Which anatomic structures are responsible for the reduction loss after hybrid stabilization of osteoporotic fractures of the thoracolumbar spine?

Satisfactory 2-year outcome of minimal invasive hybrid stabilization with double treated screws for unstable osteoporotic spinal fractures

PURPOSE

This study evaluates whether the fracture level alters the outcomes of minimally invasive hybrid stabilization (MIHS) with double-threaded, uncemented polyaxial screws for unstable osteoporotic vertebral fractures.

METHODS

This prospective cohort study included 73 patients (71.23% females, mean age: 79.9 ± 8.8 years) with unstable OF 3-4 fractures treated by MIHS between Nov 2015-Jan 2018. Patient characteristics, operative data, clinical outcomes, complications, radiological outcomes, and midterm (24-month) follow-up regarding functionality, pain, and quality of life were analyzed.

RESULTS

Patients had thoracolumbar (71.23%), thoracic (10.97%), and lumbar (17.8%) fractures. Operative time was < 120 min in 73.97% of patients, with blood loss < 500 ml in 97.25% of cases. No in-hospital mortality was recorded. Spine-associated complications occurred in 15.07% of patients, while 36.98% of patients had urinary tract infections (n = 12), pneumonia (n = 5), and electrolyte disturbances (n = 9). The mean length of hospital stay was 13.38 ± 7.20 days. Clinically-relevant screw loosening occurred in 1.7% of screws, and secondary adjacent fractures were diagnosed in 5.48% of patients. The alpha-angle improved significantly postoperatively (mean change: 5.4°) and remained stable for 24 months. The beta-angle improved significantly from 16.3° ± 7.5 to 10.8° ± 5.6 postoperatively but increased slightly to 14.1° ± 6.2 at midterm follow-up. Although no differences were seen regarding baseline data, clinical outcomes, and complications, fracture level significantly altered the COMI score at 24 months with no effect on pain score or quality-of-life.

CONCLUSION

MIHS using polyaxial screws is a safe treatment for single-level osteoporotic spinal fractures. Fracture level did not alter radiological reduction loss; however, it significantly altered patients' function at 24 months.

Effectiveness of the Endplate Reduction Technique Combined With Bone Grafting for the Treatment of Thoracolumbar Fractures by Using Posterior Short-Segment Fixation

Objective: This study aimed to examine the effect of the endplate reduction (EPR) technique combined with bone grafting for treating thoracolumbar burst fractures using posterior short-segmental fixation.Methods: Patients with thoracolumbar fractures admitted between January 2018 and October 2021 were retrospectively analyzed, and those meeting the criteria were assigned to the EPR group and the intermediate screws (IS) group. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), upper endplate line (UEPL), upper intervertebral angle (UIVA), and upper intervertebral disc height (UIDH) indices were examined and compared preoperatively, first day postoperatively, as well as at 12 months postoperatively.Results: The result indicated that the EPR group achieved better MVBH reduction (p < 0.001), UEPL reduction (p < 0.001), vertebral body fracture healing (p = 0.006), as well as implant breakage (p = 0.04) than the IS group; VWA (p < 0.001), CA (p = 0.005), AVBH (p < 0.001), MVBH (p < 0.001), UEPL (p < 0.001), and UIDH (p < 0.001) were lost after reduction less than those in the IS group. There was no significant difference in operative time (p = 0.315) and intraoperative bleeding (p = 0.274) between the 2 groups.Conclusion: The EPR group achieved better results in repositioning and maintaining MVBH and endplate morphology, with less correction loss after the reduction of the VWA, CA, AVBH, and endplate morphology. The EPR group exhibited a better healing pattern after vertebral fracture and disc degeneration was better relieved.

A Finite Element Study on the Treatment of Thoracolumbar Fracture with a New Spinal Fixation System

Objective

In this study, the mechanical properties of the new spinal fixation system (NSFS) in the treatment of thoracolumbar fractures were evaluated by the finite element analysis method, so as to provide a mechanical theoretical basis for the later biomechanical experiments and clinical experiments.

Methods

T12-L2 bone model was constructed to simulate L1 vertebral fracture, and three models of internal fixation systems were established on the basis of universal spinal system (USS): Model A: posterior short-segment fixation including the fractured vertebra (PSFFV); Model B: short-segment pedicle screw fixation (SSPF); Model C: new spinal fixation system (NSFS). After assembling the internal fixation system and fracture model, the finite element analysis was carried out in the ANSYS Workbench 18.0 software, and the stress of nail rod system, fracture vertebral body stress, vertebral body mobility, and vertebral body displacement were recorded in the three models.

Results

The peak values of internal fixation stress, vertebral body stress, vertebral body maximum displacement, and vertebral body maximum activity in Model C were slightly smaller than those in Model B.

Conclusions

Compared with the traditional internal fixation system, the new spinal internal fixation system may have the mechanical advantage and can provide sufficient mechanical stability for thoracolumbar fractures.

Midterm outcome after posterior stabilization of unstable Midthoracic spine fractures in the elderly

Background

The evidence for the treatment of midthoracic fractures in elderly patients is weak. The aim of this study was to evaluate midterm results after posterior stabilization of unstable midthoracic fractures in the elderly.

Methods

Retrospectively, all patients aged ≥65 suffering from an acute unstable midthoracic fracture treated with posterior stabilization were included. Trauma mechanism, ASA score, concomitant injuries, ODI score and radiographic loss of reduction were evaluated. Posterior stabilization strategy was divided into short-segmental stabilization and long-segmental stabilization.

Results

Fifty-nine patients (76.9 ± 6.3 years; 51% female) were included. The fracture was caused by a low-energy trauma mechanism in 22 patients (35.6%). Twenty-one patients died during the follow-up period (35.6%). Remaining patients (n = 38) were followed up after a mean of 60 months. Patients who died were significantly older (p = 0.01) and had significantly higher ASA scores (p = 0.02). Adjacent thoracic cage fractures had no effect on mortality or outcome scores. A total of 12 sequential vertebral fractures occurred (35.3%). The mean ODI at the latest follow up was 31.3 ± 24.7, the mean regional sagittal loss of reduction was 5.1° (± 4.0). Patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral fractures during follow-up (p = 0.03).

Conclusion

Unstable fractures of the midthoracic spine are associated with high rates of thoracic cage injuries. The mortality rate was rather high. The majority of the survivors had minimal to moderate disabilities. Thereby, patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral body fractures during follow-up.

Posterior short segment fixation including the fractured vertebra combined with kyphoplasty for unstable thoracolumbar osteoporotic burst fracture

BACKGROUND

Various studies have described the efficacy and safety of the treatment for unstable thoracolumbar osteoporotic burst fracture, however, there is still no consensus on the optimal treatment regimen. The aim of this study was to evaluate the clinical and radiographic results of posterior short segment fixation including the fractured vertebra (PSFFV) combined with kyphoplasty (KP) for unstable thoracolumbar osteoporotic burst fracture.

METHODS

Forty-three patients with unstable thoracolumbar osteoporotic burst fracture underwent PSFFV combined with KP from January 2015 to December 2017 were analyzed retrospectively. Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) was used to evaluate the clinical outcome, radiological parametres including local kyphotic Cobb angle, percentage of the anterior, middle and posterior height of the fractured vertebra were measured and compared pre-operation, post-operation and at final follow-up.

RESULTS

All patients underwent surgery successfully and with an average follow-up of 19.2 ± 6.7 months (rang 15-32). The VAS decreased from 7.1 ± 2.3 pre-operation to 1.6 ± 0.4 at the final follow-up (p < 0.05). The ODI decreased from 83.1 ± 10.5 pre-operation to 19.2 ± 7.3 (P < 0.05) at the final follow-up. The correction of local kyphotic angle was 16.9° ± 5.3° (p < 0.05), and the loss of correction was 3.3° ± 2.6° (p > 0.05), the correction of anterior vertebral height was 30.8% ± 8.6% (p < 0.05), and the loss of correction was 4.5% ± 3.9% (p > 0.05), the correction of middle vertebral height was 26.4% ± 5.8% (p < 0.05), and the loss of correction was 2.0% ± 1.6% (p > 0.05), the correction of posterior vertebral height was 9.4% ± 6.9% (p < 0.05), and the loss of correction was 1.6% ± 1.3% (p > 0.05). Two cases of screw pullout and 8 cases of cement leakage were observed, but without clinical consequence.

CONCLUSIONS

PSFFV combined with KP is a reliable and safe procedure with satisfactory clinical and radiological results for the treatment of unstable thoracolumbar osteoporotic burst fracture.

[Radiological diagnostics of lumbar spine fractures]

BACKGROUND

The lumbar spine forms the lowermost part of the mobile spinal column. Due to anatomical properties, the lumbar spine is highly flexible in the sagittal directions, thus, rendering it susceptible to both flexion and extension forces with the thoracolumbar junction being the most vulnerable part of it. To date, the modern thoracolumbar spine fracture classification is given by the AOSpine classification system based on the well-known Magerl classification of vertebral fracture morphology but now includes both neurological criteria and clinical modifiers, such as ankylosing spondylitis.

DIAGNOSTICS

Whereas plain radiography remains a mainstay in the diagnostic evaluation of low-energy trauma patients, computed tomography (CT) exhibits its unsurpassed power in polytrauma and plays a decisive role in all equivocal cases where the osseous situation is unclear. However, magnetic resonance imaging (MRI) is increasingly gaining importance for assessing both discoligamentous integrity and intraspinal condition. Both CT and MRI have direct input in classifying fractures according to the AOSpine classification.

RESULTS

Regarding fracture morphology, three main types (A-C) based on the stability are distinguished. C‑type spinal injuries are all considered unstable, irrespective of type and severity of vertebral malalignment. Injuries to the anterior and posterior ligamentous complex are also considered to interfere with stability (B-type injuries).

CONCLUSIONS

Special fracture patterns of the injured ankylosed and osteoporotic spine as well as of the pediatric lumbar spine are discussed. A survey is also given about several differential diagnoses (malignant fractures, anomalies, normal variants).