Robert W. Thompson and Chandu Vemuri
INDICATIONS/CONTRAINDICATIONS
Thoracic outlet syndrome (TOS) is a group of relatively uncommon, anatomically related, conditions caused by compression of neurovascular structures that serve the upper extremity. The most frequent form is neurogenic TOS (NTOS), which occurs in 85% to 90% of patients, most typically between the ages of 15 and 40. NTOS is characterized by symptoms arising from extrinsic compression and irritation of the brachial plexus nerves within the supraclavicular scalene triangle or within the infraclavicular subcoracoid space beneath the pectoralis minor muscle tendon (Fig. 10.1). NTOS results in neck and upper extremity pain, paresthesias, and functional limitations. Clinical recognition and appropriate treatment of NTOS are crucial to prevent disability in young active individuals (Table 10.1).
NTOS is caused by a combination of two factors: Predisposing anatomical variations and previous neck or upper extremity injury. The anatomical variations that may predispose to NTOS include anomalous scalene musculature, aberrant fibrofascial bands, and/or cervical ribs. Injury superimposed on this anatomical area can subsequently result in scalene/pectoralis muscle spasm, fibrosis, and other pathologic changes, which in turn lead to compression and irritation of the adjacent brachial plexus nerves. While the types of injury precipitating NTOS can include a motor vehicle collision with whiplash-type cervical strain or a fall on the outstretched arm, NTOS can also arise as a consequence of repetitive strain associated with frequent heavy lifting, poor posture, overhead use of the arm, or prolonged work at a computer keyboard. Although the presence of a cervical rib is often considered a prerequisite to the development of NTOS, only a small proportion of patients (approximately 10%) exhibit a definable cervical rib on radiographic studies, and in the absence of some form of additional injury, development of symptoms of NTOS remains rare even in patients with cervical ribs.
Figure 10.1 Anatomy of the thoracic outlet, with emphasis on the supraclavicular scalene triangle and the infraclavicular subcoracoid space.
Other forms of TOS include compression of the subclavian vein (venous TOS), most often presenting with the axillary–subclavian vein “effort thrombosis” (Paget–Schroetter) syndrome. This condition is readily differentiated from NTOS, as it results in marked arm swelling, cyanotic discoloration, and distention of subcutaneous veins around the shoulder and chest wall and is not usually associated with pain and paresthesia. The least frequent form of TOS arises from compression of the subclavian artery with pathologic changes (arterial TOS), usually in patients with a bony anatomical anomaly (e.g., cervical rib). Arterial TOS can result in fixed subclavian artery obstruction, resulting in cramping muscular fatigue with arm use similar to intermittent claudication. More frequently, it leads to poststenotic subclavian artery aneurysm formation and thromboembolism, hand ischemia, rest pain, and/or digital ulceration and necrosis. This clinical presentation is also readily differentiated from that of NTOS. It is important to recognize that positional compression of the subclavian artery during elevation of the arm is a frequent finding on physical examination in a substantial number of asymptomatic individuals and should not be considered evidence for arterial TOS in the absence of established arterial pathology.
TABLE 10.1 Differential Diagnosis of NTOS
Surgical treatment for NTOS can be accomplished effectively by several different approaches, including transaxillary first rib resection and anterior (supraclavicular) decompression, with each approach having its advantages and disadvantages. Supraclavicular decompression for NTOS most frequently involves complete anterior and middle scalenectomy, first rib resection, and brachial plexus neurolysis. This operation provides superb surgical exposure, a high degree of safety in experienced hands, and the most definitive means to address the relevant neurovascular structures, as well as flexibility in managing the entire spectrum of circumstances that may be encountered.
Supraclavicular decompression is a recommended treatment option for NTOS when the clinical diagnosis is considered to be sound and the patient has had substantial disability, with symptoms that interfere with daily activities and/or work. A third criterion for surgical treatment is that the patient has had an insufficient response to a course of physical therapy that has been appropriately targeted toward NTOS. Use of the supraclavicular approach to thoracic outlet decompression is also recommended when there has been no response to appropriate conservative measures in patients with persistent or recurrent symptoms of NTOS following a previous operation.1
For individuals with symptoms of disabling NTOS that are referable on physical examination to the subcoracoid space, the inclusion of pectoralis minor tenotomy is an important consideration as part of supraclavicular thoracic outlet decompression. In patients with NTOS in whom nerve compression symptoms appear confined to the subcoracoid space, pectoralis minor tenotomy may be performed as an isolated procedure.
PREOPERATIVE PLANNING
In the preoperative holding area, the supraclavicular surgical site is confirmed and marked. The subcoracoid space is included if concomitant pectoralis minor tenotomy is planned. Prophylactic antibiotics are administered within an hour of the planned procedure.
SURGERY
Positioning
After general endotracheal anesthesia is induced, the patient is positioned supine with the head of the operating table elevated approximately 30 degrees. The neck is extended and turned to the opposite side, and a small inflatable pillow is placed behind the shoulders. The neck, chest, and affected upper extremity are prepped into the sterile field, and the arm is wrapped in stockinette to permit free range of movement during the operation (Fig. 10.2). Lower extremity sequential compression devices are placed for prophylaxis against thromboembolism.
Incision
A transverse neck incision is made parallel to and just above the clavicle. This begins at the lateral edge of the sternocleidomastoid muscle and extends to the anterior edge of the trapezius muscle. The incision is carried through the subcutaneous layer and the platysma muscle is divided, then subplatysmal flaps are developed to expose the scalene fat pad. The sternocleidomastoid muscle is retracted medially, but it is not divided (Fig. 10.3).
Figure 10.2 Patient position and planned incisions for left-sided supraclavicular thoracic outlet decompression with pectoralis minor tenotomy.
Figure 10.3 The skin incision is made just above and parallel to the clavicle, extending from the lateral border of the sternocleidomastoid muscle to the anterior border of the trapezius muscle (A). Subplatysmal flaps are created to expose the underlying scalene fat pad (B). The scalene fat pad is mobilized, beginning with its medial attachments to the internal jugular vein (IJV) (C), and the omohyoid muscle is divided (D).
Mobilization of the Scalene Fat Pad
One of the keys to simplifying the supraclavicular exposure is proper mobilization and lateral reflection of the scalene fat pad.
The scalene fat pad is initially detached with the electrocautery along the lateral edge of the internal jugular vein and along the superior edge of the clavicle, while ligating small blood vessels and lymphatics. The omohyoid muscle is routinely divided. The thoracic duct is usually identified near the junction of the internal jugular and subclavian veins (this is more prominent on the left side, but a prominent accessory thoracic duct may also be found on the right side), and it may be ligated and divided (Fig. 10.3).
Using gentle fingertip dissection, the scalene fat pad is progressively elevated by moving in a medial to lateral direction, over the surface of the anterior scalene muscle. The phrenic nerve is identified as it descends along the muscle surface, passing in a lateral to medial direction, with a “dartle” (diaphragmatic startle) response elicited by gentle manipulation.
With further lateral mobilization of the scalene fat pad, the brachial plexus nerve roots (posterior and lateral to the anterior scalene muscle), and the middle scalene muscle (behind the brachial plexus) are gradually brought into view. The lateral aspect of the first rib may also be palpated and visualized at this stage. The long thoracic nerve is observed where it emerges from the body of the middle scalene muscle and passes beyond the lateral part of the first rib. The mobilized scalene fat pad is then held in position with several silk retraction sutures. The exposure is further maintained with a Henley self-retaining retractor, using the third arm to hold the edge of the sternocleidomastoid muscle. This exposure represents the first and most important of six “critical views” that should be obtained during supraclavicular decompression (Table 10.2) (Fig. 10.4).
Anterior Scalenectomy
Attention is next turned to detachment of the anterior scalene muscle from its insertion on the top of the first rib and subsequent resection of the muscle up to the apex of the scalene triangle.
The lower lateral edge of the anterior scalene muscle is dissected where it attaches to the first rib. The subclavian artery and brachial plexus are carefully mobilized away from the muscle, until a fingertip can be easily passed behind the muscle just above the first rib to displace the neurovascular structures posterolaterally. Blunt fingertip dissection is then continued in front of and behind the muscle to its medial edge, taking care to avoid the phrenic nerve by gentle medial retraction. Once the insertion of the anterior scalene muscle onto the top of the first rib has been completely isolated under direct vision, it is sharply divided from the top of the bone with scissors (Fig. 10.5).
TABLE 10.2 Critical Views Obtained During Supraclavicular Thoracic Outlet Decompression
Figure 10.4 Following lateral reflection of the scalene fat pad, direct visualization is obtained of the internal jugular vein (IJV), anterior scalene muscle (ASM), phrenic nerve (PhN), brachial plexus (BP), subclavian artery (SCA), middle scalene muscle (MSM), and long thoracic nerve (LTN).
The end of the divided anterior scalene muscle is elevated and its attachments to the underlying extrapleural fascia are sharply divided, avoiding electrocautery to prevent inadvertent nerve injury. Any muscle fibers extending from the posterior aspect of the muscle to the subclavian artery are divided to fully release the artery, and any scalene minimus muscle fibers (which pass between the roots of the brachial plexus) are divided. The anterior scalene muscle is then passed underneath and medial to the phrenic nerve, to better visualize and protect the upper brachial plexus nerve roots. The origin of the anterior scalene muscle on the C6 transverse process is palpated in the upper aspect of the operative field (the apex of the “scalene triangle”) and the muscle is divided with scissors under direct vision. The entire anterior scalene muscle is removed with a typical specimen weighing 5 to 10 g. Minor bleeding from the edge of the divided muscle origin should be controlled with a small polypropylene suture rather than electrocautery, given the proximity of the nerve roots (Fig. 10.5).
Middle Scalenectomy
The brachial plexus nerve roots are next approached at the edge of the middle scalene muscle. Using blunt fingertip dissection along the lateral aspect of the nerves, the exposure is extended deeper to the inner curve of the first rib and the extrapleural space. A small malleable retractor is placed between the brachial plexus nerves and the middle scalene muscle and with gentle medial retraction of the brachial plexus, each nerve root from C5 to T1 is sequentially identified (Fig. 10.6).
The transverse cervical artery and vein are usually identified where they pass through the brachial plexus and middle scalene muscle and should be ligated and divided to avoid bleeding.
The long thoracic nerve is gently retracted posteriorly, using a second malleable retractor placed lateral to the middle scalene muscle and the first rib. The attachment of the middle scalene muscle to the top of the first rib is then clearly exposed and carefully divided with the electrocautery. A periosteal elevator may be used as the dissection proceeds posteriorly, to a point parallel with the underlying T1 nerve root. The middle scalene muscle lying anterior to the long thoracic nerve is sharply excised, with a typical specimen weight of 3 to 8 g (Fig. 10.7). One to two figure-of-eight silk sutures are used along the edge of the middle scalene muscle to control minor bleeding, avoiding the electrocautery to avoid thermal injury to the C8 nerve root or long thoracic nerve.
Figure 10.5 The anterior scalene muscle (ASM) insertion is isolated by displacing the underlying subclavian artery (SCA) and brachial plexus (BP), using blunt fingertip dissection behind the muscle, and the subclavian vein (SCV) from in front of the muscle, and the muscle is sharply divided from the top of the first rib (ER) (A). The end of the divided ASM is lifted and sharply dissected free of structures lying behind the muscle, including the SCA (B). As it is mobilized, the ASM is passed underneath and to the medial side of the phrenic nerve (PhN) (C). The dissection is carried up to the level of the C6 transverse process, where the ASM can be safely divided from its origin and removed (D).
First Rib Resection
Maintaining the exposure used for middle scalenectomy, intercostal muscle attaching to the lateral edge of the first rib is separated from the bone with the electrocautery. The posterior first rib is fully exposed where the T1 nerve root emerges from underneath it, to join the C8 nerve root in forming the lower trunk of the brachial plexus. A right-angle clamp is passed underneath the posterior neck of the first rib and the instrument is gently spread to detach additional intercostal tissue, and a modified Giertz-Stille rib cutter is inserted around the neck of the first rib. After ensuring that the C8 and T1 nerve roots are well protected the bone is sharply divided, and a Kerrison bone rongeur is used to smooth the posterior end of the bone. The end of the bone is then sealed with bone wax (Fig. 10.7).
Figure 10.6 The brachial plexus is separated from the anteromedial border of the middle scalene muscle down to the level of the first rib and extrapleural fascia, and gently retracted medially to visualize all five nerve roots (C5 to T1).
Using blunt fingertip dissection, the remaining extrapleural fascia and intercostal muscle are separated from the undersurface of the rib, progressing anteriorly to the level of the scalene tubercle. It is not necessary to avoid opening the pleura during this portion of first rib resection, as any such opening will promote drainage of postoperative fluids away from the brachial plexus and thereby help to diminish perineural adhesions.
The subclavian vein and other soft tissues underneath the clavicle are elevated with a small Richardson retractor. Fingertip pressure is used to displace the posterior part of the first rib inferiorly, to open the anterior costoclavicular space. The subclavian artery and brachial plexus are then displaced laterally with a small malleable retractor, and the Giertz-Stille rib cutter is placed around the anterior first rib (Fig. 10.8). The first rib is then divided under direct vision immediately medial to the scalene tubercle, and the intact specimen is extracted from the operative field (Fig. 10.9). A Kerrison bone rongeur is used to remodel the remaining anterior edge of the first rib to a smooth surface, to a level well underneath the clavicle. Oxidized cellulose fabric (Surgicel, Ethicon, Inc.) is placed within the bed of the resected first rib as a topical hemostatic agent.
If a cervical rib is present, it is readily identified within the plane of the middle scalene muscle, posterior to the brachial plexus and subclavian artery, and anterior to the long thoracic nerve. An incomplete cervical rib will typically have a ligamentous extension to the first rib. Thus, the posterior cervical rib will be encountered during dissection of the middle scalene muscle and divided in the same manner as described for the posterior first rib. The anterior attachment of the cervical rib is subsequently divided and the bone removed prior to first rib resection. In contrast, a complete cervical rib will be attached to the lateral first rib in the form of a true joint. In this event, the anterior portion of the cervical rib is left attached while the first rib resection is completed, and the two are removed together as a single specimen (Fig. 10.9).
Figure 10.7 After detaching the middle scalene muscle (MSM) from the top of the posterolateral first rib using the electrocautery, the muscle tissue lying anterior to the long thoracic nerve (LTN) is excised (A). Typical operative specimens of the anterior and middle scalene muscles (B). The posterior first rib is exposed with visualization of the C8 and T1 nerve roots, and the rib is divided with a modified Giertz-Stille rib cutter (C). The posterior edge of the first rib is further remodeled with a Kerrison rongeur to obtain a smooth edge, immediately medial to the T1 nerve root (D).
Brachial Plexus Neurolysis
Supraclavicular decompression is completed by fully mobilizing the individual nerve roots contributing to the brachial plexus. Each nerve root from C5 to T1 is meticulously dissected free of any adherent perineural fibrous scar tissue (external neurolysis). In particular, there is often a small fibrofascial band overlying the most proximal aspect of the C8 and T1 nerve roots, which should be specifically sought out and resected (Fig. 10.10).
Figure 10.8 With the posterior end of the first rib pushed downward to open the anterior costoclavicular space, the anterior portion of the first rib is exposed underneath the clavicle and the subclavian vein (A). The subclavian artery (SCA) and brachial plexus (BP) are protected, and the anterior first rib is divided with a rib cutter immediately medial to the scalene tubercle (B).
Pectoralis Minor Tenotomy
Beginning at the level of the coracoid process, a short vertical incision is made in the deltopectoral groove. The deltoid and pectoralis major muscles are gently separated and the plane of dissection is carried deeper, medial to the cephalic vein. Using a small Deaver retractor, the lateral edge of the pectoralis major muscle is gently lifted. The tissue plane between the pectoralis major and minor muscles is separated by blunt fingertip dissection. The pectoralis minor muscle is palpated and the overlying fascia is exposed (Fig. 10.11).
The pectoralis minor muscle tendon is identified near its attachment to the coracoid process. The fascia along its medial and lateral borders is opened and the muscle is encircled using blunt fingertip dissection, taking care to avoid the short head of the biceps muscle, which also inserts on the coracoid process. With the underlying neurovascular bundle well protected, the pectoralis minor tendon is then elevated and its insertion on the coracoid process is divided with the electrocautery. After the lower edge of the divided pectoralis minor muscle has retracted inferiorly, releasing any compression of the neurovascular bundle, it is oversewn with a running silk suture to ensure hemostasis (Fig. 10.12).
Figure 10.9 Operative specimens following first rib resection (A) and following combined resection of a cervical rib and first rib (B).
Figure 10.10 Fibrous scar tissue is removed from each of the brachial plexus (BP) nerve roots by external neurolysis (A–C).
No further dissection of the brachial plexus nerves or axillary vessels is performed, but the remaining clavipectoral fascia is incised to the level of the clavicle, along with any other anomalous fascial bands that might be present over the brachial plexus. The wound is closed in layers without a drain after infiltrating the edge of the pectoralis major muscle with a long-acting local anesthetic.
Drain Placement and Closure
At the end of supraclavicular decompression, the pleural apex membrane is opened to promote postoperative drainage of fluid away from the brachial plexus into the chest cavity. A closed suction drain is placed into the operative field through a separate stab wound where it passes posterior to the brachial plexus with its tip extending into the posterior pleural space. Two multihole perfusion catheters are placed within the wound and connected to an osmotic pump for continuous postoperative infusion of local anesthetic (0.5% bupivacaine for 3 days). The brachial plexus nerves are wrapped with a bioresorbable polylactide film (SurgiWrap; Mast Biosurgery) to suppress postoperative perineural fibrosis. After restoring the scalene fat pad to its anatomic position overlying the brachial plexus, it is held in place with several silk sutures to the back of the sternocleidomastoid muscle and the periclavicular fascia. The platysma muscle layer is closed with interrupted sutures and the skin edges are reapproximated with an absorbable subcuticular stitch.
Figure 10.11 Pectoralis minor tenotomy is performed through a short vertical incision in the deltopectoral groove, just below the coracoid process (A). The plane of dissection is carried medial to the cephalic vein, and the pectoralis major muscle is lifted to expose the fascia over the pectoralis minor muscle (B).
Figure 10.12 The pectoralis minor muscle is encircled near its insertion on the coracoid process and then divided with the electrocautery (A). The retracted edge of the divided pectoralis minor muscle is oversewn with a continuous suture (B).
POSTOPERATIVE MANAGEMENT
An upright chest radiograph is performed in the recovery room. Any small air or pleural fluid collections are observed with the expectation of spontaneous resolution. Continuous-infusion perineural local anesthesia is used for pain control until postoperative day 3, along with patient-controlled intravenous opiates. The expected postoperative hospital stay is 3 to 4 days and at hospital discharge, an oral opioid, muscle relaxant, and nonsteroidal anti-inflammatory agent are routinely prescribed and continued for several weeks. The closed suction drain is typically removed in the outpatient office 5 to 7 days after surgery when its output is less than 50 mL per day.
The day after surgery, physical therapy is resumed to maintain range of motion and limit muscle spasm. No sling or other restraint is used on the upper extremity and the patient is allowed to use the extremity as tolerated. After hospital discharge, physical therapy is continued and the patient is advised to avoid excessive reaching overhead, heavy lifting with the affected upper extremity, and other activities that might result in muscle strain, spasm, and significant pain. Beginning 3 to 4 weeks after surgery, further rehabilitation is overseen by a physical therapist with expertise in the management of TOS in conjunction with a physical therapist located near the patient. A gradual, steady, return to normal use of the upper extremity is emphasized.
Most patients are permitted cautious light-duty work activity by 4 to 6 weeks after surgery, with progressively diminished restrictions on upper extremity activity. Recovery from surgery is typically considered to be complete between 6 and 12 weeks after operation. Follow-up visits are continued every 3 months in the first year to assess long-term results, and physical therapy and other aspects of care are continued as long as necessary to achieve an optimal level of function.
COMPLICATIONS
Persistent pain, numbness, and/or paresthesias.
Postoperative bleeding, localized hematoma, or hemothorax.
Wound infection (cellulitis or abscess).
Pleural effusion (serosanguinous).
Persistent lymph leak, chylothorax.
Brachial plexus nerve dysfunction (temporary or sustained).
Phrenic nerve dysfunction (temporary or sustained).
Long thoracic nerve dysfunction (temporary or sustained).
Recurrent NTOS.
RESULTS
Within several months of supraclavicular decompression for disabling NTOS, approximately 80% to 85% of patients can expect a substantial improvement in symptoms and increased functional use of the upper extremity compared to their condition prior to surgery. This rises to approximately 90% to 95% for patients who have had a positive anterior scalene/pectoralis minor muscle block prior to treatment.5 Other factors that are associated with less responsiveness to treatment include extremely debilitating and longstanding symptoms (often >5 years); pain syndromes with a widespread distribution; those who have had previous operations on the cervical spine, shoulder, or peripheral nerves for the same symptoms; age over 50 years; depression; and previous or ongoing use of opiate pain medications prior to surgery.
It is important to emphasize that patients with longstanding symptoms of NTOS may have some degree of residual symptoms despite appropriate thoracic outlet decompression, as surgical treatment cannot be assured to completely eliminate all symptoms. Such residual symptoms may still be quite tolerable compared to those present prior to surgery and most patients can expect to gradually improve further over time. The surgeon undertaking thoracic outlet decompression should recognize the need to provide continuing support and reassurance to the patient during the prolonged period of recovery and rehabilitation.
It has been shown that adolescent patients with NTOS have enhanced outcomes after surgical treatment compared to adults over 21 years of age, including assessment based on patient-reported survey instruments and use of opiate pain medications. Recent reports also indicate that the early outcomes for surgery in patients selected for isolated pectoralis minor tenotomy are similar to patients who have undergone combined supraclavicular decompression and pectoralis minor tenotomy, but these patients should be closely followed for development of recurrent symptoms, which may warrant subsequent supraclavicular decompression.
Recurrent NTOS occurs in approximately 2% to 5% of patients undergoing surgical treatment, usually within the first 2 years after operation. Development of recurrence in a patient who has previously had good results after surgery is often associated with a secondary injury, likely as the result of perineural inflammation and accelerated fibrosis. The supraclavicular approach is optimal for reoperations for NTOS, providing the most complete exposure of the relevant anatomy with the greatest degree of safety.1 In these procedures, the scalene fat pad is reflected in the same manner as in a primary operation and the brachial plexus nerve roots are carefully exposed and mobilized. Given the dense fibrous scar tissue that is usually present within the operative field, it is especially important to avoid nerve and blood vessel injury during this dissection. If any of the pertinent anatomic structures were retained at the initial operation, such as the anterior and middle scalene muscles, anomalous fibrofascial bands, and/or the first rib, these are removed. An extended and complete brachial plexus neurolysis is then performed. Prior to closure, the brachial plexus is encircled with a bioabsorbable film and covered by reapproximating the scalene fat pad.
CONCLUSIONS
The surgical treatment of NTOS is founded on a sound clinical diagnosis, the presence of disabling symptoms, and failure of these symptoms to improve with a suitable trial of physical therapy management. Imaging studies, electrophysiologic tests, and vascular laboratory examinations may be useful in the exclusion of other conditions, but they add little in the specific diagnosis of NTOS. Clinical findings leading to a diagnosis of NTOS may be strongly supported by a positive anterior scalene/pectoralis minor muscle block, which also demonstrates the likelihood of a favorable response to surgical treatment. In addition to findings referable to the scalene triangle, the potential contribution of brachial plexus compression at the level of the subcoracoid (pectoralis minor) space should always be assessed and included in surgical treatment if present.
Proper mobilization and lateral reflection of the scalene fat pad is a key step in simplifying supraclavicular exposure for thoracic outlet decompression. This permits the critical view to be obtained in which all of the relevant structures can be visualized in the same operative field: The internal jugular vein, phrenic nerve, anterior scalene muscle, brachial plexus, middle scalene muscle, first rib, and long thoracic nerve. The thoracic duct should be ligated and divided, if necessary, to prevent postoperative lymph leak.
During anterior scalenectomy, all fibers passing from the posterior aspect of the anterior scalene muscle to the subclavian artery and the extrapleural fascia should be divided, along with any scalene minimus muscle encountered. Once divided from the first rib and elevated, the anterior scalene muscle should be passed underneath and medial to the phrenic nerve, to facilitate dissection of the muscle to its origin on the C6 transverse process.
During mobilization of the brachial plexus, all five nerve roots should be well visualized and only gently retracted. The transverse cervical vessels should be ligated and divided where they pass through the brachial plexus and middle scalene muscle. During division of the middle scalene muscle from the top of the first rib, the long thoracic nerve should be visualized and protected. Any cervical rib present should be resected before resection of the first rib. Prior to division of the posterior first rib, the T1 and C8 nerve roots should be well visualized and protected from injury, and any small fibrofascial bands present over the proximal aspect of the C8 and T1 nerve roots should be resected. A small segment of the divided posterior first rib should be removed to facilitate fingertip dissection underneath the remaining lateral and anterior portions of the bone. It is not necessary to avoid opening the pleura during dissection of the first rib. The anterior first rib is divided underneath the clavicle and subclavian vein, at a level medial to the scalene tubercle, while protecting the subclavian artery and brachial plexus. Any fibrous scar tissue should be thoroughly removed from around each nerve root of the brachial plexus (C5 to T1), to maximize nerve mobility and to avoid one of the principal causes of persistent symptoms. The brachial plexus is subsequently wrapped with a bioresorbable film to minimize perineural fibrosis. Pectoralis minor tenotomy is included with supraclavicular decompression if there are concomitant symptoms of NTOS referable to the subcoracoid space.
A closed suction drain is placed into the supraclavicular space behind the brachial plexus, with its tip extending into the pleural space, to be removed approximately 6 to 7 days after operation. Continuous postoperative infusion of a local anesthetic into the operative field can help diminish the need for opiate pain medications.
The large majority of patients (85% to 90%) with disabling NTOS can expect a substantial improvement in symptoms and upper extremity function within several months of supraclavicular decompression. Diminished responsiveness to treatment tends to be associated with extremely longstanding (>5 years) and debilitating symptoms, widespread pain syndromes, multiple previous operations (cervical spine, shoulder, or peripheral nerves), depression, older age (>50 years), and pre-existing use of opiate pain medications.
Recommended References and Readings
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