Gertzbein and load sharing classifications for unstable thoracolumbar fractures

Analysis of factors associated with the failure of treatment in thoracolumbar burst fractures treated with short-segment posterior spinal fixation

BACKGROUND

The treatment of thoracolumbar burst fractures continues to pose challenges. Although short-segment posterior spinal fixation (SSPSF) has shown satisfactory clinical outcomes, it is accompanied by a relatively high rate of treatment failure. This study aimed to assess factors associated with treatment failure in thoracolumbar burst fractures treated with SSPSF.

METHODS

The clinical data of 241 consecutive patients with a traumatic thoracolumbar burst fracture who underwent SSPSF at our center between Apr 2016 and Apr 2021 were retrospectively reviewed. Patients were divided into two groups (failure of the treatment group and non-failure of the treatment group). We compared potential risk factors for the failure of treatment including age, gender, body mass index, smoking, diabetes, vertebral body compression rate, use of crosslinks, percentage of anterior height compression, presence of index level instrumentation, Cobb angle, interpedicular distance (IPD), canal compromise, Load Sharing Classification (LSC) score, use of posterolateral fusion, and pain intensity between the two groups.

RESULTS

A sum of 137 (56.8%) males and 104 (43.2%) females were enrolled where the mean age and follow-up of the participants were 48.34 ± 10.23 years and 18.67 ± 5.23 months, respectively. Treatment failure was observed in 34 cases (14.1%). The results of the binary logistic regression analysis revealed that the lack of index level instrumentation (OR 2.21; 95% CI 1.78-3.04; P = 0.014), LSC score (odds ratio [OR] 2.64; 95% confidence interval [95% CI], 1.34-3.77; P = 0.007), and IPD (OR 1.77; 95% CI 1.51-2.67; P = 0.023) were independently associated with a higher rate of failure of treatment.

CONCLUSIONS

The findings of this study revealed that increased rates of treatment failure in thoracolumbar burst fractures treated with SSPSF were associated with factors such as the absence of index level instrumentation, higher LSC scores, and larger IPD. These findings could be helpful in the proper management of patients with unstable thoracolumbar burst fractures.

The Predictive Value of the Load Sharing Classification Concerning Sagittal Collapse and Posterior Instrumentation Failure: A Systematic Literature Review

STUDY DESIGN

Systematic review.

OBJECTIVE

In 1994, the Load Sharing Classification (LSC) was introduced to aid the choice of surgical treatment of thoracolumbar spine fractures. Since that time this classification system has been commonly used in the field of spine surgery. However, current literature varies regarding its use and predictive value in relation to implant failure and sagittal collapse. The objective of this study is to assess the predictive value of the LSC concerning the need for anterior stabilization to prevent sagittal collapse and posterior instrumentation failure.

METHODS

An electronic search of PubMed, Medline, Embase, and the Cochrane Library was performed. Inclusion criteria were (1) cohort or clinical trial (2) including patients with thoracolumbar burst fractures (3) whose severity of the fractured vertebrae was assessed by the LSC.

RESULTS

Five thousand eighty-two articles have been identified, of which 21 articles were included for this review. Twelve studies reported no correlation between the LSC and sagittal collapse or instrumentation failure in patients treated with short-segment posterior instrumentation (SSPI). Seven articles found no significant relation; 5 articles found no instrumentation failure at all. The remaining 9 articles experienced failure in patients with a high LSC or recommended a different surgical technique.

CONCLUSIONS

Although the LSC was originally developed to predict the need for anterior stabilization in addition to SSPI, many studies show that SSPI only can be sufficient in treating thoracolumbar fractures regardless of the LSC. The LSC might have lost its value in predicting sagittal collapse and posterior instrumentation failure.

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

Background

Monsegmental 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.

Methods

This 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.

Results

No 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).

Conclusions

MSPI 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.

Posterior Cruciate Ligament Tibial Avulsion treated with Open Reduction and Internal Fixation

The optimal treatment for thoracolumbar fractures (TLF) without neurological deficit remains controversial. Majority of the systematic reviews and meta-analyses have evaluated open operative approaches but have yet to compare the outcomes of minimally invasive percutaneous pedicle fixation (MIPPF) versus non-operative treatment. A retrospective cohort study was performed to compare clinical and radiological outcomes between MIPPF and conservative groups for TLF AO Type A1 to Type B2 during a 2-year follow-up period. Pre-operative plain and CT films were evaluated and decision made for short segment (non-fusion) MIPPF. Patients who refused operation were treated conservatively with three months of body cast, brace, or corset. MIPPF group showed earlier Visual Analog Score(VAS) improvement at six months post-injury (0 vs 6.0- p<0.001), as well as better functional and radiological outcomes (p<0.050) at final follow-up. Progressions of regional kyphosis (RK) were noted in both groups but there was no significant difference within and between them(p>0.050). MIPPF as a method of internal bracing can be pursued in the treatment of TLF, with larger future cohorts and RCTs being called for to support and explore new findings.

Minimally invasive spine surgery in the treatment of thoracolumbar and lumbar spine trauma

Thoracolumbar and lumbar trauma account for the majority of traumatic spinal injuries. The mainstay of current treatments is still nonoperative therapy with bracing. Classic treatment algorithms reserved absolute surgical intervention for spinal trauma patients with neurological compromise or instability. Relative indications included incapacitating pain and obesity/body habitus making brace therapy ineffective. In the past decade, minimally invasive surgical (MIS) techniques for spine surgery have been increasingly used for degenerative conditions. These same minimally invasive techniques have seen increased use in trauma patients. The goal of minimally invasive surgery is to decrease surgical morbidity through decreased soft-tissue dissection while providing the same structural stability afforded by classic open techniques. These minimally invasive techniques involve percutaneous posterior pedicle fixation, vertebral body augmentation, and utilization of endoscopic and thoracoscopic techniques. While MIS techniques are somewhat in their infancy, an increasing number of studies are reporting good clinical and radiographic outcomes with these MIS techniques. However, the literature is still lacking high-quality evidence comparing these newer techniques to classic open treatments. This article reviews the relevant literature regarding minimally invasive spine surgery in the treatment of thoracolumbar and lumbar trauma.

Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures

BACKGROUND CONTEXT

Traditional 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.

PURPOSE

To study the clinical, functional, and radiologic results of PFFV for severe, unstable thoracolumbar injuries (LSC≥7) at a minimum of 2 years.

STUDY DESIGN

A retrospective review of case records.

PATIENT SAMPLE

Thirty-two patients with an unstable burst fracture of LSC≥7 treated with PFFV were included.

OUTCOME MEASURES

They 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.

METHODS

Thirty-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.

RESULTS

None 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.

CONCLUSIONS

Reduction 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.

Does the load-sharing classification predict ligamentous injury, neurological injury, and the need for surgery in patients with thoracolumbar burst fractures?: Clinical article

OBJECT

The load-sharing score (LSS) of vertebral body comminution is predictive of results after short-segment posterior instrumentation of thoracolumbar burst fractures. Some authors have posited that an LSS > 6 is predictive of neurological injury, ligamentous injury, and the need for surgical intervention. However, the authors of the present study hypothesized that the LSS does not predict ligamentous or neurological injury.

METHODS

The prospectively collected spinal cord injury database from a single institution was queried for thoracolumbar burst fractures. Study inclusion criteria were acute (< 24 hours) burst fractures between T-10 and L-2 with preoperative CT and MRI. Flexion-distraction injuries and pathological fractures were excluded. Four experienced spine surgeons determined the LSS and posterior ligamentous complex (PLC) integrity. Neurological status was assessed from a review of the medical records.

RESULTS

Forty-four patients were included in the study. There were 4 patients for whom all observers assigned an LSS > 6, recommending operative treatment. Eleven patients had LSSs ≤ 6 across all observers, suggesting that nonoperative treatment would be appropriate. There was moderate interobserver agreement (0.43) for the overall LSS and fair agreement (0.24) for an LSS > 6. Correlations between the LSS and the PLC score averaged 0.18 across all observers (range -0.02 to 0.34, p value range 0.02-0.89). Correlations between the LSS and the American Spinal Injury Association motor score averaged -0.12 across all observers (range -0.25 to -0.03, p value range 0.1-0.87). Correlations describing the relationship between an LSS > 6 and the treating physician's decision to operate averaged 0.17 across all observers (range 0.11-0.24, p value range 0.12-0.47).

CONCLUSIONS

The LSS does not uniformly correlate with the PLC injury, neurological status, or empirical clinical decision making. The LSSs of only one observer correlated significantly with PLC injury. There were no significant correlations between the LSS as determined by any observer and neurological status or clinical decision making.

Nonoperative versus operative treatment for thoracolumbar burst fractures without neurologic deficit: a meta-analysis

BACKGROUND

Decision-making regarding nonoperative versus operative treatment of patients with thoracolumbar burst fractures in the absence of neurologic deficits is controversial. Lack of evidence-based practice may result in patients being treated inappropriately and being exposed to unnecessary adverse consequences.

PURPOSE

Using meta-analysis, we therefore compared pain (VAS) and function (Roland Morris Disability Questionnaire) in patients with thoracolumbar burst fractures without neurologic deficit treated nonoperatively and operatively. Secondary outcomes included return to work, radiographic progression of kyphosis, radiographic progression of spinal canal stenosis, complications, cost, and length of hospitalization.

METHODS

We searched MEDLINE, EMBASE(®), and the Cochrane Central Register of Controlled Trials for 'thoracic fractures', 'lumbar fractures', 'non-operative', 'operative' and 'controlled clinical trials'. We established five criteria for inclusion. Data extraction and quality assessment were in accordance with Cochrane Collaboration guidelines. The main analyses were performed on individual patient data from randomized controlled trials. Sensitivity analyses were performed on VAS pain, Roland Morris Disability Questionnaire score, kyphosis, and return to work, including data from nonrandomized controlled trials and using fixed effects meta-analysis. We identified four trials, including two randomized controlled trials consisting of 79 patients (41 with operative treatment and 38 with nonoperative treatment). The mean followups ranged from 24 to 118 months.

RESULTS

We found no between-group differences in baseline pain, kyphosis, and Roland Morris Disability Questionnaire scores. At last followup, there were no between-group differences in pain, Roland Morris Disability Questionnaire scores, and return to work rates. We found an improvement in kyphosis ranging from means of 12.8º to 11º in the operative group, but surgery was associated with higher complication rates and costs.

CONCLUSIONS

Operative management of thoracolumbar burst fractures without neurologic deficit may improve residual kyphosis, but does not appear to improve pain or function at an average of 4 years after injury and is associated with higher complication rates and costs.

LEVEL OF EVIDENCE

Level II, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.

Tratamento conservador da fratura toracolombar explosão e Classificação de McComack

OBJETIVO: Correlacionar a classificação de McCormack e o resultado funcional nos portadores de fratura toracolombar explosão tratados com gesso em hiper-extensão ou ortese toracolombossacra. MÉTODOS: Análise retrospectiva de prontuários, radiografias e de tomografia de 31 pacientes no período de 1996 a 2005. O resultado funcional ao final do tratamento obtido mediante as escalas funcionais de dor e trabalho de Denis. RESULTADOS: Dos 31 pacientes avaliados, cinco apresentavam incapacidade total ou parcial para retorno ao trabalho ao final do período de segmento; 26 (83,9 %) estavam aptos ao trabalho com ou sem mudança da atividade trabalhista. Em relação à dor (r=0,258;p=0,161) e função (r=0,204;p=0,272), não houve correlação entre a pontuação da classificação e a função no final do acompanhamento. CONCLUSÃO: Considerando critérios funcionais centrados nos pacientes, não observamos correlação entre a Classificação de McCormack e os resultados do tratamento conservador. Nivel de Evidência IV, série de casos.

Estudio comparativo del tratamiento ortésico en las fracturas toraco-lumbosacras según la gravedad del trauma

OBJETIVO: Determinar si la gravedad del trauma en lesiones toracolumbosacras mayores estables permite decidir la selección del tipo de ortesis en un tratamiento ortopédico. MÉTODOS: Estudio Retrospectivo de casos 12/1990 - 12/2006 (16 años). Criterios de Selección: 1) Seguimiento mínimo: 2 años. 2) Estudios radiológicos convencionales completos. 3) Ausencia de Litigio. 4) Tratamiento ortésico con TLSO a medida para los traumas de alta energía cinética y con ortesis prefabricadas para los de baja energía. 5) Tratamiento efectuado o supervisado por el autor Sénior. Evaluación por observadores independientes de Parámetros Geométricos (ángulo de Cobb sagital, cifosis vertebral, grado de colapso vertebral) pretratamiento y seguimiento en Rx simple, y Parámetros Funcionales (Dolor según SRS, Índice de Oswestry, Retorno a la Actividad Previa). Subdivisión de los diferentes tipos de fracturas (según AO y Denis) en Alta (Grupo A) y Baja Energía [Grupo B] de acuerdo con la energía cinética del trauma. Comparación de Parámetros Geométricos con Grupo Control. Análisis Estadístico: chi cuadrado y t-test de Student. RESULTADOS: 41 pacientes (44 fracturas] tratados (23 mujeres/18 varones), con 25 fracturas Grupo "A", y 19 Grupo "B". Edad promedio: 46 años (12 - 83). Seguimiento promedio: 4,5 años (2.2 - 15.5). Localización predominante: T11 - L2. Tipos Predominantes: tipo A (AO) o por compresión y por estallido. No hubo diferencias significativas en las mediciones efectuadas en cada grupo pretratamiento y al seguimiento. La única diferencia significativa entre grupos fue en la cifosis vertebral inicial tanto en general como según la clasificación AO entre los tipos A de alta y baja energía. La comparación al seguimiento de los parámetros geométricos entre grupo control y grupos A y B así como entre grupo control y cada tipo (AO/Denis) subdivididos en alta o baja energía, arrojó siempre diferencias significativas. Los parámetros funcionales al seguimiento mostraron siempre puntuaciones promedio buenas, con variaciones significativas entre grupos A y B. El retorno a la actividad previa fue del 90,6%, sin diferencias entre trabajadores de esfuerzo físico y de escritorio. CONCLUSIONES: Es posible lograr un Resultado Clínico Funcional satisfactorio a mediano plazo en las lesiones toracolumbosacras mayores estables seleccionando el tipo de ortesis según que el trauma sea de alta o baja energía cinética. Los resultados clínicos funcionales parecen ser mejores en los casos de Trauma de Alta Energía. Sin embargo, este tratamiento no mejora ni empeora los parámetros radiológicos sagitales.

Clasificación de las fracturas toracolumbares: comparación entre las clasificaciones de AO y Vaccaro

OBJETIVO: as classificações têm mudado na último metade do século, sendo a mais usada desde a última década, a classificação AO. Em 2004, Vaccaro et al. propuseram a Thoraco-Lumbar Injury Classification (TLICS). MÉTODOS: análise da reprodução inter e intraobservador, utilizando o teste Kappa das classificações entre três níveis distintos de traumatólogos em formação, em 30 casos. RESULTADOS: a reprodução intraobservador na classificação de Vaccaro foi: OI: 0,73; OII: 0,6 e OIII: 0,63. Para a classificação AO, 0,77; 0,7 e 0,6, respectivamente. Entre as duas classificações: OI: 0,59; OII: 0,7 e OIII: 0,62. A avaliação interobservador para a classificação de Vaccaro foi de 0,66 e para a classificação AO de 0,67. Os pontos críticos foram rotação e lesões do complexo ligamentar posterior. CONCLUSÕES: as duas classificações mostram um bom grau de concordância (índice Kappa). Com a de Vaccaro, observou-se concordância global de 69%. Com respeito à indicação do tratamento ortopédico, a concordância foi de 37%. A indicação de tratamento cirúrgico foi de 29%. Cabe salientar que essa classificação dispõe de um nível impreciso em que pode-se optar por qualquer dos dois tratamentos (TLICS 4), o qual foi observado em 3%. Não houve concordância em 31%. As mesmas indicações para a classificação AO apresentaram concordância global de 67%. Indicação ortopédica foi de 32%. Foi realizada uma cirurgia em 21%. Nas lesões classificadas como A3 (14%), a sua indicação de tratamento não foi definida com unanimidade entre os observadores.

Combined anterior-posterior surgery versus posterior surgery for thoracolumbar burst fractures: a systematic review of the literature

STUDY DESIGN

A systematic quantitative review of the literature.

OBJECTIVE

To compare combined anterior-posterior surgery versus posterior surgery for thoracolumbar fractures in order to identify better treatments.

SUMMARY OF BACKGROUND DATA

Axial load of the anterior and middle column of the spine can lead to a burst fracture in the vertebral body. The management of thoracolumbar burst fractures remains controversial. The goals of operative treatment are fracture reduction, fixation and decompressing the neural canal. For this, different operative methods are developed, for instance, the posterior and the combined anterior-posterior approach. Recent systematic qualitative reviews comparing these methods are lacking.

METHODS

We conducted an electronic search of MEDLINE, EMBASE, LILACS and the Cochrane Central Register for Controlled Trials.

RESULTS

Five observational comparative studies and no randomized clinical trials comparing the combined anteriorposterior approach with the posterior approach were retrieved. The total enrollment of patients in these studies was 755 patients. The results were expressed as relative risk (RR) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes with 95% confidence intervals (CI).

CONCLUSIONS

A small significantly higher kyphotic correction and improvement of vertebral height (sagittal index) observed for the combined anterior-posterior group is cancelled out by more blood loss, longer operation time, longer hospital stay, higher costs and a possible higher intra- and postoperative complication rate requiring re-operation and the possibility of a worsened Hannover spine score. The surgeons' choices regarding the operative approach are biased: worse cases tended to undergo the combined anterior-posterior approach.

Anterior-only stabilization using plating with bone structural autograft versus titanium mesh cages for two- or three-column thoracolumbar burst fractures: a prospective randomized study

STUDY DESIGN

A randomized, controlled follow-up study to review patients with acute thoracolumbar burst fractures treated by anterior instrumentation and reconstruction.

OBJECTIVE

The objective of this study was to evaluate the results of anterior instrumentation in the treatment of thoracolumbar burst fractures and to determine whether anterior-only approach would be sufficient for highly unstable burst fractures. In this prospective follow-up study, we also compared the results of anterior reconstruction with structural grafting and with titanium mesh cage in a randomized fashion.

SUMMARY OF BACKGROUND DATA

Anterior decompression and reconstruction supplemented with instrumentation is generally believed to be superior to fixation with posterior pedicle screw instrumentation for a highly unstable burst fracture, but the indications and methods for anterior approach has not been fully documented.

METHODS

A total of 65 patients undergoing anterior plating for a thoracolumbar burst fracture with a load-sharing score of 7 or more between 2000 and 2003 were included this study. They were randomized to receive iliac crest autograft (group A, n = 32) or titanium mesh cages (group B, n = 33). The patients were similar in the distribution of 3-column injuries (n = 8 in group A vs. n = 9 in group B). During the minimum 4-year (range, 4-7 years) follow-up period, all patients were prospectively evaluated for clinical and radiologic outcomes. The Frankel scale, the ASIA motor score, and the Short Form 36 were used for clinical evaluation, whereas the fusion status and the loss of kyphosis correction for the local kyphosis angle were examined for radiologic outcome.

RESULTS

All patients in this study achieved solid fusion, with significant neurologic improvement and no significant correction loss as defined by loss of kyphosis correction. The clinical and radiologic results were not significantly different (P > 0.05) at all time points between the 2 groups A and B. Twenty-six of 32 patients in group A still complained of donor site pain to some degree at the final follow-up. No significant impact of 3-column injuries (P > 0.05) were identified on the results for all comparisons.

CONCLUSION

Anterior-only instrumentation and reconstruction with structural autograft or titanium mesh cages is sufficient for surgical treatment of thoracolumbar burst fractures with a load-sharing score of > or = 7 and even with 3-column injuries.

Posterior short-segment fixation with or without fusion for thoracolumbar burst fractures. a five to seven-year prospective randomized study

BACKGROUND

The impact of fusion as a supplement to short-segment instrumentation for the treatment of thoracolumbar burst fractures is unclear. We conducted a controlled clinical trial to define the effect of fusion on lumbar spine and patient-related functional outcomes.

METHODS

From 2000 to 2002, seventy-three consecutive patients with a single-level Denis type-B burst fracture involving the thoracolumbar spine and a load-sharing score of <or=6 were managed with posterior pedicle screw instrumentation. The patients were randomly assigned to treatment with posterolateral fusion (fusion group, n = 37) or without posterolateral fusion (nonfusion group, n = 36). The patients were followed for at least five years after surgery and were assessed with regard to clinical and radiographic outcomes. Clinical outcomes were evaluated with use of the Frankel scale, the motor score of the American Spinal Injury Association, a visual analog scale, and the Short Form-36 (SF-36) questionnaire. Radiographic outcomes were assessed on the basis of the local kyphosis angle and loss of kyphosis correction.

RESULTS

No significant difference in radiographic or clinical outcomes was noted between the patients managed with the two techniques. Both operative time and blood loss were significantly less in the nonfusion group compared with the fusion group (p < 0.05). Twenty-five of the thirty-seven patients in the fusion group still had some degree of donor-site pain at the time of the latest examination.

CONCLUSIONS

Posterolateral bone-grafting is not necessary when a Denis type-B thoracolumbar burst fracture associated with a load-sharing score of <or=6 is treated with short-segment pedicle screw fixation.

The load-sharing classification of thoracolumbar fractures: an in vitro biomechanical validation

STUDY DESIGN

An in vitro biomechanical investigation.

OBJECTIVES

The purpose of this study was to investigate the association between various load-sharing score and the acute flexibility of thoracolumbar fractures by measuring the 3-dimensional flexibility data.

SUMMARY OF BACKGROUND DATA

The load-sharing classification is a way to describe the injury severity of a spinal fracture and can be very useful in determining successful candidates for the choice of operative approaches. However, this classification needs to be validated by biomechanical and more clinical studies before its widespread use. To date, no biomechanical study was available.

METHODS

Eighteen fresh bovine T12-L3 specimens were harvested and divided into 3 groups, and subjected to axial compressive impact with 63.8, 107.8, and 137.2 J energy, respectively. Radiograph films and computed tomography scans of the experimental spine were taken in neutral posture after trauma. Multidirectional flexibility of each specimen was measured under flexion-extension, right/left lateral bending, and right/left axial rotation before and after trauma. The association between the multidirectional instabilities and the vertebral injuries to each of load-sharing point score was analyzed.

RESULTS

The load-sharing score of a fracture increased with the level of impact energy. Significant positive correlations were found between the load-sharing score and the motion parameters (average R = 0.434, average P = 0.004). Fractures with mild comminution (< or =6 points) showed more stability as compared to those with more comminution (> or =7 points) (P < or = 0.016).

CONCLUSION

This study confirms that assessing the load-sharing score should be helpful in evaluating the acute instability of thoracolumbar fractures, and justifies the use of load-sharing classification in the thoracolumbar fractures.

Treatment of unstable thoracolumbar junction burst fractures with short- or long-segment posterior fixation in magerl type a fractures

The treatment of thoracolumbar fractures remains controversial. A review of the literature showed that short-segment posterior fixation (SSPF) alone led to a high incidence of implant failure and correction loss. The aim of this retrospective study was to compare the outcomes of the SS- and long-segment posterior fixation (LSPF) in unstable thoracolumbar junction burst fractures (T12-L2) in Magerl Type A fractures. The patients were divided into two groups according to the number of instrumented levels. Group I included 32 patients treated by SSPF (four screws: one level above and below the fracture), and Group II included 31 patients treated by LSPF (eight screws: two levels above and below the fracture). Clinical outcomes and radiological parameters (sagittal index, SI; and canal compromise, CC) were compared according to demographic features, localizations, load-sharing classification (LSC) and Magerl subgroups, statistically. The fractures with more than 10 degrees correction loss at sagittal plane were analyzed in each group. The groups were similar with regard to age, gender, LSC, SI, and CC preoperatively. The mean follow-ups were similar for both groups, 36 and 33 months, respectively. In Group II, the correction values of SI, and CC were more significant than in Group I. More than 10 degrees correction loss occurred in six of the 32 fractures in Group I and in two of the 31 patients in Group II. SSPF was found inadequate in patients with high load sharing scores. Although radiological outcomes (SI and CC remodeling) were better in Group II for all fracture types and localizations, the clinical outcomes (according to Denis functional scores) were similar except Magerl type A33 fractures. We recommend that, especially in patients, who need more mobility, with LSC point 7 or less with Magerl Type A31 and A32 fractures (LSC point 6 or less in Magerl Type A3.3) without neurological deficit, SSPF achieves adequate fixation, without implant failure and correction loss. In Magerl Type A33 fractures with LSC point 7 or more (LSC points 8-9 in Magerl Type A31 and A32) without severe neurologic deficit, LSPF is more beneficial.

Classificação de McCormack e colapso sagital na fratura toracolombar explosão

O aumento da cifose toracolombar após tratamento conservador da fratura tipo explosão é complicação constatada por vários autores. Realizamos estudo retrospectivo com 33 portadores de fratura toracolombar do tipo explosão submetidos ao tratamento conservador entre 1992 a 2004 para verificar a correlação entre a cifose toracolombar e a Classificação de McCormack, que pontua a gravidade da fratura conforme a cominuição do corpo, o deslocamento dos fragmentos no corpo vertebral e a quantidade de correção da deformidade em cifose após o tratamento. Após 30 meses de seguimento médio, verificamos correlação entre a pontuação da Classificação de McCormack, conhecida na literatura como load sharing classification, e o colapso vertebral sagital nestes pacientes (p<0,05;r=0,65). A despeito de ser descrita para avaliação do colapso sagital após o tratamento cirúrgico, a aplicabilidade desta Classificação pode ser considerada para os portadores de fratura toracolombar explosão submetidos ao tratamento conservador.

Classification-related approach in the surgical treatment of thoracolumbar fractures

BACKGROUND

Advanced diagnostic tools, classification systems and accordingly selected surgical approaches are essential requirements for the prevention of failure of surgical treatment of thoracolumbar fractures. The present study is designed to evaluate the contribution of classification to the choice of a surgical approach using the current fracture classification systems.

MATERIALS AND METHODS

We studied prospectively a group of 64 patients (22 females, 42 males) of an average age of 43 years, all operated on for thoracolumbar fractures during the year 2001. The AO-ASIF classification was used preoperatively with all imaging studies (X-ray, computed tomography (CT) and magnetic resonance imaging (MRI)). When the damage was detected only in the anterior column (A type), an isolated anterior stabilization (n = 22) was preferred. If the MRI study disclosed an injury in the posterior column, a posterior approach (n = 20) using the internal fixator was chosen. Injuries involving the posterior column (B or C type) were classified additionally according to the load-sharing classification (LSC). If LSC gave six or more points, treatment was completed with an anterior fusion. The combined postero-anterior procedure was carried out 22 times. The minimum followup period was 22 months.

RESULTS

Neither implant failure and nor significant loss of correction were observed in patients treated with anterior or combined procedures. The average loss of correction (increase of kyphosis) in simple posterior stabilization was 3.1 degree.

CONCLUSION

Complex fracture classification helps in the selection of the surgical approach and helps to decrease the chances of treatment failure.

Validating a newly proposed classification system for thoracolumbar spine trauma: looking to the future of the thoracolumbar injury classification and severity score

BACKGROUND

Although numerous systems have been proposed, there is no universally accepted classification or scoring system for thoracolumbar spine injuries. Some have gained popularity, but most systems have never been modified or advanced beyond their initial introductory state. To the authors' knowledge, no thoracolumbar classification system has ever been validated in a systematic and scientific manner.

STUDY PURPOSE

To critically review previous thoracolumbar classification systems, to discuss the proposal of the new Thoracolumbar Injury Classification and Severity Score (TLICS), to review the steps taken thus far in assessing the reliability of this system, and to discuss plans for future clinical validation of TLICS.

METHODS

The authors performed a comprehensive search and analysis of previously published systems for classifying or scoring thoracolumbar spine injuries. Based on the merits and faults of these systems, among other factors, they have developed TLICS.

CONCLUSIONS

Of the three phases of validating a fracture classification system described by Audige et al, TLICS has successfully passed through phase 1 (development) and phase 2 (multicenter agreement studies). With modifications made in response to phase 2 studies, TLICS will be ready to enter into the clinical validation phase. Although TLICS will initially be assessed for its ability to predict type of treatment, it is the authors' hope that, with appropriate analysis, the system will also be predictive of injury severity and clinical outcomes. These qualities remain to be demonstrated through rigorous prospective clinical investigation.

Traumatic noncontiguous double fracture-dislocation of the lumbosacral spine

BACKGROUND CONTEXT

To our knowledge, the presence of noncontiguous fracture-dislocation of the lumbosacral spine occurring at two levels has not been reported. The etiology, evaluation, and treatment of the unusual injury is presented.

PURPOSE

To notify spinal traumatologists about the possibility of this unusual injury.

STUDY DESIGN

A case report of an unusual noncontiguous double fracture-dislocation of the lumbosacral spine.

METHODS

A 26-year-old man was involved in a motor vehicle accident where his car fell over a bridge and plummeted approximately 300 feet before hitting the ground. The patient was transported to a major medical center where he was found to be conscious, and amazingly, his only major injury was fracture-dislocations of L2-L3 and L5-S1. His preoperative neurologic status showed a partial paraparesis to all motor groups of the lower extremities bilaterally.

RESULTS

The patient underwent a posterior reduction, instrumentation, and fusion from L1 to S1 with autogenous bone graft and segmental pedicle screw instrumentation. One week postoperatively, he underwent an anterior spinal fusion of L5/S1. Postoperatively, his neurologic status improved allowing him to be ambulatory, with a normal lumbosacral alignment being well-maintained.

CONCLUSIONS

Noncontiguous double fracture-dislocation of the lumbosacral spine is an unusual injury, which results from a very high-energy trauma. Prompt recognition of the injuries, reduction of the fracture-dislocations, and posterior stabilization is recommended for neural decompression, spinal alignment, and long-term stabilization.

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.