Supraclavicular approach for outlet decompression. thoracic. Linda M. Reilly, MD, and Ronald J. Stoney, MD, San Francisco, Calif.

Transcription

1 Supraclavicular approach for outlet decompression thoracic Linda M. Reilly, MD, and Ronald J. Stoney, MD, San Francisco, Calif. Supraclavicular decompression of the thoracic outlet was performed in 40 patients with symptoms arising from brachial plexus compression and irritation. Both osseous and soft tissue structures responsible for this nerve compression were identified and removed without significant neurologic morbidity despite a 25% incidence of secondary operative procedures in this series. The cure or improvement rate matched what we previously reported for combined transaxillary and supraclavicular approach. Further follow-up will auow a determination of the durability of this technique, which, ff acceptable, will justify a confident recommendation for its adoption in patients having thoracic outlet decompression. (J VASC SURG 1988;8: ) Mechanical compression of the brachial plexus within the thoracic outlet is considered the principal cause of neurologic complaints in symptomatic patents. Although there is no consensus regarding a treatment plan, conservative measures are usually initiated, reserving surgical decompression for patients whose treatment fails or whose conditions worsen. Among the varied operative approaches and techniques advocated, _transaxillary resection of the first rib is the most popular. 1 Symptomatic recurrence caused by fibrotic encasement of the plexus trunks and reattachment of the scalene muscle to the first rib bed prompted our use of a combined transaxillary rib resection and supraclavicular radical scalenectomy with improved results? Continued experience has convinced us that the safe exposure of the first rib can be regularly achieved by means of the supraclavicular approach alone. In addition to resection of the first rib, scalenectomy and precise identification and removal of osseous and myofascial abnormalities are simplified with this approach. This article describes our technique and the results achieved in 41 supraclavicular thoracic outlet decompressions in 40 consecutive patients treated at the University of California Medical Center, San Francisco. From the Department of Surgery, University of California, San Francisco. Supported in part by the Pacific Vascular Research Foundation, San Francisco, Calif. Presented at the Second Annual Meeting of the Western Vascular Society, Tucson, Ariz., Jan , Reprint requests: Ronald J. Stoney, MD, Dept. of Surgery, Vascular Surgery, M-488, University of California, San Francisco, 505 Parnassus Ave., San Francisco, CA PATIENTS AND METHODS During the past three years 36 women and four men ranging in age from 18 to 66 years (mean 37 years) had 41 supraclavicular thoracic outlet decompressions to relieve pain and paresthesia mediated through the roots of the brachial plexus. Five additional patients with symptoms arising from compression of the subclavian artery (four patients) or subclavian vein (one patient) also had surgery with an identical supraclavicular approach. However, these patients required either arterial repair or venous decompression and will not be considered in this article. The left upper extremity was the site of neurologic complaint in 22 patients, slightly more than half of the group. In 10 instances, 25%, the procedure was a second operation. The original thoracic outlet decompression that failed was a transaxillary first rib resection in nine patients and a supraclavicular scalenectomy in one patient. A history of cervicothoracic trauma, usually involving a hyperextension force, preceded the onset of symptoms in half of our patients (n = 20). The duration of symptoms ranged from 5 months to 13 years (mean 3 years) before operation. In 30 patients, a supervised conservative treatment program involving analgesics, muscle relaxants, physical therapy, exercise, and occasionally chiropractic, acupuncture, or biofeedback adjuncts had failed to produce sustained improvement. Five patients had no conservative treatment whereas in six others sporadic attempts or undefined nonoperative treatment were noted. Although the pattern of symptoms varied, several consistent features were (1) pain involving the lateral 329

2 330 Reilly and Stoney Journal of VASCULAR SURGERY fa Middle Scaler Nuacle Co~ThoTacic N~Yv~ Fig. 1. Artist's illustration of early stage of right thoracic outlel: decompression. Note the self-retaining retractor. Fat pad is retracted to expose brachial plexus. A~teyior 9calene (cut) ~U l Fig. 3. Illustrated detail of sagittal saw division of neck of first rib. Dong thoracic nerve course parallel and caudad to transected middle scalene is seen. #ll& L 0 ~ ~ I N~.Yv~ t~racl~ Plexu Clgvic: 5uloclav: Arte~'y j~iddl~ Mctscl~ Lo~ T~ NcYv Brachial Clav}cl.C. Fig. 2. Artist's illustration of decompression landmarks, site of retraction of anterior scalene, partial resection of middle scalene muscle and first rib. Transection site (dotted line). Brachial plexus and artery are seen. Medial clavicle and part of subclavian vein are removed for illustrative purposes. R.C.C., Right common carotid artery. neck, shoulder, parascapular region, and upper extrernil~, and (2) paresthesia principally affecting the arm, hand, and fingers. These two principal complaints were brought on or intensified by the use of the ipsilateral arm in extended, elevated, or overhead positions. Ipsilateral headache, facial pain, or both were present in 17 patients (42.5%). Pertinent physical findings were 5ubc]a\ Artery ~b Z ~ Fig. 4. Thoracic outlet decompression shows the relaxed, nonstretched portion of the third division of the brachial plexus nearly contacting the second thoracic rib. Medial clavicle is removed for illustrative purposes. direct tenderness over the brachial plexus, trapezius muscle spasm, and the reproduction or intensification of neurologic symptoms by hyperabduction maneuvers or the elevated arm stress test (EAST). Preoperative evaluation usually included orthopedic and neurologic consultation as well as roent-

3 Volume 8 Number 3 September 1988 Supradavicular decompression of the thoracic outlet 331 genograms of the chest and cervical spine, Nerve conduction studies were used specifically when nerve entrapment at the wrist or elbow was suspected. Myelography, computed tomography, and more recently magnetic resonance imaging have been used to evaluate suspected cervical disk disease. OPERATIVE TECHNIQUE The patient is placed in a semi-fowler position with the head rotated away from the operative side. An incision is made two finger breadths above the davicle, beginning over the clavicular head of the sternocleidomastoid muscle. The incision is carried laterally and posteriorly in a gentle curve for a distance of approximately 10 cm. The platysma is incised and flaps are developed superiorly, to the level of the cricoid cartilage and inferiorly, to the clavicle. The scalene fat pad is mobilized inferiorly, medially, and superiorly and then reflected on a laterally based pedicle (Fig. 1). The clavicular head of the sternocleidomastoid muscle is divided when necessary to gain medial exposure to the lateral edge of the internal jugular vein. The phrenic nerve is mobilized from the adjacent fascia of the anterior scalene muscle and retracted medially. The insertion of the muscle is detached from its tubercle on the first rib. The muscle is elevated to visualize the subclavian artery and the trunks of the brachial plexus. The origins of the anterior scalene muscle are divided from the transverse processes of the upper cervical vertebrae. Any muscle fibers that interdigitate with the middle scalene muscle between the roots of the brachial plexus are now divided and the anterior scalene muscle is then removed. Gentle anterior displacement of the brachial plexus trunks allows their separation from the anterior surface of the middle scalene muscle. The lateral border of the middle scalene muscle is freed and the point of emergence of the long thoracic nerve is identiffed. This point serves to identify the level for middie scalene muscle transection to expose the neck of the first rib (Fig. 2). A sagittal air-drive saw is used to divide the rib posteriorly, while the lower trunk of the plexus is gently displaced anteromedially (Fig. 3). The lateral border of the middle scalene muscle and the first rib are mobilized and the intercostal muscle between the first and second rib as well as the posterior scalene muscle are now divided. Next the trtmks of the plexus are elevated and the medial border of the first rib is freed. The subclavian artery is displaced caudally, which further exposes the course of the first rib. Anomalous myofascial bands Table I. Abnormalities and anomalies No. Scar 13 Osseous anomalies 22 First rib 8 Cervical rib 10 C-7 transverse process 3 Pseudarthrosis 1 Myofascial abnormalities 66 Muscle 44 Fibrous bands 22 that insert on the rib are now identified and resected. Blunt finger dissection inferior to the first rib separates it from the subjacent pleura, which can then be displaced inferiorly. The final dissection of the anterior first rib requires elevation and retraction of the clavicle and the lateral displacement of the trunks of the brachial plexus and subclavian artery. The rib is then divided with a sagittal saw beyond the anterior scalene tubercle (Fig. 3). It is now gently freed of any other attachments and removed from beneath the neurovascular structures. The course of the five roots of the plexus and their fusion into three cords is inspected and any scar tissue or residual muscle fibers are removed by thorough neurolysis. The neurovascular structures lay loosely in the enlarged thoracic outlet (Fig. 4). Should the proximal rib stump impinge on ~the upward course of the first thoracic nerve root, a rongeur is used to resect additional bone from the medial corner of the remnant rib. The mobilized prescalene fat pad is now split into two leaves, which are positioned loosely to surround the trunks of the brachial plexus. This provides a soft fibrous fatty insulating collar to protect the delicate nerve roots. The clavicular head of the sternocleidomastoid muscle and platysma are reapproximated and the skin is closed with a subcuticular suture. If lung inflation shows a plcural defect, a soft catheter is placed through the wound into the pleural cavity before closure. The chest is evacuated by aspiration and the catheter is withdrawn from the closed wound before the bandage is affixed. A portable chest roentgcnograrn in the recovery room will usually show a reexpanded lung or very small apical density or pneumothorax. Any pneumothorax greater than 20% can be evacuated easily with a plastic catheter inserted anteriorly through the third intercostal space. After recovery from anesthesia the patient is allowed unrestricted activity with full range of motion of the major joints of the affected extremity. The patient is usually discharged by the third postoperative day.

4 332 Reilly and Stoney Journal of VASCULAR SURGERY Table II. Thoracic outlet decompressive procedures Scalenectomy Rib resection Neurolysis No. Anterior and middle First rib Brachial plexus 31 ~ Anterior and middle Cervical rib Brachial plexus 6 Anterior and middle First and cervical rib Brachial plexus 2 Anterior Cervical rib Brachial plexus 2 Cervical sympathectomy (one patient). Table III. Follow-up intervals with mtmber of patients at each interval Interval (too) No. < >24 4 OPERATIVE FINDINGS The supraclavicular approach provides unrestricted exposure to the course of the first thoracic rib, the interscalene triangle, and the osseous and musculofascial abnormalities found in this region. Many patients had more than one abnormality noted. The scalene minimus, considered by some authors to be a normal anatomic variant, was noted in 17 patients (42%). Excluding this finding, the mean number of anomalies was 2.5 for the entire group (Table I). These included fibrosis or scarring along the posterior border of the anterior scalene muscle, the anomalous bands overlying the lower roots of the plexus, or a reattachment of the previously divided anterior scalene tendon to the first rib bed after a prior transaxillary rib resection. Osseous abnormalities included a cervical rib in 10 patients, a broad first thoracic rib in eight patients, and an elongated transw:rse process of the seventh cervical vertebra in three patients. Myofascial abnormalities were frequent. Hypertrophy of the anterior scalene muscle (nine patients) was observed in overdeveloped persons who had usually pursued a vigorous muscular development (power-lifting) program. The resected first rib with intact middle scalene muscle insertion provided a specimen to assess the pattern of muscular insertion. A frequent finding was a broad, anteriorly displaced insertion of this muscle that abutted the posterior aspect of the anterior scalene tubercle. The operative procedures required to decompress the thoracic outlet are listed in Table II. As can be seen, the most common procedure used was anterior and subtotal middle scalenectomy and first thoracic rib resection with brachial plexus neurolysis (31 procedures). In 10 procedures, a cervical rib was encountered and resected either alone (eight procedures) or in conjunction with the first thoracic rib (two patients). RESULTS This group of patients were all operated on within the past 30 months. Thirty-eight patients have been personally examined between 1 and 30 months postoperatively (mean 10 months) (Table III). Symptoms were assessed with a scoring system to attempt to objectify the results. The scoring system form is described in Table IV. If all of the preoperative symptoms were consistently relieved, the patients were cured. If greater than 75% of the preoperative symptoms were consistently relieved on follow-up, the patients were classified as markedly improved. Fifty to seventy-five percent preoperative symptomatic relief was considered improved and anything less than that was considered unchanged. Only three patients were believed to be unchanged after operation (8%), 13 patients were cured, 10 patients were markedly improved, and 13 were improved. No patient was worse after this operative approach. Complications. Many patients had some complications of their supraclavicular decompression procedure. Most were minor, involved the wound, and nearly all resolved before hospital discharge. A pneumothorax occurred during 33 of 41 procedures; however, in only half was a chest tube temporarily required as the remainder were evacuated in the operating room. Mild brachial plexus traction palsy was noted in five patients postoperatively. This was transient in all, was substantially improved by discharge, and was completely resolved within 3 months after operation. One patient had a subclavian venous injury repaired and another had a self-limited chylothorax. These patients both had a prior thoracic outlet decompression. One patient had a winged scapula

5 Volume 8 Number 3 September 1988 SupracIavicular decompression of the thoracic outlet 333 Table IV. The supraclavicular thoracic outlet syndrome decompression quantitative symptom assessment form Pain Rest Motion Paresthesia Rest Motion Weakness Reduced motion Headache Neck Shoulder Scapula Thorax Arm Hand Yes No NOTE: One was completed for each patient before operation and at each assessment interval after operation. resulting from a long thoracic nerve injury. Phrenic nerve dysfunction was not specifically evaluated, but in 10% of patients, an elevated ipsilateral hemidiaphragm was noted on postoperative chest x-ray films. Only one patient had persistent mild elevation of the left hemidiaphragm with atypical chest pain and shortness of breath. One patient had minimal ptosis and miosis without the other components of Horner's syndrome. DISCUSSION The factors responsible for brachial plexus compression within the thoracic outlet are multiple. Furthermore, no symptom pattern, physical findings, or electrodiagnostic test can reliably predict the anatomic findings in any individual case. It is obvious from this patient group, that congenital myofibrous and osseous anomalies are frequent and, when combined with acquired structural changes, averaged 2.5 findings per operated patient. Most osseous abnormalities are in the neck itself whereas the muscular anomalies and acquired structural changes are superior to the first rib, involving the scalene triangle and the interroot spaces themselves. None is easily visualized without a thorough anterior scalenectomy 3 and gentle exposure of the roots and trunks of the brachial plexus itself. The transaxillary approach involves a deep narrow exposure and limited visualization of structures cephalad to the superior aspect of the first rib. It cannot reliably and safely permit the precise identification, let alone the resection of, complex anomalies in juxtaposition to the course of the delicate nerve structures themselves. The importance of abnormal and structurally normal-appearing scalene muscle in neurogenic thoracic outlet syndromes has been recognized for half a century. 4's Naffziger and Grant 6 described the scalene anticus syndrome. It was postulated that a chronically contracting, taut anterior scalene muscle elevated the first rib compressing the plexus against the underside of the clavicle. 7 No histopathologic analysis of the anterior scalene muscle in symptomatic patients was obtainable until recently. Machleder et al.s used histochemical studies for fiber typing and quantified hypertrophy and atrophy factors in patients with thoracic outlet neurogenic syndromes and normal patients. They observed scalene hypertrophy of the type 1 fiber system in symptomatic patients with intact anterior scalene muscles. After anterior scalene tenotomy this fiber type atrophied. They con: eluded that these changes substantiated that longterm increased tone in the anterior scalene muscle may explain symptoms in patients without other obvious structural anomalies and symptoms in patients who had stretch injury to the musculature in this region. These observations may further support our view that adequate decompression of the thoracic outlet includes scalene muscle resection. Certainly, the supraclavicular approach 9 affords ideal exposure for this maneuver. Subtotal resection of the middle scalene with the attached first rib is readily accomplished with no significant morbidity. Removal of osseous anomalies when encountered can easily be justified because they are usually precipitating factors for all forms of neurovascular compression in the thoracic outlet. When the varied underlying factors responsible for neurogenic symptoms are considered, any surgical procedure in this region should include a thorough decompression of the plexus. A complete excision of the anterior scalene muscle ensures it will not reattach to the first rib bed with recurrent symptoms. Furthermore, removal of this muscle affords complete exposure of the proximal brachial plexus anteriorly and other soft tissue anomalies. Transection of the middle scalene muscle facilitates exposure of neck of the first rib for precise division and subsequent removal. This results in an

6 334 Reilly and Stoney Journal of VASCULAR SURGERY enlarged space posterior to the brachial plexus and first rib bed. In previous reports, authors usually emphasized the importance of either osseous or soft tissue structures but rarely both. Roos 3 used a combined approach for second operations and in selected patients with middle and upper plexus involvement. Our ]previous report recommended the combined remowd of osseous and soft tissue abnormalities with a combined operative approach? Sanders and Rayner, 9 in describing their supraclavicular approach to scalenectomy and first rib resection reported that in occasional patients, difficult or impossible exposure of the neck of the first rib justified limitation of the operation to scalenectomy alone. If significant symptoms persisted, they proposed later transaxillary resection of the first rib. In our experience, total thoracic outlet decompression including first rib resection by the supraclavicular approach can reliably be achieved. In the eight patients in this study in whom the first rib was not removed, a large cervical rib simulating the course of the first rib was interpreted as the', cause of nerve compression. In such instances, additional removal of the first thoracic rib did not appear justified, but it was technically feasible. Complications in this series are numerous but trivial Pneumothorax is not unexpected after this operation and is easy to treat. The potential for nerve injtu3/in this region is a major risk to a patient having thoracic outlet decompression. Wide exposure, selfretaining retraction, and fiber-optic illumination facilitave the meticulous dissection required. Traction paresis is the cause of most nerve palsies that occur after operations in this region but they resolve quickjty. After resection of the anterior scalene muscle and any osseous or fibrous anomalies, first rib removal without undue traction on the plexus is accompfished because the enlarged area and relaxed strucvares accommodate moderate displacement. The course of the phrenic and long thoracic nerves are reliably constant and can be visualized and retracted to avoid injury. In second operations, the precise identification of delicate nerve trunks and the lymphatic and chylous ducts is difficult when they are enveloped by scar tissue. Nonetheless, these repeat operations can be achieved with only a slightly higher risk of complications. Most are done after failure of transaxillary procedures and the exposure cephalad to the first rib bed is rarely obscured by scar tissue. We deliberately expose and mobilize the roots and trunks of the plexus to conduct a thorough neurolysis in second operations. This assures us that these structures can be protected during the removal of scar tissue and anomalous structures in this vicinity. We have not observed any unusual morbidity associated with careful plexus mobilization and gentle retraction and believe it is safer than the avoidance of the plexus. When adjacent fibrous tissue or soft tissue anomalies are overlooked that are responsible for recurrent or persistent neurogenic symptoms after a prior operation, the interest of the patient is not well served. Furthermore, a substantial scar tissue barrier to brachial plexus decompression awaits the surgeon who may unfortunately be required to perform a later third operation. REFERENCES 1. Roos DB. Experience with first rib resection for thoracic outlet syndrome. Ann Surg 1971;173: Qvaffordt PG, Ehrenfcld WK, Stoney RJ. Supraclavicular radical scalenectomy and transaxillary first rib resection for the thoracic outlet syndrome. Am J Surg 1984;148: Roos DB. The place for scalenectomy and first rib resection in thoracic outlet syndrome. Surgery 1982;92: Adson AW. Surgical treatment for symptoms produced by cervical ribs and the scalenus anticus muscle. Surg Gynccol Obstet 1947;85: Roos DB. Congenital anomalies associated with thoracic outlet syndrome-anatomy, symptoms, diagnosis and treatment. Am Surg 1976;132: Ochsner A, Gage M, DeBakey M. Scalenus anticus (Naffziger) syndrome. Am J Surg 1935;28:669-93, 7. Naffziger HC, Grant WT. Neuritis of the brachial plexus, mechanical in origin: the scalene anticus syndrome. Surg Gynecol Obstet 1938;67: Machleder HI, Moll F, Verity AM. The anterior scalene muscle in thoracic outlet compression syndrome. Arch Surg 1986; I21: Sanders RJ, Kayner S. The supraclavicular approach to scalenectomy and first rib resection: description of techwique. J VASC SURG 1985;2:751-6.