Nine months ago, I shared a blog post that was an example of medical writing focused on thoracic outlet syndrome (TOS). As is my regular habit whenever I upload a blog post, I announced on my Facebook and LinkedIn accounts that it was live. Generally speaking, the reactions I get to these announcements are from people I know. However, about seven months after I announced my post about TOS on LinkedIn, someone I wasn’t connected to at the time commented that she has TOS and has been suffering terribly from it.
This interaction let me realize that my blog writing has the capacity to reach people who need to see what I write. As such, I’ve decided to share another piece of medical writing in this blog post, this time focused on another rare condition, quadrilateral space syndrome, which can be a complication of some TOS surgeries. Perhaps what I write here can help someone who is suffering from this condition.
What is Quadrilateral Space Syndrome?
Quadrilateral space syndrome (QSS), also known as quadrangular space syndrome, is the painful compression of the axillary nerve as it passes through the shoulder. An artery called the posterior humeral circumflex artery can also be compressed in some cases, as described in an article by Dr. Patrick T. Hangge and several of his colleagues in the Journal of Clinical Medicine. The condition gets its name because the nerve and/or artery compression occurs when the space between four structures—the teres minor muscle, the teres major muscle, the long head of the triceps muscle, and the humerus bone in the arm—becomes too small for the nerve and/or artery to pass through comfortably.
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Quadrilateral Space (Radiopaedia/Craig Hacking) |
What Symptoms are Caused by QSS?
Patients with QSS often report numbness, weakness, and pain in the shoulder or upper arm due to nerve compression, according to Dr. Hangge and his colleagues. They also explained that if the artery is also compressed, patients might experience paleness or coldness in the arm or shoulder. Both types of patients experience tenderness when the area of the quadrilateral space is touched.
Many patients with QSS also experience difficulty with particular arm movements, as noted by Dr. Elliott B. Tapper in an article published by WikiDoc. These movements include external rotation, adduction, and extension of the upper arm. In other words, people with QSS have trouble with rotating the arm outwardly as well as with raising and lowering the arm to the front and side.
How is QSS Diagnosed?
Arriving at a QSS diagnosis can be challenging. In fact, Dr. Tapper pointed out that frequently the condition is misdiagnosed. He even noted that sometimes the symptoms of QSS are wrongly attributed to a mental or emotional cause, rather than to a physical one.
Frequently, a QSS diagnosis is arrived at by excluding other possible causes of the symptoms, as Dr. Hangge and his colleagues detailed. Some of the other conditions they indicated should be ruled out are a rotator cuff injury, a labral injury, a problem with the cervical spine, arthritis of the glenohumeral joint, a brachial plexus injury, an injury to the suprascapular nerve, and thoracic outlet syndrome. All of these conditions can have symptoms similar to those experienced by someone with QSS.
The most common tests ordered in attempting to diagnose QSS are MRI, ultrasound, and EMG, according to Dr. Tyler D. Kemp and his associates writing in the Journal of Chiropractic Medicine. They pointed out, though, that these tests can result in false negatives, which means none of them are considered ideal in definitively establishing that a patient has QSS. However, the tests can be useful in ruling out other causes of shoulder pain.
Another tool for diagnosing QSS is to give an injection of a numbing agent and/or a steroid into the quadrilateral/quadrangular space. If pain relief results, QSS is likely the cause. Dr. Shi-Hao Feng and colleagues writing in the journal Pain Medicine explained that this procedure is often performed under ultrasound guidance. Furthermore, Dr. Hamilton Chen and his colleague Dr. Vincent Reginald Narvaez proposed in their article in the journal Case Reports in Orthopedics that this procedure can be particularly helpful when other diagnostic tests are inconclusive.
Who Gets QSS?
QSS is most commonly seen in young athletes who participate in sports involving overhead motions of the arms, such as volleyball, baseball, swimming, and football, according to Kemp and his colleagues as well as Hangge and his colleagues. Others who experience QSS might have suffered a shoulder dislocation, as discussed by Kemp and his associates. An article in Radiopaedia edited by musculoskeletal radiologist Dr. Henry Knipe also mentioned cysts, tumors, or aneurysms as possible causes of the condition.
Another possible cause of QSS is a complication resulting from surgery. The Radiopaedia article mentioned that crush or traction injuries can cause CSS. These injuries might occur during some surgeries. In fact, Dr. Motohiro Nishimura and his colleagues wrote about this situation in the journal The Annals of Thoracic Surgery, where they outlined a case of QSS caused by a thoracic surgery that required positioning the arm in such a way as to stretch the axillary nerve and/or the quadrilateral/quadrangular space area.
How Common is QSS?
QSS is considered a rare condition. Notably, every article I read in researching this condition referred to it as rare. In fact, in his article, Dr. Tapper indicated that QSS accounts for only 0.8% of all cases of shoulder pain.
One anecdote that illustrates the rarity of QSS is my experience trying to find doctors who have treated this condition in order to learn more about it from them. In all, I spoke with five doctors who might be expected to have experience treating QSS. One doctor, a pain specialist, said she had never heard of QSS. Another, a physical medicine and rehabilitation specialist, said he had encountered only one case in 15 years of practice.
The other three doctors I spoke to were all orthopedists. One said he had never encountered a case and had only learned about the condition through textbooks. Another said he had seen several cases but had only operated on someone with the condition four times in his 10-year-long career.
The fifth doctor I spoke to had more experience with the condition. He claimed to perform 10-20 surgeries on patients with QSS annually. Additionally, a perusal of this doctor’s website indicated he had contributed to two scientific articles focused on the axillary nerve.
Admittedly, my survey of doctors was completely unscientific, but it indicates how challenging it can be for patients with rare conditions to find a high-volume practitioner for treatment. As Dr. Jonathan Cluett, a board certified orthopedic surgeon writing for Verywell Health, explained, being treated by a high-volume practitioner has many benefits, including fewer complications, shorter hospital stays, and less need for corrective surgeries.
How many surgeries qualify a doctor as a high-volume practitioner? Dr. Cluett indicated that for common surgical procedures, including for carpal tunnel syndrome, rotator cuff injury, and the like, a doctor should have been performing these surgeries for at least five years at a rate of 30 per year to qualify. He also indicated that for less common conditions, such as shoulder replacement, a doctor should have performed at least 30 surgeries of that type to be considered high-volume.
Using these criteria, only one doctor I spoke to would qualify as a high-volume practitioner for QSS. This situation helps illustrate the rarity of the condition. Perhaps if the condition were not so rare, more doctors would have more experience treating it.
How is QSS Treated?
Although surgery is an option for treating QSS, it is generally considered a last resort. As Dr. Kemp and his associates outlined in their article and Dr. Hangge and his associates also described, first-line treatments often begin with physical therapy. This therapy should focus on range of motion and strengthening, particularly by mobilizing the shoulder joint, manipulating the muscles surrounding the quadrilateral space, and strengthening the rotator cuff muscles.
If physical therapy is not successful in resolving QSS symptoms, the same type of injection used for diagnosis can also be helpful as a treatment, as Dr. Kemp and colleagues, Dr. Hangge and colleagues, and Dr. Feng and colleagues all explained. It should be noted that in order for pain relief to be long lasting, a steroid must be injected along with the numbing agent used in the diagnostic injection procedure. This is because the numbing agent used is a short-term medication, while the effects of steroids are known to linger for a longer time.
When all other treatments have failed, surgery is an option. The procedure used is decompression of the quadrilateral/quadrangular space. This procedure has been described in detail by Dr. Lucy E. Meyer and her colleagues in the Video Journal of Sports Medicine. (It should be noted that along with a written description of the surgery, a video is available at the link—readers should be aware before viewing the video that parts of it are graphic.) Basically, during this procedure the quadrilateral/quadrangular space is enlarged by removing scarring, fascia, or other tissues impinging on the space. Dr. Hangge and his colleagues noted that this surgery is often quite successful at resolving symptoms.
Disclaimer
Please note that the information in this blog post is general in nature and is not meant to replace advice received from a medical professional. Those experiencing symptoms suspected of being related to QSS are encouraged to seek medical care.