Ulnar nerve entrapment at the wrist

A systematic review of steroid use in peripheral nerve pathologies and treatment

Background

The use of corticosteroids has become a part of the standard of care in various pathologies but their use in peripheral nerve injury treatment is limited. Given corticosteroids' anti-inflammatory properties and their regulatory role in neuronal protein production and myelination, corticosteroids could serve as an adjunct therapy for peripheral nerve injuries. This review aims to systematically investigate the current use of corticosteroid treatment in peripheral nerve pathologies.

Methods

The systematic search was performed on PubMed, MEDLINE, EMBASE, Scopus, Cochrane, and Web of Science using keywords such as "corticosteroid treatment," "peripheral nerve damage," "peripheral neuropathy," and "complications." The PRISMA guidelines were used to conduct the systematic review and all articles were reviewed by the corresponding author. After the initial search, individual study titles and abstracts were further screened and categorized using an inclusion and exclusion criteria followed by a final full-text review.

Results

Out of the total 27,922 identified records, 203 studies were included based on the selection criteria. These studies focused on the use and efficacy of steroids across a spectrum of compression and non-compression peripheral neuropathies such as cubital tunnel syndrome and chronic inflammatory demyelinating polyradiculoneuropathy. Various studies noted the promising role of steroids in offering pain relief, nerve block, and nerve regeneration effects. Additionally, safety considerations and potential complications regarding steroid use in peripheral nerve injuries were analyzed.

Conclusion

While there is currently limited clinical utilization of corticosteroids in peripheral nerve pathologies, the anti-inflammatory and regenerative effects that steroids provide may be a beneficial tool in managing various peripheral neuropathies and their associated pain. Additional clinical trials and investigation into the mechanism of action could improve the reputation of steroid use as peripheral nerve injury treatment.

[Rare nerve compression neuropathies]

UNCOMMON NERVE COMPRESSION SYNDROMES

In regard to the complex anatomical relationship of peripheral nerves and muscles, tendons, fasciae as well as their long course within those anatomical structures and additional close contact to bony structures, they are prone to suffer from local compression syndromes. Hence creating a vast majority of entrapment syndromes - well described in literature for almost every single nerve. The purpose of this article is to give an overview of symptoms, signs, diagnostic studies and treatment options, addressing especially the less known syndromes. Compression syndromes of the upper arm and shoulder region include the suprascapular nerve syndrome the compression of the axillary nerve within the spatium quadrilaterale and the compression of the long thoracic nerve at the chest wall. The upper extremity offers a variety of infrequent entrapment syndromes, as the pronator teres syndrome and anterior interosseus syndrome, both resulting from pressure to the median nerve in the forearm. Compression neuropathy in the course of the radial nerve in the distal upper extremity is also known as supinator syndrome. Guyon's canal syndrome is the ulnar side equivalent to the well-known carpal tunnel syndrome. In the case of a Cheiralgia paresthetica, a compression of a sensory branch of the superficial radial nerve can be seen. In the lower extremities, a variety of nerves especially in the groin and thigh area can be compressed as they pass through the narrow spaces between the abdominal muscles or underneath the inguinal ligament. Compression of the lateral femoral cutaneous nerve is the most common syndrome. Compression syndromes of the femoral and obturator nerves are most often iatrogenic. Pain around the knee, especially the lateral part and following orthopedic procedures of the knee, can arise from a compression or a lesion of a small infrapatellar branch of the saphenous nerve. Another probably underdiagnosed syndrome is piriformis syndrome, resulting from an entrapment of the sciatic nerve as it passes through certain muscular structures. In the distal lower extremity, the peroneal and tibial nerves can be compressed at multple sites, clinically known as peroneal nerve paralysis resulting from nerve compression around the fibular head, the anterior and posterior tarsal tunnel syndrome, and Morton's metatarsalgia.

Nerve Imaging in the Wrist

Neuropathic symptoms involving the wrist are a common clinical presentation that can be due to a variety of causes. Imaging plays a key role in differentiating distal nerve lesions in the wrist from more proximal nerve abnormalities such as a cervical radiculopathy or brachial plexopathy. Imaging complements electrodiagnostic testing by helping define the specific lesion site and by providing anatomical information to guide surgical planning. This article reviews nerve anatomy, normal and abnormal findings on ultrasonography and magnetic resonance imaging, and common and uncommon causes of neuropathy.

Characteristics of surgically treated Guyon canal syndrome: A multicenter retrospective study

Guyon canal (GC) syndrome is a rare peripheral neuropathy involving the distal part of the ulnar nerve. Several causes are associated with GC syndrome, including anatomic variations, space-occupying tumors, and trauma. Because of disease rarity, the only reported studies of GC syndrome are case series with small sample size. We conducted a multicenter study to identify the basic characteristics of patients with surgically treated GC syndrome and the risk factors for the disease. This retrospective multicenter study was conducted between January 2001 and December 2020. We screened 70 patients who underwent GC release surgery by seven hand surgeons at six institutes. A total of 56 patients were included in this study, including 38 patients (67.9%) who underwent isolated GC decompression and 18 (32.1%) who underwent combined peripheral nerve decompression. The mean patient age was 48.4 years (range: 20-89 years), and 40 patients (71.4%) were male. The average preoperative symptom duration was 18.5 months, and most patients were office workers. Ultrasound was positive for GC syndrome in 7/10 patients evaluated, CT in 2/5, MRI in 17/23, and electrodiagnostic studies in 35/44. The most common cause of GC syndrome was tumor (n = 23), followed by idiopathic (n = 17), trauma (n = 12), anatomic variants (n = 3), and inflammation (n = 3). In conclusion, most patients with GC syndrome in this study were male and had symptoms in one wrist. The most common cause of GC syndrome in this study was a tumor, including a ganglion cyst. Level of Evidence: Level IV case series.

Reliability of deep branch of ulnar nerve identification in interosseous-to-ulnar motor nerve transfer: A cadaver study of 20 wrists

Reinnervation of the intrinsic hand muscles after proximal ulnar nerve repair is often unsatisfactory. Promising results have nevertheless been reported recently for supercharged end-to-side anterior interosseous to deep branch of the ulnar nerve (DBUN) transfer. The aim of this study was to determine whether the DBUN can be reliably identified without retrograde intraneural dissection from Guyon's canal. Twenty cadaveric wrists were dissected. In a first stage, nerve transfer was performed through a limited 4 cm incision without releasing Guyon's canal. In a second stage, correct identification of the DBUN was assessed by retrograde intraneural dissection from its point of exit from Guyon's canal. The DBUN was correctly identified in 18 of the 20 wrists (90%). Although anatomical landmarks provide valuable clues, identifying the DBUN by neurolysis is technically challenging. All the elements required for nerve transfer can be exposed through a 4 cm incision, but the DBUN was nevertheless incorrectly identified in 10% of cases. Guyon canal release seems advisable to guarantee correct DBUN identification.

Electrodiagnosis of Common Mononeuropathies: Median, Ulnar, and Fibular (Peroneal) Neuropathies

This article addresses common mononeuropathies seen in the electrodiagnostic laboratory. The most common mononeuropathies-median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, and fibular (peroneal) neuropathy at the fibular head-are reviewed. The causes, clinical presentations, approached to the electrodiagnostic studies (including nerve conduction studies and needle electromyography), and the typical findings are discussed.

Acute Ulnar Neurapraxia and Carpal Tunnel Syndrome in the Context of a Distal Radius Fracture

Distal radius fractures, carpal tunnel syndrome, and ulnar nerve compression are common causes of symptoms that result in patients presenting for hand evaluation. This is a unique case of a distal radius fracture leading to both carpal tunnel syndrome and ulnar nerve compression requiring urgent operative management.

Cycling-Related Compressive Neuropathy of the Deep Ulnar Motor Branch in the Hand: Is Sonography a Valid Tool?

Repetitive vibratory trauma in cyclists is one of the most common causes of ulnar nerve compression at the wrist. This study describes five cases of clinically suspected compression syndrome of the deep terminal branch of the ulnar nerve (DBUN) defined by high-resolution ultrasound (HRUS) with a 18-MHz linear transducer. Reliable HRUS visualization of the DBUN was feasible in all patients. The affected nerves had focally swollen and hypo-echoic changed segments. HRUS is a good imaging tool for the evaluation of a suspicious DBUN neuropathy if no electrodiagnostic testing is available or in patients with mild to moderate clinical symptoms with inconclusive electrodiagnostic results.

Revision Peripheral Nerve Surgery of the Upper Extremity

Peripheral nerve injuries of the upper extremity can result from a wide array of etiologies, with the two most common being compression neuropathy and traumatic injuries. These types of injuries are common and can be psychologically, functionally, and financially devastating to the patient. A detailed preoperative evaluation is imperative for appropriate management. Traumatic injuries can typically be treated with local burial techniques, targeted muscle reinnervation, and regenerative peripheral nerve interfaces. Median nerve compression is frequently managed with complete release of the antebrachial fascia/transverse carpal ligament and/or use of flap coverage such as the hypothenar fat pad flap and local muscle flaps. Ulnar nerve compression is commonly managed via submuscular transposition, subcutaneous transposition, neurolysis, and nerve wrapping. In this review, we discuss the preoperative evaluation, surgical techniques, and advantages and disadvantages of each treatment modality for patients with compressive and traumatic upper extremity nerve injuries.

An Update on Treatment Modalities for Ulnar Nerve Entrapment: A Literature Review

CONTEXT

Ulnar nerve entrapment is a relatively common entrapment syndrome second only in prevalence to carpal tunnel syndrome. The potential anatomic locations for entrapment include the brachial plexus, cubital tunnel, and Guyon's canal. Ulnar nerve entrapment is more so prevalent in pregnancy, diabetes, rheumatoid arthritis, and patients with occupations involving periods of prolonged elbow flexion and/or wrist dorsiflexion. Cyclists are particularly at risk of Guyon's canal neuropathy. Patients typically present with sensory deficits of the palmar aspect of the fourth and fifth digits, followed by motor symptoms, including decreased pinch strength and difficulty fastening shirt buttons or opening bottles.

EVIDENCE ACQUISITION

Literature searches were performed using the below MeSH Terms using Mendeley version 1.19.4. Search fields were varied until further searches revealed no new articles. All articles were screened by title and abstract. Decision was made to include an article based on its relevance and the list of final articles was approved three of the authors. This included reading the entirety of the artice. Any question regarding the inclusion of an article was discussed by all authors until an agreement was reached.

RESULTS

X-ray and CT play a role in diagnosis when a bony injury is thought to be related to the pathogenesis (i.e., fracture of the hook of the hamate.) MRI plays a role where soft tissue is thought to be related to the pathogenesis (i.e., tumor or swelling.) Electromyography and nerve conduction also play a role in diagnosis. Medical management, in conjunction with physical therapy, shows limited promise. However, minimally invasive techniques, including peripheral percutaneous electrode placement and ultrasound-guided electrode placement, have all been recently studied and show great promise. When these techniques fail, clinicians should resort to decompression, which can be done endoscopically or through an open incision. Endoscopic ulnar decompression shows great promise as a surgical option with minimal incisions.

CONCLUSIONS

Clinical diagnosis of ulnar nerve entrapment can often be delayed and requires the suspicion as well as a thorough neurological exam. Early recognition and diagnois are important for early institution of treatment. A wide array of diagnostic imaging can be useful in ruling out bony, soft tissue, or vascular etiologies, respectively. However, clinicians should resort to electrodiagnostic testing when a definitive diagnois is needed. Many new minimally invasive techniques are in the literature and show great promise; however, further large scale trials are needed to validate these techniques. Surgical options remains as a gold standard when adequate symptom relief is not achieved through minimally invasive means.

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.

Reliability of focal identification of motor fascicles of the ulnar nerve proximal to the wrist: an anatomical study

We investigated whether motor fascicles of the ulnar nerve can be reliably identified proximal to the wrist. In 17 cadaveric upper limbs, the anterior interosseous nerve was transected at its arborization in the pronator quadratus and transposed to the palmar aspect of the ulnar nerve. The motor fascicular bundle was identified at this level after distinguishing the intraneural epineural involution by microsurgical probing. The motor branch was identified in Guyon's canal and traced retrograde via intraneural dissection to assess accuracy of the original identification. The motor fascicular bundle was found to have been correctly identified in all specimens. We conclude that local anatomic landmarks allow for the motor fascicular group to be correctly identified. Therefore, retrograde, internal dissection of the ulnar nerve is not likely to be required for reliable transfer of anterior interosseous nerve to ulnar nerve motor fascicles.

Endoscopic Release of the Guyon Canal and Pisohamate Hiatus

The ulnar nerve runs in more than 1 tunnel in the wrist. Ulnar nerve entrapment in the wrist can occur at the Guyon canal and the pisohamate hiatus. Open release of these 2 tunnels requires a lengthy incision and extensive soft-tissue dissection. The purpose of this technical note was to describe the details of endoscopic release of the Guyon canal and the pisohamate hiatus. This minimally invasive approach allows release of the ulnar nerve and its motor branch at the wrist level.

Ulnar neuropathy at wrist: entrapment at a very "congested" site

Ulnar tunnel syndrome indicates ulnar neuropathy at different sites within the wrist. Several classifications of ulnar tunnel syndrome are present in literature, based upon typical nerve anatomy. However, anatomical variations are not uncommon and can complicate assessment. The etiology is also complex, due to the numerous potential causes of entrapment. Clinical examination, neurophysiological testing, and imaging are all used to support the diagnosis. At present, many therapeutic approaches are available, ranging from observation to surgical management. Although ulnar neuropathy at the wrist has undergone extensive prior study, unresolved questions on diagnosis and treatment remain. In the current paper, we review relevant literature and present the current knowledge on ulnar tunnel syndrome.

Ulnar Neuropathy in Cyclists

The form and function of the cyclist exposes the ulnar nerve to both traction and compressive forces at both the elbow and wrist. Prevention of ulnar neuropathy and treatment of early symptoms include bike fitting, avoidance of excessive or prolonged weight-bearing through the hands, and the use of padded gloves. For persisting or progressive symptoms, a thorough history and physical examination is essential to confirm the diagnosis and to rule out other sites of nerve compression. The majority of compression neuropathies in cyclists resolve after appropriate rest and conservative treatment; however, should symptoms persist, nerve decompression may be indicated.

Analysis of the position of the branches of the ulnar nerve in Guyon's canal using high-resolution MRI in positions adopted by cyclists

PURPOSE

To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon's canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists.

MATERIALS AND METHODS

Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH.

RESULTS

The mean distances between the SB (d s) and DP (d p) and HH were 2.4 and 0.6 mm, respectively. The d s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it.

CONCLUSION

This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon's canal syndrome in cyclists.