An accurate method of measuring shoulder sling compliance: a validation study

Background The effect of postoperative shoulder sling compliance on surgical outcomes is unknown. The goal was to determine an accurate method to measure sling compliance. We compared volunteer recorded sling wear time with temperature-based sensors to monitor sling compliance. Methods Data loggers sutured at three locations measured heat generated in 15-minute intervals. Slings wearers logged sling wear to accurately cross-reference with temperature sensors. Secondary experiments analyzed whether surrounding ambient temperature can be discerned from actual sling wear. We created an algorithm to describe actual sling wear time as a function of heat recorded and calculated percent wear accuracy. Results The modified sling was worn for 172 h. The algorithm modeled sling on/off times by analyzing cutoff temperatures. Diagnostic accuracy was >99 % for the three locations, with no statistically significant differences among them. Compared with sling wear, ambient temperature took longer to reach critical temperature values determined by the algorithm, helping distinguish compliance from false positives. Conclusions The described algorithm can effectively quantify shoulder sling wear time based on heat-generated sensor readings. False positives from ambient temperature are minimal. This measurement method could be used to study the relationship between postoperative sling use and functional outcomes after shoulder surgery.

Development and evaluation of a novel flex sensor-based glenohumeral subluxation degree assessment for wearable shoulder sling

Background: Glenohumeral subluxation (GHS) is reported in as many as 81% of patients with stroke, which presents considerable challenges for individuals involved in stroke rehabilitation. During rehabilitation, the joint head of the glenohumeral joint was maintained in the socket by wearing a GHS shoulder sling. To ensure that the glenohumeral joint head is in the socket, an orthosis is required to automatically adjust the degree of orthosis according to the degree of GHS. However, there is currently no wearable method for assessing the degree of GHS. This study aims to develop a GHS assessment method for patients with stroke that has the potential to be integrated into a wearable shoulder sling.Methods: To that end, we developed a GHS assessment method for patients with stroke based on a flex sensor, which has the potential to be integrated into a wearable shoulder sling. Seventeen patients with stroke in a diverse degree of GHS were recruited for the study. The curvature difference of the affected shoulder in the subluxation and reduction states was collected by flex sensor to calculate the degree of GHS (AGTD). Meanwhile, the GHS degree, calculated as the acromion–greater tuberosity distance di.fference (AGTD) of the affected and unaffected shoulder, was measured by the gold-standard radiographic assessment.Results: The GHS degree measurement by flex sensor and radiographic assessment has strongly correlated (r = 0.92, p < 0.01). The relationship of GHS degree measured by radiographic assessment (AGTD) and flex sensor (AGHS) is linear according to an interpolating curve with an equation: AGHS = 0.767AGTD + 1.781 (R2 = 0.84, RMSE = 1.61). The method has excellent reliability with R = 0.87, CI = 95% for assessment of GHS degrees.Conclusions: The proposed method demonstrates good performance, is wearable, easy to use, and allows automatic measurements, so as to be a valuable method to assessment of GHS.

A comparative study to assess the satisfaction with clinical outcome of the patients suffering from hemiplegic shoulder subluxation and undergoing rehabilitation with and without Bobath shoulder sling

Background: Hemiplegic shoulder subluxation is one of the most common factor for post-stroke upper limb disability. There are various ways to assess its outcome during rehabilitation, but the assessment of patients’ satisfaction with the shoulder support is often missed. This study was done to compare those patients’ satisfaction with clinical outcome who were undergoing same rehabilitation programme for their hemiplegic shoulder subluxation with and without Bobath shoulder sling.Methods: This prospective controlled interventional study was conducted on 30 patients of both sexes within the age group of 45-65 years with hemiplegic (duration <6 weeks) gleno-humeral subluxation (GHS). Screening of GHS was done by palpation. They were randomly divided in two groups of same number (15 in each group) and put on rehabilitation protocol with group 1 receiving Bobath shoulder Sling as support for subluxed shoulder and group 2 continuing without it. Patients’ satisfaction on clinical outcome was measured with clinical global impression-improvement (CGI-I) scale. Data were collected at 6 weeks (first follow up-visit), 12 weeks (visit 2) and at the end of the study i.e. 24 weeks (visit 3).Results: Statistically significant difference (p=0.003) in mean score of CGI-I at visit 1 suggested significant improvement for group 1 but no statistically significant difference in improvement was noticed between the groups at visit 2 (p=1.000) and visit 3 (p=0.724).Conclusions: Use of support for hemiplegic shoulder is beneficial only during early days of rehabilitation, not on prolonged use.

Effects of cross-education on the muscle after a period of unilateral limb immobilization using a shoulder sling and swathe

The purpose of this study was to apply cross-education during 4 wk of unilateral limb immobilization using a shoulder sling and swathe to investigate the effects on muscle strength, muscle size, and muscle activation. Twenty-five right-handed participants were assigned to one of three groups as follows: the Immob + Train group wore a sling and swathe and strength trained ( n = 8), the Immob group wore a sling and swathe and did not strength train ( n = 8), and the Control group received no treatment ( n = 9). Immobilization was applied to the nondominant (left) arm. Strength training consisted of maximal isometric elbow flexion and extension of the dominant (right) arm 3 days/wk. Torque (dynamometer), muscle thickness (ultrasound), maximal voluntary activation (interpolated twitch), and electromyography (EMG) were measured. The change in right biceps and triceps brachii muscle thickness [7.0 ± 1.9 and 7.1 ± 2.2% (SE), respectively] was greater for Immob + Train than Immob (0.4 ± 1.2 and −1.9 ± 1.7%) and Control (0.8 ± 0.5 and 0.0 ± 1.1%, P < 0.05). Left biceps and triceps brachii muscle thickness for Immob + Train (2.2 ± 0.7 and 3.4 ± 2.1%, respectively) was significantly different from Immob (−2.8 ± 1.1 and −5.2 ± 2.7%, respectively, P < 0.05). Right elbow flexion strength for Immob + Train (18.9 ± 5.5%) was significantly different from Immob (−1.6 ± 4.0%, P < 0.05). Right and left elbow extension strength for Immob + Train (68.1 ± 25.9 and 32.2 ± 9.0%, respectively) was significantly different from the respective limb of Immob (1.3 ± 7.7 and −6.1 ± 7.8%) and Control (4.7 ± 4.7 and −0.2 ± 4.5%, P < 0.05). Immobilization in a sling and swathe decreased strength and muscle size but had no effect on maximal voluntary activation or EMG. The cross-education effect on the immobilized limb was greater after elbow extension training. This study suggests that strength training the nonimmobilized limb benefits the immobilized limb for muscle size and strength.