Forearm/Wrist

Question 1

Volar Henry Approach

Answer 1

Anterior approach to radius

• Incision: lateral to biceps tendon at flexor crease to radial styloid
• Interval: brachioradialis (radial n) and pronator teres (median) proximally / FCR (median) distally
• Deep dissection proximal 1/3: lateral to biceps tendon at bicipital tuberosity (artery is medial here) with arm supinated to protect PIN (subperiosteally elevate supinator from insertion medial to lateral)
• Middle 1/3: pronate arm and subperiosteally elevate PT from lateral to medial (also detaches FDS origin)
• Distal 1/3: subperiosteally elevate PQ lateral to medial (and also retract FPL medially)
• Dangers: superficial radial nerve (underside of brachioradialis), radial artery (under brachioradialis proximally, radial to FCR distally) and branches (recurrent radial artery just below elbow), PIN (within supinator proximally)

Question 2

Volar Henry to Wrist

Answer 2

FCR

• Incision: over FCR tendon, curve at wrist crease to avoid crossing perpendicularly (can curve either direction)
• Interval: FCR, radial artery
• Superficial dissection: ID FCR and go through floor of tendon sheath (take tendon ulnarly)
• Deep dissection: ID FPL and retract ulnarly, elevate PQ radially to ulnarly to expose radius
• Dangers: palmar cutaneous br of median n (ulnar to FCR, arises ~5cm proximal to wrist joint); radial artery (just radial to FCR); volar capsule wrist ligaments (avoid releasing - can cause instability)

Question 3

Ulna approach

Question 4

Dorsal Radius Approach

Answer 4

Thompson Approach

• Incision: anterior to lateral epicondyle of humerus to just distal to ulnar side of Lister’s tubercle
• Interval: ECRB (radial)/EDC (PIN) proximally, EPL (PIN) distally
• Superficial dissection: plane between ECRB and EDC (can find distally where APL and EPB emerge between the two; proximally ECRB and EDC share a common aponeurosis)
• Deep dissection:
• proximal 1/3: supinator covers radial shaft; ID and protect PIN either distal to proximal or proximal to distal
• proximal to distal: detach ECRB and part of ECRL origins from lateral epicondyle and retract laterally, ID PIN by palpation (proximal to edge of supinator) and dissect out of substance of muscle
• distal to proximal: ID PIN as it emerges from supinator ~1cm proximal to distal edge of muscle, dissect out proximally
• supinate forearm and detach supinator insertion from anterior aspect of radius
• Middle 1/3: APL and EPL cross dorsal aspect of radius, heading distally and radially; incise superior and inferior borders and retract either distally or proximally to expose radius below
• Distal 1/3: lateral border of radius already exposed between ECRB and EPL
• Dangers: PIN - ID and protect using methods outlined; touches periosteum on dorsal aspect of radius in 25% of people…

Question 5

Dorsal Wrist

Answer 5

Compartments 3 and 4

• Incision: dorsal incision midway between radial and ulnar styloids from ~3cm proximal to joint and extending ~5cm distal to joint
• Interval: no true internervous plane, between 3rd and 4th extensor compartments (EPL, EIP/EDC)
• Superficial dissection: expose extensor retinaculum
• Deep dissection: release EPL (3rd compartment) and retract radially; subperiosteally elevate 4th compartment (EIP/EDC) and retract ulnarly
• to expose carpus incise capsule longitudinally, retract tendons of ECRL and ECRB (lying in tunnel on radial side of Lister’s tubercle) radially to fully expose carpus

Question 6

Volar Approach to the Carpals

Answer 6

• Incision: from just ulnar to thenar crease (in line with radial border of 4th MC) to ~1/3 of the way into hand (~4cm or to Kaplan’s cardinal line); curve ulnarly across wrist crease and end ~3cm proximal to wrist crease
• Interval: no true internervous plane, no muscle dissection
• Superficial dissection: sharply divide skin, then begin blunt dissection of subcutaneous tissues, watching for palmar cutaneous br of median n (usually found on ulnar side of FCR); expose palmaris tendon and superficial palmar fascia (divide fascia in line with incision)
• ID palmaris tendon (retract ulnarly) and transverse carpal ligament (flexor retinaculum); ID median nerve between palmaris longus and FCR tendons
• Insert blunt flat instrument between transverse carpal ligament and median nerve, then divide ligament (on ulnar side of nerve to avoid damage to recurrent motor branch which may pass through ligament)
• Deep dissection: ID motor recurrent br of median n (anterolateral side of nerve as it emerges from carpal tunnel); may have to decompress this too if aberrant anatomy and compression (e.g. if it emerges through retinaculum etc.)
• if access to wrist joint is needed, mobilize and retract median n radially, then mobilize and retract flexor tendons and incise base of carpal tunnel to expose carpus
• Dangers: palmar cutaneous br of median n (arises ~5cm proximal to wrist, runs along ulnar side of FCR, then crosses retinaculum (protect by angling incision to ulnar side of forearm proximally); motor recurrent br of median n - watch for anatomic variants and incise flexor retinaculum on ulnar side of median n

Question 7

Volar Approach to Ulnar Nerve

Answer 7

• Incision: curved incision (~5-6 cm long) following radial border of hypothenar eminence and crossing wrist crease obliquely
• Interval: no true internervous plane, no muscle dissection
• Superficial dissection: ID FCU tendon proximally and mobilize (by incising fascia on radial border) and retract ulnarly to reveal ulnar nerve and artery

Question 8

Volar approach to scaphoid

Answer 8

Waist and distal scaphoid fractures

• Incision: 3cm incision centred over scaphoid tubercle (from distal aspect FCR and curving toward base of thenar mass)
• Interval: no true internervous plane, no muscle dissection
• Superficial dissection: ID FCR tendon, incise sheath and retract ulnarly
• Deep dissection: longitudinal arthrotomy in radiocarpal joint, curve transversely to open STT joint
• Dangers: radial artery just radial to FCR tendon