Radiological and mid- to long-term patient-reported outcome after stabilization of traumatic thoraco-lumbar spinal fractures using an expandable vertebral body replacement implant

Background

For the treatment of unstable thoraco-lumbar burst fractures, a combined posterior and anterior stabilization instead of a posterior-only instrumentation is recommend in the current literature due to the instability of the anterior column. Data on restoring the bi-segmental kyphotic endplate angle (BKA) with expandable vertebral body replacements (VBR) and on the mid- to long-term patient-reported outcome measures (PROM) is sparse.

Methods

A retrospective cohort study of patients with traumatic thoraco-lumbar spinal fractures treated with an expandable VBR implant (Obelisc™, Ulrich Medical, Germany) between 2001 and 2015 was conducted. Patient and treatment characteristics were evaluated retrospectively. Radiological data acquisition was completed pre- and postoperatively, 6 months and at least 2 years after the VBR surgery. The BKA was measured and fusion-rates were assessed. The SF-36, EQ-5D and ODI questionnaires were evaluated prospectively.

Results

Ninety-six patients (25 female, 71 male; age: 46.1 ± 12.8 years) were included in the study. An AO Type A4 fracture was seen in 80/96 cases (83.3%). Seventy-three fractures (76.0%) were located at the lumbar spine. Intraoperative reduction of the BKA in n = 96 patients was 10.5 ± 9.4° (p < 0.01). A loss of correction of 1.0 ± 2.8° at the first follow-up (t1) and of 2.4 ± 4.0° at the second follow-up (t2) was measured (each p < 0.05). The bony fusion rate was 97.9%. The total revision rate was 4.2%. Fifty-one patients (53.1% of included patients; age: 48.9 ± 12.4 years) completed the PROM questionnaires after 106.4 ± 44.3 months and therefore were assigned to the respondent group. The mean ODI score was 28.2 ± 18.3%, the mean EQ-5D VAS reached 60.7 ± 4.1 points. Stratified SF-36 results (ISS < and ≥ 16) were lower compared to a reference population.

Conclusion

The treatment of traumatic thoraco-lumbar fractures with an expandable VBR implant lead to a high rate of bony fusion. A significant correction of the BKA could be achieved and no clinically relevant loss of reduction occurred during the follow-up. Even though health related quality of life did not reach the normative population values, overall satisfactory results were reported.

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.

Combined anteroposterior fixation using a titanium cage versus solely posterior fixation for traumatic thoracolumbar fractures: A systematic review and meta-analysis

Study Design:

Systematic review with meta-analysis.

Objective:

Additional anterior stabilization might prevent posterior implant failure, but over time, the disadvantageous of bone grafts have become evident. The objective of this systematic review was to compare risks and advantages of additional anterior stabilization with a titanium cage to solely posterior fixation for traumatic thoracolumbar fractures.

Methods:

An electronic search was performed in the literature from 1980 to March 2016. Studies comparing only posterior with anteroposterior fixation by means of a titanium cage were included in this study. Data extraction and Cochrane risk of bias assessment were done by two independent authors. In addition, the PRISMA statement was followed, and the GRADE approach was used to present results.

Results:

Of the 1584 studies, two randomized controlled trials (RCTs) and one retrospective cohort study were included in the meta-analysis. The RCTs reported evidence of high quality that anteroposterior stabilization maintained better kyphosis correction than posterior stabilization alone. However, these results were neutralized in the meta-analysis by the cohort study. Implant failure was reported by one study, in the posterior group. No differences in follow-up visual analog scale scores, neurologic improvement, and complications were found. Operation time, blood loss, and hospital stay all increased in the anteroposterior group.

Conclusions:

Patients with a highly comminuted or unstable fracture could benefit from combined anteroposterior stabilization with a titanium cage, for some evidence suggests this prevents loss of correction. However, large randomized studies still lack. There is a risk of cage subsidence, and increased perioperative risks have to be considered when choosing the optimal treatment.

Spinal fracture reduction with a minimal-invasive transpedicular Schanz Screw system: clinical and radiological one-year follow-up

INTRODUCTION

Surgical management of thoracolumbar trauma involves correction of posttraumatic deformity and placement of transpedicular instrumentation. The aim of this prospective cohort study was to generate first results reflecting the clinical and radiological outcome of patients treated with percutaneous dorsal instrumentation for fractures of the thoracic and lumbar spine with the use of a transpedicular new Schanz Screw system (USS Fracture MIS, DePuy Synthes).

METHODS

A total of 26 patients with fractures of the thoracic and lumbar spine were operatively treated with bi-segmental dorsal instrumentation between January and December 2012. Radiological data acquisition was performed pre- and postoperatively, after six weeks, three, six, and twelve months. The radiological parameter of interest was the bi-segmental kyphotic end plate angle (Cobb angle). The Chronic Disability Index (CDI), the Oswestry Disability Index (ODI), and the Spine Tango Core Outcome Measurement Index (COMI) were applied to investigate the clinical outcome.

RESULTS

The clinical follow-up was completed by 22 patients (84.6%), and the radiological follow-up by 21 (80.8%) patients. Our patient population had a mean age of 47.4 ± 4.1 years. Twelve patients received dorsal instrumentation, and 14 patients were treated with an additional ventral reconstruction. Intraoperative reduction was 11.5 ± 1.5° among all patients (p < 0.01). A considerable amount of the operative correction was lost after six weeks with a loss of reduction of 4.6 ± 1.4° (p < 0.01). At one year follow-up, the measured loss of reduction was significant in comparison to the postoperative state, 6.9 ± 1.3° among all patients, 8.7 ± 2.1° after dorsal and 4.9 ± 1.1° after dorsoventral stabilisation (all p < 0.01). Moreover, all patients had minimal to moderate disability with a CDI of 1.8 ± 0.4 (0 - 7), and an ODI of 15.6 ± 3.6 (0 - 60).

CONCLUSION

The new transpedicular Schanz screw system can deliver a correction and stabilization of thoracic and lumbar spine fractures. Patients report minimal to moderate disability as a result of their severe injury one year after trauma. We advocate the use of the transpedicular Schanz screw system to correct posttraumatic kyphotic deformity, with secondary anterior fusion in our treatment strategy of thoracolumbar incomplete burst fractures in patients without a neurologic deficit.

Comparison of biomechanical properties of single- and two-segment fusion for Denis type B spinal fractures

OBJECTIVE

To compare the biomechanical properties of single- and two-segment fusion for Denis type B spinal fracture.

METHODS

Two female patients with Denis type B L1 vertebral fractures were studied. Both patients had achieved intervertebral fusion by 1 year postoperatively, at which time CT data were collected, including data of one patient before and after removal of pedicle screws and of another whose pedicle screws were not removed. The data were imported into Mimics software and T11 -L2 three dimensional models established. After construction of the models, they were imported into ANSYS software. An axial load (260 N) and 10 Nm torque were loaded to simulate the flexion, extension, lateral bending and rotation of the spine, respectively.

RESULTS

There was no significant difference in the average displacement of the spine motion between the two-segment and single-segment fusion patients without removal of pedicle screws. However, for all motion forms, the average displacement of the single-segment fusion patient' spine after removal of pedicle screws was significantly greater than that before removal of pedicle screws and that of the two-segment fusion patient. The average Von Mises stress of T11-12 intervertebral disc of two-segment fusion patient was significantly greater than that of the one-segment fusion patient. Moreover, the average Von Mises stress of T11-12 intervertebral disc of single-segment fusion patient was greater before than after removal of pedicle screws.

CONCLUSION

Provided there is satisfactory interbody fusion, removal of pedicle screws after one-segment fusion can increase spinal motion, reduce the stress on adjacent intervertebral discs and delay disc degeneration.

Outcome after thoracoscopic ventral stabilisation of thoracic and lumbar spine fractures

BACKGROUND AND PURPOSE

Thoracoscopic-assisted ventral stabilisation for thoracolumbar fractures has been shown to be associated with decreased recovery time and less morbidity when compared with open procedures. However, there are a limited number of studies evaluating late clinical and radiological results after thoracoscopic spinal surgery.

METHODS

We performed an analysis of the late outcomes of thoracolumbar fractures after minimally invasive thoracoscopic ventral instrumentation. Between August 2003 and December 2008, 70 patients with thoracolumbar fractures (T5-L2) underwent ventral thoracoscopic stabilisation. Tricortical bone grafts, anterior plating systems (MACS-System), and cage implants were used for stabilisation. Outcomes measured include radiologic images (superior inferior endplate angle), Visual Analogue Scale (VAS), VAS Spine Score, quality of life scores SF-36 and Oswestry Disability Index (ODI).

RESULTS

Forty seven patients (67%, 47 out of 70) were recruited for the follow up evaluation (2.2 ± 1.5 years). Lower VAS Spine scores were calculated in patients with intra- or postoperative complications (44.7 (± 16.7) vs. 65.8 (± 24.5), p=0.0447). There was no difference in outcome between patients treated with bone graft vs. cage implants. Loss of correction was observed in both bone graft and titanium cage groups.

INTERPRETATION

The present study demonstrates diminished long-term quality of life in patients treated with thoracoscopic ventral spine when compared with the outcome of german reference population. In contrast to the other patients, those patients without intra-operative or post-operative complications were associated with improved outcome. The stabilisation method (bone graft versus spinal cage) did not affect the long-term clinical or radiographic results in this series.

Anatomical parameters of subaxial percutaneous transfacet screw fixation based on the analysis of 50 computed tomography scans: Clinical article

OBJECT

Cervical transfacet screw placement has been described in the literature. Although the technique shows promise for percutaneous application, parameters for screw placement have not been well delineated. This study used reconstructed CT scans with imaging software to assess the feasibility of percutaneous transfacet screw placement, analyzing potential entry angles, transfacet lengths, and sex differences at each subaxial level.

METHODS

Fifty consecutive cervical CT scans (obtained in 26 males and 24 females [mean age 41.5 years]) were reformatted using OsiriX software, and transfacet lengths, entry angles, and potential occipital clearance were analyzed at all subaxial levels. Statistical analyses were used to determine the differences, if any, between transfacet lengths, entry angle, and occipital clearance across individual cervical levels. Repeatability was quantified by calculating the intraclass correlation coefficient and Cohen kappa value.

RESULTS

A total of 200 transfacet lengths and 200 entry angles in 50 patients were analyzed. The mean transfacet lengths were 17.9 ± 2.6, 17.6 ± 3.2, 16.3 ± 3.6, and 13.1 ± 2.2 mm at C3-4, C4-5, C5-6, and C6-7, respectively, with mean entry angles at 52.7° ± 7.8°, 56.5° ± 8.0°, 55.0° ± 8.8°, and 53.0° ± 8.7°, respectively. Analysis of variance revealed a significant difference between the mean transfacet lengths, while post hoc analysis revealed significantly larger transfacet lengths in the upper 2 cervical levels (C3-4 and C4-5) than in the lower 2 cervical levels (C5-6 and C6-7). Analysis of variance demonstrated no significant difference between the entry angles. Males had significantly larger transfacet lengths at C5-6 (17.4 vs 15.1 mm) and C6-7 (13.7 vs 12.4 mm) than females. The occiput would have blocked percutaneous screw placement in 86%, 78%, 54%, and 20% of the cases at C3-4, C4-5, C5-6, and C6-7, respectively. Transfacet lengths may accommodate longer screws in the upper cervical spine, but potential screw sizes decrease in the lower subaxial levels. A transfacet entry angle of approximately 50° or greater was associated with a higher incidence of occipital clearance. Additionally, the occiput may pose a significant obstruction to percutaneous transfacet fixation in upper subaxial levels. Interrater reliability was poor for screw angle and length measurements, but was satisfactory in intrarater analysis in 6 of 8 measurements. There was moderate to good agreement of occipital clearance in all but one measurement.

CONCLUSIONS

Cervical transfacet screw placement is possible from C-3 to C-7. Because occipital clearance can be difficult at C3-4 and C6-7, the use of curved or flexible instruments may be necessary to obtain the appropriate screw trajectory. Screw lengths varied with spinal level and the sex of the patient.

Minimally invasive thoracolumbar corpectomy and reconstruction

Minimally invasive surgical approaches have been advocated to approach ventrolateral thoracolumbar pathology. This article describes our technique for performing minimally invasive surgical thoracolumbar corpectomy and reconstruction. Twenty-five consecutive patients at a single institution were treated between 2006 and 2010 for a variety of diagnoses including tumors, infections, and trauma. Treatment variables, including operating time, estimated blood loss, number of levels treated, and complications, were collected, as were visual analog scale (VAS) scores for pain.Surgical times (mean, 188.5 minutes) and blood loss (mean, 423 mL) reflect a significant improvement over standard open corpectomy procedures. More than 60% of patients did not need blood products after the corpectomy procedure because substantial blood loss encountered during an open exposure to the spine was obviated. Similarly, operative times and anesthetic load was minimal enough for ≥80% of our patients to be extubated immediately after the corpectomy procedure. A 62% decrease in self-reported VAS scores was observed. No wound complications or radiographic evidence of implant subsidence or failure were observed at last follow-up.The advantages of the minimally invasive approach for corpectomies of the thoracolumbar spine were that an access surgeon was not needed; tissue dissection and surgical exposure were reduced, improving VAS scores postoperatively; and blood loss and operative times were minimized, preventing hemodynamic deterioration in these complex cases. Corpectomies may be performed in this fashion safely, with excellent pain relief and without many of the morbidities and difficulties associated with conventional open procedures.

Minimally invasive lateral approach for symptomatic thoracic disc herniation: initial multicenter clinical experience

OBJECT

Symptomatic herniated thoracic discs remain a surgical challenge and historically have been associated with significant complications. While neurological outcomes have improved with the abandonment of decompressive laminectomy, the attempt to minimize surgical complications and associated morbidities continues through less invasive approaches. Many of these techniques, such as thoracoscopy, have not been widely adopted due to technical difficulties. The current study was performed to examine the safety and early results of a minimally invasive lateral approach for symptomatic thoracic herniated intervertebral discs.

METHODS

Sixty patients from 5 institutions were treated using a mini-open lateral approach for 75 symptomatic thoracic herniated discs with or without calcification. The mean age was 57.9 years (range 23-80 years), and 53.3% of the patients were male. Treatment levels ranged from T4-5 to T11-12, with 1-3 levels being treated (mean 1.3 levels). The most common levels treated were T11-12 (14 cases [18.7%]), T7-8 (12 cases [16%]), and T8-9 (12 cases [16%]). Symptoms included myelopathy in 70% of cases, radiculopathy in 51.7%, axial back pain in 76.7%, and bladder and/or bowel dysfunction in 26.7%. Instrumentation included an interbody spacer in all but 6 cases (10%). Supplemental internal fixation included anterolateral plating in 33.3% of cases and pedicle screws in 10%; there was no supplemental internal fixation in 56.7% of cases. Follow-up ranged from 0.5 to 24 months (mean 11.0 months).

RESULTS

The median operating time, estimated blood loss, and length of stay were 182 minutes, 290 ml, and 5.0 days, respectively. Four major complications occurred (6.7%): pneumonia in 1 patient (1.7%); extrapleural free air in 1 patient (1.7%), treated with chest tube placement; new lower-extremity weakness in 1 patient (1.7%); and wound infection in posterior instrumentation in 1 patient (1.7%). Reoperations occurred in 3 cases (5%): one for posterior reexploration, one for infection in posterior instrumentation, and one for removal of symptomatic residual disc material. Back pain, measured using the visual analog scale, improved 60% from the preoperative score to the last follow-up, that is, from 7.8 to 3.1. Excellent or good overall outcomes were achieved in 80% of the patients, a fair or unchanged outcome resulted in 15%, and a poor outcome occurred in 5%. Moreover, myelopathy, radiculopathy, axial back pain, and bladder and/or bowel dysfunction improved in 83.3%, 87.0%, 91.1%, and 87.5% of cases, respectively.

CONCLUSIONS

The authors' early experience with a large multicenter series suggested that the minimally invasive lateral approach is a safe, reproducible, and efficacious procedure for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional surgical techniques and without the use of endoscopes. Symptom resolution was achieved at similar rates using this approach as compared with the most efficacious techniques in the literature, and with fewer complications in most circumstances.

Early surgery-related complications after anteroposterior stabilization of vertebral body fractures in the thoracolumbar region

BACKGROUND

The complication rate after trauma-associated spine surgery remains unknown because of the rarity of this injury and the polymorphism of treatment methods. We report the complication rates recorded at one center after treatment of unstable vertebral body fractures according to a single, uniform procedure. The aim of this analysis was to identify the typical complications associated with this surgical procedure and, consequently, to contribute to critical deliberations on the introduction of technical innovations such as navigation, intraoperative three-dimensional imaging, and neuromonitoring.

METHODS

Perioperative complications related to surgery of 208 consecutive patients, operated on for unstable vertebral body fractures were analyzed. First, stabilization was performed through an open, posterior, nonnavigated approach. This was followed, in all patients, by reconstruction of the anterior column form with a tricortical iliac crest graft during a second operation.

RESULTS

In regard to posterior stabilization, at least one pedicle screw in six patients (3%) was placed incorrectly; furthermore, there were five patients with general complications, all of which required revision surgery. After anterior spondylodesis, there were also nine general complications and five neurological complications, one of them in a patient with persistent paraplegia. At the graft donor site, three patients experienced an avulsion fracture of the anterosuperior iliac crest. Overall, at least one complication occurred in 13% of patients (confidence interval 0.08-0.18).

CONCLUSIONS

With regard to early complications, two-stage anteroposterior stabilization of unstable spinal fractures of the thoracolumbar spine is a reliable procedure.