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.

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.

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.