Clinical research
Surgical treatment of thoracic outlet syndrome: immediate and mid-term results

Introduction
Subclavian artery or vein occlusion is an uncommon but potentially disabling condition that affects relatively young people. Thoracic outlet syndrome (TOS) can occur with symptoms of nerve or vessel compression as they pass through the thoracic outlet. The majority of symptoms associated with TOS are neurogenic, accounting for more than 95% of initial symptoms, with venous or arterial compression symptoms accounting for 2 and 1% respectively according to the literature [1-3]. Cervical rib or first rib anomalies can be detected in 8.5% of symptomatic TOS in major series; an anomaly of the scalene muscles appear to be responsible for TOS in 43% of cases [4]. Some studies have underlined the importance of predisposing morphological variations, structural modifications conditioned by functional requirements and changes in fibre type or myosin isoform consequent to trauma in development of TOS [5, 6]. In patients with symptoms of nerve or vascular compression surgical decompression at the thoracic outlet is mandatory. It can be achieved by cervical or first rib resection, scalenectomy and vascular reconstruction if necessary. Surgical treatment of TOS began in 1861 with the first cervical rib excision performed by Coote [7]. Currently the two techniques that predominate are the transaxillary approach for resection of the first rib as introduced in 1966 by Roos and Owens [8], and scalenectomy, which was described in 1927 by Adson and Coffey [9]. In 1979 Sanders et al. [10] reported the first successful series of scalenectomies. Although the majority of patients appear to benefit from surgery when appropriately performed, conservative management, particularly physiotherapy, seems to relieve symptoms completely in a significant proportion of patients. Moreover, because of the high recurrence of symptoms in surgically treated paucisymptomatic patients (15-20%) [11, 12] the type and role of surgery in this syndrome are controversial. We report the results in a consecutive series of patients treated by scalenectomy or cervical/first rib resection for clearly symptomatic or paucisymptomatic thoracic outlet syndrome over a 6-year period.
Material and methods
From September 1999 to August 2005 at our institution, 14 surgical decompressions were performed in 12 patients with unremitting signs and symptoms of nerve or vascular compression at the thoracic outlet. In 8 cases surgery was performed after failure of a 6-month period of physical therapy [13], 2 underwent emergency surgery, and 4 were previously treated for deep vein thrombosis and then were submitted to operation. Median age was 31.4 years, with a range of 20 to 40 years, and the majority of patients were female (83%). No history of trauma was reported. Duration of symptoms related to thoracic outlet was 0 to 24 months. The side affected was right in 4 cases (33.3%) and left in 6 cases (50%). In two cases the syndrome was bilateral (Table I). Initial symptoms and signs are listed in Table II. As in most series neurogenic symptoms and shoulder or arm pain were reported by the majority of cases (13, 92.8%). The symptoms of TOS were due to involvement of the brachial plexus in 8 cases (57.1%). A sign of vascular obstruction could be detected in 10 cases (71.4%): in 6 cases (42.8%) the presentation was predominantly arterial (arm claudication, coldness, Raynaud’s phenomenon and distal embolisation) and in 4 cases (28.5%) was related to vein compression with congestion and swelling of the affected arm or vein thrombosis. Two patients presented as emergencies with critical upper limb ischaemia or distal vessel embolisation. Diagnosis was achieved by clinical examination with provocative tests, chest X-rays for cervical or first rib anomalies detection, Duplex Doppler with provocative tests, electromyography, CT scans or MR examination for fibrous band or scalene muscle anomaly detection. Arteriography and venography were performed with the arm in adduction and abduction in 9 patients presenting with predominantly arterial or venous symptoms (Figure 1). In 3 cases the vasculopathy was caused by a supernumerary cervical rib that was in an intermediate stage of development with a fibrous band attaching it to the first rib. Hypertrophic anterior scalene muscle was found in all cases. The median follow-up period was 28.2 months (range 8-78 months).
Results
Results were evaluated in terms of technical success, lack of complications (temporary or permanent plexus injury, temporary or permanent phrenic palsy), and relief of symptoms. Outcome data were divided into immediate/perioperative and mid-term results. All patients had an anterior scalenotomy through a standard supraclavicular approach (Table III). First transaxillary approach was not used in this series. In 3 patients we performed a cervical rib excision with an extended surgical approach: all of them presented an incomplete cervical rib with a fibrous band connecting it to an identifiable promontory on the first thoracic rib. No patients needed first rib resection or arterial or vein reconstruction (Table III). A 23-years-old female presented with acute left upper limb ischaemia (Figure 2); we performed at first locoregional fibrinolysis with urokinase (initial bolus of 300,000 UI followed by 50000 UI/h) for 24 hours and then we treated the subclavian artery lesion with PTA and stenting (Easy Wallstent, Boston Scientific; Figure 3); during endovascular treatment digital subtraction angiography demonstrated compression of the subclavian artery by an incomplete cervical rib so we finally performed cervical rib excision and scalenotomy. At present she is asymptomatic and the arm is well perfused with symmetrical brachial occlusion pressures.
Perioperative results
There was no operative mortality. Two patients (14%) developed a temporary phrenic palsy that made complete recovery within seven days. Technical success rate was achieved in all patients in excision of fibrous band with scalenectomy and in cervical rib excision. Moreover we registered no postoperative bleeding or wound infection/dehiscence. Median postoperative in-hospital stay was 2.7 days (range 2-8 days).
Mid-term results
The median follow-up period was 28.2 months. Follow-up clinical examination was divided in terms of their neurological, arterial or venous presentation; relief of symptoms was evaluated as complete, partial, none or as worsening of them. There was no procedure-related deaths. In 4 patients with venous symptoms complete relief was achieved in 75%. In all patients that experienced arterial complications we registered complete relief. In patients with neurological presentations we detected complete relief in 5 (62.5%), relief of some symptoms in 2 (25%) and no improvement in 1 (12.5%).
Discussion
In our series 42.8% of the cases presented with arterial symptoms. This can partially be explained by the small sample size of our series and the lack of a designated vascular unit in a 100 km² area. Moreover, it underlines the importance of angiography in the detection and diagnosis of TOS. In one case presenting with critical upper limb ischaemia digital subtraction angiography was performed with diagnostic and therapeutic purposes. Fibrinolysis and stenting of the subclavian artery allowed us to readily save the affected arm. Nevertheless the manifestation of a new acute ischaemia after one day led us to choose a surgical treatment. Technical success was achieved in all patients by a supraclavicular approach with scalenectomy performed in every patient and additional cervical rib excision wherever detected. We needed no transaxillary surgical approaches because no first rib compression of the nerve or vessels crossing the thoracic outlet was detected on provocative tests and imaging. Supraclavicular incision with extended edges provided good exposure of the cervical rib and anterior scalene muscle for excision and good exposure of vessels for eventual reconstruction or vascular complication requiring direct intervention [4]. In most of the series detection of an obvious anatomical anomaly led to better results. Makhoul et al. [4] reviewed the anatomical anomalies encountered in their extensive experience of 200 patients submitted to surgery for symptoms of thoracic outlet compression: it is of interest to note that only 8.5% of their patients had a cervical rib or an anomaly of the first rib, while an anomaly of the scalene muscle was identified in 43% of patients, with 22.5% of patients having more than one anomaly. Desai and Robbs [14] reported a complete cervical rib in 60% of their patients surgically treated for TOS. In Lindgren et al. [15] the result of surgery was considered successful in 59% at a two-year follow-up; patients with a favourable outcome of surgery had a significantly higher incidence of an anomaly when compared to patients with poor results after surgery. In our series cervical rib accounted for just 21.4% of symptoms of TOS; our experience underlines the importance of the role of scalene muscle and its development in response to growth or functional hypertrophy in occurrence of symptoms of TOS. Numerous surgical case series have been reported that have claimed good to excellent results in 50 to 90% of patients undergoing thoracic outlet decompression [3, 10, 15-22]. Narakas et al. [23] reported satisfactory results in 65% of patients. Nevertheless, in all series reported no objective evaluation method is described; the results are reported by the operating surgeon and this can introduce bias because function results can only be reported in subjective terms. Furthermore the length of follow-up in these studies is variable: at prolonged follow-up data seem to indicate a worsening of results. Lepäntalo et al. [24] reported the follow-up of 75 patients undergoing first rib resection for TOS. One month after surgery 52% of limbs were asymptomatic and 77% were improved. At a mean follow-up of 6 years, patients were re-evaluated by independent examiners: a permanent success rate of the operation of only 37% was reported. Sanders in 1996 [25] reported a complete resolution of symptoms in just 43% at an eight-year follow-up. In a recent report by Urschel and Kourlis [26] on their fifty-year experience at Baylor University Medical Center in 5102 patients treated for TOS, the first-operation results were good in 85%, fair in 12% and poor in 3%; in patients with classic TOS 95% reported improvement shortly after surgery, while 90% reported improvement at 5-year follow-up; in those with cervical spine involvement 75% reported early improvement and 50% late improvement; finally in patients undergoing a therapeutic trial early and late improvement were reported respectively in 70 and 50%. In conclusions we emphasize the importance of an objective method of evaluation and the necessity of a prolonged follow-up [27]. In our experience patients treated at first with physical therapy were subsequently submitted to surgical decompression, in most of the cases gained with anterior scalene muscle resection. These data cause a lack of “control cases” in our series to compare surgery versus physiotherapy but seem to indicate better results in terms of relief of symptoms and return to work after surgery.
References
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