Aims

We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants.

The lower limbs of vehicle occupants are vulnerable to severe injuries during under vehicle explosions. Understanding the injury mechanism and causality of injury severity could aid in developing better protection. Therefore, we tested three different knee positions in standing occupants (standing, knee in hyper-extension, knee flexed at 20˚) of a simulated under‐vehicle explosion using cadaveric limbs in a traumatic blast injury simulator; the hypothesis was that occupant posture would affect injury severity.

Skeletal injuries were minimal in the cadaveric limbs with the knees flexed at 20˚. Severe, impairing injuries were observed in the foot of standing and hyper‐extended specimens. Strain gauge measurements taken from the lateral calcaneus in the standing and hyper-extended positions were more than double the strain found in specimens with the knee flexed position. The results in this study demonstrate that a vehicle occupant whose posture incorporates knee flexion at the time of an under‐vehicle explosion is likely to reduce the severity of lower limb injuries, when compared to a knee extended position.

Current military conflicts are characterised by the use of the Improvised Explosive Device (IED). Improvements in personal protection, medical care and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to life-long disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centres following a terrorist attack.

Key to mitigating such injuries is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this study, an anti-vehicle underbelly injury simulator, capable of recreating in the laboratory the impulse from an anti-vehicle (AV) explosion, is presented and characterised. Tests were then conducted to assess the simulator's ability to interact with human cadaveric legs. Two mounting conditions were assessed, simulating a typical seated and standing vehicle passenger using instrumented cadaveric lower limbs.

This experimental device, will now allow us (a) to gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) to characterise the dissipating capacity of mitigation technologies, and (c) to assess the biofidelity of surrogates.

Study design: Retrospective, descriptive study

Objectives: To describe the characteristics and outcomes of patients with spinal canal stenosis who suffer significant spinal cord injury (SCI) due to hyperextension injury of the cervical spine. To compare their characteristics and outcomes with all patients suffering traumatic cervical SCI and with the total cohort of patients admitted to a Spinal Injuries Unit for rehabilitation.

Setting: Spinal Injuries Unit (SIU), Princess Alexandra Hospital, Brisbane.

Methods: Demographic, injury and outcome data were obtained from an existing database and by review of the medical records of 575 patients admitted to and discharged from the SIU between July 1st, 1995 and July 1st 2002. Main outcome measures were: change in American Spinal Injury Association (ASIA) scale category, change in ASIA motor score, discharge Functional Independence Measure (FIM) score and change in FIM score, length of stay (LOS), primary means of mobility at discharge and discharge destination. Standard statistical methods were used to compare groups.

Results: A total of 18 (3%) of the 575 patients were found to have cervical canal stenosis and hyperextension injury (the CCS/HI group). This represents 8% of the total group suffering traumatic injury to the cervical spinal cord (the total cervical trauma: TCT group, n = 225). This CCS/HI group was found to have a mean age at injury of 55.1 years compared to 37.1 and 37.8 years respectively for the TCT and total groups. Ninety-four percent of patients were found to have a neurological level at admission at C1–3 or C4–5 compared to 75.6% of the TCT group and only 5.6% of patients had an ASIA Impairment Category A lesion at admission compared to 38.7% of the TCT group. Falls (55.6%) was the most common cause of injury in the CCS/HI group with motor vehicle accidents (33.8%) most common in the TCT group.

The mean change in ASIA motor score between admission and discharge was 34.7 compared to 20.4 for the TCT group. Degree of impairment (measured by a change in ASIA Category) improved in 28% of patients and mean change in total FIM score was 41.3. There was no difference seen with the TCT group. LOS was shorter for these patients (111.1 days vs. 161.6 days). The primary means of mobility at discharge was “walking” for 50% of this group (compared to 28.4% for the TCT group) while the next most common means of mobility was “power wheelchair” at 28% (17% of TCT group). Most patients (55.4%) were discharged to their previous home following rehabilitation and 22.3% were discharged to another rehabilitation unit or acute hospital.

Conclusions: Patients with cervical spinal canal stenosis who suffer hyperextension injury constitute a distinct subgroup with the total group of traumatic cervical spinal cord injuries. This study suggests that they are older at the time of injury, have more rostral cervical injuries, are more likely to have incomplete injuries and that falls is the most common cause of injury. They have greater improvement in motor function but this does not appear to result in greater function at discharge as measured by the FIM. There appears to be a dichotomy with results for mobility at discharge with patients either being able to walk or requiring a power wheelchair. LOS in the SIU is shorter but a higher percentage are discharged to another hospital or rehabilitation unit.

STUDY DESIGN: Retrospective, descriptive study.

OBJECTIVES: To describe the characteristics and outcomes of patients with spinal canal stenosis who suffer significant spinal cord injury (SCI) due to hyperextension injury of the cervical spine. To compare their characteristics and outcomes with all patients suffering traumatic cervical SCI and with the total cohort of patients admitted to a Spinal Injuries Unit for rehabilitation.

SETTING: Spinal Injuries Unit (SIU), Princess Alexandra Hospital, Brisbane.

METHODS: Demographic, injury and outcome data were obtained from an existing database and by review of the medical records of 575 patients admitted to and discharged from the SIU between July 1st, 1995 and July 1st 2002. Main outcome measures were: change in American Spinal Injury Association (ASIA) scale category, change in ASIA motor score, discharge Functional Independence Measure (FIM) score and change in FIM score, length of stay (LOS), primary means of mobility at discharge and discharge destination. Standard statistical methods were used to compare groups.

RESULTS: A total of 18 (3%) of the 575 patients were found to have cervical canal stenosis and hyperextension injury (the CCS/HI group). This represents 8% of the total group suffering traumatic injury to the cervical spinal cord (the total cervical trauma: TCT group, n = 225). This CCS/HI group was found to have a mean age at injury of 55.1 years compared to 37.1 and 37.8 years respectively for the TCT and total groups. Ninety-four percent of patients were found to have a neurological level at admission at C1-3 or C4-5 compared to 75.6% of the TCT group and only 5.6% of patients had an ASIA Impairment Category A lesion at admission compared to 38.7% of the TCT group. Falls (55.6%) was the most common cause of injury in the CCS/HI group with motor vehicle accidents (33.8%) most common in the TCT group.

The mean change in ASIA motor score between admission and discharge was 34.7 compared to 20.4 for the TCT group. Degree of impairment (measured by a change in ASIA Category) improved in 28% of patients and mean change in total FIM score was 41.3. There was no difference seen with the TCT group. LOS was shorter for these patients (111.1 days vs. 161.6 days). The primary means of mobility at discharge was “walking” for 50% of this group (compared to 28.4% for the TCT group) while the next most common means of mobility was “power wheelchair” at 28% (17% of TCT group). Most patients (55.4%) were discharged to their previous home following rehabilitation and 22.3% were discharged to another rehabilitation unit or acute hospital.

CONCLUSIONS: Patients with cervical spinal canal stenosis who suffer hyperextension injury constitute a distinct subgroup with the total group of traumatic cervical spinal cord injuries. This study suggests that they are older at the time of injury, have more rostral cervical injuries, are more likely to have incomplete injuries and that falls is the most common cause of injury. They have greater improvement in motor function but this does not appear to result in greater function at discharge as measured by the FIM. There appears to be a dichotomy with results for mobility at discharge with patients either being able to walk or requiring a power wheelchair. LOS in the SIU is shorter but a higher percentage are discharged to another hospital or rehabilitation unit.