Guyon’s Canal Syndrome Flashcards
1
Q
Introduction
A
- Guyon’s canal, also called ulnar tunnel or ulnar canal, is an anatomical fibro-osseous canal located on the medial side of the hand
- it extends between the proximal boarder of the pisiform bone and distally at the hook of the hamate
- the ulnar nerve and ulnar artery pass through the Guyon canal as they pass from distal forearm to the hand
- Guyon’s canal, also called ulnar tunnel or ulnar canal, is an anatomical fibro-osseous canal located on the medial side of the hand
- it extends between the proximal boarder of the pisiform bone and distally at the hook of the hamate
- the ulnar nerve and ulnar artery pass through the Guyon canal as they pass from distal forearm to the hand
2
Q
Description
A
- the Guyon canal houses the ulnar nerve and its branches, ulnar artery and venous and lymphatic vessels
- as the ulnar nerve exits the Guyon’s canal it is divided into deep (motor) branch of the ulnar nerve and superficial (sensory) branch of the ulnar nerve
3
Q
Borders
A
- roof: palmar carpal ligament,palmaris brevisand hypothenar connective tissue
- floor: transverse carpal ligament, pisohamate ligament, pisometacarpal ligament,flexor digitorum profundustendons andopponens digiti minimi
- medial wall:pisiform,abductor digiti minimiandflexor carpi ulnaristendon
- lateral wall: hook ofhamate, transverse carpal ligament and the flexor tendons
4
Q
Clinical Relevance
A
- Guyon canal syndrome is the 2nd reason for compression syndromes at the wrist after carpal tunnel syndrome
- compression of the ulnar nerve at the Guyon’s canal leads to specific sensory and motor symptoms according to the location of the compression
- hypothenar hand syndrome is caused by repeated trauma to the hypothenar region, resulting in injury to the ulnar artery
5
Q
Introduction
A
- aka Ulnar Tunnel Syndrome is a relatively rare peripheral ulnar neuropathy
- aka ulnar tunnel syndrome or handlebar palsy
- a compression of the distal ulnar nerve at the level of the wrist as it enters the hand through the ulnar tunnel or Guyon canal
- the clinical presentation can be purely sensory, purely motor or both depending on the location of the nerve compression
- ulnar nerve is one of the major nerves of the hand and travels down the neck through the medial epicondyle, than passes under the forearm muscles than to the little finger along side the palm
6
Q
Clinically Relevant Anatomy
A
- ulnar nerve emerges from the medial cord (C8-T1) of the brachial plexus, it travels into the axilla and passes in the anterior compartment of the arm, then it pierces the intramuscular septum and travels in the posterior compartment
- then travels posterior to the medial epicondyle into the cubital fossa
- hen passes between the flexor carpi ulnaris and flexor digitorum profundus
- gives off dorsal cutaneous branch proximal to the pisiform bone, before it enters Guyon’s canal
7
Q
Etiology
A
- injury to the distal ulnar nerve can be due to compression, trauma, inflammation or vascular insufficiency
- ganglion cysts
- tumors
- anatomical anomalies, can be hypertrophic muscle of normal anatomy or unusual location
- Ulnar artery thrombosis or aneurysm
- fractures or dislocations (hook of hamate fracture/displacement)
- repetitive trauma (hypothenar area by the handlebar in cyclists)
- Carpel tunnel syndrome can lead to anatomical changes in the ulnar tunnel leading to functional impairments
- iatrogenic
8
Q
Clinical Presentation
A
- as the ulnar nerve passes through Guyon’s canal it splits into deep motor branch and superficial sensory branch
- Guyon’s canal is divided into 3 zones, compression on the ulnar nerve at each zone results in specific symptoms
-Zone 1:
+ refers to compression at the proximal end of Guyon’s canal, proximal to the bifurcation of the ulnar nerve into sensory and motor branches
+ leads to mixed sensory and motor symptoms resulting in sensory deficits over the hypothenar, little finger and the medial half of the ring finger and motor weakness of all ulnar innervated intrinsic muscles
- Zone 2:
+ refers to compression only at the deep motor branch of the nerve, distal to the bifurcation
+ only motor symptoms would develop resulting in motor weakness in the hand muscles innervated by the ulnar nerve
+ may occur at pisohamate hiatus after the nerve to abductor digit minimi takeoff, which would result in weakness in the intrinsic muscles of the hand with possible sparing of the hypothenar muscles
- Zone 3:
+ compression at the superficial sensory branch, it manifests as sensory deficits on the palmer side of the ring finger and the palmer-medial side of the ring finger without hypothenar and interosseous weakness
+ compression on the ulnar nerve in zone 1 at the palmer aspect of the nerve can also result in pure sensory symptoms
9
Q
History
A
- Guyon’s canal syndrome is diagnosed clinically
- may be history of repetitive trauma or stress to the hypothenar area of the hand
- long distance cyclists can acquire Guyon’s canal syndrome as a result of the handle bar pressure on the wrist
- symptoms can be purely motor or purely sensory or both according to the site of compression
10
Q
Physical Examination
A
- first step in physical examination is observation of the hand for clawing, atrophy of the hypothenar or interossei, inability to cross fingers or any masses over the wrist
- tenderness over the hook of hamate can indicate fracture
- Tinel’s sign involves tapping over the location of suspected nerve compression would reproduce symptoms
- Froment’s sign is observed; weakness in adductor pollicis (supplied by the ulnar nerve) would result in compensatory movement of thumb flexion instead of thumb adduction
- examination of the arterial blood supply of the hand by Allen’s test is useful in cases of suspected ulnar artery thrombosis
11
Q
Management
A
- similar to that of carpel tunnel syndrome, it includes conservative management or surgical decompression
- conservative treatment is recommended for mild and moderate symptoms with duration of less than 3 months
- surgical treatment is recommended for moderate to very severe symptoms with duration of at least 2 months
12
Q
Physical Therapy Management
A
- conservative treatment consists of patient instructions and splinting
- ultrasound and nerve glide exercise can be added
- Ulnar nerve glide exercise: wrist extension, forearm pronation, elbow flexion, glenohumeral lateral rotation, glenohumeral depression, shoulder abduction
- avoid activities that cause repetitive stress at Guyon’s canal: weight bearing or cycling or modification of the bicycle handlebars
- avoid static postures or repetitive movements that places mechanical overload (prolonged wrist extension)
- patient is instructed to wear resting hand splint to place the wrist in neutral position
- splint should be worn for 1-12 weeks during nighttime and at daytime during aggravating activities
13
Q
Surgical Decompression
A
- aim of surgery is to decrease pressure on the ulnar canal in Guyon’s canal by removing the roof of the Guyon canal or removing the structures compressing the nerve
- during the early post-operative period (up to 10-15 days after surgery), patient is advised to elevate the hand, provide appropriate rest, do gradual hand and wrist movements without resistance as tolerated and avoid applying heavy loads on the hand or doing forceful activities
- post-surgical instructions include scar care, edema control, hand and wrist mobilization and ergonomics advice to avoid putting mechanical load on the nerve
- splinting after surgery is not routinely indicated, it is indicated for patients with severe pain after surgery and patients who are likely to put mechanical load on the canal
- post-surgical exercise is indicated
14
Q
Differential Diagnosis
A
- Alcohol-related neuropathy
- Amyotrophic lateral sclerosis
- Brachial plexus abnormalities
- Cervical disc disease
- Cervical spondylosis
- Epicondylitis
- Pancoast tumour
- Thoracic outlet syndrome
- Traumatic peripheral nerve lesions
