The ulnar nerve runs through Guyon’s canal at the wrist and will be compromised if there is a lesion occupying Guyon’s canal, such as a lipoma, ganglion, ulnar artery aneurysm or muscle abnormality. Repeated trauma, such as jackhammering or handlebar pressure in cyclists, can also cause ulnar neuropathy in the wrist.

Injury to the distal ulnar nerve can occur through

  • Compression
  • Inflammation
  • Trauma
  • Vascular insufficiency [5][6][7]

Two carpal bones are important in relation to the ulnar nerve at the wrist

  • Pisiforme
  • Hamatum

What are the causes of Guyon’s canal syndrome?

  • Palmar ganglion cyst
  • Fracture of the hamate hook
  • Hypertrophy of the palmar muscle
  • Fracture or dislocation of the pisiform
  • Tumors (lipoma)
  • Repetitive strain injuries (e.g. external compression of a cyclist’s handlebars)
  • Aberrant muscle (e.g. abductor digiti minimi) or excess fatty tissue in the canal
  • Ulnar artery thrombosis or aneurysm (e.g., hypothenar hammer syndrome)

What are the symptoms of Guyon’s canal syndrome?

Symptoms generally start with a numbing sensation in the ring and little fingers, usually early in the morning when the patient wakes up. They may progress to a shooting pain in the wrist and hand, which is followed by a reduction in sensation in the ring and little fingers.

Differential diagnosis

  • Carpal tunnel syndrome (paresthesia in thumb, index, long and ring fingers)
  • Cervical radiculopathy (C7-C8)
  • Peripheral neuropathy
  • Thoracic outlet syndrome
  • Ulnar compression at the elbow
  • Wrist arthritis
  • Alcohol-related neuropathy
  • Amyotrophic lateral sclerosis
  • Brachial plexus abnormalities
  • Cervical disc disease
  • Cervical spondylosis
  • Épicondylitis
  • Pancoastal tumor
  • Traumatic injuries of peripheral nerves

Therapeutic approach

  • Eliminate causes of nerve compression
  • Reduce or stop activities that aggravate symptoms

Référence

  1. Ramage JL, Varacallo M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 11, 2021. Anatomy, Shoulder and Upper Limb, Hand Guyon Canal. [PubMed]
  2. Strohl AB, Zelouf DS. Ulnar Tunnel Syndrome, Radial Tunnel Syndrome, Anterior Interosseous Nerve Syndrome, and Pronator Syndrome. Instr Course Lect. 2017 Feb 15;66:153-162. [PubMed]
  3. Jiménez I, Manguila F, Dury M. Hypothenar hammer syndrome. A case report. Rev Esp Cir Ortop Traumatol. 2017 Sep – Oct;61(5):354-358. [PubMed]
  4. Hu SY, Choi JG, Son BC. Type III Guyon Syndrome in ‘B Boy’ Break-Dancer: A Case Report. Korean J Neurotrauma. 2015 Oct;11(2):183-6. [PMC free article] [PubMed]
  5. Depukat P, Mizia E, Kuniewicz M, Bonczar T, Mazur M, Pełka P, Mróz I, Lipski M, Tomaszewski K. Syndrome of canal of Guyon – definition, diagnosis, treatment and complication. Folia Med Cracov. 2015;55(1):17-23. [PubMed]
  6. Brown CK, Stainsby B, Sovak G. Guyon Canal Syndrome: lack of management in a case of unresolved handlebar palsy. J Can Chiropr Assoc. 2014 Dec;58(4):413-20. [PMC free article] [PubMed]
  7. Hui-Chou HG, McClinton MA. Current options for treatment of hypothenar hammer syndrome. Hand Clin. 2015 Feb;31(1):53-62. [PubMed]
  8. Chen SH, Tsai TM. Ulnar tunnel syndrome. J Hand Surg Am. 2014 Mar;39(3):571-9. [PubMed]
  9. Andreisek G, Crook DW, Burg D, Marincek B, Weishaupt D. Peripheral neuropathies of the median, radial, and ulnar nerves: MR imaging features. Radiographics. 2006 Sep-Oct;26(5):1267-87. [PubMed]
  10. van Tulder M, Malmivaara A, Koes B. Repetitive strain injury. Lancet. 2007 May 26;369(9575):1815-1822. [PubMed]
  11. Kaiser R, Houšťava L, Brzezny R, Haninec P. [The results of ulnar nerve decompression in Guyon’s canal syndrome]. Acta Chir Orthop Traumatol Cech. 2012;79(3):243-8. [PubMed]

Credit in part: Dmitri Aleksenko; Matthew Varacallo.

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