Thoracolumbar fractures patients undergoing posterior pedicle screw fixation can benefit from drainage.

PURPOSE: To explore whether it is necessary to put drain tubes after posterior pedicle screw fixation of thoracolumbar fractures. METHODS: From April 2020 to January 2023, a total of 291 patients with recent thoracolumbar fractures (AO type-A or type-B) who received the pedicle screw fixation operation were enrolled retrospectively. In 77 patients, drain tubes were used in the pedicle screw fixation surgery, while no drain tubes were placed in the other group. After gleaning demographic information and results of lab examination and imageology examination, all data were put into a database. Independent-sample t-tests, Pearson Chi-Square tests, Linear regression analysis, and correlation analysis were then performed. RESULTS: Compared to the control group, the drainage group had significantly lower postoperative CRP levels (P = 0.047), less use of antipyretics (P = 0.035), higher ADL scores (P = 0.001), and lower NRS scores (P < 0.001) on the 6th day after surgery. Other investigation items, such as demographic information, operation time, intraoperative blood loss, body temperature, and other preoperative and postoperative lab results, showed no significant differences. CONCLUSIONS: The use of a drain tube in the pedicle screw fixation of thoracolumbar fractures is correlated with the improvement of patients' living and activity ability and the reduction of inflammation, postoperative fever and pain.

Surgical management of lower limb radiculopathy following acute singe-level osteoporotic vertebral fracture of lower lumbar spine in geriatric patient: a retrospective study.

BACKGROUND: Radiculopathy of the lower limb after acute osteoporotic vertebral fractures (OVFs) in the lower lumbar spine is uncommon in geriatric patients. Moreover, surgical intervention is generally recommended in patients who are irresponsive to conservative treatment. Determining an optimum surgical strategy is challenging considering the poor general condition of this population. Thus, herein, we established an algorithm for surgically managing this clinical scenario, hoping to provide a reference for making a surgical decision. METHODS: We retrospectively studied patients who suffered from new-onset radiculopathy of the lower limb after acute single-level OVFs in the lower lumbar spine and eventually underwent surgical intervention at our department. Information on the demographics, bone quality, AO spine classification of the vertebral fracture, pre-existing degenerative changes, including foraminal stenosis and lumbar disc herniation, and surgical intervention type was collected. Additionally, clinical outcomes, including preoperative and postoperative visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI), and MacNab criterion for response to surgery, were evaluated. RESULTS: From September 2019 to December 2021, a total of 22 patients with a mean age of 68.59 ± 9.74 years were analyzed. The most involved vertebra was L5 (54.5%), followed by L4 (27.3%) and L3 (18.2%). Among the 22 patients, 15 (68.2%) were diagnosed with the A1 type fracture of AO classification, and among them, 11 (73.3%) were characterized by the collapse of the inferior end plate (IEP). Three patients (13.6%) suffered from A2-type fractures, whereas four patients (18.2%) suffered from A3-type fractures. Pre-existing degenerative changes were observed in 12 patients (54.5%) of the patients. A total of 16 patients (72.7%) were treated by percutaneous kyphoplasty (PKP). Additionally, three patients underwent posterior instrumentation and fusion, two patients underwent a secondary endoscopic foraminoplasty, and one patient underwent a secondary radiofrequency ablation. The mean follow-up period was 17.42 ± 9.62 months. The mean VAS scores for leg and back pain and ODI decreased significantly after the surgery (P < 0.05). The total satisfaction rate at the last follow-up was 90.9% per the Macnab criterion. CONCLUSION: Patients with OVFs in the IEP are predisposed to suffer from radiculopathy of the lower limb. PKP alone or in combination with other minimally invasive surgical strategies is safe and effective in treating stable fractures. Additionally, aggressive surgical intervention should be considered in patients with unstable fractures or severe foraminal encroachment.

The efficacy of machine learning models in forecasting treatment failure in thoracolumbar burst fractures treated with short-segment posterior spinal fixation.

BACKGROUND: Although short-segment posterior spinal fixation (SSPSF) has shown promising clinical outcomes in thoracolumbar burst fractures, the treatment may be prone to a relatively high failure rate. This study aimed to assess the effectiveness of machine learning models (MLMs) in predicting factors associated with treatment failure in thoracolumbar burst fractures treated with SSPSF. METHODS: A retrospective review of 332 consecutive patients with traumatic thoracolumbar burst fractures who underwent SSPSF at our institution between May 2016 and May 2023 was conducted. Patients were categorized into two groups based on treatment outcome (failure or non-failure). Potential risk factors for treatment failure were compared between the groups. Four MLMs, including random forest (RF), logistic regression (LR), support vector machine (SVM), and k-nearest neighborhood (k-NN), were employed to predict treatment failure. Additionally, LR and RF models were used to assess factors associated with treatment failure. RESULTS: Of the 332 included patients, 61.4% were male (n = 204), and treatment failure was observed in 44 patients (13.3%). Logistic regression analysis identified Load Sharing Classification (LSC) score, lack of index level instrumentation, and interpedicular distance (IPD) as factors associated with treatment failure (P < 0.05). All models demonstrated satisfactory performance. RF exhibited the highest accuracy in predicting treatment failure (accuracy = 0.948), followed by SVM (0.933), k-NN (0.927), and LR (0.917). Moreover, the RF model outperformed other models in terms of sensitivity and specificity (sensitivity = 0.863, specificity = 0.959). The area under the curve (AUC) for RF, LR, SVM, and k-NN was 0.911, 0.823, 0.844, and 0.877, respectively. CONCLUSIONS: This study demonstrated the utility of machine learning models in predicting treatment failure in thoracolumbar burst fractures treated with SSPSF. The findings support the potential of MLMs to predict treatment failure in this patient population, offering valuable prognostic information for early intervention and cost savings.

Comparison Clinical Outcomes of Posterior Short Segment Transpedicular Fixation with or without Injured Vertebra Fixation in Thoracolumbar Burst Fracture: A Retrospective Study.

AIM: To evaluate and compare clinical outcomes between the posterior short-segment pedicle fixation with injured vertebra fixation (PSPFI) and fixation without injured vertebra fixation (PSPF) for thoracolumbar burst fracture (TLBF). MATERIAL AND METHODS: In this retrospective study, a total of 78 patients with TLBF were included and assigned to PSPFI (n=46) and PSPF (n=32) groups. The operative time, blood loss, perioperative complications, Oswestry disability index (ODI), and visual analog pain score (VAS) were examined immediately after surgery, 1 month, 3 months, and 1 year after surgery. Moreover, the postoperative vertebral height correction rate and postoperative Cobb angle correction rate were examined immediately and 1 year after surgery, as well as the corrected vertebral height loss rate and Cobb angle correction loss rate. RESULTS: No significant difference was identified in terms of operative time, blood loss, perioperative complications, ODI, and VAS after surgery (p > 0.05) between the PSPFI and PSPF groups. Moreover, the postoperative vertebral height correction rate and postoperative Cobb angle correction rate showed no difference between the groups as well. However, the PSPFI group had a significantly lower loss rate in terms of corrected vertebral height loss rate and Cobb angle correction loss rate than the PSPF group 1 year after surgery (p < 0.05). CONCLUSION: PSPFI and PSPF achieve similar clinical outcomes. However, posterior short-segment pedicle fixation with injured vertebra significantly maintains vertebral height correction rate and Cobb angle correction rate, which serve as a better choice for the treatment of TLBF.

Comparison Between Intraoperative Target Area Cement-Enhanced Percutaneous Vertebroplasty and Conventional Percutaneous Vertebroplasty for Osteoporotic Thoracolumbar Non-Total Vertebral Fractures.

AIM: To compare the efficacy and feasibility of target area cement-enhanced percutaneous vertebroplasty (PVP) and conventional PVP in osteoporotic thoracolumbar non-total vertebral fractures. MATERIAL AND METHODS: Retrospective analysis of one hundred and two patients treated in our hospital from March 2020 to May 2021 and divided into groups A (targeted) and B (conventional PVP). The Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), anterior vertebral height ratio, intraoperative bleeding, operative time, bone cement volume, complications, and refracture of the injured vertebra were evaluated in both groups. RESULTS: The 2 days and 1-year post-operative VAS and ODI scores improved significantly in both groups (p < 0.05). The 2 days post-operative VAS and ODI scores were better in group A (p < 0.05), and there was no significant difference in the scores between the groups at the last follow-up (p > 0.05). The anterior vertebral height ratios were significantly higher in both groups 2 days postoperatively (p < 0.05); however, there was no significant difference in the 2 days and 1-year post-operative ratios in group A (p > 0.05). The anterior vertebral height ratio reduced in group B after 1 year compared to the 2 days post-operative value (p < 0.05). There was no statistical difference in intraoperative bleeding and the operative time between the groups (p > 0.05), and the bone cement volume was lesser in group A (p < 0.05). Six patients in group A and four patients in group B demonstrated cement leakage, the difference was not statistically significant (p > 0.05). Three patients in group A and 11 patients in group B demonstrated refracture, the difference was statistically significant (p < 0.05). CONCLUSION: Target area cement-enhanced PVP can effectively relieve short-term pain and functional disability and reduce the long-term possibility of secondary collapse. Therefore, it is a technically feasible and efficacious method for the treatment of osteoporotic thoracolumbar non-total vertebral fractures.

Double Level Non-Contiguous Traumatic Lumbar Disc Herniation Presenting With Cauda Equina Syndrome: A Case Report and Literature Review.

CASE: A 52-year-old man presented with cauda equina syndrome after a motorcycle accident. Magnetic resonance imaging revealed traumatic disc herniation, at L2-L3 and L5-S1 levels without bony injury. He was managed successfully by wide laminectomy and microdiscectomy at both levels with complete neurological recovery at 2-month follow-up. CONCLUSION: With a reported incidence of 0.4%, traumatic disc herniation in the lumbar region is an uncommon occurrence that may resemble a spinal epidural hematoma in acute trauma. Although MRI may not reliably differentiate spinal epidural hematoma from disc herniation, urgent surgical intervention may be required in profound neurological deficits.

Adjacent vertebral fractures in the lumbar and thoracic spine after balloon kyphoplasty: A finite element analysis.

The purpose of the present study was to mechanically verify after vertebral augmentation (AVA) scores using a finite element method (FEM) with accurate material constants of balloon kyphoplasty (BKP) cement. Representative cases with AVA scores of 1 (case 1), 3 (case 2), and 5 (case 3) among patients with vertebral body fractures who underwent BKP were analyzed. A FEM model consisting of 5 vertebral bodies was created, including the injured vertebral body in each case. The amount of displacement for each load (up to 4000 N) between the upper and lower vertebral bodies of each model was measured. Young modulus of the BKP cement was calculated from actual measurements using the EZ-Test EZ-S (Shimadzu Corporation, Kyoto, Japan). In all cases, the number of shell elements (209,296-299,876), solid elements (1913,029-2417,671), and nodes (387,848-487,756) were similar, indicating that FEM modeling was comparable among the cases. Young modulus of BKP cement, calculated using EZ-Test EZ-S, was 572 MPa. Fractures were detected by compressive forces of 3300 N (upper) and 3300 N (lower), 3000 N (upper) and 3100 N (lower), and 1200 N (upper) and 1200 N (lower) in cases 1, 2, and 3, respectively. The AVA scoring system was mechanically verified using the accurate material constants of BKP cement. A multicenter survey and external validation are therefore required for the clinical implementation of the AVA score.

A reduction method for anterior opening displacement in thoracolumbarvertebral fractures with diffuse idiopathic skeletal hyperostosis using the skull clamp-assisted position.

Diffuse idiopathic skeletal hyperostosis (DISH) frequently occurs in the spine, resulting in unstable fractures. Treating thoracolumbar fractures in patients with DISH is often difficult because the anterior opening of the vertebral body is exacerbated by dislocation in the prone position, making reduction difficult. In this study, we introduced a novel skull clamp-assisted positioning (SAP) technique. The patient is placed in a supine position with a skull clamp used in cervical spine surgery before surgery to prevent the progression of dislocation and to restore the patient's position. Using this method, the mean difference in local kyphosis angle improved from -2.9 (±8.4)° preoperatively to 10.9 (±7.7)° postoperatively. Furthermore, posterior displacement decreased from a preoperative mean of 5.5 (±4.3) mm to 0.3 (±0.7) mm postoperatively. Complications such as neurological sequelae, implant fracture, and surgical site infection were not observed through one year of postoperative follow-up. SAP may decrease invasiveness and complications. Longer-term studies and larger sample sizes are needed to establish long-term efficacy and benefits.

Surgical outcomes of anterior column reconstruction for spinal fractures caused by minor trauma-preoperative examination of the number of intervertebral bone bridges is key to obtaining good bone fusion.

BACKGROUND: To achieve good bone fusion in anterior column reconstruction for vertebral fractures, not only bone mineral density (BMD) and bone metabolism markers but also lever arms due to bone bridging between vertebral bodies should be evaluated. However, until now, no lever arm index has been devised. Therefore, we believe that the maximum number of vertebral bodies that are bony and cross-linked with the contiguous adjacent vertebrae (maxVB) can be used as a measure for lever arms. The purpose of this study is to investigate the surgical outcomes of anterior column reconstruction for spinal fractures and to determine the effect of bone bridging between vertebral bodies on the rate of bone fusion using the maxVB as an indicator of the length of the lever arm. METHODS: The clinical data of 81 patients who underwent anterior column reconstruction for spinal fracture between 2014 and 2022 were evaluated. The bone fusion rate, back pain score, between the maxVB = 0 and the maxVB ≥ 2 patients were adjusted for confounding factors (age, smoking history, diabetes mellitus history, BMD, osteoporosis drugs, surgical technique, number of fixed vertebrae, materials used for the anterior props, etc.) and analysed with multivariate or multiple regression analyses. The bone healing rate and incidence of postoperative back pain were compared among the three groups (maxVB = 0, 2≦maxVB≦8, maxVB ≧ 9) and divided by the maxVB after adjusting for confounding factors. RESULTS: Patients with a maxVB ≥ 2 had a significantly higher bone fusion rate (p < 0.01) and postoperative back pain score (p < 0.01) than those with a maxVB = 0. Among the three groups, the bone fusion rate and back pain score were significantly higher in the 2≦maxVB≦8 group (p = 0.01, p < 0.01). CONCLUSIONS: Examination of the maxVB as an indicator of the use of a lever arm is beneficial for anterior column reconstruction for vertebral fractures. Patients with no intervertebral bone bridging or a high number of bone bridges are in more need of measures to promote bone fusion than patients with a moderate number of bone bridges are.

Hybrid kyphoplasty with short-versus intermediate- and long-segment pedicle screw fixations for the management of thoracolumbar burst fractures.

BACKGROUND: This study aimed to determine if the hybrid short-segment (HSS) technique is a good alternative to the intermediate-segment (IS) and long-segment (LS) techniques in pedicle screw fixations for acute thoracolumbar burst fractures (TLBFs). METHODS: In this retrospective evaluation, we examined 43 patients who underwent surgical treatments, including one- or two-level suprajacent (U) and infrajacent (L) pedicle screw fixations, for acute single-level TLBFs with neurological deficits between the T11 and L2 levels from July 2013 to December 2019. Among these patients, 15 individuals underwent HSS (U1L1), 12 received IS (U2L1), and 16 underwent LS (U2L2) fixations. Supplemental kyphoplasty of the fractured vertebral bodies was performed exclusively in the HSS group. Our analysis focused on assessing blood loss and surgical duration. Additionally, we compared postoperative thoracolumbar kyphotic degeneration using the data on Cobb angles on lateral radiographic images acquired at three time points (preoperatively, postoperative day 1, and follow-up). The end of follow-up was defined as the most recent postoperative radiographic image or implant complication occurrence. RESULTS: Blood loss and surgical duration were significantly lower in the HSS group than in the IS and LS groups. Additionally, the HSS group exhibited the lowest implant complication rate (2/15, 13.33%), followed by the LS (6/16, 37.5%) and IS (8/12, 66.7%) group. Implant complications occurred at a mean follow-up of 7.5 (range: 6-9), 9 (range: 5-23), and 7 (range: 1-21) months in the HSS, IS, and LS groups. Among these implant complications, revision surgeries were performed in two patients in the HSS group, two in the IS group, and one in the LS group. One patient treated by HSS with balloon kyphoplasty underwent reoperation because of symptomatic cement leakage. CONCLUSIONS: The HSS technique reduced intraoperative blood loss, surgical duration, and postoperative implant complications, indicating it is a good alternative to the IS and LS techniques for treating acute single-level TLBFs. This technique facilitates immediate kyphosis correction and successful maintenance of the corrected alignment within 1 year. Supplemental kyphoplasty with SpineJack® devices and high-viscosity bone cements for anterior reconstruction can potentially decrease the risk of cement leakage and related issues.

Assessing injury risks of reclined occupants in a frontal crash preceded by braking with varied seatbelt designs using the SAFER Human Body Model.

OBJECTIVE: This study investigated the effects of different seatbelt geometries and load-limiting levels on the kinematics and injury risks of a reclined occupant during a whole-sequence frontal crash scenario, using simulations with the Active SAFER Human Body Model (Active SHBM). METHODS: The Active SHBM was positioned in a reclined position (50°) on a semi-rigid seat model. A whole-sequence frontal crash scenario, an 11 m/s2 Automated Emergency Braking (AEB) phase followed by a frontal crash at 50 km/h, was simulated. The seatbelt geometry was varied using either a B-pillar-integrated (BPI) or Belt-in-seat (BIS) design. The shoulder belt load-limiting level of the BPI seatbelt was also varied to achieve either similar shoulder belt forces (BPI_Lower_LL) or comparable upper body displacements (BPI_Higher_LL) to the BIS seatbelt. Kinematics of different body regions and seatbelt forces were compared. The risks of sustaining a mild traumatic brain injury (mTBI), two or more fractured ribs (NFR2+), and lumbar spine vertebral fractures were also compared. RESULTS: During the pre-crash phase, head, first thoracic vertebra, and first lumbar vertebra displacements were greater with the BPI seatbelt than with the BIS, mainly due to the lack of initial contact between the torso and the seatbelt. Pelvis pre-crash displacements, however, remained consistent across seatbelt types. In the in-crash phase, variations in shoulder belt forces were directly influenced by the different load-limiting levels of the shoulder belt. The mTBI (around 20%) and NFR2+ (around 70-100%) risks were amplified with BPI seatbelts, especially at higher load-limiting force. However, the BPI design demonstrated reduced lumbar spine fracture risks (from 30% to 1%). CONCLUSIONS: The BIS seatbelt appears promising, as seen with the reduced mTBI and NFR2+ risks, for ensuring the protection of reclined occupants in frontal crashes. However, additional solutions, such as lap belt load limiting, should be considered to reduce lumbar spine loading.

[Effectiveness of unilateral biportal endoscopy combined with percutaneous pedicle screw fixation in treatment of lumbar burst fractures with neurological symptoms].

Objective: To evaluate the effectiveness of spinal canal decompression assisted by unilateral biportal endoscopy (UBE) and percutaneous uniplanar pedicle screw internal fixation in the treatment of lumbar burst fractures with neurological symptoms. Methods: Between June 2021 and December 2022, 10 patients with single level lumbar burst fracture with neurological symptoms were treated with spinal canal decompression assisted by UBE and percutaneous uniplanar pedicle screw internal fixation. There were 7 males and 3 females with an average age of 43.1 years (range, 21-57 years). The injured vertebrae located at L 1 in 2 cases, L 2 in 4 cases, L 3 in 3 cases, and L 4 in 1 case. There were 7 cases of AO type A3 fractures and 3 cases of AO type A4 fractures. The total operation time, the time of operation under endoscopy, and complications were recorded. Pre- and post-operative visual analogue scale (VAS) score and American Spinal Injury Association (ASIA) scale (grading A-E corresponding to assigning 1-5 points for statistical analysis) were used to evaluate effectiveness. X-ray film and CT were performed to observe the fracture healing, and the ratio of anterior vertebral body height, Cobb angle, and rate of spinal canal invasion were measured to evaluate the reduction of fracture. Results: All operations was successfully completed, and the spinal canal decompression and the bone fragment in spinal canal reduction completed under the endoscopy. Total operation time was 119 minutes on average (range, 95-150 minutes), and the time of operation under endoscopy was 46 minutes on average (range, 35-55 minutes). There was no complication such as dural sac, nerve root, or blood vessel injury during operation. All incisions healed by first intention. All patients were followed up 18.7 months on average (range, 10-28 months). The VAS score after operation significantly decreased when compared with that before operation ( P<0.05), and further improved at last follow-up ( P<0.05). The ASIA scale after operation significantly improved when compared with that before operation ( P<0.05), and there was no significant difference ( P>0.05) in the ASIA scale between at 1 week after operation and at last follow-up. The imaging examination showed that the screw position was good and the articular process joint was preserved. During follow-up, there was no loosening, fracture, or fixation failure of the internal fixation. The ratio of anterior vertebral body height and Cobb angle significantly improved, the rate of spinal canal invasion significantly decreased after operation ( P<0.05), and without significant loss of correction during the follow-up ( P>0.05). Conclusion: Spinal canal decompression assisted by UBE and percutaneous uniplanar pedicle screw fixation is a feasible minimally invasive treatment for lumbar burst fractures with neurological symptoms, which can effectively restore the vertebral body sequence, as well as relieve the compression of spinal canal, and improve the neurological function.

Finite element analysis of different pedicle screw internal fixations for first lumbar vertebral fracture in different sports conditions.

OBJECTIVE: Lumbar fractures are the most common spinal injuries, and surgery is required for severe fracture. This study aimed to investigate the variations in motion and stress in varying states of activity after minimally invasive and traditional open pedicle screw placement for L1 vertebral fracture stabilization. METHODS: We studied a male volunteer (26 years old) with no history of chronic back pain or lumbar spine trauma. We used the finite element method for this investigation. Using finite element software, we created a three-dimensional model of L1 vertebral compression fracture. We also constructed models for four percutaneous pedicle screws spanning the fractured vertebra and four screws traversing the damaged vertebra with transverse fixation. RESULTS: In all three-dimensional movement directions, the open pedicle fixation system experienced maximum stress higher than its percutaneous counterpart. With axial spinal rotation, von Mises stress on the traditional open pedicle screw was considerably lower than that with percutaneous pedicle fixation, but peak stress was elevated at the transverse connection. Traditional open pedicle fixation displayed less maximum displacement than percutaneous pedicle internal fixation. CONCLUSIONS: During axial spinal movements, high peak stress is observed at the transverse connection. Patients should avoid excessive axial rotation of the spine during recovery.

The effect of the size of pedicle screw on the long-term radiological and clinical results of short-segment posterior instrumentation in the management of thoracolumbar vertebral fractures.

OBJECTIVE: It was aimed at evaluating the effect of the size of the pedicle screw placed on the fractured vertebra on the long-term radiological and clinical results of short-segment posterior instrumentation applied in the surgical treatment of thoracolumbar vertebral fractures. METHODS: This retrospective study included 36 patients who underwent short-segment posterior instrumentation surgery for a single-level thoracolumbar (T11-L2) fracture between January 2015 and March 2021. The patients included in the study were divided into 2 groups according to the size of the pedicle screw placed in the fractured vertebra (group A: intermediate screw 4.5 mm, ≤35 mm+less than 50% of the vertebral corpus length, m/f: 13/4, n: 17, age: 36.5; group B: intermediate screw 5.5 mm, ≥40 mm+more than 70% of the vertebral corpus length, m/f: 11/8, n: 19, age: 42.6). All patients were periodically evaluated clinically and radiologically. Vertebral compression angle (VCA), anterior and posterior vertebral body height (ABH-PBH), intraoperative parameters (instrumentation time and intraoperative fluoroscopy number), and complications were compared between the 2 groups. RESULTS: Both groups were comparable with respect to age, sex, level of injury, AO classification, mechanism of injury, and American Spinal Cord Injury Association impairment scale. Restoration of VCA and vertebral corpus heights was achieved sufficiently in both groups after operation (P < .0001). There was no significant difference between the 2 groups in terms of early postoperative VCA, VCA measured at final follow-up, or loss of correction in VCA. At the last follow-up, PBH was statistically significantly better preserved in group B (P=.0424). There was no difference between the 2 groups in terms of operation time and the number of intraoperative fluoroscopies. Implant failure was observed in 1 patient in group A. CONCLUSION: This study has revealed that using a long, thick pedicle screw placed in the fractured vertebra can better preserve the PBH at the final follow-up. No correlation was found between the size of the intermediate screw and the preservation of the correction in the postoperative vertebral heights and VCA during the follow-up. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Prevalence, Features, and Predictive Factors of Spontaneous Spinal Arthrodesis in Posttraumatic Thoracolumbar Kyphosis.

OBJECTIVE: Spontaneous spinal arthrodesis (SSA) is a phenomenon of spontaneous fusion, and SSA is not rare in posttraumatic thoracolumbar kyphosis (PTK). However, few reports have focused on SSA in patients with PTK. The objective of this study was to investigate the prevalence, features, and predictive factors of SSA in patients with PTK. METHODS: In this retrospective study, 70 patients with PTK were included. Data on the clinical and radiologic parameters were obtained and evaluated. According to whether there was SSA or not, patients were divided into an SSA group (n = 45) or a non-SSA group (n = 25). A binary logistic regression analysis was used to identify the predictive factors for SSA. RESULTS: The incidence of SSA in PTK was 64%. Among 45 patients with PTK with SSA, SSA was present as a solid bridging anterior osteophyte along the vertebral bodies in 11 patients, posterior contiguous bony growth through the facet joints bilaterally in 13 patients, bony formation in both anterior and posterior elements in 18 patients, and direct contiguous bony formation from the injured vertebral body to the adjacent one in 3 patients. Patients with longer disease duration, larger local Cobb angle, and anterior wall height loss (AWHL) ratio of injured vertebral body, and less kyphosis flexibility index were significantly more likely to develop SSA. The parameter of AWHL remained significant in binary logistic regression analysis. CONCLUSIONS: SSA in PTK was common, and the SSA sign presented in various patterns, which might have implications for surgical decisions. AWHL was the independent predictor for SSA.

Finite element study on three osteotomy methods for treating thoracolumbar osteoporotic fracture vertebral collapse complicated with neurological dysfunction.

BACKGROUND: Surgical methods for patients with osteoporotic fracture vertebral collapse complicated with neurological dysfunction are still a topic of debate. We designed an improved osteotomy for the treatment of osteoporotic compression fracture patients with neurological dysfunction. Compared with traditional osteotomy methods such as pedicle subtraction osteotomy (PSO) and bone-disc-bone osteotomy (BDBO), the osteotomy range is reduced. Therefore, we use a finite element method to analyze the biomechanical conditions of these three osteotomy methods and provide a mechanical theoretical basis for the surgical treatment of these three osteotomy methods. METHODS: Based on the CT scan of a patient with L1 osteoporotic fracture vertebral collapse and neurological dysfunction, the finite element model was constructed by importing Mimics software, and three different osteotomy models were established. The forces and displacements of internal fixation device, T1-L5 whole segment, T10 vertebral body, and T10/11 intervertebral disc were recorded under different working conditions. RESULTS: The displacement levels of internal fixation device, T1-L5 spine, T10 vertebral body, and T10/11 intervertebral disc in the modified osteotomy group were between BDBO group and PSO group. The stress in BDBO group was concentrated in titanium mesh and its maximum stress was much higher than that in PSO group and modified osteotomy group. The mechanical distribution of T10/11 intervertebral disc showed that the maximum stress distribution of the three osteotomy methods was similar. CONCLUSION: The relatively simple modified osteotomy has certain advantages in stress and displacement. In contrast, the stability of BDBO group was poor, especially in the lumbar intervertebral disc and lumbar body. For this type of osteotomy patients, it is recommended to avoid postoperative flexion so as not to increase the load.

Surgeon reported treatment choices for AO type B and C thoracolumbar fractures without neurological deficits: An expert survey.

INTRODUCTION: Less invasive spine surgery (LISS) has become well-established for thoracolumbar burst fractures without neurological deficits. However, notable controversy persists regarding the adequacy of LISS for more unstable AO type B and C injuries, as it does not allow for formal open fusion. MATERIALS AND METHODS: In this cross-sectional survey experienced spine surgeons of the Dutch Spine Society were invited to participate (56 participants). They were asked to indicate the most appropriate treatment for AO type B1, B2 (L1: A1 and L1: A3), B3 and C (L1: A4) injuries at level Th12-L1. Taking into account: age, AO N0-N1, or polytrauma. Specific agreement between participants was obtained applying Variation Ratio (VR). RESULTS: A significant level of overall agreement was observed for AO type-B1 injuries with 73.8% of participants opting for percutaneous short-segment fixation (VR 0.775). For AO type-B3 injuries, 79.4% of participants favored percutaneous long-segment fixation (VR 0.794). for AO type-B2 injuries, there was less overall agreement (VR 0.571-0.657). Nonetheless, when considering all AO type-B injuries combined, percutaneous fixation emerged as the most preferred treatment option with substantial agreement (VR 0.871-0.923). Conversely, for AO type-C injuries, there was less agreement among the participants (VI 0.411), 26.5% of them chose additional open spinal fusion. CONCLUSION: For all AO type-B injuries there was substantial agreement to treat these fractures with percutaneous techniques. For AO type-C injuries, the survey results do not support a consensus. Nevertheless, the responses raise important questions about the necessity of spinal fusion for such injuries.

Subject-Specific Geometry of FE Lumbar Spine Models for the Replication of Fracture Locations Using Dynamic Drop Tests.

For traumatic lumbar spine injuries, the mechanisms and influence of anthropometrical variation are not yet fully understood under dynamic loading. Our objective was to evaluate whether geometrically subject-specific explicit finite element (FE) lumbar spine models based on state-of-the-art clinical CT data combined with general material properties from the literature could replicate the experimental responses and the fracture locations via a dynamic drop tower-test setup. The experimental CT datasets from a dynamic drop tower-test setup were used to create anatomical details of four lumbar spine models (T12 to L5). The soft tissues from THUMS v4.1 were integrated by morphing. Each model was simulated with the corresponding loading and boundary conditions from the dynamic lumbar spine tests that produced differing injuries and injury locations. The simulations resulted in force, moment, and kinematic responses that effectively matched the experimental data. The pressure distribution within the models was used to compare the fracture occurrence and location. The spinal levels that sustained vertebral body fracture in the experiment showed higher simulation pressure values in the anterior elements than those in the levels that did not fracture in the reference experiments. Similarly, the spinal levels that sustained posterior element fracture in the experiments showed higher simulation pressure values in the vertebral posterior structures compared to those in the levels that did not sustain fracture. Our study showed that the incorporation of the spinal geometry and orientation could be used to replicate the fracture type and location under dynamic loading. Our results provided an understanding of the lumbar injury mechanisms and knowledge on the load thresholds that could be used for injury prediction with explicit FE lumbar spine models.

Implementation of Robotic Exoscope in Minimally Invasive Corpectomy at Thoracolumbar Junction for the Treatment of Traumatic Spinal Cord Compression.

The development and diffusion of minimally invasive (MI) approaches have coincided with improvements in magnification systems. The exoscope will probably open a new era in new technologies in spinal surgery. This study reports a retrospective series of 19 thoracolumbar (T11-L2) burst fractures with anterior column failure and cord compression, treated with MI corpectomy and spinal decompression assisted by a three-dimensional high-definition exoscope (Video 1). Exclusion criteria were pathologic or osteoporotic fractures, multilevel fractures, and previous surgery at the site of the fracture. Three key indicators were recorded: surgical time, blood loss, and intraoperative complications. A questionnaire was administered to assess the users' exoscope experience with ergonomics, preparation, magnification, image definition, illumination, and user-friendliness, compared with the operative microscope. To the best of our knowledge, this is the first study reporting on exoscope-assisted MI corpectomy. This procedure permitted low blood loss and less surgical time without intraoperative complications. The exoscope offers clear advantages in terms of ergonomics, definition, and user-friendliness. Moreover, it is a suitable instrument for training and education, providing an opportunity for better interaction with other members of the surgical staff.

Vertebral fracture severity assessment on anteroposterior radiographs with a new semi-quantitative technique.

We developed a new tool to assess the severity of osteoporotic vertebral fracture using radiographs of the spine. Our technique can be used in patient care by helping to stratify patients with osteoporotic vertebral fractures into appropriate treatment pathways. It can also be used for research purposes. PURPOSE: The aim of our study was to propose a semi-quantitative (SQ) grading scheme for osteoporotic vertebral fracture (OVF) on anteroposterior (AP) radiographs. METHODS: On AP radiographs, the vertebrae are divided into right and left halves, which are graded (A) vertical rectangle, (B) square, (C) traverse rectangle, and (D) trapezoid; whole vertebrae are graded (E) transverse band or (F) bow-tie. Type A and B were compared with normal and Genant SQ grade 1 OVF, Type C and D with grade 2 OVF, and Type E and F with grade 3 OVF. Spine AP radiographs and lateral radiographs of 50 females were assessed by AP radiographs SQ grading. After training, an experienced board-certified radiologist and a radiology trainee assessed the 50 AP radiographs. RESULTS: The height-to-width ratio of the half vertebrae varied 1.32-1.48. On lateral radiographs, 84 vertebrae of the 50 patients had OVFs (38 grade 1, 24 grade 2, and 22 grade 3). On AP radiographs, the radiologist correctly assigned 84.2%, 91.7%, and 77.2% and the trainee correctly assigned 68.4%, 79.2%, and 81.8% of grade 1, 2, and 3 OVFs, respectively. Compared with lateral radiographs, the radiologist had a weighted Kappa of 0.944 including normal vertebrae and 0.883 not including normal vertebrae, while the corresponding Kappa values for the trainee were 0.891 and 0.830, respectively. CONCLUSION: We propose a new semi-quantitative grading system for vertebral fracture severity assessment on AP spine radiographs.