Ulnar two-point discrimination following endoscopic carpal tunnel release / La liberación endoscópica del túnel carpiano y la prueba de discriminación de dos puntos del nervio cubital

Abstract Carpal tunnel syndrome is median nerve symptomatic compression at the level of the wrist, characterized by increased pressure within the carpal tunnel and decreased nerve function at the level. Carpal tunnel release decreases pressure in Guyon's canal, via open techniques, with symptom and two-point discrimination improvement in the ulnar nerve distribution. We hypothesize that endoscopic carpal tunnel release improves two-point discrimination in the ulnar nerve distribution as well. This study includes 143 patients who underwent endoscopic carpal tunnel release between April 2016 to June 2019 in a single, community-based teaching hospital. A comprehensive retrospective chart review was performed on patient demographics, preand post-operative two-point discrimination test results, and complications. The effects of sex, age, and diabetes mellitus in the ulnar and median nerve territories with two-point discrimination tests were analyzed. As well as the differences in two-point discrimination among patient's based on their smoking status. There were significant post operative improvements in both the median (7.7 vs 4.4 mm, p < 0.001) and ulnar (5.7 vs 4.1 mm, p < 0.001) nerve territories. Smoking status, sex, age and diabetes did not significantly affect two-point discrimination outcomes. In conclusion the endoscopic release of the transverse carpal ligament decompresses the carpal tunnel and Guyon's canal, demonstrating improvement in two-point discrimination in both the ulnar and median nerve distributions.

Resumen El síndrome de túnel carpiano es la compresión sintomática del nervio mediano al nivel de la muñeca. Se caracteriza por un aumento de presión dentro del túnel y una disminución de la función del nervio a ese nivel. La liberación del túnel carpiano descomprime el canal de Guyon, con mejoría sintomática y en la prueba de discriminación de dos puntos en la distribución del nervio cubital. Hipotetizamos que la liberación endoscópica mejora de la misma manera en la distribución del nervio cubital. Este trabajo incluye 143 pacientes que tuvieron liberación endoscópica del túnel carpiano entre abril del 2016 y junio del 2019 en un hospital Universitario de la comunidad. Se evaluaron retrospectivamente las historias clínicas para los datos demográficos, los resultados pre y post quirúrgicos en la prueba de discriminación de dos puntos y complicaciones. Se analizaron los efectos del sexo, edad, tabaco y diabetes en los resultados de la prueba de discriminación de dos puntos para los nervios cubital y mediano. Hubo mejoría significativa post quirúrgica en la prueba de discriminación de dos puntos para los nervios mediano (7.7 vs 4.4 mm, p < 0.001) y cubital (5.7 vs 4.1 mm, p < 0.001). Fumadores, sexo, edad, y diabetes no afectaron de forma significativa. Concluimos que la liberación endoscópica del ligamento transverso del carpo descomprime el túnel carpiano y el canal de Guyon con mejoría en la prueba de discriminación de dos puntos para los nervios cubital y mediano.

Compression of Ulnar Nerve by Ganglionic Cyst in Guyon’s Canal: A Case Report.

Ulnar nerve compression at guyon’s canal is rare and very few cases have been reported in literature. It can be missed due to its rarity. Symptoms vary from pain and paresthesia to wasting and significant loss of muscle strength, with significant deformities of the hand. The diagnosis is made by detailed history and examination, electromyography, nerve conduction velocity test, ultrasound and magnetic resonance imaging. Early decompression of nerve is treatment of choice. Here we are presenting a case of compression of ulnar nerve in guyon’s canal due to ganglionic cyst.

Ulnar Nerve, Its Termination and Superficial Branches in Hand: A Cadaveric Study.

Introduction: Nerves supplying the hand are notoriously variable in their divisions and their course; do not follow any standard pattern. The palmar aspect of hand is supplied by median and ulnar nerve. The clinical importance of Guyon’s canal is emphasized due to the various branching patterns of the ulnar nerve in this canal. The palmar aspect of hand is usually supplied by ulnar nerve and median nerve. Medial one and a half fingers are supplied by ulnar nerve and lateral three and a half fingers are supplied by the median nerve. The branches of ulnar nerve are notoriously variable morphologically and no standard pattern can be given regarding the course of these branches. Presence of trifurcation of ulnar nerve or communications of superficial branches to median nerve do not cause symptoms usually but becomes important during surgical and orthopaedic interventions. Material and Methods: The study was conducted on 40 hands (20 left and 20 right ) of preserved adult human cadavers.The roof of the Guyon’s canal was opened with care not to disturb the stuctures. The ulnar nerve observed for its terminal branches, the course of its superficial branches was observed. The point of division of superficial branch into digital branches was measured from bistyloid line. The point of origin of superficial communicating branch from superficial branch or digital branch of ulnar nerve to median nerve was observed from bistyloid line. Observations: In 29 hands the ulnar nerve showed bifurcation, in 10 hands it trifurcated in the Guyon’s canal and in 1 right hand of a male cadaver there was higher division of the ulnar nerve and trifurcation.The superficial branch was observed for its course and division from bistyloid line. The superficial branch gave rise to 2 digital branches in 27 hands and it gave 3 branches i.e. 2 digital branches and 1 communicating branch to medialmost digital branch of median nerve in 13 hands. The typical ramus communicans from digital branch of ulnar nerve to the medial most digital branch of median nerve was observed in 27 hands.(67.5%). Conclusion: This study attempted at exploring the superficial anatomy of ulnar nerve in hand.The branching pattern of the ulnar nerve in Guyon’s canal is variable as there is no exact level at which the nerve terminates.The superficial communicating branch to median nerve though present in all the hands but the typical ramus communicans was observed in 67.5% of specimens. Thus surgical procedures in hand should be planned carefully keeping in mind in advance such variations which can be encountered.

Tortuous ulnar artery and Gantzer’s muscle: A rare presentation with clinical implications.

The ulnar artery, larger terminal branch of brachial artery is one of the principal arteries contributing to the vascular supply of forearm. It passes through a narrow tunnel, the Guyon’s canal, along with the ulnar nerve at the level of wrist. Ulnar artery is approached during surgical interventions like, coronary and cerebral angiography, ulnar-cephalic arteriovenous fistula etc., in situations where access to radial artery fails. The lesions of ulnar artery such as aneurysms, tortuosity, aberrancy, etc. may lead to entrapment neuropathies of the ulnar nerve. We have reported here a case of tortuous ulnar artery in the distal forearm and hand of the left side of a 62 years old male, which is a rare finding observed during routine educational cadaveric dissection. The tortuosity was observed in the form of twists and bends at various levels in 15cm long segment of ulnar artery in the distal forearm wrist and hand up to the commencement of superficial palmar arch. An aberrant head of flexor pollicis longus was seen crossing the ulnar artery. The ulnar artery of right side was normal and no other anatomical variations were seen. Such muscular variations may simulate soft tissue tumors resulting in nerve or vascular compressions and also influence the biomechanics of wrist and hand. An understanding of variations in the regional anatomy is essential for surgeons, cardiologists and neuroradiologists for preventing failure of surgical procedures.

Identification of Double Compression Lesion of Ulnar Nerve after Cubital Tunnel Release

The double compression syndrome of the ulnar nerve is a rare condition. Herin, we experienced double compression of ulnar nerve at cubital tunnel and Guyon's canal by re-evaluation after surgical decompression of cubital tunnel. We might suspect the double compression lesion in cases of worsening of symptom or nerve conduction velocity findings in a relative short duration of symptom as in our case. Meticulous physical examination might be needed to detect the Guyon's canal syndrome as a comorbidity in the treatment of cubital tunnel syndrome and re-evaluation for dual compression might be recommended if the resolution of symptom was not achieved after surgical decompression of single nerve lesion.

Ulnar Artery Thrombosis in Guyon's Canal

Causes of ulnar nerve compression in Guyon's canal are various, but thrombosis of the ulnar artery due to a single trauma is rarely reported. We report a case of ulnar nerve compression caused by traumatic thrombosis of the ulnar artery in Guyon's canal. Surgical excision of the ulnar artery thrombus and end to end anastomosis resulted in complete relief of the patient's symptoms.

Ulnar Neuropathy Caused by a Schwannoma in the Guyon's Cannal / 대한정형외과학회잡지

Guyon's canal syndrome is a compression neuropathy of the ulnar nerve entrapment at the wrist. Compression of the ulnar nerve at the wrist by a ganglion, lipomas, diseases of the ulnar artery, fractures of the hamate and trauma is a common etiological factor. We report on a rare case of ulnar neuropathy caused by a schwannoma at the level of Guyon's canal.

An Anatomic Variation of the Accessory Abductor Digiti Minimi Muscle / 체질인류학회지

Accessory muscles passing through Guyon's canal are common; the most common anomalous muscle at Guyon's canal is the accessory abductor digiti minimi muscle (AADM). The aim of this study was to demonstrate and describe the gross anatomy of an anatomic variant of the AADM relative to the surrounding structures. The AADM was found in the left forearm and hand of a 61-year-old male cadaver during dissection in a gross anatomy course. It was observed by focusing on the shape, the course, and its relationship with the surrounding structures. The AADM originated as muscle fibers from the antebrachial fascia. It coursed downward in the distal forearm and crossed the ulnar nerve and artery obliquely at Guyon's canal. The AADM narrowed and became a long tendon in the hypothenar region. The abductor digiti minimi muscle was partly attached to the tendon of the AADM, running along the tendon. The tendon of the AADM inserted into the ulnar side of head of the fifth metacarpal bone. The AADM was innervated by several twigs from the ulnar nerve. We reported herein another variant of the AADM at Guyon's canal, which may be helpful to surgeons performing diagnoses and surgical procedures.

Ulnar Nerve Compression in Guyon's Canal by Ganglion Cyst

Compression of the ulnar nerve in Guyon's canal can result from repeated blunt trauma, fracture of the hamate's hook, and arterial thrombosis or aneurysm. In addition, conditions such as ganglia, rheumatoid arthritis and ulnar artery disease can rapidly compress the ulnar nerve in Guyon's canal. A ganglion cyst can acutely protrude or grow, which also might compress the ulnar nerve. So, clinicians should consider a ganglion cyst in Guyon's canal as a possible underlying cause of ulnar nerve compression in patients with a sudden decrease in hand strength. We believe that early decompression with removal of the ganglion is very important to promote complete recovery.

Ulnar Artery Obstruction in Guyon Canal Compression Syndrome

PURPOSE: There are many articles describing about Guyon canal compression syndrome. Until recently, most of these articles have been presented about the symptoms of ulnar nerve compression, but there have been no reports about ulnar artery compression. In this article, besides the nerve compression symptoms in the Guyon's canal, we represented the symptoms and treatments based on the ulnar artery obstruction. METHODS: Guyon canal is composed of the hamate and pisiform, and the ligaments which connect them. The course of the ulnar nerve and artery, which passes through this narrow canal, is affected by the anatomical structure of the base of the canal. Out of 14 patients (21 cases) were retrospectively reviewed in this study from 2006 to 2009. Of 14 patients, there were 5 men and 9 women with ages between 21 to 61 years old. The symptoms had volar sensory loss of ulnar sided digits, with muscular atrophy of hypothenar muscles. Prior to surgery, most of these patients had vascular disorders which was diagnosed definitively by angiography and electromyogram. RESULTS: The release of Guyon canal and interposition graft of the obstructed arteries was carried out to 11 patients (15 cases) who had artery (vascular) occlusive disorder, and. 12 cases had sympathectomy and interposition graft after resection of obstructed ulnar artery. Six cases had release of carpal tunnel performed simultaneously. There were no major complications after surgery. The circulation of the ulnar artery was improved along with the patients' symptoms. CONCLUSION: The pre-existing articles about Guyon canal compression syndrome were mainly focused on ulnar nerve compression. This study, which was carried out by our department, showed that most of these patients had ulnar artery obstruction or stenosis simultaneously with ulnar nerve compression. The vascular disorder was corrected by interposition graft after the resection of the site of ulnar artery occlusion. And to conclude, When we resolve the ulnar nerve compression, the proper diagnosis & treatment of impaired ulnar artery circulation should be carried out concomitantly.

Supernumerary Fascicle of Abductor digiti minimi Muscle and Compression of Ulnar Nerve and Ulnar Artery: A Case Report / Fascículo Supernumerario del Músculo Abductor del dedo Mínimo y Compresión del Nervio y Arteria Ulnares: Reporte de Caso

The supernumerary fascicles of abductor digiti minimi muscle have been implicated in vascular and nerve compression. During routine dissection of an old male cadaver we observed an anomalous muscle was found to take it's origin from the antebrachial fascia and flexor retinaculum, traversed ulnar canal (Guyon's) superficial to ulnar vessels and nerves to reach the proximal part of abductor digiti minimi. The anomaly is one of a kind. Its course through Guyon's canal could be a cause for Guyon's canal syndrome. It was innervated by the ulnar nerve.

Los fascículos supernumerarios del músculo abductor del dedo mínimo han sido implicados en la compresión neurovascular. Durante una disección de rutina de un cadáver masculino adulto, se observó un músculo anómalo que se originaba en la fascia antebraquial y en el retináculo flexor, atravesaba el canal ulnar, superficial a los vasos y nervio ulnares para llegar a la parte proximal del músculo abductor del dedo mínimo. La anomalía es única en su tipo. Su curso a través del canal ulnar puede causar el síndrome del canal ulnar. El músculo estaba inervado por el nervio ulnar.

The Safety of Entrance Reference Line in Endoscopic Carpal Tunnel Release: A Cadaveric Anatomical Evaluation

OBJECTIVE: The purpose of this study is to investigate the anatomic relationship between the neurovasular structures and transverse carpal ligment(TCL) to avoid complications during endoscopic carpal tunnel release. METHODS: Sixteen fresh cadaver hands from 3 men and 5 women(age range, 58~74 years) were used. Neurovascular structures around the TCL were meticulously dissected under a loupe magnification and several morphometric indices were calculated. RESULTS: We found an average length of TCL is 41mm and average distance between the TCL distal margin and superficial palmar arch along the flexor tendon of the ring finger is 9.2mm. In 3 hands, the looped ulnar artery, coursed 1 to 4mm radial to hook of hamate, continuing to the superficial palmar arch. During radial-to-ulnar flexion of the wrist, the looped ulnar artery beyond the hook of hamate shifts more radially (2 to 7mm) with proximal carpal bone. We also noted a Berretini branch located adjacent to the edge of the distal TCL. CONCLUSION: It is appropriate to transect the ligament at least 4mm radial from the radial margin of the hook of hamate or transect the proximal ligament in the radially deviated hand position to protect ulnar neurovascular structure. The proximal portal could be made just ulnar to the palmaris longus tendon to avoid the vascular injury in the proximal portion of the TCL.

ANATOMICAL STUDY ON THE FASCIAL ARCH OF THE OPPONENS DIGITI MINIMI / 解剖学报

Objective To explore the entrapment to the deep branch of the ulnar nerve at the wrist,to assist the surgeon in diagnosis and treatment of Guyon canal syndrome.Methods Twenty fresh upper limbs were dissected on loupe(?5),to record the relationship between the ulnar nerve and the hypothenar muscles,the course of the ulnar nerve at the wrist.Results The deep branchs of the ulnar nerve go through an intermuscular space after runing out of the Guyon canal.The intermuscular space consisits of the superficial and deep head of the opponens digiti minimi and the hook of the hamate,which has one entrance and one exit.We named the intermuscular space as the hiatus of opponens digiti minimi,and named the proximal edge of the superficial head of the opponens digiti minimi as the fascial arch of the opponens digiti minimi.Conclusion We found that the fascial arch of the opponens digiti minimi can compress the deep branch of the ulnar nerve causing motor deficit of the intrinsic muscles of hands.

Subclinical Ulnar Neuropathy in Carpal Tunnel Syndrome

BACKGROUND: When performing routine diagnostic nerve conduction studies in patients with carpal tunnel syndrome(CTS), we sometimes happen to be confronted with patients who have also ulnar nerve abnormality without any clinical symptoms or signs, although not so common. Anatomically, the borders of the carpal tunnel and the Guyon canal share common features, separated from each other by the pisiform bone, and the volar carpal ligament forming both the roof of the carpal tunnel and the floor of the Guyon canal. Therefore, if there is an entrapment syndrome at the carpal tunnel with subsequent electrophysiological changes for the median nerve, the same process could also affect the ulnar nerve in the Guyon canal. METHODS: We analyzed 283 patients who were diagnosed as CTS clinically and electrophysiologically for the past 5 years in this hospital. RESULTS: Of 283 patients(491 hands) with CTS, 15 patients(16 hands) had ulnar nerve involvement(5%). Of 75 patients with unilateral CTS, 2 patients(2%) had ulnar nerve involvement; whereas of 208 patients with bilateral CTS, 13 patients(6%) had ulnar nerve involvement. CONCLUSIONS: This study cannot conclusively explain why there is involvement of the ulnar nerve in CTS, but ulnar nerve may be involved at the level of the Guyon canal in some patients with CTS as an entrapment phenomenon and the patients with bilateral CTS may have a more tendency to have ulnar nerve lesion than those with unilateral CTS. In patients with CTS, it would be better to check up if there is also ulnar nerve involvement.