Introduction: Neck pain often arises without any evident trauma suggesting that everyday loading may cause fatigue damage to spinal tissues. However, little is known about the forces acting on the cervical spine in everyday life. The purpose of this study was to determine spinal compressive forces using an electromyo-graphic (EMG) technique.

Methods: Eight subjects performed a number of tasks while cervical flexion/extension and surface EMG activity of upper trapezius and sternocleidomastoid were measured. Dynamic EMG signals were corrected for contraction speed, using a correction factor obtained from lumbar muscles, and were then compared with isometric calibrations in order to predict moment generation. Calibrations were performed in different amounts of cervical flexion/extension by each subject to account for changes in the EMG-moment relationship with muscle length. Compressive force on the C7-T1 intervertebral disc was determined by dividing the generated moments by the resultant lever arm of flexor or extensor muscles obtained from MRI scans on the same subjects.

Results: Peak values (mean ± SD) of extensor and flexor moments increased from 1.9±1.6Nm and 1.4±1.0Nm respectively in standing to 52.7±32.2Nm and 4.2±1.8Nm when lifting above the head. Resultant muscle lever arms ranged between 3.0–5.2cm and 1.6–3.5cm for extensor and flexor muscles respectively. Therefore, peak compressive forces on the C7–T1 disc were 110±74N in standing and 1570±940N during overhead lifting.

Conclusion: Neck muscles generate high forces in activities such as overhead lifting. If applied on a repetitive basis, such forces could lead to the accumulation of fatigue damage in life.

Objective: Axially loaded MRI simulates imaging of the lumbar spine in the standing position and is useful in the assessment of spinal stenosis[1]. This study determines the ability of axially loaded spinal MRI to assess Cobb angle in patients with idiopathic scoliosis.

Design: Prospective study. Newly diagnosed patients with idiopathic scoliosis were referred for MRI of the whole spine. Cobb angle measurements were made from erect AP spinal radiographs prior to MRI. Coronal MR images of the thoracic and/or lumbar spine were obtained prior to and following loading of the spine in an MR compatible compression device (Dynawell). Cobb angle measurements were made on unloaded and loaded MRI studies using the same reference points as on radiographs. Radiographic and MRI Cobb angle measurements were compared. Informed consent was obtained from all patients and the study was approved by the local Ethics Committee.

Subjects: Five patients, all females with mean age 14 years (range 12–16 years) were included in the study. Outcome Measures: Six curves were compared on pre-referral erect radiographs, unloaded and loaded MRI studies, 2 in the thoracic region and 4 in the thoracolumbar region.

Results: Curve characteristics and Cobb angle measurement on radiographs vs. axial unloaded and loaded MRI were as follows: Curve 1; T4-T12, 45°, 36° and 41°. Curve 2; T10-L4, 52°, 22° and 30°. Curve 3; T10-L4, 45°, 36° and 38°. Curve 4; T6-T10, 42°, 22° and 22°. Curve 5; T11-L3, 43°, 32° and 43°. Curve 6; T11-L3, 34°, 11° and 31°

Conclusions: Axial loading increases MRI Cobb angle measurements compared to unloaded studies. Initial results suggest that axial loaded MRI using the Dynawell Compression device may allow comparative measurement of Cobb angle to erect radiographs in the thoracolumbar region, but not in the thoracic region. This is likely related to the loading characteristics of the compression device, which is designed to concentrate loading in the lumbar region. Modification to include loading of the thoracic spine may improve results. The technique has the potential to replace radiography and thus reduce radiation burden to young adolescents with some types of idiopathic scoliosis.

To identify any shoulder joint pathology on MRI of young patients (< 35 yrs) with a single simple antero- inferior dislocation of the shoulder at minimum 5-year follow-up.

Patients aged 16–35 years with a single antero-inferior shoulder dislocation with a minimum 5-year (range5–9 yrs) follow-up were identified. A history of recurrent dislocation or surgery excluded patients from study. Ethical approval was obtained and identified patients were asked to volunteer for clinical review and have an MRI scan. Shoulders were clinically examined, noting specifically any signs/symptoms of rotator cuff pathology or instability. All shoulders were imaged with a 1.5 Tesla open MRI scan to assess any pathology.

In a 5-year period (1994–1998), 349 patients sustained an antero-inferior dislocation. 251 were in patients aged 35 years or less. 136 of these were excluded either due to recurrent dislocations. 62 patients were lost to follow-up of 53 eligible patients 7 could attend for study. Only one patient had a positive anterior apprehension sign but he did not have any symptoms of instability in his daily activities or sport. The only abnormality demonstrated on MRI was of a united greater tuberosity fracture in one shoulder. The glenolabral and bicipitolabral complexes were normal in all shoulders imaged.

Bankart lesions, both bony and labral, are known to be associated with recurrent anterior shoulder dislocations.This study has shown no shoulder joint pathology on MRI at minimum 5-year follow-up in young patients who have sustained a single antero-inferior shoulder dislocation, confirming that labral pathology seems to be important in recurrent dislocations. Further study to image more patients is underway. These results indicate that acute imaging of dislocated shoulders may be useful to help predict young patients who are unlikely to re-dislocate and thus unlikely to require surgery.