Replants

Replant 4 FingersReplant 4 fingers post

 

Definition

 

Replant

 

Reattachment of body part that has been completely severed

 

Revascularisation of incomplete amputation

 

Vascular repair is necessary to prevent necrosis of the extremity

- retains some venous and lymphatic drainage albeit small

- revascularisation easier, quicker and better results

 

Mechanism of injury

 

Guillotine

Crush

Avulsion

 

Incidence

 

Friedrich et al J Hand Surg Am 2011

- 9400 upper extremity amputations

- 14.5% underwent replantation

- 27% thumbs, 12% digits, 12% hands or forearms

 

Indications for surgery

 

Thumb 

 

Multiple digits

 

Individual digit distal to FDS insertion

 

Partial hand / through palm - replant far superior to prosthesis as lose sensation and power grasp

 

Almost any body part in child

 

Wrist or forearm

 

Above or below Elbow - only if sharply demarcated

 

Contra-Indications

 

Adult single digit proximal to FDS insertion

- poor results / stiffness

 

Ischaemic time distal to carpus

- > 12 hours warm ischaemia time

- > 24 hours cold ischaemia time

 

Ischaemic time proximal to carpus

- > 6 hours warm ischaemia time

- > 12 hours cold ischaemia time

 

Severe crush or mangled

 

Levels

- through elbow

- high arm

 

Multiple level / segmental injury

 

Other serious injuries / comorbidities

 

Transport of amputated part

 

4oC ideal

 

2 Methods

 

1. Wrapping the part in a moistened cloth of Ringer's or Saline

- placing in plastic bag and placing the bundle in ice water

 

2. Immersing the part in one of these solutions in a plastic bag 

- then putting on ice

 

No difference in outcome

 

Most important is to give clear and precise instructions to referring doctors

 

Ischaemia

 

Key factor in success

Duration of allowed ischaemia varies from tissue to tissue

 

Recommended maximum

 

1.  Distal to carpus 

 

12 hours warm ischaemia time

24 hours cold ischaemia time

 

Digits consist of skin, bone and subcutaneous tissue

- no muscle

- warm ischaemia tolerated for long periods

- freezing not tolerated

- digits have survived for 12 hours or longer of warm ischaemia

- when cooled replants have been successfully performed at 36 hours

 

2.  Proximal to carpus 

 

6 hours warm ischaemia time

12 hours cold ischaemia time

 

Major limb replants contain large volume of muscle

- only tolerate 4-6 hours of ischaemia

- because of the size of the extremity only its outer part is adequately cooled 

- the deep muscle remains relatively warm

- the allowable 6 hours warm ischaemia time can't be extended

 

Patient factors

 

High demand professionals

- may push indications

- i.e. amputation at level of proximal phalanx

 

Patient must be aware of chance at viability, function, time off work etc

 

Premorbid conditions must be taken into account 

- diabetes, smoking, peripheral vascular disease

- patient compliance

 

Surgeon

 

Should be able to consistently achieve 90% patency rate in 1mm vessels in laboratory

 

Digits

 

Digit 1Digit 2Digit 3

 

Single digit

 

Distal to FDS tendon insertion replant

- outcomes good

- able to immediately mobilise of digit

 

Proximal to FDS tendon insertion replant

- useful function does not occur

- patient will bypass finger

 

Multiple digits

 

Concept

- replant best digit to most useful stump

- when thumb intact goal is to restore palm width

 

Kaneshiro et al J Plast Reconst Aesthet Surg 2020

- retrospective review of 12 patients undergoing multiple digit replantation

- mean 2.8 digits replanted, survival 87%

 

Results

 

Survival

 

Shaterian et al J Hand Microsurg 2018

- systematic review of 32 studies with > 6000 digit replantations

- increased survival rates with 2 (90%) versus 1 (84%) arterial anastomoses

- increased survival rates with 2 (92%) versus 1 (73%) versus 0 (61%) venous anastomoses

- increased survival with sharp injuries (87%) versus crush (70%)

 

Function

 

Shaterian et al Hand 2021

- systematic review of 28 studies with 618 digit replants

- average grip strength 80% contralateral limb

- average two point discrimination 8 mm (normal 2 mm)

- average DASH score 12 (0 - no disability, 100 - severe)

 

Operative technique for single digit

 

Sequence

1. Locate and tag vessels and nerves

2. Debride

3. Shorten and fix the bone

4. Repair extensors

5. Repair flexors

6. Anastomose the arteries

7. Repair the nerves

8. Anastomose the veins

9. Obtain skin coverage

 

Technique

 

Set up

- maintain body temperature by warming the patient

- axillary block to block sympathetics

- ABx, tetanus prophylaxis

- in dwelling catheter

 

Approach

- longitudinal mid-lateral incisions for digital replants

 

Shorten bone

- get out of zone of injury 

- must have no tension on the grafts

- minimum 0.5 - 1 cm each side

- alternative is to vein graft but is easier to shorten bone

- shortening also helps with skin coverage

- ORIF proximal phalanx

- K wire DIPJ / distal phalanx

 

Extensor Tendons

- primary repair

- if inadequate extensor tendon for primary repair perform delayed repair

 

Flexor tendons 

- repaired primarily if at all possible

- otherwise 2 stage 

 

Arterial repair

- 9/0 or 10/0 nylon interrupted

- key is repair normal intima to normal intima

- adventitia is intensely thrombogenic so ensure none in repair

- strip adventitia for 1-2mm

- repair both arteries if possible otherwise consider reversed vein graft

- tourniquet acceptable

- micro-clips / bulldog clips should not be applied > 30 min due to intimal damage

- heparin boluses to maintain patency (5000IU in 500 mls)

- papaverine antispasmodics

 

Vein repair

- 2 veins for every artery

- can consider removing nail bed + heparin soaked dressings to allow bleeding

 

Nerve repair

- 10/0 interrupted epineural repair

- primary repair if possible

- primary nerve graft or conduit

- use medial cutaneous nerve of forearm 

 

Skin

- skin closed under no tension

- digital incisions often left open to decompress repairs

 

Postoperative management

 

Elevate in gallows

- high dependency area

- appropriate intravenous fluids

- anticoagulation controversial - usually heparin boluses given

- smoking strictly prohibited

- no caffeine

- warm ambient temperature

- observations hourly for 72h then q4h

 

Assessment of vascularity

 

Colour / capillary refill

 

Oxygen saturation probe

 

Surface temperature <30°C indicates that poor perfusion of the replant is certain

 

Pinprick

- bright red bleeding normal

- dark blue blood venous congestion

 

Failing replantation

 

If appears threatened immediate action is necessary

1. Relieve dressings or sutures

2. Either elevate or dependant position

3. Regional block for sympathetics

4. Relieve pain, fear and anxiety

5. Ensure patient warm and adequately hydrated

6. Intravenous heparin

7. Consider medical leeches for venous congestion

8. If return to OT is necessary then must be within 4-6 hours of ischaemia

 

Thumb replant

 

Thumb 1Thumb 2Thumb 3

 

Background

 

Thumb has first priority

 

A successfully replanted thumb is always better than any reconstruction

- thumb provides 40% of hand function

- a fixed stump / post is very useful

 

Level

 

Detipped thumb can be successful

- need dorsal veins in stump

- need 4mm of skin proximal to nail plate

- all efforts should be made to preserve thumb length 

 

Thumb detipThumb detip 2Thumb detip xray

 

Technique

 

Ulnar sided artery larger

Need to adduct shoulder / internally rotate arm

Can fuse IPJ

 

Salvage

 

Lin et al Hand 2011

- systematic review of toe to thumb transfer for traumatic thumb replantation

- 25 studies, 450 cases

- 101 second toe transfers

- 196 great toe transfers

- similar outcomes

 

Ring Avulsions

 

Finger avulsion 1Ring avulsion 2Finger replant 3

 

Definition

 

Circumferential skin loss of finger caused by traumatic injury to ring

 

Urbaniak Classification

 

Bamba et al Hand 2018

- systematic review

 

Type I

- circulation adequate

- may involve damage to flexor / extensor tendons

- 9% of injuries

- typically good results

 

Type II

- circulation inadequate

- typically microvascular repair less simple

- can be large zone of injury

- vascular grafts or venous flaps may be required

 

Type III

- complete degloving or complete amputation

- 84% survival with replantation

- worse outcomes with regards range of motion and two-point discrimination

 

Midcarpal Replantation

 

Replant 4 FingersHand replant 1Hand replant 2

 

Replant 4 fingers postHand Replant 3

 

Major Limb Replantation

 

Definition

 

Proximal forearm / elbow joint / arm 

 

Issues

 

1. Usually avulsion or crush injuries types with extensive muscle injury

 

2. Amputations proximal to metacarpal level have significant muscle bulk

- high risk of myonecrosis and subsequent infection

- immediate arterial inflow is necessary

- need patient hydration and osmotic diuresis to protect kidneys

 

3. Functional outcome related to level of amputation

 

Technique

 

Rapid skeletal stabilisation

- at least one artery must be revascularised

- then follow sequence for digit

- extensive fasciotomies always indicated

- any exposed vessels must be covered by rotation flap etc

 

Results

 

Ramji et al Plast Reconstr Surg Global Open 2020

- systematic review of 13 studies with 136 major limb replantation

- functional outcome related to level

- good to excellent outcome scores distal to elbow

- poor outcomes at or proximal to elbow