T4 Syndrome

 

Clinically Relevant Anatomy

In1997 Evans described the basic science behind the origins of T4 syndrome¹. Vasomotor nerve fibers descend in the spinal cord and emerge in the ventral horns and roots. These fibers pass the dorsal root ganglia as it sits in the invertebral foramen. Next they emerge as part of a spinal segmental nerve. Sympathetic fibers leave the segmental nerve and join the sympathetic chain. The sympathetic chain travels down the necks of the ribs with variable areas of ganglia (Greek word “ganglion” meaning “lump”). Branches from the sympathetic chain pass over the costovertebral joints to supply the heart, esophagus, and abdominal viscera. It is not uncommon for these branches to become stretched or affected by neighboring osteophytes. The sympathetic chain fibers ascend or descend a variable number of segments, synapse in a ganglion, and leave the chain to join a peripheral nerve. 

Sympathetic fibers can pass distally leaving the peripheral nerve to join an artery in the neurovascular bundle. Here they assist with the control of blood pressure via vasoconstriction. Sympathetic fibers are motor but do contain afferent filaments which synapse in the dorsal root ganglion and enter the spinal cord with somatic afferents.

It is thought that the head and neck are provided with sympathetic outflow from T1 to T4. The upper trunk and extremities are thought to be supplied by T2 to T5. Symptoms in the neck, head, and upper extremities are believed to be due to any of the following:

• Entrapment of segmental spinal nerves which carry sympathetic afferents
• Entrapment or ischemia of sympathetic nerves over rib necks or osteohpytes
• Referred pain from the heart, esophagus, or abdominal viscera
• Referred pain from a thoracic spinal structure
• Referred pain in the neck from a dorsal spinal structure
• Referred pain from any structure in the upper quarter
  
  

Mechanism of Injury / Pathological Process

The exact mechanism of T4 syndrome is unclear but it is hypothesized that sustained or extreme postures can lead to relative ischemia within multiple tissues contributing to symptoms of sympathetic origin¹. Symptoms originating from the sympathetic nervous system are distinctly different from somatic referred symptoms. The sympathetic nervous system provides pathways for referral of symptoms from the thoracic spine to the head and upper extremities. Symptoms may not be derived solely from the fourth thoracic vertebra, but also other upper thoracic vertebra^1,4. Hence “T4 syndrome” may also be referred to as “upper thoracic syndrome”.

Clinical Presentation

Patients presenting with T4 syndrome are typically between 30 to 50 years of age^1-2. The condition occurs more frequently in women by a 4:1 ratio². Symptom onset may coincide with a new job or hobby, especially those that require frequent stooping or bending (electricians, surgeons, and assembly-line worker’s). Frequent posturing in front of computer has also been implicated. Symptoms are often diffuse and located in the neck, head, and upper extremities (unilateral or bilateral)1-4.

Upper extremity paraesthesia and pain with or without neck and/or head pain^1-4:

• Paraesthesias in all five digits, or whole hand, or forearm-hand (glove-like distribution)
• Hands feel hot or cold
• Heaviness in upper extremities
• Hands feel and may objectively be swollen
• Non-dermatomal aches/pains in arm and/or forearm
• Pain often described as crushing or like a tight band

Less common symptoms could include^1-2:

• Pain and/or stiffness radiating around chest wall
• Interscapular pain and/or stiffness
• Worse pain at night often waking from sleep
• Creepy-crawly feelings or sensations of gushing water in arm
• Normal UE sensory, motor, reflex testing

Objective signs commonly include^1-4:

• Upper thoracic segmental mobility assessment commonly hypomobile and may reproduce or eliminate symptoms
• Palpation of rib angles may elicit distal symptoms
• Positive neural tension signs in the involved upper extremties
• Forward head posture and/or possible flat thoracic spine
• Cervical and trunk AROM may be pain free
• Hands may appear discolored (red or purple) and feel hot or cold to touch
  

Diagnostic Procedures

There are no validated clinical criteria to assist in diagnosing T4 syndrome. Also, radiographs do not aid in the diagnosis, however they may help rule out other conditions².

Outcome Measures

No self-report outcome measure has been validated for this specific condition. Any number of outcome measures would be appropriate for this patient population. This includes the Patient Specific Functional Scale (PSFS), Neck Disability Index (NDI), and Quick DASH

Management / Interventions

• Thoracic spine and rib cage (costovertebral and costotransverse joints) mobilization/manipulation^2-3
• Cervical spine mobilization/manipulation³
• Soft tissue mobilization to hypertonic musculature in cervicothoracic region²
• Self-mobilization techniques to the upper thoracic spine³
• Postural exercise and education^2-3
• Strengthening of the scapulothoracic musculature³
• Stretching tight pectoral and other upper quarter musculature³
  

Differential Diagnosis

Symptoms of T4 Syndrome can be confused with carpal tunnel syndrome, myofacial pain syndromes, cervical spine degenerative conditions, thoracic outlet syndrome, cardiac pain and pain originating from the viscera^1-4. Signs and symptoms of cardiac pain include the following²:

• Early mild symptoms include pain in region of the left breast/sternum; and tingling down the left arm into the hand.
• Feelings of a crushing tight band around the chest wall
• Pain radiating down the left arm (uncommonly the right), up the left side of the neck, into the throat and possibly to left half of the tongue.
• Symptoms worsen with exertion (especially in cold weather) and ease with rest.

Key Evidence

Several case studies have been reported in the literature^2-4. No validated diagnostic criteria have been established for T4 Syndrome. No randomized controlled trials have examined the most efficacious intervention strategies.

References

1. Evans P. The T4: syndrome some basic science aspects. Physiotherapy 1997;83(4):186-189.
2. DeFranca CG, Levine LJ. The T4 syndrome. J Manipulative Physiol Ther 1995;18(1):34–7.
3. Conroy JL, Schneiders AG. The T4 syndrome. Manual Therapy 2005;10:292-296.
4. Mellick GA, Mellick LB. Clinical presentation, quantitative sensory testing, and therapy of 2 patients with fourth thoracic syndrome. J Manipulative Physiol Ther 2006;29:403-408.