Indirect spinal canal decompression of vertebral burst fracture in calf model

Introduction An experimental study of experimental burst fractures in bovine spinal specimens was conducted to analyze the effects of transpedicular short-segment posterior fixation followed by reduction on indirect spinal canal decompression.Materials and methods For this purpose, experimental burst fractures were created in 11 bovine specimens with a hydraulic materials-testing machine. The specimens were evaluated with plain radiographs and CT scans before reduction. Thereafter, they were instrumented with titanium transpedicular screws and rods (short-segment posterior fixation); and reduction was achieved which included distraction and kyphosis correction maneuvers.Results Each spinal specimen was evaluated with plain radiographs and CT scans after reduction by applying distraction and kyphosis correction maneuvers. Plain radiographic analysis showed that the kyphosis angle and segmental height values improved. Furthermore, CT scans revealed that the spinal canal diameter values improved compared with those before reduction. The differences between before and after reduction in kyphosis angle, segmental height, anterior body compression, and percentage of retropulsion were statistically significant.Conclusion Short-segment posterior fixation followed by indirect spinal canal decompression led to an improvement over spinal canal retropulsion in experimental burst fractures. Furthermore, the kyphosis angle and segmental height values improved following the reduction compared with those before reduction.The present study was performed in the Department of Orthopaedics and Traumatology, Cumhuriyet University School of Medicine, and Cumhuriyet University Technical School Laboratory.     

Vertebral burst fractures: an experimental, morphologic, and radiographic study.

Spinal burst fractures are produced by rapid compressive loading, and may result in spinal cord injury from bone fragments forced from the vertebral body into the spinal canal. This fracture is one of the most difficult injuries of the spine to successfully treat, in part because the biomechanics of reduction and the exact mechanism by which the distraction forces are transmitted to the intracanal fragments of the burst fracture have not been adequately investigated. The authors developed a reproducible technique for creating these fractures in vitro. The fractures produced were identical to those observed in clinical practice, and were used for investigating the mechanics of this fracture and its reduction. This work describes the pathologic anatomy of the burst fracture both on the gross structure and also on microtome sections of the vertebrae, and examines the biomechanics of fracture reduction. The margins of the vertebral bone fragment, which was forced posteriorly into the spinal canal during fracture, were noted to extend far laterally beyond the pedicles. The authors also found extensive damage not only to the disc above the injured level, but also to that below, explaining the clinical observation that disc degeneration frequently occurs at both levels. Examination of anatomic data provided by microtome section supported the hypothesis that the fibers that actually reduce the intracanal fragment originate in the anulus of the superior vertebra in the midportion of the endplate and insert into the lateral margins of the intracanal fragment. Investigations using magnetic resonance imaging confirmed that these obliquely directed fibers account for the indirect reduction of the fragment. The authors' studies demonstrate that the posterior longitudinal ligament provides only a minor contribution in the reduction of the fracture in comparison to the attachments of the posterior portion of the anulus fibrosus. The forces required to reduce this fragment were studied. Distraction was found to be the predominant force required for indirect posterior reduction. This was confirmed by a series of tests using devices that provided segmental fixation. The application of uniform distraction forces was most effective in the posterior reduction of the intracanal fragment.     

Percutaneous vertebroplasty for the treatment of osteoporotic burst fractures

Background  Vertebroplasty is a minimally invasive surgical procedure which involves injecting polymethylmethacrylate into the compressed vertebral body. At present the indications include the treatment of osteoporotic compression fractures, vertebral myeloma, and metastases. The value of vertebroplasty in osteoporotic compression fracture has been discussed comprehensively. The surgical operation for burst fractures without neurological deficit remains controversial. Some authors have asserted that vertebroplasty is contraindicated in patients with burst fracture. However, we performed the procedure, after considering the patents general condition, to reduce surgical risks and the duration of immobilisation. The purpose of this study is to investigate clinical outcomes, kyphosis correction, wedge angle, and height restoration of thoraco-lumbar osteoporotic burst fractures treated by percutaneous vertebroplasty. Materials and methods  Twenty-five patients with osteoporotic burst fracture were treated with postural reduction followed by vertebroplasty. We measured the kyphosis, wedge angle, spinal canal compromise and the height of the fractured vertebral body initially, after postural reduction, and after vertebroplasty. Findings  The average height of the collapsed vertebral bodies was 24.8% of the original height. Average kyphosis angle was 19.4° and average wedge angle was 19.8° at first. Mean canal encroachment was initially 25.1%. Kyphosis angle, wedge angle, and anterior, middle, and posterior height improved significantly after the procedure. The mean amelioration of the spinal canal encroachment after vertebroplasty was 23.3%. The average increase in anterior vertebral body height was 7.5 mm, central was 5.8 mm, and posterior was 0.9 mm. The mean reduction in kyphosis angle was 6.8° and the mean reduction in wedge angle was 9.7°. Conclusion  Although vertebroplasty has been considered as contraindicated in thoraco-lumbar burst fractures, we successfully used the procedure as a safe treatment in patients with osteoporotic burst fracture without neurologic deficit. This method could eliminate the need for and risks of major spinal surgery. We would like to offer it as a relatively safe and effective methods of management in thoraco-lumbar burst fractures.     

The phenomenon and efficiency of ligamentotaxis after dorsal stabilization of thoracolumbar burst fractures

Thirty-six consecutive patients with burst fractures of the thoracolumbar spine and with a fractured posterior vertebral surface dislocated into the spinal canal without neurological symptoms were treated with the AO internal fixator. Computed tomography-aided planimetry of the spinal canal was undertaken preoperatively and within 1 week postoperatively to elucidate the effect of kyphosis correction and distraction on spinal canal widening (ligamentotaxis). The stenosis of the spinal canal area (SCA) was reduced from 29% preoperatively to 19% postoperatively (+10%) of the estimated original area, and the stenosis of the mid-sagittal diameter (MSD) reduced from 31 to 23% (+8%). The widening of the SCA was greater at the level of L1/L2 (+13%) than at L3/L4 (+6%). High preoperative canal compromise was associated with greater absolute spinal canal widening. Large trapezoid-shaped fragments resisted reduction by ligamentotaxis. Even though the effect of ligamentotaxis after operative treatment with the internal fixator was proven, a certain stenosis of the spinal canal remains in most cases. Especially for patients with fracture-related neurological symptoms, ligamentotaxis alone does not seem sufficient for the requested spinal decompression. Even an exact analysis of preoperative CT scans under consideration of the fracture level will not always allow an exact prognosis of the expected effect of ligamentotaxis.     

Modified transpedicular approach for the surgical treatment of severe thoracolumbar or lumbar burst fractures.

BACKGROUND CONTEXT: Conventional transpedicular decompression of the neural canal requires a considerable amount of lamina, facet joint and pedicle resection. The authors assumed that it would be possible to remove the retropulsed bone fragment by carving the pedicle with a high-speed drill without destroying the vertebral elements contributing to spinal stabilization. In this way, surgical treatment of unstable burst fractures can be performed less invasively. PURPOSE: The purpose of this study is to demonstrate both the possibility of neural canal decompression through a transpedicular approach without removing the posterior vertebral elements, which contribute to spinal stabilization, and the adequacy of posterior stabilization of severe vertebral deformities after burst fractures. STUDY DESIGN: Twenty-eight consecutive patients with complete or incomplete neurological deficits as a result of the thoracolumbar burst fractures were included in this study. All patients had severe spinal canal compromise (mean, 59.53%+/-14.92) and loss of vertebral body height (mean, 45.14%+/-7.19). Each patient was investigated for neural canal compromise, degree of kyphosis at fracture level and fusion after operation by computed tomography and direct roentgenograms taken preoperatively, early postoperatively and late postoperatively. The neurological condition of the patients was recorded in the early and late postoperative period according to Benzel-Larson grading systems. The outcome of the study was evaluated with regard to the adequate neural canal decompression, fusion and reoperation percents and neurological improvement. METHODS: Modified transpedicular approach includes drilling the pedicle for removal of retropulsed bone fragment under surgical microscope without damaging the anatomic continuity of posterior column. Stabilization with pedicle screw fixation and posterior fusion with otogenous bone chips were done after this decompression procedure at all 28 patients included in this study. RESULTS: Twenty-three of 28 patients showed neurological improvement. The percent of ambulatory patients was 71.4% 6 months after the operation. The major complications included pseudarthrosis in five patients (17.8%), epidural hematoma in one (3.5%) and inadequate decompression in one (3.5%). These patients were reoperated on by means of an anterior approach. Of the five pseudarthrosis cases, two were the result of infection. CONCLUSION: Although anterior vertebrectomy and fusion is generally recommended for burst fractures causing canal compromise, in these patients adequate neural canal decompression can also be achieved by a modified transpedicular approach less invasively.     

Anatomical restoration of thoracolumbar spine with burst fracture]

A burst fracture was created in the L1 vertebra of six fresh human cadaver spines and reduction was performed using AO fixator intern, reduction fixation (RF) device, and Steffee plate instrumentation systems to determine the reduction force (distraction vs distraction plus lordosis) contributing to the anatomical restoration of thoracolumbar spine. These three pedicular screw devices were applied to the specimens following the use of standard clinical technique for each device. The AO fixator intern and the RF device provided independent control of distraction and lordosis correction. The Steffee device maintained a set distraction and lordosis. The RF device provided pre-set fixed incremental lordosis, while the AO provided variable angular correction. Plain X-rays and CT scans were taken of the specimens before and after creation of the fracture and following application of each device. Results demonstrated that the symmetric lordotic distraction of the disc space and vertebral body provided by the RF device achieved the best possible reduction of the intracanal fragment and sagittal alignment.     

Neurologic recovery from thoracolumbar burst fractures: is it predicted by the amount of initial canal encroachment and kyphotic deformity?

BACKGROUND: The association between neurologic recovery and initial compromise of spinal canal and sagittal alignment has been rarely documented. This study was performed to better understand whether the degree of neurologic recovery from thoracolumbar burst fractures is affected and predicted by initial compromise of spinal canal and sagittal alignment. METHODS: Eighty-seven patients who underwent conservative or surgical treatment for thoracolumbar burst fractures between 1993 and 2001 were prospectively followed up for 3 to 10 years (average, 5.5 years). They were assessed for neurologic deficit and improvement as defined by the scoring system of ASIA, the stenotic ratio of spinal canal and kyphosis angle. RESULTS: The ASIA score in 52 patients with neurologic deficit averaged 34.0 (range, 0-50) on admission and 46.1 (range, 27-50) at final follow-up. All these patients except 2 with neurologic deficit experienced improvement with an average recovery rate of 72.7% (range, 0%-100%). No statistically significant difference (P > .05) in the stenotic ratio of spinal canal or kyphotic deformity was demonstrated among the patients with no neurologic deficit, with incomplete lesions, and with complete lesions. The stenotic ratio of spinal canal or kyphosis angle was not significantly correlated with initial and final ASIA score and recovery rate (P > .05). CONCLUSIONS: The neurologic recovery from thoracolumbar burst fractures is not predicted by the amount of initial canal encroachment and kyphotic deformity. When deciding on the treatment for patients with thoracolumbar burst fractures, both neurologic function and spinal stability should be taken into account.     

Neurologic injury and recovery patterns in burst fractures at the T12 or L1 motion segment

Fourteen consecutive patients with burst fractures at T12 or L1, partial paralysis, and more than 30% canal compromise were prospectively evaluated pretreatment and posttreatment with roentgenograms to determine the initial fracture pattern, CT scans to determine the percent canal compromise and subsequent improvement, and a quantitative motor trauma index scale and bladder sphincter evaluation to determine neurologic recovery. The follow-up period averaged 32 months (range, 12-50 months). Treatment was as follows: nonoperative (three patients), Harrington rods and fusion (seven patients), and Harrington rods and fusion followed by anterior decompression and fusion (four patients). The initial severity of paralysis did not correlate with the initial fracture roentgenographic pattern or the amount of initial CT canal compromise. Neurologic recovery did not correlate with the treatment method or amount of canal decompression. Subsequent recovery did correlate with the initial fracture pattern. If the patient had a Type I or Type II fracture (both greater than 15 degrees kyphosis), greater than 90% neurologic recovery occurred, regardless of treatment. If the patient had a Type III fracture (less than 15 degrees kyphosis and the maximal canal compromise where bone encircles the canal) less than 50% neurologic recovery occurred. If the patient had a Type IV fracture (less than or equal to 15 degrees kyphosis and the maximal canal compromise at the level of the ligamentum flavum), the neurologic recovery was variable. Prognosis for neurologic recovery can be made based on initial roentgenograms. If greater than 15 degrees kyphosis is present, there is a good prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical outcomes of temporary short-segment instrumentation without augmentation for thoracolumbar burst fractures

BackgroundShort-segment posterior spinal instrumentation for thoracolumbar burst fracture provides superior correction of kyphosis by an indirect reduction technique, but it has a high failure rate. We investigated the clinical and radiological results of temporary short-segment pedicle screw fixation without augmentation performed for thoracolumbar burst fractures with the goal of avoiding treatment failure by waiting to see if anterior reconstruction was necessary.MethodsWe studied 27 consecutive patients with thoracolumbar burst fracture who underwent short-segment posterior instrumentation using ligamentotaxis with Schanz screws and without augmentation. Implants were removed approximately 1 year after surgery. Neurological function, kyphotic deformity, canal compromise, fracture severity, and back pain were evaluated prospectively.ResultsAfter surgery, all patients with neurological deficit had improvement equivalent to at least 1 grade on the American Spinal Injury Association impairment scale and had fracture union. Kyphotic deformity was reduced significantly, and maintenance of the reduced vertebra was successful even without vertebroplasty, regardless of load-sharing classification. Therefore, no patients required additional anterior reconstruction. Postoperative correction loss occurred because of disc degeneration, especially after implant removal. Ten patients had increasing back pain, and there are some correlations between the progression of kyphosis and back pain aggravation.ConclusionTemporary short-segment fixation without augmentation yielded satisfactory results in reduction and maintenance of fractured vertebrae, and maintenance was independent of load-sharing classification. Kyphotic change was caused by loss of disc height mostly after implant removal. Such change might have been inevitable because adjacent endplates can be injured during the original spinal trauma. Kyphotic change after implant removal may thus be a limitation of this surgical procedure.     

Thoracolumbar fracture management: anterior approach

The surgeon who treats patients with spine trauma must be able to apply a variety of management techniques to achieve optimal care of the patient. The anterior surgical approach is appropriate for some thoracolumbar burst fractures in patients with neurologic deficit and without posterior ligamentous injury. Surgery is most often indicated for patients with incomplete deficit, especially those with a large retropulsed fragment, marked canal compromise, severe anterior comminution, or kyphosis <30 degrees. This approach provides excellent visualization of the anterior aspect of the dura mater for decompression. Reconstruction of the anterior body defect can be done with autograft, allograft, or a cage. Supplementation of the graft with anterior internal fixation helps prevent kyphosis. Clinical results demonstrate improved neurologic function in most patients as well as low pseudarthrosis rates. In patients with incomplete deficit, improvement in neurologic function usually can be expected with few complications.     

Intraoperative ultrasonography for reduction of thoracolumbar burst fractures

The purpose of this study was to determine the efficacy of intraoperative ultrasound monitoring in the reduction and stabilization of thoracolumbar burst fractures of the spine. Thirty-one patients underwent a posterior approach for reduction and stabilization of a thoracolumbar burst fracture, with complete follow-up available on 26. Intraoperative real-time sonography was used for monitoring retropulsed fragments during distraction and fracture impaction. Computed tomography was used to compare preoperative canal compromise and postoperative reduction. Average canal compromise preoperatively was 66.5%, and the average canal compromise postoperatively was 18.7%. Neurologic function was not changed in 16, improved in ten, and worsened in none. Average hospital stay was 21.6 days. No complications were directly attributable to the use of the ultrasound. The authors believe that ultrasonography provides a safe and accurate method of intraoperatively evaluating reduction of burst fracture of the thoracolumbar spine from the posterior approach.     

Posterior instrumentation for thoracolumbar fractures

Thoracolumbar fractures are relatively common injuries. Numerous classification systems have been developed to characterize these fractures and their prognostic and therapeutic implications. Recent emphasis on short, rigid fixation has influenced surgical management. Most compression and stable burst fractures should be treated nonsurgically. Neurologically intact patients with unstable burst fractures that have >25 degrees of kyphosis, >50% loss of vertebral height, or >40% canal compromise often can be treated with short, rigid posterior fusions. Patients with unstable burst fractures and neurologic deficits require direct or indirect decompression. Posterior stabilization can be effective with Chance fractures and flexion-distraction injuries that have marked kyphosis, and in translational or shear injuries. Advances in understanding both biomechanics and types of fixation have influenced the development of reliable systems that can effectively stabilize these fractures and permit early mobilization.     

Comparison of two Types of Surgery for Thoraco-Lumbar Burst Fractures: Combined Anterior and Posterior Stabilisation vs. Posterior Instrumentation Only

Summary  This retrospective study compares clinical outcome following two different types of surgery for thoracolumbar burst fractures. Forty-six patients with thoracolumbar burst fractures causing encroachment of the spinal canal greater than 50% were operated on within 30 days performing either: combined anterior decompression and stabilisation and posterior stabilisation (Group 1) or posterior distraction and stabilisation using pedicle instrumentation (AO internal fixator) (Group 2). We evaluated: neurological status (Frankel Grade), spinal deformities, residual pain, and complications. The average follow-up was 6 years. There were no significant differences between the patients in both groups concerning age, sex, cause of injury and the presence of other severe injuries. Neurological dysfunction was present in 39% of all cases. Bony union occurred in all patients. Loss of reduction greater than 5 degrees and instrumentation failure occurred significantly more often in Group 2 compared to Group 1, but the kyphosis angle at late follow-up did not differ between groups, due to some degree of overcorrection initially after surgery in Group 2. The clinical outcome was similar in both groups, and all but one patient with neurological deficits improved by at least one Frankel grade.  Indirect decompression of the spinal canal by posterior distraction and short-segment stabilisation with AO internal fixator is considered appropriate treatment for the majority of unstable thoracolumbar burst fractures. This is a less extensive surgical procedure than a combined anterior and posterior approach.     

Evaluation of surgical treatment for burst fractures

The authors instituted a prospective, randomized study of patients presenting with acute burst fractures of the thoracolumbar and lumbar spine. Patients were alternately treated by posterior distraction using pedicle instrumentation (AO fixateur interne) or anterior decompression and instrumentation (Kostuik-Harrington device). Forty patients are presented with a mean follow-up of 20 months. Preoperatively, there was significant canal compromise in 39 patients. This measured 44.5% in those patients undergoing posterior surgery and 58% in those patients undergoing anterior surgery. Postoperatively, this was reduced to 16.5% and 4%, respectively. There is a statistically significant difference between these two groups (P less than 0.0001). The mean preoperative kyphotic deformity was 18.7 degrees in those patients treated by anterior surgery and 18.2 degrees in the group treated by posterior surgery. At last follow-up, the mean improvement in kyphotic deformity was 9.3 degrees in the anterior group and 11.3 degrees in the posterior group. There is no statistically significant difference between these two groups. There were two implant failures of the anterior Kostuik-Harrington construct and two implant failures of the AO fixateur interne. Blood loss was significantly higher in the patients undergoing anterior surgery, but there were no complications from thoracotomy and anterior decompression of the dural sac. This study supports the hypothesis that posterior distraction instrumentation can effectively decompress the canal and correct kyphosis in patients sustaining burst-type injuries. Anterior surgery, however, results in a more complete and reliable decompression of the canal.     

Surgical outcome of thoracolumbar burst fractures with flexion–distraction injury of the posterior elements

Between 1991 and 2002 we treated 48 patients surgically for thoracolumbar burst fractures associated with flexion–distraction injury of the posterior elements. The degree of kyphotic deformity and the degree of vertebral wedging deformity were measured on plain lateral radiographs. The spinal canal compromise was measured on computer tomography. The mean postoperative follow-up was 70 (24–108) months. The preoperative kyphosis averaged 25.7° and the mean sagittal index was 28.8°. The mean wedging deformity of the fractured vertebral body was 46% (24–66%). The mean preoperative spinal canal compromise secondary to retropulsed bony fragments was 64%. Immediately after surgery, the correction of kyphosis averaged 98%. There was no loss of correction at the final follow-up. A satisfactory reduction and good stabilisation with solid fusion were achieved in all cases.

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Résumé Entre 1991 et 2002 nous avons traité chirurgicalement 48 malades pour fractures communitives dorsolombaires associées à des lésions par étirement des éléments postérieurs. Le degré de cyphose et le degré de déformation angulaire vertébrale ont été mesurés sur les radiographies de profil. L'altération du canal vertébral a été mesurée sur la tomodensitométrie. La moyenne de suivi postopératoire était de 70 (24–108) mois. Les cyphose préopératoire était de 25,7° et l'index sagittal moyen était de 28,8°. La déformation angulaire moyenne du corps vertébral éclaté était de 46% (de 24 à 66%). Le rétrécissement moyen du canal vertébral secondaire au recul des fragments osseux étaient de 64%. Immédiatement après la chirurgie, la correction de la cyphose était en moyenne de 98%. Il n'y avait aucune perte de correction au dernier recul. Une réduction satisfaisante et une bonne stabilisation avec une fusion solide ont été obtenues dans tous les cas.

     

Spinal canal decompression in traumatic thoracolumbar burst fractures: posterior distraction rods versus transpedicular screw fixation.

Although the benefit of spinal canal decompression of traumatic thoracolumbar burst fractures is controversial, it remains a desirable procedure, as many reports describe improved neurologic outcome with spinal canal reconstruction. The optimal type of posterior instrumentation for reconstructing the spinal canal is unclear. This study focused on the efficacy of posterior distraction rods versus transpedicular screw fixation implants in decompressing the spinal canal and on the relationship between the amount of canal decompression and subsequent neurologic recovery. A medical records review was conducted to identify all patients surgically treated for traumatic burst fractures of the thoracolumbar spine from January 1, 1987 to June 30, 1989. Sixty-seven patients were selected by this review, and, of these, 30 had had both preoperative and postoperative CT scans. We could find no bias among patients who received both preoperative and postoperative CT scans as compared to those who did not, therefore the 30 patients were considered to be a random sample of the total population of 67. A retrospective study was then conducted on the 30 patients with surgically treated burst fractures--15 treated with posterior distraction rods and 15 treated with AO Fixator Interne transpedicular screw fixation implants. Preoperative and postoperative spinal canal cross-sectional areas were measured directly from the scaled CT scans. The area of most severe compromise was compared with an internal standard defined as the next, caudal, uncompromised spinal level, and the percentage of preoperative and postoperative canal compromise was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Canal clearance in burst fractures using the AO internal fixator.

The purpose of this study was to evaluate the ability of posterior distraction delivered by the AO internal fixator to effect a satisfactory reduction of the intraspinal fragments in burst fractures. The overall decompression achieved was from an initial compromise of 54% to a residual encroachment of 40%. Canal clearance proved most effective when carried out in the first 4 days, with an initial canal compromise of between 34 and 66%. The extent of improvement, even in this group, was not dramatic, with an average of 31% encroachment still remaining, with some cases as high as 50%. Therefore, we recommend that when canal clearance is essential, anterior decompression is the treatment of choice.     

Health-related quality of life after short segment instrumentation of lumbar burst fractures

Management of lumbar burst fractures remains controversial. Surgical reduction/stabilization is becoming more popular; however, the functional impact of operative intervention is not clear. The purpose of this study was to assess health-related quality of life and functional outcome after posterior fixation of lumbar burst fractures with either posterolateral or intrabody bone grafting. Twenty-four subjects were included. Radiographs and computed tomography scans were evaluated for deformity (kyphosis, vertebral compression, lateral angulation, lateral body height, and canal compromise) postoperatively, at 1 year, and at final follow-up (mean 3.2 years). Patients completed the SF 36 Health Survey and the Oswestry Low Back Pain Disability Questionnaire at final follow-up. Significant improvement was noted in midsagittal diameter compromise, vertebral compression, and kyphosis. The difference observed between the respondents mean scores on the SF 36 was not significantly different from those presented as the U.S. national average (p = 0.053). Data from the Oswestry questionnaire indicated a similarly high level of function. Overall, we found posterior spinal instrumentation to correlate with positive functional outcome based on both general health (SF 36) and joint-specific outcome scales (Oswestry). Posterior instrumentation provides sound canal decompression, kyphotic reduction, and maintains vertebral height with minimal transgression and long-term sequelae. In cases of severe initial deformity and neurologic compromise, intrabody bone grafting is most certainly indicated; the additional support provided by a posterolateral graft may also prove beneficial as an adjunct.     

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

Summary Background. 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. Method. 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. Findings. The mean posttraumatic loss of anterior vertebral body height was 58% (45–70%). The posttraumatic mean regional kyphosis was 16° and could be corrected by the posterior approach to a mean lordosis of 2°. Mean secondary loss of the kyphosis correction was 3° 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. Conclusion. 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.     

Low lumbar burst fractures: comparison between conservative and surgical treatments.

Twenty-two low lumbar burst fractures (L3-L5) were treated, with an average follow up of 56.2 and 39.0 months in the conservative and surgically treated groups, respectively. Twenty patients were available for review; seven were treated conservatively and 13 were stabilized surgically. All patients were evaluated clinically for work status, activity level, residual pain, and subsequent development of neurologic symptoms. Roentgenograms were reviewed for severity of initial fracture, canal compromise, and maintenance of initial correction. In general, neurologically intact patients in both groups returned to similar postinjury employment levels. Persistent back pain was found to be more disabling in the surgically treated group, in which a fusion incorporating four or five lumbar segments was performed. There was no evidence of significant loss of initial reduction, and no patients experienced late neurological compromise in the surgical group. An average follow-up kyphosis of 9.2 degrees and 31% loss of vertebral height were observed in the conservative group, while a follow-up lordosis of 1 degree and 19% loss of vertebral height were observed in the surgical group. Conservative treatment of low lumbar burst fracture is a viable option in neurologically intact patients, but loss of lordosis and vertebral height may persist. Biomechanical and anatomic characteristics of the low lumbar spine differ from the thoracolumbar region and may account for the inherent stability of these injuries. If surgery is chosen, a long fusion with distraction instrumentation should be avoided in the low lumbar spine. A short rigid fixation with pedicular instrumentation may be of greater benefit.