Microsurgery Flashcards
What are the goals of tx of fingertip amputations?
What is the prognosis for tx?
- Sensate Tip
- Durable Tip
- Bone support for nail growth
Prognosis
- Improper tx may result in stiffness adn longterm functional loss
Can you draw/describe the anatomy of the finger tip?
- Eponychium- soft tissue on dorsal surface just proximal to nail
- Paronychium- lateral nail folds
- Hyponychium- plug of kerabtinous material situated beneath the distal edge of nail where nail bed meets skin
- Lunula- white portion of proximal nail, demarcates sterile from germinal matrix
- Nail bed
- Sterile matrix- nail adheres to nail bed
- Germinal matrix- proximal to sterile matrix, responsible for 90% nail growth
What is the aetiology of amputation?
- Avulsion
- Laceration
- Crush
What do you see on examinatio of an amputated finger tip?
- Characteristics of laceration
- presence/absence of exposed bone
- range of motion- felxor/extensor involved
What investigations useful for amputation of finger tip?
- Xray- ap and lateral to assess Bony involvment
Describe the tx of finger tip amputations?
Non operative
- Healing by secondary intention
- adults/children with no bone/tendon exposed with <2cm skin loss
- children with exposed bone
Operative
-
Primary closure- revision amputation
- finger amputation w exposed bone and ability to rongeur bone proximally without compromising bony support to nail bed
-
Full thickness skin graft from hypothenar region
- Fingertip ampuation with no exposed bone and >2cm tissue loss
-
Flap Reconstruction
- exposed bone/tendon where reongeuring bone proximally is not an option
Describe the technique for secondary intention?
- initial tx with irrigation and soft dressing
- After 7-10 days saok in water-peroxide solution daily followed by application of soft dressing adn fingertip protector
- complete healing takes 3-5 weeks
Describe the technique for full thickness skin grafting from hypothenar region?
-
Split skin grafts not used as
- Contractile
- Tender
- Less Durable
- Donor site is closed primarily
- Graft is sutured over defect
- Cotton ball secured graft helps maintain coaptation with underlying tissue
- Ball removed after 7 days
- Range of motion encourage after 7 dyas
Describe the technique for revision amputation?
Primary closure with removal of exposed bone
-
Must ablate remaining nail matrix
- prevent formation of irrating nail remnants
- If flexor/extensor tendon insertions can’t be preserved disarticulate at DIPJ
- transect digtial nerves and remaining tendoms proximal as possible
- Plamar skin is brought over bone and sutured to dorsal skin
Can you describe the flap types available for Finger tip- to DIPJ ?
- Straight/Dorsal Oblique lacerations
- V-Y Advancement
- Digital Island Artery- best axial pattern flap
-
Volar Oblique laceration
- Cross finger Flap if >30 yrs- less stiffness
- Thenar Flap if <30 yrs- improved cosmesis
- Digital Island artery
Can you describe the types of flap available for volar proximal finger?
- Cross finger flaps if > 30 years
- Axial flag flap from long finger
- Leads to less stiffness - X finger flaps
Can you describe the types of flap available for dorsal proximal finger and MCP lesion?
- **Reverse Cross FInger **
- Axial FLag flap from long finger
Can you describe the types of flap available for volar thumb lesion?
- Moberg Advancement Volar flap if <2cm
- First Dorsal Metcarpal Artery flap FDMA if >2cm
Can you describe the types of flap available for dorsal thumb lesion?
- First Dorsal Metacarpal Artery Flap
Can you describe the types of flaps available for first web space lesions?
- Z plasty with 60 degree flaps
- can increase length by 75%
- Posterior interosseous fasciocutanoeous flap
Can you describe the flaps types available for dorsal hand?
- Groin flaps
What are the complications of flaps?
-
Flap failure
- inadequate blood flow
- vasospasm -> thrombosis at anastomosis
-
Hook nail deformity
- Tight tip closure
- insufficient bone support
What is the epidemiology of upper extremity amputations?
- Trauma
- 90% occur after trauma
- 4:1 male cf female ration
- most occur at level of digits
- mechanism of traumatic amputation
- Sharp dissection
- Blunt dissection
- Avulsion
- Crush
What is the imortant history and signs of amputation?
Hx
Timing of injury
- type & location of amputation
- preservation of amputated tissue
- PMhx
O/E
- Stump examination
- zone of injury/ tissue viability/supporting tissue structures/contamination
- Amputated portion inspected
- level, segemental injury/ bone/soft tissue damage/ contamination
What are the indications for replantation post trauma?
Primary
- Thumb
- Multiple digits
- wrist level or proximal wrist
- Almost all parts in children
Relative
- Individual digits distal to the insertion of Felxor digitorium superficialis- zone 1
What are the contra- indications for replantation post trauma?
Primary
- Single digit proximal to FDS - zone 2
- mangled limb/crush injury
- Semgental amputation
- prolonged ischaemic time
relative
- Medically unstable patient
- disabling psychiatric illness
- tissue contamination
Describe the transport of amputated tissue?
- Keep with patient
- Wrapped in gauze in lactate ringers solution
- Placed in sealed plastic bag and placed in ice water- avoid direct contact with ice/dry ice
- Wrap, cover and compress stump wiht moisten gauze
Describe the time to reimplantation?
-
proximal to carpus
- warm ischaemic time <6 hours
- cold ischaemic time <12 hrs
-
Distal to carpus ( digit)
- warm ischaemic time <12 hours
- Cold ischaemic time <24 hrs
Can you describe the operative sequence of replantation?
- Bone
- extensor tendon
- Flexor tendons
- Arteries
- Veins
- Nerve
- Skin
BEFAVNS
Can you describe the finger oder for reimplantation?
- Thumb
- Middle
- Ring
- Small
- Index
How is reimplantation achieved for mutliple digits?
- Structure by structure most efficient
- Digit by digit takes the most time
Describe the post operative care for reimplantated digits?
-
Environment
- Warm 80F
- avoid caffine, chocolate, nicotine
-
Monitor replant
- Skin temperature- most reliable, concern >2o drop in < 1 hour or temp below 30oC
- Pulse oximetry <94% - vascular compromise
-
Anticoagulation
- adequte hydration
- medications aspirin, heparin
-
Arterial insufficiency
- release constriction bandages
- place extremity in dependent position
- consider heparinisation
- consider stellate ganglion blockade
- early surgical exploration
- thrombosis secondary to vasospasm is most common cause of early implant failure
-
Venous congestion
- elevate extremity
- leech application
- release Hirudin- powerful anticoagulant
- aeromonous hydrophila infections can occur
- Heparin soaked pledgets if no leeches
Describe the complications of reimplantiation?
-
Reimplantation failure
- within 12 hrs- arterial thrombosis from vasospasm
-
Stiffness
- 50% of total motion of normal digits
- tenolysis is most common secondary procedure
-
Myonecrosis
- > in major limb reimplantation cf digit
-
Myoglobinuria
- muscle necrosis in larger implants
- can lead to renal failure-> fatal
-
Reperfusion injury
- ischaemia induced hypoxanthine conversion to xanthine
- Allopurinol to decrease xathine production
- Infection
- Cold intolerance
What is the most important factor in influencing immediate and late outcome of amputations?
- Type of Injury
Describe the regions of thumb reconstruction?
- Region A
- Primary closure
- Toe to thumb
- local flaps
- Region B
- Web Deepening
- Metacarpal lengthening
- Toe to thumb
- Region C
- Toe to thumb
- Osteoplastic thumb reconstruction
- Dorsal rotational flap
- Region D
- Pollicization
What does thumb reconstruction require?
- An intact CMCJ that is stable but also **appropriately functional **
Describe the different tx of thumb reconstruction?
-
Toe to thumb procedure
- Great toe recieves blood supply from 1st dorsal metatarsal artery & dorsalis pedis
- morrison/wrap around allows for maintaince of length if hallux. Size and appearance are best replicated.
- 2nd MT is not suitable for transfer
-
Web Deepening
-
Z plasty ( 2/4 flaps)
- 2 flaps provide > depth
- if complete at 45o - relative length increase by 50%, 60o 75%
-
Brand Flaps
- Index finger used to provide a full thickness
- can close donor site primarily
-
Dorsal rectangular flaps
- taken from dorsum of metacarpals
- may require skin grafting
-
Arterilalized palmar flap
- may use axial ( local) or island flap ( distal)
-
Z plasty ( 2/4 flaps)
-
Osteoplastic reconstruction
- iliac crest is used to establish mechanical length to the thumb
- an island flap from the radial aspect of the 4th ray is combine dwiht reverse radial forearm flap to aid coverage.
What is ring avulsion injuries?
- Sudden pull on a ring finger results in severe soft tissue injury ranging from circumferential soft tissue laceration to complete amputation
- Skin. nerves , vessels are often damaged
Describe the epidemiology of ring avulsion injuries?
- Incidence 150,000 incidents of amputation & degloving in us pa
- 5% of upper limb injuries
- Usually involves one digit - ( ring)
- Risk factors
- working with machinery
- wearing a ring
What is the aetiology of ring avulsion injuries?
- Patients catch wedding ring or finger on moving machinery or protruding object
- Long segment of MACRO & MICRO Vascular injury from crushing, shearing and avulsion
What is the prognosis of avulsion injuries?
- Outcomes of injury
- Extent of injury is greater than what it appears
- Poor prognosis because of long segment vascular injury
- Outcomes of tx
- Advances in interposition graft techniques have improved results with ring avulsion replantation
How long will avulsed digits last for?
- As devoid of muscle avulsed digits will survive >12 h if cooled
- Skin is the strongest part - once torn the remaining tissue quickly degloves
Can you describe the name and classification system of ring avulsion injuries?
- Urbaniak Classification
- Class 1= (80N) Circulation adequate->standard bone and soft tissue care
- Class 2-=Circulation inadequate-> vessel repair
- Class 3= ( 154N)Complete degloving or complete amputation-> amputation
what are the signs and symptoms of ring avulsion injury?
- Hx
- work with machinery, caught in door
- Symptoms
- Pain
- Bleeding
- Lack of sensation at tip
- OE
- Inspect- irrigate wound adn inspect for avulsed vessels, damaged tendons, nerves, skin edges
-
Staggered injury pattern
- prox skin avulsion from pipj->base of digit
- Distal bone fracture or dislocation- distal to pipj
What investigations are helpful in dx of ring avulsion injuries?
- Xrays of both parts as amputated part may have bone!
Describe the tx of ring avulsion injuries?
- Initally
- Place amputated part in bag with saline moistened gauze , follwed by bag of ice
- Antibiotics and tetanus prophylaxis
Operative
-
Reimplantation +/- Vein graft, DIPJ fusion
- for disruption of venous drainage
- disruption of venous/ arterial flow- revascularisation
- Intact PIPJ & FDS insertion
- Complete ampuation ( esp distal to PIPJ/FDS is relative CI to reimplantation
-
Revision Amputation
- complete degloving
- bony injury with nerve and vessel injury
- bony amputation proximal to FDS or proximal to PIPJ
- reimplantation likely-> poor hand function
- consider revision amputation/ray amputation
What are the outcomes of replantation+/- vein graft , dipj fusion for ring avulsion injuries?
- Survival
- lower survival for avulsed digits 60% cf finger reimplantation in general 90%
- Lower survival for complete 66% vs incomplete avulsion replantation
-
Lower survival for avulsed thumb than finger
- surgeons attempt technically difficult rhumb where conditons are not favourable cf digits
- Sensibility
- most achieved Protective Sensibilty 2PD 9mm
- Better sensibility when incomplete avulsion replantation than complete
- Range of motion
- Average total arc of motion (TAM) is 170-200
- better TAM in incomplete avulsion implantation than complete
Describe the technique for reimplanatation/revascularisation?
- under microscope
- lateral incision on ulnar aspect
- arteries
- thorough debridment of non viable tissue
- thorough arterial debridment
- repair using vein graft-significant damage
- may need another step- down vein graft because of difficutly of matching sizes
- may reroute arterial pedicle from adjacent digit
- Veins
- repair at least 2 veins
- important factor in revascularization failure
- Bone
- If amputation at DIPJ , preform primary arthrodesis DIPJ
-
Skin
- Preform FTSG or venous flap to prevent tight closire
Describe the complications for replantation?
- Cold Intolerance
-
Revascularization/replanatation failure
- Sig factors is repair of <2 veins
- Vascular damage to digital pulp
- smoking and level of bione injury not been found to effect survival
- Flexion Contracture
- Malunion
- revision surgery
- revision amputations-> Hyperaesthesia
