The biomechanics of long versus short fixation for thoracolumbar spine fractures

The effectiveness of short hybrid stabilization with sublaminar bands and transpedicular screws in the treatment of thoracolumbar spine fractures

BACKGROUND

Long constructs have always been widely recommended for the treatment of thoracolumbar fractures, due to their biomechanical stability and minimal postoperative loss of correction. However, short constructs have significant advantages, since they enable for better postoperative lumbar mobility and reduce the risk of adjacent segment degeneration. The purpose of this study is to evaluate the safety and efficacy of hybrid screw/sublaminar bands short constructs, used for the treatment of thoracolumbar fractures.

METHODS

From June 2015 until November 2017, 20 consecutive patients (14 male, 6 female) with an average age of 52.9 years, exhibiting at least one traumatic fracture in the thoracolumbar region, were treated with hybrid screw/sublaminar bands short constructs. The data for analysis included: duration of the intervention, intraoperative blood loss, complications, and clinical and radiographic postoperative results, compared with the standard for thoracolumbar fixation.

RESULTS

The use of this type of construct allowed for simple reduction, stabilization of the fractures, and restoration of the physiological spine curvatures. During the postoperative period none of the patients had neurological worsening. 18 out of 20 patients were followed up for two years. One patient sustained implant failure six months after surgery and underwent a surgical implant revision with traditional long fixation. After two years, stability and fusion were obtained in all patients, along with correct spine alignment.

CONCLUSIONS

Hybrid screw/sublaminar bands short constructs seem to be effective in the treatment of thoracolumbar fractures, providing the same clinical results of the state-of-the-art pedicular screw/rod long constructs, but in addition they allow for better postoperative lumbar mobility and subsequently reduce the risk of adjacent segments degeneration. The results of this clinical case series might support the initiation of prospective randomized trials with more patients, a longer follow-up period, and control groups.

Operative results of AO A3 and A4 traumatic injuries in the thoracic and lumbar spine. A multicenter surveillance study of 4230 patients from the German Spine Registry (DWG-Register)

BACKGROUND

The diagnosis, classification and treatment of thoracolumbar burst fractures, continue to be controversial. Surgery is generally the preferred treatment for unstable fractures while stable fractures are managed conservatively. This study aims to describe surgical procedures, outcomes, complications, demography, clinical features and differences between A3 and A4 fractures (AO classification) of the thoracolumbar region. A subgroup of patients <91 years with osteoporotic fractures is included and analyzed.

METHODS

Analysis of data from the DWG-Register German spine registry on operative treatment for thoracolumbar AO A3 and A4 fractures out of 170 departments from January 2017 to May 2021. The evaluated variables included age, gender, surgical approach (posterior, anterior combined), and re-operation.

RESULTS

In total, 4230 AO A3 and A4 thoracolumbar fractures were identified in the registry; 2898 A3 (group 1) and 1332 A4 (group 2). The preoperative ASIA-impairment scale score in group 1 was significantly different compared with group 2 (P=0.02). Surgical procedures such as decompression/stabilization with rod-screw system cemented/non-cemented, as well as an anterior approach, were statistically significant between the groups. Odds ratio was calculated for variables that could be influenced for the type of fracture (A3 or A4): decompression 4.89, OR time >2 hours 48.22, osteoporosis 6.46 and posterior access 9.85.

CONCLUSIONS

This study provides multicenter results from a huge number of surgically treated AO A3 and A4 fractures. Anterior approaches are more often used in A4 type fractures, probably because of its inherent instability related to burst fractures, surprisingly, not associated with the occurrence of added perioperative complications. Nevertheless, A3 type fractures are presented with worse ASIA Impairment-Scale at admission, in comparison with A4 type fractures of the thoracolumbar region.

Clinic choice of long or short segment pedicle screw-rod fixation in the treatment of thoracolumbar burst fracture: From scan data to numerical study

Based on computerized tomography scanning images of human lumbar vertebrae, finite element (FE) analysis is performed to predict the stress of pedicle screws, rods, and fractured vertebra as well as the displacement of fractured vertebra after internal fixation treatment of thoracolumbar burst fracture. A three-dimensional FE model of L1-L5 lumbar vertebrae with L3 burst fracture has been established and four fixation methods, namely, short segment cross- and trans-injured vertebrae, long segment cross- and trans-injured vertebrae fixations, have been adopted to perform posterior pedicle fixation. The stress distributions of the screws, rods, and fractured vertebra and the total deformation of the fractured vertebra are investigated under six different physiological motions. From the view of the stress on the screw-rod system and the deformation of the fractured vertebral body, the long segment cross-injured vertebra fixation has the best mechanical performance, followed by the long segment trans-injured vertebra fixation, and then the short segment fixation trans-injured vertebra. The short segment fixation cross-injured vertebra performs the worst. Among the six motions, the forward flexion movement has the greatest impact on the screw-rod system and the fractured vertebra. However, the rotation motion greatly affects the stress of the screw in the long segment fixation. This indicates that the longer the fixed segment is, the more susceptible it is to human rotation. Thus, for patients with severe fracture, the long segment cross-injured vertebra is preferred. On the contrary, the short segment trans-injured vertebra fixation is optimal.

Long segment versus short segment stabilization in thoracolumbar spine fracture: A retrospective clinical and radiological analysis

Introduction: Thoracolumbar spine fracture is one of the commonest spinal fractures. The treatment of choice of surgery is still controversial. This is a retrospective analysis of clinical and radiological outcomes of long and short segment stabilization for patients admitted with thoracolumbar fracture in our hospitals. Material and Method: Inclusion criteria included a single level of thoracolumbar fracture, excluding pre-existing deformity or spinal surgery, osteoporosis, and pathological fracture. Clinical parameters included visual analogue scale (VAS), operative time, intraoperative blood loss, and postoperative length of stay. Radiological parameters included wedge angle and anterior and posterior vertebral height ratio. Results: From June 2007 to May 2020, 56 patients (male = 31, female = 25) were recruited. There were 25 patients in the short segment group (open = 11, minimal invasive surgery (MIS) = 14) and 31 patients in the long segment group. Clinically, significantly better VAS at 6 months (1 vs. 1.96; p = 0.041), shorter post-op length of stay (16 days vs. 25 days; p = 0.01), and less blood loss (178 ml vs. 824 ml; p < 0.01) were found in the short segment group. Radiologically, the short segment group showed significantly better wedge angle at immediate (5° vs. 9.23°; p = 0.002) and long-term follow-up (7.41° vs. 11.43°; p = 0.01). Moreover, the short segment group has significantly better post-op anterior and posterior vertebral height ratios. Within the short segment group, the MIS group showed significantly less blood loss (82 ml vs. 303 ml; p < 0.01). However radiological parameters favour the open group. Discussion and Conclusion: For single-level thoracolumbar fracture, both long and short stabilizations were effective in reducing and stabilizing the fracture. However, the short segment group showed significantly superior results. Moreover, a minimally invasive technique in short segment stabilization showed even less blood loss but less optimal radiological results. Therefore, short segment stabilization could be the treatment of choice for traumatic thoracolumbar spine fractures.

Percutaneous cortical bone trajectory screw fixation versus traditional open pedicle screw fixation for type A thoracolumbar fractures without neurological deficit

Retrospective matched-cohort comparative study. Cortical bone trajectory screw (CBT) technique is a new insertion technique in terms of fixation strength and less invasiveness. The purposes of this study were to compare the clinical and radiological outcomes of percutaneous CBT fixation (PCBT) with traditional open posterior pedicle screw fixation (OPPS) technique. Between September 2019 and October 2020, patients undergoing posterior stabilization were matched for age, sex, diagnosis, fractured level, and AO classification. 24 control patients with OPPS were identified and appropriately matched to 24 consecutive patients with PCBT technique. Clinical outcomes and radiographic assessments including vertebral wedge angle (VWA) and sagittal index were recorded and compared between the two groups. Incision length, intraoperative blood loss and hospital stay in the PCBT group were significantly better than the OPPS group (P < 0.05). The VAS scores 5 days after operation for PCBT patients were significantly lower than those for OPPS patients (P = 0.003), but these differences lost significance at last follow-up. There was no significant difference in VWA and sagittal index between OPPS and PCBT group (P > 0.05). While no complications were noted in the PCBT group, there were four cases with complications in the traditional OPPS group. The present study showed that PCBT is a safe and feasible method for the treatment of thoracolumbar fractures without neurological deficits. This new surgical treatment was more minimally invasive, yet yielded equivalent or superior clinical and radiographic outcomes compared to the traditional open pedicle screw fixation surgery.

Long-Segment Versus Short-Segment Pedicle Screw Fixation Including Fractured Vertebrae for the Management of Unstable Thoracolumbar Burst Fractures

Background For the treatment of unstable thoracolumbar fractures, this study compared the results of short-segment fixation with fracture level inclusion (SSFIFL) with long-segment pedicle fixation (LSPF). Methodology In this prospective case series study conducted from January 2015 to January 2019, 80 patients with partial spinal cord lesions were investigated. For the comparison, two groups of 40 patients each were chosen and treated with SSFIFL and LSPF. The outcomes were measured using pre and postoperative radiological parameters and clinical parameters. The radiographic variables included the kyphotic angle with loss of correction, kyphotic deformation, and the Beck index. Mean blood loss, operative time, and cost-effectiveness were also examined for clinical indicators such as the American Spinal Injury Association Impairment Scale, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI). Results There were no substantial variations between the groups regarding age or gender, trauma etiology, fracture level, or fracture pattern. Between the two categories, there appeared to be no notable change in radiological indicators such as kyphotic angle, kyphotic deformation, and Beck index at the end of follow-up (p = 0.120, 0.360, and 0.776, respectively). Both groups had similar neurological outcomes (p = 0.781). In terms of ODI and VAS, statistically, there was no discernible difference (p = 0.567 and 0.161, respectively). In this study, however, there was less surgical time, blood loss, and implant cost (p = 0.05). Conclusions When fracture level is included in a short-segment fixation, the radiological and clinical results are comparable to long-segment posterior fixation. Ultimately, this treatment has proven to be not only a motion segment-saving procedure but also cost-effective.

Surgical management of thoracolumbar junction fractures: An evidence-based algorithm

Background

The management of thoracolumbar junction (TLJ) fractures, involving the restoring anatomical stability and biomechanics properties, still remains a challenge for neurosurgeons.Despite the high frequency of these injuries, specific treatment guidelines, set on biomechanical properties, have not yet been assumed. The present study is meant to propose an evidence-based treatment algorithm. The primary aim for the protocol validation was the assessment of postoperative neurological recovery. The secondary objectives concerned the evaluation of residual deformity and rate of hardware failure. Technical nuances of surgical approaches and drawbacks were further discussed.

Methods

Clinical and biomechanical data of patients harboring a single TLJ fracture, surgically managed between 2015 and 2020, were collected. Patients' cohorts were ranked into 4 groups according to Magerl's Type, McCormack Score, Vaccaro PLC point, Canal encroachment, and Farcy Sagittal Index. The outcome measures were the early/late Benzel-Larson Grade and postoperative kyphosis degree to estimate neurological status and residual deformity, respectively.

Results

32 patients were retrieved, 7, 9, 8, and 8 included within group 1, 2, 3, and 4, respectively. Overall neurological outcomes significantly improved for all patients at every follow-up stage (p ​< ​0.0001). Surgeries gained a complete restoration of post-traumatic kyphosis in the entire cohort (p ​< ​0.0001), except for group 4 which experienced a later worsening of residual deformity.

Conclusions

The choice of the most appropriate surgical approach for TLJ fractures is dictated by morphological and biomechanical characteristics of fracture and the grade of neurological involvement. The proposed surgical management protocol was reliable and effective, although further validations are needed.

Short-segment fixation and transpedicular bone grafting for the treatment of thoracolumbar spine fracture

Purpose

Thoracolumbar fracture is one of the most common fractures of spine. And short-segment posterior fixation including the fractured vertebra (SSPFI) is usually used for the surgical treatment of it. However, the outcomes of SSPFI for different types of thoracolumbar fractures are not clear, and whether it is necessary to perform transpedicular bone grafting is still controversial. This study was conducted to determine the clinical efficacy of SSPFI for the treatment of different types of single-level thoracolumbar fracture, and make clear what kind of fractures need transpedicular bone grafting during the surgery.

Methods

Patients with single-level thoracolumbar fracture undergoing SSPFI surgery between January 2013 and June 2020 were included in this study. The operative duration, intraoperative blood loss, anterior vertebral height ratio (AVHR) and anterior vertebral height compressive ratio (AVHC) of the fractured vertebra, local kyphotic Cobb angle (LKA), vertebral wedge angle (VWA) and correction loss during follow up period were recorded. Outcomes between unilateral and bilateral pedicle screw fixation for fractured vertebra, between SSPFI with and without transpedicular bone grafting (TBG), and among different compressive degrees of fractured vertebrae were compared, respectively.

Results

A total of 161 patients were included in this study. All the patients were followed up, and the mean follow-upped duration was 25.2 ± 3.1 months (6-52 months). At the final follow-up, the AVHR was greater, and the LKA and VWA were smaller in patients with bilateral fixation (6-screw fixation) than those with unilateral fixation (5-screw fixation) of AO type A3/A4 fractures (P < 0.001). The correction loss of AVHR, LKA and VWA in fractured vertebra were significantly great when preoperative AVHC was >50% (P < 0.05). For patients with AVHC >50%, the correction loss in patients with TBG were less than those without TBG at the final follow-up (P < 0.05).

Conclusions

SSPFI using bilateral fixation was more effective than unilateral fixation in maintaining the fractured vertebral height for AO type A3/A4 fractures. For patients with AVHC >50%, the loss of correction was more obvious and it can be decreased by transpedicular bone grafting.

Cross-link augmentation enhances CFR-PEEK short fixation in lumbar metastasis stabilization

Introduction: Spinal stability plays a crucial role in the success of the surgical treatment of lumbar vertebral metastasis and, in current practice, less invasive approaches such as short constructs have been considered. Concurrently, carbon fiber-reinforced (CFR) poly-ether-ether-ketone (PEEK) fixation devices are expanding in oncologic spinal surgery thanks to their radiotransparency and valid mechanical properties. This study attempts to provide an exhaustive biomechanical comparison of different CFR-PEEK surgical stabilizations through a highly reproducible experimental setup. Methods: A Sawbones biomimetic phantom (T12-S1) was tested in flexion, extension, lateral bending, and axial rotation. An hemisome lesion on L3 vertebral body was mimicked and different pedicle screw posterior fixations were realized with implants from CarboFix Orthopedics Ltd: a long construct involving two spinal levels above and below the lesion, and a short construct involving only the levels adjacent to L3, with and without the addition of a transverse rod-rod cross-link; to provide additional insights on its long-term applicability, the event of a pedicle screw loosening was also accounted. Results: Short construct reduced the overloading onset caused by long stabilization. Particularly, the segmental motion contribution less deviated from the physiologic pattern and also the long-chain stiffness was reduced with respect to the prevalent long construct. The use of the cross-link enhanced the short stabilization by making it significantly stiffer in lateral bending and axial rotation, and by limiting mobiliza-tion in case of pedicle screw loosening. Discussion: The present study proved in vitro the biomechanical benefits of cross-link augmentation in short CFR-PEEK fixation, demonstrating it to be a potential alternative to standard long fixation in the surgical management of lumbar metastasis.

Vertebrae at the thoracolumbar junction: A quantitative assessment using CT scans

The thoracolumbar junction is often associated with traumatic injuries, due to its biomechanical instability. Reasons for this instability are currently still under debate; however, contributing factors such as the rapid change in spinal curvature and facet orientation from the thoracic to lumbar transition have been implicated. Normally, the superior facet orientation in the thoracic region is angled in a coronal plane, whereas vertebrae in the lumbar region have facets angled in the sagittal plane. Distinguishing between thoracic, lumbar, and transitional vertebrae at the thoracolumbar junction based on articular facet angles, using quantitative methods on CT scans has, to the authors' knowledge, not yet been reported in the literature. Therefore, this study aimed to evaluate whether quantitative measurements can be clinically applied and used to differentiate vertebrae at the thoracolumbar junction using CT scans and, additionally, to record possible cases of congenital defects or variations observed in the spine. A sample (n = 173) of CT scans representative of the Windhoek population in Namibia was retrospectively assessed using radio-imaging software. Measurements of the angle formed by the superior facets of the vertebrae at the thoracolumbar junction (T11-L1) were recorded. Based on the results of this study, quantitative morphometry of the superior facet of vertebrae can differentiate between thoracic, lumbar,. and transitional vertebrae at the thoracolumbar junction. All individuals with identified thoracolumbar transitional vertebrae (TLTV) in this sample had at least one other congenital anomaly of the spine.

Risk Factors for Postoperative Loss of Correction in Thoracolumbar Injuries Caused by High-Energy Trauma Treated via Percutaneous Posterior Stabilization without Bone Fusion

Background and Objectives: Percutaneous pedicle screws were first introduced in 2001, soon becoming the cornerstone of minimally invasive spinal stabilization. Use of the procedure allowed adequate reduction and stabilization of spinal injuries, even in severely injured patients. This decreased bleeding and shortened surgical time, thereby optimizing outcomes; however, postoperative correction loss and kyphosis still occurred in some cases. Thus, we investigated cases of percutaneous posterior fixation for thoracolumbar injury and examined the factors affecting the loss of correction. Materials and Methods: Sixty-seven patients who had undergone percutaneous posterior fixation for thoracolumbar injury (AO classifications A3, A4, B, and C) between 2009 and 2016 were included. Patients with a local kyphosis angle difference ≥10° on computed tomography at the postoperative follow-up (over 12 months after surgery) or those requiring additional surgery for interbody fusion were included in the correction loss group (n = 23); the no-loss group (n = 44) served as the control. The degree of injury (injury level, AO classification, load-sharing score, local kyphosis angle, cuneiform deformity angle, and cranial and caudal disc injury) and surgical content (number of fixed intervertebral vertebrae, type of screw used, presence/absence of screw insertion into the injured vertebrae, and presence/absence of vertebral formation) were evaluated as factors of correctional loss and compared between the two groups. Results: Comparison between each group revealed that differences in the wedge-shaped deformation angle, load-sharing score, degree of cranial disc damage, AO classification at the time of injury, and use of polyaxial screws were statistically significant. Logistic regression analysis showed that the differences in wedge-shaped deformation angle, AO classification, and cranial disc injury were statistically significant; no other factors with statistically significant differences were found. Conclusion: Correction loss was seen in cases with damage to the cranial intervertebral disc as well as the vertebral body.

Surgical fixation of pathologic and traumatic spinal fractures using single position surgery technique in lateral decubitus position

STUDY DESIGN

Retrospective Case Series.

OBJECTIVES

This study aims to determine complications, readmission, and revision surgery rates in patients undergoing single position surgery (SPS) for surgical treatment of traumatic and pathologic thoracolumbar fractures.

METHODS

A multi-center review of patients who underwent SPS in the lateral decubitus position (LSPS) for surgical management of traumatic or pathologic thoracolumbar fractures between January 2016 and May 2020 was conducted. Operative time, estimated blood loss (EBL), intraoperative complications, postoperative complications, readmissions, and revision surgeries were collected.

RESULTS

A total of 12 patients with a mean age of 45 years (66.67% male) were included. The majority of patients underwent operative treatment for acute thoracolumbar trauma (66.67%) with a mean injury severity score (ISS) of 16.71. Mean operative time was 175.5 min, mean EBL of 816.67 cc. Five patients experienced a complication, two of which required revision surgery for additional decompression during the initial admission. All ambulatory patients were mobilized on postoperative day 1. The mean hospital length of stay (LOS) was 9.67 days.

CONCLUSION

The results of this case series supports LSPS as a feasible alternative to the traditional combined anterior-posterior approach for surgical treatment of pathologic and thoracolumbar fractures. These results are similar to reductions in operative time, EBL, and LOS seen in the elective spine literature with LSPS.

LEVEL OF EVIDENCE

IV.

Efficacy and Radiographic Analysis of Minimally Invasive Posterior Mono-Axial Pedicle Screw Fixation in Treating Thoracolumbar Burst Fractures

Background: The purpose of this study was to evaluate the effectiveness of minimally invasive posterior mono-axial pedicle screws fixation in the treatment of thoracolumbar burst fractures. Methods: In the present study, we analyzed 98 patients retrospectively who had thoracolumbar burst fractures without a neurological deficit. Patients were divided into two groups: mono-axial pedicle screw fixation group (n = 52) and poly-axial pedicle screw fixation group (n = 46). We collected clinical data (visual analog scale (VAS) score for back pain) and included radiographic measurements. Results: Sagittal index was significantly improved at postop and last follow-up in the mono group and the poly group. The mono group was better for reducing and maintaining anterior vertebral height. For the mono group, the mean postoperative regional kyphosis correction rate was 62.31%, and correction loss was 14.18% in late follow-up. For the poly group, the mean postoperative regional kyphosis correction rate was 52.17%, and correction loss was 33.42% in late follow-up. The mono-axial pedicle screw group had a good correction rate and reduced the risks of correction loss. The mean VAS scores for back pain improved by 2.4/2.5 and 3.8/4.2 for the mono and poly groups, respectively. There was no significant difference between groups. Conclusions: The mono-axial pedicle screw fixation was better for reducing and maintaining anterior vertebral height and regional kyphosis. Therefore, the mono-axial pedicle screw is a better optional instrumentation to treat thoracolumbar vertebral fractures.

SHORT ARTHRODESIS IS AS EFFECTIVE AS LONG ARTHRODESIS FOR THE TREATMENT OF TYPE B THORACOLUMBAR SPINE FRACTURES

ABSTRACT Objective: Thoracolumbar spine trauma is a world wide health concern that especially affects males of working age, being associated with an elevated morbidity. AO SPINE Type B fractures are unstable and require surgical stabilization. However, the decision between short or long fixation remains controversial. The objective of this study is to analyze the neurological, orthopedic and functional outcomes in patients with Type B spine fractures who have undergone short and long segment posterior arthrodesis. Methods: A prospective cohort study was performed at the Neurosurgery Department of Hospital Cristo Redentor from January 1, 2013 to December 31, 2018. Patients with spine fractures classified as AO SPINE Type B in the thoracic or thoracolumbar segments were eligible for the study. The variables analyzed included demographic data, information about the trauma, neurological status, the treatment performed, and the outcome. Results: A total of 31 patients were included in the study. The majority were Caucasian males with a mean age of 42.6(±15.6), and the main cause of the spine trauma was falling from height (N=18; 56.2%). Fifteen patients (48.3%) had subtype B1 fractures and 16 (51.6%) had subtype B2 fractures. Eleven (35.4%) patients were submitted to short arthrodesis and 20 (64.5%) were submitted to long arthrodesis. There was no statistical difference between groups in terms of neurological, orthopedic and functional outcomes. Conclusions: There is no difference in outcomes between short or long constructs for patients with type B single fracture in the thoracic, thoracolumbar and lumbar spine segments. Level of evidence III; Therapeutic Studies – Investigation of treatment results.

Investigation of Preoperative Traction Followed by Percutaneous Kyphoplasty Combined with Percutaneous Cement Discoplasty for the Treatment of Severe Thoracolumbar Osteoporotic Vertebral Compression Fractures

Objective

To evaluate the feasibility, clinical efficacy and imaging results of preoperative traction (PT) followed by percutaneous kyphoplasty (PKP) combined with percutaneous cement discoplasty (PCD) for treating severe thoracolumbar osteoporotic vertebral compression fractures (OVCFs).

Methods

A total of 13 patients with severe thoracolumbar OVCFs treated by PT followed by PKP combined with PCD were enrolled. General information, PT time, operation time, postoperative hospital stay, perioperative complications, visual analog scale (VAS) score, Oswestry disability index (ODI) score, local kyphosis angle, intervertebral angle (IVA), anterior vertebral height (AVH) and posterior vertebral height (PVH) were recorded.

Results

The average VAS score at admission was 7.4±3.5, decreased to 4.3±1.7 after PT and 2.3±0.7 three days after operation, and 1.5±0.9 at last follow-up. The average ODI score was 73.7±21.4 before operation, decreased to 26.6±9.3 three days after operation and 13.7±7.1 at last follow-up. Compared to VAS and ODI scores at admission, these at the third day after operation and last follow-up were significantly different. At admission, the IVA was 3.4°±6.8°, the disc height was 5.7±1.2mm, the AVH was 10.7±3.2mm, and the PVH was 25.7±4.2 mm, which, after PT, changed to 8.1°±7.3°, 8.6±2.6mm, 18.5±2.8mm, and 26.2±7.1mm, respectively, and the differences were significant. The average kyphotic angle was 43.4°±17.8° at admission, and decreased to 26.3°±6.7° after PT, 17.5°±8.4° three days after operation and 19.1°±10.3° at last follow-up, and the differences were significant.

Conclusion

PT followed by PKP combined with PCD for the treatment of severe thoracolumbar OVCFs was an effective and simple procedure with satisfactory short-term clinical outcomes by relieving pain and improving kyphosis.

Minimally Invasive Short-Segment Anteroposterior Surgery for Thoracolumbar Osteoporotic Fractures with Canal Compromise: A Prospective Study with a Minimum 2-Year Follow-up

Study Design

A prospective study with a minimum follow-up of 24 months.

Purpose

This study aimed to evaluate the results of minimally invasive anteroposterior surgery for osteoporotic vertebral fractures (OVFs) associated with bony spinal canal compromise in elderly patients.

Overview of Literature

There is a recent increase in the incidence of osteoporosis with OVFs, causing an increasing burden on medical systems.

Methods

The study included 47 patients, of whom 45 completed a minimum of 24-month follow-up. The inclusion criteria were OVF types 3 and 4 according to the osteoporotic fracture classification in patients aged ≥65 years with bony stenosis. The surgical management consisted of anterior corpectomy and decompression using a thoracoscopic or mini-laparotomy approach, together with posterior percutaneous cement-augmented short-segment fixation. Self-reported outcome measures included Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) in the preoperative phase and regular follow-up at a minimum of 24 months. Radiological measures included segmental lordosis, dual-energy X-ray absorptiometry for osteoporosis assessment, and radiological fracture healing.

Results

There were 33 patients with lumbar fracture and 12 patients with thoracic fracture. Thirteen patients had preoperative neurological deficits. The mean age was 77.4±8.3 years. The mean preoperative VAS score was 8.12±1.5, and the mean ODI score was 24.4±8.2. The mean preoperative sagittal Cobb angle was 6.3°±4.2° kyphosis. The mean operative time was 220.3±55.5 minutes, with a mean blood loss of 360.75±200.6 mL. After a mean follow-up of 32.6±6.4 months, the mean VAS significantly improved to 2.3, and the ODI to 12. Only three patients still had a partial neurological deficit. The mean final sagittal Cobb angle was significantly better, with 12.5°±4.3° of lordosis.

Conclusions

Short-segment percutaneous fixation with cement augmentation combined with minimally invasive anterior decompression and corpectomy is a less invasive and safe approach in elderly patients with OVF and canal compromise.

Outcomes of Thoracolumbar Fracture-Dislocation Managed by Short-Segment and Long-Segment Posterior Fixation: A Single-Center Retrospective Study

BACKGROUND

Long-segment posterior fixation has been used as a mainstay treatment of spine fracture-dislocations. Studies using short-segment posterior fixation in cases of thoracolumbar fracture-dislocation are limited. We describe our experience of 26 patients with thoracolumbar fracture-dislocation treated by short-segment or long-segment posterior spinal fixation and fusion.

METHODS

This is a single-center retrospective study of 26 patients with thoracolumbar fracture-dislocation treated by long-segment (group 1, n = 12) and short-segment posterior instrumentation (group 2, n = 14). Clinical (visual analog scale [VAS], Oswestry Disability Index [ODI]), neurological (American Spinal Injury Association [ASIA] scale), radiological (kyphotic angle, translational percentage, and displacement angle), and surgical (blood loss, operative time) outcomes and complications were recorded with each method. The mean follow-up period was 8.64 months (6-20 months).

RESULTS

The mean duration of surgery was 3.92 ± 0.67 hours in group 1 and 3.21 ± 0.54 hours in group 2, and mean blood loss was 583.33 ± 111.5 mL and 478.6 ±112.2 mL in groups 1 and 2, respectively (P < .05). There was no radiologically visible pseudarthrosis, implant failure, or screw breakage in either group at follow up with no statistically significant difference between the 2 groups with regard to the radiological outcome (P > .05). Two patients in group 1 and 6 patients in group 2 improved after surgery at least 1 ASIA grade. VAS and ODI improved in both groups at the final follow up.

CONCLUSIONS

Short-segment fixation can be used for treating fracture-dislocation patients, as it results in less blood loss, decreased intraoperative time, and saves fusion segments with similar radiological and clinical outcomes as long-segment fixation.

LEVEL OF EVIDENCE

3.

Long-term follow-up results in patients with thoracolumbar unstable burst fracture treated with temporary posterior instrumentation without fusion and implant removal surgery: Follow-up results for at least 10 years

Segmental fusion is not necessarily needed in treatment of thoracolumbar unstable burst fracture requiring surgery. Our objective was to report the results of follow-up for at least 10 years in patients with thoracolumbar unstable burst fracture requiring surgery in which fractured segment was healed following temporary posterior instrumentation without fusion, and in whom implants were subsequently removed.Retrospective Cohort Study.Nineteen patients in whom union of fractured vertebra was observed following surgery and in whom implants were removed within an average 12.2 months, and who could be followed up for at least 10 years, were enrolled.At the last follow-up, we evaluated the segmental motions, anterior body height ratio, progress of further kyphotic deformity, Oswestry Disability Index, Rolland Morris Disability Questionnaire and Short Form 36.Results: The follow-up period after implant removal surgery was 151 months on average. The local kyphotic angle was 26.89 ± 6.08 degrees at the time of injury and 10.11 ± 2.22 degrees at the last follow-up. The anterior body height ratio was 0.54 ± 0.16 at the time of injury and 0.89 ± 0.05 at the last follow-up. Thus, the fractured vertebra was significantly reduced after surgery and maintained till last follow-up. The segmental motion was 9.84 ± 3.03, Oswestry Disability Index was 7.95 ± 7.38, Rolland Morris Disability Questionnaire was 2.17 ± 2.67, short form 36 Physical Component Score was 77.50 ± 16.61, and short form 36 Mental Component Score was 79.21 ± 13.32 at last follow-up.We conducted at least 10-year follow-up and found that temporary posterior instrumentation without fusion should be considered one of the useful alternative treatments for thoracolumbar unstable burst fracture in place of the traditional posterior instrumentation and fusion.

Early versus delayed corpectomy in thoracic and lumbar spine trauma. A long-term clinical and radiological retrospective study

AND BACKGROUND DATA

Many authors have demonstrated the necessity of reconstruction of the anterior column in spinal trauma with vertebral body collapse or nonunion. There is no publication comparing the result depending on the time between trauma and anterior reconstruction of the vertebral body.

OBJECTIVE

To compare long-term clinical and radiological results between early and late anterior vertebral body reconstruction with expandable cages in patients with thoracic and lumbar spine trauma.

HYPOTHESIS

An early anterior reconstruction of thoracolumbar fractures provides better clinical and radiological outcomes than a delayed one.

MATERIALS AND METHODS

A retrospective clinical study was carried out with 44 consecutive patients with injuries of the thoracic and lumbar spine treated operatively with combined posterior stabilization and anterior reconstruction with an expandable implant for vertebral body replacement. All patients were evaluated with EOS full-spine radiograph and CT-scan. The mean follow-up was 5.1 years. Clinical result was evaluated with ODI, SF12, VAS back pain, return to work and sport. Radiological result was evaluated with regional kyphosis angle (RKA) evolution, fusion rate and sagittal alignment. In Group A, twenty-nine patients underwent an early anterior reconstruction within 3 weeks after trauma. The indication of vertebral body reconstruction was placed after post-operative CT-scan for a Mc Cormack score≥7. In Group B, fifteen patients underwent a late anterior reconstruction after diagnosis of nonunion by the combination of pain and CT-scan after 1 year.

RESULTS

Clinical scores and scales were significantly better for patients operated early in Group A. Return to work and activities were significantly more important in Group A too. The mean RKA correction with posterior reduction was 9.3°. The secondary anterior approach permit to reduce 2.9° more. At last follow-up, the loss of reduction was 4.3°. There was no significant difference between groups for those results. No difference in fusion rate was observed between groups. There was no significant difference between groups in the sagittal alignment excepted for SVA that was higher for Group B while remaining under a normal value of 50mm.

CONCLUSION

Early anterior vertebral body reconstruction for fractures gives better clinical results than delayed reconstruction for patients with diagnosis of nonunion in patients with thoracic and lumbar spine trauma. Moreover, the shorter the time from trauma to operation, the better the sagittal reduction of kyphosis. The use of expandable titanium cage is a good way to perform and maintain this reduction.

LEVEL OF EVIDENCE

IV, retrospective study.

Surgical management of burst fractures in children and adolescents: A Multicentre Retrospective Study

BACKGROUND

Spinal fractures are rare in children, in whom they contribute only 2% to 5% of all traumatic spinal injuries. The management of burst fractures is well standardised in adults but remains controversial in paediatric patients, due to specific growth-related considerations. The objective of this study was to assess the clinical and radiographic outcomes of surgical management in a multicentre cohort of paediatric patients with burst fractures, in order to devise an optimal therapeutic strategy.

HYPOTHESIS

A therapeutic strategy for burst fractures in children and adolescents can be devised based on data from a patient cohort and on previously published information.

MATERIAL AND METHODS

Patients younger than 18 years who were managed surgically for one or more burst fractures (Magerl A3) were included in this retrospective multicentre study. Clinical, radiographic, and surgical data were collected before surgery, within 3 months after surgery, and 2 years after surgery. The primary surgical approach was posterior in all patients. Computed tomography (CT) was performed post-operatively to assess the extent of anterior bone loss in order to determine whether anterior fusion was required. The 26 included patients had a mean age of 15±1 years. The thoraco-lumbar spine was involved in 15 (57%) patients. Surgery consisted in correction by instrumentation and posterior fusion only in 14 patients and in posterior correction with anterior fusion in 12 patients. In 10 (38%) patients, the instrumentation extended one vertebra above and one vertebra below the fractured vertebra.

RESULTS

Significant correction of the vertebral kyphosis was achieved (17°±11° before vs. 4°±2° after surgery, p=0.001). Anterior and posterior vertebral heights were significantly increased (15±3mm vs. 20±3mm, p=0.01 and 23±4mm vs. 26±4mm, p=0.04, respectively).

DISCUSSION

The decision to perform surgery rests on the degree of kyphosis and presence of instability. Anterior bone grafting can be added if the instrumentation is short or a bone defect persists after posterior correction. Correction of the local kyphosis is important to prevent sagittal malalignment with its adverse functional consequences in adulthood. Neural decompression must be performed in patients with neurological deficits.

LEVEL OF EVIDENCE

IV.

Does Combined Anterior-Posterior Approach Improve Outcomes Compared with Posterioronly Approach in Traumatic Thoracolumbar Burst Fractures?: A Systematic Review

The aim of this systematic review was to evaluate the surgical, radiological, and functional outcomes of posterior-only versus combined anterior-posterior approaches in patients with traumatic thoracolumbar burst fractures. The ideal approach (anterior-only, posterior-only, or combined anterior-posterior) for the surgical management of thoracolumbar burst fracture remains controversial, with each approach having its advantages and disadvantages. A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed (registration no., CRD42018115120). The authors reviewed comparative studies evaluating posterior-only approach compared with combined anterior-posterior approaches with respect to clinical, surgical, radiographic, and functional outcome measures. Five retrospective cohort studies were included. Postoperative neurological deterioration was not reported in either group. Operative time, estimated blood loss, and postoperative length of stay were increased among patients in the combined anterior-posterior group in one study and equivalent between groups in another study. No significant difference was observed between the two approaches with regards to long-term postoperative Cobb angle (mean difference, -0.2; 95% confidence interval, -5.2 to 4.8; p =0.936). Moreover, no significant difference in functional patient outcomes was observed in the 36item Short-Form Health Survey, Visual Analog Scale, and return-to-work rates between the two groups. The available evidence does not indicate improved clinical, radiologic (including kyphotic deformity), and functional outcomes in the combined anterior-posterior and posterior-only approaches in the management of traumatic thoracolumbar burst fractures. Further studies are required to ascertain if a subset of patients will benefit from a combined anterior-posterior approach.

Current status of short segment fixation in thoracolumbar spine injuries

Short segment fixation aims to restore spinal stability and alignment in thoracolumbar spine injuries while preserving spinal motion by decreasing the levels of spine involved in fixation. In its simplest form it applies to fixation one level above and one level below the fractured vertebra. It has proven effective with good clinical, functional and radiological results in well selected cases. However not insignificant rates of sagittal collapse and recurrence of kyphosis with or without clinical implications have also been reported. Most of the failures were attributed to lack of anterior column integrity and relatively inferior robustness of earlier posterior short segment constructs. With better understanding of fracture biomechanics, better implant designs and evolution of strategies to increase the biomechanical strengths of posterior constructs, the rates of kyphosis recurrence and implant failure have been significantly reduced. Although there is lack of robust evidence to guide a surgeon to the best approach for a particular fracture, adhering to basic biomechanical principals increases the efficacy and reliability of short segment fixation. This narrative review highlights the status of short segment fixation in dorsolumbar spine injuries with emphasis on patient selection and strategies to increase effectiveness and reduce failures of short segment fixation.

Clinical Features and Treatment Outcomes of Acute Multiple Thoracic and Lumbar Spinal Fractures : A Comparison of Continuous and Noncontinuous Fractures

Objective

The treatment of multiple thoracolumbar spine fractures according to fracture continuity has rarely been reported. Herein we evaluate the clinical features and outcomes of multiple thoracolumbar fractures depending on continuous or noncontinuous status.

Methods

From January 2010 to January 2016, 48 patients with acute thoracic and lumbar multiple fractures who underwent posterior fusion surgery were evaluated. Patients were divided into two groups (group A : continuous; group B : noncontinuous). We investigated the causes of the injuries, the locations of the injuries, the range of fusion levels, and the functional outcomes based on the patients’ general characteristics.

Results

A total of 48 patients were enrolled (group A : 25 patients; group B : 23 patients). Both groups had similar pre-surgical clinical and radiologic features. The fusion level included three segments (group A : 4; group B : 5) or four segments (group A : 19; group B : 5). Group B required more instrumented segments than did group A. Group A scored 23.5 and group B scored 33.4 on the Korean Oswestry Disability Index (KODI) at the time of last follow-up. In both groups, longer fusion was associated with worse KODI score.

Conclusion

In this study, due to the assumption of similar initial clinical and radiologic features in both group, the mechanism of multiple fractures is presumed to be the same between continuous and noncontinuous fractures. The noncontinuous fracture group had worse KODI scores in long-term follow-up, thought to be due to long fusion level. Therefore, we recommend minimizing the number of segments that are fused in multiple thoracolumbar and lumbar fractures when decompression is not necessary.

Comparing the Biomechanical Stability of Cortical Screw Trajectory Versus Standard Pedicle Screw Trajectory for Short- and Long-Segment Posterior Fixation in 3-Column Thoracic Spinal Injury

Background

Information on the performance of posterior fixation with cortical screw (CS) versus pedicle screw (PS) trajectories for stabilizing thoracolumbar burst fractures is limited. Therefore, we sought to analyze stability with CS versus PS in short- and long-segment fixations using a 3-column spinal injury model.

Methods

Nondestructive flexibility tests: (1) intact, (2) intact + short fixation, (3) intact + long fixation, (4) after burst fracture, (5) short fixation + burst fracture, and (6) long fixation + burst fracture using thoracic spine segments (7 CS, 7 PS).

Results

With CS, the range of motion (ROM) was significantly greater with short-segment than with long-segment fixation in all directions, with and without burst fracture (P ≤ .008). With PS and burst fracture, ROM was significantly greater with short fixation during lateral bending and axial rotation (P < .006), but not during flexion-extension (P = .10). Groups with CS versus PS were not significantly different after burst fracture during flexion-extension and axial rotation, with short (P ≥ .58) or long fixation (P ≥ .17). During lateral bending, ROM was significantly greater with CS versus PS, without burst fracture (long fixation, P = .02) and with burst fracture (short and long fixation, P ≤ .001).

Conclusions

CS trajectory is a valid alternative to PS trajectory for thoracic spine fixation in 3-column spinal injuries, and long-segment fixation is superior to short-segment fixation with either.

Percutaneous fixation of thoracolumbar vertebral fractures

Surgical treatment of patients with thoracolumbar vertebral fracture without neurological deficit is still controversial.

Management of vertebral fracture with percutaneous fixation was first reported in 2004.

Advantages of percutaneous fixation are: less tissue dissection; decreased post-operative pain; decreased bleeding and operative time (depending on the steep learning curve); better screw positioning with fluoroscopy compared with an open freehand technique; and a decreased infection rate.

The limitations of percutaneous fixation of vertebral fractures include increased radiation exposure to the patient and the surgeon, together with the steep learning curve for this technique.

Adding a screw at the level of the fractured vertebra has the advantages of incorporating fewer motion segments with less operative time and bleeding. This also increases the axial, sagittal and torsional stiffness of the construct.

Percutaneous fixation alone without grafting is sufficient for treating type A and B1 (AO classification) thoracolumbar fractures with satisfactory results concerning kyphosis reduction when compared with open instrumentation and fusion and with open fixation.

Type C and B2 fractures (ligamentous injuries) should undergo fusion since the ligamentous healing is mechanically weak, increasing the risk of instability.

This review offers a detailed description of percutaneous screw insertion and discusses the advantages and disadvantages.

Cite this article: EFORT Open Rev 2018;3:604-613. DOI: 10.1302/2058-5241.3.170026.

Is Short Same-Segment Fixation Really Better than Short-Segment Posterior Fixation in the Treatment of Thoracolumbar Fractures?

STUDY DESIGN

A retrospective study.

OBJECTIVE

This retrospective study assessed whether short same-segment fixation (SSSF) is better than short-segment posterior fixation (SSPF) for reducing thoracolumbar fractures, improving the kyphosis angle, maintaining vertebral height, or reducing the incidence of broken screws.

SUMMARY OF BACKGROUND DATA

In clinical practice, single-segment thoracolumbar fractures were then more likely to be treated with SSPF that included pedicle fixation at the level of the fracture (short same-segment fixation, or SSSF). Whether SSSF could really achieve vertebral height recovery, improve the kyphosis, reduce postoperative kyphosis loss, and reduce the incidence of internal fixation failure better than SSPF.

METHODS

Patients treated with SSPF or SSSF at our institution during 2006 to 2014 were reviewed. Effects of thoracolumbar fracture reduction, improved kyphosis angle, and maintaining vertebral height were compared between groups. Logistic regression analysis was used to identify factors related to instrumentation breakage and correlation analysis to assess possible relations between loss of correction of the kyphosis angle (LAWAC) and other factors.

RESULTS

Altogether, 130 patients were enrolled (53 SSPF, 77 SSSF). SSPF (22F, 31M) group's mean (range) age was 37.7 (16-60) years, and the follow-up was 26.2 (9-120) months. SSSF (27F, 50M) group's mean (range) age was 39.3 (17-61) years, and the follow-up was 23.2 (9-60) months. All patients underwent either internal fixation or screw repair. Immediately postoperatively, restoration after middle vertebral fractures was better in SSSF patients than in SSPF patients (P = 0.003), with no differences in other fracture-related factors (P > 0.05). Only LAWAC was significantly associated with instrumentation breakage (P < 0.05). Also, immediately postoperatively, the anterior/posterior vertebral heights ratio was negatively related to LAWAC.

CONCLUSION

Pedicle fixation of the fracture did not obtain better recovery of anterior or posterior vertebral heights nor did it improve AWA restoration. There was no significant difference in LAWAC between groups or in the incidence of broken screws. LAWAC may increase the incidence of broken screws.

LEVEL OF EVIDENCE

4.

Biomechanical effects of USS fixation with different screw insertion depths on the vertebrae stiffness and screw stress for the treatment of the L1 fracture

OBJECTIVE

To evaluate the biomechanical effects of internal fixation with different screw insertion depths on vertebrae stiffness and screw stress for L1 fracture.

METHODS

The established L1 fracture was fixed with 10 different depths of screw insertion: 10-100% screw-path length (SPL). Loading on the T12 endplate was simulated.

RESULTS

Screws inserted to 60-100% depths has a higher axial displacement of screw against injured vertebrae and maximum stress of screws compared to those of screws inserted to 30-50% depths and 10-20% (P< 0.05). No significant difference was noted among 60-100% SPL groups. Under single loading condition, the incidence rate of maximum stress of each screw ranged from 16.7-50.0%. Chi-square test showed superior screw has a higher incidence rate of maximum stress than inferior screw (P< 0.05).

CONCLUSIONS

Screws inserted to 60% depth or more can achieve effective strength to withstand the postoperative height correction loss of the L1 vertebrae fracture. However, continuous prolonged depth of screw insertion did not significantly increase the effective strength of the screw against injured vertebrae and maximum equivalent stress of screws. The incidence rate of the maximum stress of each screw in correlated with position of screw insertion but not associated with the screw insertion depth.

[To fix the unstable region of sagittal injured unit symmetrically with pedicle screws combined with bone graft fusion for treating thoracolumbar fractures]

Objective

To discuss the security and effectiveness of fixing the unstable region of sagittal injured unit symmetrically with pedicle screws combined with bone graft fusion for treating thoracolumbar fractures.

Methods

A series of 65 patients with a single level thoracolumbar fracture between November 2011 and November 2015 were included in the study. There were 41 males and 24 females with an average age of 36.7 years (range, 23-60 years). The fracture segments included T ₇ 1 case, T ₉ in 2 cases, T ₁₀ in 4 cases, T ₁₁ in 8 cases, T ₁₂ in 14 cases, L ₁ in 19 cases, L ₂ in 13 cases, L ₃ in 3 cases, and L ₄ in 1 case. According to AO classification, there were 34 cases classified as type A, 27 cases type B, and 4 cases type C. The neurological function was evaluated by American Spinal Injury Association (ASIA) grade score, there were 1 case at grade A, 2 cases grade B, 6 cases grade C, 15 cases grade D, and 41 cases grade E. The thoracolumbar injury severity score (TLICS) was 4 in 9 cases, 5 in 29 cases, 6-8 in 23 cases, 9-10 in 4 cases. The time form injury to operation was 2-12 days (mean, 5.3 days). The fractured vertebra, along with the superior and inferior discs were defined as a injured unit and divided into three parts on the sagittal position: region Ⅰ mainly including the superior disc, cephalic 1/3 of injured vertebra, and posterior ligamentous complex as to oppose; region Ⅱ mainly including the middle 1/3 of injured vertebra, pedicles, lamina, spinous process, and supraspinal ligament; region Ⅲ mainly including the inferior disc, caudal 1/3 of injured vertebra, and posterior ligamentous complex as to oppose. The unstable region was defined as the key injured region of the vertebra. Pedicle screws were fixed symmetrically and correspondingly with bone grafting to treat thoracolumbar fractures. The neurological status, ratio of anterior body height, and sagittal Cobb angle were collected at preoperation, immediate after operation, and last follow-up to evaluate surgical and clinical outcomes.

Results

All patients accepted operation safely and were followed up 12-24 months (mean, 17.3 months). Cerebrospinal fluid leakage occurred in 3 patients, and cured by symptomatic treatment. There was no complications such as loosening, displacement, and breakage of internal fixator. Bony fusion was achieved in all patients at 10-13 months (mean, 11.4 months) after operation. At last follow-up, according to ASIA grading, 1 case was grade A, 1 grade B, 3 grade C, 9 grade D, and 51 grade E, showing significant difference when compared with preoperative data ( Z=-2.963, P=0.014). The ratio of anterior body height at preoperation, immediate after operation, and last follow-up were 53.2%±6.8%, 91.3%±8.3%, 89.5%±6.6% respectively; and the sagittal Cobb angle were (16.3±8.1), (2.6±7.5), (3.2±6.8)° respectively. The ratio of anterior body height and the sagittal Cobb angle at immediate after operation and at last follow-up were significantly improved when compared with preoperative values ( P<0.05), but no significant difference was found between at immediate after operation and at last follow-up ( P>0.05).

Conclusion

It is safe and reliable to treat thoracolumbar fractures under the principle of fixing the unstable region of injured unit symmetrically with pedicle screws combined with bone grafting.

Clinical Effects of Posterior Limited Long-Segment Pedicle Instrumentation for the Treatment of Thoracolumbar Fractures

Objective: The purpose of this study was to assess the clinical effects of treating thoracolumbar fractures with posterior limited long-segment pedicle instrumentation (LLSPI). Methods: A total of 58 thoracolumbar fracture patients were retrospectively analyzed, including 31 cases that were fixed by skipping the fractured vertebra with 6 screws using LLSPI and 27 cases that were fixed by skipping the fractured vertebra with 4 screws using short-segment pedicle instrumentation (SSPI). Surgery time, blood loss, hospital stay, Oswestry disability index (ODI), neurological function, sagittal kyphotic Cobb angle (SKA), percentage of anterior vertebral height (PAVH), instrumentation failure, and the loss of SKA and PAVH were recorded before and after surgery. Results: No significant differences were observed in either the surgery time or hospital stay (P < 0.05), while there were significant differences in blood loss between the two groups. At the final follow-up, both the ODI and the neurological status were notably improved compared to those at the preoperative state (P < 0.05), but the difference between the two groups was relatively small. Furthermore, the SKA and PAVH were notably improved at the final follow-up compared to postoperative values (P < 0.05), but no significant difference was observed between the two groups. During long-term follow-up, the loss of SKA and PAVH in the LLSPI group was significantly less than that in the SSPI group (P < 0.05). Conclusion: Based on strict criteria for data collection and analysis, the clinical effects of LLSPI for the treatment of thoracolumbar fractures were satisfactory, especially for maintaining the height of the fractured vertebra and reducing the loss of SKA and instrumentation failure rates.

Three-step Reduction Therapy of Integrated Chinese and Western Medicine for Thoracolumbar Burst Fracture

Objective: To investigate and compare the efficacy of three-step reduction (TSR) therapy of integrated Chinese and Western Medicine and posterior open (PO) surgery for thoracolumbar burst fracture. Methods: We selected 60 patients diagnosed with thoracolumbar burst fracture and received treatment in our hospital from December 2014 to March 2017. According to randomized digital table, they were randomly divided into TSR and PO groups. VAS pain grade, Oswestry disability index, height of centrum front, Cobb's angle of spine, bleeding, and complication of internal fixation of the two groups were compared. Results: Postoperative reduction of injured centrum, regained volume of canalis vertebralis, volume of bleeding, and early functional rehabilitation of TSR group were better than that of PO groups (P < 0.05). Conclusion: Through three-step reduction combined pedicle screw fixation surgery, we can achieve satisfied reduction of thoracolumbar burst fracture, rebuild the height of centrum, recover the biomechanics function of spine, and reduce bleeding. Three-step reduction therapy is an effective therapy for thoracolumbar burst fracture.

A comparative study of single-stage transpedicular debridement, fusion, and posterior long-segment versus short-segment fixation for the treatment of thoracolumbar spinal tuberculosis in adults: minimum five year follow-up outcomes

DESIGN

This a retrospective study in single centre.

OBJECTIVE

The objective of this retrospective clinical study is to compare the long-term clinical efficacy of posterior long-segment and short-segment fixation with single-stage transpedicular debridement and fusion for the treatment of thoracolumbar spinal tuberculosis in adults.

METHODS

Sixty-six cases of thoracolumbar tuberculosis were treated by single-stage transpedicular debridement, bone graft fusion, and pedicle screw fixation. Thirty-five cases were under long-segment fixation (group A) and 31 cases were under short-segment fixation (group B). These patients were followed up for a minimum of five years. The clinical and radiographic results for these patients were analyzed and compared.

RESULTS

All 66 patients were completely cured during the follow-up. All patients had significant improvement of neurological condition and visual analogue scale pain scores at the final follow-up. The average operation duration and blood loss in group A were more than that in group B. Kyphosis Cobb angle of both groups was significantly corrected after surgical management. The correction rate of Cobb angle in group A was significantly higher than that in group B at the time of immediate post-operative period or the last follow-up (P < 0.05). The correction loss of group A was significantly less than that in group B (P < 0.05).

CONCLUSION

Both posterior long-segment and short-segment pedicle screw fixations for the treatment of thoracolumbar spinal tuberculosis have significant effects in the correction of kyphosis and the improvement of neurological function. Although the blood loss and operation time of long-segment fixation were more than that of short-segment fixation, long-segment fixation was superior to the short-segment fixation in the correction of kyphosis and the maintenance of spinal stability, especially in the prevention of long-term correction loss.

[Posterior short-segment fixation including the fractured vertebra for severe unstable thoracolumbar fractures]

Objective

To discuss the effectiveness of posterior short-segment fixation including the fractured vertebra for severe unstable thoracolumbar fractures using pedicle screw fixation.

Methods

Between May 2008 and July 2013, 52 patients of severe unstable thoracolumbar fractures were treated through posterior short-segment fixation including the fractured vertebra using pedicle screw fixation. There were 33 males and 19 females with an age of 21-56 years (mean, 37.9 years). The causes of thoracolumbar burst fractures included fall from height in 32 cases, traffic accidents in 16 cases, and others in 4 cases. The load sharing classification (LSC) score was 7-9 (mean, 7.85). The levels involved included T ₁₁ in 4 cases, T ₁₂ in 19 cases, L ₁ in 25 cases, and L ₂ in 4 cases. According to Frankel classification, there were 2 cases of grade A, 4 cases of grade B, 8 cases of grade C, 11 cases of grade D, and 27 cases of grade E. The rate of spinal canal occupying was 24.2%-76.7% (mean, 47.1%). The time from injury to operation was 3-5 days (mean, 3.6 days). The effectiveness was assessed by the changes of injured vertebral Cobb angle, anterior vertebral height, and the Frankel grading at pre- and post-operation.

Results

The operation time was 85-127 minutes (mean, 106.5 minutes). The intraoperative blood loss was 90-155 mL (mean, 137.6 mL). All the incision healed at first intension. Forty-seven patients were followed up 19-27 months (mean, 23.2 months), and no incision infection, screw loosening, or other internal fixation failures was found during follow-up. The injured vertebral Cobb angle and anterior vertebral height at immediate after operation or at last follow-up were significantly improved when compared with preoperative values ( P<0.001). There was a loss of injured vertebral Cobb angle and anterior vertebral height at last follow-up, but no significant difference was found between at immediate after operation and at last follow-up ( P>0.05). The Frankel grade improved by 0-2 grades at last follow-up, showing significant difference when compared with preoperative grades ( Z=15.980, P=0.003).

Conclusion

Posterior short-segment fixation including the fractured vertebra for severe unstable thoracolumbar fractures (LSC≥7) using pedicle screw fixation can correct the kyphosis deformity, restore vertebral body height, and aviod the need of anterior reconstruction.

Spontaneous Reduction of Fractured Thoracolumbar Spine With Complete Dislocation: Case Report With Literature Review

Fractures and dislocations with complete lateral displacement of the spine at the lumbar and thoracic levels are some of the most severe types of thoracolumbar trauma. They are usually caused by high-energy trauma and accompanied by extreme, life-threatening injuries and neurological deficits that vary in severity, which may delay operative intervention. It is often difficult to reduce such a complex fracture-dislocation because of the force that the muscles exert on the bone and the injured part of the spinal cord. No absolute guidelines for reduction, fixation, decompression, and fusion of this type of injury have been established. We report a rare case of spontaneous reduction of the fractured thoracolumbar spine with complete dislocation and discuss the management of such severe injuries through review of the existing literature.

Factors predicting long-term outcome after short-segment posterior fixation for traumatic thoracolumbar fractures

Background:

The “gold standard” for instrumentation of unstable thoracolumbar fracture-dislocations is pedicle screw and rod fixation. Although traditional treatment supports long-segment posterior fixation (LSPF), more recent studies show short-segment posterior fixation (SSPF) may be effective, but incur higher failure rates. Here, we evaluated the effectiveness of SSPF in the management of unstable thoracolumbar injuries and analyzed the factors impacting long-term outcomes.

Methods:

In this retrospective analysis of 91 patients with thoracolumbar fractures managed with SSPF alone, we assessed the clinical and radiological parameters at preoperative, postoperative, and follow-up intervals along with reasons for failures of SSPF.

Results:

We analyzed 91 patients (mean age: 33.5 years; Male: Female = 50:41) with thoracolumbar fractures treated with SSPF over a median follow-up period of 30 months. SSPF failures were observed in 26 of 91 (28.6%) patients; the median time to implant failure was 17 months. On univariate analysis, statistically significant factors contributing to failure of SSPF included the presence of a burst fracture, a preoperative LSC (load-sharing classification) score >6, and translation/dislocation. With multinomial regression analysis, the only factor predictive for SSPF failure was the patients' postoperative ambulatory status.

Conclusion:

Patients with thoracolumbar facture dislocations, subjected to axial spinal loading postoperatively, should not be considered for SSPF alone. The following factors also contributed to SSPF failures: a burst fracture, a preoperative LSC score of >6, and/or presence of transverse dislocation.

Is fusion superior to non-fusion for the treatment of thoracolumbar burst fracture? A systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to compare the efficacy and safety between patients with thoracolumbar burst fracture who underwent posterior fixation alone (non-fusion) and supplemented with fusion.

METHODS

A comprehensive search of related literature was performed in PubMed, Embase and the Cochrane library. Clinical outcomes (LBOS and VAS), surgical outcomes (operation time, blood loss, hospital stay and perioperative complications), and radiographic outcomes (kyphotic angle, decreased vertebral body height and segmental motion) were assessed in the meta-analysis. Data analysis was conducted with RevMan 5.3 software.

RESULTS

Five RCTs and three retrospective studies including a total of 445 cases were identified. We found that there was no significant difference in terms of LBOS, VAS, implant-related complications, kyphotic and VBH parameters. However, there was a significant difference regarding blood loss, operation time, segmental motion and donor site pain between fusion and non-fusion.

CONCLUSION

This meta-analysis demonstrated that posterior fixation alone could achieve satisfactory clinical and radiological results in treating thoracolumbar burst fracture. Moreover, posterior fixation without fusion was superior to additional fusion with less blood loss, shorter operation time, better segmental motion and lower donor site pain.

Effectiveness of pedicle screw inclusion at the fracture level in short-segment fixation constructs for the treatment of thoracolumbar burst fractures: a computational biomechanics analysis

When treating thoracolumbar burst fractures (BF), short-segment posterior fixation (SSPF) represents a less invasive alternative to the traditional long-segment posterior fixation (LSPF) approach. However, hardware failure and loss of sagittal alignment have been reported in patients treated with SSPF. Including pedicle screws at the fracture level in SSPF constructs has been proposed to improve stiffness and reliability of the construct. Accordingly, the biomechanical performance of the proposed construct was compared to LSPF via a computational analysis. Pedicle screws at fracture level improved the performance of the short-segment construct. However, LSPF still represent a biomechanically superior option for treating thoracolumbar BF.

Cost-Utility Analysis of Pedicle Screw Removal After Successful Posterior Instrumented Fusion in Thoracolumbar Burst Fractures

STUDY DESIGN

A cost-utility analysis (CUA).

OBJECTIVE

The aim of this study was to determine the cost-effectiveness of pedicle screw removal after posterior fusion in thoracolumbar burst fractures.

SUMMARY OF BACKGROUND DATA

Pedicle screw instrumentation is a standard fixation method for unstable thoracolumbar burst fracture. However, removal of the pedicle screw after successful fusion remains controversial because the clinical benefits remain unclear. CUA can help clinicians make appropriate decisions about optimal health care for pedicle screw removal after successful fusion in thoracolumbar burst fractures.

METHODS

We conducted a single-center, retrospective, longitudinal matched-cohort study of prospectively collected outcomes. In total, 88 consecutive patients who had undergone pedicle screw instrumentation for thoracolumbar burst fracture with successful fusion confirmed by computed tomography (CT) were used in this study. In total, 45 patients wanted to undergo implant removal surgery (R group), and 43 decided not to remove the implant (NR group). A CUA was conducted from the health care perspective. The direct costs of health care were obtained from the medical bill of each patient. Changes in health-related quality of life (HRQoL) scores, validated by Short Form 6D, were used to calculate quality-adjusted life-years (QALYs). Total costs and gained QALY were calculated at 1 year (1 year) and 2 years (2 years) compared with baseline. Results are expressed as an incremental cost-effectiveness ratio (ICER). Different discount rates (0%, 3%, and 5%) were applied to both cost and QALY for sensitivity analysis.

RESULTS

Baseline patient variables were similar between the two groups (all P > 0.05). The additional benefits of implant removal (0.201 QALY at 2 years) were achieved with additional costs ($2541 at 2 years), equating to an ICER of $12,641/QALY. On the basis of the different discount rates, the robustness of our study's results was also determined.

CONCLUSION

Implant removal after successful fusion in a thoracolumbar burst fracture is cost-effective until postoperative year 2.

LEVEL OF EVIDENCE

3.

Comparing the efficacy of short-segment pedicle screw instrumentation with and without intermediate screws for treating unstable thoracolumbar fractures

It is generally acknowledged that short-segment pedicle screw instrumentation is the preferred surgical method for thoracolumbar fractures. However, the use of short-segment instrumentation with or without intermediate screws at the fracture level remains controversial.We retrospectively evaluated 44 patients (28 men, 16 women) with unstable thoracolumbar fractures. The patients were divided into 2 groups according to the surgical method used. In group 1, 24 patients underwent surgery with a posterior approach via short-segment pedicle screw instrumentation (1 level above and 1 level below the fractured level). In group 2, 20 patients received an additional 2 screws at the fractured vertebrae. Clinical and radiologic parameters were evaluated before surgery and at 1 week, 6 months, and 1 year after surgery.We found no significant difference in the demographic characteristics between the 2 groups. No significant difference was observed in the operative time and intraoperative blood loss between the 2 groups. Clinical outcomes also showed no significant differences between the groups preoperatively or at all follow-up periods. The correction of the Cobb angle (CA) 1 week after surgery was better in group 2, whereas the anterior vertebral body height of the fractured level (AVHF) and compression ratio of the AVHF (AVHFCR) were not significantly different between the 2 groups 1 week after surgery. Moreover, group 2 had better maintenance of restored CA, AVHF, and AVHFCR at the fractured level than did group 1 at 6 months and 1 year postoperatively. In addition, the reduction of mid-sagittal diameter (MSD) of spinal canal 1 week and 1 year after surgery was better in group 2. Besides, bone fragments in the spinal canal have a tendency to be less in group 2 1 week and 1 year after surgery.Reinforcement with intermediate screws for a single thoracolumbar fracture not only enhanced the stability of the internal fixation system, but it was also conducive to the correction of kyphosis and the maintenance of the reduction effects. Furthermore, this method is helpful to restore the spinal canal and reduce the bone fragments in the spinal canal. However, more long-term follow-up studies are needed.

Treatment of Lumbar Split Fracture-Dislocation With Short-Segment or Long-Segment Posterior Fixation and Anterior Fusion

STUDY DESIGN

Retrospective analysis of 16 patients.

SUMMARY OF BACKGROUND DATA

The lumbar split fracture-dislocation is a rare but severe injury, which is type C1.2.1 fracture in the Association for the Study of Internal Fixation spine fracture classification. The axial compressive and torsional force shattered the vertebral body into 2 halves and displaced them rotationally. This kind of fracture is so highly unstable that the treatment is very challenging.

PURPOSE

The purpose of this study was to report and compare on clinical outcome and complications of patients with lumbar split fracture-dislocation which had been treated either short-segment or long-segment posterior fixation and anterior fusion.

MATERIALS AND METHODS

A total of 16 patients with acute, split fracture-dislocation of the lumbar spine from March 2000 to May 2009 in our department were recruited. Seven patients (group I) treated by long-segment posterior fixation (2 levels above and 2 below the fracture) and anterior corpectomy and strut grafting. With the improvement of surgical technique and instrument, 9 patients after August 2004 were treated by short-segment posterior fixation (1 level above and 1 below, and included the fractured vertebrae itself) and anterior discectomy and strut grafting. The intraoperative blood loss, operation time, complications of operation, time to achieve bony fusion, Frankel scale, Oswestry Disability index, and Visual Analogue Pain Scale the Cobb angle were collected and compared.

RESULTS

The mean follow-up was 33.4 months for group I and 36.2 months for group II. The operation time was 457.1 minutes in group I which was significantly longer than 240.0 minutes in group II. The total blood loss was for group I was 2001.4 mL (range, 1580-2500 mL) and for group II was 730.6 mL (range, 430-950 mL). There was no neurological deterioration after surgery in both group and no difference in neurological outcome between the 2 groups. The loss of correction in Cobb angle averaged at the final evaluation was 2 and 5 degrees for groups I and II, respectively. There was no radiologically visible pseudarthrosis. The postoperative Visual Analogue Pain Scale score was 3.3 and 2.7 for groups I and II, respectively. In the SF-36 survey, after surgery the domains Role physical and Bodily pain improved significantly only in group B (P<0.05 and P=0.06, respectively). Time to achieve bony fusion in group I was 7.9 months which was significantly longer than 3.8 months in group II. Complications included 3 urinary infections, 1 decubitus ulcer, and 1 superficial infection that were cured by antibiotics. Screw breakage was found in 1 patient in the group II.

CONCLUSIONS

The lumbar sagittal split fracture-dislocation is a rare but severe injury, which can be treated either with short-segment or long-segment posterior fixation and anterior fusion. The short construct with pedicle screws in the fractured vertebrae followed by the maneuver of rod derotation can obtain anatomic reduction, restoration of 3-column alignment, and decompress the affected neural elements by restoration of the normal canal dimension. It may be a better therapeutic option for the highly unstable lumbar fracture of C1.2.1.

Biomechanical comparison of short-segment posterior fixation including the fractured level and circumferential fixation for unstable burst fractures of the lumbar spine in a calf spine model

OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.

Minimally Invasive Posterior Decompression Combined With Percutaneous Pedicle Screw Fixation for the Treatment of Thoracolumbar Fractures With Neurological Deficits: A Prospective Randomized Study Versus Traditional Open Posterior Surgery

STUDY DESIGN

Prospective randomized cohort study.

OBJECTIVE

To compare the surgical results of minimally invasive posterior decompression combined with percutaneous pedicle screws fixation (minimally invasive surgery [MIS]) and posterior open surgery (OS) for the treatment of thoracolumbar fracture with neurological deficits.

SUMMARY OF BACKGROUND DATA

Thoracolumbar fracture with neurological deficits usually undergoes surgical intervention. OS can achieve satisfied results, but the main disadvantage is approach-related complications. No study, however, focused on the treatment of this disease by MIS through posterior approach.

METHODS

Sixty consecutive cases of thoracolumbar fractures with neurological deficits were randomized into MIS group and OS group. Incision length, blood loss, postoperative drainage volume, hospitalization days, blood transfusion rate, analgesic use rate, and x-ray exposure time were used to evaluate the perioperative information and Visual Analog Scale (VAS), Japanese Orthopedics Association (JOA) score, and American Spinal Injury Association grade for patients' symptom. For radiological assessment, sagittal Cobb angle, percentage of vertebral height, and vertebral wedging angle were measured.

RESULTS

Fifty-nine of sixty patients were followed-up for at least 12 months. MIS group was superior in perioperative information (P < 0.05), except in the operative time (P = 0.165) and x-ray time (P = 0.000). The operative time seemed longer in MIS group, but no significant difference was found. The x-ray time was significantly higher in MIS group. The mean Visual Analog Scale and Japanese Orthopedics Association scores of the final follow-up in MIS group were better than that in OS group (P < 0.05). Patients in both group achieved a similar neurological recovery according to American Spinal Injury Association grade (P = 0.760). A broken screw was found in one patient in MIS group and a broken rod in one patient in OS group.

CONCLUSION

MIS group has achieved the similar effect of OS group and it can minimize the approach-related complication. It also faced with some shortages, such as larger radiation dose and longer learning curve.

LEVEL OF EVIDENCE

2.

Can implant removal restore mobility after fracture of the thoracolumbar segment?

Background and purpose - Randomized trials have found that treating spinal burst fractures with reduction and posterior fixation is adequate without the use of bone grafting for definitive fusion. Restitution of intervertebral mobility of such an unfused segment after fracture healing may unload the adjacent parts of the spine and reduce the risk of degeneration of these segments. We used radiostereometry (RSA) to study whether late implant removal would restore the intervertebral mobility of a thoracolumbar segment treated with posterior instrumentation but no bone grafting for unstable spinal fracture. Patients and methods - We identified 7 patients with implant-related back pain at least 1.5 years after a thoracolumbar fracture (Th12 or L1) treated with reduction and posterior instrumentation. The implants were removed and tantalum indicators for RSA were inserted. 3 months later, each patient was examined with RSA. The intervertebral translations and rotations of the thoracolumbar segment, induced by change in position from flexion to extension, were measured. Progressive deformity was registered by conventional radiography and the overall clinical outcome was assessed by the patients. Results - According to RSA, all 7 patients regained some mobility of the fractured thoracolumbar segment. In 1 patient who was primarily treated for a flexion-distraction type of injury, conventional radiography revealed a progressive kyphotic deformity 3 months after implant removal and the clinical outcome was poor. According to the patients, 1 had a fair clinical outcome and 5 had good outcome. Interpretation - Late implant removal may restore segmental mobility after posterior fracture fixation of the thoracolumbar segment if bone grafting has not been used. The clinical consequences, positive or negative, of the residual mobility demonstrated in our small number of patients should be evaluated in studies based on extended patient series and with different fracture types.

Which patients risk segmental kyphosis after short segment thoracolumbar fracture fixation with intermediate screws?

INTRODUCTION

The use of intermediate screws in fractured vertebrae has been proposed to decrease the number of fused levels in thoracolumbar fractures and to enable short fixations. The aim of this study was to evaluate the results of this technique and to establish predictive factors involved in loss of segmental kyphosis correction (LKC).

METHODS

Forty-three patients who underwent short-segment spinal fixation with intermediate screws for a thoracolumbar spine fracture in a two-year time period were enrolled in the study. Patients had AO-type A3, A4 and B2 thoracolumbar fractures. Radiological parameters included segmental kyphosis (SK), vertebral wedge angle (VWA) and loss of anterior and posterior vertebral body height. Patients were evaluated up to one-year follow-up. The correlation between LKC and potential risk factors, such as smoking habit, sex, age, neurological status and BMI was evaluated.

RESULTS

Mean preoperative SK was 16.5°±6.5°, and it decreased to 3.4°±3.5° postoperatively (P<0.01). At the one-year follow-up mean SK dropped to 5.5°±3.9° (P<0.01). Mean preoperative VWA was 20.0°±8.1°, and significantly improved to 6.3°±3.1° after surgery (P<0.01). There was a mean LKC of 1.8°±2.1°at one year. LKC mildly correlated with body mass index (BMI, r: +0.31), and obese patients (BMI>30) had an increased risk of LKC at the one-year follow-up (P=0.03; odds ratio [OR]=3.2).

DISCUSSION

Analysis of the radiological data at one-year follow-up showed that all the evaluated parameters were associated with a mild loss of correction, with no impact on the clinical outcomes or implant failure. These findings confirm the trends reported in the literature. The correlation between LKC and clinical features, such as BMI, age, sex, smoking habit and preoperative neurological status was investigated. Interestingly, a positive correlation was observed between BMI and LKC, and obese patients with BMI>30 had an increased risk of LKC at one-year follow-up (OR 3.2); to our knowledge this finding has never before been reported.

CONCLUSION

Short-segment fixation with intermediate screws is a viable technique with positive clinical and radiological outcomes at one-year follow-up. However, surgeons should be aware that in obese patients (BMI>30) this technique is associated with an increased risk of LKC.

LEVEL OF EVIDENCE

3.

Biomechanical Analysis of Pedicle Screw Fixation for Thoracolumbar Burst Fractures

Treatment of unstable thoracolumbar burst fractures remains controversial. Long-segment pedicle screw constructs may be stiffer and impart greater forces on adjacent segments compared with short-segment constructs, which may affect clinical performance and long-term out come. The purpose of this study was to biomechanically evaluate long-segment posterior pedicle screw fixation (LSPF) vs short-segment posterior pedicle screw fixation (SSPF) for unstable burst fractures. Six unembalmed human thoracolumbar spine specimens (T10-L4) were used. Following intact testing, a simulated L1 burst fracture was created and sequentially stabilized using 5.5-mm titanium polyaxial pedicle screws and rods for 4 different constructs: SSPF (1 level above and below), SSPF+L1 (pedicle screw at fractured level), LSPF (2 levels above and below), and LSPF+L1 (pedicle screw at fractured level). Each fixation construct was tested in flexion-extension, lateral bending, and axial rotation; range of motion was also recorded. Two-way repeated-measures analysis of variance was performed to identify differences between treatment groups and functional noninstrumented spine. Short-segment posterior pedicle screw fixation did not achieve stability seen in an intact spine (P<.01), whereas LSPF constructs were significantly stiffer than SSPF constructs and demonstrated more stiffness than an intact spine (P<.01). Pedicle screws at the fracture level did not improve either SSPF or LSPF construct stability (P>.1). Long-segment posterior pedicle screw fixation constructs were not associated with increased adjacent segment motion. Al though the sample size of 6 specimens was small, this study may help guide clinical decisions regarding burst fracture stabilization. [Orthopedics. 2016; 39(3):e514-e518.].

Biomechanical evaluation of monosegmental pedicle instrumentation in a calf spine model and the role of fractured vertebrae in screw stability

Background

Monsegmental pedicle instrumentation (MSPI) has been used to treat thoracolumbar fractures. However, there are few reports about the biomechanical characteristics of MSPI compared with traditional short-segment pedicle instrumentation (SSPI) in management of unstable thoracolumbar fractures, and the influence of vertebral fracture on screw stability is still unclear.

Methods

This study was to compare the immediate stability between MSPI and SSPI in management of unstable L1 fracture, and to evaluate the role of fractured vertebrae in screw stability. Two studies were performed: in the first study, sixteen fresh calf spines (T11-L3) were divided into two groups, in which unstable fractures at L1 were produced and then instrumented with MSPI or SSPI respectively. The range of motion (ROM) and lax zone (LZ) of specimens were evaluated with pure moment of 6 Nm loaded. The second study measured and compared the pullout strength of screws inserted in to 16 intact and fractured vertebrae of calf spines (L1-3) respectively. The correlation of pullout strength with load sharing classification (LSC) of fractured vertebrae was analyzed.

Results

No significant difference in the ROM and LZ of the destabilized segments after fixation between MSPI and SSPI, except in axial rotation of ROM (P < 0.05). After fatigue cyclic loading, the MSPI showed a significant increase of ROM during lateral bending and axial rotation (P < 0.05); however, there were no significant differences in the LZ during all loading models between groups (P > 0.05). The mean pullout strength of pedicle screws in fractured vertebrae decreased by 13.7 %, compared with that of intact vertebrae (P > 0.05), and had a low correlation with LSC of the fractured vertebrae (r = 0.293, P > 0.05).

Conclusions

MSPI can provide effective immediate stability for management of unstable thoracolumbar fractures; however, it has less fatigue resistance during lateral bending and axial rotation compared with SSPI. LSC score of fractured vertebrae is not a major influence on the pullout strength of screws.

Effect of the percutaneous pedicle screw fixation at the fractured vertebra on the treatment of thoracolumbar fractures

PURPOSE

The purpose of this study was to evaluate the efficacy and safety of percutaneous pedicle screw fixation at the fractured vertebra in the treatment of thoracolumbar fractures.

METHODS

Thirty-two consecutive patients were enrolled in the study. All patients received percutaneous pedicle screw fixation, and they were randomly divided into two groups to undergo either the placement of pedicle screws into the fractured vertebra (fractured group) or not (control group). The operation time and intra-operative blood loss were recorded. Oswestry disability index (ODI) questionnaire and visual analogue scale (VAS) as clinical assessments were quantified. Radiographic follow-up was defined by the vertebral body index (VBI), anterior vertebral body height (AVBH), and Cobb angle (CA).

RESULTS

No significant difference was observed in the operation time and intra-operative blood loss between the two groups. Clinical results (VAS and ODI scores) showed no significant difference during all the follow-up periods. In the fractured group, there were better correction and less loss of AVBH and VBI compared with the control group. However, post-operative correction of the CA immediately after surgery and the correction loss at the final follow-up showed no significant difference between the two groups.

CONCLUSION

Percutaneous screw fixation combined with intermediate screws at the fractured vertebra could more effectively restore and maintain fractured vertebral height, and is an acceptable, minimally invasive surgical choice for patients with type A thoracolumbar fractures.