Promotion of Bone Formation in a Rat Osteoporotic Vertebral Body Defect Model via Suppression of Osteoclastogenesis by Ectopic Embryonic Calvaria Derived Mesenchymal Stem Cells.

Osteoporotic vertebral compression fractures (OVCFs) are the most prevalent fractures among patients with osteoporosis, leading to severe pain, deformities, and even death. This study explored the use of ectopic embryonic calvaria derived mesenchymal stem cells (EE-cMSCs), which are known for their superior differentiation and proliferation capabilities, as a potential treatment for bone regeneration in OVCFs. We evaluated the impact of EE-cMSCs on osteoclastogenesis in a RAW264.7 cell environment, which was induced by the receptor activator of nuclear factor kappa-beta ligand (RANKL), using cytochemical staining and quantitative real-time PCR. The osteogenic potential of EE-cMSCs was evaluated under various hydrogel conditions. An osteoporotic vertebral body bone defect model was established by inducing osteoporosis in rats through bilateral ovariectomy and creating defects in their coccygeal vertebral bodies. The effects of EE-cMSCs were examined using micro-computed tomography (µCT) and histology, including immunohistochemical analyses. In vitro, EE-cMSCs inhibited osteoclast differentiation and promoted osteogenesis in a 3D cell culture environment using fibrin hydrogel. Moreover, µCT and histological staining demonstrated increased new bone formation in the group treated with EE-cMSCs and fibrin. Immunostaining showed reduced osteoclast activity and bone resorption, alongside increased angiogenesis. Thus, EE-cMSCs can effectively promote bone regeneration and may represent a promising therapeutic approach for treating OVCFs.

Finite element analysis of precise puncture vertebral augmentation in the treatment of different types of osteoporotic vertebral compression fractures.

BACKGROUND: Osteoporosis vertebral compression fracture (OVCF) secondary to osteoporosis is a common health problem in the elderly population. Vertebral augmentation (VA) has been widely used as a minimally invasive surgical method. The transpedicle approach is commonly used for VA puncture, but sometimes, it is limited by the anatomy of the vertebral body and can not achieve good surgical results. Therefore, we propose the treatment of OVCF with precise puncture vertebral augmentation (PPVA). This study used finite element analysis to explore the biomechanical properties of PPVA in the treatment of osteoporotic vertebral compression fractures (OVCFs) with wedge, biconcave, and collapse deformities. METHOD: Three-dimensional finite element models of the fractured vertebral body and adjacent superior and inferior vertebral bodies were established using Computed Tomography (CT) data from patients with OVCF, both before and after surgery. Evaluate the stress changes of the wedged deformed vertebral body, biconcave deformed vertebral body, collapsed deformed vertebral body, and adjacent vertebral bodies before and after PPVA. RESULT: In vertebral bodies with wedge deformity and collapsed deformity, PPVA can effectively reduce the stress on the vertebral body but increases the stress on the vertebral body with biconcave deformity. PPVA significantly decreases the stress on the adjacent vertebral bodies of the wedge deformed vertebral body, and decreases the stress on the adjacent superior vertebral body of biconcave deformity and collapsed deformed vertebral bodies, but increases the stress on the adjacent inferior vertebral bodies. PPVA improves the stress distribution of the vertebral body and prevents high-stress areas from being concentrated on one side of the vertebral body. CONCLUSION: PPVA has shown positive surgical outcomes in treating wedge deformed and collapsed deformed vertebral bodies. However, its effectiveness in treating biconcave vertebral body is limited. Furthermore, PPVA has demonstrated favorable results in addressing adjacent superior vertebral body in three types of fractures.

[Imaging characteristics and surgical effect for symmetrical lumbar hemivertebrae].

Objective: To analyze the imaging characteristics and surgical effect for symmetrical lumbar hemivertebrae in pediatric patients. Methods: The data of 13 patients with hemivertebrae locating in the lumbar spine symmetrically were retrospectively analyzed, and all the patients were treated in Beijing Children's Hospital from January 2015 to September 2021. The mean age of the patients was 6.2 (2.9, 9.3) years. There were 8 males and 5 females. The data of coronal/sagittal plane including segmental Cobb angle, cranial/caudal compensatory curve, thoracic kyphosis, thoracolumbar kyphosis, sacral obliquity, and lumbar lordosis were recorded through long cassette spinal radiographs. Associated anomalies and the relationship between hemivertebrae and posterior component were recorded through computerized tomography (CT) and magnetic resonance imaging (MRI). All the patients received surgery, and their pre-and postoperative imaging data were compared. Results: A total of 26 hemivertebraes were found, in which 80.8% (21/26) located below L2. Hemivertebraes in 10 patients were separated by a mean 1-2 normal vertebrae. Most hemivertebraes along with the corresponding posterior component were unison (21/26, 80.8%). The Cobb angles of cranial compensatory curve (13.9°±7.2°) was more serious than that of caudal compensatory curve (5.5°±5.0°)(P=0.04). The lumbar lordosis and thoracic kyphosis was 20.2°±15.0° and 18.7°±9.2°, respectively. Six patients complicated with sacral obliquity, while 7 patients complicated with thoracolumbar lordosis. Associated anomalies were found in 6 (46.2%) patients through CT and MRI. Eleven patients received one-or two-stage posterior hemivertebrae resection with short segmental fusion, and 2 patients received one-stage hemivertebrae resection with long segmental fusion. All the surgery were completed successfully without serious complications such as nerve injury, infection, and implant failure. The mean follow-up period was (42.4±10.2) months. At the last follow-up point, the correction rate of segmental Cobb angle and cranial compensatory curve was 83.3%±15.6% and 38.1%±10.4%, respectively, showing significant improvement (P<0.05). Although the caudal compensatory curve, sacral obliquity, and thoracic kyphosis improved after surgery, the data showed no significant difference compared to that before surgery. Thoracolumbar lordosis in all patients were corrected. Conclusions: Most hemivertebraes in such spinal deformity locate in lower lumbar region with a high incidence of anomalies. Individualized treatment based on patients' condition is essential for the complicated spinal deformity.

Chest tube management following two row vertebral body tethering for adolescent idiopathic scoliosis.

BACKGROUND: The current gold standard of scoliosis correction procedures is still posterior spinal fusion, an extensively studied procedure. anterior vertebral body tethering is a newer surgical technique for the correction of scoliotic curves. Consequently, best practices have yet to be determined. METHODS: A single-institution, retrospective, review of all patients diagnosed with adolescent idiopathic scoliosis who underwent two row anterior vertebral body tethering between June 2020 and April 2022 was performed. RESULTS: Over the study period, 95 patients met inclusion: 79 females (83.2%) and 16 males (16.8%), age 14.4 ± 2.5 years, with a body mass index of 20.0 ± 2.9, and an average of 8.4 ± 2.1 levels treated. 28 (29.5%) procedures were for double curves and 67 (70.5%) for single curves. After tethering, a chest tube was positioned in each corrected side. A total of 123 chest tubes were analyzed, including 67 single curves and 28 double curves. The average chest tube duration was 2.5 ± 1.1 days and the average length of stay was 5.0 ± 2.0 days. The average chest tube output eight hours prior to removal was 61.1 ± 45.6 mL. There was no significant difference in average length of stay for patients who underwent correction of a single curve versus a double curve nor was there a difference in average length of stay or chest tube duration for revisions compared to primary procedures. For the entire cohort, the 30-day emergency department visit rate was 7.4% (n = 7) and the readmission rate was 4.2% (n = 4). CONCLUSIONS: This early review of a 2-year two row vertebral body tethering postoperative experience provides a report of a safe and effective approach to chest tube management at a single academic center.

Radiological Outcomes of Re-tethering for Adolescent Idiopathic Scoliosis: A 2-to-5-year Follow-Up Case Series After Index Vertebral Body Tethering Failure.

PURPOSE: Vertebral Body Tethering (VBT) has been shown to have a less predictable outcome compared to spinal fusion in patients with adolescent idiopathic scoliosis (AIS). Tether breakage is a common mechanical event that sometimes leads to loss of correction. No data has been published that evaluates the outcome of re-tethering in patients who underwent revision surgery for failed VBT, which was the purpose of this study. METHODS: This is an analysis of a prospectively collected single center database of 290 patients who have had VBT. Patients for this study were included if they have had re-tethering after failed VBT and a minimum follow up of 24 months after index surgery as well as a minimum follow up of 12 months after revision surgery. Revision surgeries included tether exchange, tether reinforcement and/or mono- and bisegmental lateral fusion. Main outcome of interest was curve magnitude at latest follow up. RESULTS: 11 patients were identified who received VBT for 16 curves of which 13 curves have had failed index surgery. Mean follow up from index surgery was 40 months, time between index and revision surgery was 22 months and latest follow up after revision surgery 19 months. Re-tethering resulted in an additional correction of 42% for thoracic and 63% for thoracolumbar curves. These results remained clinically stable with only minor loss of correction at final follow up. No patient underwent or was indicated for spinal fusion. CONCLUSION: Re-tethering is feasible and able to achieve additional correction and a sustainable result.

The efficacy of anterior vertebral body tethering in lenke type 6 curves for adolescent idiopathic scoliosis.

PURPOSE: Spinal fusion is the standard treatment for severe forms of adolescent idiopathic scoliosis (AIS). However, with the lowest instrumented vertebra that is usually located at L3 or L4, patients are prone to develop adjacent segment degeneration in the long term. Vertebral body tethering (VBT) as motion preserving technique has become an alternative for select patients with AIS. Several studies have presented the outcome after thoracic VBT but no study has analyzed the outcome after VBT for Lenke type 6 curves. METHODS: This is a retrospective single center data analysis of patients who have had bilateral VBT for Lenke type 6 curves and a minimum follow up of 24 months. Radiographic analysis was performed on several time points. Suspected tether breakages were additionally analyzed with respect to location and time at occurrence. RESULTS: 25 patients were included. Immediate thoracic curve correction was 55.4% and 71.7% for TL/L curves. Loss of correction was higher for TL/L curves and resulted in a correction rate of 48.3% for thoracic curves and 48.9% for TL/L curves at 24 months post-operatively. 22 patients were suspected to have at least one segment with a tether breakage. Three patients required a re-VBT but no patient received posterior spinal fusion. CONCLUSION: Bilateral VBT for Lenke type 6 curves is feasible and shows a significant curve correction for thoracic and TL/L curves at a minimum of 24 months post-operatively. Tether breakage rate and loss of correction remain an unfavorable observation that needs to be improved in the future.

Delayed hemothorax after anterior vertebral body tethering in adolescent idiopathic scoliosis: a case report.

PURPOSE: The aim of this case report is to report that delayed hemothorax is possible after anterior vertebral body tethering (aVBT) and to illustrate the course of treatment. METHODS: We present a 15-year-old boy with adolescent idiopathic scoliosis who underwent an anterior thoracoscopic assisted vertebral body tethering who developed a massive right-sided hemothorax 12 days post-operatively. A chest tube was placed to drain the hemothorax and later required embolectomy with tissue plasminogen activator (TPA) to drain the retained hemothorax. RESULTS: At 1 month follow up post discharge the patient was asymptomatic, and radiograph did not demonstrate evidence of residual hemothorax and scoliosis. We have followed this patient for 5 years postoperative and he continues to do well clinically and radiographically. CONCLUSIONS: Pulmonary complications are a known drawback of anterior thoracoscopic spinal instrumentation. Delayed hemothorax is possible after aVBT. In the case of a retained hemothorax, chest tube treatment with TPA is a safe and effective method of embolectomy.

[Application of self-stabilizing zero-profile three-dimensional printed artificial vertebral bodies for treatment of cervical spondylotic myelopathy].

Objective: To evaluate the safety and effectiveness of applying self-stabilizing zero-profile three-dimensional (3D) printed artificial vertebral bodies in anterior cervical corpectomy and fusion (ACCF) for cervical spondylotic myelopathy. Methods: A retrospective analysis was conducted on 37 patients diagnosed with cervical spondylotic myelopathy who underwent single-level ACCF using either self-stabilizing zero-profile 3D-printed artificial vertebral bodies ( n=15, treatment group) or conventional 3D-printed artificial vertebral bodies with titanium plates ( n=22, control group) between January 2022 and February 2023. There was no significant difference in age, gender, lesion segment, disease duration, and preoperative Japanese Orthopedic Association (JOA) score between the two groups ( P>0.05). Operation time, intraoperative bleeding volume, hospitalization costs, JOA score and improvement rate, incidence of postoperative prosthesis subsidence, and interbody fusion were recorded and compared between the two groups. Results: Compared with the control group, the treatment group had significantly shorter operation time and lower hospitalization costs ( P<0.05); there was no significant difference in intraoperative bleeding volume between the two groups ( P>0.05). All patients were followed up, with a follow-up period of 6-21 months in the treatment group (mean, 13.7 months) and 6-19 months in the control group (mean, 12.7 months). No dysphagia occurred in the treatment group, while 5 cases occurred in the control group, with a significant difference in the incidence of dysphagia between the two groups ( P<0.05). At 12 months after operation, both groups showed improvement in JOA scores compared to preoperative scores, with significant differences ( P<0.05); however, there was no significant difference in the JOA scores and improvement rate between the two groups ( P>0.05). Radiographic examinations showed the interbody fusion in both groups, and the difference in the time of interbody fusion was not significant ( P>0.05). At last follow-up, 2 cases in the treatment group and 3 cases in the control group experienced prosthesis subsidence, with no significant difference in the incidence of prosthesis subsidence ( P>0.05). There was no implant displacement or plate-screw fracture during follow-up. Conclusion: The use of self-stabilizing zero-profile 3D-printed artificial vertebral bodies in the treatment of cervical spondylotic myelopathy not only achieves similar effectiveness to 3D-printed artificial vertebral bodies, but also reduces operation time and the incidence of postoperative dysphagia.

[Treatment of cervical ossification of posterior longitudinal ligament with titanium alloy trabecular bone three-dimensional printed artificial vertebral body].

Objective: To evaluate the effectiveness of using titanium alloy trabecular bone three-dimensional (3D) printed artificial vertebral body in treating cervical ossification of the posterior longitudinal ligament (OPLL). Methods: A retrospective analysis was conducted on clinical data from 45 patients with cervical OPLL admitted between September 2019 and August 2021 and meeting the selection criteria. All patients underwent anterior cervical corpectomy and decompression, interbody bone graft fusion, and titanium plate internal fixation. During operation, 21 patients in the study group received titanium alloy trabecular bone 3D printed artificial vertebral bodies, while 24 patients in the control group received titanium cages. There was no significant difference in baseline data such as gender, age, disease duration, affected segments, or preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), vertebral height, and C 2-7Cobb angle ( P>0.05). Operation time, intraoperative blood loss, and occurrence of complications were recorded for both groups. Preoperatively and at 3 and 12 months postoperatively, the functionality and symptom relief were assessed using JOA scores, VAS scores, and NDI evaluations. The vertebral height and C 2-7 Cobb angle were detected by imaging examinations and the implant subsidence and intervertebral fusion were observed. Results: The operation time and incidence of complications were significantly lower in the study group than in the control group ( P<0.05), while the difference in intraoperative blood loss between the two groups was not significant ( P>0.05). All patients were followed up 12-18 months, with the follow-up time of (14.28±4.34) months in the study group and (15.23±3.54) months in the control group, showing no significant difference ( t=0.809, P=0.423). The JOA score, VAS score, and NDI of the two groups improved after operation, and further improved at 12 months compared to 3 months, with significant differences ( P<0.05). At each time point, the study group exhibited significantly higher JOA scores and improvement rate compared to the control group ( P<0.05); but there was no significantly difference in VAS score and NDI between the two groups ( P>0.05). Imaging re-examination showed that the vertebral height and C 2-7Cobb angle of the two groups significantly increased at 3 and 12 months after operation ( P<0.05), and there was no significant difference between 3 and 12 months after operation ( P>0.05). At each time point, the vertebral height and C 2-7Cobb angle of the study group were significantly higher than those of the control group ( P<0.05), and the implant subsidence rate was significantly lower than that of the control group ( P<0.05). However, there was no significant difference in intervertebral fusion rate between the two groups ( P>0.05). Conclusion: Compared to traditional titanium cages, the use of titanium alloy trabecular bone 3D-printed artificial vertebral bodies for treating cervical OPLL results in shorter operative time, fewer postoperative complications, and lower implant subsidence rates, making it superior in vertebral reconstruction.

Long-term effects of local radiotherapy on growth and vertebral features in children with high-risk neuroblastoma.

BACKGROUND: To evaluate the effects of local radiotherapy (RT) on growth, we evaluated the chronological growth profiles and vertebral features of children with high-risk neuroblastoma. METHODS: Thirty-eight children who received local photon or proton beam therapy to the abdomen or retroperitoneum between January 2014 and September 2019 were included. Simple radiography of the thoracolumbar spine was performed before and every year after RT. The height and vertical length of the irradiated vertebral bodies (VBs) compared with the unirradiated VBs (vertebral body ratio, VBR) were analyzed using the linear mixed model. Shape feature analysis was performed to compare the irradiated and unirradiated vertebrae. RESULTS: The follow-up was a median of 53.5 months (range, 21-81 months) after RT. A decline in height z-scores was mainly found in the early phase after treatment. In the linear mixed model with height, the initial height (fixed, p < 0.001), sex (time interaction, p = 0.008), endocrine dysfunction (time interaction, 0.019), and age at diagnosis (fixed and time interaction, both p = 0.002) were significant. Unlike the trend in height, the change in VBR (ΔVBR) decreased gradually (p < 0.001). The ΔVBR in the group that received more than 30 Gy decreased more than in the group that received smaller doses. In the shape feature analysis, the irradiated VBs changed to a more irregular surface that were neither round nor rectangular. CONCLUSION: The irradiated VBs in children were gradually restricted compared to the unirradiated VBs in long-term follow-up, and higher RT doses were significantly affected. Radiation-induced irregular features of VBs were observed.

Analysis of three-dimensional spine growth for vertebral body tethering patients at 2 and 5 years post operatively.

PURPOSE: Scoliosis can be treated with vertebral body tethering (VBT) as a motion-sparing procedure. However, the knowledge of how growth is affected by a tether spanning multiple levels is unclear in the literature. Three-dimensional true spine length (3D-TSL) is a validated assessment technique that accounts for the shape of the spine in both the coronal and sagittal planes. This study aimed to assess if 3D-TSL increases over a five-year period after VBT implantation in thoracic curves for idiopathic scoliosis. METHODS: Prospectively collected radiographic data from an international pediatric spine registry was analyzed. Complete radiographic data over three visits (post-operative, 2 years, and 5 years) was available for 53 patients who underwent VBT. RESULTS: The mean age at instrumentation of this cohort was 12.2 (9-15) years. The average number of vertebrae instrumented was 7.3 (SD 0.7). Maximum Cobb angles were 50° pre-op, which improved to 26° post-op (p < 0.001) and was maintained at 5 years (30°; p = 0.543). Instrumented Cobb angle was 22° at 5 years (p < 0.001 vs 5-year maximum Cobb angle). An accentuation was seen in global kyphosis from 29° pre-operative to 41° at 5 years (p < 0.05). The global spine length (T1-S1 3D-TSL) started at 40.6 cm; measured 42.8 cm at 2 years; and 44.0 cm at the final visit (all p < 0.05). At 5 years, patients reached an average T1-S1 length that is comparable to a normal population at maturity. Immediate mean post-operative instrumented 3D-TSL (top of UIV-top of LIV) was 13.8 cm two-year length was 14.3 cm; and five-year length was 14.6 cm (all p < 0.05). The mean growth of 0.09 cm per instrumented level at 2 years was approximately 50% of normal thoracic growth. Patients who grew more than 0.5 cm at 2 years had a significantly lower BMI (17.0 vs 19.0, p < 0.05) and smaller pre-operative scoliosis (48° vs 53°, p < 0.05). Other subgroup analyses were not significant for age, skeletal maturity, Cobb angles or number of spanned vertebras as contributing factors. CONCLUSIONS: This series demonstrates that 3D-TSL increased significantly over the thoracic instrumented levels after VBT surgery for idiopathic scoliosis. This represented approximately 50% of expected normal thoracic growth over 2 years.

Three-dimensional vertebral shape changes confirm growth modulation after anterior vertebral body tethering for idiopathic scoliosis.

PURPOSE: To evaluate three-dimensional (3D) vertebra and disk shape changes over 2 years following anterior vertebral body tether (AVBT) placement in patients with idiopathic scoliosis (IS). METHODS: Patients with right thoracic IS treated with AVBT were retrospectively evaluated. 3D reconstructions were created from biplanar radiographs. Vertebral body and disk height (anterior, posterior, left and right) and shape (wedging angle) were recorded over the three apical segments in the local vertebral reference planes. Changes in height and wedging were measured through 2 years postoperatively. Change in patient height was correlated with changes in the spine dimensions. RESULTS: Forty-nine patients (Risser 0-3, Sanders 2-4) were included. The mean age was 12.2 ± 1.4 years (range 8-14). The mean coronal curve was 51 ± 10° preoperatively, 31 ± 9° at first postoperative time point and 27 ± 11° at 2-year follow-up (p < 0.001). The mean patient height increased 8 cm by 2 years (p < 0.001). The left side of the spine (vertebra + disc) grew in height by 2.2 mm/level versus 0.7 mm/level on the right side (p < 0.001). This differential growth was composed of 0.5 mm/vertebral level and 1.0 mm/disk level. Evaluation of the change in disk heights showed significantly decreased height anteriorly (- 0.4 mm), posteriorly (- 0.3 mm) and on the right (- 0.5 mm) from FE to 2 years. Coronal wedging reduced 2.3°/level with 1.1°/vertebral level change and 1.2°/disk level. There was no differential growth in the sagittal plane (anterior/posterior height). Patient height change moderately correlated with 3D measures of vertebra + disk shape changes. CONCLUSIONS: Three-dimensional analysis confirms AVBT in skeletally immature patients results in asymmetric growth of the apical spine segments. The left (untethered) side length increased more than 3 × than the right (tethered) side length with differential effects observed within the vertebral bodies and disks, each correlating with overall patient height change.

Early-term outcome of apical fusion with vertebral body tethering for thoracolumbar curves in adolescent idiopathic scoliosis: a preliminary study.

INTRODUCTION: Vertebral body tethering (VBT) has become an alternative option for select patients with idiopathic scoliosis. However, studies have shown a high number of tether breakages, specifically after thoracolumbar (TL) VBT, that can have a negative impact on the outcome, when the breakage occurs within the first year after surgery. In order to overcome this problem, we have started to apply an apical fusion (AF) in combination with TL VBT for select patients. This study aims to analyze the outcome after AF plus VBT. METHODS: This is a retrospective single surgeon's data analysis. All patients were included who have had TL VBT after January 2022 and a follow-up of 12 months. Patients were grouped based on whether they only had VBT or VBT + AF. RESULTS: Twenty-five patients were analyzed (15 VBT, 10 VBT + AF). Both groups showed a significant curve correction for thoracic and TL curves. Minor loss of correction was observed in both groups. A significant difference was seen regarding early tether breakages, which were found in 60% of VBT patients and 10% of VBT + AF patients. CONCLUSION: The preliminary data shows a significant reduction of early tether breakages when TL VBT is applied in combination with AF.

Torque forces of expandable titanium vertebral body replacement cages during expansion and subsidence in the osteoporotic lumbar spine.

BACKGROUND: The application of expandable titanium-cages has gained widespread use in vertebral body replacement for indications such as burst fractures, tumors and infectious destruction. However, torque forces necessary for a satisfactory expansion of these implants and for subsidence of them into the adjacent vertebrae are unknown within the osteoporotic spine. METHODS: Six fresh-frozen human, osteoporotic, lumbar spines were dorsally instrumented with titanium implants (L2-L4) and a partial corpectomy of L3 was performed. An expandable titanium-cage was inserted ventrally and expanded by both residents and senior surgeons until fixation was deemed sufficient, based on haptic feedback. Torque forces for expansion were measured in Nm. Expansion was then continued until cage subsidence occurred. Torque forces necessary for subsidence were recorded. Strain of the dorsal rods during expansion was measured with strain gauges. FINDINGS: The mean torque force for fixation of cages was 1.17 Nm (0.9 Nm for residents, 1.4 Nm for senior surgeons, p = .06). The mean torque force for subsidence of cages was 3.1 Nm (p = .005). Mean peak strain of the dorsal rods was 970 µm/m during expansion and 1792 µm/m at subsidence of cages (p = .004). INTERPRETATION: The use of expandable titanium-cages for vertebral body replacement seems to be a primarily safe procedure even within the osteoporotic spine as torque forces required for subsidence of cages are nearly three times higher than those needed for fixation. Most of the expansion load is absorbed by straining of the dorsal instrumentation. Rod materials other than titanium may alter the torque forces found in this study.

More anterior bone loss in middle vertebra after contiguous two-segment cervical disc arthroplasty.

BACKGROUND: Contiguous two-segment cervical disc arthroplasty (CDA) is safe and effective, while post-operative radiographic change is poorly understood. We aimed to clarify the morphological change of the three vertebral bodies operated on. METHODS: Patients admitted between 2015 and 2020 underwent contiguous two-level Prestige LP CDA were included. The follow-up was divided into immediate post-operation (≤ 1 week), early (≤ 6 months), and last follow-up (≥ 12 months). Clinical outcomes were measured by Japanese Orthopedic Association (JOA) score, visual analogue score (VAS), and neck disability index (NDI). Radiographic parameters on lateral radiographs included sagittal area, anterior-posterior diameters (superior, inferior endplate length, and waist length), and anterior and posterior heights. Sagittal parameters included disc angle, Cobb angle, range of motion, T1 slope, and C2-C7 sagittal vertical axis. Heterotopic ossification (HO) and anterior bone loss (ABL) were recorded. RESULTS: 78 patients were included. Clinical outcomes significantly improved. Of the three operation-related vertebrae, only middle vertebra decreased significantly in sagittal area at early follow-up. The four endplates that directly meet implants experienced significant early loss in length. Sagittal parameters were kept within an acceptable range. Both segments had a higher class of HO at last follow-up. More ABL happened to middle vertebra. The incidence and degree of ABL were higher for the endplates on middle vertebra only at early follow-up. CONCLUSION: Our findings indicated that after contiguous two-segment CDA, middle vertebra had a distinguishing morphological changing pattern that could be due to ABL, which deserves careful consideration before and during surgery.

Coronal decompensation following thoracic vertebral body tethering in idiopathic scoliosis.

PURPOSE: Post-operative coronal decompensation (CD) continues to be a challenge in the treatment of adolescent idiopathic scoliosis (AIS). CD following selective spinal fusion has been studied. However, there is currently little information regarding CD following Vertebral Body Tethering (VBT). Thus, the goal of this study is to better understand the incidence and risk factors for CD after VBT. METHODS: Retrospective review of a prospective multicenter database was used for analysis. Inclusion criteria were patients undergoing thoracic VBT, a minimum 2-year follow-up, LIV was L1 or above, skeletally immature (Risser ≤ 1), and available preoperative and final follow-up AP and lateral upright radiographs. Radiographic parameters including major and minor Cobb angles, curve type, LIV tilt/translation, L4 tilt, and coronal balance were measured. CD was defined as the distance between C7PL and CSVL > 2 cm. Multiple logistic regression model was used to identify significant predictors of CD. RESULTS: Out of 136 patients undergoing VBT, 94 patients (86 female and 6 male) met the inclusion criteria. The mean age at surgery was 12.1 (9-16) and mean follow-up period was 3.4 years (2-5 years). Major and minor curves, AVR, coronal balance, LIV translation, LIV tilt, L4 tilt were significantly improved after surgery. CD occurred in 11% at final follow-up. Lenke 1A-R (24%) and 1C (26%) had greater incidence of CD compared to 1A-L (4%), 2 (0%), and 3 (0%). LIV selection was not associated with CD. Multivariate logistic regression analysis yielded 1A-R and 1C curves as a predictor of CD with the odds ratio being 17.0. CONCLUSION: CD occurred in 11% of our thoracic VBT patients. Lenke 1A-R and 1C curve types were predictors for CD in patients treated with VBT. There were no other preoperative predictors associated with CD.

Design of a new detachable pedicle screw based on medical optical imaging inspection to improve osteoporosis and enhance vertebral body revision effect.

Osteoporosis is a common bone disease that often leads to difficulty in vertebrae revision. Traditional pedicle screws are often complicated to operate and have poor visibility during implantation. A new detachable pedicle screw is needed to improve the revision effect. The aim of this study was to design a new detachable pedicle screw based on medical optical imaging to improve the outcome of vertebral revision in osteoporosis, and to improve operational feasibility and visibility. In this study, the parameters related to the degree of osteoporosis were obtained by optical imaging detection of the osteoporotic vertebral body. Then a new detachable pedicle screw was designed according to the test results to improve the effect of vertebral body revision. By preparing and optimizing the material and structure of the screw, it is ensured that it has sufficient mechanical strength and stability. Finally, the visibility and operability of the improved screw during implantation were verified by medical optical imaging. Compared with traditional screws, the new detachable pedicle screw can improve the vertebral body revision in the case of osteoporosis. The optical imaging test results show that the new screw has good visibility and maneuverability, providing more accurate guidance and positioning for the vertebral body revision operation.

Coronal vertical fracture of vertebral body following minimally invasive lateral lumbar interbody fusion: risk factor analysis in consecutive case series.

BACKGROUND: To investigate the incidence and risk factors of coronal vertical vertebral body fracture (CV-VBF) during lateral lumbar interbody fusion (LLIF) for degenerative lumbar disease. METHODS: Clinical data, including age, sex, body mass index, and bone mineral density, were reviewed. Radiological assessments, such as facet joint arthrosis, intervertebral disc motion, index disc height, and cage profiles, were conducted. Posterior instrumentation was performed using either a single or staged procedure after LLIF. Demographic and surgical data were compared between patients with and without VBF. RESULTS: Out of 273 patients (552 levels), 7 (2.6%) experienced CV-VBF. Among the 552 levels, VBF occured in 7 levels (1.3%). All VBF cases developed intraoperatively during LLIF, with no instances caused by cage subsidence during the follow-up period. Sagittal motion in segments adjacent to VBF was smaller than in others (4.6° ± 2.6° versus 6.5° ± 3.9°, P = 0.031). The average grade of facet arthrosis was 2.5 ± 0.7, indicating severe facet arthrosis. All fractures developed due to oblique placement of a trial or cage into the index disc space, leading to a nutcracker effect. These factors were not related to bone quality. CONCLUSIONS: CV-VBF after LLIF occurred in 2.6% of patients, accounting for 1.3% of all LLIF levels. A potential risk factor for VBF involves the nutcracker-impinging effect due to the oblique placement of a cage. Thorough preoperative evaluations and surgical procedures are needed to avoid VBF when considering LLIF in patients with less mobile spine.

Comparative analysis of anti-osteoporosis medications in preventing vertebral body fractures after balloon kyphoplasty.

This retrospective study compared the efficacy of anabolic agents (romosozumab and teriparatide) with that of alendronate in preventing subsequent vertebral body fractures (SVBFs) after balloon kyphoplasty (BKP). All anabolic agents significantly reduced SVBFs. Romosozumab was most effective in increasing bone mineral density (BMD) and completely suppressed distant vertebral body fractures. INTRODUCTION: To determine optimal anti-osteoporosis medications, we compared romosozumab and teriparatide to alendronate as a control from perioperative BKP to the 1st postoperative year for treatment and secondary fracture prevention in osteoporosis. METHODS: A total of 603 patients who underwent initial BKP for osteoporotic vertebral fractures were evaluated and categorized into five groups based on drug administration: romosozumab (group R, 155 patients), twice-weekly teriparatide (group TW, 48), weekly teriparatide (group W, 151), daily teriparatide (group D, 138), and alendronate (control) (group C, 111). The 1-year incidence of SVBFs, BMD change rate, and probability of requiring BKP were compared among the groups. RESULTS: SVBF incidence was 3.9%, 6.5%, 8.3%, 6.0%, and 14.4% in groups R, D, TW, W, and C, respectively, with all other groups exhibiting significantly lower rates than group C. The groups that administered the anabolic agents had a notably lower incidence of distant fractures than group C. Compared with group C, group R showed significantly higher BMD change rates in lumbar vertebral bodies at 4, 8, and 12 months and group D at 12 months. Anabolic agent groups exhibited significantly higher improvement rates than group C after conservative treatment alone. CONCLUSION: The anabolic agents were found to be more effective at reducing the incidence of SVBF (especially distant vertebral fractures) than alendronate. These agents decreased the rate of repeat BKP even after the occurrence of a fracture. Overall, the use of an anabolic agent for the treatment of osteoporosis after BKP is better than the use of alendronate, even when treatment is initiated in the perioperative stage.

Sex differences and age-related changes in vertebral body volume and volumetric bone mineral density at the thoracolumbar spine using opportunistic QCT.

Objectives: To quantitatively investigate the age- and sex-related longitudinal changes in trabecular volumetric bone mineral density (vBMD) and vertebral body volume at the thoracolumbar spine in adults. Methods: We retrospectively included 168 adults (mean age 58.7 ± 9.8 years, 51 women) who received ≥7 MDCT scans over a period of ≥6.5 years (mean follow-up 9.0 ± 2.1 years) for clinical reasons. Level-wise vBMD and vertebral body volume were extracted from 22720 thoracolumbar vertebrae using a convolutional neural network (CNN)-based framework with asynchronous calibration and correction of the contrast media phase. Human readers conducted semiquantitative assessment of fracture status and bony degenerations. Results: In the 40-60 years age group, women had a significantly higher trabecular vBMD than men at all thoracolumbar levels (p<0.05 to p<0.001). Conversely, men, on average, had larger vertebrae with lower vBMD. This sex difference in vBMD did not persist in the 60-80 years age group. While the lumbar (T12-L5) vBMD slopes in women only showed a non-significant trend of accelerated decline with age, vertebrae T1-11 displayed a distinct pattern, with women demonstrating a significantly accelerated decline compared to men (p<0.01 to p<0.0001). Between baseline and last follow-up examinations, the vertebral body volume slightly increased in women (T1-12: 1.1 ± 1.0 cm3; L1-5: 1.0 ± 1.4 cm3) and men (T1-12: 1.2 ± 1.3 cm3; L1-5: 1.5 ± 1.6 cm3). After excluding vertebrae with bony degenerations, the residual increase was only small in women (T1-12: 0.6 ± 0.6 cm3; L1-5: 0.7 ± 0.7 cm3) and men (T1-12: 0.7 ± 0.6 cm3; L1-5: 1.2 ± 0.8 cm3). In non-degenerated vertebrae, the mean change in volume was <5% of the respective vertebral body volumes. Conclusion: Sex differences in thoracolumbar vBMD were apparent before menopause, and disappeared after menopause, likely attributable to an accelerated and more profound vBMD decline in women at the thoracic spine. In patients without advanced spine degeneration, the overall volumetric changes in the vertebral body appeared subtle.