CHAPTER 12: HAND - REPLANT, THUMB RECONSTRUCTION AND FINGERTIP INJURIES Flashcards
Who were the pioneers of replantation?
1st successful arm: Malt 1964 (Boston)
incompletely severed digits: Kleinert Kasdan 1965
1st successful digital replant: Komatsu & Tamai 1968
Define:
- Replantation
- Revascularisation
- Macroreplantation
- Microreplantation
- Replantation = reattachment of totally amputated parts.
- Revascularisation = repair of incomplete amputations.
- Macroreplantation
∘ amputated part contains muscle, which necroses after 6 hours of warm ischaemia or 12 hours of cold ischaemia. - Microreplantation
∘ digits are more resistant to ischaemia (at least 12 hours of warm ischaemia or 24 hours of cold ischaemia).
What are the pertinent points in history?
- age, hand dominance, occupation, hobbies
- pre-existing hand problems
- mechanism of injury
- ischaemia time, storage of amputated part
- smoker?
- tetanus status
What are the contraindications of replant?
Absolute
- life-threatening concomitant injuries
- multi-level injury
- severe premorbid illness
Relative
- single digit amputations,
- zone II,
- inadequate venous anastomoses (need 4mm proximal to nail fold)
- degloved
- avulsion of tendons, nerves, vessels (‘red streak sign’ = bruising over NV pedicle, ‘ribbon sign’ = corkscrew appearance of vessels).
- extreme contamination / crush
- warm ischaemia time (digit >12hrs, arm >6hrs)
- elderly, micro-arterial disease, heavy smokers, severe systemic / psychiatric disease
What are the indications for replant?
- Thumb
- Child
- Multiple digits
- Partial / whole hand
- Wrist, forearm, elbow and above elbow
- Single digit distal to FDS insertion (zone 1 better outcome than zone 2)
- Patients who ‘must’ have a 10-digit hand, e.g. musicians.
What is the arterial supply to the hand?
Ulnar - superficial palmar arch - common - radial and ulnar digital arteries
Radial - deep palmar arch - deep to flexor tendons
UDN dominant - thumb, index, middle
RDN dominant - ring, little
Arterial grafts may be needed for: long revasc time (e.g. radial artery to thumb)
What classifications do you know for ring avulsion injuries?
Urbaniak 1981
Class 1 - no vascular compromise, with soft tissue injury
Class 2 - vasc compromise, microvascular reconstruction will restore circulation and function. (ABC added by others)
A - digital arteries only
B - arteries + tendon, bone, nerve
C - veins only
Class 3 - complete degloving / amputation, circumferential laceration (replant unlikely to be successful)
What is Simon Kay’s classification of ring avulsion injuries?
Kay et al., JHS 1989, 14A, 204-13
I Circulation adequate, without skeletal injury
II Circulation inadequate, without skeletal injury
IIA Arterial circulation inadequate only
IIV Venous circulation inadequate only
III Circulation inadequate, with fracture or joint injury
IIIA Arterial circulation inadequate only
IIIV Venous circulation inadequate only
IV Complete amputation
What is noted on examination?
Trauma - ATLS principles
Amputated part - degree of crush / avulsion
X ray - concomitant injuries
Consent for graft harvest (vein, tendon, skin) and terminalisation
What can be done if there are no artery / vein available?
What other procedures may be considered?
If no suitable artery available:
• Interposition vein grafts (e.g. volar wrist) or vessel transposition from adjacent finger.
• Grafts can be placed extra-anatomically to radial artery at the wrist.
• If no suitable dorsal veins available:
1. Repair any volar veins.
2. Anastomosing a digital artery (which has backflow) to a vein, creating an arteriovenous
fistula.
3. Remove nail plate and scrape sterile matrix to encourage bleeding with heparin-soaked gauze.
4. Periungal incision and topical heparin.
5. Medical leeches.
Consider: carpal tunnel decompression, soft tissue cover, nerve, vein grafts.
Major limb - fasciotomies, proximal carpectomy (hand)
What are the special considerations in macro replantation?
- Temporary vascular shunt, such as a Sundt, Pruitt-Inahara or Javid shunt is priority.
- Bone shortening (makes primary vessel and nerve repair easier).
- Fixation of bone
- Definitive arterial repair.
- Allow venous bleeding from amputated part to flush out toxic metabolites (+ blood transfusion).
- Fasciotomies are always indicated.
- Assess for further muscle necrosis within 48–72 hours.
How do you perform a digital replant?
GA, brachial block (vasodilatation and postop analgesia), arm tourniquet, image intensifier, 2 team approach.
Team 1:
- Examine + XR amputated part before pt is GA’d,
- Mid axial incisions, tag NVBs,
- Shorten bone ~5mm, fix with Kwire / IO wires / box 90-90 / miniplates and screws.
Team 2: Debride stump, tag NVBs. Order of repair: Bone extensor flexor digital nerve digital artery digital vein skin cover
Consider: carpal tunnel decompression, soft tissue cover, nerve, vein grafts
Major limb - fasciotomies, proximal carpectomy (hand)
What are the post-operative considerations?
- POSI splint
- warm, wet, pain-free
- elevation 45 degrees
- flap obs
- axillary block (vasodilation and analgesia)
Drugs
- aspirin
- heparin
- antibiotics
- chloropromazine (peripheral vasodilator and sedative)
What are the complications of replant?
failure infection CRPS I pain stiffness swelling cold intolerance atrophy
How do you treat a struggling replant?
Re-explore, vein grafts to artery
Inflow - ensure pt is well filled, analgesed - loosen dressings, If doubt about patency, plan for early exploration 1. Loosen dressing. 2. Warm finger. 3. Remove sutures 4. Use antispasmodic drugs. 5. Improve pain control. 6. Use bupivacaine block (vasodilation). 7. Use heparin.
Outflow
- as above
1. Increase elevation.
2. Loosen dressing and sutures.
3. Use systemic heparin.
4. Remove nail plate with heparin-soaked pledgets.
5. Use leech therapy.
6. Return to theatre.
What are the functions of the thumb?
40% of hand function
- key pinch
- tripod pinch
- power grip
What are the options for thumb reconstruction?
Distal 1/3
Homodigital
- Moberg (1.5cm advancement)
Heterodigital
- cross-finger
- Foucher (1st DCMA flap)
- Littler (ulnar pad of middle / radial ring)
- Kite
Free
- toe pulp transfer (medial hallux)
What are the options for thumb reconstruction?
Middle 1/3
- 1st web deepening
- pollicisation
- distraction osteogenesis
- toe-hand transfer
- bone graft
Prox 1/3
- pollicisation
- free toe-thumb
Tell me about toe to thumb transfer
donor site
- 1st DMCA: mark from DP pulse to 1st web of foot
- superficial dorsal - GSV
- volar digital nerves (medial plantar nerve)
- leave 1cm of hallux PP for push-off
What are the different toe transfers?
(A) Great toe - 20% bigger than thumb
(B) 2nd toe - thinner
(C) Wrap around (Morrision) - taking soft tissue + nail from hallux w/o bone
(D) Trimmed great toe (Wei) - toe is trimmed to size of thumb including longitudinal osteotomy
(E) Partial toe transfer (2nd toe: e.g. MTPJ, pulp, skin, nail)
Systematic review (Chung et al, Hand 2011) - no difference in outcome between A-D (96.4% successful), with regards to survival, grip + pinch strength, TAM, arc of motion or 2PD.
What is your algorithm for thumb reconstruction?
Thumb amputation
- IP level
- pulp transfer
- great toe wrap-around flap (Morrison 1980 - great toe degloved, modified to part of DP preserved) - B/t IPJ + 1st MC neck level
- great toe
- trimmed toe transfer (Wei 1988 - medial great toe trimmed) - Proximal amputation
- Tsai’s technique (1991 - compound wrap-around flap harvested from great toe and vascularized joint transfer from 2nd toe based on same pedicle)
- bone graft and great toe transfer
- extended second toe transfer
Digital reconstruction
- Wide volar skin defect
- 1st web flap - lateral digital artery of great toe and medial digital artery of 2nd toe from FDMA or FPMA, depending on dominant pattern.
Single-digit amputation or avulsion injury
- St / distal to PIPJ
- single 2nd/3rd toe transfer
- 2nd toe wrap-around flap
Multiple digit amputation
- Distal to MPJ
- double toe transfer
- split combined toe transfer - At or proximal to MPJ
- combined toe transfer
What are the anatomical landmarks of the 1st dorsal metatarsal arteries?
Describe the procedure of toe to hand transfer.
1- Mark arterial axis - from palpable DP pulse to 1st web
2- veins and joints marked
3- spare superficial peroneal nerve
4- make a v shaped flap at base of toe, and determine if FDMA is dominant (70%) c.f. FPMA (20%)
5- dissect out superficial vein
6- dissect out and divide EHL
7- retrograde dissection of FDMA to DP, ligating collaterals
8- dissect out medial branch of deep peroneal nerve (to lateral big toe)
9- dissect out digital nerves (plantar), ligate FPMA
10- divide FHL
11- perform osteotomy (ideally preserve 1cm of prox phalanx to maintain attachment of plantar aponeurosis and intrinsic muscles in foot)
What is the classification of fingertip amputations
Type I
- only soft tissue
TYPE II
- up to middle third of the nail
- nail growth usually straight
Type III
- up to the nail fold
- hook-nail deformity (inadequate bony support)
Type IV
- DIPJ
What flaps are used for fingertip injuries?
HOMODIGITAL
- Atasoy
- Venkatswami v Segmuller
- Venkatswami does not cross midline
- Segmuller does - Cutler – ‘is evil’
- Moberg – thumb
- Step Advancement – David Evans and David Martin (1988)
- Merle – homodigital volar adipofascial to dorsum – modified by Pickford
- Reverse homodigital island flap
HETERODIGITAL
- Littler - Ulnar Middle to volar thumb, or from radial ring finger
- Quaba (1990) - distally based flap from perforator b/t 2nd DMCA + palmar vessel running in second WS
- Foucher (1979) - 1st dorsal metacarpal artery
- Cross finger flap
- Flag flap
