[Spinal column injuries in sport: treatment strategies and clinical results]

Improvement of vertebral body fracture reduction utilizing a posterior reduction tool: a single-center experience

BACKGROUND

Extensive research regarding instabilities and prevention of kyphotic malalignment in the thoracolumbar spine exists. Keystones of this treatment are posterior instrumentation and anterior vertebral height restoration. Anterior column reduction via a single-stage procedure seems to be advantageous regarding complication, blood loss, and OR-time. Mechanical elevation of the anterior cortex of the vertebra may prevent the necessity of additional anterior stabilization or vertebral body replacement. The purpose of this study was to examine (1) if increased bony reduction in the anterior vertebral cortex could be achieved by utilization of an additional reduction tool, (2) if postoperative loss of vertebral height could be reduced, and (3) if anterior column reduction is related to clinical outcome.

METHODS

From one level I trauma center, 173 patients underwent posterior stabilization for fractures of the thoracolumbar region between 2015 and 2020. Reduction in the vertebral body was performed via intraoperative lordotic positioning or by utilization of an additional reduction tool (Nforce, Medtronic). The reduction tool was mounted onto the pedicle screws and removed after tightening of the locking screws. To assess bony reduction, the sagittal index (SI) and vertebral kyphosis angle (VKA) were measured on X-rays and CT images at different time points ((1) preoperative, (2) postoperative, (3) ≥ 3 months postoperative). Clinical outcome was assessed utilizing the Ostwestry Disability Index (ODI).

RESULTS

Bisegmental stabilization of AO/OTA type A3/A4 vertebral fractures was performed in 77 patients. Thereof, reduction was performed in 44 patients (females 34%) via intraoperative positioning alone (control group), whereas 33 patients (females 33%) underwent additional reduction utilizing a mechanical reduction tool (instrumentation group). Mean age was 41 ± 13 years in the instrumentation group (IG) and 52 ± 12 years in the control group (CG) (p < 0.001). No differences in terms of gender and comorbidities were found between the two groups. Preoperatively, the sagittal index (SI) was 0.69 in IG compared to 0.74 in CG (p = 0.039), resulting in a vertebral kyphosis angle (VKA) of 15.0° vs. 11.7° (p = 0.004). Intraoperatively, a significantly greater correction of the kyphotic deformity was achieved in the IG (p < 0.001), resulting in a compensation of the initially more severe kyphotic malalignment. The SI was corrected by 0.20-0.88 postoperatively, resulting in an improvement of the VKA by 8.7°-6.3°. In the CG, the SI could be corrected by 0.12-0.86 and the VKA by 5.1°-6.6°. The amount of correction was influenced by the initial deformity (p < 0.001). Postoperatively, both groups showed a loss of correction, resulting in a gain of 0.08 for the SI and 4.1° in IG and 0.03 and 2.0°, respectively. The best results were observed in younger patients with initially severe kyphotic deformity. Considering various influencing factors, clinical outcome determined by the ODI showed no significant differences between both groups.

CONCLUSION

Utilization of the investigated reduction tool during posterior stabilization of vertebral body fractures in a suitable collective of young patients with good bone quality and severe fracture deformity may lead to better reduction in the ventral column of the fractured vertebral body and angle correction. Therefore, additional anterior stabilization or vertebral body replacement may be prevented.

[Winter sports injuries of the thoracic and lumbar spine : Etiology, classification and stage-specific therapy]

BACKGROUND

Overall, spinal injuries in winter sports are extremely rare. The incidence is given as approximately 0.01/1000 ski days. While falls and collisions at high speed are the main concerns for skiers, spinal injuries for snowboarders occur primarily on landing after a jump. The age of a typical spinally injured skier is 40, which is older than that of the average snowboarder at 23.

CLASSIFICATION

Primarily, the thoracolumbar junction is injured and hereby mainly anterior compression fractures (type A1) and burst fractures (types A3 and A4) occur. Injuries caused by flexion or distraction mechanisms (Type B) or rotation injuries (Type C) are less common. Injuries to the cervical spine are rare overall, but they are also represented in the very few cases with neurological deficits.

THERAPY

With appropriate X‑ray diagnostics, including CT and, if necessary, MRI, the appropriate therapy can be initiated so that a return to sport is possible in most cases. Furthermore, there is ongoing scientific discussion as to when conservative therapy is superior and when surgery is superior.

The effect of posterior compression of the facet joints for initial stability and sagittal profile in the treatment of thoracolumbar fractures: a biomechanical study

PURPOSE

Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile.

METHODS

Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression.

RESULTS

We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state.

CONCLUSION

Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies.

The Conservative Treatment of Traumatic Thoracolumbar Vertebral Fractures

BACKGROUND

The conservative treatment of traumatic thoracolumbar vertebral fractures is often not clearly defined.

METHODS

This review is based on articles retrieved by a systematic search in the PubMed and Web of Science databases for publications up to February 2018 dealing with the conservative treatment of traumatic thoracolumbar vertebral fractures. The search initially yielded 3345 hits, of which 35 were suitable for use in this review.

RESULTS

It can be concluded from the available original clinical research on the subject, including three randomized controlled trials (RCTs), that the primary diagnostic evaluation should be with plain x-rays, in the standing position if possible. If a fracture is suspected on the plain films, computed tomography (CT) is indicated. Magnetic resonance imaging (MRI) is additionally advisable if there is a burst fracture. The spinal deformity resulting from the fracture should be quantified in terms of the Cobb angle. The choice of a conservative or operative treatment strategy is based on the primary stability of the fracture, the degree of deformity, the presence or absence of disc injury, and the patient's clinical state. Our analysis of the three RCTs implies that early functional therapy without a corset should be performed, although treatment in a corset may be appropriate to control pain. Follow-up x-rays should be obtained after mobilization and at one week, three weeks, six weeks, and twelve weeks.

CONCLUSION

Further comparative studies of the indications for surgery and specific conservative treatment modalities would be desirable.

Biomechanical comparison of the end plate design of three vertebral body replacement systems

INTRODUCTION

Compression fractures at the thoracolumbar junction are frequently treated by reconstruction with vertebral body replacement systems. Modern cage implants have been developed which respect the anatomy and angulation of the adjacent bony endplates. The objective of this study was to investigate the biomechanical performance of anatomic endplate design and variable endplate angulation.

MATERIALS AND METHODS

Three cage systems [Hydrolift (HYL), Aesculap; Synex II (SYN), Synthes; Obelisc (OBC), Ulrich] were compared employing a composite bone substitute material at two levels of endplate angulation (0°, 3°). Their load-bearing capacity was assessed in a physiologic test with human vertebral specimens in a misalignment situation (3°). The HYL and SYN offered anatomically shaped endplates. The endplates of the HYL had variable angulation during insertion and were then mechanically fixated. The OBC had fixed and circular endplates. The load to failure and system stiffness were evaluated by an axial compression test. The bone mineral density (BMD) and the area of the bony endplates were measured via CT.

RESULTS

None of the mechanical properties differed between 0° and 3° for the HYL cage using bone substitute material, while the OBC lost 19% of the failure load (p = 0.001) and 55% of stiffness (p = 0.001) in case of misalignment. In human bone specimens, failure loads were comparable among all implants (p > 0.1) with the HYL showing the largest system stiffness (p < 0.05). Furthermore, a strong correlation between stiffness and BMD (R(2) = 0.82) and failure load and BMD (R(2) = 0.87) was found.

CONCLUSION

Anatomically shaped and continuously variable endplates provide mechanical advantages under imperfect alignment and may thus reduce secondary dislocation and the loss of correction. This is achieved by retaining an optimal contact area between the implant and the bony endplates. Conventional cage design with circular endplates offer adequate stability in optimal contact situations.

The morbidity of open transthoracic approach for anterior scoliosis correction

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the patient satisfaction and the patients' perceived approach-related morbidity (ArM) after open thoracotomy (OTC) for instrumented anterior scoliosis surgery.

SUMMARY OF BACKGROUND DATA

There is no mid- to long-term data on the patients' perceived ArM concerning chest wall dissection for open anterior scoliosis correction.

METHODS

A specific questionnaire was used to retrospectively evaluate mid- to long-term follow-up data concerning ArM after OTC of patients younger than 30 years (range, 11-28 years) who underwent anterior open transthoracic scoliosis surgery. The questionnaire was comprised of detailed scar-related questions. Applying strict inclusion criteria, we could analyze outcomes in terms of percentage morbidity (morbidity [%]) of 40 patients who underwent OTC for instrumented scoliosis correction.

RESULTS

Mean age of the patients was 16 ± 3.8 years, follow-up was 61.5 ± 72.6 months on average, and mean incision length was 25.7 ± 3.1 cm. Mean number of levels fused was 5.9 ± 1.5. Single thoracotomy was performed in 25 patients and a thoracoabdominal approach in 15 patients. Mean morbidity (0%, not delineating no ArM; 100%, delineating highest ArM) was 5.4% ± 11.3%; 47.5% of patients had no morbidity; 12.5% had morbidity >10% (mean: 28.5%). Signs of intercostal neuralgia (ICN) were present in 10%. Patients judged their clinical outcome as "good" in 20% and "excellent" in 80%. Statistical analysis did not reveal differences in outcomes and percentage morbidity concerning age of patients, extent of approach (thoracotomy vs. thoracoabdominal approach) and incision length, gender, or follow-up length. However, the presence of ICN had a significant effect on the outcome, showing high correlation with increased morbidity (P < 0.0001). In the clinical judgment of outcomes, the severity of the ArM after OTC was mild, except for 2 patients who had moderate approach and scar-related morbidity.

CONCLUSION

ArM after open thoracic spinal surgery or thoracoscopic procedures can be assessed using the questionnaire. The current study showed that ArM in young patients who underwent OTC for anterior instrumented scoliosis correction was low. Patients with increased signs of ICN did worse in terms of the questionnaire survey. The study showed that neither cosmesis nor scar-related problems were a concern for patients undergoing OTC.