“Rhin sling,” A Novel Type of Shoulder Sling in Post-Stroke Shoulder Subluxation: A Case Report

Shoulder slings are often used in clinical practice to support the hemiplegic arm and to prevent or treat glenohumeral subluxation. There are 3 types of shoulder orthosis: proximal humeral support (P-S), whole arm with elbow flexion support (Wh-S), and proximal-distal support (P-D-S). A systematic review revealed that the Wh-S type provides the most significant reduction, followed by the P-D-S and P-S types [1]. While the Wh-S type offers the most significant reduction, it could restrict the elbow to a bent position, potentially leading to spasticity or elbow flexion contracture in post-stroke patients. On the other hand, the P-D-S and P-S types allow for a natural swing during walking [2].

Traditional assistive devices may often pose common issues that limit the effective correction of shoulder subluxation. First, to prevent or correct glenohumeral subluxation caused by gravity, it is necessary to apply traction to 2 anchoring points proximal to and distal to the shoulder joint. Achieving complete correction requires sufficient traction force to overcome the arm’s weight and lift it in the opposite direction of gravity. However, conventional shoulder slings are usually ready-made and, therefore, need an easily adjustable traction device, and correction while applying adjustable tension per each shoulder problem is complex. Individual patients may have different levels of subluxation, and traction devices that can fine-tune the tension with adjustable levels of support as the patient’s condition improves are warranted. Second, since the traction force operates between the 2 support points (proximal and distal), the range of motions in the joint located between these points is limited. For example, the GivMohr Sling decreases the range of movement in the glenohumeral, elbow, and wrist joints [3]. Third, to correct a subluxed shoulder joint, it is necessary to apply traction to the skeleton. However, soft tissues such as muscles, connective tissues, and the skin are situated between the assistive device and the skeletal frame. This can result in the skeletal structure being pulled away from the body in the direction of gravity by the assistive device and may cause skin problems. When the upper arm is the fixation point (e.g., Rolyan Humeral Cuff Sling), the cylindrical structure of the upper arm causes it to slip downward away from the assistive device [4]. Despite the constant update of conventional slings and the introduction of novel types, however, no slings can address all these issues. A novel type of shoulder sling that can address these limitations is needed.

Therefore, through this case report, we would like to introduce a novel type of shoulder sling for hemiplegic stroke patients, with a unique reel device that allows easy adjustment and correction of post-stroke shoulder subluxation.

This case report introduces a novel type of sling for glenohumeral subluxation with its corrective effects illustrated by radiographic images that have proven its immediate and maintenance effects after application. The 2 patients had variable but severe degrees of shoulder subluxation. The corrective effects were observed immediately after application and were well maintained after hours of sling application. Both patients showed good tolerance to this novel type of device.

Only some orthoses that utilize reel devices, such as ankle-foot orthotics, are already available, but there have been no reported cases of their application in shoulder slings. This case report shows promising results of the clinical utility of the reel traction device that allows freedom of shoulder motion with accurate correction effects that can be adjustable to each patient’s unique shoulder subluxation level with a simple reel device. The reel can be adjusted while allowing the shoulder joint a free range of motion. Preserved range of motion is essential because it enables some of the daily activities of the affected upper limb after correction [7], and arm sway during walking is not restricted. This sling’s reel traction system allows corrective force to be adjusted according to the severity of the patient’s dislocation. These unique features allow precise and customizable adjustments according to each patient’s unique level of shoulder subluxation and motor recovery.

The Rhin sling distinguishes itself from traditional shoulder orthoses like the Bobath sling or Givmohr sling by addressing not only vertical subluxation but also offering the capability to correct horizontal subluxation [3]. The follow-up images showed decrease of both the vertical and horizontal distances. The latter is crucial since horizontal shoulder subluxation can cause supraspinatus tendinitis [8].

This case study has a few limitations. First, as mentioned before, we only observed changes following the application of the Rhin sling for a maximum of 2 hours. Considering previous research that involved observations extending several weeks later [9], a long-term assessment is essential to confirm the Rhin sling’s sustained corrective effects. Second, data related to patients’ pain scales, like the Visual Analog or Numerical Rating Scale, were unavailable in this case study. Hemiplegic shoulder pain is associated with the loss of motion in the affected joint and is one of the factors causing discomfort in the patient’s daily life [10]. No study has yet determined whether subluxation and pain can be prevented by immediate post-stroke application of orthoses. Subsequent research should include observations related to this aspect. Nonetheless, these cases show the impetus and need to carry out future clinical trials with a large sample size to confirm this novel type of sling’s corrective effects and compare these effects to other conventional shoulder slings.

In conclusion, these 2 cases confirm the feasibility of this new sling type and the potential clinical benefits in hemiplegic stroke patients with shoulder subluxation. Future prospective studies with a more significant number of participants are warranted further to validate the patients’ compliance and corrective effect of this novel sling with a reel-traction design and its long-term effect on spasticity, shoulder range of motion and hemiplegic shoulder pain.