Purpose: To determine whether neural axis level of injury (SCI, CMI, or CEI) is related to motor improvement, as defined by the International Standards for Neurological Classification of Spinal Cord Injury motor score (MS), in patients with a thoracolumbar (T11-L3) spine injury.

Method: Fifty-three patients who sustained a neurological deficit secondary to a thoracolumbar spinal injury between 1995–2003 had injury details and MS collected prospectively. An independent evaluation determined the follow-up MS and SF-36 generic health-related quality of life (HrQOL) at a mean of 6.6 (SD 2.5) years post-injury. All patients had an MRI reviewed by a spine surgeon and neuroradiologist to determine the location of their conus medullaris and precise level of neural axis injury.

Results: Nineteen patients (37%) had SCI, 20 (39%) had CMI, and 12 (24%) had CEI, while two could not be classified. Patients with SCI improved their MS by an average 7.0 motor points (SD 9.8); CMI improved 11.9 (SD 11.8); and CEI improved 16.8 (SD 16.0). This trend did not achieve statistical significance (p=0.09). Multivariate analyses demonstrated that initial MS had a significant interaction with neural axis level of injury with respect to the primary outcome. Specifically, CEI showed the greatest improvement in MS only when the initial MS was less than 75. Absence of initial anal sensation, a fracture-dislocation injury type and increasing time to surgery were all statistically associated with less improvement in MS. The mean follow-up SF-36 physical component score (PCS) was 37.3 (SD 10.1) and the mean mental component score (MCS) was 51.4 (SD 11.8). There was no significant difference in mean PCS and MCS for varying levels of neural axis injury.

Conclusion: Patients with a CEI demonstrated the most improvement in MS, while absent anal sensation, a fracture-dislocation, and long delay to surgery were poor prognostic indicators for motor recovery. The HrQOL outcomes did not vary with neural axis level of injury. The results of this study assist in determining a prognosis for patients that sustain these common injuries. Future research should focus on how specific pre- and peri-operative variables affect outcomes in patients with neurological deficits secondary to thoracolumbar injuries.

The Dynesys is a flexible posterior stabilization system that is designed to preserve intersegmental kinematics and reduce loading at the facet joints. The purpose of this study was to determine if the length of the Dynesys spacer has an effect on range of motion (ROM) at the implanted level. Spacer length was found to significantly affect ROM in all three loading directions with and without a follower preload. The longer spacer increased ROM and the shorter spacer decreased ROM, largely due to differences in segmental compression between the two.

The Dynesys, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve intersegmental kinematics and alleviate loading at the facet joints. Recent biomechanical evidence suggests that motion with Dynesys is less than the intact spine (Schmoelz, 2003). The purpose of this investigation was to determine if the length of the Dynesys spacer contributes to differences in range of motion (ROM) at the implanted level.

Ten cadaveric lumbar spine segments (L2-L5) were tested by applying a pure moment of ±7.5Nm in three directions of loading with and without a follower preload of 600N. Test conditions included: intact, injury at L3-L4, Dynesys at L3-L4 (standard spacer), long spacer (+2mm), and short spacer (−2mm). Intervertebral rotations were measured using an optoelectronic camera. Pressure sensors placed inside the joint capsules measured facet loads. Statistical significance was determined using repeated measures ANOVA.

Spacer length had a significant effect on ROM in all three loading directions with and without a follower preload. Initial contact loads within the facet joints were 150% and 64% that of the standard spacer for the short and long spacer, respectively.

The magnitude of distraction of the segment affects ROM. Shorter spacers increased segmental compression of the intervertebral disc and facet joints and therefore reduced ROM. With a follower preload, the segment is further compressed and ROM is further reduced.

The results contribute to an understanding of the design of such implants and could help guide future research.

Funding: Synos Foundation, Switzerland, National Science and Engineering Research Council of Canada (NSERC)

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Introduction: Reported standardized functional outcome assessment of flexion distraction injuries of the thoracolumbar spinal column seems to be lacking in the literature. The primary focus of this study was the long term functional outcome in this patient population in view of the management employed in a tertiary spine referral center. In an attempt to overcome the lack of pre-injury Health Related Quality of Life (HRQOL) data, patient recall of the pre-injury state was used.

Secondary outcomes included the long-term disease-specific HRQOL in these patients, the correlation between radiographic alignment and functional outcome, comparison of HRQOL between operative and non-operative care, and identifying potential prognostic factors influencing functional HRQOL.

Method: A database generated retrospective cohort study with a cross-sectional outcome analysis was carried out for patients with a thoracolumbar (T11-L2) flexion-distraction injury treated at a tertiary care referral center between 1995 and 2000.

Inclusion criteria were age over sixteen, and referral to our center for a traumatic thoracolumbar flexion-distraction injury within two weeks of the injury. Exclusion criteria were an associated spinal cord injury, a previous spine injury or a multi-level spine injury, a significant associated other system injury with an ISS > 50, or patient refusal or inability to complete the outcome questionnaires. Patients were followed for a minimum of two years. Injury classification, healing, and alignment were determined by radiographic analysis. Standing lateral x-rays at final follow-up were used to determine the amount of residual kyphosis by two independent observers.

Results: A total of 87 patients were identified by the research database, of which 83 met inclusion and exclusion criteria. Twenty-eight patients were lost to follow-up, leaving 55 eligible patients. Eight refused to participate. Of the 47 remaining patients, 40 completed questionnaires representing a response rate of 85%.

There were 26 males and 14 females with a mean age of 27.4 years (range 16–48). Average follow-up was 3.3 years (range 2.5–7). Twenty-five patients (64.9%) were treated operatively and fifteen patients (35.1%) underwent non-operative management. Complications in the surgical group included one non-union, three cases of painful instrumentation, and one infection. In the non-surgical group, two patients developed non-unions requiring surgical intervention.

Comparing the follow-up mean SF-36 PCS and MCS scores to the recalled baseline SF-36 pre-injury scores, demonstrated the patients did not return to baseline physical component and mental component scores (p < 0.001).

The mental component (MCS) and NASS pain scores showed significant statistical difference between the two groups with a trend of non-surgical patients scoring higher.

There was no statistically significant difference in the SF-36 PCS between the two groups.

Linear and multiple regression models identified “associated other system injuries” as the only useful predictor of outcome influencing the SF-36 PCS. Patients with associated injuries are likely to have a poorer prognosis with lower scores.

Radiographically, there was no association between degree of kyphosis at last follow-up and outcome.

Discussion: Long term functional outcome assessment in this patient population and comparison between the surgical and non-surgical groups, revealed a trend in the non-surgical group towards reporting higher scores on both the generic and disease-specific questionnaires. There were also a higher number of complications associated with the surgical group, as well as potential residual back pain related to instrumentation.

Limitations of the study were the retrospective nature of the study, as well as the inherent absence of real time pre-injury quality of life assessment. The study is, however, strengthened by a homogeneous cohort and the use of validated outcome measures. It also involves a cross-sectional analysis and so has a prospective component

Conclusion: The health related quality of life in patients treated for flexion-distraction injuries without spinal cord injury is favorable overall, but does not return to normal after an average of two years following injury, with a trend in the non-surgical group towards reporting higher scores on both the generic and disease-specific questionnaires. Radiographically, no association was found between degrees of focal kyphosis at last follow-up and functional outcome.

Introduction: There is clear evidence that violating the margins of a sarcoma or other malignancy during surgical resection will risk local recurrence and diminish overall survival. Previous publications have retrospectively demonstrated this oncologically sound approach to spine tumor management to be internally valid. The external validity or limited generalizability has not been assessed.

Methods: A prospective cohort study design. Included were all patients who underwent enbloc surgical resection of a primary tumor of the spine between January 1994 and November 2003, at the authors’ institution. Tumors were classified using the Ennking and WBB staging systems. All specimens were submitted to a single experienced musculoskeletal pathologist. Surgery was performed by the authors. Surgical approach, specimen margins, complications, adjuvant therapy, neurological status, local recurrence and survival were prospectively collected.

Results: Twenty-six patients (12 males and 14 females) were eligible for the study. Average age was 42 (range 16 to 70). There were 19 malignant tumors and 7 benign. Review by the pathologist revealed that 13 resections were wide, 5 marginal (at dura) and 7 intralesional (2 planned wide, 1 planned marginal). Except in benign lesions intral-esional or marginal margins occurred at dura.

There are 20 surviving patients with an average follow up of 41.5 months (range 6 to 111 months), 15 of who had malignant tumors. None of these patients have evidence of local recurrence and one has evidence of systemic disease.

The health related quality of life, using the SF-36, shows acceptable morbidity of these procedures (PCS=37.73 ± 11.52, MCS=51.69 ± 9.54).

Conclusions: Principles of wide surgical resection, commonly applied in appendicular oncology, can and should be used for the treatment of primary bone tumors of the spine with anticipated acceptable morbidity and satisfactory survival.