Lower third leg defects

Anurag PandeyModerator : Dr Deepak Nanda

Anatomy

Blood Supply of Bones

Compartments of leg

Muscles of the Leg and Ankle

• Anterior Compartment– Borders

• Lateral Shaft of Tibia• Medial Shaft of Fibula• Interosseous membrane

Anterior Compartment

– Structures• Tibialis Anterior• Extensor Hallucis

Longus• Extensor Digitorum

Longus• Peroneus Tertius• Deep Peroneal Nerve• Anterior Tibial Artery• Anterior Tibial Vein

Lateral Compartment

– Borders• Lateral Fibula• Intermuscular fascia

between anterior compartment and posterior compartment

Lateral Compartment• Arterial supply to

the lateral compartment is via perforating branches of the anterior & posterior tibial arteries proximally and the fibular artery perforators distally.

Lateral Compartment

• Structures• Peroneus Longus• Peroneus Brevis• Superficial Peroneal

Nerve• Peroneal Artery• Superior and Inferior

Peroneal Retinaculum

Superficial Posterior Compartment

– Borders• Deep posterior

compartment• Fascia

Superficial Posterior Compartment

– Structures• Soleus• Gastrocnemius• Plantaris• Tibial Nerve• Posterior Tibial

Artery

Deep posterior compartment

• Borders– Interosseus

Membrane– Posterior Tibia– Posterolateral Fibula– Superficial Posterior

Compartment

Deep posterior compartment

• Structures – Tibialis Posterior– Flexor Digitorum

Longus– Flexor Hallucis

Longus– Tibial Nerve– Posterior Tibial

Artery

Causes of Defects

• Trauma• Tumor Resection• Vascular diseases – e.g. varicose veins• Infection• Others - Burns Trophic ulcers

Classification of Open FracturesGustilo 1984• Type I Open Fracture with a wound <1cm• Type II Open Fracture with a wound <1cm• Type III Open Fracture with extensive softtissue damage• IIIA Type III with adequate soft tissuecoverage• IIIB III with soft tissue loss with periostealstripping and bone exposure• IIIC III with arterial injury requiring repair

Other Scoring systems

• Mangled Extremity Syndrome Index• Mangled Extremity Severity Score• Predictive Salvage Index• Limb Salvage Index• Largely complex and not accurately

predictive(Bonanni et al 1993)

Historical Perspective

• Amputation: ancient technique‐Hippocrates (400BC)• Desault (1744‐1795): debridement oftraumatic wounds• Ollier (1825‐1900): POP immobilisation• WW1: Closed Plaster technique (Orr)• Spanish Civil War: Trueta‐– radical debridement before casting• WW2: Same techniques but better antisepsis/antibiotics• 1960’s: Advent of flap transfer• 1970’s: Microvascular techniques refined

Injury Recognition

• May be obvious, but degree of tissue damagecan easily be underestimated• Be aware of closed degloving or crush injury(either from trauma or immobilisation)• Look for signs of vessel and nerve injury• Involve orthopaedic and plastic surgeonearly

Treatment Plan

• Consideration of other injuries• Prevent contamination of wounds by hospitalorganisms (photo and cover)• Initial wound debridement and fracturestabilisation within 6 hrs• Definitive wound coverage within 5 days– NB consideration oftreatment location and timing

Types of fixation

Internal fixation– May be associated with better rates of malunion and non

union– May be more technically challenging– May not preserve endosteal blood supply,– Plates may compromise periosteum furtherExternal fixateurs– Fewer bone infections– Easier to apply– Associated with rates of high non/malunion– Can get in the way of micro team– Avoids extensive periosteal dissection

Timing of Soft Tissue Coverage• Balance between adequate debridement anddevelopment of infection– Infection usually hospital acquired organisms• Several studies addressing timing of woundclosure :Godina (1986)/ Gopal (2000)/ LEAPstudy group (2000)• Generally accepted: 3‐7 days is optimal, ie at2nd look operation

Problems in coverage of lower 1/3 of leg

• Paucity of skin and soft tissue as the leg is narrow as it comes down

• Subcutaneous placement of bone• Most extrinsic flexors and extensors

become tendinous• Little muscle available for transfer• Sacrifice of donor muscle may impair

locomotor function

Reconstructive Techniques

• Secondary Intention• Direct Closure• Skin Graft• Local Flap• Regional Flap• Distant Flap• Free Flap• Tissue Expansion

Skin grafts

• Technically simple• Can cover large soft tissue defects• Need appropriate wound bed– no bare bone, open joints or tendons devoid of

paratenon• Infected wounds?• Thin, non‐durable skin cover• Difficult to re-operate through

Flap Coverage

• Flap : tissue transferred or transplanted with intact circulation• Skin only• fascia + skin• Muscle• muscle + skin

• Local• Distant• free flaps

Loco regional Flaps

• Fasciocutaneous flaps Proximally based Distally based De epithelised turnover flaps• Muscle Flaps Distally based EDL Tibialis anterior (for proximal wounds) Peronius brevis • Island flaps Sural flap (distally based) Saphenous flap• Flaps based on perforator• Propeller flap

Distant FlapsFasciocutaneous flap crossleg flapFreeflaps • Free muscle flaps gracilis free flap rectus abdominis flap latissimus dorsi flap• Free fasciocutaneous flap lateral arm flap parascapular flap / scapular flap radial forearm flap

Local fasciocutaneous Flaps• Can be proximally or distally based• Based on septocutaneous perforators from ant. Tibial,

post. Tibial and peroneal arteries• These are possible only when the surrounding skin is

good • Degloving of the surrounding skin reduces the reliability

of these flaps• Perforator condition should be noted with a Doppler if

possible

• Medial perforators- From post. Tibial a. pierce fascia in 4 regions- b/w 4-6 cm, 9-12 cm, 17-19 cm and 22-24 cm from medial malleolus• Posterolateral perforators- from peroneal a. Cluster at proximal and distal end of fibula• Anterolateral perforators- from ant. Tibial a. Perforate fascia just lateral to tibia Cluster proximally b/w tibialis ant. & EDL and distally b/w EDL & peroneus brevis

Local fasciocutaneous Flaps….Transposition flap

‘V-Y’ advancement flap

• Takes advantage of the mobility of the skin once the fascia is fully incised

• Based on one or more perforators

Sural Neurocutaneous

Island Flap

Distally based superficial sural artery flap

• Described by Hasegawa• Very widely used in various forms – pedicled, islanded,

adipofascial• Can reach upto heel and proximal foot• Delay is necessary in case longer flaps are required i.e.

going on to the upper third of the leg

Drawing of the procedure

Saphanous neurocutaneous

island flap

Drawing of the procedure

Free flaps

• Requires microsurgical expertise• A variety of of flaps can be used according

to one's preference• Gracilis is used in smaller defects

Free Latissimus Dorsi Flap

Cross leg flaps

• In case of single vessel limbs In case where the donor vessels are not suitable for free tissue transferIpsilateral flaps are not availableWhen other bridges have been burnt

Propeller flaps Emerging concept

Isolation of pedicle helps 180 degree rotation of the flapDissection around the pedicle may be facilitated by the use of microscope

Scapula Free Flap

Scapular/Parascapular Free Flap

• Triangular space• May include bone• Venous Supply– Vena commitantes• Arterial supply– Circumflex scapular

Scapular/Parascapular Free Flap

• Advantages– Large skin paddle– Easy to harvest– Low donor sitemorbidity (closesprimarily)– Availability for

bone

• Disadvantages– Thick skin– Difficult positioning

Lateral Arm Free Flap• Venous supply– Vena

commitantes in spiral groove of

humerus• Arterial supply– Posterior radial

collateral artery from profunda brachii artery

Lateral Arm Free Flap• Advantages– Low donor sitemorbidity (verticalscar)– Easy positioning– Potential for sensoryinnervation via posterior

cutaneous nerve

• Disadvantages– Short and smaller caliber artery(maximum 14 cm)– Longer dissectionthan RFFF– Thickersubcutaneous tissue

Rectus Abdominus Free Flap• Arterial supplybased on deepinferior epigastricartery• Venous supply formvena commitantesjoining external iliacvein

Rectus Abdominus Free Flap• Advantages– Easy positioning andharvest– Long and largecaliber vessel– Donor site closedprimarily– Large flap obtained– Anterior rectussheath durable

• Disadvantages– Often bulky– No sensation potential– Potential for hernia formation ifdissection belowarcuate line

Latissimus Dorsi Free Flap• Arterial supply based on thoracodorsal artery• Venous drainage from thoracodorsal vein• Motor nerve innervation potential with thoracodorsal• nerve

Latissimus Dorsi Free FlapAdvantages– Large flap with longpedicle– Possibility for“axillary megaflap”– Low donor sitemorbidity– Possibility of musclereinnervation viathoracodorsal nerve

Disadvantages– Difficult positioningand two teamharvest– Postoperativeseroma formation– Bulky flap

Radial Forearm Free Flap• Venous Source– Deep venous commitantes

and/or cephalic vein

• Arterial source– Radial artery

Radial Forearm Free FlapAdvantages– Thin skin with long, large

pedicle– Easy positioning– Potential for sensate flap– Potential for unusual shapes– Potential for vascularized bone– Ease of preoperative evaluation

Disadvantages– Loss of hand– Poorly aesthetic donorsite– Requires skin graft– Potential for pathologicfractures– Loss of hand function

Lateral Thigh Free Flap• Arterial supply is from third perforator of profunda femoris artery• Venous output from associated vena commitantes

Lateral Thigh Free Flap• Advantages– Large amount of thin, hairless skin– Low donor site morbidity (primary closure)– Easy positioning– Sensation potential with lateral femoral cutaneous nerve

Disadvantages– Difficult dissection– Small, variablepedicle

Fibula Free FlapArterial supply basedon peroneal artery• Venous supply isaccompanying venacommitantes• Aberrations in bloodsupply (10%)• Peripheral vasculardisease

Fibula Free FlapAdvantages– Longest andstrongest bone stock– Low donor sitemorbidity– Easy positioning– Excellent periostealblood supply(contouring)– Supportosseointegratedimplants

Disadvantages– High incidence ofperipheral vasculardisease– Small cutaneouspaddle– Decreased anklestrength and toeflexion– Small risk chronicankle pain

-allows for transfer of bone, soft tissue and skin in a one-stage procedure using only one donor site

-fibula flap allows the most bone (up to 25-30cm) vs. 10-15 for the other bone flaps

-blood supply to fibula is both intraosseous and segmental, therefore, osteotomies can be made

-fibula allows for a skin paddle up to 25cm in length and 5cm in width

Advantages

A: scapula B: iliac crest C: radius D: fibula