Guyon Canal Syndrome


Article Author:
Dmitri Aleksenko


Article Editor:
Matthew Varacallo


Editors In Chief:
Evelyn Metz
Julie Sewell
Aditya Arya


Managing Editors:
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Frank Smeeks
Kristina Soman-Faulkner
Benjamin Eovaldi
Radia Jamil
Sobhan Daneshfar
Saad Nazir
William Gossman
Pritesh Sheth
Hassam Zulfiqar
Navid Mahabadi
Steve Bhimji
John Shell
Matthew Varacallo
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Hajira Basit
Phillip Hynes


Updated:
5/5/2019 10:11:13 PM

Introduction

Guyon's canal syndrome is a relatively rare peripheral ulnar neuropathy which involves injury to the distal portion of the ulnar nerve as it travels through a narrow anatomic corridor at the wrist. The ulnar nerve originates from C8-T1 and is a terminal branch of the brachial plexus.  In the upper arm, the ulnar nerve courses posterior and medial to the brachial artery, and heads for the posterior aspect of the elbow, piercing the medial intermuscular (IM) septum at the arcade of Struthers.  The nerve pierces the medial IM septum approximately 8 cm proximal to the medial epicondyle.[1][2][3][4]

The ulnar nerve enters the cubital tunnel posterior to the medial epicondyle, and enters the forearm by piercing between the two heads of the flexor carpi ulnaris (FCU) muscle.  The ulnar nerve reaches the hand via Guyon's canal to provide motor and sensory innervation to the digits. Guyon's canal is a unique location where ulnar nerve is vulnerable to compressive injury, although the more common location of the ulnar nerve injury occurs at the elbow which is known as cubital tunnel syndrome.

The anatomic boundaries of Guyon's canal include:

  • Volar carpal ligament - the "roof"
  • Transverse carpal ligament - the "floor"
    • Note that the transverse carpal ligament spans Guyon's canal as the floor at the ulnar side of the hand/wrist before seamlessly transitioning to its position as the "roof" of the carpal tunnel
  • Pisiform, Pisohamate ligament, abductor digiti minimi - ulnar boundary
  • Hook of hamate - radial boundary

Etiology

Injury to Distal Ulnar Nerve may occur through compression, inflammation, trauma or vascular insufficiency. [5][6][7]Etiologies include:

  • Ganglion Cyst
  • Hook of Hamate Fracture/Displacement
  • Tumors (e.g., lipoma)
  • Repetitive trauma (e.g., Cyclist's Handlebar external compression)
  • Aberrant Muscle (e.g., abductor digiti minimi) or excess fat tissue within the canal
  • Ulnar Artery Thrombosis or Aneurysm (e.g., Hypothenar Hammer Syndrome)

Hypothenar Hammer Syndrome (HHS) is a unique mechanism of ulnar nerve injury secondary to ulnar artery thrombosis or an aneurysm, which results in inflammation and subsequent compression of the ulnar nerve at Guyon's canal. Etiology of hypothenar hammer syndrome is similar to that of Guyon's canal syndrome where repetitive trauma to hypothenar area eventually results in injury to the ulnar artery. 

Some studies estimate that 30% to 40% of Guyon's canal syndromes result from ganglion cysts. Another study estimates 45% of cases to be idiopathic.

Epidemiology

The most commonly reported cases of Guyon's canal syndrome are due to a ganglion cyst and repetitive trauma. Unfortunately, the incidence and prevalence of Guyon's canal syndrome in the general population have not yet been accurately estimated due to lack of studies.

Pathophysiology

Guyon's canal is about 4 cm in length and housed by four borders. The roof consists of the volar carpal ligament. The floor is made of the transverse carpal ligament. The radial border has the Hook of Hamate, and the medial border is composed of pisiform bone along with pisohamate ligament. Inside this canal runs ulnar nerve and artery. The ulnar nerve enters the canal as a mixed sensory and motor nerve. As it travels through it, the nerve splits into superficial sensory and deep motor branches.

Each part of ulnar nerve which is affected within Guyon's canal region is represented by a particular zone and gives its unique constellation of symptoms.

Zone 1: proximal to the motor/sensory bifurcation

  • Area of the distal portion of the ulnar nerve (main trunk) before it splits into its superficial sensory and deep motor divisions
  • Etiologies include hook of hamate fracture/malunion/nonunion, ganglion cysts
  • Zone 1 Guyon's canal injury to the ulnar nerve results in mixed motor and sensory symptoms

Zone 2 (most commonly affected): distal to motor/sensory bifurcation, and radial to zone 3

  • Corresponds to the deep terminal motor branch of the ulnar nerve, if affected, it produces only motor symptoms (e.g. weakness)
  • Etiologies include hook of hamate fracture/malunion/nonunion, ganglion cysts
  • This deep branch of the ulnar nerve innervates all the interosseous muscles, fourth and fifth lumbricals, hypothenar muscles (opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis), and adductor pollicis muscle.

Zone 3: distal to motor/sensory bifurcation, and ulnar to zone 2

  • The superficial sensory terminal branch of the ulnar nerve is compromised in this zone producing sensory symptoms only (e.g., numbness and tingling, burning sensation)
  • Etiologies include unlar artery aneurysm and/or thrombosis

History and Physical

Guyon canal syndrome is usually diagnosed clinically. There may be a history of repetitive trauma (e.g., cyclists handlebar) or direct injury to the hand (e.g., fracture of Hamate). Signs and symptoms can be purely motor, purely sensory, or mixed depending on the zone of the distal ulnar nerve lesion as discussed above. Motor complaints may include weakness/paralysis of the intrinsic muscles of the hand innervated by the ulnar nerve, which may present as a weakening of the hand grip and clawing of the fourth and fifth digits. Hypothenar atrophy may be present in more advanced cases. Differentiation between ulnar nerve compression at Guyon's canal (wrist) vs. cubital tunnel (elbow) can be done by testing the strength of intrinsic (hand) vs. extrinsic (forearm) muscles supplied by the ulnar nerve respectively. Sparing of the dorsal surface of ulnar dermatome (dorsal medial hand and two fingers) points to Guyon's canal syndrome. This occurs because this region is innervated by the dorsal ulnar cutaneous branch which comes off about 5 cm proximal to the Guyon's canal entrance. Tinel's sign involves reproducing symptoms by tapping at the site of suspected nerve compression and can also be used for localization.[8][9][10][10]Compromise of the deep motor branch of ulnar nerve within Guyon's canal can result in weakness of the adductor pollicis muscle.  Clinically, this phenomenon can be assessed by asking the patient to simultaneously grip a sheet of paper at opposite ends.  The pathologic side may exhibit a Froment's sign, which by definition entails thumb IP joint hyperflexion (via FPL, innervated by AIN) to compensate for an inability to adduct the thumb.

When the fifth digit is observed in an over-abducted position at rest, this is known as Wartenberg's sign, which can be seen in ulnar nerve palsy as a consequence of denervation of the palmar interossei muscles that are normally responsible for digit adduction. Sensory involvement will produce pain and/or paresthesias of medial palm and ulnar half of the fourth digit and entire anterior side of the fifth digit.

Allen's Test evaluates arterial supply of the hand, which is useful when Ulnar Artery Thrombosis is suspected. 

The severity of symptoms can range from very mild to very severe on a spectrum of 1 to 5: very mild (1), mild (2), moderate (3), severe (4) and very severe (5).

Duration of symptoms can be acute (within one month), subacute (two to three months), or chronic (more than three months).

Evaluation

Hand x-ray or CT scan can be used to evaluate for fractures (especially hamate fracture).

MRI of the hand can show anatomical variations within Guyon's canal and evaluate for structures responsible for mechanical compression of the ulnar nerve (e.g., lipomas, ganglion cyst, aberrant muscle).

Doppler Ultrasound is used to evaluate for ulnar artery thrombosis.

Angiography can be used for evaluation of ulnar artery aneurysm or thrombosis.

EMG and nerve conduction velocity (NCV) are used to assess peripheral nerve compromise and localize the level at which nerve is affected (i.e., differentiate between ulnar nerve entrapment within Guyon's canal at the wrist vs. Cubital tunnel at the elbow vs. C8-T1 radiculopathy).

Treatment / Management

The decision to choose conservative vs. surgical management depends on the duration and severity of symptoms, as well as the exact etiology determined to be the cause of the symptoms.  For example, high-performance athletes and professional baseball players can develop hook of hamate fractures that can occur from acute trauma or repetitive pathologic contact during performance.  In this setting, the general consensus of hand surgeons is to perform an isolated hook of hamate incision, which has reliably demonstrated low/minimal rates of postoperative complications, return to play within 3 to 4 weeks, and high patient satisfaction scores. 

General considerations

Treatment of Guyon's canal syndrome is similar to that of carpal tunnel syndrome. Its spectrum consists of conservative management and surgical decompression. Conservative management involves patient instructions and splinting. Instructions are centered around avoidance of mechanical compression and repetitive stress at Guyon's canal. In the case of cyclists, utilization of more ergonomically favored handlebar positions can be used. Repetitive or prolonged wrist extension should be minimized as this exerts compressive forces on the ulnar nerve in the hand.

Wrist splinting must keep the wrist in neutral position but may allow fingers to move around freely. A splint is to be worn at least at night for a recommended duration of one to 12 weeks.

According to European Handguide study published in British Medical Journal, an expert panel of medical professionals had reached a consensus of utilizing conservative management for symptoms which are mild to moderate in severity and with acute to subacute duration lasting up to three months. For moderate to severe symptoms lasting three months or longer surgical decompression was favored. Surgical treatment may also include post-surgical exercises especially in those with reduced range of motion at the joint. Post-surgical splinting was not a necessity but can be used in those patients who have a habit of loading the wrist joint.

According to the same European Handguide study, NSAIDs and corticosteroid injections are not beneficial for the treatment of Guyon's canal syndrome.

Additional treatments that can be used include therapeutic ultrasound and nerve gliding exercises.

In the case of ulnar artery thrombosis or an aneurysm (hypothenar hammer syndrome), asymptomatic patients do not have to be treated surgically. However, when symptomatic, treatment will range from anti-platelet medication to surgical correction (e.g., bypass).

Pearls and Other Issues

Guyon's canal syndrome is a relatively uncommon ulnar neuropathy. Diagnosis can be challenging due to the variety of presenting signs and symptoms depending on the exact location of nerve compression in addition to the individual anatomic variations within Guyon canal itself. Although there are several articles suggesting approaches to diagnosis and management of Guyon's canal syndrome, due to a lack of large-scale empirical studies comprehensive guidelines have not yet been firmly established. For instance, it is unclear when a patient suspected of Guyon's canal syndrome should receive additional, more expensive testing such as MRI, or at which level of severity and duration of symptoms these additional tests are required. 

Enhancing Healthcare Team Outcomes

Guyon canal syndrome is a rare neurological disorder of the hand that is most common in young people. The disorder is difficult to diagnose and requires a multidisciplinary team that includes a hand surgeon, radiologist, neurologist, orthopedic surgeon and a therapist.

Treatment of Guyon canal syndrome is similar to that of carpal tunnel syndrome. Its spectrum consists of conservative management and surgical decompression. Conservative management involves patient instructions and splinting. Instructions are centered around avoidance of mechanical compression and repetitive stress at Guyon's canal. In the case of cyclists, utilization of more ergonomically favored handlebar positions can be used. Repetitive or prolonged wrist extension should be minimized as this exerts compressive forces on the ulnar nerve in the hand.

Patients who alter their lifestyle will note a significant improvement in the symptoms.[11][10]

 


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Guyon Canal Syndrome - Questions

Take a quiz of the questions on this article.

Take Quiz
A young cyclist presents with complaints of paresthesias in his ring and small finger of the left hand. He claims the symptoms started 8 weeks ago and have steadily become more severe. He denies any trauma. Exam reveals mild clawing of the ring and little finger and a weak grasp. Entrapment of a nerve between the pisiform and which other bone may produce this presentation?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient who rides a bike has been complaining of a "pins and needles" sensation in the ring and little fingers for the past 2 months. Lately, he has noticed decreased sensation and clumsiness of his hand. The individual is describing which of the following conditions?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A cyclist presents with complaints of weakness of his little and ring fingers of the right hand. He noticed that over the past 2 months, his grip on the handlebar has become weak. He denies any trauma. Examination reveals that he has mild clawing of the little and ring fingers with muscle atrophy. You suspect that he has compression of the nerve between the pisiform and the hook of the hamate. In the absence of sensory findings, he most likely has compression of the nerve in what Zone of the tunnel?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a feature of Guyon canal syndrome?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Guyon canal syndrome involves injury to which peripheral nerve?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
What special tests or signs can be useful in the diagnosis of Guyon canal syndrome?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 25-year-old male develops numbness along the palmar surface of the medial hand and two fingers along ulnar nerve distribution. The patient works in roofing and is involved in repetitive hammering. After his evaluation, Guyon canal syndrome is suspected. An injury to the ulnar nerve at what zone within Guyon canal would produce purely sensory symptoms?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 52-year-old right hand dominant female presents with complaints of numbness in her right hand. On physical exam, she exhibits decreased sensation in all fingers and weakness in the thenar, hypothenar, and intrinsic muscles of the hand. Her symptoms were being managed by her primary care provider, but she has seen no improvement and was referred to an orthopedic clinic. What is the best next course of action?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 29-year-old male complains of pain and numbness of his left hand for the past three months and has been progressively worsening since the onset of his symptoms. He is a professional baseball player and keeps up with a rigorous training schedule which includes aerobic exercise, strength training, and swinging practice for 7 to 9 hours a week. He claims he often "checks" his swing before and even during professional games. He has no significant past medical history and takes no performance-enhancing drugs. His vital signs are normal. Physical exam reveals weakness in grip strength and hypothenar atrophy in his left hand. There are also paresthesias in the fourth and fifth digits of the left hand. His right hand appears normal. Froment sign is positive in his left hand. Initial x-ray imaging is negative, and CT scan is pending. What is the best treatment for this patient's condition?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Guyon Canal Syndrome - References

References

Ramage JL,Varacallo M, Anatomy, Shoulder and Upper Limb, Hand Guyon Canal 2019 Jan;     [PubMed]
Strohl AB,Zelouf DS, Ulnar Tunnel Syndrome, Radial Tunnel Syndrome, Anterior Interosseous Nerve Syndrome, and Pronator Syndrome. Instructional course lectures. 2017 Feb 15;     [PubMed]
Jiménez I,Manguila F,Dury M, Hypothenar hammer syndrome. A case report. Revista espanola de cirugia ortopedica y traumatologia. 2017 Sep - Oct;     [PubMed]
Hu SY,Choi JG,Son BC, Type III Guyon Syndrome in 'B Boy' Break-Dancer: A Case Report. Korean journal of neurotrauma. 2015 Oct;     [PubMed]
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 medica Cracoviensia. 2015;     [PubMed]
Brown CK,Stainsby B,Sovak G, Guyon Canal Syndrome: lack of management in a case of unresolved handlebar palsy. The Journal of the Canadian Chiropractic Association. 2014 Dec;     [PubMed]
Hui-Chou HG,McClinton MA, Current options for treatment of hypothenar hammer syndrome. Hand clinics. 2015 Feb;     [PubMed]
Chen SH,Tsai TM, Ulnar tunnel syndrome. The Journal of hand surgery. 2014 Mar;     [PubMed]
Andreisek G,Crook DW,Burg D,Marincek B,Weishaupt D, Peripheral neuropathies of the median, radial, and ulnar nerves: MR imaging features. Radiographics : a review publication of the Radiological Society of North America, Inc. 2006 Sep-Oct;     [PubMed]
van Tulder M,Malmivaara A,Koes B, Repetitive strain injury. Lancet (London, England). 2007 May 26;     [PubMed]
Kaiser R,Houšťava L,Brzezny R,Haninec P, [The results of ulnar nerve decompression in Guyon's canal syndrome]. Acta chirurgiae orthopaedicae et traumatologiae Cechoslovaca. 2012;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of NP-Gerontology Primary Care. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for NP-Gerontology Primary Care, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in NP-Gerontology Primary Care, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of NP-Gerontology Primary Care. When it is time for the NP-Gerontology Primary Care board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study NP-Gerontology Primary Care.