To analyse the pain distribution in the acute and chronic phase following thoracolumbar fractures.

Prospective observational study

39 patients with fractures between T11 and L2, with no neurological deficit, were treated conservatively. Strict inclusion and exclusion criteria were applied. All had X-rays and MR imaging (whole spine) at post-injury and one-year follow-up.

The patients documented their pain distribution using pain drawing, along with 10 other domains of pain and functional outcomes for a period over 12 months. The pain distribution was analysed. The association of distal pain distribution to - other associated injury, resultant kyphosis, Pre-existing or increase in disc degeneration at the lower non-injured disc levels – were analysed and reviewed

The most common site of the pain distribution in both the acute (90%) and chronic phase (97%) was distal to the fracture (regions - iliac crest, lumbosacral junction and buttock). Factors mentioned above that could be related to distal pain distribution did not show any significant correlation (P>0.5) with different domains of pain outcome.

Some of the commonly believed reasons for distal pain distribution like resultant kyphosis and associated disc/facet pathologies were not supported by our study findings. The distal pain distribution corresponds to the scelerotomal referred pain mapping, which could be the probable explanation. Thoracolumbar pathologies could be the source of pain in patients complaining of low back symptoms. Distal pain distribution of spine pathologies should not be attributed as functional.

Stable thoracolumbar fracture is a common injury. The factors that determine its outcome are unclear. Aspects of injury severity were analysed for their ability to predict outcome by controlling other outcome-affecting factors (patient's pre-injury health status, legal aspects, associated injuries, etc.). No reliable disc injury severity grading system was available and therefore a new system was developed.

A prospective observational study of 44 conservatively treated patients with stable fractures between T11 and L5 was conducted. Bony injury severity was scored based on comminution, apposition and kyphosis parameters. Disc injury severity was scored by the new scale based on variables – Herniation, Indentation, Height decrease and Signal change – seen in MRI. Ten outcome domains (five domains of pain and function each) were assessed at 1 to 2 years from injury. The data was analysed by non-parametric correlation and stepwise-linear regression analysis to assess the predictive value of different variables (patient factors, injury factors and social factor) to outcome.

The correlation coefficients between injury severity and outcome were consistently higher with disc injury severity than bony. Disc injury severity showed highest predictive value for both pain (29%) and functional (16%) outcomes, whereas the bony injury severity parameters (kyphosis, etc.) and the posterior ligament injury severity provided no prediction of outcome. According to AO classification, the fractures were A1, A2, A3 and B1; in this spectrum of injuries, the AO classification had no prediction of outcome. The disc injury score also had a good predictive value for final disc degeneration.

Disc injury severity should be gauged in advising prognosis and treatment. The new disc injury severity grading system showed good construct validity.

Background context: Stable thoracolumbar spinal fracture is a common injury, yet there remains a relative lack of evidence that would allow reliable prediction of outcome. Variation in outcome in stable thoracolumbar spine fracture without neurological deficit could not be explained by the assessment made from x-rays and CT imaging alone, which measures mainly the bony injury severity. So far, no good classification system has been developed to assess the severity of soft tissue injury (disc).

Objectives: To measure short-term outcome of stable thoracolumbar fracture and analyse aspects of injury severity for their ability to predict outcome. To develop a new disc injury severity grading system in thoracolumbar spine fractures.

Study design: Prospective observational.

Patient sample: 44 patients with stable fractures between T11 and L5 vertebra with no neurological deficit and treated conservatively were selected.

Methods: All had plain x-rays, CT and MRI scans post-injury and at one year post-injury (except CT). Bony injury severity was scored on a seven-point ordinal scale based on (a) communication, (b) apposition and (c) kyphosis. Disc injury severity was scored by the newly developed six-point ordinal scale (none to severe) based on the following variables: (a) Herniation of the disc, (b) Indentation of the end plate, (c) Change in height and (d) Change in signal. Outcome was assessed at one to two years from injury. The following outcome measures were collected: (A) Five domains of pain symptoms – intensity, duration, bothersome, interference and satisfaction. (B) Five domains of function – Physical Component Summary (PSC) measure, Mental Component Summary (MSC) measure, Oswestry disability score, return to pre-injury level of overall activities and return to employment. Non-parametric correlation coefficients were calculated between outcome variables and other variables to look for the predictors of outcome. Stepwise linear regression analysis was performed to compare the predictive values and to look at what proportion of outcome is predicted by different predictors.

Results: According to AO classification, the fractures were A1, A2, A3 and B1. The Spearman correlation coefficients between outcome and injury severity were consistently higher with disc injury severity than bony. For the outcome of pain intensity, the correlation coefficients for disc and bone injury severity respectively were:.63 (p < .0001) and.28 (NS-not significant). Similarly for SF36 PSC were: .41 (p < .01) and.25 (NS). The predictive value of pain at F < .01 was 29% for disc injury severity and all other variable were not significant and excluded. At F < .05, the predictive value of disc injury severity (29%) increased further by 9%, 8% and 6% by addition of variable “Patient’s pre-injury SF36 MSC”, “Legal and Compensation issues pending” and “Physical demand of job” respectively. The predictive value of function at F < .01 was 16% for disc injury severity and it increased to 31% by the addition of “physical demand of the job” variable. At F < 0.05 the predictive value further increased by 5% by addition of variable “Legal and Compensation issues pending”. All other variables were not significant.

Conclusions: A new grading system of disc injury severity was developed and it showed good predictive value for pain and functional outcome. Disc injury severity has a better predictive value for short term outcome than bony injury severity in stable thoracolumbar fractures. In the spectrum of injuries studies, the AO classification and the degree of kyphosis provided no prediction of outcome.

Study Design: Prospective observational study.

Objectives: To score the severity of injury to (a) vertebrae and (b) intervertebral discs following thoraco-lumbar fracture, and compare the two in their ability to predict clinical outcome at 1–2 years.

Methods: 44 patients with fractures between T11 and L5 without neurological deficit were treated conservatively. All had plain X-rays and MRI scans immediately and at one year post-injury. Bony injury severity was scored on a seven-point ordinal scale based on a) comminution, b) apposition and c) kyphosis. Disc injury severity was scored on a six-point ordinal scale based on a) change in signal, b) change in height, c) indentation /herniation. Outcome was assessed at one to two years from injury (av. 18.1 + 5.6 months) Non-parametric correlation coefficients were calculated between injury severity variables and outcome variables.

Outcome measures: Modified Oswestry disability questionnaires, SF-36 questionnaires (physical and mental component summary scores – PCS and MCS), verbal and numeric rating scale of ability to perform pre-morbid activities/work. Detailed analysis of a.) pain (intensity, duration, character, distribution, etc.), b.) early morning stiffness (severity, frequency, and duration).

Results: According to the AO classification, 25% of the fractures were A1 (wedge), 9% were A2 (split), 45% were A3 (burst) and 20% were B1 (flexion-distraction with posterior ligament injury). Disc injuries scored as: grade 3 (mild) in 14%, grade 4 in 36%, grade 5 in 36% and grade 6 (very severe) in 14%. The spearman correlation coefficients between injury severity and outcome were consistently higher with disc injury severity than bony. For the Oswestry disability score the correlation coefficients for disc and bone injury severity respectively were 0.50 (p< .0001) and 0.40 (p< .05), for SF36-PCS: 0.43 (p< .005) and 0.32 (p< .05), for SF36-MCS: 0.43 (p< .005) and 0.06 (NS), for return to pre-morbid activities and work: 0.32 (p< .05) and 0.25 (p< .5), for pain intensity by numeric rating scale: 0.69 (p< .0001) and 0.41 (p< .01), and for pain intensity by verbal rating scale: 0.65 (p< .0001) and 0.28 (p< 0.1).

Conclusion: In all clinical outcomes assessed, there was consistently better prediction by measures of injury severity to the disc than the bone. This study offers possible explanation for previously low or conflicting evidence of correlation between clinical outcome and bony injury in thoraco-lumbar spine fractures uncomplicated by neurological injury. It implies that in selected patients with severe disc injury, treatment focused on eliminating the effects of the disc injury may result in better clinical outcome.