws (PSs) are widely used as an implant for posterior fixation, but given the risk of backing out in bones with severe osteoporosis, several measures have been taken to increase the strength such as by adding hooks. In cases of osteoporosis, hooks that can use cortical bone as an anchor are considered more useful than PS but are rarely used in minimally invasive surgery. We developed a minimally invasive posterior hook stabilization approach to directly stabilize the posterior spinal components as a new augmentation method for BKP and applied it to four cases of thoracolumbar OVF with neurological symptoms. The operation time was about 60 minutes, including BKP, and the estimated blood loss was about 10 ml. No postoperative implant problems occurred, and in all cases, neurological symptoms, such as buttocks and leg pain, were alleviated at an early stage after surgery. One patient had a postoperative adjacent vertebral body fracture that was conservatively treatable. Minimally invasive posterior hook stabilization, which we developed as a way of augmenting BKP, was considered useful for managing vertebral body fractures of the thoracolumbar spine with local kyphosis and angular instability.

Using artificial intelligence to diagnose fresh osteoporotic vertebral fractures on magnetic resonance images

BACKGROUND CONTEXT

Accurate diagnosis of osteoporotic vertebral fracture (OVF) is important for improving treatment outcomes; however, the gold standard has not been established yet. A deep-learning approach based on convolutional neural network (CNN) has attracted attention in the medical imaging field.

PURPOSE

To construct a CNN to detect fresh OVF on magnetic resonance (MR) images.

STUDY DESIGN/SETTING

Retrospective analysis of MR images PATIENT SAMPLE: This retrospective study included 814 patients with fresh OVF. For CNN training and validation, 1624 slices of T1-weighted MR image were obtained and used.

OUTCOME MEASURE

We plotted the receiver operating characteristic (ROC) curve and calculated the area under the curve (AUC) in order to evaluate the performance of the CNN. Consequently, the sensitivity, specificity, and accuracy of the diagnosis by CNN and that of the two spine surgeons were compared.

METHODS

We constructed an optimal model using ensemble method by combining nine types of CNNs to detect fresh OVFs. Furthermore, two spine surgeons independently evaluated 100 vertebrae, which were randomly extracted from test data.

RESULTS

The ensemble method using VGG16, VGG19, DenseNet201, and ResNet50 was the combination with the highest AUC of ROC curves. The AUC was 0.949. The evaluation metrics of the diagnosis (CNN/surgeon 1/surgeon 2) for 100 vertebrae were as follows: sensitivity: 88.1%/88.1%/100%; specificity: 87.9%/86.2%/65.5%; accuracy: 88.0%/87.0%/80.0%.

CONCLUSIONS

In detecting fresh OVF using MR images, the performance of the CNN was comparable to that of two spine surgeons.

Surgical Outcomes After Minimally Invasive Direct Lateral Corpectomy with Percutaneous Pedicle Screws for Osteoporotic Thoracolumbar Vertebral Collapse with Neurologic Deficits in the Thoracolumbar Spine Compared with Those After Posterior Spinal Fusion with Vertebroplasty

STUDY DESIGN

Retrospective observational study of a cohort of consecutive patients.

OBJECTIVE

The aim of this study was to compare surgical invasion, mechanical complications, and clinical and radiological outcomes 2 years after surgery between minimally invasive corpectomy following percutaneous pedicle screw placements (X-core/PPS) and posterior fixation with vertebroplasty (VP) for treating osteoporotic vertebral fractures (OVFs), which failed conservative treatment due to neurological deficits.

SUMMARY OF BACKGROUND DATA

Numerous studies have proposed surgical procedures to treat OVFs that fail conservative treatment. However, an optimal approach remains controversial because patients often have numerous comorbid medical complications, frequent instrumentation failure, and/or adjacent vertebral fracture (AVF). Recently, a minimally invasive lateral approach has attracted attention as an alternative procedure to the thoracolumbar junction for corpectomy and expandable cage replacement (X-Core Adjustable VBR System). However, its usefulness and validity is largely unknown.

METHODS

A cohort of 102 consecutive patients with OVF at T11-L1 who underwent surgery were followed up for >2 years after surgery. Ultimately 50 patients were included in the VP group and 45 in the X-core/PPS group. Surgical invasion, radiological examinations, and clinical outcomes between two procedures were compared.

RESULTS

Both X-core/PPS and VP procedures were safe and acceptable for neurological improvement and surgical invasion. The correction loss of local kyphotic angle (LKA) and occurrence of AVF were significantly less in the X-core/PPS group. Oswestry Disability Index in the X-core/PPS group at 2 years after surgery showed better recovery than that in the VP group, and no revision surgery was needed in the X-core/PPS group. Postoperative correction loss of LKA increased significantly when intraoperative endplate injury developed.

CONCLUSION

This next-generation minimally invasive anterior and posterior combined surgery was found to be a safe and useful procedure for OVF treatment to reduce correction loss, mechanical complication, and AVF, resulting in less postoperative low back pain.Level of Evidence: 3.

Safety and efficacy of Wharton's jelly-derived mesenchymal stem cells with teriparatide for osteoporotic vertebral fractures: A phase I/IIa study

Osteoporotic vertebral compression fractures (OVCFs) are serious health problems. We conducted a randomized, open-label, phase I/IIa study to determine the feasibility, safety, and effectiveness of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) and teriparatide (parathyroid hormone 1-34) in OVCFs. Twenty subjects with recent OVCFs were randomized to teriparatide (20 μg/day, daily subcutaneous injection for 6 months) treatment alone or combined treatment of WJ-MSCs (intramedullary [4 × 107 cells] injection and intravenous [2 × 108 cells] injection after 1 week) and teriparatide (20 μg/day, daily subcutaneous injection for 6 months). Fourteen subjects (teriparatide alone, n = 7; combined treatment, n = 7) completed follow-up assessment (visual analog scale [VAS], Oswestry Disability Index [ODI], Short Form-36 [SF-36], bone mineral density [BMD], bone turnover measured by osteocalcin and C-terminal telopeptide of type 1 collagen, dual-energy x-ray absorptiometry [DXA], computed tomography [CT]). Our results show that (a) combined treatment with WJ-MSCs and teriparatide is feasible and tolerable for the patients with OVCFs; (b) the mean VAS, ODI, and SF-36 scores significantly improved in the combined treatment group; (c) the level of bone turnover markers were not significantly different between the two groups; (d) BMD T-scores of spine and hip by DXA increased in both control and experimental groups without a statistical difference; and (e) baseline spine CT images and follow-up CT images at 6 and 12 months showed better microarchitecture in the combined treatment group. Our results indicate that combined treatment of WJ-MSCs and teriparatide is feasible and tolerable and has a clinical benefit for fracture healing by promoting bone architecture. Clinical trial registration: https://nedrug.mfds.go.kr/, MFDS: 201600282-30937.

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.

Presence of sarcopenia does not affect the clinical results of balloon kyphoplasty for acute osteoporotic vertebral fracture

Sarcopenia has been associated with poor clinical outcomes in several diseases. Herein, the clinical results of balloon kyphoplasty (BKP) for acute osteoporotic vertebral fracture (OVF) treatment were assessed and compared between sarcopenia and non-sarcopenia patients. Sixty patients who underwent BKP for treatment of acute OVF with poor prognostic factors between April 2016 and September 2017 and were assessed for sarcopenia were enrolled. Clinical results (back pain on visual analogue scale [VAS]; short-form [SF] 36; vertebral deformity; activities of daily living levels; and incidence of adjacent vertebral fractures) were compared between the two groups at 6 months post-BKP. Data analysis revealed that back pain on VAS, SF-36 scores, and vertebral deformity improved from baseline to 6 months after BKP. Thirty-nine patients (65.0%) were diagnosed with sarcopenia and demonstrated a lower body mass index (21.2 vs. 23.3 kg/m², p = 0.02), skeletal muscle mass index (5.32 vs. 6.55 kg/m², p < 0.01), hand-grip strength (14.7 vs. 19.2 kg, p = 0.01), and bone mineral density of the femoral neck (0.57 vs. 0.76 g/cm², p < 0.01) than those of patients without sarcopenia. However, no significant differences were observed in the clinical results between these groups. Therefore, BKP's clinical results for the treatment of acute OVF are not associated with sarcopenia.

A short-segment fusion strategy using a wide-foot-plate expandable cage for vertebral pseudarthrosis after an osteoporotic vertebral fracture

OBJECTIVE

Various surgical treatments have been reported for vertebral pseudarthrosis after osteoporotic vertebral fracture (OVF). However, the outcomes are not always good. The authors now have some experience with combined anterior-posterior short-segment spinal fusion (1 level above and 1 level below the fracture) using a wide-foot-plate expandable cage. Here, they report their surgical outcomes with this procedure.

METHODS

Between June 2016 and August 2018, 16 consecutive patients (4 male and 12 female; mean age 75.1 years) underwent short-segment spinal fusion for vertebral pseudarthrosis or delayed collapse after OVF. The mean observation period was 20.1 months. The level of the fractured vertebra was T12 in 4 patients, L1 in 3, L2 in 4, L3 in 3, and L4 in 2. Clinical outcomes were assessed using the lumbar Japanese Orthopaedic Association (JOA) scale and 100-mm visual analog scale for low-back pain. Local kyphotic angle, intervertebral height, bone union rate, and instrumentation-related adverse events were investigated as imaging outcomes. The data were analyzed using the Wilcoxon signed-rank test.

RESULTS

The mean operating time was 334.3 minutes (range 256-517 minutes), and the mean blood loss was 424.9 ml (range 30-1320 ml). The only perioperative complication was a superficial infection of the posterior wound that was cured by irrigation. The lumbar JOA score and visual analog scale value improved from 11.2 and 58.8 mm preoperatively to 20.6 and 18.6 mm postoperatively, respectively. The mean local kyphotic angle and mean intervertebral height were 22.6° and 28.0 mm, respectively, before surgery, -1.5° and 40.5 mm immediately after surgery, and 7.0° and 37.1 mm at the final observation. Significant improvement was observed in both parameters immediately after surgery and at the final observation when compared with the preoperative values. Intraoperative endplate injury occurred in 8 cases, and progression of cage subsidence of 5 mm or more was observed in 2 of these cases. Proximal junctional kyphosis was observed in 2 cases. There were no cases of screw loosening. No cases required reoperation due to instrument-related adverse events. Bone union was observed in all 14 cases that had CT evaluation.

CONCLUSIONS

This short-segment fusion procedure is relatively minimally invasive, and local reconstruction and bone fusion have been achieved. This procedure is considered to be attempted for the surgical treatment of osteoporotic vertebral pseudarthrosis after OVF.

Changes in magnetic resonance imaging signal intensity in predicting complications during acute phase osteoporotic vertebral fractures

Purpose

To demonstrate prediction of complications in osteoporotic vertebral fractures with magnetic resonance imaging (MRI) changes over time.

Methods

MRI signal intensities in osteoporotic vertebral fractures were investigated according to the interval between onset and imaging as follows: 0-10 days (early), 11-20 days (middle), and 21-30 days (later).

Results

The diffuse low pattern rates were 52%, 84%, and 95% and 20%, 24%, and 52% in the early, middle, and later periods on T1-WI and T2-WI, respectively.

Conclusions

The diffuse low pattern increased with time. The MRI prediction of complications depends on the time phase.

Vertebral mobility is a valuable indicator for predicting and determining bone union in osteoporotic vertebral fractures: a conventional observation study

Background

Conservative treatments for osteoporotic vertebral fractures (OVFs) have not been standardized, and criteria for determining bone union have not been established. To determine bone union, we have adopted a cutoff value of 1.0 mm for vertebral mobility (V-mobility), defined as the difference in anterior vertebral height (Ha) between lateral radiographs taken in weight-bearing and non-weight-bearing positions. The present study aimed to investigate the usefulness of V-mobility for determining bone union and predicting bone union at 6 months after OVF onset.

Methods

The study included 54 acute OVFs from T11 to L3 in 53 patients (12 males, 41 females; mean age 82 years; age range 55–97 years) who were hospitalized at ≤ 3 weeks after OVF onset. Vertebral deformity (V-deformity) and V-mobility were evaluated in accordance with Ha on lateral radiographs taken in the sitting position (SIT), lateral decubitus position (DEC), and supine position (SUP). OVFs showing V-mobility of ≤ 1.0 mm between SIT and DEC radiographs and no intravertebral cleft on DEC radiograph were defined as semi-union, while those showing V-mobility of ≤ 1.0 mm between SIT and SUP radiographs and no intravertebral cleft on SUP radiograph were defined as bone union. We calculated the bone union rates including semi-unions associated with V-mobility cutoff values of 1.0 mm, 1.5 mm, and 2.0 mm and estimated cutoff values for V-mobility at 5 weeks after OVF onset to predict bone union at 6 months after OVF onset.

Results

The cumulative number of bone unions including semi-unions was more influenced by the different V-mobility cutoff values in Ha for determining bone union in the earlier period compared with the later period in the time course of OVF. Receiver-operating characteristic curve analyses revealed that V-mobility cutoff value of 2.1 mm in Ha between SIT and DEC radiographs at 5 weeks after OVF had moderate accuracy for predicting bone union including semi-union at 6 months after OVF. The mean V-deformity value on SIT radiographs did not progress significantly.

Conclusion

V-mobility in the early stage after OVF can predict bone union at 6 months after OVF and is a useful quantitative indicator for determining bone union.

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.

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 ± 25.9 points in the BKP group and 14.5 ± 29.4 points in the control group (P = 0.03). The VAS pain score improved by 43.4 ± 34.4 in the BKP group and 52.2 ± 29.8 in the control group (P = 0.44). The vertebral body wedge angle improved by 5.5 ± 6.2° in the BKP group and -6.3 ± 5.0° in the control group (P < 0.0001). The percent vertebral body height improved by 15.2 ± 19.2% in the BKP group and -20.6 ± 14.2% 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.

Effect of Teriparatide on Subsequent Vertebral Fractures after Instrumented Fusion Surgery for Osteoporotic Vertebral Fractures with Neurological Deficits

STUDY DESIGN

Retrospective case review.

PURPOSE

To assess the incidence and effect of teriparatide (TP) on subsequent vertebral fractures following a long-instrumented fusion surgery for osteoporotic vertebral fractures (OVFs).

OVERVIEW OF LITERATURE

TP treatment may be a useful strategy for patients with OVFs treated with a long-instrumented surgery.

METHODS

Overall, 47 patients who underwent long-instrumented fusion surgery (≥3 levels) for OVFs with neurological deficits between 2010 and 2013 were enrolled. The mean age of the subjects was 76 years; the study population comprised 20 males and 27 females. The mean follow-up duration was 23 months. The average of fused vertebrae was 4.9. TP was used for 19 patients who comprised the TP group. The incidence of subsequent VFs was estimated with Kaplan-Meier analyses and compared between the TP and non-TP groups using the log-rank test. Risk factors were evaluated using a Cox proportional hazards model.

RESULTS

A total of 38% (18/47 cases) of the subjects were identified with subsequent VFs. There were no significant differences in the age, sex, fused levels, presence of prevalent fractures, and correction loss of the two groups. The occurrence of subsequent VFs was lower in the TP group than in the non-TP group (16% vs. 54%, p=0.014). The log-rank test revealed that the TP treatment significantly reduced the risk of subsequent VFs (p=0.048). A Cox proportional hazards model revealed that preoperative TP treatment is only a protective factor of subsequent VFs after instrumented fusion surgery for OVFs (hazard ratio, 0.281; p=0.047).

CONCLUSIONS

In this retrospective study, pre- and postoperative TP treatment significantly reduced the incidence of subsequent VFs after instrumented fusion surgery for OVFs. A prospective randomized study is warranted to determine the efficacy of TP treatments.

Medial Branch Block Versus Vertebroplasty for 1-Level Osteoporotic Vertebral Compression Fracture: 2-Year Retrospective Study

OBJECTIVE

Percutaneous vertebroplasty (VP) and medial branch block (MBB) are used to treat osteoporotic vertebral compression fractures (VCF). We compared the clinical outcomes, radiologic changes, and economic results of MBB with those of VP in treating osteoporotic VCFs.

METHODS

A total of 164 patients with 1-level osteoporotic VCF were reviewed retrospectively. The clinical outcomes were measured with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). To compare economic costs between groups, total hospital costs at the last follow-up day were calculated.

RESULTS

The patients were divided into 2 groups: 72 patients in the conservative group treated by MBB (MBB group) and 92 patients in the group who underwent VP (VP group). The VAS and ODI scores improved significantly within postoperative week 1 in the VP group compared with the MBB group. However, the VAS and ODI scores did not differ between the groups after 1 postoperative year. After 2 years of follow-up, 14 new fractures occurred in the VP group and 3 in the MBB group. The improvement in compression ratio was statistically greater in the VP group than in the MBB group. However, after 2 years the radiologic changes between groups did not differ statistically. After the final follow-up visits, the hospital costs were significantly lower in the MBB group.

CONCLUSIONS

After 2 years of follow-up, VP and MBB both had similar efficacy in terms of pain relief and radiologic changes. MBB was more cost effective than VP. Thus, MBB alone can be a possible alternative to VP in patients with 1-level osteoporotic VCFs.

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.

SPECT-CT versus MRI in localizing active lesions in patients with osteoporotic vertebral compression fractures

OBJECTIVE

This study aimed to evaluate the difference and consistency between single-photon emission computed tomography-computed tomography (SPECT-CT) and MRI in diagnosing osteoporotic vertebral compression fractures (OVCFs) and identifying active lesions.

PATIENTS AND METHODS

All 46 patients underwent SPECT-CT and MRI examinations. The pain vertebral body and pain sites were determined using both MRI and SPECT-CT during percutaneous kyphoplasty (PKP). The differences before and after treatment were assessed using visual analog scale scores and evaluated using a paired t-test. Furthermore, the difference and conformity of SPECT-CT and MRI in diagnosing OVCFs were determined using the McNemar test and the κ-statistic, and by calculating the accuracy index of SPECT-CT diagnosis.

RESULTS

Among all 46 patients, MRI showed 79 segments that fulfilled the diagnostic criteria for fresh OVCFs, whereas SPECT-CT showed 83 segments, and a total of 77 affected vertebral bodies were treated with PKP. Paired t-test evaluation showed that PKP was effective, suggesting that the affected sites were determined accurately (P<0.05). Furthermore, the κ-statistics indicated that these two methods were highly consistent (P<0.05) and the McNemar test indicated that the efficacy of these two diagnostic methods was closely correlated (P>0.05). In different stages of fractures, especially the acute phase, the consistency of SPECT-CT and MRI in the diagnosis of fresh OVCFs was high.

CONCLUSION

SPECT-CT is the preferred method for imaging diagnosis when patients with suspected OVCFs have contraindications to MRI, particularly for patients with acute fractures.

Effect of an intensive conservative therapy with daily teriparatide administration and rehabilitation for osteoporotic delayed vertebral collapse and paralysis

Although patients with osteoporotic delayed vertebral collapse (ODVC) have frequently been treated surgically, the efficacy and limitation of conservative treatment for it have not yet been reported. The purpose of this study was to investigate the effectiveness and limitation of further intensive conservative treatment for patients with ODVC.Patients treated for ODVC from 2011 to 2014 with a follow-up period of more than 1 year were eligible. The fundamental treatment strategy consisted of surgical treatment following intensive conservative treatment with daily teriparatide and rehabilitation for 3 months. We conducted a surgical treatment for patients who could not keep standing position by themselves because of prolonged leg paralysis or intolerable back pain. We performed a logistic regression model in which surgical treatment was set as an objective variable, and other related factors including sex, age, the level of affected vertebrae, the quality of paralysis, changing rate (δ) of spinal canal encroachment, local kyphotic angle, mobility of collapsed vertebrae, EuroQol questionnaires (EQ5D), numerical rating scale (NRS), and Frankel grade as explanatory variables. We also plotted receiver operating curves (ROCs) to investigate the cutoff values of parameters at the baseline.Thirty patients (6 males and 24 females, mean age 76.7 years) were enrolled. Eventually 12 out of 30 patients avoided surgical treatment because their symptoms were improved. Logistic regression showed that δ of local kyphotic angle (odds ratio: 1.072), P = .01), mobility of collapsed vertebrae (1.063, 0.01), EQ5D (0.98, 0.04), and NRS (1.113, 0.01) were significantly correlated with the need for surgical treatments. Among the factors at baseline, only the mobility of collapsed vertebrae showed a significant value of area under a curve (AUC = 0.727, P = .008).The results that 40% of patients with ODVC did not need further surgical treatment after the intensive conservative treatment was of great significance. Patients with greater mobility of collapsed vertebrae might be treated surgically as quickly as possible.

Comparative study of the paraspinal muscles after OVF between the insufficient union and sufficient union using MRI

Background

Identification of poor prognostic factors for OVF is important but has not yet been clearly established. Despite paraspinal muscles could play an important role in the etiology of OVF, what influence time-dependent changes in paraspinal muscles have after OVF, and the impact on conservative treatments for patients who have an OVF remain largely unknown. The purposes of this study were to (1) evaluate time-dependent changes of the paraspinal musculature using MRI after injury in patients with osteoporotic vertebral fractures (OVFs), and (2) compare paraspinal muscles between conservatively treated patients with OVF who have successful union and those failed to conservative treatment.

Methods

A total of 115 consecutive patients who had sustained a recent OVF injury in the thoracolumbar region were assessed for eligibility using medical records and all required data were available from 90 patients who had been followed up for at least 6 months. Patients who needed to undergo surgery and patients who were diagnosed as having insufficient union after 6 months of follow-up were assigned to a group with insufficient union. Lumbar trunk parameters, relative cross-sectional area (rCSA) and proportion of fat infiltration (FI%) were calculated from MRI. To evaluate the time-dependent changes in the paraspinal muscle in patients after OVF injury, correlations between the timing of MRI and rCSA, FI% were determined. To clarify the impact of paraspinal muscles on the outcome of conservative treatments of patients with OVF, we compared rCSA between the groups.

Results

Sixty-five patients were assigned to a group with insufficient union and 25 patients were assigned to a group with successful union. FI% of the multifidus and erector spinae in the group with insufficient union were significantly greater than in the group with union. The timing of MRI in relation to initial injury was significantly correlated with FI% of the multifidus and erector spinae. rCSA of the erector spinae was significantly larger in the group with successful union than in the group with insufficient union.

Conclusions

These findings indicated a time-dependent increase of fatty degeneration of the multifidus and erector muscles, but no change in the rCSA and larger rCSAs of spinal erectors may play a role in successful union in patients with OVF.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2064-0) contains supplementary material, which is available to authorized users.

Bone Regeneration of Osteoporotic Vertebral Body Defects Using Platelet-Rich Plasma and Gelatin β-Tricalcium Phosphate Sponges

The objective of the present study was to investigate the effect of platelet-rich plasma (PRP) combined with gelatin β-tricalcium phosphate (β-TCP) sponge on bone generation in a lumbar vertebral body defect of ovariectomized rat. After creating critical-size defects in the center of the anterior vertebral body, the defects were filled with the following materials: (1) no material (control group), (2) gelatin β-TCP sponge with PRP (PRP sponge group), and (3) gelatin β-TCP sponge with phosphate-buffered saline (PBS sponge group). Microcomputed tomography and histological evaluation were performed immediately after surgery and at 4, 8, and 12 weeks to assess bone regeneration. Biomechanical test was also performed at postoperative week 12. In the PRP sponge group, both imaging and histological examination showed that visible osteogenesis was first induced and additional growth of bone tissue was observed in the transplanted sponge, compared with the PBS sponge group. There was no negative effect of either PRP sponge or PBS sponge transplantation on bone tissue generation around the periphery of the defect. Biomechanical test showed increased stiffness of the affected vertebral bodies in the PRP sponge group. These results indicate that PRP-impregnated gelatin β-TCP sponge is effective for facilitating bone regeneration in lumbar vertebral bone defect under osteoporotic condition. PRP combined with gelatin β-TCP sponges could be potentially useful for developing a new approach to vertebroplasty for osteoporotic vertebral fracture.

Initial hospitalization with rigorous bed rest followed by bracing and rehabilitation as an option of conservative treatment for osteoporotic vertebral fractures in elderly patients: a pilot one arm safety and feasibility study

We assessed the safety and feasibility of a unified conservative treatment protocol for osteoporotic vertebral fractures in the elderly patients with a 24-week follow-up. Our results showed that initial hospitalization with rigorous bed rest followed by a rehabilitation program using a Jewett brace was safe and feasible in managing patients.

PURPOSE

The purpose of this study was to prove the safety and feasibility of a unified conservative treatment protocol, which included initial hospitalization with rigorous bed rest followed by a rehabilitation program with Jewett brace for osteoporotic vertebral fractures (OVFs) in the elderly patients with a 24-week follow-up.

METHODS

Between April 2012 and Mach 2015, one hundred fifty-four patients met the eligibility for this study. Radiological findings at the 3-week, 6~8-week, 24-week assessment were evaluated. Among these, 11 patients underwent early surgery within the first 2 weeks after admission and 19 patients lost follow-up. Therefore, 124 patients were assessed at the final follow-up visit.

RESULTS

The average vertebral instability in all the present series was 4.9 ± 4.8° at 3-week, 2.9 ± 3.5° at 6~8-week, and 1.8 ± 3.0° at 24-week follow-up visit. Delayed union was observed in 16 patients on the 24-week follow-up visit. Therefore, the present conservative treatment protocol resulted in bony union in 98 out of 124 patients (79.0%, per protocol set analysis) and 98 out of 154 patients including drop-out (63.6%, intention-to-treat analysis). There was no severe adverse event related to initial bed rest. The vertebral instability at 3-week assessment was significantly higher in the delayed union group when compared with that in the union group. Univariate analyses followed by multivariate logistic regression analysis revealed that T2-weighted image of confined high intensity on MRI and having more than 5° of vertebral instability on dynamic X-ray at 3-week assessment are the independent risk factors for delayed union of conservative treatment in the present series.

CONCLUSIONS

Our results showed that initial hospitalization with rigorous bed rest followed by a rehabilitation program using a Jewett brace was safe and feasible. Therefore, the present conservative treatment protocol can be one of the acceptable treatment options in managing OVF patients.

Difference of clinical course between cases with bone union and those with delayed union following osteoporotic vertebral fractures

In this prospective multicenter study of osteoporotic vertebral fractures (OVFs), delayed union of OVF at 6-month follow-up caused prolonged pain, QOL impairment, ADL impairment, cognitive status deterioration, and vertebral collapse progression.

PURPOSE

Delayed union following osteoporotic vertebral fracture displayed as an intravertebral cleft on plain X-rays was reported to be a factor for prolonged severe pain. However, the difference of clinical course between bone union and delayed union cases still remains unclear. The purpose of this study was to identify how OVF delayed union following conventional conservative treatment influences the clinical course with a prospective multicenter study.

METHODS

A total of 324 OVF patients from 25 institutes in Osaka, Japan, were included in the study. At the 6-month follow-up after initial visit to each institute, the patients were classified into bone union and delayed union groups based on plain X-ray findings. The outcome assessments included a VAS for back pain, SF-36 for quality of life (QOL), severity of bed-ridden state for activities of daily living (ADL), MMSE for cognitive functions, and degree of vertebral collapse on plain X-rays.

RESULTS

Overall, 280 patients were included into the union group and 44 into the delayed union group. The VAS score at 6 months was significantly worse in the delayed union group (p = 0.01). The scores for the SF-36 scales of physical functioning and bodily pain at 6 months were significantly lower in the delayed union group (p = 0.019, p = 0.01, respectively). The percentage of nearly or completely bed-ridden patients was significantly higher in the delayed union group. The percentage of newly developed cognitive impairment was significantly higher in the delayed union group (p = 0.02). Progression of vertebral collapse during the 6-month follow-up was more pronounced in the delayed union group (p < 0.01).

CONCLUSION

The present results revealed that delayed union following OVF causes prolonged pain, QOL impairment, ADL impairment, cognitive status deterioration, and vertebral collapse progression.

Delayed Neurological Deficits after Osteoporotic Vertebral Fractures: Clinical Outcomes after Surgery

Study Design

Retrospective cohort.

Purpose

To review the clinical presentation of operated patients with delayed neurological deficits after osteoporotic vertebral fractures (OVFs).

Overview of Literature

Delayed neurological deficits can occur from 1 week to 5.7 months after OVFs. Baba has reported 78% good-to-excellent improvement (i.e., ≥50%) after 20 posterior (Cotrel-Dubousset) and 7 anterior (Kaneda in 4, Zielke ventral derotational spondylodesis in 2, and un-instrumented anterior fusion in 1) fusions. Predictive factors for neurological deficits include burst type, vacuum sign, kyphosis, angular instability, and retropulsion.

Methods

Patients with neurological deficits after OVF who received spinal operations between 2000 and 2016 were included.

Results

Totally, 28 patients with a mean age of 77 years underwent surgery. Neurological deficits occurred at an average of 5.4 weeks after the onset of back pain. The most common site was L1. Burst fracture was present in 14 patients and vacuum sign in seven. Surgery was performed within an average of 3.9 days of the onset of neurological deficit. Baba's score improved significantly from 5.96 to 9.81, with good-to-excellent improvement in 18 (64%) patients. Better outcomes based on Baba's scores (improvement>60% [median]) were associated with compression fractures, preoperative retropulsion of <41%, and correction of >16%. Poor improvement in Baba's scores (<25%) was associated with surgical complications and burst fracture type. Twenty-two patients (79%) regained walking ability, and seven of 15 (47%) patients demonstrated improved sphincter control at the latest follow-up. Six Frankel grade B patients did not achieve neurological recovery, four of whom exhibited postoperative surgical complications and died at 2 years because of medical problems. Implant migration occurred in six patients, albeit this was of no clinical significance.

Conclusions

Although OVFs are commonly considered benign, delayed neurological deficits can occur. The significant improvement in clinical function after surgery for neurological deficits is associated with compression (and not burst) fractures, lack of surgical complications, and optimal restoration of retropulsion.

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.

Effect of teriparatide (rh-PTH 1-34) versus bisphosphonate on the healing of osteoporotic vertebral compression fracture: A retrospective comparative study

Background

Teriparatide (recombinant human parathyroid hormone 1–34) is increasingly used for the treatment of severe osteoporosis because it stimulates bone formation and may potentially enhance fracture healing. The objective of this study was to investigate the effects of teriparatide versus a bisphosphonate on radiographic outcomes in the treatment of osteoporotic vertebral compression fractures (OVCF).

Methods

A total of 98 patients undergoing non-operative treatment for recent single-level OVCF were reviewed retrospectively. Thirty-eight patients were treated by a once-daily subcutaneous injection of 20 micrograms of teriparatide (TPD group), whereas 60 patients received 35 mg of alendronate weekly (BP group). Except for these medications, the same treatment protocol was applied to both groups. The radiographic assessments included union status, vertebral kyphosis, and mid-vertebral body height. The rates of fracture site surgical intervention were also compared between the two groups. The mean follow-up period was 27 months (median 22.5, range 2 – 75 months).

Results

Cox regression analysis showed that TPD reduced the time-to-union (adjusted relative hazard ratio: 1.86, 95% C.I.: 1.21 – 2.83). The union rate at six months after treatment was 89% in the TPD group and 68% in the BP group; the surgical intervention rate was significantly higher in the TPD group (p = 0.026, adjusted odds ratio: 8.15, 95% C.I.: 2.02 – 43.33). The change in local kyphosis was 4.6° in the TPD group and 3.8° in the BP group (p = 0.495, paired t-test). The change of mid-vertebral body height was 4.4 mm in the TPD group and 3.4 mm in the BP group (p = 0.228, paired t-test). Fracture site surgical interventions were not required in the TPD group; however, two patients in the BP group eventually underwent surgical treatment for symptomatic non-union or vertebral collapse.

Conclusions

This retrospective study suggests that teriparatide may enhance fracture healing and improve the union rate in OVCF.

Relationship between clinical symptoms of osteoporotic vertebral fracture with intravertebral cleft and radiographic findings

BACKGROUND

With aging of the population, the numbers of osteoporotic vertebral fractures with intravertebral cleft have been increasing. However, the details of clinical symptoms of osteoporotic vertebral fractures with intravertebral cleft are poorly understood. The purpose of this study was to evaluate the relationship between clinical symptoms of osteoporotic vertebral fractures with intravertebral cleft and radiographic findings.

METHODS

Two hundred seventeen patients with single-level osteoporotic vertebral fractures with intravertebral cleft were examined. Clinical symptoms were evaluated using Numerical Rating Scale for back pain and the Oswestry Disability Index for physical disability. The presence of delayed neurologic deficit was also detected. Radiography and computed tomography were used to measure local kyphotic angle and vertebral instability and to detect the presence of posterior wall fracture of the vertebral body. Correlations between clinical symptoms of osteoporotic vertebral fractures with intravertebral cleft and radiographic findings were investigated.

RESULTS

Mean Numerical Rating Scale and Oswestry Disability Index were 7.4 and 58.0%, respectively. Delayed neurologic deficit occurred in 41 patients (19%). The mean local kyphotic angle, vertebral instability, and rate of posterior wall fracture of the vertebral body were 19.4°, 7.3°, and 91%, respectively. Numerical Rating Scale and Oswestry Disability Index were statistically correlated with vertebral instability but not with local kyphotic angle and presence of posterior wall fracture. In the patients with delayed neurologic deficit, vertebral instability was significantly higher and posterior wall fractures were significantly more frequent than in the patients without delayed neurologic deficit. Local kyphotic angle was not correlated with delayed neurologic deficit.

CONCLUSIONS

Vertebral instability is a factor causing symptoms of osteoporotic vertebral fractures with intravertebral cleft. In addition, vertebral instability may be the predominant cause of delayed neurologic deficit. To manage osteoporotic vertebral fractures with intravertebral cleft and delayed neurologic deficit efficiently, it may be important to control vertebral instability of osteoporotic vertebral fractures.

Predicting delayed union in osteoporotic vertebral fractures with consecutive magnetic resonance imaging in the acute phase: a multicenter cohort study

This study demonstrated the predictive values of radiological findings for delayed union after osteoporotic vertebral fractures (OVFs). High-signal changes on T2WI were useful findings.

INTRODUCTION

The purpose of the present study is to determine predictive radiological findings for delayed union by magnetic resonance imaging (MRI) and plain X-rays at two time points in the acute phase of OVFs.

METHODS

This multicenter cohort study was performed from 2012 to 2015. A total of 218 consecutive patients with OVFs ≤2 weeks old were enrolled. MRIs and plain X-rays were performed at the time of enrollment and at 1- and 6-month follow-ups. Signal changes on T1-weighted imaging (T1WI) were classified as diffuse low-, confined low-, or no-signal change; those on T2WI were classified as high (similar to the intensity of cerebrospinal fluid), confined low-, diffuse low-, or no-signal change. The angular motion of the fractured vertebral body was measured with X-rays.

RESULTS

A total of 153 patients completed the 6-month follow-up. A high-signal change on T2WI was most useful in predicting delayed union. Sensitivity, specificity, and positive predictive values were 53.3, 87.8, and 51.6 % at enrollment and 65.5, 84.8, and 51.4 % at the 1-month follow-up, respectively. The positive predictive value increased to 62.5 % with observation of high- or diffuse low-signal changes at both enrollment and the 1-month follow-up. The cutoff value of vertebral motion was 5 degrees. Sensitivity and specificity at enrollment were 52.4 and 74.1 %, respectively.

CONCLUSIONS

This study demonstrated the radiological factors predicting delayed union after an OVF. T2 high-signal changes showed the strongest association with delayed union. Consecutive MRIs were particularly useful as a differential tool to predict delayed union following OVFs.

Indication for Partial Vertebral Osteotomy and Realignment in Posterior Spinal Fixation for Osteoporotic Thoracolumbar Vertebral Collapse with Neurological Deficits

Instrumented spinal fixation is ordinarily required in patients who present with myelopathy or cauda equina syndrome secondary to vertebral collapse following osteoporotic thoracolumbar fracture. Posterior spinal fixation is a major surgical option, and partial vertebral osteotomy (PVO) through a posterior approach is occasionally reasonable for achievement of complete neural decompression and improvement of excessive local kyphosis. However, the indications and need for PVO remain unclear. The objectives of this retrospective study were to determine the efficacy and safety of posterior spinal fixation with or without PVO for osteoporotic thoracolumbar vertebral collapse and identify patients who require neural decompression and alignment correction by PVO. We retrospectively reviewed the clinical records of 20 patients (13 females, 7 males; mean age, 67.1 years) who underwent instrumented posterior fixation for osteoporotic thoracolumbar vertebral fracture. Clinical outcomes were assessed by the Japanese Orthopedic Association score and visual analog scale scores in the lumbar and leg areas. PVO was added with posterior spinal fixation in eight patients because neural decompression was incomplete after laminectomy as indicated by intraoperative echo imaging. Neurological and functional recovery significantly improved during follow-up. Clinical outcomes in patients who underwent PVO were similar to those in patients who did not undergo PVO. However, correction of the local kyphotic angle and improvement of spinal canal compromise after surgery was significant in patients who underwent PVO. The patients who required PVO had a less local kyphotic angle in the supine position and higher occupation rate of the fractured fragment in the spinal canal in the preoperative examination.

Therapeutic effects of PKP on chronic painful osteoporotic vertebral compression fractures with or without intravertebral cleft

This study aims to investigate clinical effects of protruding after percutaneous vertebral plasty (PKP holds) for treatment of chronic painful osteoporotic vertebral compression fractures (CPOVCFs), and assess its safety and effectiveness. One hundred and eighteen CPOVCFs patients were included, and analyzed and followed up therapeutic effects of PKP holds. All of these patients were divided into NIVC (73 cases) and IVC (45 cases) group. Comparing operation time, bone cement perfusion, pain intensity modulus visual grading scoring, Oswestry disability index, fracture fanterior relative height, local convex Angle, and surgical complications between the two groups. There were no significant differences between two groups for operation time of PKP holds (P>0.05). Amount of bone cement injection in IVC groups was significantly higher compared to NIVC group (P<0.05). Pain intensity visual modulus ratings and Oswestry disability index were significantly improved in both groups after surgery and postoperative follow-up period compared to pre-operation (P<0.05). Fracture fanterior margin relative height and local convex angle were also significantly improved (P<0.05). Fracture fanterior margin relative height was also significantly improved for IVC compared to NIVC group (P<0.05). There were no differences for bone cement leakage rate and adjacent segment fracture between two groups (P>0.05). But there was a case of bone cement loose, which needs to be treated for further step. In conclusion, PKP holds is a kind of effective and safe method for the IVC and NIVC patients. Especially for the IVC patients, PKP holds can significantly improve the fracture fanterior margin relative height.

Efficacy of Percutaneous Vertebroplasty in the Treatment of Osteoporotic Vertebral Compression Fractures with Intravertebral Cleft

Intravertebral cleft (IVC) is frequently observed in patients with painful osteoporotic vertebral compression fracture (OVCF). Some studies reported the usefulness of percutaneous vertebroplasty (PVP) for treating OVCF with IVC. However, systematic studies are scarce, and their results are conflicting. The purpose of this study was to evaluate the clinical and radiographic results of PVP in the treatment of painful OVCF with IVC. Two hundred ninety-one patients with OVCF with IVC underwent PVP. Back pain was measured using a visual analog scale (VAS), and physical disability was assessed using the Oswestry Disability Index (ODI). Three radiological parameters were assessed: the local kyphotic angle, percentage spinal canal cross-sectional area of compromise, and intravertebral instability of the affected vertebra. The mean follow-up period was 28 months. The mean values for the VAS and ODI were 8.4 and 60.0%, respectively, before PVP, versus 3.9 and 35.4%, respectively, at the final follow-up. The average local kyphotic angle, percentage spinal canal cross-sectional area of compromise, and intravertebral instability were 10.5°, 17.9% and 6.1°, respectively, before PVP and 8.1°, 15.2%, and 0.8°, respectively, at the final follow-up. There were no neurological or systemic complications due to cement leakage. PVP is an effective and safe intervention for treating OVCF with IVC.

Comparative study of 2 surgical procedures for osteoporotic delayed vertebral collapse: anterior and posterior combined surgery versus posterior spinal fusion with vertebroplasty

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse.

SUMMARY OF BACKGROUND DATA

The optimal treatment of osteoporotic delayed vertebral collapse has been controversial. Because of aged patients' numerous comorbid medical complications and frequent instrumentation failure secondary to osteoporosis, it is challenging for surgeons to manage osteoporotic delayed vertebral collapse. In spite of this, there have been few reports comparing the surgical results.

METHODS

A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled at 6 hospitals. Sixty-five patients underwent AP surgery in 3 hospitals, and 28 patients underwent VP surgery in the other 3 hospitals. We restricted the spinal-fracture level to thoracolumbar lesion (T10-L2) and excluded patients followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, disease duration, or duration of follow-up.

RESULTS

Operative time was significantly longer and intraoperative blood loss significantly greater in the AP group. No significant difference between the 2 groups was observed in neurological improvement or the angle of kyphosis correction. However, the loss of correction was significantly greater in the VP group. There were no significant differences in perioperative respiratory or other complications. Implant-related complications and pseudarthrosis were more often observed in the VP group. One patient in the VP group underwent additional surgery for progression kyphosis.

CONCLUSION

AP surgery provides stable spinal fixation and reduces implant failure particularly at the thoracolumbar junction because of load bearing of anterior spinal elements. Surgery-related complications in AP surgery were as few in number as with the VP group, and AP surgery is useful for osteoporotic delayed vertebral fracture.

Discriminating imaging findings of acute osteoporotic vertebral fracture: a prospective multicenter cohort study

Background

Appropriate treatment of osteoporotic vertebral fractures (OVF) requires knowledge of the age of the fracture. Although diagnostic imaging has made remarkable progress in recent years, it remains difficult to differentiate acute fractures from old. Our purpose was to investigate chronological changes in radiological findings after OVF and to identify discriminators of acute versus older injuries.

Methods

We evaluated 139 vertebrae in 136 patients. All patients underwent X-ray and magnetic resonance imaging (MRI) examination within 2 weeks of injury and again after 6 months. The anterior vertebral height ratio (AVHR) was calculated on lateral X-ray, and the intensity change of the posterior wall of the fractured vertebra was evaluated on T1-weighted MRI. The cutoff AVHR value to diagnose acute fracture was determined by receiver operating characteristic (ROC) curve analysis.

Results

Average AVHR fell from 84.6% at initial visit to 63.7% at 6 months. When acute fracture was defined as AVHR >75%, sensitivity was 85.6%, specificity was 67.6%, and positive predictive value was 72.6%. On MRI, 83.5% of fractured vertebrae showed intensity change in the posterior wall in the acute stage, which fell to 41.7% of vertebrae after 6 months. When intensity change in the posterior wall and AVHR >75% were both present, the specificity and positive predictive value for diagnosing acute fracture improved to 87.1% and 84.7%, respectively.

Conclusions

This study suggests that vertebral fracture rarely shows significant collapse on X-ray in the first 2 weeks after injury. The combination of intensity change in the posterior wall on MRI and AVHR >75% on X-ray indicates a high probability of acute fracture.

Surgical treatment for osteoporotic vertebral collapse with neurological deficits: retrospective comparative study of three procedures--anterior surgery versus posterior spinal shorting osteotomy versus posterior spinal fusion using vertebroplasty

PURPOSE

In general, osteoporotic vertebral collapse (OVC) with neurological deficits requires sufficient decompression of neural tissues to restore function level in activities of daily living (ADL). However, it remains unclear as to which procedure provides better neurological recovery. The primary purpose of this study was to compare neurological recovery among three typical procedures for OVC with neurological deficits. Secondary purpose was to compare postoperative ADL function.

METHODS

We retrospectively reviewed data for 88 patients (29 men and 59 women) with OVC and neurological deficits who underwent surgery. Three typical kinds of surgical procedures with different decompression methods were used: (1) anterior direct neural decompression and reconstruction (AR group: 27 patients), (2) posterior spinal shorting osteotomy with direct neural decompression (PS group: 36 patients), and (3) posterior indirect neural decompression and short-segment spinal fusion combined with vertebroplasty (VP group: 25 patients). We examined clinical results regarding neurological deficits and function level in ADL and radiological results.

RESULTS

The mean improvement rates for neurological deficits and ADL function level were 60.1 and 55.0%, respectively. There were no significant differences among three groups in improvement rates for neurological deficits or ADL function level. The VP group had a significantly lower estimated mean blood loss (338 mL) and mean duration of surgery (229 min) than both the AR and PS groups (p < 0.001).

CONCLUSION

Direct neural decompression is not always necessary, and the majority of patients can be treated with a less-invasive procedure such as short-segment posterior spinal fusion with indirect decompression combined with vertebroplasty. The high-priority issue is careful evaluation of patients' general health and osteoporosis severity, so that the surgeon can choose the procedure best suited for each patient.

Risk factors affecting progressive collapse of acute osteoporotic spinal fractures

We prospectively investigated related clinical and radiological risk factors for progression following acute osteoporotic spinal fractures. Fracture location, morphological feature (mid-portion), and involvement of vertebral posterior wall were statistical significant risk factors considering increase of height loss and kyphotic angle, and occurrence of intravertebral cleft sign as a progressive collapse.

INTRODUCTION

This study was designed to investigate the clinical and radiological risk factors related to progressive collapse of acute osteoporotic spinal fractures (OSF).

METHODS

In total, 100 patients with acute OSF were prospectively enrolled at a single institute. Five pathological fractures were excluded. Twelve patients dropped out of the study because of conversion to surgical treatment during follow-up. Eight patients were excluded as follow-up losses. Thus, 75 patients were analyzed. Clinical data and radiological data were recorded and analyzed. As a definition of progressive OSF, height loss≥15%, kyphotic angle≥10°, and the occurrence of an intravertebral cleft sign at the 6-month follow-up compared to the initial values were adopted. Correlation analysis and multiple logistic regression analyses were performed to elucidate the related clinical or radiological factors for progressive OSF.

RESULTS

The occurrence of intravertebral cleft was not related to any significant differences in the clinical results and was only related to the fracture level in the regression analysis. A ≥15% increase in height loss and a ≥10° increase in kyphotic angle were related to worse clinical results. Mid-portion type fractures and involvement of the posterior wall were significant risk factors with relatively high odds ratios for progressive OSF under these criteria.

CONCLUSION

A thoracolumbar fracture, a mid-portion type fracture, and involvement of the vertebral posterior wall are relative risk factors for progressive collapse following acute OSF. More attention should be paid to patients with OSF and these risk factors during conservative management.

A therapeutic efficacy of the transpedicular intracorporeal bone graft with short-segmental posterior instrumentation in osteonecrosis of vertebral body: a minimum 5-year follow-up study

STUDY DESIGN

A retrospective review of clinical and radiological parameters.

OBJECTIVE

The purpose of this study was to investigate the therapeutic efficacy of transpedicular intracorporeal bone graft (IBG) in osteonecrosis of vertebral body (ONV) for 5-years follow-up period.

SUMMARY OF BACKGROUND DATA

Although a broad spectrum of surgical options has been described for the treatment of ONV without neurological deficits, no effective treatment has been definitely established. Limited previous work has reported favorable outcomes with IBG; however, these studies were limited by short-term follow-up and small sample sizes. This study is the first to report the clinical and radiological results of IBG with short-segmental posterior instrumentation in ONV with a 5-year follow-up period.

METHODS

Thirty-six patients were followed for at least 5 years after transpedicular IBG with short-segmental posterior instrumentation. We retrospectively reviewed outcomes, including visual analogue scale score, the Oswestry Disability Index score, compression ratio, and kyphotic angle.

RESULTS

There were 11 complications, including pneumonia in 4 patients, screw loosening in 5 patients, mild hematoma at the subcutaneous tissue in 1 case, and pseudarthrosis in 1 case. The mean visual analogue scale score was exhibiting V-shaped upward trend after postoperative 6 months that ended with the almost similar score obtained with preoperative status. The mean Oswestry Disability Index score was also shown with similar trend. In functional score, there was a statistical significant improvement until only 6 months after surgery. In radiological evaluation, the mean kyphotic angle and compression ratio was significantly corrected after surgery (P < 0.05). However, these improved radiological parameters were maximal at the immediate postoperative time with gradual loss over time.

CONCLUSION

Transpedicular IBG with short-segmental posterior instrumentation may lead to complications such as prolonged back pain and recurrence of kyphotic deformity in the 5 years after the procedure. Therefore, we do not recommend short-segmental posterior instrumentation concurrently with transpedicular IBG for treating ONV.

LEVEL OF EVIDENCE

4.

Augmentation of transpedicular screws by intraoperative vertebroplasty

BACKGROUND AND PURPOSE

The aim of the study was to determine the efficacy of posterior spinal stabilization, combined with intraoperative vertebroplasty defined as intraoperative filling of instrumented vertebral bodies (VB) with polymethylmethacrylate (PMMA).

MATERIAL AND METHODS

Seventeen patients with osteoporosis or osteopenia underwent posterior spinal fusions. The surgical procedures included laminectomy, spondylodesis, insertion of pedicular screws, intraoperative vertebroplasty and correction of spinal deformity.

RESULTS

Postoperative assessment showed improvement of pain in all cases. Motor deficit regressed in 2 of 3 afflicted patients. In 12 vertebrae (27.3%), the mass of PMMA ex-tended from one endplate to another, filling 100% of VB height, in 7 (15.9%) it filled 90-99%, in 14 (31.8%) 80-89%, in 9 (20.4%) 70-79%, and in 2 (4.5%) it filled 50-60% of VB height. In the horizontal plane, PMMA filled central parts of 72.7% of vertebral bodies. PMMA completely surrounded 68.9% of screws, and partially surrounded 18.4% of screws, whereas 12.6% of screws had no contact with cement mass. Spinal stabilization reduced kyphotic deformity in 15 patients (range of reduction: 6°-25°; mean: 13.6°). During follow-up (3-32 months; mean: 16) implants of 11 patients were stable, 1 implant instability was diagnosed 7 months after surgery, 5 patients were lost to follow-up. Asymptomatic cement leaks occurred in 45% of vertebrae.

CONCLUSIONS

Intraoperative vertebroplasty performed after insertion of pedicular screws may be considered as a technical variation useful to stabilize osteoporotic spines. After PMMA hardening, intraoperative manoeuvres to correct spinal deformity were possible without any damage of instrumented vertebrae.

Comparison of the amounts of canal encroachment between semisitting and supine position of computed tomography-myelography for vertebral fractures of the elderly involving the posterior vertebral wall

STUDY DESIGN

A prospective radiographical trial.

OBJECTIVE

To elucidate effects of loading associated with spinal canal encroachment (SCE) in patients with insufficient bone union after vertebral fractures in the elderly, using computed tomography-myelography in 2 different positions.

SUMMARY OF BACKGROUND DATA

In elderly patients with vertebral fractures, influence of loading would be involved in SCE, but the details are not well understood.

METHODS

Seventeen patients (mean age, 77.4 ± 8 yr; range, 62-91 yr) with various degrees of neurological deficit due to insufficient bone union at both vertebral body and posterior vertebral wall were included in this study. Computed tomography-myelography was performed in both semisitting and supine positions. Kyphotic angle, rate of dural compression, ratio of occupation by bony fragments, and posterior vertebral body height ratio were measured and compared between positions.

RESULTS

Mean ratio of occupation by bony fragments was significantly higher in the semisitting position (47.9 ± 9.2%) than in the supine position (33.9 ± 10.0%, P, 0.001). Similarly, mean posterior vertebral body height ratio was significantly lower in the semisitting position (67.8 ± 10.8%) than in the supine position (76.3 ± 13.3%), indicating a significant loss of vertebral height in the semisitting position (P, 0.001). Mean rate of dural compression was likewise significantly higher in the semisitting position (48.6 ± 13.3%) than in the supine position (33.3 ± 16.5%; P, 0.001). Mean change in ratio of occupation by bony fragments, change in posterior vertebral body height ratio, and angular instability between positions were 13.9 ± 8.6%, 8.5 ± 6.7%, and 13° ± 5.7°, respectively. A significant correlation was identified between change in ratio of occupation by bony fragments and change in posterior vertebral body height ratio (P = 0.001).

CONCLUSION

Our study demonstrated that collapse of the nonunited posterior vertebral wall and intracanal protrusion of vertebral fragments would occur simultaneously with axial loading, causing SCE. Computed tomographic scan obtained in semisitting position seems quite useful to evaluate the amount of SCE by an unstable posterior wall.