Transpedicular vertebral body augmentation reinforced with pedicle screw fixation in fresh traumatic A2 and A3 lumbar fractures: comparison between two devices and two bone cements

Treating traumatic thoracolumbar spine fractures using minimally invasive percutaneous stabilization plus balloon kyphoplasty: a 102-patient series

BACKGROUND

There is no consensus on the treatment for spinal injuries resulting in thoracolumbar fractures without neurological impairment. Many trauma centers are opting for open surgery rather than a neurointerventional approach combining posterior percutaneous short fixation (PPSF) plus balloon kyphoplasty (BK).

OBJECTIVE

To assess the safety and efficacy of PPSF+BK and to estimate the expected improvement by clarifying the factors that influence improvement.

METHODS

We retrospectively reviewed patients who underwent PPSF+BK for the treatment of single traumatic thoracolumbar fractures from 2007 to 2019. Kyphosis, loss of vertebral body height (VBH), clinical and functional outcomes including visual analog scale and Oswestry disability index were assessed. We examined the overall effects in all patients by constructing a linear statistical model, and then examined whether efficacy was dependent on the characteristics of the patients or the fractures.

RESULTS

A total of 102 patients were included. No patient experienced neurological worsening or wound infections. The average rates of change were 74.4% (95% CI 72.6% to 76.1%) for kyphosis and 85.5% (95% CI 84.4% to 86.6%) for VBH (both p<0.0001). The kyphosis treatment was more effective on Magerl A3 and B2 fractures than on those classified as A2.3, as well as for fractures with slight posterior wall protrusion on the spinal canal. A higher postoperative visual analog scale score was predictive of poorer outcome at 1 year.

CONCLUSIONS

This is the largest series reported to date and confirms and validates this surgical treatment. All patients exhibited improved kyphosis and restoration of VBH. We advise opting for this technique rather than open surgery.

A Hybrid Uniplanar Pedicle Screw System with a New Intermediate Screw for Minimally Invasive Spinal Fixation: A Finite Element Analysis

Purpose

A hybrid pedicle screw system for minimally invasive spinal fixation was developed based on the uniplanar pedicle screw construct and a new intermediate screw. Its biomechanical performance was evaluated using finite element (FE) analysis.

Methods

A T12-L2 FE model was established to simulate the L1 vertebral compression fracture with Magerl classification A1.2. Six fixation models were developed to simulate the posterior pedicle screw fracture fixation, which were divided into two subgroups with different construct configurations: (1) six-monoaxial/uniplanar/polyaxial pedicle screw constructs and (2) four-monoaxial/uniplanar/polyaxial pedicle screw constructs with the new intermediate screw. After model validation, flexion, extension, lateral bending, and axial rotation with 7.5 Nm moments and preloading of 500 N vertical compression were applied to the FE models to compare the biomechanical performances of the six fixation models with maximum von Mises stress, range of motion, and maximum displacement of the vertebra.

Results

Under four loading scenarios, the maximum von Mises stresses were found to be at the roots of the upper or lower pedicle screws. In the cases of flexion, lateral bending, and axial rotation, the maximum von Mises stress of the uniplanar screw construct lay in between the monoaxial and polyaxial screw constructs in each subgroup. Considering lateral bending, the uniplanar screw construct enabled to lower the maximum von Mises stress than monoaxial and polyaxial pedicle screw constructs in each subgroup. Two subgroups showed comparable results of the maximum von Mises stress on the endplates, range of motion of T12-L1, and maximum displacement of T12 between the corresponding constructs with the new intermediate screw or not.

Conclusions

The observations shown in this study verified that the hybrid uniplanar pedicle screw system exhibited comparable biomechanical performance as compared with other posterior short-segment constructs. The potential advantage of this new fixation system may provide researchers and clinical practitioners an alternative for minimally invasive spinal fixation with vertebral augmentation.

Clinical, radiological, and patient-reported outcomes 13 years after pedicle screw fixation with balloon-assisted endplate reduction and cement injection

PURPOSE

In management of traumatic thoracolumbar burst fractures, short-segment pedicle screw fixation with balloon-assisted endplate reduction (BAER) and cement injection is a safe, feasible, and effective technique to maintain radiological alignment with minimum spinal segments involved. However, 20% of patients report daily discomfort despite good spinal alignment and fusion after this technique. This study provides clinical, radiological, and patient-reported outcomes after a minimum 13 years of follow-up.

METHODS

Eighteen patients were invited at the outpatient clinic for clinical/radiological examinations. The cohort (originally 20 patients) was treated 13-14 years earlier with pedicle screw fixation, BAER, and cement injection for traumatic thoracolumbar burst fractures. Patient-reported outcome measures were obtained at time of examinations. Current data were compared with data obtained at 6 years of follow-up.

RESULTS

Seventeen patients (median age 50; range 32-80) cooperated. No/minimal back pain was reported by 15 patients, and 12 patients returned to their previous heavy labor work. Median visual analog score of health (80%; 50-100%) was similar to results at 6 years (80%; 60-100% p = 0.259). An Oswestry Disability Index score of less than 20% (reflecting minimal disability) was reported by 14 patients, compared with 15 patients at 6 years of follow-up. No significant differences were found in wedge or Cobb angle between the time points. Intravertebral cement resorption was not observed.

CONCLUSION

Results from this study suggest that, 13 years after pedicle screw fixation with BAER and cement injection for traumatic thoracolumbar burst fractures, functional performance, pain and radiological outcomes of the current cohort were stable or had slightly improved. These slides can be retrieved under Electronic Supplementary Material.

Percutaneous Injection of Strontium Containing Hydroxyapatite versus Polymethacrylate Plus Short-Segment Pedicle Screw Fixation for Traumatic A2- and A3/AO-Type Fractures in Adults

Introduction

Polymethacrylate (PMMA) is commonly used in vertebroplasty and balloon kyphoplasty, but its use has been associated with complications. This study tests three hypotheses: (1) whether strontium hydroxyapatite (Sr-HA) is equivalent to PMMA for restoring thoracolumbar vertebral body fractures, (2) whether the incidence of PMMA leakage is similar to that of Sr-HA leakage, and (3) whether Sr-HAis is resorbed and substituted by new vertebral bone.

Materials and Methods

Two age- and sex-matched groups received short percutaneous pedicle screw fixation plus PEEK implant (Kiva, VCF Treatment System, Benvenue Medical, Santa Clara, CA, USA) filled with either Sr-HA (Group A) or PMMA (Group B) after A2- and A3/AO-type thoracolumbar vertebral body fractures. The Visual Analog Scale (VAS) score and imaging parameters, which included segmental kyphosis angle (SKA), vertebral body height ratios (VBHr), spinal canal encroachment (SCE), bone cement leakage, and Sr-HA resorption, were compared between the two groups.

Results

The average follow-up was 28 months. No differences in VAS scores between Groups A and B were observed at baseline. Baseline back pain in both groups improved significantly three months postoperatively. Anterior, middle, and posterior VBHr did not differ between the two groups at any time point. SKA was improved insignificantly in both groups. SCE decreased insignificantly in both groups on 12-month follow-up using computed tomography (CT). PMMA leakage was observed in one patient, while no Sr-HA paste leakages occurred. Sr-HA resorption and replacement with vertebral bone were observed, and no new fractures were observed.

Conclusions

As all hypotheses were confirmed, the authors recommend the use of Sr-HA instead of PMMA in traumatic spine fractures, although more patients and longer follow-up will be needed to strengthen these results. This trial is registered with NCT03431519.

Post-operative bracing after pedicle screw fixation for thoracolumbar burst fractures: A cost-effectiveness study

PURPOSE

While frequently prescribed to patients following fixation for spine trauma, the utility of spinal orthoses during the post-operative period is poorly described in the literature. In this study, we calculated rates of reoperation and performed a decision analysis to determine the utility of bracing following pedicle screw fixation for thoracic and lumbar burst fractures.

METHODS

Pubmed was searched for articles published between 2005 and 2015 for terms related to pedicle screw fixation of thoracolumbar fractures. Additionally, a database of neurosurgical patients operated on within the authors institution was also used in the analysis. Incidences of significant adverse events (wound revision for either dehiscence or infection or re-operation for non-union or instability due to hardware failure) were determined. Pooled means and variances of reported parameters were obtained using a random-effects, inverse variance meta-analytic model for observational data. Utilities for surgical outcome and complications were assigned using previously published values.

RESULTS

Of the 225 abstracts reviewed, 48 articles were included in the study, yielding a total of 1957 patients. After including patients from the institutional registry, together a total of 2081 patients were included in the final analysis, 1328 of whom were braced. Non-braced patients were older then braced patients, although this only approached significance (p=0.051). Braced patients had significantly lower rates of re-operation for non-union or clinically significant hardware failure (1.3% vs. 1.8%, p<0.001) although the groups had comparable rates of operative wound dehiscence and infection (p=1.000). These two approaches yielded comparable utility scores (p=0.120). Costs between braced and non-braced patients were comparable excluding the cost of the brace (p=0.256); hence, the added cost of the brace suggests that bracing post-operatively is not a cost effective measure.

CONCLUSIONS

Bracing following operative stabilization of thoracolumbar fracture does not significantly improve stability, nor does it increase wound complications. Moreover, our data suggests that post-operative bracing may not be a cost-effective measure.

Transpedicular bone grafting and pedicle screw fixation in injured vertebrae using a paraspinal approach for thoracolumbar fractures: a retrospective study

Background

Complications in posterior pedicle screw fixation using a conventional posterior approach for thoracolumbar fractures include vertebral height loss, kyphosis relapse and breakage, or loosening of instrumentation. The purpose of this study was to evaluate the clinical effects of transpedicular bone grafting and pedicle screw fixation in injured vertebrae using a paraspinal approach for thoracolumbar fractures.

Methods

We retrospectively analyzed 50 patients with thoracolumbar fractures treated with transpedicular bone grafting and pedicle screw fixation in injured vertebrae using a paraspinal approach. Operative time, blood loss, visual analog scale (VAS) scores for back pain, and the relative height and Cobb angle of the fractured vertebrae were measured.

Results

The average operative time was 71.8 min, and the blood loss was 155 ml. Postoperative VAS scores were significantly lower than preoperative scores (P = 0.08), but there was no difference between 1 week and 1 year postoperatively (P = 0.18). The postoperative relative heights of the fractured vertebrae were higher than the preoperative heights (P = 0.001, 0.005, 0.001), but there were no differences between 1 week and 1 or 2 years postoperatively (P = 0.24/0.16). The postoperative Cobb angles were larger than the preoperative angles (P = 0.002, 0.007, 0.001), but there were no differences between 1 week and 1 or 2 years postoperatively (P = 0.19/0.23).

Conclusions

Transpedicular bone grafting and pedicle screw fixation in injured vertebrae using a paraspinal approach for thoracolumbar fractures achieved satisfactory results and can restore vertebral height, increase the stability of the anterior and middle columns of injured vertebrae, and decrease the risk of back pain.

Percutaneous pedicle screw fixation plus kyphoplasty for thoracolumbar fractures A2, A3 and B2

DESIGN

Retrospective cohort.

PURPOSE

The aim of this study is to evaluate the effectiveness of percutaneous short fixation (PSFx) plus kyphoplasty (BP) for thoracolumbar fractures.

METHODS

Thirty-six consecutive selected patients, aged 59 ± 17 years, with fresh single thoracolumbar A₂, A₃, and B₂ AO-type fracture, received PSFx plus BP. The primary outcomes pain, and vertebral body deformity; and the secondary outcomes screw malposition, facet violation, PMMA leakage, adjacent segment degeneration (ASD) and loss of correction were evaluated. The f/up was 31 ± 7 months.

RESULTS

Pain and kyphosis decreased and vertebral body heights increased significantly postoperation. PMMA leakage occurred in five cases; 6 (4 %) screws were grades III malpositioned in relation to pedicle; facet violation occurred in 8 (5.5 %) facets; loss of kyphosis correction was 3.68°; ASD occurred in two cases; interfacet fusion in ten (28 %) patients; Three patients were reoperated for different reasons.

CONCLUSIONS

PSFx plus BP for thoracolumbar fractures reduces significantly spinal deformity and pain with few complications.

Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model

Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications.

Bony healing of unstable thoracolumbar burst fractures in the elderly using percutaneously applied titanium mesh cages and a transpedicular fixation system with expandable screws

INTRODUCTION

There is a high incidence of vertebral burst fractures following low velocity trauma in the elderly. Treatment of unstable vertebral burst fractures using the same principles like in stable vertebral burst fractures may show less favourable results in terms of fracture reduction, maintenance of reduction and cement leakage. In order to address these shortcomings this study introduces cementless fixation of unstable vertebral burst fractures using internal fixators and expandable intravertebral titanium mesh cages in a one-stage procedure via minimum-invasive techniques.

MATERIAL AND METHODS

A total of 16 consecutive patients (median age 76 years, range 58-94) with unstable thoracolumbar burst fractures and concomitant osteoporosis were treated by an internal fixator inserted via minimum invasive technique one level above and below the fractured vertebra. Fracture reduction was achieved and maintained by transpedicular placement of two titanium mesh cages into the fractured vertebral body during the same procedure. Intra- and postoperative safety of the procedure as well as analysis of reduction quality was analysed by 3D C-arm imaging or CT, respectively. Clinical and radiographic follow-up averaged 10.4 months (range 4.5-24.5).

RESULTS

Stabilization of the collapsed vertebral body was achieved in all 16 cases without any intraoperative complication. Surgical time averaged 102 ± 6.6 minutes (71-194). The postoperative kyphotic angle (KA) and Cobb angle revealed significant improvements (KA 13.7° to 7.4°, p < 0.001; Cobb 9.6° to 6.0°, p < 0.002) with partial loss of reduction at final follow-up (KA 8.3°, Cobb 8.7°). VAS (Visual Analogue Scale) improved from 7.6 to 2.6 (p < 0.001). Adjacent fractures were not observed. One minor (malposition of pedicle screw) complication was encountered.

CONCLUSION

Cementless fixation of osteoporotic burst fractures revealed substantial pain relief, adequate maintenance of reduction and a low complication rate. Bony healing after unstable osteoporotic burst fractures is possible.

TRIAL REGISTRATION

www.germanctr.de DRKS00005657.

Intrabody application of eptotermin alpha enhances bone formation in osteoporotic fractures of the lumbar spine; however, fails to increase biomechanical stability - results of an experimental sheep model

This study analyses the effect of eptotermin α application into fractured vertebrae. It is hypothesized that eptotermin α is capable to enhance bony healing of the osteoporotic spine. In 10 Merino sheep osteoporosis induction was performed by ovariectomy, corticosteroid therapy and calcium/phosphorus/vitamin D-deficient diet; followed by standardized creation of lumbar vertebral compression fractures (VCFs) type A3.1 and consecutive fracture reduction/fixation using expandable mesh cages. Randomly, intravertebral eptotermin α (G1) or no augmentation was added (G2). Macroscopic, micro-CT, and biomechanical evaluation assessed bony consolidation two months postoperatively: Micro-CT data revealed bony consolidation for all cases with significant increased callus development for G2 (60%) and BV/TV (bone volume/total volume 73.45%, osteoporotic vertebrae 35.76%). Neither group showed improved biomechanical stability. Eptotermin α enhanced mineralisation in VCFs in an experimental setup with use of cementless augmentation via an expandable cage. However, higher bone mineral density did not lead to superior biomechanical properties.