Grafts and Flaps in Surgical Practice

Grafts and Flaps in Surgical Practice

Introduction

• These are vital tools in surgery , especially in reconstructive surgery

• Adequate patient assessment

• Appropriate choice and application

• Avoid abuse

• Always have a back up plan

FLAPS AND GRAFTS

• QUANTITY

• PROTECTION OF VITAL STRUCTURES

• FUNCTIONAL RESTORATION

• NEED FOR UNRESRICTED MOBILITY

• NEED FOR REOPERATION

• WILL MY COVER AFFECT FURTHER MGT

• FLAP

• GRAFT

• NEED TO IMPROVE BLOOD SUPPLY

• WHAT COMPONENTS MUST BE

• RESTORED?

• TISSUE PADDING / CONTOUR

• EFFECT OF WOUND CONTRACTION

• ADNEXIAL REQUIREMENTS

• DONOR SITE MORBIDIT

• COSMESIS

Grafts

• Transplant of a tissue from the donor site where it detached from its blood supply to the recipient site where blood supply is regained by vascular in growth

• Types skin graft, bone graft, tendon graft, nerve graft, cartilage graft, vein graft, composite graft

Skin graft

• Types

• Depending on the donor
• Autograft
• Allograft
• Xenograft
• Isograft
• Depending on thickness of dermis
• split thickness skin graft thin[0.2 0.3mm], intermediate thickness[0.3 0.45mm], and thick [0.45 0.75mm]
• Full thickness skin graft

Indications of skin graft

• Skin loss post traumatic[avulsion, degloving ], post surgical [excision of tumours and lesions], as a result of pathological process venous ulcer

• Mucosal loss after excision of leukoplakic patch, resurfacing reconstructed vagina in agenesis

Contraindication

• Avascular recipient areas

• Infection

Flaps

• Flap A composite block of tissue with its own blood supply
  
  
  

• Pedicled flap Transplant of tissue from one part of the body to another with its blood supply intact

• Perforator flap A flap based on a visible musculocutaneous or septocutaneous perforating vessel that is dissected free from surrounding muscles to obtain the desired length

• Free flap Tissue that is transferred from one part of the body to another and revascularization achieved by microvascular anastomoses to recipient vessels

• Chimeric flap A flap comprising of separate components ultimately supplied by the same source vessel.

• Delay A planned initial manoeuvre to partially interrupt the blood supply of a flap before moving it to a new position at a later date, This facilitates the opening up of ‘choke’ vessels, reorientation of existing flap vessels and the sprouting of new vessels within the flap which improves the flap’s ultimate blood supply

• Crane principle A technique to convert an ungraftable bed into a graftable bed . It involves transferring a flap into a defect, and after a period of time returning the superficial portion of the flap to its original position, minimizing the aesthetic defect and allowing the remaining now graftable bed to be skin grafted

• Z plasty A technique involving the transposition of two triangular flaps, allowing elongation, realignment, and breaking up of astraight scar.

Blood supply to skin

• Skin receives its blood supply via

• direct cutaneous system
• indirect system through ; septocutaneous, fasciocutaneous and musculocutaneous systems

• Angiosome concept segregation of the body anatomically into three dimensional vascular territories

• Anatomical territory anatomical territory of a vessel is the area occupied by the vessel and its ramifications before anastomosing with adjacent vessels. Defined on the basis of anatomical dissection

• Dynamic territory dynamic territory of a vessel is the area supplied by the vessel after the surrounding anastomosing vessel are divided and ligated . Dynamic territory is always greater than the anatomical territory

• Potential territory - Potential territory is the area of the skin which can be raised with an axial pattern flap beyond the dynamic territory as random extension. This requires preliminary delay of potential territory 7 - 10 days prior to raising the flap

Contouring - Advancement, rotation, trans

[ type of movement] position, interpolation

Conditioning - Delay

Flaps

• 2 broad groups

• free flaps
• pedicled flaps

• Free flaps advantages

• it’s a one stage procedure
• more comfortable position in post operative condition
• required period of immobilization is shorter
• provides option for single stage reconstruction

Disadvantages

• technically difficult
• longer duration of operation

• Depending on the location of the donor site

• local flaps
• flaps that rotate about a pivot

• rotation flap
• transposition flap
• Limberg flap → rhomboid defects with 60 and 120 angle
• Dufourmental flap → as for limberg except that it’s
• constructed for any rhomboid defect of any angle
• Bilobed flaps has primary and secondary flaps
• Interpolation flap

• Advancement flaps - moves forward into defect, no rotation or lat. movement

• single pedicled advancement flap
• bipedicled advancenent flap
• Y - V advancement / V -Y advancement flap
• crescentric advancement flap

Distant flaps

• Methods of transfer to primary defect:

• direct flap transfer

• by bringing primary defect near the flap e.g transfer of groin flap over hand defect
• bringing both flap and defect near each other e.g cross leg flap
• indirect flap transfer
• by wrist carrier
• by migration waltzing, caterpillar method and tumbling

Indications

• To resurface avascular recipient beds

• Bare bone, bare cartilage, bare tendon
• chronic wounds with extensive fibrosis
• irradiated beds

• Exposed implants or exposed joints

• To reconstruct full thickness defects of cheeks, ears, eyelids, lips and nose

• For providing durable cover over bony prominences and pressure points.

• For areas that may require secondary surgical procedure

Pathophysiology of flap

• Liu et al demonstrated

• Between 0- 24hours decrease blood supply, congestion and oedema , dilation of arterioles and capillaries

• Between 1 -3days increase no. and quantity of anastomoses b/w flap and recipient bed, increase number of small vessels in pedicle.

• In 3- 7days re orientation of vessels along the long axis of the flap, anastomoses of days 1 - 3 now functionally significant.

• After 1 week circulation is well established b/w the flap and recipient bed, pulsatile blood flow approaches pre op level.

• After 2 weeks continuous maturation of anastomoses b/w the flap and recipient site.

• After 3 weeks flap achieves 90% of its final circulation, with fully developed vascular connections. Flap for inset is divided and inserted

• After 4 weeks vessels achieve definitive sizes

• To provide sensation example neurovascular island flap[ with digital vessels and nerves] transferred from ulnar side of ring finger to the anaesthetic thumb

• For cosmetic reasons example local flaps over face

Disadvantages

• usually bulky, carry hairs to non hairy areas, leave scars over donor, multiple operation required.

Uses of flaps

• Use the nemonics

• F = filling of defects, restoration of function
• L = lining → provision of lining for flaps, mucosal restoration
• A = aesthetic, to achieve colour or contour match
• P = perfusion, used for poorly vascularised bed
• S = sensation, structural support , example sensory supply as in neurovascular flap, vascularised fibular graft for bone gap

• Motor function = to restore motor function example muscle tendon transfer

• Sensory function = to restore sensation example neurocutaneous flap

Methods of improving flap viability

• Preoperative Planning, theatre set up. Patient selection and optimization

• Preanastomosis Delay, flap hypothermia[ reduce metabolic rate ], short ischaemic time, anaesthesia input

• Postanastomosis Patient keep warm, well hydrated, pain free, Leeches Drugs steriods , aspirin, dextran , heparin

Methods of flap monitoring

• Clinical examination

• Ultrasound doppler

• Laser doppler

• Thermocouple probes

• Photoplethysmography

• Transcutaneous oxygen monitoring 

• PH monitoring

• Intravenous fluorescein

• Near infrared spectroscopy

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