Diagnosis, treatment, and complications of thoracic outlet syndrome

BACKGROUND AND PURPOSE: The present study investigated the influence of the antiplatelet agent acetylsalicylic acid (ASA) on cerebral microembolism as detected by transcranial Doppler sonography (TCD). METHODS: Nine patients with recent transient ischemic attack or minor stroke of arterial origin were investigated. Eight had not received an antiplatelet or anticoagulant medication before TCD, and in 1 patient a preexisting ASA medication (100 mg/d) had not been changed since the onset of stroke symptoms. An initial 1-hour TCD monitoring was extended for an additional 2.5 hours after an intravenous bolus injection of 500 mg ASA and was repeated for 1 hour on the following day. RESULTS: Microembolic signals (MES) were detected in all patients only on the symptomatic side. After the ASA bolus injection, a significant drop of the MES rate was found in 7 patients, all without previous medication, starting 30 minutes after the application (mean per hour=25.1 [range, 6 to 66] versus mean per hour=6.4 [range, 0 to 14]). In 3 of these patients, platelet aggregation tests were performed that demonstrated normal aggregation before bolus injection and inhibited aggregability as early as 30 minutes after bolus injection. The rate of MES remained unchanged in 1 patient without antiplatelet medication. The ninth patient, who had suffered an ischemic event on ASA, showed only a transient decrease of MES frequency. CONCLUSIONS: In patients with recent stroke of arterial origin, intravenous ASA can rapidly reduce cerebral microemboli as detected by TCD. Microemboli might be a useful parameter to monitor early effects of antiplatelet therapy.     

Desmoid tumour of the thoracic outlet: an unusual cause of thoracic outlet syndrome

Several electrocardiographic anomalies have been described in association with hypoglycaemia. We report the case of a 70-year-old woman with hypoglycaemic coma whose electrocardiogram showed significant conduction anomalies, including atrioventricular block and intraventricular conduction disturbances, and repolarization abnormalities. These electrocardiographic changes disappeared after intravenous glucose administration.     

Aneurysms of the subclavian artery in thoracic outlet syndrome

The true subclavian artery aneurysm is a rare but dangerous complication of TOS. During a 20 years time period we observed 18 patients with subclavian artery aneurysms. 12 of these patients showed cervical ribs. Half of the patients (n = 9) presented with a critical ischemia of an upper extremity, nine patients were operated on electively. The acute ischemia makes the desobliteration of the outflow tract necessary first. The next step ist the transaxillary exarticulation of the first rib and the resection of the aneurysm. The reconstruction of the subclavian artery is performed by using autologous vein material or PTFE prostheses. In two cases both with an acute embolic critical ischemia major amputations were unavoidable. 13 patients could be reexamined in 1996: 11 bypasses proved to be functioning, 2 were definitely occluded.     

An unusual cause of thoracic outlet syndrome

In an adult with severe dysphagia, diagnosis of aneurysmal aberrant subclavian artery was suspected on computed tomogram; no vascular ring was visible on arteriogram. A diverticulum of the aortic isthmus was surgically resected. Histologic analysis ruled out acquired disease. In conclusion, dysphagia related to esophageal compression may be caused by an isolated congenital aortic diverticulum.     

Dorsal sympathectomy and management of thoracic outlet syndrome with VATS

Dorsal sympathectomy and the management of the thoracic outlet syndrome have been considerably improved with the use of video assistance because it affords both magnification and an improved light system. Two techniques of video assistance were employed in the group of patients described here. One involved the sympathectomy done through three ports using standard video-assisted thoracic surgical methods. The second technique involved a transaxillary incision with removal of the first rib using video-assistance magnification and light, operating either directly or secondarily while visualizing the image on the television set. (The vast majority of cases have been performed using this latter technique.) Major indications for performing dorsal sympathectomy include (1) hyperhidrosis, (2) Raynaud's phenomenon, (3) Raynaud's disease, (4) causalgia, (5) reflex sympathetic dystrophy, and (6) vascular insufficiency of the upper extremity. Except for hyperhidrosis, all of the other indications require the usual diagnostic techniques, including cervical sympathetic blockade to assess whether the symptoms are relieved by temporary blockade of the sympathetic ganglia. In 326 patients, sympathectomy, performed either alone or in conjunction with first-rib removal for relief of the thoracic outlet syndrome, has been successful. In only 6 patients has sympathetic activity recurred in less than 6 months. Initially all of them were treated conservatively. Three of the 6 required a repeat sympathectomy. Postsympathectomy neuralgia occurred in only 2 of more than 326 patients. Both cases were managed successfully in a conservative fashion. Among the patients in whom a Horner's syndrome was not deliberately induced, the syndrome developed in 2. In both, the syndrome resolved spontaneously within several months.     

The false-positive rate of thoracic outlet syndrome shoulder maneuvers in healthy subjects

Cytokines are considered as mediators of immune and inflammatory responses. Cisternal CSF levels of interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1) and of the soluble adhesion molecule E-selectin were evaluated in patients operated on for intracranial aneurysms. Cisternal CSF samples were obtained at surgery in 41 selected patients (31 with diagnosis of subarachnoid hemorrhage (SAH) and 10 control patients operated on for incidental unruptured aneurysms); 14 patients were operated within 72 h after SAH (early surgery) and 17 were operated after day 10 after the hemorrhage (delayed surgery). The CSF levels of cytokines were evaluated using radioimmunoassay and their concentrations were related to the timing of surgery, the amount of cisternal subarachnoid blood clots and the onset of clinical and angiographical evidence of arterial vasospasm. Mean cisternal CSF levels of IL-6, IL-8 and AMCP-1 are significantly higher in samples obtained from patients early operated after SAH, while levels of E-selectin were below the threshold value of the method in all 41 cases. In the early operated group 7 patients presented symptomatic vasospasm: levels of IL-8 and MCP-1 were not significantly different were compared to those of uncomplicated cases; on the other hand, significantly higher levels of IL-6 were shown in the subgroup of patients operated within 72 h after SAH and developing vasospasm. Among the patients undergoing delayed surgery 5 presented symptomatic vasospasm, but no significant difference was shown in cisternal CSF levels of cytokines measured. The results of the present study show that in patients with unruptured aneurysms cytokines are present in cisternal CSF in scarce quantities and that in subarachnoid spaces after SAH there is an impressive increase of IL-6, IL-8 and MCP-1. Moreover, the higher cisternal CSF levels of IL-6 found in the early stage after SAH might have a predictive value regarding the occurrence of symptomatic vasospasm.     

Conservative therapy in thoracic outlet syndrome. Literature review and pathogenetic considerations

Due to the broad clinical presentation and the lack of generally accepted diagnostic criteria, thoracic outlet syndrome (TOS) is a disputed diagnosis. Various surgical techniques have been described and investigated as treatment for TOS, whereas only a few studies have reported the outcome after a conservative approach. Based on the literature, the pathophysiology of TOS and the impact of conservative therapy are discussed. Our personal experience has shown that after early diagnosis and implementation this treatment is a safe and valuable therapeutical option in TOS based on the correction of a postural and functional disturbance of the upper thoracic aperture underlying the pathogenic process. Successful conservative treatment may also be considered as further diagnostic evidence for TOS.     

Dermatomal and mixed nerve somatosensory evoked potentials in the diagnosis of neurogenic thoracic outlet syndrome

To evaluate the diagnostic utility of dermatomal and mixed nerve somatosensory evoked potentials (SEPs) in patients with thoracic outlet syndrome (TOS) and to compare their value with routine electrodiagnostic methods, we studied a group of 44 patients with neurogenic TOS and 30 healthy controls. In addition to bilateral median and ulnar SEPs, evoked potentials were recorded after stimulation of C6 and C8 dermatomes from the first and fifth digits, respectively. The patients were classified into 3 groups according to the nature of their clinical condition. The abnormality rate for both ulnar and C8 dermatomal SEPs was 100% in a small group of patients with severe neurological signs like atrophy. In groups of patients with lesser degrees of neurogenic damage, abnormality rates for ulnar and C8 dermatomal SEPs on affected limb(s) were 67 and 50%, respectively. Same abnormality rates were 25 and 18% in patients with only subjective symptoms. In patients with objective neurological signs, the major increase in sensitivity was with electromyography (EMG). Abnormalities of routine nerve conduction studies and F-wave latency were observed in patients with severe neurogenic damage. We concluded that the most useful tests in the diagnosis of neurogenic TOS are needle EMG and ulnar SEPs.     

Computer-aided-instruction in the emergency department

The Massachusetts General Hospital Laboratory of Computer Science created a library of computer-aided-instruction (CAI) programs in 1972. An experimental network of Cai programs, made possible by National Library of Medicine (NLM) support, was set up in July 1972, operating over commercial communication lines. Programs developed by Massachusetts General, Ohio State University and the University of Illinois Medical College were made available to users with terminals in about 36 cities through a local telephone number. During the first two years of the program over 80 institutions participated. A trial of the Massachusetts General programs, in conjunction with the Continuing Education Committee of the American College of Emergency Physicians, was conducted in five representative community hospitals. The hospitals put up the cost of the terminals and the telephone charges. Results of the study showed that 12 of the 40 (30%) emergency physicians in the target population took 10 or more programs. They gave the programs a favorable overall rating--1.6 on a scale of 1 (strongly positive) to 5 (strongly negative).     

Quality improvement in the emergency department

A neonate born with a normal heart developed acute myocardial infarction at 12 days of age. Trivial mitral regurgitation secondary to fibrosis of posteromedial papillary muscle progressed to heart failure at 6 months of age. Mitral valve annuloplasty improved her condition.     

Computed tomography in the emergency department

We report a neonatal case of severe, life-threatening Kasabach-Merritt syndrome that was successfully treated with interferon-alpha: This patient had a huge hemangioma of the right leg and a general bleeding tendency. Although the condition initially responded to steroid and radiation therapy, after a relapse, no therapy including steroids, radiation, aspirin, and dipyridamole was effective. Because of severe thrombocytopenia and extension of the hemangioma to the pelvic region, surgical intervention was not indicated. Interferon-alpha therapy was started on day 61 of life. During the therapy the platelet counts increased by more than tenfold and reached the normal level in a month. The size of the hemangioma dramatically decreased. The administration of interferon-alpha might be indicated as a therapy for severe, life-threatening Kasabach-Merritt syndrome, especially when there is resistance to steroid or radiation therapy.     

Radiographic interpretation in the emergency department

This study examined the concordance of radiographic readings between emergency department (ED) attending physicians and radiologists in a community teaching hospital. In addition, the incidents of misinterpretations leading to an alteration in patient care were also reviewed. All radiographs obtained from January through October 1993 were initially interpreted by ED attending physicians with subsequent final review by attending radiology staff. Misread radiographs were placed into one of three categories. The groupings included overread radiographs with no change in treatment, underread radiographs with no change in treatment, and radiograph misinterpretations with a change in treatment. Of 15,585 radiographs obtained during the study period, there were 120 misreads; 12,099 (77.6%) of the 15,585 radiographs had an initial emergency physician interpretation. Radiographic misinterpretations included 7 (5.78%) overreads, 57 (47.1%) underreads, and 57 (47.51%) misreads requiring follow-up (MR-FU). The five most frequently misread radiographs were: abdominal, 12/247 (4.4%); rib, 3/99 (3.0%); foot, 13/621 (2.1%); hip, 3/152 (1.9%); and ankle 11/758 (1.4%). The most frequently obtained radiographs included: chest, 7,012 (0.33% MR-FU); cervical spine, 1,112 (0.18% MR-FU); ankle, 758 (0.66% MR-FU); knee, 633 (0.32% MR-FU); and foot, 621 (0.97% MR-FU). In this study, 99.0% of all emergency department radiographs were read correctly on initial review by ED attending physicians. Of all misread radiographs, less than half (46%) were deemed clinically significant and required a follow-up intervention.     

Evaluation of syncope in the emergency department

Treatment of acute myocardial infarction has evolved significantly in the past two decades. Reperfusion therapies of thrombolysis and percutaneous angioplasty are major advances that can be employed to save infarcting myocardium and reduce mortality. When reperfusion therapy is combined with the use of aspirin, beta-blockade, heparin, and nitroglycerin, the emergency management of the patient with myocardial infarction can be completed. Outcomes in patients are determined by what happens in the first few minutes to hours after onset, and any delay in diagnosis or treatment may have significant consequences. This article reviews intervention and treatment strategies for acute myocardial infarction.     

Thoracic outlet syndrome

A careful history and thorough physical examination are the most important components in establishing the diagnosis of TOS. The use of radiographic and laboratory tests, when indicated, can improve the diagnostic yield. Provocative positional maneuvers must be evaluated for their vascular and, more important, for their neurologic response. These maneuvers do not "make" the diagnosis, but they can be a useful adjunct for confirming the diagnosis. Vascular TOS is less common and often requires surgical treatment. Neurologic TOS is very common but less frequently requires surgical treatment. The surgical approach and procedure selection should be determined by the nature of the pathologic condition and site of compression.