Morbidity of First Rib Resection in the Surgical Repair of Thoracic Outlet Syndrome

Estimation of the prevalence of isolated inter-scalene compression from simultaneous arterial and venous photoplethysmography in patients referred for suspected thoracic outlet syndrome

Objective.In patients with suspected thoracic outlet syndrome (TOS), diagnosing inter-scalene compression could lead to minimally invasive treatments. During photo-plethysmography, completing a 30 s 90° abduction, external rotation ('surrender' position) by addition of a 15 s 90° antepulsion 'prayer' position, allows quantitative bilateral analysis of both arterial (A-PPG) and venous (V-PPG) results. We aimed at determining the proportion of isolated arterial compression with photo-plethysmography in TOS-suspected patients.Approach.We studied 116 subjects recruited over 4 months (43.3 ± 11.8 years old, 69% females). Fingertip A-PPG and forearm V-PPG were recorded on both sides at 125 Hz and 4 Hz respectively. A-PPG was converted to PPG amplitude and expressed as percentage of resting amplitude (% rest). V-PPG was expressed as percentage of the maximal value (% max) observed during the 'Surrender-Prayer' maneuver. Impairment of arterial inflow during the surrender (As+) or prayer (Ap+) phases were defined as a pulse-amplitude either <5% rest, or <25% rest. Incomplete venous emptying during the surrender (Vs+) or prayer (Vp+) phases were defined as V-PPG values either <70% max, or <87% max.Main results.Of the 16 possible associations of encodings, As - Vs - Ap - Vp- was the most frequent observation assumed to be a normal response. Isolated arterial inflow without venous outflow (As + Vs-) impairment in the surrender position was observed in 10.3% (95%CI: 6.7%-15.0%) to 15.1% (95%CI: 10.7%-20.4%) of limbs.Significance.Simultaneous A-PPG and V-PPG can discriminate arterial from venous compression and then potentially inter-scalene from other levels of compressions. As such, it opens new perspectives in evaluation and treatment of TOS.

Histologic evidence of brachial plexus compression sites at the thoracic inlet and variations in formation of the lower trunk in cadavers

BACKGROUND

In thoracic "outlet" syndrome (TOS), pathologic evidence is well documented for vascular but not neurologic compression. We hypothesized that histologic evidence of compression would be identified at sites where the upper trunk was impacted by the anterior scalene muscle and the lower trunk by anatomic anomalies or the first rib. The purpose of this study was to investigate this hypothesis in human cadavers.

MATERIALS AND METHODS

Twenty-five cadavers' brachial plexuses were dissected and excised. Histologic and descriptive analysis was directed at juncture 1, the upper trunk and anterior scalene muscle, and juncture 2, C8 and T1 nerve roots (lower trunk) with the posterior border of the first rib. Measurements were obtained at the juncture of the T1 nerve root with the C8 nerve root in relationship to the first rib.

RESULTS

Histologic analysis demonstrated epineurial and perineurial fibrosis, myelin thinning, and Renaut bodies at junctures 1 and 2. Lower trunk formation occurred on or lateral to the first rib in 66% of specimens, with asymmetry in 32% of cadavers. A muscle of Albinus was present in 18% of cadavers. A large dorsal scapular artery coursed through 36% of plexuses with a high, arched subclavian artery.

CONCLUSIONS

We report histologic changes consistent with chronic compression of the upper and lower plexus in the thoracic inlet at hypothesized sites of brachial plexus compression that may correlate with clinical neck/shoulder (upper trunk) and "ulnar nervelike" (C8-T1/lower trunk) symptoms. Anatomic anomalies identified should alert the surgeon to variations of lower trunk formation at compression sites.

Prevalence and anatomy of the anomalous subclavius posticus muscle and its clinical implications with emphasis in neurogenic thoracic outlet syndrome: Scoping review and meta-analysis

BACKGROUND

The subclavius muscle runs underneath the clavicle. However, there have been a few reports of a duplicated subclavius muscle which is commonly referred to as subclavius posticus muscle due to its orientation being posterior to the proper subclavius muscle. Its occurrence seems to potentially create a narrowing interval at the superior thoracic aperture as it crosses over the brachial plexus. It might also have functional influence on the shoulder girdle.

PURPOSE

To provide comprehensive gross anatomy description of the variant "subclavius posticus muscle" and to investigate its reported clinical implications with emphasis on its involvement in causing brachial plexus compression.

BASIC PROCEDURES

A scoping review with meta-analysis of the gross anatomy of the subclavius posticus muscle was conducted along with investigating its correlation to the thoracic outlet syndrome. Forty-seven articles were pooled through two rounds of the selection process. The relevant information was extracted and meta-analyzed.

MAIN FINDINGS

The scoping review and meta-analysis of the 47 articles revealed a total prevalence of 11/2069 (4.9%); 10/1369 (5.1%) in cadaveric studies, and 1/700 (5.0%) in MRI studies. The subclavius posticus muscle is a short triangular muscle with an average length of 12 cm and an average width of 1 cm. It originates from the sternal end of the first rib in most cases with reported variants of one case originating from the costoclavicular ligament and one case where it was fused with the proper subclavius muscle. Its insertion is more variable: on the superior border of the scapula with variable length in 71.35%, on the coracoid process of the scapula in 25.42%, and on the clavicle in 0.90%. The subclavian nerve seems to be the dominant nerve supply with a 57.6% prevalence, while 25.8% are innervated by the suprascapular nerve. Other reported nerves were the nerve to the myolohyoid (4.5%), accessory phrenic nerve (4.5%), and a direct branch from the brachial plexus (2.0%). The blood supply was reported (only once) to be from the suprascapular artery. However, the venous drainage was not established at all.

PRINCIPAL CONCLUSIONS

The subclavius posticus muscle is a variant muscle occurring with a reported overall prevalence of 4.9%. It can compress the brachial plexus as it runs across at the space of the superior thoracic aperture with exquisite contact, and this can lead to a neurogenic thoracic outlet syndrome. It also can be involved in the vascular thoracic outlet syndrome. Lastly, it is important not to omit its potential influence in shoulder joint instability to some extent.

Idiopathic upper extremity deep vein thrombosis: A systematic review

BACKGROUND

Idiopathic upper extremity deep vein thrombosis (UEDVT) management is controversial and ranges from anticoagulation alone to the addition of further interventions such as thrombolysis and decompressive surgery.

OBJECTIVES

The objective of this systematic review was to assess the effects of anticoagulation alone compared to anticoagulation with additional interventions such as thrombolysis or decompressive surgery on the incidence of recurrent UEDVT and post-thrombotic syndrome (PTS) in patients with idiopathic UEDVT (including those associated with the oral contraceptive pill).

PATIENTS/METHODS

A systematic search was conducted for studies which focused on acute UEDVT treatment defined as therapies starting within 4 weeks of symptom onset. We limited studies to those that recruited 10 or more subjects and involved at least 6 weeks to 12 months anticoagulation alone or together with additional interventions with at least 6-month follow-up. Primary outcomes were symptomatic recurrent radiologically confirmed UEDVT and PTS. Secondary outcomes were symptomatic venous thromboembolism, bleeding and mortality.

RESULTS

We found seven studies which reported recurrent UEDVT rates and five that reported PTS rates. All studies were retrospective or cross-sectional. None compared anticoagulation alone to anticoagulation with additional intervention. Study heterogeneity precluded meta-analysis and risk of bias was moderate to serious. Recurrent UEDVT occurred in 0% to 12% post-anticoagulation alone and 0% to 23% post-additional interventions. PTS rates varied from 4% to 32% without severe PTS. Only limited studies reported on our secondary outcomes.

CONCLUSION

There is limited evidence behind idiopathic UEDVT management. Prospective comparative studies in this area are essential.

Upper Extremity Deep Vein Thrombosis: Current Knowledge and Future Directions

Upper extremity deep vein thrombosis (UEDVT) has been increasing in incidence due to the escalating use of central venous catheters such as peripherally inserted central catheters. UEDVT can be primary idiopathic or secondary to pacemaker leads, intravascular catheters or cancer. In comparison to conventional venous thromboembolism such as lower limb deep vein thrombosis or pulmonary embolism the risk factors, investigations, and management are not well defined. We review current evidence in primary and secondary UEDVT, highlighting areas in need of further research. We also explore the entity of venous thoracic outlet syndrome, which is said to be a risk factor for recurrent primary UEDVT and is the rationale behind surgical interventions.

Supraclavicular Approach for Neurogenic Thoracic Outlet Syndrome: Description of a Learning Curve

BACKGROUND

The supraclavicular exposure represents an alternative approach for thoracic outlet decompression in neurogenic thoracic outlet syndrome with unique access to neurovascular structures. We aimed to evaluate the learning curve for this approach and associated patient outcomes.

METHODS

Patients undergoing first-time, unilateral, supraclavicular thoracic outlet decompression for neurogenic thoracic outlet syndrome were included. Cumulative-sum and linear-spline-regression analyses were used to determine the operative time learning curve. Patients were consecutively organized into early (learning phase) and late (competency) cohorts. Primary endpoints were the operative time learning curve operation number and association of this learning curve on differences in self-reported postoperative symptomatic improvement between early and late cohorts, adjusting for American Society of Anesthesiology classification, body mass index, previous treatment (opioid/neuropathic medication/botulinum-injection), and length of stay.

RESULTS

Among 114 patients, learning curve analyses showed decreasing operative times, plateauing at the 51st operation (ß = -1.63, 95% confidence interval [-2.30, -0.95], P < .001). No periprocedural differences existed between early (operations 1-50) and late (operations 51-114) cohorts. Self-reported 90-day outcomes were similar in early and late cohorts (odds ratio [OR]: 1.60 [0.65, 3.95], P = .31). Mediators of poor self-reported outcomes included increasing American Society of Anesthesiology classification (OR 0.21 [0.08, 0.54], P = .001), failed preoperative botulinum injection (OR 0.15 [0.03, 0.65], P = .01), and increased length of stay (OR 0.40 [0.22, 0.73], P = .003).

CONCLUSIONS

The learning curve for supraclavicular thoracic outlet decompression in neurogenic thoracic outlet syndrome occurred after 51 operations with a trend towards improved 90-day self-reported outcomes from the early to late phases. These findings, along with mediators of poorer outcomes, may aid surgeons in adopting a new approach and counseling patients on expected outcomes.

Measurement of Outlet Pressures Favors Rib Resection for Decompression of Thoracic Outlet Syndrome

BACKGROUND

When conservative therapy for thoracic outlet syndrome fails, scalenectomy with or without first-rib resection (FRR) is the treatment of choice. We measured pressure in the costoclavicular space before and after FRR at time of neurogenic thoracic outlet syndrome release to evaluate whether FRR is required to completely decompress the costoclavicular space.

METHODS

Using a supraclavicular exposure for anterior-middle scalenectomy with FRR, costoclavicular space pressures were measured using a balloon catheter with the patient's arm in neutral anatomic position, secondarily, the arm abducted and externally rotated. Pressures were recorded in both arm positions before scalenectomy, after scalenectomy, and after FRR. Paired Student's t test was used to compare differences in group means for paired samples. Patient-reported outcomes were reported using the Derkash classification and quick disabilities of the arm, shoulder, and hand (qDASH) questionnaire.

RESULTS

Fifteen patients (16 cases) surgically treated for neurogenic thoracic outlet syndrome were included in this retrospective study. There was no significant difference in pressure change between arm positions before scalenectomy (161.56 ± 71.65 mm Hg difference) or after scalenectomy (148.5 ± 80.24 mm Hg difference). There was a significant difference in pressure change between post-scalenectomy and post-FRR arm positions; mean pressure change between arm positions after FRR was 50.56 ± 40.28 mm Hg. Mean postoperative qDASH score was 20 ± 23.2. All patients reported improvement in symptoms and functional status.

CONCLUSIONS

Supraclavicular first rib resection for management of neurogenic thoracic outlet syndrome can be safely performed with favorable outcomes. The pressure increase in the costoclavicular space caused by arm abduction and external rotation was significantly reduced only after FRR, raising concerns about potential incomplete costoclavicular space decompression with scalenectomy alone for neurogenic thoracic outlet syndrome management.

Microvascular Response to the Roos Test Has Excellent Feasibility and Good Reliability in Patients With Suspected Thoracic Outlet Syndrome

Background: Exercise oximetry allows operator-independent recordings of microvascular blood flow impairments during exercise and can be used during upper arm provocative maneuvers.

Objective: To study the test-retest reliability of upper-limb oximetry during the Roos test in patients with suspected thoracic outlet syndrome (TOS).

Materials and Methods: Forty-two patients (28 men, 14 women; mean age: 40.8 years) were examined via transcutaneous oxygen pressure (TcpO2) recordings during two consecutive Roos tests in the standing position. The minimal decrease from rest of oxygen pressure (DROPmin) value was recorded after each maneuver was performed on both arms. The area under the receiver operating characteristic (ROC) curve defined the DROPmin diagnostic performance in the presence of symptoms during the tests. The Mann–Whitney U-test was used to compare the DROPmin in the symptomatic vs. asymptomatic arms. The test-retest reliability was analyzed with Bland-Altman representations. The results are presented as means ± standard deviations (SD) or medians [25–75 percentiles].

Results: The symptoms by history were different from the symptoms expressed during the Roos maneuvers in one-third of the patients. The DROPmin measurements were −19 [−36; −7] mmHg and −8 [−16; −5] mmHg in the symptomatic (n = 108) and asymptomatic (n = 60) arms, respectively. When TOS observed on ultrasound imaging was the endpoint, the area under the ROC curve (AUC) was 0.725 ± 0.058, with an optimal cutoff point of −15 mmHg. This value provided 67% sensitivity and 78% specificity for the presence TOS via ultrasound. When symptoms occurring during the test represented the endpoint, the AUC was 0.698 ± 0.04, with a cutoff point of −10 mmHg. This provided 62% sensitivity and 66% specificity for the presence of pain in the ipsilateral arm during the test. The test-retest reliability of DROPmin proved to be good but not perfect, partly because of unreliability of the provocation maneuvers.

Conclusion: To the best of our knowledge, this study is the first to investigate microvascular responses during the Roos maneuver in patients with suspected TOS. The presence of symptoms was significantly associated with ischemia. TcpO2 facilitated the recording of both macrovascular and microvascular responses to the Roos test. The Roos maneuver should probably be performed at least twice in patients with suspected TOS.