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.

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.

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.

Shoulder Conditions

Thoracic Outlet Syndrome (TOS)

Get Clear, Concise Answers to Your Top Questions About Thoracic Outlet Syndrome (TOS)

Navigating a shoulder condition can be overwhelming. On this page, we've compiled the 15 most frequently asked questions about Thoracic Outlet Syndrome (TOS) to give you straightforward, expert-backed answers. Understand your symptoms, diagnosis, and what comes next with insights from Dr. Christian Veillette's practice. Plus, explore trusted external resources for even more information.

Thoracic Outlet Syndrome (TOS) is a condition that occurs when blood vessels or nerves in the space between your collarbone and your first rib (the "thoracic outlet") become compressed. This compression can lead to a variety of symptoms in your neck, shoulder, arm, and hand. This brochure will help you understand TOS, its treatment, and your recovery process.

Q1: What is Thoracic Outlet Syndrome (TOS)?

A: Thoracic Outlet Syndrome is a group of conditions that happen when there's pressure on the nerves or blood vessels (arteries and veins) in the space between your neck and shoulder, known as the thoracic outlet.

Q2: What causes TOS?

A: TOS can be caused by several factors, including:

Anatomical differences: Such as an extra rib (cervical rib) or abnormally tight fibrous bands.
Trauma: Injuries like car accidents can cause internal changes that lead to compression.
Poor posture: Drooping shoulders or holding your head forward can create pressure in the thoracic outlet.
Repetitive activities: Certain sports or occupations that involve repetitive arm and shoulder movements can contribute.

Q3: What are the common symptoms of TOS?

A: Symptoms vary depending on what is being compressed (nerves or blood vessels).

Nerve compression (Neurogenic TOS): Numbness, tingling, pain, or aching in the neck, shoulder, arm, or hand; weakening grip; sometimes changes in skin color when arms are raised.
Vein compression (Venous TOS): Swelling, redness, or a heavy feeling in the arm; bluish discoloration of the hand; blood clots in the veins of the upper body.
Artery compression (Arterial TOS): Cold fingers, hands, or arms; pain in the hand and arm; paleness or bluish discoloration of fingers or hand; weak or absent pulse in the affected arm.

Q4: How is TOS diagnosed?

A: Diagnosing TOS involves a thorough medical history, physical examination, and often imaging tests. Your doctor may ask you to perform certain arm or neck movements to reproduce your symptoms. Imaging tests can include:

X-rays
Ultrasound
CT scans
MRI scans
Arteriography or Venography (special X-rays using dye to visualize blood vessels)
Nerve conduction studies (to check nerve function)

Q5: What are the non-surgical treatment options for TOS?

A: Non-surgical treatments are often the first approach, especially for neurogenic TOS, and may include:

Physical Therapy: Exercises to improve posture, strengthen shoulder and neck muscles, and increase range of motion.
Medications: Over-the-counter pain relievers (like ibuprofen) or prescribed muscle relaxants and stronger pain medications to manage pain and inflammation.
Lifestyle Changes: Avoiding activities that worsen symptoms, maintaining good posture, and sometimes weight loss.

Q6: When is surgery considered for TOS?

A: Surgery is typically considered when non-surgical treatments haven't provided enough relief, or in cases of venous or arterial TOS, where there's a risk of blood clots or reduced blood flow.

Q7: What does TOS surgery involve? What are the goals and risks?

A: The most common surgery for TOS is thoracic outlet decompression, which aims to relieve pressure on the nerves and/or blood vessels. This often involves removing a portion of the first rib and sometimes some surrounding muscles (like the scalene muscles).

Goals: To create more space in the thoracic outlet, reduce compression, and relieve symptoms like pain, numbness, and weakness.
Risks: As with any surgery, risks can include nerve damage, infection, excessive bleeding, improper wound healing, and complications related to anesthesia. For vascular TOS, risks like blood clots or narrowing of the artery can also occur.

Q8: How do I prepare for TOS treatment or surgery?

A: Your doctor will give you specific instructions. This may include:

Undergoing additional imaging tests.
Following instructions on when to stop eating and drinking before surgery.
Adjusting current medications as advised by your doctor.
Planning for your hospital stay (typically 1-2 days if surgery is performed).

Q9: What can I expect immediately after TOS surgery?

A: You will be monitored closely. You may have an IV for fluids and medication, and possibly a chest tube if the lung was involved. Pain will be managed with medication. You'll be encouraged to start moving around as soon as possible and do breathing exercises to prevent complications like blood clots or pneumonia.

Q10: How long is the typical recovery period for TOS?

A: Recovery time varies based on the individual and the type of treatment.

Non-surgical: Improvement can take weeks to months.
Surgical: Light activity may resume in 7-10 days, with full recovery taking 3 to 6 months. It's crucial to follow your physical therapy plan for the best outcome.

Q11: What does rehabilitation/physical therapy involve after TOS treatment?

A: Physical therapy is a key part of recovery. It involves exercises to:

Restore range of motion in the shoulder and neck.
Strengthen muscles around the shoulder blade.
Improve posture.
Address tight muscles and structural limitations.
You will typically start with gentle movements and gradually progress to more advanced exercises.

Q12: How will pain be managed during recovery?

A: Your doctor will prescribe pain medication. This may include a combination of over-the-counter medications (like acetaminophen or ibuprofen) and stronger prescription pain relievers, sometimes including muscle relaxants. It's important to take your medication as directed to stay ahead of the pain, especially in the initial recovery period.

Q13: What can I do at home to help my recovery?

Follow all instructions: Adhere strictly to your doctor's and physical therapist's advice.
Medication adherence: Take your prescribed medications as directed.
Incision care (if surgical): Keep the incision clean and dry. Follow specific showering and wound care instructions.
Activity modification: Avoid heavy lifting and strenuous activities for several weeks as advised.
Posture and ergonomics: Maintain good posture and adjust your workspace to support it.
Temperature therapy: Heat can help relax stiff muscles, while ice can reduce swelling and pain.
Gentle stretching/exercises: Continue the exercises taught by your physical therapist.
Avoid activities that worsen symptoms: This includes carrying heavy bags on the affected shoulder or sustained overhead activities.
Proper sleep position: Avoid sleeping with arms extended overhead or on your stomach.

Q14: When can I expect to return to daily activities, work, driving, and sports?

A: This varies greatly depending on your individual recovery and the demands of your activities.

Daily activities: Light daily activities can usually be resumed within a few days to weeks.
Driving: Often permitted after your first clinic visit and once you are no longer taking opioid pain medication.
Work: Return to work depends on the physical demands of your job. Light duty may be possible sooner.
Sports: Return to sports will be a gradual process under the guidance of your physical therapist and doctor, often several months after surgery. Avoid contact sports and heavy lifting for a few weeks initially.

Q15: What signs or symptoms should I watch out for and report to my doctor immediately?

A: Contact your doctor right away if you experience any of the following:

Increased or uncontrolled pain
Fever or chills
Redness, excessive swelling, or discharge from your incision site
Sudden increase in arm or hand swelling, discoloration (blue or pale), or coldness
Severe numbness, tingling, or weakness that is new or worsening
Chest pain or shortness of breath

Long-Term Outlook:

The success rate of TOS treatment varies. Many people experience significant improvement in symptoms with physical therapy and other non-surgical approaches. If surgery is performed, success rates can vary, but many individuals find relief. Adhering to your rehabilitation plan is crucial for a positive long-term outcome. In some cases, symptoms may recur if underlying causes are not fully addressed or if proper rehabilitation is not followed.

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We encourage you to write down any specific questions you have and discuss them thoroughly with your surgeon, doctor, or physical therapist. They are your best resource for personalized advice and care.

Disclaimer: This brochure provides general information 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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