What is Quadrilateral Space Syndrome (QSS)?

Quadrilateral Space Syndrome (QSS) is a rare condition that occurs when the axillary nerve and/or the posterior circumflex humeral artery get squeezed or compressed as they pass through a small area in the back of your shoulder called the 'quadrilateral space.' This compression can lead to pain, numbness, tingling, and weakness in your arm.

QSS is often caused by repetitive overhead activities, common in athletes like throwers, swimmers, and tennis players. It can also result from repeated motions that narrow the space (overuse), extra bands of tissue that can form and compress the nerve or artery (fibrous bands), trauma or injury such as a shoulder dislocation or a direct blow to the shoulder which can cause swelling or scar tissue, or muscle enlargement if muscles in the area grow significantly (e.g., in bodybuilders), they can crowd the space.

What are the common symptoms of QSS?

Symptoms typically include vague pain or a dull ache in the back of the shoulder, sometimes radiating down the arm; numbness, tingling, or a 'pins and needles' sensation in the shoulder and upper arm; pain that worsens with overhead movements or when your arm is in a 'throwing' position; tenderness when pressure is applied over the back of the shoulder in the quadrilateral space; weakness or fatigue in the arm, especially when lifting or rotating it; and sometimes, shrinking (atrophy) of certain shoulder muscles like the teres minor or deltoid.

How is QSS diagnosed?

Diagnosing QSS can be challenging because its symptoms can be similar to other shoulder problems. Your doctor will ask about your symptoms, activities, and any past injuries; perform a physical examination to check your shoulder's range of motion, strength, sensation, and tenderness; may order imaging tests like MRI or ultrasound to look at the quadrilateral space, assess muscle size, and check for any abnormalities or scarring. In some cases, nerve conduction studies (NCS) or electromyography (EMG) might be performed to evaluate how well the axillary nerve is working. An injection of local anesthetic into the quadrilateral space that temporarily relieves your symptoms can also help confirm the diagnosis.

What are the non-surgical treatment options?

Most cases of QSS improve with non-surgical treatment. These options focus on reducing pressure on the nerve and artery, managing pain, and restoring function: rest and activity modification (avoiding or modifying activities that worsen your symptoms, especially overhead movements); anti-inflammatory medications (over-the-counter or prescription NSAIDs like ibuprofen can help reduce pain and inflammation); ice or heat packs (applying ice can help reduce pain and inflammation, especially after activity, heat can help relax muscles); physical therapy (a physical therapist will guide you through exercises to maintain or improve shoulder range of motion and flexibility, strengthen the muscles around your shoulder to provide better support, improve posture and body mechanics); and corticosteroid injections (in some cases, your doctor may suggest an injection of corticosteroid medication into the area to reduce inflammation and pain).

When is surgery considered for QSS?

Surgery is usually considered if non-surgical treatments haven't significantly improved your symptoms after about six weeks or more; symptoms are severe or progressively worsening; or there's clear evidence of nerve damage or significant compression.

What does the surgical procedure involve?

The goal of surgery, called decompression, is to relieve pressure on the axillary nerve and posterior circumflex humeral artery. This typically involves making a small incision at the back of your shoulder; identifying the compressed nerve and artery; carefully removing or cutting any fibrous bands, scar tissue, or other abnormal structures that are causing the compression. The procedure is designed to free up the nerve and artery, allowing them to function normally.

What are the potential risks of surgery?

As with any surgery, there are potential risks, though QSS surgery is generally safe. These can include infection, bleeding, damage to surrounding nerves or blood vessels, scarring, persistent pain or incomplete relief of symptoms, and reaction to anesthesia. Your surgeon will discuss these risks with you in detail.

What do I need to do before surgery?

Your healthcare team will provide specific instructions, but generally, you may need to undergo a pre-operative physical examination and blood tests; stop certain medications (e.g., blood thinners, some anti-inflammatory drugs) a week or two before surgery; arrange for someone to drive you home after surgery and help you during the first few days of recovery; and avoid eating or drinking for a certain period before the surgery.

What can I expect immediately after surgery?

You will likely have your arm in a sling to help it rest and heal. You may experience some pain, which will be managed with medication. Your surgical site will be covered with a dressing. Your surgeon will give you instructions on wound care and activity restrictions.

How long is the typical recovery period?

Recovery times vary for each person, depending on the severity of the condition and how long the nerve was compressed. First few weeks (0-2 weeks): Focus on rest, pain management, and protecting the surgical site. Gentle elbow and wrist movements will be encouraged. Weeks 2-6: You will start physical therapy, focusing on gentle range-of-motion exercises for your shoulder. After 6 weeks: As healing progresses, your physical therapist will introduce strengthening exercises to rebuild muscle strength. Overall, it can take several weeks to months to feel significant improvement, as nerve healing is a slow process.

What does rehabilitation/physical therapy involve?

Physical therapy is crucial for a successful recovery. Your therapist will design a personalized program that may include pain and swelling management (using ice, gentle massage, or other techniques); range of motion exercises (to restore full movement in your shoulder); strengthening exercises (targeting the muscles around your shoulder, including the deltoid and teres minor, which may have been weakened); postural correction (to improve overall shoulder mechanics); and activity-specific training (gradually reintroducing movements related to your work, sports, or daily activities).

How will pain be managed?

Your doctor will prescribe pain medication to help manage discomfort after surgery. This may include prescription pain relievers (e.g., opioids for a short period); over-the-counter pain relievers (e.g., acetaminophen, ibuprofen) as recommended by your doctor. You may also use ice packs to reduce localized pain and swelling.

When can I expect to return to daily activities, work, driving, and sports?

This timeline varies greatly based on your recovery progress and the demands of your activities. Daily activities: Light daily activities can usually be resumed within a few days to weeks. Driving: You can typically drive once you are no longer taking strong pain medications and have sufficient control and range of motion in your shoulder to safely operate a vehicle (often a few weeks after surgery). Work: Return to work depends on the nature of your job. Light, desk-based work might be possible within a few weeks, while jobs requiring heavy lifting or repetitive overhead movements will take longer, potentially several months. Sports: A gradual return to sports, especially overhead activities, will be guided by your physical therapist and surgeon, often not for several months after surgery. Full return to competitive sports may take 3-6 months or longer.

What is the expected long-term outcome?

For many patients, surgical decompression of QSS provides significant relief from pain, numbness, and weakness, allowing them to return to their normal activities, including sports. Nerve healing can be slow, so improvement may continue for several months. While some mild symptoms may occasionally linger, the goal is to significantly improve your quality of life and shoulder function.

Non-Operative Exercises

Periscapular Strengthening Exercises

Step-by-step home exercise guide for periscapular strengthening to prioritize the serratus anterior and lower trapezius, creating a stable base for an unstable joint.

Active rehabilitation is a cornerstone of recovery. On this page, we outline key home exercises for periscapular strengthening, prioritizing the serratus anterior and lower trapezius, to help you regain shoulder function. Always consult your care team before beginning.

Having a stable shoulder joint depends heavily on the muscles supporting your shoulder blade (scapula). The serratus anterior and lower trapezius function as the core stabilizers of the shoulder blade. Together, they act like an anchor, positioning the socket properly so the ball of your shoulder joint can move smoothly and securely. Strengthening these periscapular muscles creates a solid foundation, which is especially important if your shoulder joint feels unstable or loose.

General Guidelines & Safety Precautions

To perform these exercises safely and effectively, please follow these guidelines:

Warm-Up: Spend 3 to 5 minutes doing light activity like arm swings or shoulder shrugs to warm up the muscles.
Pain Rule: Exercises should feel challenging but not painful. If you feel sharp, pinching, or sudden pain in the shoulder, stop immediately. Mild muscle fatigue is normal.
Controlled Movements: Perform all exercises slowly and deliberately, focusing on the movement of your shoulder blades rather than just moving your arms.

The Exercise Program

Exercise 1: Wall Slides with Protraction

Purpose: Specifically targets the serratus anterior to help pull the shoulder blade forward and wrap it securely around the rib cage.

Equipment Needed: A foam roller or a small towel, and a smooth wall.

Starting Position: Stand facing the wall. Place your forearms against the wall at shoulder height, forming a 90-degree angle at your elbows. Place a foam roller or towel between your forearms and the wall.

Instructions:

Gently push your forearms into the wall to push your upper back away from the wall (this is protraction, separating your shoulder blades). Keep your neck relaxed.
Slowly slide your forearms up the wall in a V-shape, maintaining the gentle forward pressure.
Go as high as you can without letting your shoulders shrug up toward your ears or losing contact with the wall.
Slowly slide back down to the starting position.

Dosage: Perform 2 sets of 10 repetitions, once daily.

Tips to Avoid: Avoid arching your lower back or letting your chest sag toward the wall. Keep your core tight and your shoulders down.

Exercise 2: Prone Y-Raises

Purpose: Focuses on strengthening the lower trapezius, which is essential for rotating the shoulder blade upward and stabilizing the joint.

Equipment Needed: A sturdy table, bed, or a comfortable exercise mat on the floor.

Starting Position: Lie face down on your stomach. If using a bed, you can let your head rest comfortably. Extend your arms out at a 45-degree angle from your body, forming the shape of a \"Y\". Point your thumbs up toward the ceiling.

Instructions:

Tuck your chin slightly to keep your neck in a neutral, comfortable position.
Squeeze your shoulder blades down and together (think about tucking your shoulder blades into your back pockets).
Slowly raise your arms off the bed or floor. Keep your elbows straight.
Hold the raised position for 2 seconds, then slowly lower your arms back down.

Dosage: Perform 3 sets of 8 repetitions, once daily.

Tips to Avoid: Do not shrug your shoulders up to your ears. If lifting the arms is too difficult, start by just lifting your thumbs slightly or squeezing the shoulder blades first.

Exercise 3: Scapular Punches

Purpose: Strengthens the serratus anterior muscle through isolated forward movement of the shoulder blade.

Equipment Needed: A comfortable exercise mat.

Starting Position: Lie flat on your back on the mat. Extend both arms straight up toward the ceiling, keeping your hands in line with your shoulders and your elbows fully straight.

Instructions:

Without bending your elbows, reach your hands higher toward the ceiling, lifting your shoulder blades off the floor.
Hold this reached or \"punched\" position for 2 seconds.
Slowly lower your shoulders back down, letting your shoulder blades press flat against the floor again. Keep your arms straight throughout.

Dosage: Perform 2 sets of 12 repetitions, once daily.

Tips to Avoid: Avoid bending your elbows or using your neck muscles to lift your head. The movement should come solely from your shoulder blades sliding forward and backward.

Exercise 4: Resisted Band Rows with Depression

Purpose: Activates the lower trapezius and rhomboids to pull the shoulder blades down and back, creating a stable platform for the shoulder.

Equipment Needed: A resistance band secured at chest height to a sturdy anchor (like a door anchor).

Starting Position: Stand facing the anchor point. Hold the ends of the resistance band in each hand with your arms extended forward. Step back until you feel light tension in the band.

Instructions:

Stand tall with your feet shoulder-width apart and your knees slightly bent.
Pull your elbows back toward your sides, squeezing your shoulder blades together.
As you pull, actively focus on drawing your shoulder blades downward, away from your ears.
Slowly return your arms to the starting position under control.

Dosage: Perform 3 sets of 10 repetitions, once daily.

Tips to Avoid: Do not lean backward to pull the band. Keep your trunk upright and engage your abdominal muscles. Do not let your shoulders roll forward at the end of the movement.

Always consult with your physical therapist or doctor before starting a new exercise routine. If any exercise causes persistent pain or swelling, discontinue it and contact your healthcare provider.

Disclaimer: This guide provides general exercise instructions and is not a substitute for professional medical advice. Always consult your doctor or qualified healthcare provider with any questions you may have regarding your specific medical condition and treatment plan.

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