Sagittale Balance und posttraumatische Fehlstellungen der Brust- und Lendenwirbelsäule. Teil 1

[Surgical challenges with spinal balance in adult spinal deformities-the forgotten coronal plane]

This article gives a brief overview of the importance, planning and correction of coronal spinal imbalance in patients with adult and pediatric spinal deformity.

An explorative, biomechanical analysis of spine motion during out-of-hospital extrication procedures

OBJECTIVES

The extrication of patients following a road traffic collision is among the basic procedures in emergency medicine. Thus, extrication is a frequently performed procedure by most of the emergency medical services worldwide. The appropriate extrication procedure depends on the patient's current condition and accompanying injuries. A rapid extrication should be performed within a few minutes, and the cervical spine (at least) should be immobilized. To our knowledge, the scientific literature and current guidelines do not offer detailed recommendations on the extrication of injured patients. Thus, the aim of the current study is to compare the effectiveness of spinal stabilization during various out-of-hospital extrication procedures.

METHODS

This is an explorative, biomechanical analysis of spine motion during different extrication procedures on an example patient. Movement of the cervical spine was measured using a wireless human motion tracker. Movement of the thoracic and lumbar spine was quantified with 12 strain gauge sensors, which were positioned paravertebrally on both sites along the thoracic and lumbar spine. To interpret angular movement, a motionscore was developed based on newly defined axioms on the biomechanics of the injured spine.

RESULTS

Self-extrication showed the least spinal movement (overall motionscore sum = 667). Movement in the cervical spine could further be reduced by applying a cervical collar. The extrication by a rescue boa showed comparable results in overall spinal movement compared to the traditional extrication via spineboard (overall motionscore sum = 1862vs. 1743). Especially in the cervical spine, the spinal movement was reduced (motionscore sum = 339 vs. 595). However, the thoracic spine movement was increased (motionscore sum = 812 vs. 432).

CONCLUSION

In case of a suspected cervical spine injury, guided self-extrication seems to be the best option. If the patient is not able to perform self-extrication, using a rescue boa might reduce cervical spinal movement compared to the traditional extrication procedure. Since promising results are shown in the case of extrication using a patient transfer sheet that has already been placed below the driver, future developments should focus on novel vehicle seats that already include an extrication device.

[Biomechanical aspects of preoperative planning: What is really important?]

BACKGROUND

Sagittal balance is dependent on a complex interplay of the spinal curves, shape and setting of the pelvis, but also the position of the joints of the lower limb. Degenerative processes such as stiffening of the spine, aging of musculature, or reduction of the range of motion of the joints lead to imbalance of the spine after all compensatory mechanisms have been exhausted.

OBJECTIVES

Based on standardized imaging, compensation mechanisms must be identified within a biomechanical analysis of the spine, the original sagittal spine profile anticipated and included in the planning of the corrective intervention.

RESULTS

This review presents the most important global and spinopelvic parameters for the biomechanical analysis of the spine. In addition, normal variations of the sagittal alignment are discussed, compensation mechanisms are shown, and the planning of the rebalancing of the sagittal alignment is shown according to the full balance integrated model.

Radiological Results and Clinical Patient Outcome After Implantation of a Hydraulic Expandable Vertebral Body Replacement following Traumatic Vertebral Fractures in the Thoracic and Lumbar Spine: A 3-Year Follow-Up

STUDY DESIGN

A prospective monocentric study.

OBJECTIVE

The aim of the current study was the analysis of patient outcome and radiological results 3 years after implantation of a hydraulic expandable vertebral body replacement (VBR) system.

SUMMARY OF BACKGROUND DATA

Around 70% to 90% of all traumatic spinal fractures are located in the thoracic and lumbar spine. Dorso-ventral stabilization is a frequently used procedure in traumatic vertebral body fracture treatment. VBR systems can be used to bridge bony defects. In the current study, a new VBR expanded by water pressure with adjustable endplates is used.

METHODS

All patients who suffered a singular traumatic fracture to a thoracic or lumbar vertebral body (Th 5-L 5) in the period from November 2009 to December 2010 and (i) underwent dorsal instrumentation and (ii) afterwards received the implantation of a hydraulic VBR were included in this study. The clinical outcome (visual analogue scale [VAS] spine score, questionnaire) and radiological findings (sagittal angle, implant subsidence, and implant position) 3 years after implantation were analyzed.

RESULTS

The follow-up was successful for n = 47 patients (follow-up rate: 89%). Most of the patients (n = 40) were "generally/very satisfied" with their outcome. The mean rating of the VAS spine score was 65.2 ± 23.1 (range: 20.5-100.0). The analysis of the radiological data showed an average subsidence of the implants of 1.1 ± 1.2 mm (range 0.0-5.0 mm). After the initial operation, the local sagittal angle remained stable in the follow-up 3 years later both for the thoracic spine and lumbar spine. Furthermore, no change in the implant's position was observed.

CONCLUSION

The implantation of a hydraulically expandable VBR allows a permanent stable fixation after traumatic fractures of the thoracic and lumbar spine.

LEVEL OF EVIDENCE

2.

[Trisegmental fusion by vertebral body replacement : Outcome following traumatic multisegmental fractures of the thoracic and lumbar spine]

BACKGROUND

Around 5% of all trauma patients suffer from spinal trauma. Spinal fractures are mainly located in the thoracic and lumbar spine. For multisegmental vertebral fractures categorized as instable, combined dorsal instrumentation and ventral stabilization is recommended. Numerous vertebral body replacement systems are available for ventral stabilization.

OBJECTIVES

The aim of the current study was to analyze radiological results following the implantation of a hydraulic expandable vertebral body replacement and the evaluation of patients' outcome three years after implantation.

MATERIALS AND METHODS

All patients who suffered traumatic multisegmental fractures of the thoracic or lumbar spine in the period from September 2009 to September 2012 were included in this study. Patients with additional injuries or abnormal sensitivity or motor function were excluded from the current study. All patients underwent dorsal percutaneous instrumentation. Afterwards, implantation of the vertebral body replacement was performed via the mini-open approach at our level I trauma center. In the computed tomography and X‑ray imaging, the sagittal kyphotic angle was measured. Furthermore, the clinical outcome (patients' satisfaction, VAS spine score) was analyzed using a questionnaire.

RESULTS

During the above mentioned period, seven patients (four female; three male) underwent dorsal instrumentation and ventral trisegmental fusion and were identified fitting the inclusion/exclusion criteria and thus could be included in the study. Most fractures were located in the thoracic-lumbar junction and were categorized A4 according to the AO Spine classification system. The analysis of the radiological data showed a pre-operative average traumatic segmental angle of 18.1 ± 14.9°, which could be decreased by reposition procedure to 6.4 ± 1.7°. The complete follow-up, including the data three years after implantation of the vertebral body implant, was available for three patients. The traumatic segmental angle remained stable in the follow-up three years later. In one case, a subsidence of the implant of 1.5 mm was observed, having no influence on the patients' satisfaction. All three patients indicated to be very satisfied with their outcome. The VAS spine score rating was in the range between 62.4 and 70.2.

CONCLUSIONS

The current study shows that in the case of multisegmental fractures complete reposition by ligamentotaxis and by the percutaneous instrumentation system is possible. In addition to the percutaneous dorsal instrumentation, the implantation of a hydraulically expandable vertebral body replacement may allow a stable fusion after complex traumatic fractures of the thoracic and lumbar spine. Patients are very satisfied with their outcome after this procedure.