Osteoporotic vertebral fractures and collapse with intravertebral vacuum sign (Kümmel's disease)

Which vacuum phenomenon is more predictive for future junctional disorders?: Intradiscal or Intrafacet?

Recent spine studies focused on identifying whether intradiscal vacuum phenomenon (VP) was associated with spinal instability. However, none of them reported a direct association between VP and spinal instability following fusion for degenerative lumbar spine disorders (DSDs), namely junctional disorders. In the present study, we aimed to evaluate whether the VP was predictive for junctional disorders in patients who underwent short-segment lumbar decompression and fusion for DSDs at a tertiary spine center. We retrospectively reviewed prospectively collected database of patients who underwent short-segment decompression and fusion for DSDs. Pre-operative sagittal and axial computed tomography (CT) scans were evaluated in terms of intradiscal and intrafacet VP at all lumbar levels, respectively. Each VP was scored as 1 point. Then, the total VP score was calculated as the sum of intradiscal VP score and intrafacet VP score. Then, we analyzed the possible predictivity of VP for junctional disorders at final follow-ups of the patients operated for short-segment lumbar decompression and fusion. Patients with junctional disorders had significantly higher total and intrafacet VP scores compared to those without junctional disorders. Total VP score had an OR of 1.217 (p = 0.014) and intrafacet VP score had an OR of 1.465 (p = 0.008). The ROC analysis depicted that the cut-offs value for total and intrafacet VP scores to predict junctional disorders following short-segment lumbar decompression and fusion were 1.5 points and 0.5 point, respectively. Vacuum phenomenon could be associated with junctional disorders in patients who underwent short-segment lumbar decompression and fusion for DSD. Intrafacet VP was more important than intradiscal VP in predicting junctional disorders. Proper surgical planning including the evaluation of both intrafacet and intradiscal VP at all lumbar levels is crucial to decrease the likelihood of junctional disorders.

Global trends and frontiers of research on Kümmell's disease: A bibliometric analysis

The prevalence of Kümmell's disease (KD) has been increasing due to the aging population and the rise of osteoporotic vertebral compressibility fractures. As a result, there has been a growing concern about this condition. Despite the rapid advancements in its related research fields, the current research status and hotspot analysis of KD remain unclear. Therefore, our goal was to identify and analyze the global research trends on KD using bibliometric tools. All KD data were obtained from the Web of Science Core Collection. The information of research field was collected, including title, author, institutions, journals, countries, references, total citations, and years of publication for further analysis. From 1900 to 2022, a total of 195 articles and 1973 references have been published in this field, originating from 27 countries/regions and 90 journals, with China leading the contributions. The most significant institutional and author contributions come from Soochow University and Kim, HS, respectively. The journal with the highest number of published research and total citation frequency is Spine. The latest research focuses in this field include "risk factor," "osteoporotic vertebral compression fracture," "pedicle screw fixation," "percutaneous vertebroplasty," and "bone cement," and should be closely monitored. Additionally, we have conducted a comprehensive analysis of the 50 most-cited articles in KD, providing a valuable list of articles to guide clinical decision-making and future research for clinicians and researchers. In recent years, there has been a significant increase in scientific research on KD. Future research in KD is likely to focus on surgical treatment, risk factors, and complications.

Efficacy and Safety of High-Viscosity Bone Cement in Percutaneous Vertebroplasty for Kummell's Disease

Background

To analyze and evaluate the clinical outcomes of using high-viscosity bone cement compared to low-viscosity bone cement in percutaneous vertebroplasty (PVP) for treatment of Kummell's disease.

Methods

From July 2017 to July 2019, 68 Kummell's disease patients who underwent PVP were chosen and separated into 2 groups: H group (n = 34), were treated with high-viscosity bone cement and L group (n = 34), treated with low-viscosity bone cement during treatment. The operation time, number of fluoroscopy tests done, and amount of bone cement perfusion were recorded for both groups. Clinical outcomes were compared, by measuring their Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Kyphosis Cobb's angle, vertebral height compression rate, and other complications.

Results

High-viscosity group showed less operation time and reduced number of fluoroscopy tests than the low-viscosity group (P < 0.05). When compared to preoperative period, both groups' VAS and ODI scores were significantly reduced at 1 day and 1 year postoperatively (P < 0.05). The vertebral height compression rate and Cobb's angle were significantly lower (P < 0.05) in both groups after surgery compared with those before surgery (P < 0.05). The cement leakage rate in group H was 26.5%, which was significantly lower than that in group L, which was 61.8% (P < 0.05).

Conclusions

High-viscosity and low-viscosity bone cement in PVP have similar clinical efficacy in reducing pain in patients during the treatment, but in contrast, high-viscosity bone cement shortens the operative time, reduces number of fluoroscopy views and vertebral cement leakage and improves surgical safety.

Correlation analysis between morphologic characteristics of the thoracolumbar basivertebral foramen and Kummell's disease in patients with osteoporosis using imaging techniques

BACKGROUND

The aging of the population is a social problem faced by many countries in the world. With the increase in the elderly population, the number of patients with Kummell's disease is also gradually increasing. No study has demonstrated that Kummell's disease has a clear correlation with the foramen of a vertebrobasilar vein.

OBJECTIVES

The research was conducted to describe and evaluate the morphological characteristics of a basivertebral foramen in patients with osteoporosis and Kummell's disease by CT; to infer whether the specific morphological characteristics of basivertebral foramen may be one of the risk factors of Kummell's disease; to provide clinical suggestions for the treatment of Kummell's disease.

DESIGN

Retrospective analysis from January 2020 to December 2021 on 83 patients with 83 vertebral bodies (T8-L5) diagnosed with senile osteoporosis and Kummell's disease hospitalized in our hospital due to chronic low back pain, including 57 women and 23 men. Group A was assigned for the following patients: the age ranged from 59 to 86 years old, with the average age of 67.30 ± 7.32 years old; the body mass index ranged from 20.01 to 29.46 kg/m², with the average body mass index of 23.51 ± 3.03 kg/m².Group B was assigned for the following patients: 83 patients diagnosed with senile osteoporosis in our outpatient department from January 2020 to December 2021, including 41 males and 42 females; the age ranged from 60 to 85 years, with an average age of 68.52 ± 4.68 years old; the height to weight ratio met the normal reference standard (except 20% above or 10% below the standard weight). Through the lanwon PACS imaging system, the related parameters of the vertebrobasilar foramen in patients with osteoporosis and Kummell's disease were measured to evaluate and analyze the correlation between the morphological characteristics of the vertebrobasilar foramen in patients with osteoporosis and Kummell's disease.

RESULTS

In patients with osteoporosis, the distribution of incidence rate of Kummell's disease in the spine was consistent with that of osteoporotic compression fractures. Sagittal view of the vertebral body on CT scan and the triangular-shaped, trapezoidal-shaped, and irregular-shaped basivertebral foramen in group A accounted for 18%,57%,and 36%,respectively. In group B, triangular-shaped, trapezoidal-shaped, and irregular-shaped foramen accounted for 51%,17%,and 26%,respectively.The distribution of triangular-shaped, trapezoidal-shaped, and irregular-shaped foramen was compared between groups A and B, and the difference was recorded as statistically significant (P < 0.05). Additionally, the difference in the distribution of triangular-shaped, trapezoidal-shaped, and irregular-shaped foramen in group A was found statistically significant (P < 0.05),while that of Group B was found statistically insignificant (P > 0.05).On a horizontal CT scan of the vertebra of group A, triangles, trapezoids, and irregularities accounted for 28%, 26%, and 47%, respectively. In group B, triangles,trapezoids,and irregularities accounted for 31%, 37%, and 30%, respectively. The difference in the distribution of the triangular-shaped and trapezoidal-shaped foramen in groups A and B was statistically insignificant (P > 0.05), while that of irregular-shaped was statistically significant (P < 0.05). Additionally, there was no statistical significance (P > 0.05) in the difference in the morphological distribution of triangular-shaped and trapezoidal-shaped foramen in group A, while that of irregular-shaped was found to be statistically significant (P < 0.05). Further, the difference in the morphological distribution of triangular-shaped, trapezoidal-shaped, and irregular-shaped foramen in group B was not statistically significant (P > 0.05).In general, about 8% of the vertebral body of BF has an osseous septum. In group A, 97% are single-holed while the remaining 3% are porous; in group B, those with single holes accounted for 76%, while the remaining 24% are porous. In groups A and B, the difference in the morphological distribution of single-holed and multi-holed T8, T11, T12, L1, L2, L4, and L5 vertebral bodies was statistically significant (P < 0.05). In group A, the difference in the distribution of single-holed and multi-holed L1 and L5 vertebral bodies was statistically significant (P < 0.05). Similarly, the difference in the distribution of single-holed and multi-holed T8, T11, T12, L1, L2, and L4 basivertebral foramen was statistically significant (P < 0.05).

CONCLUSIONS

In patients with osteoporosis, the incidence of vertebral Kummell's disease can be associated with the morphological characteristics of the basivertebral foramen, as observed in the CT scan. Furthermore, the vertebral body with trapezoidal-shaped and irregular-shaped basivertebral foramen and boneless septum in the foramen is highly susceptible to Kummell's disease.

A comparative study of PSPVP and PSIBG in the treatment of stage II–III Kummell’s disease

BACKGROUND: Percutaneous kyphoplasty (PKP) or percutaneous vertebroplasty (PVP) are commonly employed for Kummell’s disease in stages II–III; however, these techniques produce some complications. OBJECTIVE: To compare the clinical efficacy and imaging results of percutaneous vertebroplasty + bone cement-augmented short-segment pedicle screw fixation (PSPVP) versus transpedicular intracorporeal bone grafting + pedicle screw fixation (PSIBG) in the treatment of stage II–III Kummell’s disease. METHODS: A total of 69 patients admitted between November 2017 and March 2021 were included in this study; 36 of these were treated with PSPVP, and 33 were treated with PSIBG. Patients in the two groups were compared in terms of perioperative, follow-up, and imaging data. RESULTS: No statistically significant differences were found between the two groups in terms of operation duration (P > 0.05). However, the PSPVP group was superior to the PSIBG group in terms of incision length, intraoperative blood loss, and length of stay (P < 0.05). All patients were followed up for more than 12 months. The VAS score, height of anterior vertebral margin, kyphosis Cobb angle, wedge angle of the affected vertebra at seven days after surgery and last follow-up, and the ODI index at the last follow-up of the two groups were significantly improved compared with figures before surgery (P < 0.05). Compared with values before surgery, no statistically significant differences were found in the height of the posterior vertebral margin in the PSPVP group at seven days after surgery and at the last follow-up (P > 0.05). There were also no statistically significant differences in the VAS score, ODI index, kyphosis Cobb angle, and wedge angle of the affected vertebra between the two groups at corresponding time points (P > 0.05). The heights of the anterior and posterior vertebral margins in the PSIBG group were better than those in the PSPVP group after surgery and at the last follow-up (P < 0.05). In the PSPVP group, a pedicle screw fracture occurred in one patient two months after surgery, while an upper adjacent vertebral fracture occurred in one patient eight months after surgery. CONCLUSION: Both PSPVP and PSIBG can achieve good early clinical efficacy in the treatment of stage II–III Kummell’s disease, with PSPVP being relatively less invasive while producing a poorer orthopedic effect and more complications than PSIBG.

Traditional Chinese medicine manipulative reduction combined with percutaneous vertebroplasty for treating type III Kummell's disease: A case report

BACKGROUND

A patient with type III Kummell's disease had a ruptured posterior cortex of the fractured vertebral body, which caused spinal cord compression. An open surgery was considered the best choice of operation. However, the patient and her family refused open surgery and instead demanded a minimally invasive surgical treatment such as percutaneous vertebroplasty (PVP). After preoperative discussion, we finally adopted the novel therapy of traditional Chinese medicine manipulative reduction (TCMMR) combined with PVP.

CASE SUMMARY

A patient with type III Kummell's disease exhibiting bone block-induced spinal cord compression was admitted to our hospital. She suffered from a variety of medical disorders but refused open surgery, and instead asked for PVP surgery. TCMMR, in parallel with PVP, was used to restore the height of the compressed vertebral body and reduce the symptoms of spinal cord compression by the bone block in order to strengthen the vertebral body and prevent further collapse. The surgery was very successful. The height of the compressed vertebra was restored, and the symptom of spinal cord compression by bone block was reduced successfully via TCMMR. The fractured vertebra was solidified by the PVP. The pain visual analog score declined from preoperative 7 scores to postoperative 2 scores, and the Frankel spinal cord scale increased from preoperative D degree to postoperative E degree.

CONCLUSION

The new method has advantages in treating patients with type III Kummell's disease who cannot be treated with open surgery.

Treatment of Kümmell’s disease following the occurrence of osteoporotic vertebral compression fracture

Background: The incidence of osteoporotic vertebral compression fracture (OVCF) is increasing with the increase in the elderly population. Kümmell’s disease following OVCF occurrence is not a rare complication and is frequently associated with severe pain or neurologic deficit with progressive kyphotic deformity. Kümmell’s disease initially meant post-traumatic delayed vertebral collapse, but now it is also termed nonunion, osteonecrosis, or intravertebral vacuum cleft, all of which suggest the disruption of the healing process.Current Concepts: The major pathogenesis of Kümmell’s disease is a vascular compromise caused by mechanical stress or intravascular pathology. The key radiologic sign to diagnose Kümmell’s disease is the presence of intravertebral vacuum cleft, observed using simple X-ray, computed tomography, or magnetic resonance imaging. Magnetic resonance imaging is the most useful diagnostic tool showing gas or fluid signals. The risk factors for the progression of Kümmell’s disease after OVCF include middle-column injury, confined low signal intensity on T2-weighted image, posterior wall combined fracture, kyphotic angle >10°, and a height loss >15%. Its treatment can be broadly classified as conservative treatment, bone cement injection, and surgical treatment. The appropriate treatment method is selected based on the pain intensity, neurological symptoms, and the severity of the kyphotic deformity.Discussion and Conclusion: Kümmell’s disease usually develops along with osteoporosis. Therefore, the treatment should be focused on relief from symptoms associated with Kümmell’s disease and osteoporosis. It is recommended that an anabolic agent should be administered after the diagnosis of Kümmell’s disease, regardless of the treatment modality.

Long-term efficacy and safety of bone cement-augmented pedicle screw fixation for stage III Kümmell disease

This study aimed to evaluate the efficacy and safety of bone cement-augmented pedicle screw fixation for stage III Kümmell disease. Twenty-five patients with stage III Kümmell disease who received bone cement-augmented pedicle screw fixation at the First Affiliated Hospital of Guangzhou University of Chinese Medicine between June 2009 and December 2015 were enrolled. All patients were females with a history of osteoporosis. The vertebral Cobb angle (V-Cobb angle), the fixed segment Cobb Angle (S-Cobb angle), pelvic parameters, visual Analogue Scale (VAS) score, and Oswestry Disability Index (ODI) were assessed preoperatively, postoperatively and at the final follow-up. Complications, loosening rate, operation time, and intraoperative bleeding were recorded. The average lumbar vertebral density T-value was − 3.68 ± 0.71 SD, and the average age was 71.84 ± 5.39. The V-Cobb angle, S-Cobb angle, and Sagittal Vertical Axis (SVA) were significantly smaller postoperatively compared to the preoperative values. The VAS and ODI at 1 month after surgery were 3.60 ± 1.00 and 36.04 ± 6.12%, respectively, which were both significantly lower than before surgery (VAS: 8.56 ± 1.04, ODI: 77.80 ± 6.57%). Bone cement-augmented pedicle screw fixation is a safe and effective treatment for stage III Kümmell disease. It can effectively correct kyphosis, restore and maintain sagittal balance, and maintain spinal stability.

The clinical results of treating Kummell's disease with mineralized collagen modified polymethyl methacrylate

To investigate the clinical results of treating Kummell's Disease by using mineralized collagen modified polymethyl methacrylate bone cement, 23 cases (23 vertebras) who sustained Kummell's Disease treated with mineralized collagen modified polymethyl methacrylate bone cement from July 2017 to February 2019 were reviewed retrospectively. The visual analogue scale, vertebral body height, Cobb angle, CT values pre-operation and post-operation as well as incidence of complications were observed. All the patients were successfully followed up with an average period of 11.3 months (ranging from 6 to 12 months). The patients could ambulate on the second day after the operation. The visual analogue scale scores significantly decreased from two days after the operation to the last follow-up compared with that before the operation (p < 0.05); the average vertebral height and local Cobb angle had significant recovery (p < 0.05); the CT value of the treated vertebra significantly increased compared with that before the operation (p < 0.05). Bone cement leakage occurred in one case, anterior edge leakage occurred in one case, and no clinical symptoms caused by bone cement leakage occurred. No re-fracture of the treated vertebral body or adjacent vertebral bodies were observed in the follow-ups. With good osteogenic activity and degradable absorption characteristics, mineralized collagen was compounded with the existing polymethyl methacrylate bone cement to reduce its strength in the vertebral body and enhance biocompatibility, the incidence of adjacent vertebral fractures and re-fractures within the injured vertebrae is significantly reduced, and good clinical results are obtained, which is worthy of popularization.

Percutaneous vertebral augmentation using drill rotation for osteoporotic vertebral compression fractures with intravertebral vacuum cleft

OBJECTIVE

To evaluate the efficacy of a new technique of percutaneous vertebral augmentation (PVA): drill rotation-cement injected under vacuum aspiration (DR-CIVAS) for vertebral compression fractures (OVCFs) with intravertebral vacuum cleft (IVC) sign.

MATERIALS AND METHODS

A retrospective study was conducted in 46 consecutive patients with OVCFs and IVC signs, who underwent PVA using DR-CIVAS (n = 22, DR-CIVAS group) or traditional technique without DR-CIVAS (n = 24, control group). The pre- and postoperative vertebral height and wedge angle change and visual analog scale (VAS), the volume of cement injected, incidences of cement leakage, and subsequent new vertebral compression fractures were evaluated between the two groups.

RESULTS

No significant difference was found in cement leakage incidences, pre- and postoperative VAS scores, vertebral height, and wedge angle change between the two groups. The mean cement volume was significantly higher (P < 0.001) in DR-CIVAS group (4.87 mL) than in the control group (3.58 mL). Of the 22 patients in DR-CIVAS group, the subsequent fractures occurred in 2 cases (9.1%) located in the nonadjacent levels. In the control group, the subsequent fractures occurred in 6 cases (25.0%) located in the adjacent level (n = 1) and the augmented levels (n = 5). Although DR-CIVAS group did not demonstrate a statistical reduction of the incidence of subsequent fractures (P = 0.25), the subgroup analysis revealed that subsequent fractures frequently involved the augmented level in the control group (P = 0.04).

CONCLUSIONS

PVA with DR-CIVAS technique is effective for OVCFs with IVC sign, with lower incidences of subsequent new vertebral compression fractures in the augmented vertebra.

Biomechanical finite element analysis of superior endplate collapse after thoracolumbar fracture surgery

Background

In the follow-up after internal fixation of thoracolumbar fractures, the imaging of some patients shows "crater-like" collapse of the superior endplate of the injured vertebra, with variable collapse area and depth, even involving the anterior edge of the vertebral body. Though many papers had described the phenomenon, but nearly no one did biomechanical research about this. So we did this research in a creative way by using finite element model.

Methods

A healthy male volunteer was selected. The 64-slice thin-section spiral computed tomography images at the level of T11-L3 were collected. Data were imported into Mimics 15.0 medical image processing software to establish three-dimensional finite element skeletal models of T11 to L3 containing only three-dimensional surface elements without entities. The model was assigned values and verified. Then the pedicle screw-rod system was added to this model, and five models containing the screw-rod system with different defect sizes as well as five models that simulated the removal of the screw-rod system were derived at the same time (the defect volume was 1/5, 2/5, 3/5, 4/5, or 5/5 of the anterior vertebral column, respectively). Biomechanical analysis was then performed on this basis.

Results

After the removal of the internal fixator, as defect volume increased, the stress difference between the 4/5 defect group and the 5/5 defect group had the greatest magnitude of combined stress under the seven working conditions. When the volume of the collapse defect reached 4/5 of the anterior column of the vertebral body, the concentration of stress increased significantly, suggesting that the risk of continued compression or even refracture of the injured vertebra increased if the internal fixator was removed at that time.

Conclusions

When the volume of the defect in the superior endplate of the injured vertebra reaches 4/5 of the anterior column, the removal of the internal fixator should be carefully considered to avoid refracture of the anterior column of the injured vertebra.

Application of Anchoring Technique in Unilateral Percutaneous Vertebroplasty for Neurologically Intact Kümmell's Disease

Purpose

We aimed to present our experience in anchoring technique and evaluate the efficacy and safety of unilateral percutaneous vertebroplasty in patients with neurologically intact Kümmell's disease.

Methods

From January 2014 to December 2017, 29 patients (17 males and 12 females) with neurologically intact Kümmell's disease were operated on using anchoring technique in unilateral percutaneous vertebroplasty (PVP). Ages of the enrolled patients ranged from 67 to 81 years (mean 73.8 years). Clinical efficacy was evaluated by back pain visual analogue scale (BP-VAS) score, Oswestry disability index (ODI) score, as well as the height of anterior border and the kyphotic angle of the involved vertebral body on a standing lateral radiograph. The safety of PVP was assessed by surgical-related complications, including bone cement leakage and neurological deficit.

Results

All 29 patients underwent the PVP procedure successfully. The mean operation time was 35 ± 12 min. And all patients were able to walk/ambulate with a thoracolumbar brace after 12 to 24 hours, staying in bed postoperatively. Significantly statistical differences were observed in both BP-VAS and ODI scores at each time point of follow-up when compared with the preoperative condition (P < 0.05). Besides, statistically significant improvement in radiographic measurements such as kyphotic angle and the height of the anterior border of the involved vertebral body between the preoperative and postoperative assessments was also observed (P < 0.05) and asymptomatic leakage of cement occurred in 7 of 29 cases (24.1%).

Conclusions

We considered that the anchoring technique in unilateral PVP could provide an effective and safe alternative for neurologically intact Kümmell's disease.

Comprehensive review on intravertebral intraspinal, intrajoint, and intradiscal vacuum phenomenon: From anatomy and physiology to pathology

The term 'vacuum phenomenon' (VP), is characterized by gas-like density areas due to a rapid increase in the joint space volume ('acute VP') or represent a chronic gas collection. It can occur within a collapsed vertebral body, the spinal canal, joints but mainly the intervertebral disc. Studies support that VP is originated by a dynamic process involving the balance between tissues' liquid and gaseous components, influenced by the duration and the depth of mechanical and metabolic alterations, by the nature of neighboring tissues and the variability in both pressure and permeability of disc or vertebral or joint structures. Prevalence of VP in the general population is about 2%, reaching 20% in the elderly with disc degeneration. Although it's often a random finding in asymptomatic patients, VP is an eventually painful expression of disc degeneration, or disc or vertebral fracture, or bone lesions. In sporadic cases, intradiscal gas can be expelled (all-in-one or gradually), resulting in a gaseous cyst, causing pain and neurological symptoms. Considering that spontaneous resolution and recurrence after surgery are both possible, most of the authors recommend conservative treatment in patients with intradiscal and intravertebral VP; occasionally percutaneous CT(computed tomography) -guided aspiration or vertebral stabilization.

Titanium mesh bone grafting combined with pedicle screw internal fixation for treatment of Ku[Combining Diaeresis]mmell disease with cord compression: A case report and literature review

RATIONALE

In 1891, Dr. Hermann Kümmell, a German surgeon, described a clinical entity characterized by the development of progressive painful kyphosis following an asymptomatic period of months or years after a minor spinal trauma, leading to a gradual collapse of the vertebra and dynamic instability, ultimately progressing to kyphosis with prolonged back pain and/or paraparesis. To date, the main pathologic eliciting event remains unclear, and no standard treatment or single effective treatment are available for Kümmell disease.

PATIENT CONCERNS

A 74-year-old woman presented with severe back pain and numbness of both legs for approximately 2 months.

DIAGNOSES

According to the clinical symptoms and imaging examinations, the patient was diagnosed with stage III Kümmell disease.

INTERVENTIONS

The patient underwent titanium mesh bone grafting combined with pedicle screw internal fixation.

OUTCOMES

Postoperative kyphosis was corrected, and the vertebra was reconstructed.

LESSONS

Kümmell disease is not a rare complication of osteoporotic vertebral compression fractures, and treatment of each patient must be individualized. The application of titanium mesh bone grafting combined with pedicle screw internal fixation is an effective treatment option for stage III Kümmell disease.

Comparison of Percutaneous Kyphoplasty and Bone Cement-Augmented Short-Segment Pedicle Screw Fixation for Management of Kümmell Disease

BACKGROUND The purpose of this study was to compare the efficacy of percutaneous kyphoplasty (PKP) and bone cement-augmented short segmental fixation (BCA+SSF) for treating Kümmell disease. MATERIAL AND METHODS Between June 2013 and December 2015, 60 patients were treated with PKP or BCA+SSF. All patients were followed up for 12-36 months. We retrospectively reviewed outcomes, including Oswestry Disability Index (ODI), visual analogue scale (VAS), and kyphotic Cobb angle. RESULTS VAS, ODI, and Cobb angle, measured postoperatively and at the final follow-up, were lower than those measured preoperatively in both groups (P<0.05). VAS, ODI, and Cobb angle measured postoperatively demonstrated no significant differences when compared with those measured at the final follow-up in the PKP group (P>0.05). In the BCA+SSF group, VAS and ODI at the final follow-up were lower than those measured postoperatively (P<0.05), but no significant difference was found in the Cobb angle (P>0.05). The PKP group had better VAS and ODI than the BCA+SSF group, postoperatively (P<0.05). No significant difference was found in VAS and ODI at the final follow-up (P>0.05) or the Cobb angle measured postoperatively and at the final follow-up (P>0.05) between the 2 groups. Operative time, blood loss, and hospital stay in the PKP group were lower than those in the BCA+SSF group (P<0.05). No significant difference was found in complications (P>0.05). CONCLUSIONS PKP patients had better early clinical outcomes, shorter operation times and hospital admission times, and decreased blood loss, but had similar complications, radiographic results, and long-term clinical outcomes compared with BCA+SSF patients.

Bone Cement-Augmented Short-Segment Pedicle Screw Fixation for Kümmell Disease with Spinal Canal Stenosis

Background

This study aimed to explore the feasibility and efficacy of bone cement-augmented short-segmental pedicle screw fixation in treating Kümmell disease.

Material/Methods

From June 2012 to June 2015, 18 patients with Kümmell disease with spinal canal stenosis were enrolled in this study. Each patient was treated with bone cement-augmented short-segment fixation and posterolateral bone grafting, and posterior decompression was performed when needed. All patients were followed up for 12–36 months. We retrospectively reviewed outcomes, including the Oswestry disability index (ODI), visual analog scale (VAS) score, anterior and posterior heights of fractured vertebrae, kyphotic Cobb angle, and neurological function by Frankel classification.

Results

The VAS grades, ODI scores, anterior heights of affected vertebrae, and kyphotic Cobb angles showed statistically significant differences between pre- and postoperative and between preoperative and final follow-up values (P<0.05), whereas the differences between postoperative and final follow-up values were not statistically significant (P>0.05). The differences between posterior vertebral heights at each time point were not statistically significant (P>0.05). Improved neurological function was observed in 12 cases at final follow-up. Three cases had complications, including asymptomatic cement leakage in 2 patients and delayed wound infection in 1 patient.

Conclusions

Bone cement-augmented short-segment pedicle screw fixation is safe and effective for treating Kümmell disease, and can achieve satisfactory correction of kyphosis and vertebral height, with pain relief and improvement in neurological function, with few complications.

Pathomechanisms and management of osteoporotic pain with no traumatic evidence

Introduction

Osteoporosis is a pathological state with an unbalanced bone metabolism mainly caused by accelerated osteoporotic osteoclast activity due to a postmenopausal estrogen deficiency, and it causes some kinds of pain, which can be divided into two types: traumatic pain due to a fragility fracture from impaired rigidity, and pain derived from an osteoporotic pathology without evidence of fracture. We aimed to review the concepts of osteoporosis-related pain and its management.

Methods

We reviewed clinical and basic articles on osteoporosis-related pain, especially with a focus on the mechanism of pain derived from an osteoporotic pathology (i.e., osteoporotic pain) and its pharmacological treatment.

Results

Osteoporosis-related pain tends to be robust and acute if it is due to fracture or collapse, whereas pathology-related osteoporotic pain is vague and dull. Non-traumatic osteoporotic pain can originate from an undetectable microfracture or structural change such as muscle fatigue in kyphotic patients. Furthermore, basic studies have shown that the osteoporotic state itself is related to pain or hyperalgesia with increased pain-related neuropeptide expression or acid-sensing channels in the local tissue and nervous system. Traditional treatment for osteoporotic pain potentially prevents possible fracture-induced pain by increasing bone mineral density and affecting related mediators such as osteoclasts and osteoblasts. The most common agent for osteoporotic pain management is a bisphosphonate. Other non-osteoporotic analgesic agents such as celecoxib have also been reported to have a suppressive effect on osteoporotic pain.

Conclusions

Osteoporotic pain has traumatic and non-traumatic factors. Anti-osteoporotic treatments are effective for osteoporotic pain, as they improve bone structure and the condition of the pain-related sensory nervous system. Physicians should always consider these matters when choosing a treatment strategy that would best benefit patients with osteoporotic pain.

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.

[Effectiveness comparison between two operations in treatment of unstable type Kümmell's disease]

Objective

To compare the effectiveness between short segmental fixation combined with vertebroplasty (SSF+VP) and short segmental pedicle screw fixation combined with bone graft (SSF+BG) in the treatment of unstable type Kümmell's disease so as to provide a reference for the selection of the surgical method.

Methods

Between March 2013 and February 2015, 48 patients with unstable type Kümmell's disease who were in accordance with the inclusive criteria were included in the study. SSF+VP were used in 25 cases (SSF+VP group) and SSF+BG in 23 cases (SSF+BG group). There was no significant difference in gender, age, disease duration, bone mineral density, fracture segment, and preoperative visual analogue scale (VAS), Oswestry disability index (ODI), and kyphotic Cobb angle between 2 groups ( P>0.05). The operation time and complications related to operation were recorded; the effectiveness was evaluated by VAS, ODI, and kyphotic Cobb angle.

Results

The operation time was (107.7±18.8) minutes in SSF+VP group and was (113.7±22.4) minutes in SSF+BG group, showing no significant difference between 2 groups ( t=-1.045, P=0.302). Bone cement leakage occurred in 6 cases of SSF+VP group, and incision delayed healing occurred in 1 case of SSF+BG group. All patients achieved bone graft fusion on X-ray films. The bone graft fusion time was (15.1±1.3) weeks in SSF+VP group and (15.7±1.8) weeks in SSF+BG group, showing no significant difference between 2 groups ( t=-1.361, P=0.180). The VAS, ODI, and kyphotic Cobb angle at immediate after operation and at last follow-up were significantly lower than preoperative ones ( P<0.05). The VAS, ODI, and kyphotic Cobb angle had no significant difference between at immediate and at last follow-up in SSF+VP group ( P>0.05). In SSF+BG group, VAS at last follow-up was significantly lower than that at immediate after operation ( P<0.05), but no significant difference was found in kyphotic Cobb angle and ODI ( P>0.05). SSF+VP group was significantly better than SSF+BG group in VAS at immediate after operation ( P<0.05), but SSF+BG group was significantly better than SSF+VP group at last follow-up ( P<0.05). There was no significant difference in kyphotic Cobb angle and ODI between 2 groups at immediate after operation and at last follow-up ( P>0.05).

Conclusion

SSF+BG can achieve satisfactory effectiveness in the treatment of unstable type Kümmell's disease, and it has the advantages of good bony healing, obvious improvement of pain, and low complication incidence when compared with SSF+VP.

Vacuum phenomenon

This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

Update of vertebral cementoplasty in porotic patients

Vertebroplasty (VP) is a percutaneous mini-invasive technique developed in the late 1980s as antalgic and stabilizing treatment in patients affected by symptomatic vertebral fracture due to porotic disease, traumatic injury and primary or secondary vertebral spine tumors. The technique consists of a simple metameric injection of an inert cement (poly-methyl-methacrylate, PMMA), through a needle by trans-peduncular, parapeduncular or trans-somatic approach obtaining a vertebral augmentation and stabilization effect associated with pain relief. The technique is simple and fast, and should be performed under fluoroscopy or CT guidance in order to obtain a good result with low complication rate. The aim of this paper is to illustrate the utility of VP, the indications-contraindications criteria, how to technically perform the technique using imaging guidance, and the results and complications of this treatment in patients affected by symptomatic vertebral compression fracture.

One-stage partial vertebrectomy, titanium mesh implantation and pedicle screw fixation in the treatment of thoracolumbar burst fractures through a posterior approach

OBJECTIVE

To analyze the clinical results of a partial vertebrectomy with titanium mesh implantation and pedicle screw fixation using a posterior approach to reconstruct the spine in the treatment of thoracolumbar burst fractures.

METHOD

From January 2006 to August 2008, 20 patients with severe thoracolumbar fractures were treated.For vertebral bodies associated with one injured intervertebral disk, subtotal vertebrectomy surgery and single-segment fusion were performed. For vertebral bodies with two injured adjacent intervertebral disks, partial vertebrectomy surgery and two-segment fusion were performed.

RESULTS

All 20 patients were followed up for 12 to 24 months (average of 18 months). There were no complications such as wound infections, hemopneumothorax or abdominal infections in any of the patients. The neurological status of all of the patients was improved by at least one American Spinal Injury Association grade by the last follow-up. The anterior vertebral body height was an average of 50.77% before surgery, 88.51% after surgery and 87.86% at the last follow up; the sagittal Cobb angle was improved, on average, from 26.15° to 5.39° and was 5.90° at the last follow up. The percentage of spinal stenosis was improved, on average, from 26.07% to 4.93%° and was 6.15% at the last follow up. There were significant differences in the anterior vertebral body height pre- and post-surgery and in the sagittal Cobb angle and the percentage of spinal stenosis (p<0) in all patients.

CONCLUSIONS

This surgical procedure is simple and can accomplish decompression, reduction, fixation and fusion of the spine in one stage. This approach could be widely used in orthopedics.

Value of forceps biopsy and kyphoplasty in Kümmell's disease

The diagnosis of Kümmell's disease mainly depends on clinical and radiologic findings. However, these are not the gold standards for diagnosing this disease; bone biopsy is required. The authors performed modified bone biopsy and cement-filling techniques during kyphoplasty and investigated the feasibility and efficacy of kyphoplasty for the treatment of Kümmell's disease. This study included 28 patients (9 men and 19 women; average age, 71.9 years) with Kümmell's disease. All patients underwent the modified biopsy procedure and kyphoplasty with the modified cement-filling technique. Treatment efficacy was evaluated using visual analog scale pain scores, Oswestry Disability Index scores, vertebral height, and Cobb angles pre- and postoperatively and at final follow-up. All patients tolerated the procedure well and had immediate back pain relief after kyphoplasty. Biopsy examination revealed necrotic bone in 24 patients and sparse cancellous bone in 2; it was unsuccessful in 2 patients. No severe complication occurred in any patient. Two patients had cement leakage but no clinical symptoms. All efficacy measures were significantly better at the postoperative assessments than the preoperative assessments (P<.05) but were similar at the postoperative and final follow-up assessments. Kyphoplasty is a relatively effective and safe method for treating Kümmell's disease when modified techniques are performed to prevent cement leakage, and forceps biopsy can be used in the differential diagnosis of this condition.

Posterior decompression and short segmental pedicle screw fixation combined with vertebroplasty for Kümmell's disease with neurological deficits

The aim of this study was to investigate the treatment of Kümmell’s disease with neurological deficits and to determine whether intravertebral clefts are a pathognomonic sign of Kümmell’s disease. A total of 17 patients who had initially been diagnosed with Kümmell’s disease were admitted, one patient was excluded from this study. Posterior decompression and vertebroplasty for the affected vertebrae were conducted. Pedicle screw fixation and posterolateral bone grafts were performed one level above and one level below the affected vertebrae. Vertebral tissue was extracted for histopathological examination. The mean time of follow-up was 22 months (range, 18 to 42 months). The anterior and middle vertebral heights were measured on standing lateral radiographs prior to surgery, one day postoperatively and at final follow-up. The Cobb angle, the visual analog scale (VAS) and the Frankel classification were used to evaluate the effects of the surgery. The VAS, anterior and middle vertebral heights and the Cobb angle were improved significantly one day postoperatively and at the final follow-up compared with the preoperative examinations (P<0.05). No significant differences were observed between the one-day postoperative results and those at final follow-up (P>0.05). The neurological function of all patients was improved by at least one Frankel grade. All patients in this study exhibited intravertebral clefts, and postoperative pathology revealed bone necrosis. One patient (not included in this study) showed an intravertebral cleft, but the pathology report indicated a non-Hodgkin’s lymphoma. The intravertebral cleft sign is not pathognomonic of Kümmell’s disease. Posterior decompression with short-segment fixation and fusion combined with vertebroplasty is an effective treatment for Kümmell’s disease with neurological deficits.

Kümmell's disease, an uncommon and complicated spinal disorder: a review

Kümmell's disease is an uncommon and complicated spinal condition first described in 1891. Patients develop a kyphosis in the lower thoracolumbar spinal region months to years after sustaining an otherwise asymptomatic minor spinal trauma. The patho physiology, clinical presentation, imaging and treatment options of this disease remain controversial. The most widely accepted hypothetical patho physiology is avascular osteonecrosis. The intravertebral vacuum cleft phenomenon is considered a radiographic sign of avascular osteonecrosis of the vertebral body and is highly suggestive of Kümmell's disease. Treatment options include nonsurgical and surgical treatment, and percutaneous vertebral augmentation. The primary aims of surgical treatment of Kümmell's disease are neural decompression and stabilization of the spinal column. Surgery can involve an anterior, posterior, or combined anterior and posterior approach. Surgery and percutaneous vertebral augmentation provide significant symptomatic relief, functional improvement and deformity correction. Treatment of this disease must be individualized according to the stage of disease and the experience and preference of the surgeon.

Union rates and prognostic variables of osteoporotic vertebral fractures treated with a rigid external support

Object

External supports serve as a traditional treatment option for osteoporotic vertebral fractures (OVFs). However, the role of external supports in the treatment of OVF remains inconclusive. The purpose of this study was to determine the role of a rigid external support in the healing of OVFs by prospectively evaluating union (fracture settling) rates and prognostic variables for patients suffering from an incident OVF.

Methods

Fifty-five patients with acute back pain were enrolled in this study after being diagnosed with an OVF based on MRI findings. Patients were treated using a plastic thoracolumbosacral orthosis (TLSO) and underwent follow-up at 2, 3, and 6 months. Vertebrae were referred to as “settled” when there was no dynamic mobility on sitting lateral and supine lateral radiographs. At the time of the 3- and 6-month follow-up visits, the patients were divided into 2 groups, the “settled group” and the “unsettled group.” Patients in these groups were compared with regard to clinical and radiographic features.

Results

Of the 55 patients enrolled, 53 patients were followed up for 6 months. There were 14 men and 39 women with an average age of 75.3 years. Fracture settling of the affected vertebra was defined in 54.7% of the patients at 2 months, in 79.2% at 3 months, and in 88.7% at 6 months. All 5 components of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire improved significantly both at 3 months and 6 months. Patients in the unsettled group exhibited a statistically greater likelihood of having fractures at the thoracolumbar junction, Type A3 fractures, and fractures with a diffuse low-intensity area on T2-weighted MRI studies at 3 months. In contrast, at 6 months, the only statistically significant difference between the groups was patient age.

Conclusions

The biomechanical disadvantages of OVFs (location, type, and size) adversely influencing the fracture healing were overcome by the treatment using a TLSO within 6 months. The authors' findings show that a TLSO plays a biomechanical role in the healing of OVFs.

Short-segment pedicle instrumentation with transpedicular bone grafting for nonunion of osteoporotic vertebral fractures involving the posterior edge

Most osteoporotic vertebral fractures (OVFs) can be treated successfully with conservative methods. In about 10% of patients, nonunion develops and warrants surgical management with minimally invasive procedures such as vertebroplasty and kyphoplasty. Nevertheless, for patients with nonunion fractures that involve the posterior vertebral body wall, vertebroplasty and kyphoplasty are relatively contraindicated due to the risk of extravertebral polymethylmethacrylate cement leakage through vertebral fracture cracks. To this end, we developed a method for pedicle screw fixation combined with transpedicular bone grafting for such a condition. Briefly, after posterior pedicle screw fixation and reduction in the affected vertebra, the demineralized bone matrix was inserted into the vertebral body via a 'bone grafting funnel' created through the pedicle of the affected vertebra. The current retrospective study analysed the safety and efficacy of this approach. A total of 12 patients who fulfilled the criteria were treated with this procedure. Visual analogue scale scores for back pain and anterior vertebral heights were recorded. At 3-month follow-up, pain was significantly relieved compared with presurgery and the anterior vertebral heights were successfully restored and maintained. In conclusion, short-segment pedicle instrumentation combined with transpedicular bone grafting is a useful alternative in the treatment of nonunion of OVFs with loss of posterior edge integrity.

Are intravertebral vacuum phenomena benign lesions?

We retrospectively reviewed plain radiographs from patients with four different diseases that can cause vertebral collapse: osteoporotic vertebral collapse, spinal infection, spinal metastasis, and multiple myeloma. The objective of the study was to find the percentages of intravertebral vacuum phenomena and vertebral collapse rates in the four groups. The vacuum phenomenon is often observed in osteoporotic compression fractures. However, these phenomena are rarely seen in spinal infection and malignant lesions. Whether the vacuum phenomenon is a benign indicator is not known. We retrospectively reviewed plain radiographs from four groups of patients, including 328 osteoporotic vertebral collapse patients, 317 spinal infection patients, 302 spinal metastasis patients, and 325 multiple myeloma patients. The pattern and occurrence rates of intravertebral vacuum phenomena and vertebral body collapse were analyzed. The occurrence rate of intravertebral vacuum phenomena in patients with osteoporotic vertebral collapse was approximately 18.9%. Only one case of intravertebral vacuum phenomena was observed in patients with spinal infection. Vacuum phenomena were not observed in patients with spinal metastasis. The occurrence rate of intravertebral vacuum phenomena in patients with multiple myeloma was 6.4%. The patterns of intravertebral vacuum phenomena were also analyzed. Intravertebral vacuum phenomena are common in patients with osteoporotic vertebral collapse. Most cases of intravertebral vacuum phenomena are of a benign nature. Moreover, intravertebral vacuum phenomena occur extremely rarely in patients with spinal infection. Such phenomena are also found in patients with multiple myeloma.

Rare metastatic adenocarcinoma to the spine infiltrating three adjacent foramen in lumbar vertebrae

An 83-year-old man presented with severe back pain and worsening neurodeficit. Lateral radiographs showed the presence of compression fractures of the L1 to L2 vertebral bodies. Computed tomography (CT) scan showed an intravertebral vacuum sign suggestive of ischemic fracture. Magnetic resonance imaging showed a large right retroperitoneal mass infiltrating the vertebral bodies and entering the spinal canal from L1 to L4 neural foramina. A fluid sign usually suggestive of acute compression fractures was seen near the superior end plate of the L1 vertebral body in our patient. Computed tomography-guided biopsy confirmed the diagnosis of metastatic adenocarcinoma. However, the primary site could not be found despite several investigations. It is usually thought that the primary tumor spreads to the spine through the valveless Batson's plexus or by direct arterial seeding into vertebral bodies. A paravertebral primary tumor such as a lymphoma, a primary tumor from the lungs, or a renal cell carcinoma can potentially infiltrate the vertebral bodies and enter the spinal canal through the neural foramen. But a large retroperitoneal metastatic mass from an unknown primary adenocarcinoma is a rare condition. No reports exist in the literature on a metastatic mass infiltrating vertebral bodies and then entering the epidural space through the 3 consecutive neural foramen. Thus, the pathogenesis of metastatic adenocarcinomas, particularly when the primary site is unknown, is not completely understood and can give a varied radiological presentation.

Symptomatic relevance of intravertebral cleft in patients with osteoporotic vertebral fracture

OBJECT

The present study was designed to determine clinical and radiographic characteristics of unhealed osteoporotic vertebral fractures (OVFs) and the role of fracture mobility and an intravertebral cleft in the regulation of pain symptoms in patients with an OVF.

METHODS

Patients who had persistent low-back pain for 3 months or longer and a collapsed thoracic or lumbar vertebra that had an intervertebral cleft and abnormal mobility were referred to as having unhealed OVFs. Twenty-four patients with an unhealed OVF and 30 patients with an acute OVF were compared with regard to several clinical and radiographic features including the presence of an intravertebral fluid sign. Subsequently, the extent of dynamic mobility of the fractured vertebra was analyzed for correlation with the patients' age, duration of symptoms, back pain visual analog scale (VAS) score, and performance status. Finally, in cases of unhealed OVFs, the subgroup of patients with positive fluid signs was compared with the subgroup of patients with negative fluid signs.

RESULTS

Patients with an unhealed OVF were more likely to have a crush-type fracture, shorter vertebral height of the fractured vertebra, and a fracture with a positive fluid sign than those with an acute OVF. The extent of dynamic mobility of the vertebra correlated significantly with the VAS score in patients with an unhealed OVF. In addition, a significant correlation with the extent of dynamic vertebral mobility with performance status was seen in patients with an unhealed OVF and those with an acute OVF. Of the 24 patients with an unhealed OVF, 14 had a positive fluid sign in the affected vertebra. Patients with a positive fluid sign exhibited a statistically significantly greater extent of dynamic vertebral mobility, a higher VAS score, a higher performance status grade, and a greater likelihood of having a crush-type fracture than those with a negative fluid sign. All but 1 patient with an unhealed OVF and a positive fluid sign had an Eastern Cooperative Oncology Group Performance Status Grade 3 or 4 (bedridden most or all of the time). In sharp contrast, all 10 patients with an unhealed OVF and a negative fluid sign were Grade 1 or 2.

CONCLUSIONS

Unhealed OVFs form a group of fractures that are distinct from acute OVFs regarding radiographic morphometry and contents of the intravertebral cleft. Dynamic vertebral mobility serves as a primal pain determinant in patients with an unhealed OVF and potentially in those with an acute OVF. Fluid accumulation in the intravertebral cleft of unhealed OVFs likely reflects long-term bedridden positioning of the patients in daily activity.

Conversion to hypertrophic vertebral pseudarthrosis following percutaneous vertebroplasty

To determine the role of percutaneous vertebroplasty (PVP) in bone formation and the union of vertebral pseudarthrosis, we analyzed 14 patients with an average follow-up duration of 21 months. Evaluation methods included back pain (visual analog scale: VAS), wedge angle, dynamic mobility, radiographic remodeling including callus and spur formation, and union status. The Student's t test was used for statistical analysis and a probability of less than 0.05 was determined as a significant difference. Back pain improved in all 14 patients with a VAS score of 57.8 +/- 23.5 mm (average +/- standard deviation) preoperatively and 14.7 +/- 16.4 mm at the final follow-up (P < 0.001). The wedge angle decreased from 21.6 degrees +/- 8.3 degrees (average +/- standard deviation) preoperatively to 13.2 degrees +/- 6.9 degrees at the final follow-up (P < 0.001). Callus formation was seen in four patients. Bony spurs were seen in the affected vertebra in preoperative radiographs in all patients, and were further developed to a solidified form during follow up after PVP. Dynamic mobility of the affected vertebrae was 6.9 +/- 2.9 mm preoperatively, which decreased to 1.1 degrees +/- 0.7 degrees at the final follow-up (P < 0.001). Notably, all patients showed the dynamic vertebral mobility of 2 mm or less. Nevertheless, only two patients exhibited the dynamic vertebral mobility of 0 mm at the final follow-up, which is referred to as bone union. These findings indicate that PVP serves as a mechanical stabilizer for vertebral pseudarthrosis, which leads to immediate pain relief and segmental bony responses.

Parametric characterization of spinal motions in osteoporotic vertebral fracture at level T12 with fluoroscopy

Vertebral fractures due to osteoporosis are a common skeletal disorder affecting the mobility of the patients, although little is known about the relationship between spinal kinematics and osteoporotic fracture. The purpose of this study was to characterize the motions of the thoracolumbar spine affected by osteoporotic vertebral fracture at level T12 and compare the results with those of non-fracture osteoporosis subjects. We examined the continuous segmental kinematics of the vertebrae, and describe the segmental motion of the spine when a fracture at T12 is present. Fluoroscopy sequences of the thoracolumbar spines during sagittal and lateral flexion were collected from 16 subjects with osteoporosis of their spine (6 with vertebral fractures at T12, 10 without a fracture). Vertebrae T10-L2 in each frame of the sequences were landmarked. Kinematic parameters were calculated based on the landmarks and motion graphs were constructed. Compared to the control subjects who did not have a fracture, fracture subjects had a more asymmetric lateral range of motion (RoM) and required a longer time to complete certain phases of the motion cycle which are parameterized as lateral flexion ratio and percentage of motion cycle, respectively. Prolonged deflection was more frequently found from the fracture group. Characterizing the motions of the fractured vertebra together with its neighboring vertebrae with these kinematic parameters is useful in quantifying the dysfunction and may be a valuable aid to tracking progress of treatment.