Impact of Scalene Muscle Botulinum Toxin Injection With and Without Surgery in Neurogenic Thoracic Outlet Syndrome

Thoracic Outlet Syndrome

ABSTRACT

Thoracic outlet syndrome is a complex syndrome that manifests with symptoms based on the presumed injury or impairment of the neurovascular structures in the thoracic outlet space with its intricate anatomy and pathophysiology. The thoracic outlet is a specific anatomical region with three distinct anatomical spaces - interscalene triangle, the costoclavicular space, and the retro-pectoralis minor space. Thoracic outlet syndrome is classified into neurogenic, venous, and arterial thoracic outlet syndrome and often poses diagnostic challenge to implicate a specific condition or cause. Many cases of thoracic outlet syndrome can be effectively managed through conservative measures, but patients with refractory symptoms may warrant surgical intervention. Modalities such as intramuscular anesthetic and botulinum toxin injections hold promise as diagnostic, therapeutic, and prognostic procedures. Further research and collaboration are needed to develop algorithms for diagnosis and treatment of thoracic outlet syndrome symptoms. This review aims to explore our understanding of thoracic outlet syndrome, with a focus on current evidence and emerging trends.

Sports-related peripheral nerve injuries of the upper limb

Peripheral nerve injuries in athletes affect the upper limb more commonly than the lower limb. Common mechanisms include compression, traction, laceration, and ischemia. Specific sports can have unique mechanisms of injury and are more likely to be associated with certain neuropathies. Familiarity with these sport-specific variables and recognition of the common presentations of upper limb neuropathic syndromes are important in assessing an athlete with a suspected peripheral nerve injury. Evaluation may require imaging modalities and/or electrodiagnostic testing to confirm a nerve injury. In some cases, diagnostic injections may be needed to differentiate neuropathic versus musculoskeletal etiology. Early and accurate diagnosis is essential for treatment/management and increases the likelihood of a safe return-to-sport and avoidance of long-term functional consequences. Most nerve injuries can be treated conservatively, however, severe or persistent cases may require surgical intervention. This monograph reviews key diagnostic, management, and preventative strategies for sports-related peripheral nerve injuries involving the upper limb.

Diagnosis and management of thoracic outlet syndrome in athletes

The physical demands of sports can place patients at elevated risk of use-related pathologies, including thoracic outlet syndrome (TOS). Overhead athletes in particular (eg, baseball and football players, swimmers, divers, and weightlifters) often subject their subclavian vessels and brachial plexuses to repetitive trauma, resulting in venous effort thrombosis, arterial occlusions, brachial plexopathy, and more. This patient population is at higher risk for Paget-Schroetter syndrome, or effort thrombosis, although neurogenic TOS (nTOS) is still the predominant form of the disease among all groups. First-rib resection is almost always recommended for vascular TOS in a young, active population, although a surgical benefit for patients with nTOS is less clear. Practitioners specializing in upper extremity disorders should take care to differentiate TOS from other repetitive use-related disorders, including shoulder orthopedic injuries and nerve entrapments at other areas of the neck and arm, as TOS is usually a diagnosis of exclusion. For nTOS, physical therapy is a cornerstone of diagnosis, along with response to injections. Most patients first undergo some period of nonoperative management with intense physical therapy and training before proceeding with rib resection. It is particularly essential for ensuring that athletes can return to their baselines of flexibility, strength, and stamina in the upper extremity. Botulinum toxin and lidocaine injections in the anterior scalene muscle might predict which patients will likely benefit from first-rib resection. Athletes are usually satisfied with their decisions to undergo first-rib resection, although the risk of rare but potentially career- or life-threatening complications, such as brachial plexus injury or subclavian vessel injury, must be considered. Frequently, they are able to return to the same or a higher level of play after full recovery.

Role of Lifestyle in Thoracic Outlet Syndrome: A Narrative Review

INTRODUCTION

The presence of a positional compression of the neurovascular bundle in the outlet between the thorax and the upper limb during arm movements (mainly abduction) is common but remains asymptomatic in most adults. Nevertheless, a certain number of subjects with thoracic outlet positional compression will develop incapacitating symptoms or clinical complications as a result of this condition. Symptomatic forms of positional neurovascular bundle compression are referred to as "thoracic outlet syndrome" (TOS).

MATERIALS AND METHODS

This paper aims to review the literature and discuss the interactions between aspects of patients' lifestyles in TOS. The manuscript will be organized to report (1) the historical importance of lifestyle evolution on TOS; (2) the evaluation of lifestyle in the clinical routine of TOS-suspected patients, with a description of both the methods for lifestyle evaluation in the clinical routine and the role of lifestyle in the occurrence and characteristics of TOS; and (3) the influence of lifestyle on the treatment options of TOS, with a description of both the treatment of TOS through lifestyle changes and the influence of lifestyle on the invasive treatment options of TOS.

RESULTS

We report that in patients with TOS, lifestyle (1) is closely related to anatomical changes with human evolution; (2) is poorly evaluated by questionnaires and is one of the factors that may induce symptoms; (3) influences the sex ratio in symptomatic athletes and likely explains why so many people with positional compression remain asymptomatic; and (4) can sometimes be modified to improve symptoms and potentially alter the range of interventional treatment options available.

CONCLUSIONS

Detailed descriptions of the lifestyles of patients with suspected TOS should be carefully analysed and reported.

Possible role of the botulinum toxin in the management of neurogenic thoracic outlet syndrome: a systematic review

INTRODUCTION

Thoracic outlet syndrome (TOS) is related to the compression and/or the traction of the upper-limb neurovascular bundle, responsible for a chronic painful impairment. Neurogenic TOS (NTOS) is the most common manifestation. It remains a challenging diagnosis and its treatment is also difficult. Botulinum toxin (BTX) has been described to help both the diagnosis and the symptoms improvement.

EVIDENCE ACQUISITION

A systematic literature research was performed using PubMed, ScienceDirect, and Embase databases to collect studies reporting the use of BTX in NTOS management. We followed the PRISMA guidelines, and the included studies were evaluated using the GRADE approach.

EVIDENCE SYNTHESIS

We included 10 original articles representing 555 patients. Various outcomes were considered, and results varied from a study to another. Symptoms relief varied from an absence of BTX effectiveness to 84.1% of improvement; relief duration was also reported from none to 88 days. BTX injections were debatable predictors of surgical procedure successes due to low evidence. There was a huge gap between the studies concerning side-effects of the BTX procedures, from none to 100% of the patients.

CONCLUSIONS

There is no evidence for considering BTX injection as a validated tool for the management of NTOS. There might be a slight effect on symptoms, but outcomes are very variable, which prevents further interpretations. The use of BTX should be evaluated in larger prospective cohorts with more standardized outcomes.