Quadrilateral Space Syndrome - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Quadrilateral space syndrome is a rare condition due to compression of the nerves and arteries present in the quadrilateral space (present in the upper arm), causing many symptoms like weakness, pain, or limited range of motion. Although not as well-known as other nerve compression syndromes, such as carpal tunnel syndrome (a condition where the nerve in the wrist called the median nerve gets compressed, leading to numbness or weakness in the fingers and hands), QSS can significantly impact a person's quality of life. This article will delve into the intricacies of quadrilateral space syndrome, exploring its causes, symptoms, diagnosis, and potential treatment options.

Who First Coined the Term Quadrilateral Space Syndrome?

It was first coined by Cahill in 1980. Later, a baseball player complained about partial blockage to his finger, which occurred because of an injury to the artery present in the quadrilateral space, which gained further recognition. These types of cases have then been reported mostly among the throwing athletes (swimming, volleyball, or basketball). This syndrome is also reported while cleaning the windows. According to Cahill, four major features include:

• Presence of diffuse pain in the shoulder.

• Paresthesia in a scattered manner.

• Above the quadrilateral space, there is the presence of point tenderness.

• Positive angiogram when the hand is placed in specific positions.

What Is Quadrilateral Space Syndrome?

The quadrilateral space is a small anatomical region located in the shoulder area. It is bounded by four structures - the teres minor muscle, the teres major muscle, the long head of the triceps, and the humerus bone. Within this confined space runs the axillary nerve, which supplies sensation and motor function to the shoulder joint and the skin over the deltoid muscle. An artery called the posterior humeral circumflex artery (PHCA) also passes through this space, which supplies blood to the deltoid, teres major, teres minor, head of humerus, and triceps muscle.

Quadrilateral space syndrome occurs when the axillary nerve and/or the posterior humeral circumflex artery become compressed or entrapped within this quadrilateral space. The compression can be caused by various factors, such as trauma, repetitive motion, inflammation, or anatomical abnormalities. The exact cause of QSS is not always identifiable, making diagnosis and management challenging.

What Are the Causes of Quadrilateral Space Syndrome?

• Compression or irritation of the axillary nerve.

• Trauma or injury to the quadrilateral space region.

• Overuse or repetitive motion of the shoulder and arm.

• Anatomical variations or abnormalities in the structures within the quadrilateral space.

• Space-occupying lesions or masses, such as cysts (labral cysts), hematomas (localized collections of blood outside of blood vessels), or tumors, are in the vicinity of the quadrilateral space.

• Muscular hypertrophy or hypertonicity in the adjacent shoulder muscles.

• Nerve entrapment or impingement due to inflammation or fibrous bands in the region.

• Rarely, it can be a complication of thoracic surgery.

What Are the Symptoms of Quadrilateral Space Syndrome?

It usually affects young people who are less than 40 years old and present with a history of repeated overhead activities.

Neurogenic Symptoms:

• Shoulder Pain: This is the most common symptom. The pain is often deep and aching, and it may be localized to the back of the shoulder or upper arm. Patients may have difficulty pinpointing the exact location of the pain.

• Muscle Weakness: Due to nerve compression, weakness in the shoulder muscles can occur. The deltoid muscle and rotator cuff muscles may be affected, leading to difficulty in lifting or moving the arm properly.

• Numbness or Tingling: Nerve compression can cause sensory disturbances like numbness or tingling, which is called paresthesia in the shoulder, upper arm, or back of the arm. In some cases, patients may also experience altered sensations that extend down the arm toward the hand.

• Limited Range of Motion: Because of the compression of the nerve in the quadrilateral space, can cause limited joint mobility. This can cause challenges in performing daily activities.

• Muscle Atrophy: Wasting of muscles may develop.

• Exacerbated Pain with Movements: Certain shoulder movements or activities can worsen the pain in QSS. Actions like lifting heavy objects, repetitive overhead motions, or positions that compress the quadrilateral space may trigger or aggravate the symptoms.

• Fasciculation: Involuntary muscle twitches.

Vascular Symptoms: These may not be frequently reported.

• Thrombosis: A blood clot in the blood vessel.

• Microembolism or Macroembolism: A blood clot that blocks the blood flow in the blood vessel. This can cause bluish discoloration of affected fingers.

• Hand or Digital Ischemia: Reduced flow of blood to the hand, toes, or finger.

• Symptoms of Acute Ischemia: These include absent pulses, pallor, and pain.

How to Diagnose Quadrilateral Space Syndrome?

• Medical History and Physical Examination: The doctor will begin by taking a detailed medical history, including any symptoms the person is experiencing, how and when they started, and any relevant past medical conditions or injuries. They will then conduct a physical examination, assessing the shoulder's range of motion and strength and looking for any specific signs that may suggest QSS.

• Clinical Tests: There are specific clinical tests that can help in assessing nerve and vascular compression in the shoulder. The "Quadrilateral Space Compression Test" is one such test. During this test, the doctor will exert pressure on the quadrilateral space while maneuvering the arm into specific positions to determine if it elicits the same symptoms that the person has been experiencing.

• Imaging Studies: Imaging studies can help rule out other conditions and visualize any structural abnormalities. MRI (magnetic resonance imaging) may be ordered to assess soft tissues, muscles (atrophy of teres minor muscle), and nerves in the shoulder area. Other imaging studies include digital subtraction angiography, magnetic resonance angiography, and computed tomography angiography which can show PHCA occlusion. Another test, called arteriography, can show compression of the artery when the arm is lifted and rotated outward.

• Electromyography (EMG) and Nerve Conduction Studies: These tests can help evaluate the electrical activity of muscles and the function of nerves. EMG can detect nerve damage or compression and determine if the axillary nerve is affected in QSS.

• Angiography: Angiography may be used to assess the blood flow in the posterior humeral circumflex artery, which could be compressed in QSS.

• Differential Diagnosis: The doctor needs to rule out other conditions that may present with similar symptoms, such as rotator cuff injuries, cervical spine pathology, labral injuries, impingement syndrome, or brachial plexus pathologies.

How Can Quadrilateral Space Syndrome Be Managed?

1. Conservative Treatment:

• Rest: Avoid activities that worsen the symptoms to allow the affected area to heal.

• Physical Therapy: The recommended approach includes massages, engaging in shoulder muscle strengthening exercises, and performing a range of motion exercises to enhance mobility, alleviate discomfort, and minimize pain.

• Pain Management: Non-steroidal anti-inflammatory drugs (NSAIDs) or other pain-relieving medications may be prescribed to alleviate pain and inflammation.

2.Corticosteroid Injections:

• If conservative treatment does not provide sufficient relief, corticosteroid injections may be considered to reduce inflammation and alleviate symptoms temporarily. These injections are given under the guidance of ultrasound. Relief of symptoms like tingling or coldness after these injections or local anesthesia can be a diagnostic sign of quadrilateral space syndrome.

3. Surgical Intervention: This is carried out when patients do not get relieved from conservative treatments for at least six months.

• If conservative treatments fail to relieve the symptoms or if there is significant nerve or vessel compression, surgery may be necessary to release the structures in the quadrilateral space.

• During the surgical procedure, the surgeon will alleviate compression of the axillary nerve and the posterior circumflex humeral artery by releasing the structures responsible for the compression.

• Following the surgery, an arm sling is placed, and physical therapy might be advised to facilitate the recovery and rehabilitation process.

Other treatments include breaking clots, such as thrombolysis and thrombectomy. Another treatment called aneurysm resection (a weak section of the artery is removed) can be considered. In rare cases, this may resolve on its own.

Conclusion:

Quadrilateral space syndrome, a disorder affecting the upper arm can cause many symptoms. Because the symptoms are very vague, a delay in the diagnosis may occur. Therefore, healthcare professionals should be aware of this condition, along with its differential diagnosis. Accurate diagnosis can help the patient live a healthy life and can prevent complications.