Thoracic outlet syndrome is a condition of compression involving the brachial plexus and subclavian vessels. Although there are multiple surgical approaches to address thoracic outlet decompression, supraclavicular first rib resection with scalenectomy and brachial plexus neurolysis allow for complete exposure of the first rib, brachial plexus, and vasculature. This technique is described in detail. This approach is safe and can produce excellent outcomes in all variants of thoracic outlet syndrome.
Key points
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Thoracic outlet syndrome is a condition of compression of the brachial plexus and/or subclavian vessels as they traverse the thorax to the upper extremity.
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A supraclavicular approach to first rib resection with scalenectomy and brachial plexus neurolysis gives the surgeon excellent exposure of the entire first rib, brachial plexus trunks, and subclavian vessels.
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Results from this approach show an excellent to good response in more than 80% of patients who are selected carefully for operation.
Introduction/history/definitions/background
Thoracic outlet syndrome (TOS) continues to be a difficult problem that thoracic surgeons may encounter. Although arterial and venous variants of TOS may be more straightforward to diagnose and treat, neurogenic TOS (NTOS) remains the most common variant and most difficult to diagnose, given no clinical testing has been shown to confirm the diagnosis. Many terms predated the term TOS, including cervical rib syndrome, scalene anticus syndrome, costoclavicular syndrome, and hyperabduction syndrome, because the disease process has attempted to be described by many giants in the field for more than 200 years.
Surgical approaches to address this disease started in the 1800s in London where Mr Holmes Coot excised a cervical rib in a 26-year-old woman with a painful, pulsatile supraclavicular mass. In 1920, Stopford and Telford reported on a group of patients who presented with loss of grip strength, fatigue of the hand with exercise, and weakness of the intrinsic muscles of the hand. They excised the impinging portion of the first rib and noted rapid resolution of the vasomotor and sensory changes with slow resolution of the motor changes as well. The 1930s saw Naffziger and Ochsner show the benefit of anterior scalenectomy for patients with “scalenus syndrome.” David Roos described a series of patients in 1966 who underwent transaxillary removal of the first rib with good outcomes and technical reproducibility. This paved the way for the transaxillary approach to be the standard for first rib resection into the 1970s and 1980s. Supraclavicular first rib resection was not described until 1985, when Sanders described the technique with the addition of scalenectomy and Reilly in 1988.
Although there are a growing number of approaches to address first rib resection for TOS, the authors favor the supraclavicular approach compared with the transaxillary, infraclavicular, and minimally invasive (robotic/video-assisted thoracic surgery) operations. The supraclavicular approach is the most versatile and can address all 3 variants of TOS due to the following advantages :
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A greater amount of the anterior and middle scalene muscles can be removed.
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It provides complete exposure of the entire rib from the costochondral cartilage to the head of the rib.
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The spinal nerves and trunks of the branchial plexus can be fully exposed and a more extensive neurolysis can be achieved.
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It allows for exposure of cervical ribs, elongated C7 transverse process, and anomalies of the scalene muscles from the same field.
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Vascular repair/reconstruction of the subclavian artery and vein can be performed.
It is the authors’ belief, and the belief of many investigators in this field, that for the best patient results, the first rib should be resected from the costochondral cartilage to head of the rib medial to the T1 spinal nerve along with portions of both anterior and middle scalene muscles and all fibrous scar tissue around the brachial plexus trunks and spinal nerves. The following text describes the authors’ surgical approach.
Anatomy
The borders of the thoracic outlet are bound by 3 bony structures: the spinal column (medially), the first rib (inferiorly), and the clavicle (anteriorly). The cervicoaxillary canal, which traverses this area, houses the subclavian vessels and brachial plexus and can be divided into 2 sections. The proximal section contains the scalene triangle and costoclavicular space whereas the distal section is composed of the axilla and contains the subcoracoid space under the pectoralis minor muscle. The scalene triangle is composed of the anterior scalene muscle anteriorly and the middle scalene posteriorly with the first rib forming the base of the triangle. This space commonly is involved in TOS and a common site of brachial plexus compression. The anterior scalene muscle originates from the third through sixth cervical vertebrae transverse processes. It inserts onto the anterior/superior border of the first rib at a tubercle. The middle scalene muscle arises from the transverse processes of the second through seventh cervical vertebrae and inserts widely on the posterolateral portion of the first rib. The trunks of the brachial plexus travel through this triangle along with the subclavian artery. The second part of the proximal space is the costoclavicular space. This area makes up the space between the first rib and clavicle. Both subclavian artery and vein pass through this space along with the brachial plexus. The distal axilla section is bound by the pectoralis minor muscle anteriorly, the coracoid process of the scapula superiorly, and the chest wall posteriorly. Both axillary artery and vein along with the cords of the brachial plexus traverse this space.
Functional anatomy is important to consider when evaluating patients for possible TOS. Narrowing of the costoclavicular area occurs during abduction of the arm due to clavicle rotating back toward the first rib and anterior scalene muscle insertion. Hyperabduction can cause the coracoid process to tilt downward near the insertion of the pectoralis minor muscle, which exaggerates the tension on the neurovascular bundle. Simple drooping of the shoulders (decreasing the angle of the sternoclavicular joint, normally 15°–20°) may narrow the costoclavicular space, also putting compression on the neurovascular structures. It is important for the surgeon to consider these anatomic and functional considerations when evaluating a patient for thoracic outlet decompression.
Nature of the problem/diagnosis
TOS is a condition of compression. The etiology of this compression can come in many forms and compress different structures, thereby leading to the different types of TOS (arterial, venous, and neurogenic). Congenital sources of compression commonly arise from anatomic variants in bony and muscular structures (cervical ribs, supernumerary or fused scalene muscles, muscle hypertrophy, and cervical fibrocartilaginous bands). Acquired causes of compression also are common in the form of injury/trauma. This also can present in the setting of repetitive movements (overhead arm movements and neck movements) related to occupational or athletic environments (pitching and swimming).
Although the presentation and evaluation of patients with TOS are discussed elsewhere in this edition, diagnostic testing can be negative or equivocal in the evaluation of NTOS. A thorough history and physical examination are critically important to understand the background of a patient’s symptoms and evaluating sensory/motor deficits. The reproduction of symptoms with neck and/or upper extremity positional testing is a common finding. This also allows the surgeon to evaluate for potential cervical spine or shoulder pathology, which should be ruled out prior to a suspected diagnosis of NTOS.
A multitude of diagnostic testing can be done for NTOS, but no 1 modality is able to confirm the clinical diagnosis. Electrodiagnostic testing can be specific for a diagnosis of NTOS, but this study can be operator dependent and is negative in many NTOS patients. Upper extremity vascular studies may be helpful when evaluating patients with suspected vascular TOS, but its role is unverified when NTOS is suspected. Imaging studies used to evaluate TOS include ultrasound, computed tomography, magnetic resonance, and conventional angiography, depending the type of TOS suspected. For NTOS, the authors prefer computed tomography with specific TOS protocol (with intravenous [IV] contrast) to evaluate bony structures, surrounding muscle, and vascular compression. The authors also advocate for the preoperative use of botulinum toxin A injection of the anterior scalene and pectoralis muscle as a diagnostic and therapeutic procedure. A recent study from the Massachusetts General Hospital evaluated 157 patients who underwent preoperative botulinum toxin A injection and found a statistically significant correlation of improvement of symptoms postinjection to improvement of symptoms postoperatively after first rib resection with scalenectomy and brachial plexus neurolysis.
Preoperative/preprocedure planning
Once a decision has been made to operate on a patient, all imaging should be reviewed prior to the patient coming to the operating room. The authors’ preference for imaging is computed tomographic scan with specific thoracic outlet protocol and 3-dimensional reconstructions. It is important to review anatomic landmarks and review for aberrant anatomy, including bone and vascular anatomy.
It is the authors’ preference to instruct all patients the night before the operation to eat a meal with a high fat content. They find this aids in identifying lymphatic vessels during dissection and ligation if chyle leak is noted. This is more critical for a left-sided operation but also may be used for a right-sided approach.
A detailed discussion regarding the case should be held with the anesthesia provider. General anesthesia and single-lumen endotracheal are used, but long-acting neuromuscular blocking agents should be avoided. If needed, a short-acting agent can be used at the time of induction but should not be redosed during the case. One or 2 large-bore IV lines are adequate for the case and central access typically is not necessary. Arterial line use rarely is needed but can be considered given comorbidities of the patient and an individual basis. If used, it should be placed on opposite arm of the operative side.
Preparation and patient positioning
The patient’s head should be well supported with a low-profile pillow or cushion. The authors find the gel doughnut to work well in this situation. The head should be slightly turned 45° away from the operative side. Too much rotation of the head may distort landmarks in the surgical field. The arms should be tucked and padded around the elbow and wrist. Special care should be taken to not distort IV tubing, the blood pressure cuff, or arterial line tubing (if present). The hands and wrist should be in a neutral thumbs-up position. The authors recommend rolling blue surgical towels to simulate an aluminum can and place this in the patient’s hand for support. A stack of folded surgical towels then is used to elevate the shoulder on the surgical side. The number of towels is enough to support the shoulder, raising it off the bed and opening the costoclavicular space. The operating room bed should then be placed in a semi-Fowler position. The back of the patient should be in an approximately 30° incline with the legs flat or with a slight decline to relive tension on the lower back ( Fig. 1 ).
The patient should be prepped from the chin, including both sides of the neck, shoulder to shoulder, and down to the umbilicus. Standard surgical drapes then are used (U drape may be preferred from bottom up) such that there is access to the neck on the surgical side, supraclavicular area to the shoulder, and down to the umbilicus. Although it is extremely rare to need access to the sternum, the patient should be prepped and ready for sternotomy, if needed. A sterile blue towel is used to cover the chest and protect the patient’s skin. The surgical drapes passed to the anesthesia team should be attached to the IV pole or ether screen in a low profile to allow the surgeon and assistant to look from a cephalad to caudal direction in the surgical field.
Procedural approach
The skin incision is typically 4 cm to 5 cm long (range 3.5–6 cm) and is centered on the lateral border of the sternocleidomastoid (SCM) muscle. This incision is placed 1 cm to 2 cm above the clavicle. The electrocautery then is used ed to divide the subcutaneous tissue and platysma. Skin hooks then are used to create subplatysmal flaps for 2 cm to 3 cm in all directions of the incision ( Fig. 2 ).
