Unstable Thoracolumbar Burst Fractures Research Articles

In Vitro Analysis of Anterior and Posterior Fixation in an Experimental Unstable Burst Fracture Model

A biomechanical comparison of fixation constructs in an experimental fracture model. To determine the relative postoperative stability of anterior graft and plating with that of posterior or combined fixation constructs in an unstable thoracolumbar burst fracture model. Several treatment modalities have been proposed for unstable thoracolumbar burst fractures, but the optimal technique is unclear. Previous cadaveric biomechanical studies in unstable burst fracture models have not considered the commonly used posterior (interpedicular) and anterior (plate) constructs. Nine human spine segments (T11-L3) were potted in epoxy and scanned using dual energy x-ray absorptiometry and computed tomography. Intact specimens had baseline flexibility testing. Unstable L1 burst fractures as verified by computed tomography were created using an impulse load and posterior surgical osteoligamentous destabilization (ie, transection of the lamina, interspinous ligaments, facet capsules, and ligamentum flavum). Specimens were instrumented posteriorly with pedicle screws and rods and tested to 6 Nm in flexion-extension, lateral bending, and torsion. Corpectomy and strut grafting were then performed, and testing was repeated in varying order with posterior fixation, anterior plating and circumferential fixation. Range of motion (ROM) and neutral zone was calculated for each test and fixation groups were compared using analysis of variance. All specimens had AO B1.2 (unstable burst) fractures. Mean ROM for posterior-only constructs was significantly less than that of the intact in lateral bending, flexion, and extension (P<0.001). Anterior-only constructs after corpectomy and strut grafting generally resulted in a smaller ROM versus intact in flexion (NS: P=0.1) and lateral bending (P<0.001). In contrast, all anterior-only and posterior constructs had greater ROM than intact in torsion (all at P<0.05). Circumferential fixation resulted in statistically smaller ROM compared with all other constructs (P< or =0.04), and reached that of the intact specimen in torsion. Increased ROM was correlated with greater fracture comminution for posterior-only fixation (P<0.05), and was weakly correlated with lower dual energy x-ray absorptiometry score (R=0.3) for anterior-only fixation. Circumferential instrumentation provided the most rigid fixation, followed by posterior fixation with anterior strut grafting, posterior fixation alone, and by anterior fixation with strut grafting. These results were dependent on bone quality and the comminution severity of the fracture. These results should aid surgical decision making in addition to other factors in the overall clinical situation.

Biomechanical comparison of three fixation techniques for unstable thoracolumbar burst fractures

Increased structural stability is considered sufficient justification for higher-risk surgical procedures, such as circumferential fixation after severe spinal destabilization. However, there is little biomechanical evidence to support such claims, particularly after traumatic lumbar burst fracture. The authors sought out to compare the biomechanical performance of the following 3 fixation strategies for spinal reconstruction after decompression for an unstable thoracolumbar burst fracture: 1) short-segment anterolateral fixation; 2) circumferential fixation; and 3) extended anterolateral fixation. Thoracolumbar spines (T10-L4) from 7 donors (mean age at death 64+/-6 years; 1 female and 6 males) were tested in pure moment loading in flexion-extension, lateral bending, and axial rotation. Thoracolumbar burst fractures were surgically induced at L-1, and testing was repeated sequentially for each of the following fixation techniques: short-segment anterolateral, circumferential, and extended anterolateral. Primary and coupled 3D motions were measured across the instrumented site (T12-L2) and compared across treatment groups. Circumferential and extended anterolateral fixations were statistically equivalent for primary and off-axis range-of-motions in all loading directions, and short-segment anterolateral fixation offered significantly less rigidity than the other 2 methods. The results of this study strongly suggest that extended anterolateral fixation is biomechanically comparable to circumferential fusion in the treatment of unstable thoracolumbar burst fractures with posterior column and posterior ligamentous injury. In cases in which an anterior procedure may be favored for load sharing or canal decompression, extension of the anterior instrumentation and fusion one level above and below the unstable segment can result in near equivalent stability to a 2-stage circumferential procedure.

The Surgical Management of Unstable Thoracolumbar Burst Fractures with Anterolateral and Posterior Approach: Comparison of Clinical and Radiological Outcome

Objective: The authors evaluate the clinical and radiographic outcome of the management of acute thoracolumbar burst fractures by anterolateral or posterior approach. Methods: Thirty four (34) consecutive patients with a single-level traumatic unstable burst fracture at the thoracolumbar junction were surgically treated between Jan. 2004 and Dec. 2006. Twenty one patients were operated on by anterolateral approach, strut graft and fixation with a Kaneda plate. Thirteen patients were treated with posterior approach and transpedicular screw fixation. Clinical and radiographic evaluation was performed on all 34 patients before and after surgery. Results: There were 34 thoracolumbar burst fractures in 27 male and 7 female patients. Fifty-nine percent (20 of 34) of patients presented with a neurologic deficit. The mean follow-up duration was 18.5 months (range 7-44 months). Preoperative canal encroachment in the anterolateral and posterior groups measured 49.3±7.6%, 27.3±9% respectively (p=0.001). Preoperative angular deformity in the anterolateral and posterior groups measured 19.4±8.4° and 12.9±4.5° respectively. At discharge, angular deformity had been corrected to 10.5± 7.3° and 7.6±4.9° in both groups, respectively. Preoperative Frankel grade grade in the anterolateral and posterior groups was 3.9±1.2, 3.9±1.5 respectively (p=0.9). Postoperatively, it had been improved to 4.4±1.1, 4.2±1.4 in both groups, respectively. Conclusion: Compared with posterior approaches, the anterolateral approach can reduce fusion segment, well maintained the kyphosis correction and decompress the spinal canal completely. The selection of treatment should be based on clinical and radiological finding including neurological deficit. (J Kor Neurotraumatol Soc 2008;4:37-42)

Thoracolumbar Spine Trauma

Thoracic and lumbar fractures are highly prevalent injuries. No accepted operative treatment protocol exists for the management of burst fractures in this region, and anterior, posterior, and combined approaches all have been successfully described in the literature. Appropriate surgical strategy is dependent on an accurate assessment of spinal stability, the neurologic status of the patient, and the morphology of injury. Posterior instrumentation using distraction and ligamentotaxis is a well-accepted method for addressing unstable thoracolumbar burst fractures with or without an associated neurologic deficit in which direct decompression is not required. Anterior decompression, however, remains the preferred method of treatment for burst fractures with incomplete neurologic deficits in association with significant canal occlusion and relative sparing of the posterior ligamentous complex. In this work, we explore the indications, contraindications, and technical complexities of posterior decompression with pedicle screw instrumentation, distraction, and ligamentotaxis, as well as anterior decompression and interbody fusion.

The Effect of Pedicle Screw Instrumentation on Fractured Vertebrae in Unstable Thoracolumbar Burst Fractures with Canal Encroachment and Clinical Result

Study Design: A retrospective study. Objectives: To evaluate the canal encroachment of fractured bony fragments and neurological deficits of pedicle screw instrumentation for the treatment of unstable thoracolumbar burst fractures with pedicle screws inserted into the fractured vertebrae. Materials and Methods: The authors evaluated 18 patients treated surgically with posterior fusions using pedicle screws for unstable thoracolumbar burst fractures, from March 2000 to September 2004. The ratios of the areas occupied by the fractured bony fragments in the canals were analyzed, before and after pedicle screw insertion, by computed tomography scans of the fractured vertebrae. The kyphotic angles, anterior vertebral heights, and neurological deficits were evaluated. Results: The areas occupied by the fractured fragments in the canals were improved significantly after surgery and there were no neurological complications resulting from the placement of pedicle screws or fragment displacements. The kyphotic angles and anterior vertebral heights at the last follow-up visits were improved significantly compared with the preoperative radiographs. The neurological deficits were not aggravated after pedicle screw insertion. Conclusion: Our results suggest that pedicle screw instrumentation in fractured vertebrae is safe and effective for the treatment of unstable thoracolumbar burst fractures.

Relationships Between Canal Occlusion and Neurologic Deficits, and Between Kyphotic Deformities and Fracture Types in Unstable Thoracolumbar Burst Fractures

Study Design: A retrospective study. O b j e c t i v e s: To evaluate the relationships between spinal canal occlusion and neurologic deficits, and between spinal canal decompression and neurologic recovery in thoracolumbar burst fractures. Kyphotic deformities, based on the fracture types in short-segment instrumentation and fusion, were evaluated to determine effective operative methods. Summary of Literature Review: In thoracolumbar burst fractures, the relationship between spinal canal occlusion and neurologic deficits remains controversial; and definitive guidelines for short-segment instrumentation and fusion have not been established . Materials and Methods: Surgically treated thoracolumbar burst fractures (N=112) were analyzed retrospectively. Spinal canal occlusion in both neurologically intact and deficient groups, and neurologic recovery as a result of spinal canal decompression, were evaluated based on Frankel’s grades. Kyphotic deformities based on the Denis classification and McCormack’s load sharing classification were evaluated in 86 short-segment instrumentation patients. Results: Spinal canal occlusion in the neurologically deficient group (51.8%) was significantly higher than that in the neurologically intact group (31.4%) (p 0.05). Kyphotic deformities were increased significantly in Denis type A, B and groups with more than 7 points in the load sharing classification (p<0.05). Conclusion: In thoracolumbar burst fractures, the degree of initial spinal canal occlusion was more significantly related with neurologic deficits than with postoperative spinal canal decompression. Extended instrumentation and fusion is recommended for reducing postoperative kyphotic deformities in Denis type A, B and groups with more than 7 points in the load sharing classification.

Unstable burst fractures of the thoraco-lumbar junction: treatment by posterior bisegmental correction/fixation and staged anterior corpectomy and titanium cage implantation

Controversy exists about the best treatment of unstable thoraco-lumbar (TL) burst fractures. Kyphosis correction and canal decompression in case of a neurological deficit are recognized treatment objectives, and various conservative and surgical strategies have been proposed. This prospective observational study evaluates the benefits and risks of a posterior bisegmental transpedicular correction/fixation and staged anterior corpectomy and titanium cage implantation in unstable TL junction burst fractures. 20 consecutive patients with a single-level traumatic unstable burst fracture at the TL junction were operated on by a bisegmental posterior correction/fixation, followed by anterior corpectomy and titanium cage implantation 7-10 days later. The radiological and clinical course is documented over a period of 24 months. The mean posttraumatic loss of anterior vertebral body height was 58% (45-70%). The posttraumatic mean regional kyphosis was 16 degrees and could be corrected by the posterior approach to a mean lordosis of 2 degrees. Mean secondary loss of the kyphosis correction was 3 degrees over 24 months. No hardware failure occurred, and construct stability was observed in all 20 patients. One surgical complication occurred during the posterior approach, and three transient surgical complications by the anterior approach. 12 of the 14 patients with an initial neurological deficit recovered an average of 1.5 grades on the ASIA scale. At 24 months postoperatively, the mean regional TL back pain on a VAS (0-10) was 1.6, and the mean pain at the anterior approach site was 1.2. Posterior bisegmental transpedicular correction/fixation and staged anterior corpectomy and titanium cage implantation is a safe and reliable surgical treatment option in unstable TL junction burst fractures. The advantages of this technique are a complete kyphosis correction, immediate stability, maintenance of kyphosis correction, and complete spinal canal decompression in case of a neurological deficit. However, these advantages have to be carefully weighed against the double approach morbidity.

72. Less invasive treatment of unstable thoracolumbar burst fractures with short segment fixation balloon assisted reduction and anterior column reconstruction with calcium phosphate cement

72. Less invasive treatment of unstable thoracolumbar burst fractures with short segment fixation balloon assisted reduction and anterior column reconstruction with calcium phosphate cement

A new technique for the surgical management of unstable thoracolumbar burst fractures: a modification of the anterior approach and an outcome comparison to traditional methods

This study was conducted to determine the safety, efficacy, and complication rate associated with the anterior approach in the use of a new titanium mesh interbody fusion cage for the treatment of unstable thoracolumbar burst fractures. The experience with this technique is compared with the senior authors' (C.S., R.W., and M.S.) previously published results in the management of patients with unstable thoracolumbar burst fractures. Between 1996 and 1999, 21 patients with unstable thoracolumbar (T12-L3) burst fractures underwent an anterolateral decompressive procedure in which a titanium cage and Kaneda device were used. Eleven of the 21 patients had sustained a neurological deficit, and all patients improved at least one Frankel grade (average 1.2 grades). There was improvement in outcome in terms of blood loss, correction of kyphosis, and pain, as measured on the Denis Pain and Work Scale, in our current group of patients treated via an anterior approach when compared with the results in those who underwent a posterior approach. In our current study the anterior approach was demonstrated to be a safe and effective technique for the management of unstable thoracolumbar burst fractures. It offers superior results compared with the posterior approach. The addition of the new titanium mesh interbody cage to our previous anterior technique allows the patient's own bone to be harvested from the corpectomy site and used as a substrate for fusion, thereby obviating the need for iliac crest harvest. The use of the cage in association with the Kaneda device allows for improved correction of kyphosis and restoration of normal sagittal alignment in addition to improved functional outcomes.

The efficiency of ultrasound guided spinal fracture reposition

To calculate canal compromise and decrease of midsagittal diameter caused by retropulsion of fragments into the spinal canal we analyzed the pre- and postoperative computed tomographies of 32 patients with unstable thoracolumbar burst fractures treated by USS (universal spine system). Our intention was to examine the efficiency of ultrasound guided repositioning of the dispaced fragments which was performed in all 32 cases. We found a clear postoperative enlargement of canal area (ASP preoperatively 55 %, postop. 80 %) and midsagittal diameter (MSD preop. 58 %, postop. 78 %). 10 of 13 patients presented a postoperative improvement of neurological deficit, no neurological deterioration occured. Fractures with neurological deficit showed more canal compromise (52 %) and less midsagittal diameter (MSD compromise 51 %) than those without (40 % or 39 %). There was no correlation between the percentage of spinal canal stenosis and the severity of neurological deficit. Below L 1 the spinal canal is greater than between Th 11 and L 1, so a more important spinal stenosis is tolerated. In case of unstable burst fractures with neurological deficit the ultrasound guided spinal fracture reposition is an effective procedure concerning the necessary improvement of spinal stenosis: an additional ventral approach for the revision of the spinal canal is unneeded. In fractures without neurologic deficit the repositioning of the displaced fragments promises an avoidance of long-term damages such as myelopathia and claudicatio spinalis.

Efficacy of ultrasound controlled direct reposition of fragments of the posterior vertebral body facet

To calculate canal compromise and decrease of midsagittal diameter caused by retropulsion of fragments into the spinal canal we analyzed the pre- and postoperative computed tomographies of 32 patients with unstable thoracolumbar burst fractures treated by USS (universal spine system). Our intention was to examine the efficiency of ultrasound guided repositioning of the dispaced fragments which was performed in all 32 cases. We found a clear postoperative enlargement of canal area (ASP preoperatively 55%, postop. 80%) and midsagittal diameter (MSD preop. 58%, postop. 78%). 10 of 13 patients presented a postoperative improvement of neurological deficit, no neurological deterioration occurred. Fractures with neurological deficit showed more canal compromise (52%) and less midsagittal diameter (MSD compromise 51%) than those without (40% or 39%). There was no correlation between the percentage of spinal canal stenosis and the severity of neurological deficit. Below L 1 the spinal canal is greater than between Th 11 and L 1, so a more important spinal stenosis is tolerated. In case of unstable burst fractures with neurological deficit the ultrasound guided spinal fracture reposition is an effective procedure concerning the necessary improvement of spinal stenosis: an additional ventral approach for the revision of the spinal canal is unneeded. In fractures without neurologic deficit the repositioning of the displaced fragments promises an avoidance of long-term damages such as myelopathia and claudicatio spinalis.

Functional outcome of thoracolumbar burst fractures managed with hyperextension casting or bracing and early mobilization.

A retrospective study to review the results of unstable thoracolumbar burst fractures managed with casting or bracing and early ambulation in neurologically healthy patients. To determine the clinical outcome of patients with unstable burst fractures of the thoracolumbar spine treated without surgery, and to identify any variables that may adversely influence the final outcome. The management of unstable fractures of the thoracolumbar spine as described by Bedbrook involves a period of recumbency for 6-8 weeks followed by gradual mobilization. Newer techniques of surgical stabilization of the fracture and decompression of the neural elements have become popular because immediate stability of the spine is created and because the need for prolonged bedrest and hospitalization is eliminated. There have been only three reports in the literature describing the nonoperative management of these fractures with early mobilization; some authors believe that this is appropriate only if the posterior column is intact. The results reported in the literature of nonoperative management of thoracolumbar burst fractures have indicated that this is an effective method of management. A retrospective review of 26 patients with unstable burst fractures in the thoracolumbar region (T11-L2) was performed; follow-up evaluation was obtained from 24 patients. Clinical follow-up examination was performed by the use of a questionnaire in which the patients were asked to rate their pain, ability to work, ability to perform in recreational activities, and their overall satisfaction with treatment. Mean follow-up time for the 24 patients was 34.3 months. Mean duration of hospitalization was 8.2 days; those patients who did not have injuries other than their spine fracture had a mean hospitalization time of 5.9 days. Kyphotic deformity could be corrected with hyperextension casting but tended to recur during the course of mobilization and healing. No correlation was found between kyphosis and clinical outcome. At final follow-up evaluation, 19 patients (79%) had little or no pain; 18 patients (75%) had returned to work; 18 (75%) stated that they had little or no restrictions in their ability to work, and 16 (67%) stated that they had little or no restrictions in their ability to participate in recreational activities. Only one patient (4%) reported being dissatisfied with the initial nonoperative treatment of his spine fracture. Ten patients were found to have evidence of spinous process widening on plain films; there was no significant difference in the clinical or radiographic outcome of these 10 patients when compared with the 14 others who did not have interspinous widening. Nonoperative management of thoracolumbar burst fractures with hyperextension casting or bracing was proven to be a safe and effective method of treatment in selected patients. Clinical results were favorable; no neurologic deterioration was observed; hospitalization times were minimized, and patient satisfaction was high. The authors do not believe that ligamentous injury of the posterior column is a contraindication to nonoperative management of thoracolumbar burst fractures.

Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes.

The authors retrospectively studied 49 nonparaplegic patients who sustained acute unstable thoracolumbar burst fractures. All patients underwent surgical treatment and were followed for an average of 27 months. All but one patient achieved solid radiographic fusion. Three treatment groups were studied: the first group of 16 patients underwent anterior decompression and fusion with instrumentation; the second group of 27 patients underwent posterior decompression and fusion; and the third group of six patients had combined anterior-posterior surgery. Prior to surgical intervention, these groups were compared and found to be similar in age, gender, level of injury, percentage of canal compromise, neurological function, and kyphosis. Patients treated with posterior surgery had a statistically significant diminution in operative time and blood loss and number of units transfused. There were no significant intergroup differences when considering postoperative kyphotic correction, neurological function, pain assessment, or the ability to return to work. Posterior surgery was found to be as effective as anterior or anterior-posterior surgery when treating unstable thoracolumbar burst fractures. Posterior surgery, however, takes the least time, causes the least blood loss, and is the least expensive of the three procedures.

Unstable Thoracolumbar and Lumbar Burst Fractures Treated with the AO Fixateur Interne

Twenty-five consecutive patients with unstable thoracolumbar and lumbar burst fractures were surgically treated with the AO Fixateur Interne (Synthes USA, 1690 Russell Rd., Paoli, PA). Indications for surgery included a progressive neurologic deficit, spinal canal compromise greater than 50%, vertebral body collapse greater than 50%, or sagittal angulation greater than 20 degrees. Twenty males and five females ranging in age from 16 to 60 years (average 31) were treated surgically and prospectively followed. Twenty-one fractures occurred at the thoracolumbar junction (T10-L2) and 4 in the lumbar spine (L3-5). Twenty-four patients were followed for a minimum of 12 months, ranging from 12 to 38 months (average 22); one patient was lost to follow-up after 1 month postoperatively. Preoperatively, 12 patients had partial neurologic deficits; postoperatively, 11 improved at least 1 Frankel grade. Preoperatively, the 12 patients with partial neurologic deficits averaged 45 points (range 24-49) on the lower extremity motor index scale. After surgery, these patients improved an average of five points (range 1-23) on the motor index scale. Both patients with complete spinal cord injuries remained unchanged neurologically postoperatively; no patients deteriorated neurologically after surgery. The average preoperative sagittal kyphosis at the fracture site was +16 degrees (range +10 degrees to +31 degrees); the immediate postoperative sagittal angular correction averaged -4 degrees (lordosis) and ranged from +12 degrees (kyphosis) to -26 degrees (lordosis). At last follow-up, the sagittal angular correction remained unchanged in three patients and decreased in 21 patients to an average of +5 degrees (range +37 degrees to -14 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

A reduction-fixation system for unstable thoracolumbar burst fractures.

Thirty-three patients with unstable burst fractures of the lower thoracic and lumbar spine were treated with a reduction-fixation system. The new system is used both as a reduction and a fixation device for disorders of the lower thoracic and lumbar spine. In treatment of spinal fractures, it provides symmetric lordotic distraction to obtain the best possible reduction of intracanal fragments, and rigidly stabilizes the fractured vertebra while involving the minimum number of segments. All patients had a minimum follow-up of 24 months. Most patients in this series had a near-anatomic reduction of all three columns in the involved segment. The "indirect" neurologic decompression was successful in cases treated early after injury. The fixation was rigid enough to allow early mobilization and rehabilitation in a light orthosis within 1 week after surgery, and there was minimal loss of reduction during the follow-up period. The complications were minor. The reduction-fixation system achieved the surgical goals of posterior instrumentation for treatment of unstable thoracolumbar burst fractures.