Load-sharing Classification Research Articles

Radiologic and Functional Outcomes in Unstable Thoracolumbar Fractures Treated With Short-segment Pedicle Instrumentation.

A retrospective review of radiographs, clinical charts, and health questionnaires of 40 patients. To evaluate the radiologic and functional results of unstable thoracolumbar fractures treated with short-segment pedicle instrumentation (SSPI). Although earlier publications report a risk of correction loss or material failure after short-segment fixation in unstable thoracolumbar fractures, more current data suggest that improvements in this technique could offer good clinical and radiologic results. We undertook a retrospective review of 40 patients with unstable thoracolumbar fractures treated with SSPI. Radiographs and computed tomogrphic scans were analyzed to determine fracture classification and sagittal plane deformity, estimated by the Cobb method. The rates of final kyphosis and correction loss and their relationship with the Load Sharing Classification (LSC) and the AO classification were analyzed. We reviewed the hospital charts to identify complications and outcomes. At the final follow-up, the Short-Form 36 health survey was carried out to evaluate the functional outcome. The relationship between conditions such as polytrauma, neurological compromise or fracture site, and radiological and functional outcomes was also analyzed. We observed mean values of 5.9 degrees of final follow-up kyphosis and 5.1 degrees of correction loss. One case of material failure was seen. The severity in the LSC or the AO classification, polytrauma, neurological compromise, or fracture site had no relationship with worse radiologic or functional outcomes. SSPI shows good results in fracture reduction, with good functional outcomes despite the loss of correction seen at the final follow-up. Although no investigated variable was found to be predictive of radiographic failure, a trend was identified (P=0.07) that patients with a higher LSC had an increased loss of correction.

The Correlation Between Vertical Laminar Fractures and the Severity of Associated Burst Fractures.

Patients with laminar fractures have a higher chance of experiencing severe trauma and neurologic deficit. In previous studies, laminar fractures were divided into different types based on the axial plane of computed tomographic scans. No report described the morphology of vertical laminar fractures in the coronal plane. Furthermore, the correlation between a specific type of laminar fracture and the extent of severity of thoracolumbar (TL) burst fractures has rarely been mentioned. A retrospective evaluation of 341 patients with TL burst fractures with or without laminar fractures were divided into 6 groups based on the morphology observed across reconstructed coronal and axial computed tomographic planes. The Thoracolumbar Injury Classification and Severity Score (TLICS), Load Sharing Classification (LSC), and American Spinal Injury Association (ASIA) impairment scale were evaluated for each patient. Intergroup comparisons were also performed for all metrics. The TLICS, LSC, and ASIA impairment scale were determined for each laminar fracture group. Statistical differences were found in most intergroup comparisons across all metrics. Significantly higher injury scores were observed in the groups with a more severe coronal and axial laminar fracture, and the injury severity in the coronal scan played a more decisive role. The morphology of vertical laminar fractures as observed across multiple image planes was more complex and accurate than an analysis based solely on the axial plane. Different morphologies indicated differences in the severity of associated TL burst fractures. The laminar fracture in the coronal plane was associated with the severity of spinal injury.

Vertebral body spread in thoracolumbar burst fractures can predict posterior construct failure

Background ContextThe load sharing classification (LSC) laid foundations for a scoring system able to indicate which thoracolumbar fractures, after short-segment posterior-only fixations, would need longer instrumentations or additional anterior supports. PurposeWe analyzed surgically treated thoracolumbar fractures, quantifying the vertebral body's fragment displacement with the aim of identifying a new parameter that could predict the posterior-only construct failure. Study DesignThis is a retrospective cohort study from a single institution. Patient SampleOne hundred twenty-one consecutive patients were surgically treated for thoracolumbar burst fractures. Outcome MeasuresGrade of kyphosis correction (GKC) expressed radiological outcome; Oswestry Disability Index and visual analog scale were considered. MethodsOne hundred twenty-one consecutive patients who underwent posterior fixation for unstable thoracolumbar burst fractures were retrospectively evaluated clinically and radiologically. Supplementary anterior fixations were performed in 34 cases with posterior instrumentation failure, determined on clinic-radiological evidence or symptomatic loss of kyphosis correction. Segmental kyphosis angle and GKC were calculated according to the Cobb method. The displacement of fracture fragments was obtained from the mean of the adjacent end plate areas subtracted from the area enclosed by the maximum contour of vertebral fragmentation. The “spread” was derived from the ratio between this subtraction and the mean of the adjacent end plate areas. Analysis of variance, Mann-Whitney, and receiver operating characteristic were performed for statistical analysis. The authors report no conflict of interest concerning the materials or methods used in the present study or the findings specified in this paper. No funds or grants have been received for the present study. ResultsThe spread revealed to be a helpful quantitative measurement of vertebral body fragment displacement, easily reproducible with the current computed tomography (CT) imaging technologies. There were no failures of posterior fixations with preoperative spreads <42% and losses of correction (LOC)<10°, whereas spreads >62.7% required supplementary anterior supports whenever LOC>10° were recorded. Most of the patients in a “gray zone,” with spreads between 42% and 62.7%, needed additional anterior supports because of clinical-radiological evidence of impending mechanical failures, which developed independently from the GKC. Preoperative kyphosis (p<.001), load sharing score (p=.002), and spread (p<.001) significantly affected the final surgical treatment (posterior or circumferential). ConclusionsTwenty-two years after the LSC, both improvements in spinal stabilization systems and software imaging innovations have modified surgical concepts and approach on spinal trauma care. Spread was found to be an additional tool that could help in predicting the posterior construct failure, providing an objective preoperative indicator, easily reproducible with the modern viewers for CT images.

Short term radiological outcome of inserting screw at fracture level in posterior short segment fixation in thoracolumbar burst fractures

Background: Unstable thoracolumbar burst fractures are treated surgically by short segment fixation but may be associated with high implant failure. Supplementation of anterior column by insertion of screw at fracture site makes it more biomechanically stable.Objectives: The purpose of this prospective study was to evaluate radiological parameters in thoracolumbar fractures treated with intermediate screw fixation with a minimum follow up of two years.Methods: This prospective study was conducted from 2011 till 2012 where unstable thoracolumbar fractures treated with short segment posterior instrumentation with screw at fracture site were evaluated. All patients (average age 34.64 were followed up for at least 24 months and were classified according to Thoracolumbar Injury Classification and Severity Score and load sharing classifi cation. Out of total 32 patients, four lost to follow up. Radiological parameters like vertebral body height and segmental kyphosis were evaluated and pain was evaluated by Visual Analogue Scale score.Results: Preoperative pain showed mean Visual Analogue Scale Score score of 8.29 that improved to 0.97 at fi nal follow up. Average preoperative loss of vertebral body height was 48.19 %, which improved to 11.4 % after surgery (p&lt;.001). Final vertebral body collapse was 12.98 % with mean percentage loss of vertebral height at 1.57%. Average segmental kyphotic angle was 22.54 before surgery, which corrected to 5.89 immediately after surgery (p&lt;0.001). Final segmental kyphosis was 8.46. Loss of kyphosis correction was 2.57. Two patients had implant failure, but was solidly united during implant removal in both cases.Conclusion: Excellent maintenance of reduction in thoracolumbar burst fractures with short segment fixation with intermediate screws at fracture site with limited decompression resulted in improved neurologic function and satisfactory clinical outcomes, with a low incidence of implant failure and progressive deformity.

Nine issues about clinical application of thoracolumbar injury classification and severity score

Spinal fractures are a big challenge to orthopedists. Thoracolumbar Injury Classification and Severity Score (TLICS), a newly developed evaluation system for thoracolumbar fractures, has proved to be valid and reliable in the last decade. However, there have still been many problems in the clinical application of TLICS in China. We discussed nine issues about the clinical application of TLICS in this article, hoping to promote better understanding and application of TLICS in Chinese spinal surgeons in their daily practice. Key words: Thoracic verterae; Lumber verterae; Fractures,bone; Posterior ligament complex; Load-sharing classification score

Risk factor analysis for predicting vertebral body re-collapse after posterior instrumented fusion in thoracolumbar burst fracture

Background ContextIn the posterior instrumented fusion surgery for thoracolumbar (T-L) burst fracture, early postoperative re-collapse of well-reduced vertebral body fracture could induce critical complications such as correction loss, posttraumatic kyphosis, and metal failure, often leading to revision surgery. Furthermore, re-collapse is quite difficult to predict because of the variety of risk factors, and no widely accepted accurate prediction systems exist. Although load-sharing classification has been known to help to decide the need for additional anterior column support, this radiographic scoring system has several critical limitations. Purpose(1) To evaluate risk factors and predictors for postoperative re-collapse in T-L burst fractures. (2) Through the decision-making model, we aimed to predict re-collapse and prevent unnecessary additional anterior spinal surgery. Study DesignRetrospective comparative study. Patient SampleTwo-hundred and eight (104 men and 104 women) consecutive patients with T-L burst fracture who underwent posterior instrumented fusion were reviewed retrospectively. Burst fractures caused by high-energy trauma (fall from a height and motor vehicle accident) with a minimum 1-year follow-up were included. The average age at the time of surgery was 45.9 years (range, 15–79). With respect to the involved spinal level, 95 cases (45.6%) involved L1, 51 involved T12, 54 involved L2, and 8 involved T11. Mean fixation segments were 3.5 (range, 2–5). Pedicle screw instrumentation including fractured vertebra had been performed in 129 patients (62.3%). Outcome MeasuresClinical data using self-report measures (visual analog scale score), radiographic measurements (plain radiograph, computed tomography, and magnetic resonance image), and functional measures using the Oswestry Disability Index were evaluated. MethodsBody height loss of fractured vertebra, body wedge angle, and Cobb angle were measured in serial plain radiographs. We assigned patients to the re-collapse group if their body height loss progressed greater than 20% at any follow-up time compared with immediate postoperative body height loss; we assigned the remaining patients to the well-maintained group. The chi-square test and t test of SPSS were used for comparison of differences between two groups and multiple logistic regression analysis for risk factor evaluation. Through the decision tree analysis of statistical package R, a decision-making model was composed, and a cutoff value of revealed risk factors and re-collapse rate of each subgroup were identified. The present study wassupported by the University College of Medicine Research Fund (university to which authors belong). There was no external funding source for this study. The authors have no conflict of interest to declare. ResultsRe-collapse occurred in 31 of 208 patients (14.9%). In this group, age, the proportion of male gender, preoperative height loss, and preoperative wedge angle were significantly greater than the well-maintained group. Multivariable logistic regression analysis identified two independent risk factors: age (adjusted odds ratio 1.084, p=.002) and body height loss (adjusted odds ratio 1.065, p=.003). According to the decision-making tree, age (>43 years) was the most discriminating variable, andpreoperative body height loss (>54%) was the second. In this model, the re-collapse rate was zero in ages less than 43 years, and among those remaining, nearly 80% patients with greater than 54% of body height loss belonged to the re-collapse group. ConclusionsThe independent predictors of re-collapse after posterior instrumented fusion for T-L burst fracture were the age at operation (>43 years old) and preoperative body height loss (>54%). Careful assessment using our decision-making model could help to predict re-collapse and prevent unnecessary additional spinal surgery for anterior column support, especially in young patients.

Percutaneous pedicle screw fixation and minimally invasive decompression in the same incision for type A3 thoracolumbar burst fracture

To assess the effectiveness of percutaneous pedicle screw fixation and minimally invasive decompression in the same incision for type A3 thoracolumbar burst fracture. Between May 2014 and February 2016, 43 cases of type A3 thoracolumbar burst fracture with or without nerve symptoms were treated with pedicle screw fixation and neural decompression. Of them, 21 patients underwent percutaneous pedicle screw fixation and minimally invasive decompression in the same incision (percutaneous group), and the other 22 patients underwent traditional open surgery (open group). There was no significant difference in gender, age, cause of injury, fractures level, preoperative American Spinal Injury Association (ASIA) grade, thoracolumbar injury classification and severity (TLICS) score, load-sharing classification, height of injury vertebrae, kyphotic Cobb angle, and spinal canal encroachment between 2 groups ( P>0.05). The length of soft tissue dissection, operation time, intraoperative blood loss, postoperative drainage, X-ray exposure times, and incision visual analogue scale (VAS) score at 1 day after operation were recorded and compared. At last follow-up, Japanese Orthopaedic Association (JOA) score and low back pain VAS score were recorded and compared respectively. The ASIA grade recovery was evaluated; the height of injury vertebrae, kyphotic Cobb angle, and spinal canal encroachment were assessed postoperatively. Percutaneous group was significantly better than open group in the length of soft tissue dissection, intraoperative blood loss, postoperative drainage, and incision VAS at 1 day after operation ( P<0.05), but no significant difference was found in operation time between 2 groups ( P>0.05); however, X-ray exposure times of open group were significantly better than that of percutaneous group ( P<0.01). The patients were followed up 12 to 19 months (mean, 15.1 months) in 2 groups. All patients achieved effective decompression. No complications of iatrogenic neurological injury and internal fixation failure occurred. The height of injury vertebrae, kyphotic Cobb angle, and spinal canal encroachment of the fractured vertebral body were significantly improved at 3 days after operation when compared with preoperative ones ( P<0.05), but no significant difference was found between 2 groups ( P>0.05). At last follow-up, JOA score and low back pain VAS score of percutaneous group were significantly better than those of open group ( P<0.05). The neurological function under grade E was improved at least one ASIA grade in 2 groups, but no significant difference was shown between 2 groups ( Z=0.480, P=0.961). Percutaneous pedicle screw fixation and minimally invasive decompression in the same incision for type A3 thoracolumbar burst fracture has satisfactory effectiveness. And it has the advantages of minimal trauma, quick recovery, safeness, and reliableness.

Temporary short-segment pedicle screw fixation for thoracolumbar burst fractures: comparative study with or without vertebroplasty

Background ContextShort-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. PurposeThe purpose of the study we report here was to compare outcomes for temporary short-segment pedicle screw fixation with vertebroplasty and for such fixation without vertebroplasty. Study DesignThis is a prospective multicenter comparative study. Patient SampleWe studied 62 consecutive patients with thoracolumbar burst fracture who underwent short-segment posterior instrumentation using ligamentotaxis with Schanz screws with or without vertebroplasty. Outcome MeasuresRadiological parameters (Cobb angle on standing lateral radiographs) were used. MethodsImplants were removed approximately 1 year after surgery. Neurologic function, kyphotic deformity, canal compromise, and fracture severity were evaluated prospectively. ResultsAfter surgery, all patients with neurologic deficit had improvement equivalent to at least one grade on the American Spinal Injury Association impairment scale and had fracture union. Kyphotic deformity was reduced significantly, and reduction of the vertebrae was maintained with and without vertebroplasty, regardless of load-sharing classification. Although no patient required additional anterior reconstruction, kyphotic change was observed at disc level mainly after implant removal with or without vertebroplasty. ConclusionsTemporary short-segment fixation yielded satisfactory results in the reduction and maintenance of fractured vertebrae with or without vertebroplasty. Kyphosis recurrence may be inevitable because adjacent discs can be injured during the original trauma.

Comparison of efficacy of KumaFix posterior spinal screw / rod system and posterior U-shape screw / rod system for treatment of thoracolumbar vertebral body fractures

Objective To compare the efficacy of KumaFix posterior spinal screw/rod system (KumaFix system) and posterior U-shape screw/rod system for treatment of thoracolumbar vertebral body fractures. Methods A total of 131 patients with thoracolumbar vertebral body fractures treated from January 20ll to July 2011 were prospectively analyzed. All patients showed thoracolumbar injury classification and severity score (TLICS) more than 5 points and spinal load-sharing classification (LSC) score of 4-6. The patients were assigned to two groups according to the coin toss method: group A (n=72, treated with reduction and fixation with KumaFix system in combination with transpedicular bone grafting of fractured vertebrae) and group B (n=59, submitted to posterior reduction and fixation with U-shaped screw/rod system in combination with transpedicular bone grafting of fractured vertebrae). In group A, there were 41 male and 31 female patients at age of (41.2±4.9)years (range, 20-53 years). In group B, there were 33 male and 26 female patients at age of(40.6±4.5)years (range, 21-51 years). The two groups were analyzed and compared in aspects of operation time, blood loss, anterior vertebral height ratio, middle vertebral height ratio, posterior vertebral height ratio, kyphosis angle, Oswestry disability index (ODI) and incidence of adjacent segment degeneration. Results All patients were followed up for mean 5.3 years (range, 5.1-5.8 years). Operation time and blood loss were (72.5±21.8)min and (320.6±90.0)ml in group A, less than (104.3±20.7)min and (421.0±84.5)ml in group B ( P<0.05). Both groups achieved obvious improvements in anterior vertebral height ratio, middle vertebral height ratio, posterior vertebral height ratio and kyphosis angle after operation(P<0.05). At the last follow-up, the middle vertebral height ratio was (92.0±2.8)% in group A, better than (84.1±5.1)% in group B (P<0.05). Both groups showed improvement in ODI after operation(P<0.05). At the last follow-up, ODI and incidence of adjacent segment degeneration were 11.9±7.1 and 0 in group A, decreased compared to 20.9±6.7 and 12% in group B (P<0.05). Conclusions For thoracolumbar vertebral body fractures, the KumaFix system has better reduction effect than U-shape screw/rod system. Meanwhile, the KumaFix system can avoid negative effect. Key words: Spinal fractures; Thoracic vertebrae; Lumbar vertebrae; KumaFix system

Factors predicting long-term outcome after short-segment posterior fixation for traumatic thoracolumbar fractures.

Background:The “gold standard” for instrumentation of unstable thoracolumbar fracture-dislocations is pedicle screw and rod fixation. Although traditional treatment supports long-segment posterior fixation (LSPF), more recent studies show short-segment posterior fixation (SSPF) may be effective, but incur higher failure rates. Here, we evaluated the effectiveness of SSPF in the management of unstable thoracolumbar injuries and analyzed the factors impacting long-term outcomes.Methods:In this retrospective analysis of 91 patients with thoracolumbar fractures managed with SSPF alone, we assessed the clinical and radiological parameters at preoperative, postoperative, and follow-up intervals along with reasons for failures of SSPF.Results:We analyzed 91 patients (mean age: 33.5 years; Male: Female = 50:41) with thoracolumbar fractures treated with SSPF over a median follow-up period of 30 months. SSPF failures were observed in 26 of 91 (28.6%) patients; the median time to implant failure was 17 months. On univariate analysis, statistically significant factors contributing to failure of SSPF included the presence of a burst fracture, a preoperative LSC (load-sharing classification) score >6, and translation/dislocation. With multinomial regression analysis, the only factor predictive for SSPF failure was the patients' postoperative ambulatory status.Conclusion:Patients with thoracolumbar facture dislocations, subjected to axial spinal loading postoperatively, should not be considered for SSPF alone. The following factors also contributed to SSPF failures: a burst fracture, a preoperative LSC score of >6, and/or presence of transverse dislocation.

Posterior short-segment fixation in thoracolumbar unstable burst fractures – Transpedicular grafting or six-screw construct?

ObjectivesEarly implant failure and donor-site complication remain a concern in patients with thoracolumbar burst fracture underwent one-above and-below short-segment posterior pedicle screw fixation with fusion. Our aim was to evaluate the results of short-segment pedicle instrumentation enforced by two augmenting screws or injectable artificial bone cement in the fractured vertebra, and compare the differences between these two Patients and methodsWe conducted a retrospective clinical and radiographic study. Twenty-seven patients were treated with a six-screw construct (group 1), and twenty-nine patients underwenta four-screw construct and fractured vertebra augmentation by injectable calcium sulfate/phosphate cement (group 2). Posterior or posterolateral fusions were not performed in both groups. The severity of the fractured vertebra was evaluated by the load-sharing classification (LSC). Local kyphosis and anterior body height of the fractured vertebra were measured and were follow-up at least 2 years. Any implant failure or loss of correction >10° degrees at the final was defined as failure of surgery. Patients’ clinical results were assessed by the Denis scale. ResultsBlood loss and operation time were less in group 1 (126.2±9.7 vs. 267.6±126.1ml, p<0.001 and 141.2±48.7 vs. 189.8±16.4min, p<0.001). Immediately after surgery, group 2 had a better local kyphosis angle (3.7±5.3 vs.6.0±4.1°, p=0.047) and acquired more anterior body height (94.9%±7.6% vs. 84.9%±10.0%, p<0.001). Both groups had similar clinical results (pain score: 1.5±0.8vs. 1.4±0.6, p=0.706; work score: 1.7±0.9 vs. 1.6±1.0, p=0.854). Group 1 had 3 cases of surgery failure; group 2 had 8 cases of implant failure (p=0.121). The average LSC score of these 11 patients with surgical failure was 7.2. ConclusionThesix-screw construct had the advantage of shorter operating time, less blood loss, and lower failure rate. For those patients with anLSC score ≧7, posterior short-segment instrumentation should be used cautiously.

Intermediate screws in short segmental pedicular fixation for thoracolumbar fractures. Retrospective study Of 4 and 6-screw constructs

Introduction Short segment pedicle screw fixation is the most common treatment for thoracolumbar fractures. However, it may not be adequate to achieve and maintain reduction of the fracture and is associated with a high rate of failure. Additional procedures have been offered as alternative solutions to prevent this failure. Long segmental instrumentation or placements of screws at fracture site are some alternatives. Correction of sagittal deformity is important for the maintenance of fracture reduction and may have an effect on functional outcome. Intraoperative correction of sagittal deformity and fracture reduction can be managed easily through placement of screws at the fracture level. Objectives The purpose of this retrospective study was to evaluate the efficacy of screw placement at the fracture level in correction of deformity, maintenance of correction and preventing the failure of fixation in thoracolumbar fractures. Methods Retrospective study of patients with thoracolumbar fractures treated with 4 or 6-screw construct. Preoperative, postoperative and follow-up were evaluated. To evaluate the efficacy of fracture level screw fixation anterior vertebral height compression (%ABC), local kyphosis (KA) and load-sharing classification were compared. %ABC was calculated by using the formula adopted by Mumford et al. Local kyphosis was measured according to Cobb's method. Student t test was used for statistical analysis of variables. A p-value < 0.05 was considered statistically significant. Results The load-sharing classification was similar between the groups. The preoperative KA was statistically similar between groups (P = 0.552). The percentage of KA correction was lowest in the 4-screw construct group (P = 0.034). During follow-up, KA correction was more maintained in 6-screw construct group (P = 0.045). The average preoperative %ABC was similar in groups (P = 0.855). %ABC was more maintained in 6-screw construct group during follow-up. Conclusion Segmental fixation of fractures with screws at the level of fracture offers improved biomechanical stability and provides for additional fixation points that may aid in reduction. The 6-screw construct yields excellent results with a very low rate of failure.

Biomechanical evaluation of monosegmental pedicle instrumentation in a calf spine model and the role of fractured vertebrae in screw stability.

BackgroundMonsegmental pedicle instrumentation (MSPI) has been used to treat thoracolumbar fractures. However, there are few reports about the biomechanical characteristics of MSPI compared with traditional short-segment pedicle instrumentation (SSPI) in management of unstable thoracolumbar fractures, and the influence of vertebral fracture on screw stability is still unclear.MethodsThis study was to compare the immediate stability between MSPI and SSPI in management of unstable L1 fracture, and to evaluate the role of fractured vertebrae in screw stability. Two studies were performed: in the first study, sixteen fresh calf spines (T11-L3) were divided into two groups, in which unstable fractures at L1 were produced and then instrumented with MSPI or SSPI respectively. The range of motion (ROM) and lax zone (LZ) of specimens were evaluated with pure moment of 6 Nm loaded. The second study measured and compared the pullout strength of screws inserted in to 16 intact and fractured vertebrae of calf spines (L1-3) respectively. The correlation of pullout strength with load sharing classification (LSC) of fractured vertebrae was analyzed.ResultsNo significant difference in the ROM and LZ of the destabilized segments after fixation between MSPI and SSPI, except in axial rotation of ROM (P < 0.05). After fatigue cyclic loading, the MSPI showed a significant increase of ROM during lateral bending and axial rotation (P < 0.05); however, there were no significant differences in the LZ during all loading models between groups (P > 0.05). The mean pullout strength of pedicle screws in fractured vertebrae decreased by 13.7 %, compared with that of intact vertebrae (P > 0.05), and had a low correlation with LSC of the fractured vertebrae (r = 0.293, P > 0.05).ConclusionsMSPI can provide effective immediate stability for management of unstable thoracolumbar fractures; however, it has less fatigue resistance during lateral bending and axial rotation compared with SSPI. LSC score of fractured vertebrae is not a major influence on the pullout strength of screws.

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.

Nonoperative Management in Neurologically Intact Thoracolumbar Burst Fractures: Clinical and Radiographic Outcomes.

Retrospective cohort study. The identification of factors that lead to the failure of nonoperative management in neurologically intact thoracolumbar burst fractures. The treatment of thoracolumbar burst fractures (TLBF) can be controversial, particularly in the neurologically intact. Surgery for intact burst fractures has been advocated for early mobilization and a shorter hospital stay. These goals, however, have not always been achieved, rejuvenating an interest in nonoperative treatment. Sixty-eight neurologically intact patients with burst fractures of the thoracolumbar junction (T11-L2), and a thoracolumbar injury classification and severity score (TLICS) of 2, were treated at our institution. Based on CT scans, patients were scored based on the load-sharing classification (LSC) scale. Initial treatment consisted of bracing in clamshell thoracolumbar orthosis and gradual mobilization. Owing to pain limiting mobilization, 18 patients failed nonoperative management and required instrumentation. Those who failed nonsurgical management were significantly more kyphotic (8° ± 10) and stenotic (52% ± 14%) than those successfully treated nonoperatively (3° ± 7 and 63 ± 12%, respectively). The LSC score of those undergoing surgery (6.9 ± 1.1) was also greater than those successfully treated nonoperatively (5.8 ± 1.3, P = 0.006). Length of hospitalization was longer, and hospital charges higher in those requiring surgery compared to the nonoperative group. At follow-up there was no difference between groups in the visual analog score for pain (VAS) or the Oswestry disability index. Owing to pain limiting mobilization, a quarter of neurologically intact patients with thoracolumbar burst fractures and a TLICS score of 2 failed nonsurgical management. The greater the kyphosis, stenosis, and fragmentation of the fracture, the more likely patients required surgery. In addition to the TLICS classification, other radiographic and clinical parameters should be included in selecting appropriate treatment strategy. The cost savings with nonoperative treatment of intact burst fractures, when appropriate, are significant.

Can the Interspinous Distance Predict Kyphosis in Conservative Treatment in Thoracolumbar Burst Fracture? A Retrospective, Diagnostic Study

Study Design: Retrospective, diagnostic study. Objective: To verify if the interspinous distance is able to predict the risk for kyphotic collapse in thoracolumbar burst fractures treated conservatively without neurological deficit. Summary of Background Data: In patients with thoracolumbar burst fractures, the association between the amount of comminution, by using load-sharing classification (LSC), and kyphotic collapse is presented in the literature. However, LSC does not include the interspinous distance as an indirect sign to suggest biomechanical instability due to posterior ligamentous disruption in these patients in order to predict kyphotic collapse. Methods: We added the interspinous distance to the load-sharing classification (MLSC) in 50 consecutive patients with thoracolumbar burst fractures (according to Denis criteria) treated conservatively. Results: The LSC score was correlated to kyphotic collapse in the patients treated with TLSO (r = 0.312, p = 0.027; Spearman test; A = 0.668). The MLSC was similarly correlated to kyphotic collapse among TLSO-treated patients (r = 0.295, p = 0.038; Spearman test; A = 0.652). Conclusions: The interspinous distance did not contribute to the identification of worse radiographic outcomes, represented by the kyphotic collapse. This may suggest that the amount of comminution pointed out by the LSC is enough and more important than the interspinous opening in order to predict kyphotic collapse in thoracolumbar burst fractures. Possibly, the interspinous distance is much too heterogenous and multifactorial to be useful, since it reflects vertebral body height, preinjury anatomy, as well as posterior element disruption.

More than 5-Year Follow-up Results of Two-Level and Three-Level Posterior Fixations of Thoracolumbar Burst Fractures with Load-Sharing Scores of Seven and Eight Points.

BackgroundThe development of pedicle screw-based posterior spinal instrumentation is recognized as one of the major surgical treatment methods for thoracolumbar burst fractures. However, the appropriate level in posterior segment instrumentation is still a point of debate. To assesses the long-term results of two-level and three-level posterior fixations of thoracolumbar burst fractures that have load-sharing scores of 7 and 8 points.MethodsFrom January 1998 to May 2009, we retrospectively analyzed clinical and radiologic outcomes of 45 patients with thoracolumbar burst fractures of 7 and 8 points in load-sharing classification who were operated on using two-level posterior fixation (one segment above and one segment below: 28 patients, group I) or three-level posterior fixation (two segments above and one segment below: 17 patients, group II). Clinical results included the grade of the fracture using the Frankel classification, and the visual analog score was used to evaluate pain before surgery, immediately after surgery, and during follow-up period. We also evaluated pain and work status at the final follow-up using the Denis pain scale.ResultsIn all cases, non-union or loosening of implants was not observed. There were two screw breakages in two-level posterior fixation group, but bony union was obtained at the final follow-up. There were no significant differences in loss of anterior vertebral body height, correction loss, or change in adjacent discs. Also, in clinical evaluation, there was no significant difference in the neurological deficit of any patient during the follow-up period.ConclusionsIn our study, two-level posterior fixation could be used successfully in selected cases of thoracolumbar burst fractures of 7 and 8 points in the load-sharing classification.

Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures

Background contextTraditional short-segment fixation of unstable thoracolumbar injuries can be associated with progressive kyphosis and implant failure. Load sharing classification (LSC) recommends supplemental anterior reconstruction for fractures of score 7 or greater. Posterior fixation including the fractured vertebra (PFFV) has biomechanical advantages over conventional short-segment fixation. However, its efficacy in severe thoracolumbar injuries (LSC≥7) has not been studied. PurposeTo study the clinical, functional, and radiologic results of PFFV for severe, unstable thoracolumbar injuries (LSC≥7) at a minimum of 2 years. Study designA retrospective review of case records. Patient sampleThirty-two patients with an unstable burst fracture of LSC≥7 treated with PFFV were included. Outcome measuresThey included clinical outcomes: American Spinal Injury Association grade, visual analog scale (VAS), Oswestry Disability Index (ODI); and radiologic measures: segmental kyphosis angle, vertebral wedge angle, and percentage loss of anterior and posterior vertebral height. MethodsThirty-two patients with LSC≥7 who had undergone PFFV, with a minimum follow-up of 2 years were studied for demographic, injury, and surgical details. Clinical and radiologic outcomes were measured before surgery and at 6, 12, and 24 months postoperatively. The presence of screw breakage, screw pullout, peri-implant loosening, and rod breakage were considered as criteria for implant failure. ResultsNone of the patients had postoperative implant failure at the final follow-up. The mean preoperative kyphosis angle was 22.9°±7.6°. This improved significantly to 9.2°±6.6° after surgery (p=.000). There was a loss of mean 2.4° (mean kyphosis angle of 11.6°±6.3°) at the final follow-up. The mean preoperative wedge angle was 23.0°±8.1°. This was corrected to 9.7°±6.2° (p=.000). There was a loss of kyphosis (mean 1.2°) in the follow-up period. The mean anterior and posterior vertebral height also showed significant improvements postoperatively, which were maintained at the final follow-up. The mean ODI and VAS scores at the end of 2 years were 17.5% and 1.6, respectively. ConclusionsReduction of unstable thoracolumbar injuries even with LSC≥7 can be achieved and maintained with the use of short-segment pedicle screw fixation including the fractured vertebra, avoiding the need for anterior reconstruction. In the current era of evolving concepts of fracture fixation, the relevance of LSC in the management of unstable burst fractures is questionable.

Short segment pedicle screw instrumentation with an index level screw and cantilevered hyperlordotic reduction in the treatment of type-A fractures of the thoracolumbar spine

The purpose of this study was to evaluate and compare the effect of short segment pedicle screw instrumentation and an intermediate screw (SSPI+IS) on the radiological outcome of type A thoracolumbar fractures, as judged by the load-sharing classification, percentage canal area reduction and remodelling. We retrospectively evaluated 39 patients who had undergone hyperlordotic SSPI+IS for an AO-Magerl Type-A thoracolumbar fracture. Their mean age was 35.1 (16 to 60) and the mean follow-up was 22.9 months (12 to 36). There were 26 men and 13 women in the study group. In total, 18 patients had a load-sharing classification score of seven and 21 a score of six. All radiographs and CT scans were evaluated for sagittal index, anterior body height compression (%ABC), spinal canal area and encroachment. There were no significant differences between the low and high score groups with respect to age, duration of follow-up, pre-operative sagittal index or pre-operative anterior body height compression (p = 0.217, 0.104, 0.104, and 0.109 respectively). The mean pre-operative sagittal index was 19.6° (12° to 28°) which was corrected to -1.8° (-5° to 3°) post-operatively and 2.4° (0° to 8°) at final follow-up (p = 0.835 for sagittal deformity). No patient needed revision for loss of correction or failure of instrumentation. Hyperlordotic reduction and short segment pedicle screw instrumentation and an intermediate screw is a safe and effective method of treating burst fractures of the thoracolumbar spine. It gives excellent radiological results with a very low rate of failure regardless of whether the fractures have a high or low load-sharing classification score.

Viability and long-term survival of short-segment posterior fixation in thoracolumbar burst fractures

Background contextShort-segment pedicle screw instrumentation constructs for the treatment of thoracolumbar fractures gained popularity in the 1980s. The load-sharing classification (LSC) is a straightforward way to describe the extent of bony comminution, amount of fracture displacement, and amount of correction of kyphotic deformity in a spinal fracture. There are no studies evaluating the relevance of fracture comminution/traumatic kyphosis on the long-term radiologic outcome of burst fractures treated by short-segment instrumentation with screw insertion in the fractured level. PurposeTo evaluate the efficacy of the six-screw construct in the treatment of thoracolumbar junction burst fractures and the influence of the LSC score on the 2-year radiologic outcome. Study designCase series of consecutive patients of a single university hospital. Patient sampleConsecutive patients from one university hospital with nonosteoporotic thoracolumbar burst fractures. Outcome measuresBeing a radiology-based study, the outcome measures are radiologic parameters (regional kyphosis [RK], local kyphosis, and thoracolumbar kyphosis [TLK]) that evaluate the degree and loss of correction. MethodsRetrospective analysis of all consecutive patients with nonosteoporotic thoracolumbar burst fractures managed with a six-screw construct in a single university hospital, with more than 2 years' postoperative follow-up. ResultsEighty-six patients met the inclusion criteria, and 72 (83.7%) with available data were ultimately included in the study. The sample included 53 men and 19 women, with a mean (standard deviation [SD]) age of 35.6 years (14.4 years) at the time of surgery. Mean LSC score was 6.3 (SD 1.6, range 3–9). Forty-four of 62 (70.9) fractures had a score greater than 6. Mean (SD) RK and TLK deteriorated significantly during the first 6 months of follow-up: 2.90° (4.54°) p=.005 and 2.78° (6.45°) p=.069, respectively. Surgical correction correlated significantly (r=0.521, p<.0001) with the time elapsed until surgery. Loss of surgical correction (postoperative to 6-month RK and TLK increase) correlated significantly with the LSC score (r=0.57, p=.004; r=0.51, p=.022, respectively). Further surgery because of correction loss was not required in any case. ConclusionsThe six-screw construct is effective for treating thoracolumbar junction burst fractures. The medium-to-long-term loss of correction is affected by the amount of bony comminution of the fracture, objectified through the LSC score.