Subacromial impingement syndrome
Sometimes called subacromial impingement sometimes called shoulder impingement or rotator cuff impingement refers to the painful shoulder especially when the person lifts his arm to the front or the side.
This term usually came from the belief that the subacromial space, was narrowing and pinching the rotator cuff, leading to pain and dysfunction.
However, the latest studies have shown that this is not true and not backed up by evidence and did update in a lot of articles our understanding of subacromial pain.
The origin of the term and where it comes from:
Initially, the name is given by a surgeon named Dr. Neer who coined the term in 1983.
During that time, the biomedical model of pain management and biomechanics around pain were the leading perspective on why someone had pain.
Decompressing the shoulder was a common surgery, and it was prescribed when someone has chronic bursitis, complete or partial tear of the supraspinatus muscle.
Dr. Neer was very well-known and a well-regarded surgeon. As its popularity grew, the name became known as subacromial impingement syndrome.
Current evidence suggestions
The original theory was that the supraspinatus tendon was impinging between the acromion and humerus which will cause pain.
A study was conducted in 1996 conducted by Brossman et al where they examined the movement of the shoulder with an x-ray and MRI. In their study, they found that the supraspinatus impinged between the acromion and greater tuberosity of the humerus at 30 degrees of shoulder flexion and abduction. This is in stark contrast to the original theory as the impingement was not only occurring at a very low angle, but it also did not match up with when we would expect symptoms.
The study found that peak impingement of the supraspinatus muscle was seen at 60 degrees of flexion, internal rotation, and abduction of the shoulder. This is not the position in that we see most complaints.
Kolk et al did a study with a 12-year follow-up with patients who had been randomly assigned to either a bursectomy group or to a bursectomy and acromioplasty group. No significant differences were found between the two groups. This challenges the impingement theory further.
Given that most people seek out care due to pain that is limiting their daily function, we should consider pain in our working operation of the condition.
Neer’s theory highlighted the fact that impingement will lead to impairment of the shoulder through damaging the rotator cuff which will cause pain. As we mentioned above, we don’t know what is necessarily the cause of impingement syndrome – so is tissue damage the problem?
If someone has pain, we used to link it directly to damage in the tissue, this opens up a large amount of literature to consider. Over the years, doctors and clinicians assumed that when a person had pain, it was related to damage to the tissue. What we have learned over the last few decades was far from accurate.
A study in 2007 done by Moseley details that our pain behavior does not reflect the current status and mentions that the pain is objective and more complex than that. We have dug more into theories from the gate control theory, the biopsychosocial model to the neuromatrix theory. And began to consider the pain topic very differently and not only consider its damage to the tissue.
The Internal Association for the Study of Pain has proposed this updated version of a definition for pain:
An aversive sensory and emotional experience is typically caused by or resembling that caused by actual or potential tissue injury.
What we can conclude is that they didn’t exclude the possibility of damaged tissue, but don’t indicate that this is always the case.
Various studies show the large range of abnormalities seen on images. From bursitis to tendonitis, partial tear full tear, calcification, and many more. But what we see most of the time does not match the symptoms or the experience of the client. As a consequence of this, we need to update the classification of what is normal and what is abnormal and clearer explanations from imaging.
A study done by Firstly, Cuff & Littlewood 2017 found that when patients are experiencing shoulder, they do believe that there is damage in a specific tissue and that only imaging would be able to give them an appropriate diagnosis of their condition.
Patients often believe that scans can provide a definitive answer that confirms what is wrong and that it can deliver certainty to their current uncertainty. They do also believe if a structural factor is behind the cause of their pain, surgery is the only way to go.
Recently, there has been a shift away from the terminology of “shoulder impingement” or “subacromial impingement” and towards new terminology such as “subacromial pain syndrome”. The purpose is to help transition away from the term impingement which we now don’t represent what is happening.
Here are 2 more videos that can be helpful for shoulder pain:
Link 1: https://www.instagram.com/p/CA70KftpJXH/
Link 2: https://www.instagram.com/p/B-60sYXJMBV/
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References
- Diercks R, Bron C, Dorrestijn O, et al. Guideline for diagnosis and treatment of subacromial pain syndrome: a multidisciplinary review by the Dutch Orthopaedic Association. Acta orthopaedica. 2014; 85(3):314-22.
- Cuff A, Littlewood C. Subacromial impingement syndrome – what does this mean to and for the patient? A qualitative study. Musculoskeletal science and practice. 2018;33:24-28.
- Neer CS. impingement lesions. Clin Orthop Relat Res. 1983;173;70-77.
- Neer CS. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. The Journal of bone and joint surgery. American volume. 1972; 54(1):41-50.
- Mackenzie TA, Herrington L, Horslsey I, Cools A. An evidence-based review of current perceptions with regard to the subacromial space in shoulder impingement syndromes: Is it important and what influences it? Clinical Biomechanics. 2015;30(7):641-648.
- Lewis J. The End of an Era? J Orthop & Sports Phys Ther. 2018;48(3):127-129.
- Brossman J, et al. Shoulder impingement syndrome: influence of shoulder position on rotator cuff impingement- an anatomic study. American Journal of Roetgenology. 1996;167(6):1511-1515.
- Kolk A, Thomassen BJW, Hund H, et al. Does acromioplasty result in favorable clinical and radiologic outcomes in the management of chronic subacromial pain syndrome? A double blinded randomized clinical trial with 9 to 14 years’ follow-up. J Shoulder Elbow Surg. 2017;26:1407- 1415. https://doi.org/10.1016/j.jse.2017.03.021
- Moseley LG. Reconceptualizing pain according to modern pain science. Physical Therapy Reviews. 2007;12(3):169-178.
- International Association for the Study of Pain. Proposed New Definition of Pain. https://www.iasp-pain.org/PublicationsNews/NewsDetail.aspx?ItemNumber=9218
- Teunis T, Lubberts B, Reilly BT, Ring D. A systematic review and pooled analysis of the prevalance of rotator cuff disease with increasing age. J Shoulder Elbow Surg. 2014;23(12):1913-1921.
- Minagawa H, Yamamoto N, et al. Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: From mass-screening in one village. J Orthop. 2013;10(1):8-12.
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