Introduction: Compared with open instrumented anterior spinal fusion for adolescent idiopathic scoliosis (AIS), endoscopic surgery offers clinical benefits that include reduced pulmonary morbidity and improved cosmesis. However, quantitative data on the radiological improvement of vertebral rotation using this method is limited. The aim of this study was to measure pre-operative and postoperative axial vertebral rotational deformity at the curve apex in endoscopic anterior instrumented scoliosis surgery patients using computed tomography (CT), and assess the relevance of these findings to clinically measured chest wall rib hump deformity correction.

Methods: Between November 2002 and August 2005, twenty patients with right-sided thoracic curves underwent endoscopic single-rod anterior instrumented fusion. Pre and post surgical axial vertebral rotation was measured at the curve apex on preoperative and two-year postoperative CT using Aaro and Dahlborn’s method. Rib hump deformity correction was retrieved from a surgical database and correlated to the CT findings. Linear regression was used to investigate the correlation between apical vertebral rotation measured on CT and rib hump measured using a scoliometer.

Results: The mean angle of correction achieved in axial vertebral body derotation at the apical vertebra as measured by CT was 7.9°. This equated to a 43% improvement (range 20–90%). The preoperative and postoperative clinical measurements i.e. rib hump deformity correction, correlated significantly with CT measurements using regression analysis (p=0.03) and the mean improvement in rib hump deformity was 55%.

Conclusion: To our knowledge, this is the first quantitative CT study to confirm that endoscopic anterior instrumented fusion for AIS substantially improves the axial vertebral body rotational deformity at the apex of the curve. The margin of correction of 43% compares favourably historically published figures for all-hook-rod constructs in posterior spinal fusion. In addition, the CT measurements obtained significantly correlated to the clinical outcome of rib hump deformity correction.

Introduction: The occurrence of non-union following instrumented scoliosis correction may predispose to pseudarthrosis and subsequent implant failure. Although non-union is often multifactorial, it is widely accepted that bone graft of adequate quality and quantity is fundamental to achieve solid fusion. Conventionally, autologous rib graft or iliac crest harvest has been utilised for endoscopic anterior instrumented scoliosis surgery. However, these techniques increase the operative duration and cause donor site morbidity, both of which may lengthen hospital stay. Alternatives such as allograft bone and bone morphogenetic proteins have gained more widespread use and may improve fusion rates although this remains controversial. The aim of this study was to compare two-year postoperative fusion rates for a series of patients who underwent endoscopic anterior instrumentation for thoracic scoliosis utilising various bone graft types.

Methods: 19 patients who had undergone endoscopic anterior instrumented scoliosis correction using identical instrumentation (4.5mm diameter titanium anterior rod and vertebral body screws, Eclipse, Medtronic) between May 2000 and August 2005 were identified from a surgical database of 132 consecutively treated individuals. All patients received bone graft to supplement thoracic fusion. Discectomy was performed at the levels to be instrumented and intervertebral spaces were packed with autologous rib heads (8 patients), iliac crest (1 patient), or mulched femoral head allograft (10 patients). The quality of thoracic fusion and implant integrity were evaluated two years following scoliosis correction using low-dose CT performed in accordance with local ethical approval. The intervertebral fusion was assessed using a modified Sucato method (1). Each level was graded using a 4-point scale based on calculated percentage of fusion across the disc space. 0 points indicated no fusion; 1 point, fusion < 25%; 2 points, fusion between 25 and 50%; 3 points, fusion between 50 and 75%; 4 points > 75% or complete fusion. The fusion was considered solid with a score of 3 points or more. Data was analysed with non-parametric tests using a significance level of 0.05.

Results: Of the cohort, nine had evidence of implant failure with rod fracture. All implant failures occurred in the group who received either rib head or iliac crest graft. No rod fractures were identified in the femoral allograft group. The mean fusion grade in the autologous bone graft group was 1.91 whereas in the allograft group this was 3.30 (95% confidence intervals 1.38–2.44 and 2.99–3.61 respectively) with a statistically significant difference in fusion rates between these two groups (p=0.001).

Discussion: This study demonstrated significantly better rates of thoracic fusion in endoscopic anterior instrumented scoliosis correction using mulched femoral allograft compared with autologous rib heads and iliac crest graft. This could be partly explained by the difficulty obtaining sufficient quantities of autologous graft. The lower fusion rate seen in the autologous graft group appears to predispose to rod fracture although the longer-term clinical consequence of implant failure in this group is not clear and warrants further study.

Introduction: Open instrumented anterior spinal fusion for adolescent idiopathic scoliosis (AIS) is a proven technique for vertebral derotation that, compared with posterior spinal fusion procedures, invariably requires fewer distal fusion levels to be performed. With the advent and evolution of endoscopic anterior instrumentation, further clinical benefits are possible such as reduced pulmonary morbidity, improved cosmesis and less postoperative pain. However, quantitative data on the radiological improvement of vertebral rotation using this method is limited. The aim of this study was to measure preoperative and postoperative axial vertebral rotational deformity at the apex of the curve in endoscopic anterior instrumented scoliosis surgery patients using computed tomography (CT), and assess the relevance of these findings to clinically measured chest wall rib hump deformity correction.

Methods: Between November 2002 and August 2005, adolescent idiopathic scoliosis patients with right-sided thoracic major curves were selected for endoscopic single-rod anterior fusion by the senior authors. Low-dose pre-operative CT was performed as described previously (1) and two-year postoperative CT was also performed on consenting patients in accordance with local ethical committee approval. The pre and post surgical axial vertebral rotation was measured at the curve apex using Aaro and Dahlborn’s method (2). Intraobserver and interobserver variability was assessed. Additional clinical information such as rib hump deformity correction and change in the Cobb angle was retrieved from a surgical database and correlated to the CT findings. Least squares linear regression was used to investigate the correlation between apical vertebral rotation measured on CT and rib hump measured using a scoliometer.

Results: Twenty patients were included in the study. The mean angle of correction achieved in axial vertebral body derotation at the apical vertebra measured by CT was 7.9° (median preoperative angle 17.3° [range 12.5° to 27.3°] and median postoperative angle 10.3° [range 1.8° to 18.1°]. This equated to a 43% improvement (range 20–90%). The preoperative and postoperative clinical measurements i.e. rib hump deformity correction, correlated significantly with CT measurements using regression analysis (p=0.03) and the mean improvement in rib hump deformity was 55% (median preoperative 15.0° [range 10° to 30°] and median postoperative 7.0° [range 4° to 10°]). 95% confidence intervals for intraobserver and interobserver validity were within the ranges ±4.5° to ±6.4°.

Discussion: We believe this is the first quantitative CT study to confirm that endoscopic anterior instrumented fusion for AIS substantially improves the axial vertebral body rotational deformity at the apex of the curve. The margin of correction of 43% compares more favourably than the historically published figure of 24% in a cohort of patients with all-hook-rod constructs used for posterior spinal fusion (3). Patient age and gender demographics, curve magnitude and curve types in the historical study were similar to our group, and an identical CT protocol for measuring vertebral derotation was utilised. In addition, the CT measurements obtained significantly correlated to the clinical outcome of rib hump deformity correction.

Adult polytrauma patients are at high risk of developing acute lung injury. Fat embolism or traumatic pulmonary contusions are the usual causes and respiratory support is often indicated. Conventional treatment with intubation and positive pressure ventilation is sufficient for most patients with moderate lung injury. However, for patients with acute severe respiratory failure who remain hypoxic despite maximal pressure ventilation, the mortality rate exceeds 60%.

We have reviewed the use of extracorporeal membrane oxygenation (ECMO) in adult trauma patients with acute severe respiratory failure. ECMO was performed at a tertiary unit in an intensive care setting. Using an external oxygenation circuit the injured lungs were “rested” until pulmonary function recovered. With this method ventilation pressures could be reduced and ventilator-related pulmonary barotrauma was limited.

Between 1992 and 2000, 28 adult trauma patients were referred for ECMO. This group of patients were at the severe end of the ARDS spectrum with an average Murray Lung Injury score of 3.2. The most common injuries included long bone or pelvic fractures, and blunt chest trauma. Over 50% of patients with long bone fractures treated with ECMO had developed respiratory failure following internal fixation.

Overall survival was 71.4%. Statistical analysis demonstrated that outcome was not related to age, injury severity score, ECMO duration or the degree of lung injury as classified by the Murray scoring system. Mortality was usually a consequence of trauma-related sepsis or cardiogenic failure. Although the study group is small due to the relatively small number of referral, we believe that ECMO may confer a survival advantage. Since orthopaedic surgeons often play a pivotal role in the management of the patient with multiple injuries and are also increasingly involved in their intensive care therapy, we feel an awareness of this technique could offer benefit to a predominantly young healthy population.