[Reconstruction after spinal fractures in the thoracolumbar region]

[Current surgical treatment concepts for traumatic thoracic and lumbar vertebral fractures in adults with good bone quality]

The surgical treatment of traumatic vertebral body fractures in patients with good bone quality is controversially discussed. The data situation is unclear and only of limited help due to mainly insufficient evidence. The surgical measures include an axially aligned reduction and an osteosynthesis which is stable under load so that immediate mobilization of the patient is possible. This requires anatomical restoration of the alignment and the biomechanical challenge of fracture healing or fusion in the correct position without relevant loss of reduction must be taken into account. The aim should be the lowest possible loss of function. In the case of existing or impending neurological deficits it is crucial to prevent deterioration of the neurological situation and to achieve the prerequisites for recovery. Posterior stabilization primarily plays the decisive role in the operative treatment. If possible, this should be a minimally invasive procedure and over short distances. For bisegmental treatment monoaxial screws and the use of index screws improve construct stability. In addition, stable cobalt rods should be used as 5mm longitudinal support. Special minimally invasive reduction instruments are helpful in restoring the sagittal and coronal relationships. The indications for an additional ventral column depend on the rigidity of the posterior stabilization, the extent of the injury of the anterior column and the intervertebral disc. Anterior fusion can often be delayed or avoided altogether, depending on the course with corresponding clinical signs.

Thoracolumbar Fractures: Comparing the Effect of Minimally Invasive Versus Open Schanz Screw Techniques on Sagittal Alignment

STUDY DESIGN

This is a retrospective comparative cohort study.

PURPOSE

This study aims to compare the effects of minimally invasive surgery (MIS) and open surgery (OS) on global sagittal alignment (GSA) in surgically managed thoracolumbar fractures.

OVERVIEW OF LITERATURE

The optimal treatment of traumatic thoracolumbar fractures (TLF) remains controversial. Both MIS techniques with polyaxial screws and OS techniques with Schanz screws have gained widespread use. The effect of each technique on the global sagittal alignment has not been reported.

METHODS

From 2014 to 2021, 22 patients with traumatic TLF underwent open posterior stabilization using an open transpedicular Schanz screw-rod construct and were compared to 15 patients who underwent minimally invasive surgery using a polyaxial percutaneous pedicle screw-rod construct. The reported radiological parameters measured on preoperative supine CT scan and immediate postop standing X-ray and on final follow-up whole spine standing X-rays included pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), preoperative segmental kyphosis (Preop-K), immediate post-operative segmental kyphosis (postop-Ki), final post-operative segmental kyphosis (postop-Kf), sagittal-vertica-axis (SVA), and spino-sacral angle (SSA).

RESULTS

The average age of the OS group was 42.5 years; 5 patients had AO type B, and 17 patients had AO type A (A3 and A4) fractures. The average follow-up was 16.8 months. The average radiological parameters were: PI = 54.9°, PI-LL = 3°, PT = 17.6°, preop-K = 16.2°, postop-Ki = 8.7°, final postop-Kf = 14.3°, SVA = 4.58 cm, and SSA = 101.8°. The average age of the MIS group was 43.4 years; 5 patients had AO type B, and 10 patients had AO type A fractures. The average follow-up was 25 months. The average radiological parameters were as follows: PI = 51°, PI-LL = 8°, PT = 18°, preop-K = 18.4°, postop-Ki = 11.6°, postop-Kf = 14.3°, SVA = 6.4 cm, SSA = 106°.

CONCLUSION

The fixation technique did not significantly affect the final correction of the local kyphosis and global spine alignment parameters.

[Minimally invasive posterior and anterior stabilization of the thoracolumbar spine after traumatic injuries]

Injuries of the thoracolumbar junction are the most common fractures of the spine due to their anatomical position and load. Common classification systems differentiate between stable and unstable injuries and thus also between operative and conservative therapy. The majority of injuries can be treated conservatively; however, unstable injuries require surgical treatment for a variety of reasons. In the grey area between stable and unstable injuries, a clinical decision based on clinical experience is necessary in order to select the best treatment. A wide variety of parameters must be included and a change in strategy from conservative to operative may also be necessary. Posterior instrumentation is the most common procedure; purely anterior stabilization is rarely used. The length of the instrumentation/spondylodesis depends on bone quality, age of the patient, and fracture. The decision as to whether anterior operative treatment should be performed depends on fracture morphology, success of reduction, and the resulting stability. The open surgical procedure is increasingly being replaced by minimally invasive procedures in posterior and anterior techniques but can be an advantage in complex injuries (B and C injuries according to AO). Hybrid procedures are also possible. This also applies to the treatment of osteoporotic fractures, since a clear assignment between traumatic and osteoporotic cause is not always easy and possible. This article describes the principles, the possible indications, and limitations of minimally invasive posterior and anterior stabilization.

Percutaneous versus open posterior stabilization in AOSpine type A3 thoracolumbar fractures

Background

The purpose of this retrospective cohort study was to compare treatment strategies of two level-one trauma centers regarding clinical and radiological outcomes focusing on non-osteoporotic AOSpine type A3 fractures of the thoracolumbar spine at levels T11 to L2.

Methods

Eighty-seven patients between 18 and 65 years of age that were treated operatively in either of two trauma centers were included. One treatment strategy includes open posterior stabilization whereas the other uses percutaneous posterior stabilization. Both included additional anterior fusion if necessary. Demographic data, McCormack classification, duration of surgery, hospital stay and further parameters were assessed. Owestry Disability Index (ODI), Visual Analog Scale (VAS) and SF-36 were measured for functional outcome. Bisegmental kyphosis angle, reduction loss and sagittal alignment parameters were assessed for radiological outcome. Follow up was at least 24 months.

Results

There was no significant difference regarding our primary functional outcome parameter (ODI) between both groups. Regarding radiological outcome kyphosis angle at time of follow up did not show a significant difference. Reduction loss at time of follow up was moderate in both groups with a significantly lower rate in the percutaneously stabilized group. Surgery time was significantly shorter for posterior stabilization and anterior fusion in the percutaneous group. Time of hospital stay was equal for posterior stabilization but shorter for anterior fusion in the open stabilized group.

Conclusion

Both treatment strategies are safe and effective showing only minor loss of reduction. Clinical relevant differences in functional and radiographic outcome between the two surgical groups could not be demonstrated.

Trial registration

It was conducted according to ICMJE guidelines and has been retrospectively registered with the German Clinical Trials Registry (identification number: DRKS00015693, 07.11.2018).

Implants for Vertebral Body Replacement - Which Systems are Available and Have Become Established

Since the first vertebral body replacement operations over 50 years ago until now, there were developed numerous methods and implants. Vertebral body replacement after corpectomy nowadays is a standard procedure in spinal surgery. At the beginning mainly bone grafts were used. Due to continuous development, PMMA and titanium implants were developed. Nowadays various expandable and non-expandable implants are available. Numerous implants can still be justified. The question arises which methods and systems are on the market and which ones have proven themselves? This article describes and compares the advantages and disadvantages of each implant type.

Monosegmental anterior column reconstruction using an expandable vertebral body replacement device in combined posterior-anterior stabilization of thoracolumbar burst fractures

INTRODUCTION

In combined posterior-anterior stabilization of thoracolumbar burst fractures, the expandable vertebral body replacement device (VBRD) is typically placed bisegmentally for anterior column reconstruction (ACR). The aim of this study, however, was to assess feasibility, outcome and potential pitfalls of monosegmental ACR using a VBRD. In addition, clinical and radiological outcome of monosegmental ACR was related to that of bisegmental ACR using the same thoracoscopic technique.

METHODS

Thirty-seven consecutive neurologically intact patients with burst fractures of the thoracolumbar junction (T11-L2) treated by combined posterior-anterior stabilization were included. Monosegmental ACR was performed in 18 and bisegmental ACR in 19 patients. Fracture type and extent of vertebral body comminution were determined on preoperative CT scans. Monosegmental and bisegmental kyphosis angles were analyzed preoperatively, postoperatively and at final radiological follow-up. Clinical outcome was assessed after a minimum of 2 years (74 ± 45 months; range 24-154; follow-up rate 89.2%) using VAS Spine Score, RMDQ, ODI and WHOQOL-BREF.

RESULTS

Monosegmental ACR resulted in a mean monosegmental and bisegmental surgical correction of - 15.6 ± 7.7° and - 14.7 ± 8.1°, respectively. Postoperative monosegmental and bisegmental loss of correction averaged 2.7 ± 2.7° and 5.2 ± 3.7°, respectively. Two surgical pitfalls of monosegmental ACR were identified: VBRD positioning (1) onto the weak cancellous bone (too far cranially to the inferior endplate of the fractured vertebra) and (2) onto a significantly compromised inferior endplate with at least two (even subtle) fracture lines. Ignoring these pitfalls resulted in VBRD subsidence in five cases. When relating the clinical and radiological outcome of monosegmental ACR to that of bisegmental ACR, no significant differences were found, except for frequency of VBRD subsidence (5 vs. 0, P = 0.02) and bisegmental loss of correction (5.2 ± 3.7° vs. 2.6 ± 2.5°, P = 0.022). After exclusion of cases with VBRD subsidence, the latter did not reach significance anymore (4.9 ± 4.0° vs. 2.6 ± 2.5°, P = 0.084).

CONCLUSIONS

This study indicates that monosegmental ACR using a VBRD is feasible in thoracolumbar burst fractures if the inferior endplate is intact (incomplete burst fractures) or features only a single simple split fracture line (burst-split fractures). If the two identified pitfalls are avoided, monosegmental ACR may be a viable alternative to bisegmental ACR in selected thoracolumbar burst fractures to spare a motion segment and to reduce the distance for bony fusion.

[Fractures of the thoracic and lumbar spine]

Fractures of the thoracic and lumbar spine result from high velocity trauma, assuming bone density is normal. The main location of fractures is the thoracolumbar junction. Most injuries can be treated conservatively; however, patients transferred to hospitals and spine centers represent a preselection with more severe trauma and a higher incidence of operative treatment. There is a large variety of operative techniques that can be used, which can be principally differentiated by the approach: posterior or anterior. Dorsal approaches are differentiated by the instrumentation for spondylodesis as open or percutaneous techniques. Minimally invasive options are favored more and more. For osteoporotic bone, cement augmented solutions may be used. Correct reduction of mainly kyphotic malalignment is crucial for the long-term outcome. Biomechanically stable reconstruction of the anterior spinal column is important mainly for the thoracolumbar junction.

When and how to operate on thoracic and lumbar spine fractures?

PURPOSE

To discuss when and how to operate on thoracic and lumbar spine fractures.

PATIENTS AND METHODS

We retrospectively studied 77 consecutive patients with thoracic and lumbar spine fractures treated from 2000 to 2011; 28 patients experienced high-energy spinal trauma and 49 low-energy spinal trauma. Mean follow-up was 5 years (1-11 years). Surgical treatment was done in 15 patients with neurological deficits, and in 16 neurologically intact patients with fractures-dislocations, burst fractures and fractures with marked deformity. Non-surgical treatment was done in 46 neurologically intact patients with simple fracture configurations. Clinical and imaging examination and the Oswestry Disability Index (O.D.I.) questionnaire were obtained.

RESULTS

All patients treated surgically maintained spinal alignment; patients with long fusion maintained the best alignment; however, they experienced back stiffness and moderate low back pain. Patients with combined posterior fusion and kyphoplasty experienced earlier recovery and improved sagittal correction. Mean O.D.I. was 22.4 and 14.2% at 3 and 12 months postoperatively. Thirty six (78%) patients treated non-surgically were asymptomatic, 22 (48%) experienced mild residual kyphosis, 10 (22 %) developed marked deformity during their follow-up and were finally operated; mean O.D.I. was 28.6 and 12.1% at 3 and 12 months. No difference in O.D.I. was observed between patients who had surgical and non-surgical treatment.

CONCLUSIONS

Progressive neurological deficits and/or mechanical instability of the spine are absolute indications for early surgical treatment. Younger patients with high-energy spinal trauma, unstable fractures and neurological deficits should be treated surgically in order to provide optimum conditions for neurologic recovery, early mobilization and possibly ambulation. Most cases can be adequately operated through a posterior only surgical approach; an anterior or combined approach is usually indicated for burst and thoracic spine fractures. Postoperative complications, more common infection and neurological deterioration may occur. Elderly, neurologically intact patients with low-energy, stable spinal fractures without marked spinal deformity may be successfully treated conservatively. Most of these patients will do well; however, follow-up for progressive posttraumatic deformity is required.

Compression and contact area of anterior strut grafts in spinal instrumentation: a biomechanical study

Background

Anterior bone grafts are used as struts to reconstruct the anterior column of the spine in kyphosis or following injury. An incomplete fusion can lead to later correction losses and compromise further healing. Despite the different stabilizing techniques that have evolved, from posterior or anterior fixating implants to combined anterior/posterior instrumentation, graft pseudarthrosis rates remain an important concern. Furthermore, the need for additional anterior implant fixation is still controversial. In this bench-top study, we focused on the graft-bone interface under various conditions, using two simulated spinal injury models and common surgical fixation techniques to investigate the effect of implant-mediated compression and contact on the anterior graft.

Methods

Calf spines were stabilised with posterior internal fixators. The wooden blocks as substitutes for strut grafts were impacted using a “pressfit” technique and pressure-sensitive films placed at the interface between the vertebral bone and the graft to record the compression force and the contact area with various stabilization techniques. Compression was achieved either with posterior internal fixator alone or with an additional anterior implant. The importance of concomitant ligament damage was also considered using two simulated injury models: pure compression Magerl/AO fracture type A or rotation/translation fracture type C models.

Results

In type A injury models, 1 mm-oversized grafts for impaction grafting provided good compression and fair contact areas that were both markedly increased by the use of additional compressing anterior rods or by shortening the posterior fixator construct. Anterior instrumentation by itself had similar effects. For type C injuries, dramatic differences were observed between the techniques, as there was a net decrease in compression and an inadequate contact on the graft occurred in this model. Under these circumstances, both compression and the contact area on graft could only be maintained at high levels with the use of additional anterior rods.

Conclusions

Under experimental conditions, we observed that ligamentous injury following type C fracture has a negative influence on the compression and contact area of anterior interbody bone grafts when only an internal fixator is used for stabilization. Because of the loss of tension banding effects in type C injuries, an additional anterior compressing implant can be beneficial to restore both compression to and contact on the strut graft.

[Fusion criteria for cages as vertebral body replacement in thoracolumbar fractures]

BACKGROUND

No commonly accepted criteria to evaluate bony incorporation of cages as vertebral body replacement in thoracolumbar fractures exist. The goal of this study was a thorough radiological evaluation of the fusion process in posterior-anterior stabilized fractures.

PATIENTS AND METHODS

In this study 35 patients were evaluated radiologically including computed tomography (CT) scanning and bone mineral density measurement inside the cages. Correction loss, cage subsidence and tilting, bone growth in and around the cages as well as bone mineral density were assessed. Fusion grading was assessed with defined criteria (i.e. bridging bone, bone growth through the cage, stability in functional X-rays and no radiolucent lines).

RESULTS

After 12 months minor subsidence and tilting of the cages had caused significant correction loss of the basal plate angle of 2.4° on average. Of the patients 20 (57%) fulfilled the criteria for complete or incomplete fusion and 5 (14%) showed no signs of bony fusion. Bone mineral density measurements were unreliable due to metallic artefacts.

CONCLUSIONS

The advocated criteria allow accurate assessment of bony incorporation of cages. Bony incorporation can be detected in and around the cages over time; however, only 57% of patients showed signs of bony fusion after 1 year.

Six-year outcome of thoracoscopic ventral spondylodesis after unstable incomplete cranial burst fractures of the thoracolumbar junction: ventral versus dorso-ventral strategy

PURPOSE

The purpose of this study is to determine the long term-results after thoracoscopic spondylodesis particularly with respect to a ventral versus dorso-ventral treatment strategy.

METHODS

In this prospective cohort study, a follow-up examination was performed in 19 patients (seven men, 12 women, average age: 37.7 years, follow-up rate: 79 %), six years after ventral thoracoscopic spondylodesis of unstable, incomplete burst fractures. Nine patients received a ventral monosegmental spondylodesis with iliac crest bone graft. The other ten cases were treated dorso-ventrally, five undergoing a ventral monosegmental treatment with iliac crest bone graft; the other five a ventral bisegmental treatment with expandable titanium cage.

RESULTS

The complication rate was 15.7 %, the rate of revision of 10.5 %. No complication was related to the ventral thoracoscopic approach, whereas all of them were related to the iliac crest bone graft. The operative bisegmental kyphotic reduction was higher in the dorso-ventrally treated group. Afterwards, the loss of reduction was similar in both study groups. The mean VAS spine score summed up to more than 80 in both groups. The mean PCS scores were comparable to a normal healthy collective of the same age.

CONCLUSIONS

The ventral thoracoscopic approach to the spine seems to be a safe therapeutic strategy. A dorso-ventral treatment concept goes along with a higher operative reduction potential.

[Osteoporotic vertebral body fractures of the thoracolumbar spine. Diagnostics and therapeutic strategies]

In cases of severe osteoporosis vertebral body fractures of the thoracolumbar spine can occur without any relevant trauma. Initially, a standardized diagnostic algorithm is recommended to detect acute vertebral body fractures and to be able to interpret the individual fracture stability. Aim of the therapy is to assure a relatively pain-free mobilization while maintaining vertebral spine alignment. A conservative therapy concept is initiated in patients with stable fractures. In cases of persistent pain, reduced mobility or increased kyphotic misalignment minimally invasive cement augmented therapy strategies are chosen. In cases of unstable fracture morphology a more complex therapy concept has to be chosen such as hybrid stabilization. A great deal of experience is needed for revision surgery. In such cases reconstructive, multi-segmental techniques might be necessary and the instrumentation should surpass the apex of kyphosis.

6-Year follow-up of ventral monosegmental spondylodesis of incomplete burst fractures of the thoracolumbar spine using three cortical iliac crest bone grafts

INTRODUCTION

Autologous bone graft is the gold standard for vertebral body replacement. Currently, after modern implants for vertebral body replacement are available, controversies exist regarding the optimal implant strategy.

PATIENTS AND METHODS

Between 2002 and 2003, 17 patients were included in this study, all suffering from incomplete burst fractures of the thoracolumbar spine. All of them were treated by ventral monosegmental spondylodesis using iliac crest bone graft. The individual treatment strategy depended on the fracture situation and patient's condition. After an average of 74 months (range 66-84) a clinical and computer tomographic follow-up examination was performed in 14 patients (average age, 35.2 years) including VAS spine score and SF 36 score. Nine patients were treated ventral only five patients dorsoventrally.

RESULTS

Complete osseous consolidation was visible in nine, partial consolidation (>30 %) in four, and lysis in one patient, without any significant differences between ventral only or dorsoventral approach. After removal of the fixateur interne the level of consolidation improved in all patients, treated dorsoventrally. There was no significant correlation between percentage of osseous consolidation and the clinical follow-up parameters. After 6 years, 71 % of the patients suffered from persistent pain associated with the approach to the iliac crest. Two revision surgeries have been necessary.

CONCLUSION

High rates of osseous consolidation are visible 6 years after ventral spondylodesis by iliac crest bone grafts. A further improvement of consolidation can be expected after dorsal implant removal. But the surgical approach to the iliac crest is accompanied with a relevant complication rate.