Quadrilateral space syndrome caused by a humeral osteochondroma: a case report and review of literature

Axillary and musculocutaneous neuropathies

This chapter covers axillary and musculocutaneous neuropathies, with a focus on clinically relevant anatomy, electrodiagnostic approaches, etiologic considerations, and management principles. Disorders of the lateral antebrachial cutaneous nerve, a derivative of the musculocutaneous nerve, are also reviewed. We emphasize the importance of objective findings, including the physical examination and electrodiagnostic evaluation in confirming the isolated involvement of each nerve which, along with the clinical history, informs etiologic considerations. Axillary and musculocutaneous neuropathies are both rare in isolation and most frequently occur in the setting of trauma. Less commonly encountered etiologies include external compression or entrapment, neoplastic involvement, or immune-mediated disorders including neuralgic amyotrophy, postsurgical inflammatory neuropathy, multifocal motor neuropathy, vasculitic neuropathy, and multifocal chronic inflammatory demyelinating polyradiculoneuropathy.

Quadrilateral space syndrome induced by a large degenerative osteophyte

A 41-year-old gentleman presented with decreased range of motion. Initial radiographs demonstrated extensive osteoarthritic changes involving the glenohumeral joint with a large inferior oriented osteophyte. Subsequent MRI of the shoulder was obtained which demonstrated isolated fatty atrophy of the teres minor and, to a lesser extent, deltoid muscles. The axillary nerve was visualized entering the quadrilateral space which, although, was severely narrowed secondary to the large osteophyte. The patient's clinical symptoms and MRI findings were consistent with quadrilateral space syndrome. The patient wanted to attempt conservative therapy first; and therefore, subsequently underwent physical therapy with improvement of shoulder strength and range of motion.

Musculoskeletal ultrasound diagnosis of quadrilateral space syndrome: A case report

INTRODUCTION

Quadrilateral space syndrome (QSS) is a peripheral nerve entrapment disease, which can be misdiagnosed in clinic. In the past, QSS was mainly diagnosed by clinical symptoms combined with magnetic resonance imaging (MRI), electromyography (EMG), and arterial angiography. There are few reports on the diagnosis of QSS by musculoskeletal ultrasound (MSKUS) combined with clinical symptoms.

PATIENT CONCERNS

A middle-aged female patient had posterolateral pain and numbness in her right shoulder for 2 months.

DIAGNOSES

At first, she was diagnosed as suprascapular nerve entrapment, while EMG of suprascapular nerve and axillary nerve indicated that nerve conduction was normal. Then, MRI was performed, showing the shoulder had no abnormalities, and EMG and arterial angiography of upper limb showed no abnormalities too. Finally, she was diagnosed as QSS according to MSKUS and lidocaine block test.

INTERVENTIONS

Two sealing treatments of axillary nerve block in quadrilateral space under the guidance of MSKUS were performed.

OUTCOMES

After 2 treatments, the pain and numbness in her shoulder disappeared, and her shoulder could move normally. There was no recurrence after 3 months of follow-up.

CONCLUSION

MSKUS is an effective method to diagnose QSS. It is fast, convenient and inexpensive, and is worth popularizing in clinic.

Clinico-radiological review of peripheral entrapment neuropathies - Part 1 upper limb

PURPOSE

This article aims to review the pertinent anatomy, etiopathogenesis, current clinical and radiological concepts and principles of management in case of upper limb entrapment neuropathies.

METHODS

The review is based on critical analysis of the existing literature as well as our experience in dealing with entrapment neuropathies.

RESULTS

Entrapment neuropathies of the upper limb peripheral nerves are common conditions that are often misdiagnosed because of their varying clinical presentations and lack of standardized diagnostic methods. Clinical assessment and electrodiagnostic studies have been the mainstay; however, imaging techniques have provided newer insights into the pathophysiology of these entities, leading to a paradigm shift in their diagnosis and management. The current best practice protocols for entrapment syndromes are constantly evolving with increasing emphasis on the role high-resolution ultrasound and magnetic resonance imaging. Many imaging criteria are described and we have tried to present the most validated measurements for diagnosing entrapment neuropathies.

CONCLUSION

It is imperative for a clinical radiologist to be familiar with the etiopathogenesis and clinical features of these conditions, in addition to being thorough with the anatomy and the latest imaging strategies.

Current concepts review: peripheral neuropathies of the shoulder in the young athlete

Peripheral neuropathies of the shoulder and upper extremity are uncommon injuries that may affect the young athletic population. When present, they can result in significant pain and functional impairment. The cause of peripheral neuropathy in young athletes may be an acute, traumatic injury such as a shoulder dislocation or a direct blow to the shoulder girdle. Alternatively, repetitive overuse with resultant compression or traction of a nerve over time may also result in neuropathy; overhead athletes and throwers may be particularly susceptible to this mechanism of nerve injury. Regardless of etiology, young athletes typically present with activity-related pain, paresthesias, and dysfunction of the affected upper extremity. In addition to physical examination, diagnostic studies such as radiographs and magnetic resonance imaging (MRI) are commonly performed as part of an initial evaluation and electrodiagnostic studies may be used to confirm the diagnosis of peripheral neuropathy. Electrodiagnostic studies may consist of electromyography, which evaluates the electrical activity produced by skeletal muscles, and/or a nerve conduction study, which evaluates a nerve's ability to transmit an electrical signal. Although data are not robust, clinical outcomes for young patients with activity-related peripheral neuropathies of the shoulder are generally good, with most young athletes reporting both symptomatic and functional improvement after treatment.

Quadrilateral space syndrome: The forgotten differential

The quadrilateral space is bounded by the teres minor superiorly, the teres major inferiorly, the long head of the triceps medially and the shaft of the humerus laterally. The axillary nerve and posterior circumflex humeral artery pass through this space to enter the posterior compartment of the upper arm. Quadrilateral space syndrome (QSS) is caused by entrapment of the axillary nerve or its main branches and/or the posterior circumflex humeral artery in the quadrilateral space by internal or external compression. QSS can often be difficult to diagnose, given that patients may present with non-specific symptoms. As such, patients may be misdiagnosed with more common disorders of the shoulder. We report a case of QSS masquerading initially as rotator cuff pathology with positive impingement signs.

Fluoroscopic-guided quadrilateral space block for the treatment of quadrilateral space syndrome - A case report

We report a case of a 48-year-old female who presented four months following a low-energy trauma with symptoms most consistent with adhesive capsulitis. An MRI demonstrated extensive patchy areas of intramuscular edema-like signal involving the lateral head of the deltoid with associated muscle atrophy, in keeping with a subacute denervation injury. She was diagnosed with quadrilateral space syndrome (QSS) and successfully treated with an fluoroscopic-guided corticosteroid injection. At her two-year follow-up, the patient had regained full function and had no lasting symptoms. Non-specific symptoms like ill-defined shoulder pain, decreased motor function, and weakness can delay the diagnosis and management of QSS. As there is a lack of a good diagnostic study, fluoroscopic-guided quadrilateral space block should be considered should the diagnosis fit a patient's clinical profile, as this has the potential to be both diagnostic and therapeutic.

Quadrilateral space syndrome: a review

Quadrilateral space (QS) syndrome (QSS) is a relatively rare condition in which the axillary nerve and the posterior humeral circumflex artery are compressed within the QS. Fibrous bands are most commonly implicated as the cause, with true space-occupying lesions being less common. QSS is characterized by poorly localized shoulder pain and paresthesia over the lateral aspect of the shoulder and arm in a nondermatomal pattern. These symptoms are aggravated by shoulder abduction and external rotation. Point tenderness is typically present over the QS; however, diagnosis on physical examination can be difficult. Pain relief after lidocaine block of the axillary nerve within the QS is a useful finding in the evaluation of patients with suspected QSS. No definitive diagnostic imaging exists, making diagnosis difficult, although radiographs and magnetic resonance imaging are recommended to rule out other pathology. Nonoperative treatment, including nonsteroidal anti-inflammatory drugs, activity modification, and physical therapy, for at least 6 months is recommended before pursuing operative intervention. Small case series have shown that surgical decompression of the QS has good outcomes, with resolution of pain and return to sport.

Quadrilateral Space Syndrome: Diagnosis and Clinical Management

Quadrilateral space syndrome (QSS) is a rare disorder characterized by axillary nerve and posterior humeral circumflex artery (PHCA) compression within the quadrilateral space. Impingement is most frequently due to trauma, fibrous bands, or hypertrophy of one of the muscular borders. Diagnosis can be complicated by the presence of concurrent traumatic injuries, particularly in athletes. Since many other conditions can mimic QSS, it is often a diagnosis of exclusion. Conservative treatment is often first trialed, including physical exercise modification, physical therapy, and therapeutic massage. In patients unrelieved by conservative measures, surgical decompression of the quadrilateral space may be indicated.

Understanding the Hill-Sachs Lesion in Its Role in Patients with Recurrent Anterior Shoulder Instability

PURPOSE OF REVIEW

The purpose of this study is to provide an update to the orthopedic field in regard to treatment of the Hill-Sachs lesion and anterior shoulder instability. The review highlights the most current knowledge of epidemiology, clinical evaluation, and surgical methods used to treat Hill-Sachs lesions. It also details the relevant clinical and surgical findings that have been made throughout the literature in the past couple of years.

RECENT FINDINGS

The most recent literature covering the Hill-Sachs lesion has focused on the relatively new and unexplored topic of the importance of concomitant injuries while treating a humeral head defect. The glenoid track concept has been clinically validated as a method to predict engagement. 3D-CT has become the "gold standard" for Hill-Sachs imaging; however, it has been noted that 3D-MRI produces results that are not significantly different from CT. Also, it has been found that when the arm is in a position of abduction during the primary injury, there is a higher risk of engagement and subsequent dislocation. Recent studies have demonstrated successful results stemming from purely arthroscopic procedures in treating Hill-Sachs lesions. Anterior shoulder instability, specifically the Hill-Sachs lesion, is an area of orthopedic study that is highly active and constantly producing new studies in an attempt of gaining the best outcomes for patients. The past few years have yielded many excellent discoveries, but there is still much more work to be done in order to fully understand the role of the Hill-Sachs lesion in anterior shoulder instability.

Accessory subscapularis muscle - A forgotten variation?

The quadrangular space is a space in the axilla bounded by the inferior margin of the teres minor muscle, the superior margin of the teres major muscle, the lateral margin of the long head of the triceps brachii muscle and the surgical neck of the humerus, medially. The axillary nerve (C5-C6) and the posterior circumflex humeral artery and veins pass through this space in order to supply their territories. The subscapularis muscle is situated into the scapular fossa and inserts itself into the lesser tubercle of the humerus, thus helping stabilize the shoulder joint. A supernumerary muscle known as accessory subscapularis muscle originates from the anterior surface of the muscle and usually inserts itself into the shoulder joint. It is a rare variation with few reports of its existence and incidence. We present a case of the accessory subscapularis muscle in a male cadaver fixated with a 10% formalin solution. The muscle passed anteriorly to the axillary nerve, thus, predisposing an individual to quadrangular space compression syndrome. We perform a review of the literature and address its clinical, anthropological and anatomical significance.

Quadrilateral space syndrome: the Mayo Clinic experience with a new classification system and case series

Quadrilateral space syndrome (QSS) arises from compression or mechanical injury to the axillary nerve or the posterior circumflex humeral artery (PCHA) as they pass through the quadrilateral space (QS). Quadrilateral space syndrome is an uncommon cause of paresthesia and an underdiagnosed cause of digital ischemia in overhead athletes. Quadrilateral space syndrome can present with neurogenic symptoms (pain and weakness) secondary to axillary nerve compression. In addition, repeated abduction and external rotation of the arm is felt to lead to injury of the PCHA within the QSS. This often results in PCHA thrombosis and aneurysm formation, with distal emboli. Because of relative infrequency, QSS is rarely diagnosed on evaluation of athletes with such symptoms. We report on 9 patients who presented at Mayo Clinic with QSS. Differential diagnosis, a new classification system, and the management of QSS are discussed, with a comprehensive literature review. The following search terms were used on PubMed: axillary nerve, posterior circumflex humeral artery, quadrilateral space, and quadrangular space. Articles were selected if they described patients with symptoms from axillary nerve entrapment or PCHA thrombosis, or if related screening or imaging methods were assessed. References available within the obtained articles were also pursued. There was no date or language restriction for article inclusion; 5 studies in languages besides English were reported in German, French, Spanish, Turkish, and Chinese.

Teres minor muscle and related anatomy

BACKGROUND

The purpose of this study was to describe the complex anatomy surrounding the teres minor muscle.

METHODS

Thirty-one cadaveric human shoulders were dissected. Qualitative fascial and neurovascular anatomy were described. Location of motor nerves to teres minor were measured in reference to local anatomy.

RESULTS

Fascial anatomy of the posterior shoulder had 2 distinct and equally common variants, 1 of which demonstrated a stout, inflexible fascial compartment enveloping the teres minor muscle. The other had a continuous fascia enveloping both the infraspinatus and teres minor muscles. In both variants, the primary nerve to teres minor traveled around a fascial sling, becoming sub-fascial at an average of 44 mm (range, 25-68) medial to the teres minor's insertion. The nerve took its most angulated course as it entered the fascial sling. Smaller accessory innervation of teres minor began, on average, 30 mm (range, 15-48) medial to the muscle's lateral insertion. None of the accessory motor nerves coursed deep to the fascial sling nor to the distinct teres minor fascial compartment.

CONCLUSION

A stout fascial sling may be the potential site of greatest compression and tethering of the primary motor nerve to teres minor. Additional lateral accessory motor nerves to teres minor remained extra-fascial and took a less angulated path. Half of the shoulders demonstrated a separate teres minor fascial compartment. An improved understanding of the fascial anatomy and innervation pattern of the teres minor muscle may help clinicians who treat patients with symptomatic isolated teres minor muscle atrophy.

Arthroscopic trans-capsular axillary nerve decompression: indication and surgical technique

Symptomatic axillary nerve compression is rare yet results in debilitating pain, weakness, and decreased athletic performance in some patients. If nonoperative modalities fail, surgical intervention is necessary to reduce symptoms and avoid functional decline. Traditionally, open techniques have been described to decompress the axillary nerve and are reported to provide satisfactory results. Similar to suprascapular nerve decompression, recent advances have provided the opportunity to develop all-arthroscopic axillary nerve decompression techniques. Although direct comparisons between open and arthroscopic techniques do not exist, arthroscopic axillary nerve decompression may provide some benefits over open techniques. Therefore we present a technique and early results for all-arthroscopic trans-capsular axillary nerve decompression.