Anatomical and histomorphometric study of the ulnar nerve at the wrist / Estudio anatómico e histomorfométrico del nervio ulnar en la muñeca

SUMMARY: The ulnar nerve (UN) is the main nerve responsible for innervation of the intrinsic musculature of the hand. It is of great importance to have a deep anatomical knowledge of the UN. The aim of this study is to enrich the knowledge of the UN anatomy at the wrist and provide useful reference information for clinical and surgical applications. In this descriptive cross-sectional study, 44 upper limbs of fresh cadavers were evaluated. The UN, the superficial branch of the ulnar nerve (SBUN), and the deep branch of the ulnar nerve (DBUN) were evaluated. Morphometric variables were measured using a digital caliper, and samples of nervous tissue were taken to evaluate the histomorphometry. Before entering the Guyon's canal, the UN had a diameter of 3.2 ± 0.4 mm. In 36 samples (82 %) the UN presented a bifurcation pattern and in the remaining 8 samples (18 %) a trifurcation was shown. The diameter of the DBUN was 1.9 ± 0.33 mm and that of the SBUN was 1.29 ± 0.22 mm. In the bifurcation patterns, the SBUN had a trunk of 5.71 ± 1.53 mm before bifurcating into the common digital nerve (fourth and fifth fingers) and an ulnar digital collateral nerve (fifth finger). The DBUN had an area of 2.84 ± 0.7 mm2 and was made up of 8 ± 1.4 fascicles and 3595 ± 465 axons. The SBUN area was 1.31 ± 0.27 mm2, it was made up of 6 ± 1.1 fascicles and 2856 ± 362 axons. The reported findings allow the hand surgeon to improve his understanding of the clinical signs of patients with UN pathologies at the wrist level and thus achieve greater precision while planning and performing surgical approaches and dissections.

El nervio ulnar (NU) es el principal nervio responsable de la inervación de la musculatura intrínseca de la mano. Es de gran importancia tener un profundo conocimiento anatómico del NU. El objetivo de este estudio fue enriquecer el conocimiento de la anatomía del NU en la muñeca y proporcionar información de referencia útil para aplicaciones clínicas y quirúrgicas. En este estudio descriptivo transversal se evaluaron 44 miembros superiores de cadáveres frescos. Se evaluó el NU, el ramo superficial del nervio ulnar (RSNU) y el ramo profundo del nervio ulnar (RPNU). Las variables morfométricas se midieron con un caliper digital y se tomaron muestras del nervio para evaluar la histomorfometría. Antes de ingresar al canal del nervio ulnar (canal Guyon), el ONU tenía un diámetro de 3,2 ± 0,4 mm. En 36 muestras (82 %) el ONU presentó un patrón de bifurcación y en las 8 muestras restantes (18 %) se presentó una trifurcación. El diámetro del RPNU fue de 1,9 ± 0,33 mm y el del RSNU de 1,29 ± 0,22 mm. En los patrones de bifurcación, el RSNU presentó un tronco de 5,71 ± 1,53 mm antes de bifurcarse en el nervio digital común (cuarto y quinto dedo) y un nervio digital colateral ulnar (quinto dedo). El RPNU tenía un área de 2,84 ± 0,7 mm2 y estaba formado por 8 ± 1,4 fascículos y 3595 ± 465 axones. El área del RSNU fue de 1,31 ± 0,27 mm2, estaba formado por 6 ± 1,1 fascículos y 2856 ± 362 axones. Los hallazgos reportados permiten al cirujano de mano mejorar su comprensión de los signos clínicos de los pacientes con patologías del NU a nivel de la muñeca y así lograr una mayor precisión en la planificación y realización de abordajes y disecciones quirúrgicas.

Estratégia de tratamento nos tumores benignos de nervo / Treatment strategy for benign nerve tumors

Introdução: Os tumores de nervo periférico normalmente são benignos, raros, de crescimento lento e pouco sintomáticos. O objetivo é descrever estratégias para o diagnóstico e tratamento de pacientes com tumores benignos que afetam o nervo ulnar. Métodos: Estudo retrospectivo dos pacientes operados entre 2010 e 2015 com tumor benigno de nervo ulnar, segundo os sintomas, exames complementares, técnicas cirúrgicas realizadas e características demográficas. Resultados: O estudo incluiu 17(8%) pacientes, prevalência sexo feminino (65%) na quarta década de vida; e, natureza extrínseca, o lipoma, em seis casos (35%), seguido do tumor de origem intrínseca, o Schwannoma em 17% e hamartoma em 11%. A excisão tumoral foi total em 83% casos e parcial em 17% casos; em doze casos realizou-se a descompressão neural. Conclusão: Com as estratégias realizadas para o tratamento foi possível bons resultados funcionais em 88% dos pacientes operados. Os piores resultados foram nos tumores de origem vascular.

Introduction: Peripheral nerve tumors are usually benign, rare, slow-growing and little symptomatic. The objective is to describe strategies for the diagnosis and treatment of patients with benign tumors of the ulnar nerve. Methods: This retrospective study of patients who underwent surgery between 2010 and 2015 for the treatment of benign tumor of the ulnar nerve analyzed patient symptoms and demographic characteristics, complementary examinations, and surgical techniques performed. Results: The study included 17 (8%) patients, with a prevalence of women (65%) in the fourth decade of life. The tumors tended to be extrinsic, with lipoma in 6 cases (35%); others were intrinsic, including schwannoma in 17% and hamartoma in 11% of the cases. Tumor excision was complete in 83% of cases and partial in 17% of cases; nerve decompression was performed in 12 cases. Conclusion: The strategies performed here yielded good functional results in 88% of patients. The worst results were in tumors of vascular origin.

Diagnosis of Pure Ulnar Sensory Neuropathy Around the Hypothenar Area Using Orthodromic Inching Sensory Nerve Conduction Study: A Case Report

Ulnar neuropathy at the wrist is an uncommon disease and pure ulnar sensory neuropathy at the wrist is even rarer. It is difficult to diagnose pure ulnar sensory neuropathy at the wrist by conventional methods. We report a case of pure ulnar sensory neuropathy at the hypothenar area. The lesion was localized between 3 cm and 5 cm distal to pisiform using orthodromic inching test of ulnar sensory nerve to stimulate at three points around the hypothenar area. Ultrasonographic examination confirmed compression of superficial sensory branch of the ulnar nerve. Further, surgical exploration reconfirmed compression of the ulnar nerve. This case report demonstrates the utility of orthodromic ulnar sensory inching test.

Frecuencia de algunos signos de provocación para el nervio cubital en el codo en una población sana / Fréquence de quelques signes de provocation du nerf ulnaire au coude dans une population saine / Frequency of some signs of challenge to the ulnar nerve at the elbow in a healthy population

Introducción: el síndrome del túnel cubital en el codo es a menudo subdiagnosticado y confundido con la epicondilitis medial. Presenta, con frecuencia, variabilidad en las pruebas del codo contra gravedad; se determinó la proporción de signos positivos sobre el total de codos examinados. Objetivo: determinar en una población sana asintomática la frecuencia de los signos del síndrome del túnel cubital en el codo. Métodos: en 380 codos de una población voluntaria, se realizaron las pruebas de Tinel, de flexión del codo, de rotación interna y flexión del codo, el scratch-collapse y test de flexión del codo contra gravedad; se determinó la proporción de signos positivos sobre el total de codos examinados. Resultados: en total, 66 personas (34,7 por ciento) tuvieron al menos un test positivo en uno o ambos codos. El 45,4 por ciento de las mujeres y el 20,7 por ciento de los hombres tuvieron al menos un test positivo (p=0,001). La prueba de flexión del codo con estimulo de presión tuvo la mayor frecuencia (13,4 por ciento), luego la prueba de Tinel (8,9 por ciento). El test de flexión del codo contra gravedad (4,2 por ciento) y la prueba scratch-collapse (3,4 por ciento) obtuvieron bajas frecuencias. Conclusiones: el 34,7 por ciento de individuos tuvieron al menos un test positivo en uno o ambos codos, cifra alta que sugeriría una alta tasa de falsos positivos en pacientes con síndrome del túnel cubital. En las mujeres, que tenían el doble que los hombres de positividad, sugiere que algunos factores anatómicos, hormonales y otros desconocidos podrían influenciar en esto. El test de flexión del codo contra gravedad tiene en cuenta el flujo contra gravedad de la circulación arterial del nervio cubital, que sumado a la flexión del codo, reproduciría más rápido los síntomas en un paciente con síndrome del túnel cubital. En población sana se encontró una frecuencia baja (4,2 por ciento), lo cual se sugiere como un nuevo signo para apoyar el diagnóstico clínico. No obstante se requiere de otros estudios en pacientes con esta afección para determinar la sensibilidad y especificidad(AU)

Introduction: cubital tunnel syndrome in the elbow is often sub-diagnosed and confused with medial epicondylitis. Variability has often provocative tests. Objective: determine frequency of signs of cubital tunnel syndrome in the elbow in a healthy asymptomatic population. Methods: 380 elbows in a voluntary population were tested by Tinel tests, elbow flexion, internal rotation and elbow flexion, the scratch test-collapse and elbow flexion against gravity; the proportion of positive signs on total elbows examined was determined. Results: in total, 66 persons (34.7 percent) had at least one positive test on one or both elbows. 45.4 percent women and 20.7 men had at least one positivest (p = 0.001). The elbow flexion test with pressure stimulus had the highest rate (13.4 percent e test (p = 0.001). The elbow flexion test with pressure stimulus had the highest rate (13.4 percent), then Tinel test (8.9 percent). The test of elbow flexion against gravity (4.2 percent) and the scratch-collapse (3.4 percent) had low test frequencies. Conclusions: 34.7 percent of subjects had at least one positive test on one or both elbows. This high number would suggest high rate of false positives in patients with cubital tunnel syndrome. In women, they were positive twice as men, suggesting that some anatomical, hormonal and other unknown factors could influence. The test of elbow flexion against gravity takes into account the gravity flow against the arterial circulation of the ulnar nerve, which added to the elbow flexion reproduce faster symptoms in a patient with cubital tunnel syndrome. In the healthy population low frequency (4.2 percent) was found, which is suggested as a new sign to support the clinical diagnosis. However it requires further studies in patients with this condition to determine sensitivity and specificity(AU)

Introduction: le syndrome du tunnel cubital au coude est souvent mal diagnostiqué et confondu avec l'épicondylite médiale. D'habitude, les tests de provocation ont des résultats variables. Objectif: le but de ce travail est de déterminer la fréquence des signes du syndrome du tunnel cubital au coude dans une population saine asymptomatique. Méthodes: dans une population volontaire (380 coudes), on a effectué des tests cliniques tels que le test de Tinel, le test de flexion du coude, le test de rotation interne et flexion du coude, le test de scratch-collapse, et le test de flexion active du coude contre la gravité. On a déterminé la proportion de signes positifs sur le total de coudes examinés. Résultats: au total, soixante-six personnes (34.7 pourcent) ont eu au moins un test positif d'un ou de tous les deux bras. Il y a eu au moins un test positif (p=0.001) dans 45.4 pourcent des femmes et dans 20.7 pourcent des hommes. Le test de flexion du coude à stimulus de pression a été le plus fréquent (13.4 pourcent), suivi par le test de Tinel (8.9 pourcent). Le test de flexion du coude contre la gravité (4.2 pourcent) et le test de scratch-collapse (3.4 pourcent) n'ont pas été assez fréquents. Conclusions: dans 34.7 pourcent des cas, il y a eu au moins un test positif d'un ou de tous les deux coudes. Cette chiffre considérée haute suggère un haut taux de faux positifs chez les patients atteints de syndrome du tunnel cubital. Chez les femmes ayant une positivité deux fois plus haute que chez les hommes, elle suggère que des facteurs anatomiques, hormonaux et d'autres encore inconnus peuvent influer. Le test de flexion du coude contre la gravité tient en compte le flux contra la gravité de la circulation artérielle du nerf cubital qui, conjointement avec la flexion du coude, reproduit plus rapidement les symptômes du syndrome du tunnel cubital chez un patient. Dans une population saine, on a trouvé une basse fréquence (4.2 pourcent), ce qui indique un nouveau signe soutenant le diagnostic clinique. Toutefois, il faut faire de nouvelles études pour déterminer la sensibilité et la spécificité(AU)

Type III Guyon Syndrome in 'B Boy' Break-Dancer: A Case Report / 대한신경손상학회지

Although the musculoskeletal injuries associated with break-dancing which is gaining more popularity among adolescent and young people has been reported, the report regarding a peripheral nerve injury associated with breakdance is scarce. We report a rare case of a young amateur break-dancer, 'b-boy' who suffered from a painful paresthesia in his left hand, later diagnosed as type III Guyon's canal syndrome. A 23-year-old, right handed college man presented with a tenderness over the left hypothenar eminence and painful paresthesia over the ring and little fingers of 3 months duration. He trained himself as an amateur 'b boy' break-dancer for the last 10 months. Conservative management under the diagnosis of wrist sprain before presentation did not improve his hand pain. An magnetic resonance imaging and electrodiagnostic study revealed that painful paresthesia was caused by type III Guyon's canal syndrome, and 4 weeks of corticosteroid treatment was given with resolution of pain and paresthesia.

Misdiagnosed Handlebar Palsy: Giant Cell Tumor of the Tendon Sheath in Guyon's Canal / 대한스포츠의학회지

Ulnar tunnel syndrome (UTS) is a compressive neuropathy of the upper extremity that shows various clinical symptoms according to the anatomic region of the compression site. Numerous factors may cause UTS, and most publications are case reports describing various etiologies; thus, obtaining a correct diagnosis is often challenging. Giant cell tumor of the tendon sheath (GCTTS) is well described to be a common benign soft tissue tumor of the hand; however, it is rarely reported to cause UTS. We report a case of GCTTS in Guyon's canal causing UTS that was misdiagnosed as handlebar palsy.

Symptomatic Neural Loop of the Distal Ulnar Nerve / 대한정형외과학회잡지

We found a unique anatomical variant of the distal ulnar nerve, a neural loop encompassing the flexor carpi ulnaris during Guyon's canal exploration. Compression by the flexor carpi ulnaris during active wrist movement was suspected as the cause of ulnar neuropathy. The symptom was relieved after neurolysis and release of surrounding tissue. With regard to the ulnar side wrist pain, which is suspicious for ulnar compression syndrome at the wrist level, the surgeon should always suspect anomalous nerve branch as source of compressive neuropathic pain.

Accessory muscle in the forearm: a clinical and embryological approach / 대한해부학회지

Muscular variations of the flexor compartment of forearm are usual and can result in multiple clinical conditions limiting the functions of forearm and hand. The variations of the muscles, especially accessory muscles may simulate soft tissue tumors and can result in nerve compressions. During a routine dissection of the anterior region of the forearm and hand, an unusual muscle was observed on the left side of a 65-year-old male cadaver. The anomalous muscle belly arose from the medial epicondyle approxiamately 1 cm posterolateral to origin of normal flexor carpi ulnaris muscle (FCU), and from proximal part of the flexor digitorum superficialis muscle. It inserted to the triquetral, hamate bones and flexor retinaculum. Passive traction on the tendon of accessory muscle resulted in flexion of radiocarpal junction. The FCU which had one head, inserted to the pisiform bone hook of hamate and palmar aponeurosis. Its contiguous muscles displayed normal morphology. Knowledge of the existence of muscle anomalies as well as the location of compression is useful in determining the pathology and appropriate treatment for compressive neuropathies. In this study, a rare accessory muscle has been described.

Síndrome do canal de Guyon causada por cisto sinovial / Guyon's canal syndrome due to a synovial cyst

Apresentamos um caso de síndrome do canal de Guyon por um cisto sinovial no punho esquerdo de uma paciente do sexo feminino, de 48 anos. A paciente apresentava dor e parestesia na topografia do nervo ulnar, diminuição da força muscular e deformidade na mão esquerda. A eletroneuromiografia evidenciava compressão do nervo ulnar no nível do punho. Realizada a ressecção do cisto e descompressão do nervo no canal de Guyon. Após a cirurgia a paciente apresentou melhora da dor e da parestesia, além de aumento do trofismo muscular e correção da deformidade.

The authors present a case of Guyon's canal syndrome due to a synovial cyst within the left wrist of a 48-year-old female patient. The patient reported pain and paresthesia in the topography of the ulnar nerve, loss of muscular strength and left hand deformity. Electromyography showed a compression of the ulnar nerve at the wrist level. Surgical decompression at the Guyon canal with resection of the cyst was performed. After surgery, the patient presented with improvement of pain and paresthesia, as well as an increase in muscular trophism and correction of the deformity.

Compression of the Ulnar Nerve in the Ulnar Tunnel Caused by an Anomalous Pulsatile S-shaped Ulnar Artery

PURPOSE: Compression of the ulnar nerve in the ulnar tunnel is a relatively uncommon condition. Many authors have described several etiologies of ulnar nerve compression. We experienced two cases of ulnar nerve compression in the ulnar tunnel due to an anomalous pulsatile S-shaped ulnar artery. METHODS: Case 1: A 51-year-old man was referred with numbness and paroxysmal tingling sensation along the volar side of the ring and little fingers of his right hand for 6 months. When exploration, the ulnar artery was pulsatile S-shaped and was impinging on the ulnar nerve. To decompress the ulnar nerve, the tortuous ulnar artery was mobilized and translocated radially onto the adjacent fibrous tissue. Case 2: A 41-year-old man was referred with tingling sensation on the 4th, 5th finger of the right hand for 4 months. Sensory nerve conduction velocities of the ulnar nerve was delayed. Preoperative 3D angio CT scan showed an anomalous S-shaped ulnar artery. Same operation was done. RESULTS: The postoperative course was uneventful. After decompression, paroxysmal tingling sensation decreased to less than 1 minute per episode, occurring 1 or 2 times a day. After 4 months, they had no more episodes of numbness and tingling sensation. Examination demonstrated good sensation to pinprick and touch on the ulnar aspect of the hand. CONCLUSION: We report two cases of ulnar nerve compressive neuropathy that was caused by an anomalous pulsatile S-shaped ulnar artery in the ulnar tunnel. Although this is an unusual cause of ulnar nerve compression, the symptoms will not spontaneously resolve. The prompt relief of compressive neuropathic symptoms following the translocation of the impinging ulnar artery from the affected ulnar nerve onto adjacent tissue proved that the ulnar nerve compression is due to the anomalous vessel.

Localization of Ulnar Neuropathy at the Elbow by Short Segment Stimulation

BACKGROUND AND OBJECTIVES: Local compression of the ulnar nerve occurs most commonly at the elbow and optimal surgical intervention should be directed at the specific site of involvement. This study is designed to localize the more discrete region by using the method of short segment stimulation in ulnar neuropathy at the elbow. METHODS: Thirty seven patients who were diagnosed as entrapment ulnar neuropathy at the elbow by routine nerve conduction studies were investigated. Latency changes and amplitude changes including conduction block were determined by stimulating the ulnar nerve at 2cm intervals across the elbow. Six of these patients had orthopedic surgery after undergoing short segment stimulation studies. RESULT: All patients had significant latency changes(> OR =0.7msec) in specific segments by short segment stimulation and 6 patients of them showed conduction block. The most frequently involved segments were between medial epicondyle and 2cm proximal(20 patients) and between medial epicondyle and 2cm distal(9 patients). Only two patients exhibited significant latency changes between 2 and 4cm distal to the medial epicondyle, suggesting cubital tunnel syndrome. Lesions, as identified by surgery, proved to be accurately predicted by preoperative short segment stimulation in 5 of 6 patients. CONCLUSION: Short segment stimulation studies are helpful in localizing more accurate involved segment in ulnar neuropathy at the elbow. And the most commonly involved site is within 2cm of the medial epicondyle suggesting tardy ulnar nerve palsy.