Reconstructive Flaps

1. Overview

Definition

A flap is a unit of tissue that is transferred from a donor site to a recipient site while maintaining its own blood supply. This fundamental characteristic distinguishes flaps from grafts, which rely entirely on the vascularity of the recipient bed for survival (revascularisation).

The term "flap" originates from the Dutch word flappe, meaning something that hangs loose, attached only by one side. In modern surgery, it represents the highest rung of the traditional reconstructive ladder, offering solutions for complex defects that cannot be managed by simpler means.

Clinical Importance

Flaps are the cornerstone of reconstructive surgery, allowing for the restoration of form and function in complex defects where simpler methods (primary closure, skin grafting) are inadequate or contraindicated. They are essential for:

• Coverage of Avascular Structures: Exposed bone (without periosteum), tendon (without paratenon), nerve, cartilage, or synthetic implants (e.g., breast implants, orthopaedic hardware).
• Restoration of Bulk and Contour: Essential in breast reconstruction, glossectomy defects, and pressure sore management.
• Functional Restoration: Transferring functional muscle for facial reanimation (e.g., gracilis) or extremity motor function (e.g., free gracilis for Volkmann's contracture).
• Specialised Tissue Requirements: Providing sensate skin (e.g., glabrous skin for finger tips), vascularised bone (e.g., mandible or long bone defects), or composite tissues.

The evolution of flap surgery—from random pattern skin flaps to axial pattern flaps, and ultimately to free tissue transfer—represents one of the most significant advancements in modern surgery.

Key Clinical Message

Successful flap surgery requires a detailed understanding of vascular anatomy (angiosomes), careful patient selection, meticulous surgical technique, and rigorous post-operative monitoring. The "Reconstructive Ladder" has evolved into the "Reconstructive Elevator," emphasising the selection of the best reconstruction for the patient, rather than simply the simplest.

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2. Epidemiology and Indications

Epidemiology of Flap Use

Free tissue transfer has become increasingly common since the advent of microsurgery in the 1970s. Contemporary series report:

• Success Rates: 95-98% for free flaps in experienced centres. [1]
• Breast Reconstruction: Approximately 40% of mastectomy patients undergo reconstruction, with autologous tissue comprising 30-40% of these cases. [2]
• Lower Limb Trauma: BOAST 4 guidelines recommend flap coverage within 72 hours for Gustilo IIIB fractures, reducing infection rates from 40% to less than 10%. [3]
• Head & Neck Reconstruction: Free flaps are now standard following major ablative surgery, with success rates exceeding 95%. [4]

Indications

Flaps are indicated when a defect cannot be closed primarily or with a skin graft. The decision to use a flap is often driven by the state of the wound bed and the functional requirements of the recipient site.

Absolute Indications

1. Poor Vascularity of the Bed: A graft requires a vascular bed to survive (plasmatic imbibition → inosculation). Exposed bone cortex, tendon, cartilage, and prosthetic material are avascular and will not support a graft.
2. Vital Structure Protection: Major vessels or nerves exposed in a wound require robust, vascularised coverage to prevent desiccation and rupture/neuroma formation.
3. Restoration of Function: Where dynamic tissue is needed (e.g., blinking, smiling, grasping).
4. Dead Space Management: To fill cavities (e.g., pelvic exenteration, chronic osteomyelitis debridement) and prevent seroma/infection.

Relative Indications

1. Cosmesis: Flaps often provide better colour and texture match than grafts (e.g., forehead flap for nasal reconstruction).
2. Durability: Over bony prominences (e.g., ischium, sacrum, heel), flaps provide padding that withstands shear and pressure better than grafts.
3. Future Surgery: If a site requires secondary surgery (e.g., tendon repair/transfer later), a flap allows for re-elevation, whereas a graft does not.

Common Clinical Scenarios

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3. Anatomy & Physiology

Vascular Anatomy: The Angiosome Concept

The Angiosome Theory, described by Taylor and Palmer (1987), is the anatomical basis for all flap surgery. It revolutionised the understanding of blood supply, moving away from "random" concepts to defined vascular territories.

• Definition: The body is divided into ~40 three-dimensional composite blocks of tissue (skin, subcutaneous tissue, fascia, muscle, bone), each supplied by a specific source artery and drained by accompanying veins. [8]
• Vessels:
  • Source Arteries: Major segmental vessels (e.g., Deep Inferior Epigastric Artery).
  • Choke Vessels: Adjacent angiosomes are connected by "choke vessels" (reduced calibre vessels found in the subdermal plexus and muscles). These define the boundaries of the angiosome.
  • True Anastomoses: Direct connections without change in calibre (less common).
• Clinical Relevance:
  • A flap can safely include the primary angiosome (supplied by the pedicle).
  • It can typically capture the adjacent angiosome by relying on the opening of choke vessels.
  • Capturing a third angiosome (one removed from the source) is unreliable and usually leads to distal necrosis unless a "delay procedure" is performed.

Flap Physiology and Survival

Flaps rely on perfusion pressure to maintain viability. The critical factor is the pressure gradient between the arterial inflow and venous outflow.

1. Arterial Supply

• Delivers oxygen and nutrients.
• Critical Closing Pressure: If perfusion pressure falls below this (due to hypotension, compression, or vasospasm), capillaries collapse, and flow ceases.

2. Venous Drainage

• Removes metabolic waste and CO2.
• Venous Insufficiency: This is the most common cause of early flap failure. Venous congestion increases hydrostatic pressure, leading to oedema. Oedema further compresses the capillary bed, creating a vicious cycle (compartment syndrome of the flap) that eventually stops arterial inflow.

3. Microcirculation

• Pre-capillary sphincters and A-V shunts regulate flow.
• Sympathetic Tone: Flaps are initially sympathectomised (nerves cut). This leads to vasodilation. However, vessel walls are hypersensitive to circulating catecholamines (denervation supersensitivity). Cold and pain can cause severe spasm.

Ischaemia-Reperfusion Injury (IRI)

When a free flap is harvested, it undergoes a period of primary warm ischaemia. Upon revascularisation, paradoxical tissue injury can occur.

• Mechanism:
  • Ischaemia: Depletion of ATP, accumulation of hypoxanthine.
  • Reperfusion: Oxygen influx converts hypoxanthine to xanthine via Xanthine Oxidase, generating Reactive Oxygen Species (ROS) (Superoxide, Hydrogen Peroxide).
  • Consequences: Endothelial damage, neutrophil adhesion/activation, microvascular plugging ("No-Reflow Phenomenon"), and tissue necrosis.
• Clinical Implication: Minimising ischaemia time is crucial. "Safe" warm ischaemia times vary by tissue:
  • Skin/Fascia: 4-6 hours.
  • Muscle: 2-3 hours (more sensitive).
  • Bone: > 24 hours (highly tolerant).

Exam Detail: The Delay Phenomenon Surgical delay involves partially raising a flap (incising margins or dividing select vessels) and leaving it in situ for a period (usually 1-3 weeks) before final transfer.

• Mechanism:
  1. Sympathectomy: Immediate release of catecholamines leads to vasodilation.
  2. Vascular Reorganisation: Choke vessels dilate and reorient longitudinally, becoming true channels.
  3. Ischaemic Conditioning: Tissue becomes more tolerant to hypoxia (HIF-1alpha upregulation, VEGF release). [9]
• Indication: To increase the safe surface area of a flap (e.g., extending a TRAM flap across the midline, or a random pattern flap beyond 1:1 ratio).

Vascular Territories and Perfusion Zones

Understanding the zones of perfusion within a flap is critical for surgical planning:

• Zone I: Directly over the vascular pedicle - most reliable perfusion
• Zone II: Adjacent to Zone I, supplied via intramuscular or fascial plexus
• Zone III: Contralateral side, supplied via choke vessels - less reliable
• Zone IV: Most distant from pedicle - highest risk of necrosis

This concept is particularly important in:

• TRAM/DIEP flaps: Hartrampf zones determine which abdominal tissue is included
• Pedicled flaps: Arc of rotation affects distal perfusion
• Perforator flaps: Multiple perforators may be needed to capture larger territories

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4. Classification of Flaps

Flaps are classified by blood supply, tissue composition, and method of transfer.

A. Classification by Blood Supply

This is the most critical classification for understanding viability.

1. Random Pattern Flaps

• Blood Supply: Dermal and subdermal plexus. No named vessel. Relies on pressure gradient from base to tip.
• Limitations: Limited length-to-width ratio (traditionally 1:1 in lower limb, 2:1 in face/scalp due to better vascularity).
• Examples: Local rotation, transposition (Z-plasty, Limberg), advancement flaps.

2. Axial Pattern Flaps

• Blood Supply: A named direct cutaneous artery running along the longitudinal axis of the flap.
• Advantages: Much longer flaps can be raised safely, irrespective of width, as long as the vessel is included.
• Examples:
  • Forehead Flap: Supratrochlear artery.
  • Groin Flap: Superficial Circumflex Iliac Artery (SCIA).
  • Deltopectoral Flap: Internal Mammary Artery Perforators (IMAP).

3. Perforator Flaps

• Definition: A flap supplied by a perforating vessel that passes through muscle or intermuscular septa to supply the skin/fat, allowing the muscle to be spared.
• History: Koshima and Soeda (1989) described the Inferior Epigastric Artery skin flap without rectus muscle, birthing the "perforator era".
• Nomenclature: Named after the source artery (e.g., DIEP) or the muscle perforated (e.g., MS-TRAM).
• Examples: DIEP, ALT, TAP, SGAP (Superior Gluteal Artery Perforator).

B. Classification by Tissue Composition

C. Classification by Muscle Flap Blood Supply (Mathes & Nahai, 1981) [10]

Essential for FRCS (Plast). Candidates must know this classification and examples.

Mnemonic: Ten Gracile Glutes Sat Low (Tensor, Gracilis, Gluteus, Sartorius, Latissimus)

D. Classification of Fasciocutaneous Flaps (Cormack & Lamberty, 1984) [11]

E. Classification by Method of Transfer

1. Local Flaps

• Definition: Moved from adjacent tissue to close defect
• Arc of rotation: Limited to immediate vicinity
• Advantages: Same aesthetic unit, excellent match
• Types:
  • Advancement: V-Y, single/bipedicled advancement
  • Rotation: Curvilinear incision, rotating around pivot point
  • Transposition: Z-plasty, Limberg (rhomboid), bilobed
• Examples: Limberg flap for sacral defect, V-Y advancement for fingertip

2. Regional/Pedicled Flaps

• Definition: Tissue moved from nearby region but maintains original blood supply
• Arc of rotation: Determined by pedicle length and pivot point
• Examples:
  • Pectoralis major for head/neck
  • Latissimus dorsi for chest wall
  • Gastrocnemius for proximal third tibia
  • Soleus for middle third tibia

3. Distant Pedicled Flaps

• Definition: Tissue transferred via multi-stage procedure
• Historical significance: Largely replaced by free flaps
• Examples: Cross-leg flap, tube pedicle flaps (Gillies)
• Modern use: Rare, mainly in resource-limited settings

4. Free Flaps

• Definition: Complete detachment with microsurgical anastomosis
• Advantages: Greatest versatility, any donor to any recipient
• Requirements: Microsurgical expertise, appropriate vessels
• Examples: DIEP, ALT, fibula, radial forearm

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5. Reconstructive Strategy

The Reconstructive Ladder (Traditional)

A hierarchical approach starting from the simplest method.

1. Healing by Secondary Intention: Suitable for small wounds in concave areas.
2. Primary Closure: Direct suture.
3. Skin Graft (Split/Full): Needs vascular bed.
4. Local Flap: Random pattern.
5. Regional Flap: Pedicled axial/myocutaneous.
6. Free Flap: Microvascular transfer.

The Reconstructive Elevator (Modern)

This concept argues for skipping rungs of the ladder to select the optimal reconstruction for form and function.

• Example: A young patient with a large traumatic heel defect. A skin graft or local flap provides poor durability and sensation. A free flap (e.g., ALT or radial forearm) is the "elevator" choice—more complex but provides superior long-term functional outcome with durable skin and padding.

Pre-Operative Assessment

1. Patient Optimisation

• Smoking: Major risk factor. Nicotine causes vasoconstriction; CO reduces oxygen carrying capacity. Cessation 4 weeks pre-op is ideal.
• Diabetes: Microangiopathy affects wound healing. HbA1c less than 7% preferred.
• Obesity: Increases risk of dehiscence and seroma. BMI > 35 increases complications.
• Coagulopathy: Assess personal/family history of DVT/PE.
• Nutrition: Albumin > 3.0 g/dL, adequate protein intake (1.5-2g/kg/day)
• Medications: Review anticoagulants, immunosuppressants, steroids
• Age: Elderly patients tolerate long procedures less well but age alone not contraindication

2. Defect Analysis: "What is missing?"

• Tissue: Skin, mucosa, muscle, bone, nerve?
• Dimensions: Size and depth - affects flap choice
• Condition: Infection, radiation, contamination?
• Location: Critical structures, aesthetic units
• Timing: Acute vs chronic, immediate vs delayed

3. Vessel Assessment

• Handheld Doppler: To mark perforators, assess recipient vessels
• CT Angiogram (CTA): Gold standard for DIEP, ALT, and Fibula planning. Maps perforator course and vessel patency (e.g., run-off to foot in fibula harvest).
• Allen's Test: Mandatory for Radial Forearm harvest to ensure ulnar artery dominance.
• Recipient vessels: Assessment of caliber, proximity, prior surgery/radiation
• Vein mapping: Especially for limb salvage with venous disease

4. Timing Considerations

• Immediate vs Delayed: Oncologic considerations in cancer reconstruction
• Early vs Late: Godina's principle of less than 72 hours for trauma [12]
• Single vs Staged: Patient factors, operative time constraints
• Emergency vs elective: Trauma vs planned reconstruction

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6. Intra-Operative Principles

Flap Raising Techniques

• Design: "Measure twice, cut once." Always plan for a slightly larger flap to account for elasticity/shrinkage.
• Template: Use sterile paper/plastic to create template of defect
• Dissection:
  • Atraumatic "no-touch" technique.
  • Use skin hooks rather than forceps on skin edges.
  • Maintain perfect haemostasis to visualise planes.
  • Sharp dissection preferred for precision
• Perforator Dissection:
  • Identify the perforator emerging from fascia.
  • Carefully dissect through muscle (intramuscular dissection) ligating side branches with clips or bipolar.
  • Preserve motor nerves to the muscle if possible.
  • Use loupe magnification or microscope for fine dissection
• Pedicle Handling:
  • Avoid torsion, tension, or kinking.
  • Use Papaverine or Lignocaine topically on vessels to prevent vasospasm.
  • Hydrodissection of the adventitia can help clear the vessel ends for anastomosis.
  • Keep pedicle moist with warm saline-soaked gauze

Microvascular Anastomosis (For Free Flaps)

• Setup:
  • Operating microscope with high magnification (10-20x)
  • Microsurgical instruments (jeweler's forceps, needle holders)
  • Bipolar coagulation for hemostasis
• Vessel Prep:
  • Trim adventitia from vessel ends ("circumcision") to prevent it falling into lumen
  • Irrigate lumen with heparinized saline
  • Dilate vessels gently with dilators
• Suture: 8-0, 9-0, or 10-0 Nylon on non-cutting needle
• Technique:
  • End-to-End: Standard - most common
  • End-to-Side: Used when preserving distal flow in the recipient vessel is critical (e.g., single vessel leg)
  • Suturing: Interrupted sutures (standard, allows adjustment) or continuous (faster)
  • Pattern: Usually 8-12 sutures for artery, 10-16 for vein depending on size
• Venous Coupler Device:
  • Polyethylene ring with stainless steel pins
  • Advantages: Faster (saves 10-15 min), keeps lumen distinct (intima-to-intima contact), structurally rigid preventing collapse [13]
  • Disadvantages: Size limitations, cost, learning curve

Intra-operative Assessment

• Clinical Assessment: Color, capillary refill, turgor, bleeding from flap edge
• Handheld Doppler: Audible arterial (triphasic) and venous (continuous) signals
• Implantable Doppler: Cook-Swartz probe placed on vein - gives continuous monitoring
• Fluorescence Angiography: Indocyanine green (ICG) to assess perfusion in real-time
• Laser Doppler: Continuous tissue perfusion monitoring

Special Techniques

Supercharging and Superdrainage

• Supercharging: Additional arterial inflow anastomosis to improve perfusion
  • Indications: Large flaps, marginal perforators, zone IV tissue inclusion
• Superdrainage: Additional venous outflow to prevent congestion
  • Indications: Venous congestion risk, superficial system dominant
• Evidence: Increases flap reliability but adds operative time and complexity

Flow-Through Flaps

• Concept: Flap placed in series with main vessel to preserve distal flow
• Applications: Lower limb reconstruction in single-vessel legs
• Technique: Proximal and distal arterial anastomoses - vessels "flow through" flap

Chimeric Flaps

• Definition: Multiple tissue components from same source vessel
• Example: ALT skin + vastus lateralis muscle both on descending LCFA
• Advantage: Customizable reconstruction with single pedicle

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7. Post-Operative Management

Flap Monitoring Protocol

Early detection of vascular compromise is critical. Time is Tissue. Salvage is most successful if performed within 6 hours of onset.

Monitoring Schedule

• 0-24 Hours: Every 30-60 minutes (critical period)
• 24-48 Hours: Every 1-2 hours
• Day 3-5: Every 4 hours
• Day 5-7: Every 6-8 hours (if stable)
• After Day 7: Routine wound checks

Medical Management

Anticoagulation

Controversial topic with variable practice.

• Standard Protocol:
  • Aspirin 75mg-300mg daily (started pre-op or immediately post-op)
  • LMWH (prophylactic dose) for DVT prophylaxis
• High Risk (Trauma/Thrombophilia/Redo surgery):
  • Therapeutic Heparin infusion
  • Dextran-40 (rheological agent, less common now)
• Evidence: Meta-analyses show aspirin may reduce thrombosis without increasing bleeding [15]
• Duration: Typically continue aspirin for 2-4 weeks

General Management

• Fluid Balance:
  • Aim for hyperdynamic circulation
  • Avoid hypotension (MAP > 65mmHg)
  • Vasopressors (Noradrenaline) safe if volume replete
• Environment:
  • Warm room (> 22°C) to prevent peripheral vasoconstriction
  • Bair Hugger to patient
  • Avoid cold exposure
• Pain Management:
  • Adequate analgesia prevents catecholamine release and vasospasm
  • Multimodal approach
  • Avoid excessive opioids (nausea, ileus)
• Positioning:
  • Head elevation for head/neck flaps (30 degrees)
  • Limb positioning to avoid pedicle kinking
  • Pressure relief for flap and donor site

Enhanced Recovery After Surgery (ERAS)

Modern flap surgery incorporates ERAS principles:

• Pre-operative counseling and optimization
• Avoid prolonged fasting
• Multimodal analgesia (reducing opioids)
• Early mobilization protocols
• Standardized fluid management
• Reduced drain use where safe
• Early discharge pathways for selected cases
• Improved outcomes and reduced length of stay

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8. Complications & Salvage

Vascular Compromise (The "Red Flag")

• Incidence: 5-10% of free flaps
• Salvage Rate: 50-70% if taken back to theatre promptly
• Timing: Most failures occur in first 48-72 hours (85% in first 48h)
• Golden period: Within 6 hours of onset gives best salvage rates

1. Venous Congestion (Most Common - 60-70% of failures)

• Pathophysiology: Outflow obstruction → Hydrostatic pressure ↑ → Oedema → Capillary collapse
• Signs:
  • Blue/purple flap
  • Rapid capillary refill (less than 1 second)
  • Dark blood on needle prick
  • Swollen/tense
  • Bleeding from suture lines
• Causes:
  • Thrombus at venous anastomosis (most common)
  • Kinking of pedicle (check head/neck position!)
  • External compression (tight dressing/haematoma)
  • Inadequate venous drainage (small veins, single vein)
• Management:
  • Immediate bedside:
    • Release dressings/sutures
    • Elevate limb/head
    • Check alignment
    • Remove hematoma if present
  • Surgical (Urgent):
    • Return to theatre immediately
    • Thrombectomy (Fogarty catheter or milking)
    • Revision of anastomosis
    • Consider additional venous anastomosis (superdrainage)
  • Leech Therapy (Hirudo medicinalis):
    • Used for venous congestion where surgical revision fails or is not possible
    • Indications: Distal tip congestion, replantation, diffuse congestion
    • Mechanism: Inject Hirudin (anticoagulant) and hyaluronidase. They actively suck blood (5-10ml) and promote oozing for hours
    • Protocol: 2-3 leeches every 4-6 hours, continue for 3-7 days until venous system re-establishes
    • Prophylaxis: Aeromonas hydrophila is a gut commensal of the leech. Ciprofloxacin 500mg BD or Co-trimoxazole is MANDATORY to prevent serious infection [16]
    • Monitoring: Check Hb daily (blood loss can be significant), transfuse if needed

2. Arterial Insufficiency (30-40% of failures)

• Signs:
  • Pale, white flap
  • Cool to touch
  • Empty/flaccid appearance
  • No capillary refill (> 5 seconds)
  • No bleeding on needle prick
• Causes:
  • Thrombus (platelet aggregation at anastomosis)
  • Vasospasm
  • Kinking of arterial pedicle
  • Systemic hypotension
  • Intimal dissection/flap
• Management:
  • Urgent re-exploration
  • Check anastomosis patency
  • If thrombus: thrombectomy + revision of anastomosis
  • If spasm: warm irrigation, papaverine, gentle dilation
  • Intra-arterial TPA (tissue plasminogen activator) for distal micro-emboli ("rescue therapy")
  • Ensure adequate perfusion pressure (MAP > 65)

3. Mixed/Progressive Failure

• Presentation: Initial arterial insufficiency progressing to venous congestion
• Causes:
  • Haematoma compressing entire pedicle
  • Systemic hypotension
  • Severe vasospasm affecting inflow and outflow
• Management: Address underlying cause, urgent exploration if no rapid improvement

Other Complications

Partial Necrosis

• Incidence: 5-15% of flaps
• Location: Usually distal tip (furthest from pedicle), zone IV tissue
• Causes:
  • Inadequate perfusion to distal zones
  • Delay phenomenon not performed when needed
  • Choke vessel failure
• Management:
  • Conservative observation if small area (less than 10% flap)
  • Debride when clearly demarcated (7-14 days)
  • Skin graft or small local flap for coverage
  • Serial debridement may be needed

Haematoma/Seroma

• Incidence: 10-20% overall
• Risk factors:
  • Large dead space
  • Inadequate drainage
  • Anticoagulation
  • Obesity
• Prevention:
  • Quilting sutures (particularly for LD, DIEP)
  • Adequate drainage
  • Compression garments
• Management:
  • Aspiration if small and not expanding
  • Evacuation if large or compromising flap
  • Prolonged drainage (drains may stay 2-4 weeks)

Infection

• Incidence: 3-10%
• Risk factors:
  • Trauma, contamination
  • Diabetes, immunosuppression
  • Smoking
  • Prolonged operative time
• Presentation:
  • Early (less than 1 week): May compromise flap vascularity, systemic sepsis
  • Late (> 1 week): Chronic infection, sinus formation, cellulitis
• Management:
  • Antibiotics (culture-directed)
  • Debridement if deep collection or abscess
  • May require flap removal if uncontrolled sepsis

Fat Necrosis

• Common in: DIEP, TRAM, SGAP flaps (adipose-rich flaps)
• Incidence: 10-20% of abdominal flaps
• Presentation:
  • Firm lumps/nodules
  • Oil cysts
  • May be tender
• Imaging: May mimic recurrence on mammography (important in breast reconstruction)
• Management:
  • Usually conservative (most resolve)
  • Ultrasound or MRI to differentiate from recurrence
  • Excision if symptomatic or diagnostic uncertainty

Donor Site Morbidity

Abdominal Donor Sites (DIEP/TRAM)

• Hernia/Bulge:
  • DIEP: 1-5%
  • TRAM: 10-20%
  • Risk factors: obesity, poor fascia, mesh not used
• Prevention:
  • Meticulous fascial closure
  • Mesh reinforcement if large defect
  • Component separation for wide defects
• Seroma: Common (20-30%), usually resolves with drainage
• Wound dehiscence: 2-5%, higher in obese/diabetic patients

Fibula Donor Site

• Ankle instability:
  • Preserve 6cm distal fibula to maintain ankle mortise
  • Rare if this preserved
• Peroneal nerve injury:
  • Protect common peroneal nerve proximally
  • Foot drop in 1-2% if nerve damaged
• Compartment syndrome:
  • Monitor postoperatively
  • Rare but serious complication
• Long-term:
  • Generally well tolerated
  • Minimal functional deficit in most patients
  • May have mild ankle stiffness

Radial Forearm Donor Site

• Aesthetic:
  • Visible scar on forearm
  • Requires skin graft (poor cosmesis)
  • Patient counseling essential
• Sensory loss:
  • Superficial radial nerve territory (dorsum of thumb/1st web)
  • Usually well tolerated
• Radial artery sacrifice:
  • Ensure adequate ulnar perfusion (Allen test mandatory)
  • Cold intolerance in 10-15%
  • Rarely causes hand ischemia if Allen test normal
• Tendon exposure:
  • Preserve paratenon for graft take
  • If exposed, consider local flap coverage
• Radius fracture:
  • Rare (less than 1%) if periosteum preserved
  • Higher risk if bone harvest performed

ALT Donor Site

• Minimal morbidity:
  • Can usually close primarily if less than 8-10cm width
  • Excellent cosmesis (hidden by clothing)
• Sensory loss:
  • Lateral femoral cutaneous nerve territory
  • Usually well tolerated
• Seroma:
  • Quilting sutures reduce incidence
  • Drain until less than 30ml/day
• Contour deformity:
  • Usually acceptable
  • May have slight contour irregularity

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9. Specific Flaps (High Yield for Examinations)

1. Radial Forearm Free Flap (RFFF)

• Type: Fasciocutaneous (Cormack & Lamberty Type B - septocutaneous)
• Vessel: Radial artery and venae comitantes (usually 2 veins)
• Anatomy:
  • Flap centred over radial artery in distal forearm
  • Deep fascia included
  • Septum between brachioradialis and flexor carpi radialis
• Dimensions: Up to 10x20cm, pedicle length 12-15cm
• Utility:
  • "Workhorse" for head and neck (intra-oral lining) due to thinness, pliability, and long pedicle
  • Penis reconstruction (tube-in-tube, "Chang flap")
  • Thumb reconstruction
• Pearls:
  • Mandatory Allen's test pre-op (occlude radial artery, ensure pink hand from ulnar within 5 seconds)
  • Careful preservation of paratenon over flexor tendons to accept skin graft
  • Superficial branch of radial nerve is at risk (lies between brachioradialis and ECRL)
  • Can harvest palmaris longus tendon (if present - 15% absent)
  • Can be sensate (lateral/medial antebrachial cutaneous nerve)
• Pitfalls:
  • Radial artery sacrifice - abnormal Allen test is absolute contraindication
  • Visible donor site deformity
  • Radius fracture if osteocutaneous (rarely done now - replaced by fibula)

2. Anterolateral Thigh (ALT)

• Type: Fasciocutaneous or Musculocutaneous (Cormack & Lamberty Type C)
• Vessel: Descending branch of Lateral Circumflex Femoral Artery (LCFA), branch of profunda femoris
• Anatomy:
  • Septocutaneous (60-70%) or Musculocutaneous (30-40%) perforators
  • Usually found in midpoint of line between ASIS and superolateral patella
  • Perforator emerges through vastus lateralis muscle or lateral intermuscular septum
• Dimensions:
  • Very large flaps possible (up to 25x35cm)
  • Pedicle 8-12cm
  • Can include vastus lateralis muscle
• Utility:
  • "Universal flap"

• versatile for many defects
  • Can be thinned or taken with Vastus Lateralis muscle
  • Minimal donor morbidity (primary closure of thigh)
  • Head & neck, limb, trunk reconstruction

• Pearls:
  • "Chimera" flap possible (separate skin and muscle paddles on same source)
  • Can include tensor fascia lata, rectus femoris, vastus lateralis
  • Thinning procedures to reduce bulk for head/neck reconstruction (can thin to 5mm in distal flap)
  • Sensate flap possible (lateral femoral cutaneous nerve - but often sacrificed)
• Pitfalls:
  • Anatomical variation - perforators absent in 1-2%, may need to convert to TFL or AMT (anteromedial thigh)
  • Can be bulky in obese patients (requires thinning)

3. Deep Inferior Epigastric Perforator (DIEP)

• Type: Perforator (fasciocutaneous)
• Vessel: Deep Inferior Epigastric Artery (DIEA), branch of external iliac
• Anatomy:
  • Skin/fat of lower abdomen (TRAM flap territory without muscle)
  • Zone 1-4 (Hartrampf zones)
  • Perforators pass through rectus abdominis (intramuscular dissection required)
• Dimensions:
  • Entire lower abdominal tissue available
  • Pedicle 8-12cm
  • Can harvest up to 1500-2000g tissue
• Utility:
  • Gold standard for autologous breast reconstruction
  • Natural ptosis, sensation, aging
  • Spares rectus muscle (cf. TRAM)
• Pearls:
  • Zones of perfusion (Hartrampf/Holm zones):
    • Zone 1: Ipsilateral over pedicle (best)
    • Zone 2: Ipsilateral across midline (good)
    • Zone 3: Contralateral over opposite DIEA (fair - via choke vessels)
    • Zone 4: Contralateral lateral (poor - usually discarded or supercharged)
  • CT angiography pre-op to map perforators (medial vs lateral row)
  • Medial row perforators usually larger and more reliable
  • May need to include SIEV (superficial inferior epigastric vein) if superficial system dominant
  • Stacked DIEP (bilateral) for very large breasts or bilateral reconstruction
• Pitfalls:
  • Venous congestion if superficial system dominant (may need SIEV anastomosis)
  • Fat necrosis in 10-20% (usually zone 3/4)
  • Longer operative time than TRAM (perforator dissection adds 30-60 min)

4. Latissimus Dorsi (LD)

• Type: Myocutaneous (Mathes & Nahai Type V)
• Vessel: Thoracodorsal artery (branch of Subscapular artery from axillary)
• Anatomy:
  • Large flat muscle of back
  • Skin paddle overlying muscle, can extend to midline
  • Dominant pedicle enters 8-10cm from origin
  • Secondary segmental pedicles from lumbar/intercostal vessels
• Dimensions:
  • Muscle up to 20x40cm
  • Pedicle 8-10cm (very reliable)
  • Can transfer large volume
• Utility:
  • Pedicled: Breast reconstruction, chest wall coverage
  • Free: Lower limb, scalp, large defects
  • Large volume, robust blood supply
• Pearls:
  • Functional deficit is well tolerated (shoulder adduction/extension preserved by Teres Major/Pectoralis Major)
  • Seroma is very common (20-40% - quilting sutures reduce risk)
  • Can be split (separate thoracodorsal nerve branches for segmental function)
  • Extended LD includes skin to midline
  • Can be reversed (based on secondary pedicles) for paraplegia coverage
• Pitfalls:
  • Seroma formation (may need prolonged drainage 3-4 weeks)
  • Donor site visibility (especially in thin patients)

5. Free Fibula

• Type: Osteocutaneous (bone + soft tissue composite)
• Vessel: Peroneal artery and venae comitantes
• Anatomy:
  • Fibula bone (take middle third, leave 6cm proximal and distal for knee/ankle stability)
  • Skin paddle supplied by septocutaneous perforators via posterior crural septum
  • Flexor hallucis longus and peroneus muscles
• Dimensions:
  • Up to 25-26cm bone available
  • Skin paddle 10x20cm (less reliable than bone)
  • Pedicle 6-8cm
• Utility:
  • Long bone defects (> 6cm)
  • Mandible reconstruction (gold standard)
  • Allows dental implants (osseointegration)
  • Femur, tibia, humerus reconstruction
• Pearls:
  • Can perform multiple osteotomies to shape bone (for mandible curve) while maintaining periosteal blood supply
  • CTA pre-op mandatory to confirm three-vessel runoff to foot (need AT, PT, peroneal)
  • If peroneal dominant/only vessel to foot → contraindication
  • Skin paddle less reliable than bone (10-20% partial necrosis)
  • "Double-barrel" technique for increased height (fold fibula on itself)
• Pitfalls:
  • Foot drop (damage to common peroneal nerve proximally) - nerve runs around fibular neck
  • Compartment syndrome (monitor post-op)
  • Ankle instability if less than 6cm distal fibula preserved

6. Gracilis

• Type: Muscle (Mathes & Nahai Type II)
• Vessel: Ascending branch of Medial Circumflex Femoral Artery (MCFA), branch of profunda femoris
• Anatomy:
  • Long, thin muscle of medial thigh (adductor)
  • Pedicle enters 8-10cm from origin (proximal)
  • Minor pedicles distally
• Dimensions:
  • 20-25cm length
  • 4-6cm width
  • Pedicle 5-6cm
• Utility:
  • Pedicled: Perineal reconstruction, groin coverage, vaginal reconstruction
  • Free Functional: Facial reanimation (with obturator nerve branch for smile), Volkmann's contracture (functional muscle transfer)
  • Free Non-functional: Small/medium soft tissue defects
• Pearls:
  • "Disposable" muscle (adductor function preserved by adductor longus/magnus)
  • Proximal pedicle (allows wide rotation)
  • Obturator nerve enters with pedicle - functional muscle transfer possible (cross-face nerve graft for smile)
  • Minimal donor morbidity
  • Can be split for dual innervation
• Pitfalls:
  • Thin muscle may provide insufficient bulk for some defects
  • Limited muscle excursion (15-20% vs 30-40% for other muscles)

7. Pectoralis Major (Pedicled)

• Type: Myocutaneous (Mathes & Nahai Type V)
• Vessel:
  • Dominant: Pectoral branch of thoracoacromial artery
  • Secondary: Lateral thoracic artery, internal mammary perforators
• Anatomy: Large chest wall muscle with overlying skin paddle
• Utility:
  • Head and neck reconstruction (workhorse pedicled flap)
  • Sternal coverage (median sternotomy wounds)
  • Intrathoracic defects
• Advantages:
  • Reliable
  • Fast to raise (30-45 min)
  • No microsurgery required
  • Can be done under local/regional in sick patients
• Disadvantages:
  • Bulky (especially in men)
  • Limited arc to upper head/neck
  • Donor site visible
  • Stiff, limited mobility
• Pearls:
  • Can be based on secondary pedicles if primary divided (turnover flap for sternum)
  • Skin paddle reliability lower than muscle (30% partial skin necrosis)
  • Deltopectoral flap (fasciocutaneous, internal mammary perforators) is separate flap

8. Rectus Abdominis

• Type: Myocutaneous (Mathes & Nahai Type III - two dominant pedicles)
• Vessel: Deep inferior epigastric (DIEA) or superior epigastric (SEA)
• Variations:
  • TRAM (Transverse Rectus Abdominis Myocutaneous): Pedicled or free, includes entire or majority of muscle
  • MS-TRAM (Muscle-Sparing): Preserves majority of muscle, takes only muscle around perforators
• Utility:
  • Breast reconstruction
  • Pelvic reconstruction
  • Chest wall reconstruction
• Trend: Largely replaced by DIEP to reduce donor morbidity (hernia rates 10-20% vs 1-5%)

9. Scapular/Parascapular

• Type: Fasciocutaneous or osteocutaneous
• Vessel: Circumflex scapular artery (branch of subscapular artery)
• Anatomy:
  • Emerges through triangular space (teres major, teres minor, long head triceps)
  • Horizontal (scapular) or vertical (parascapular) skin paddle
  • Can include scapular bone
• Advantages:
  • Large pedicle (3-4mm diameter, 10-12cm length)
  • Concealed donor site (back)
  • Can include bone (scapular tip/lateral border)
  • Two-team approach possible
• Disadvantages:
  • Positioning (lateral/prone) - limits simultaneous flap harvest and defect preparation
  • Bulkier than radial forearm
• Utility: Head and neck, upper limb, composite defects

10. Medial Sural Artery Perforator (MSAP)

• Type: Perforator flap
• Vessel: Medial sural artery perforators from popliteal artery
• Anatomy: Posterior calf, between gastrocnemius heads
• Utility:
  • Small-medium defects
  • Heel reconstruction
  • Hand coverage
• Advantages:
  • Concealed donor site
  • Fasciocutaneous (no muscle sacrifice)
  • Can be pedicled or free
• Size: Up to 15x6cm (larger may not close primarily)

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10. Evidence and Guidelines

Key Guidelines

BOAST 4 (British Orthopaedic Association) [17]

Revised 2017 - The Management of Severe Open Lower Limb Fractures:

• Debridement of open fractures within 12-24 hours
• Soft tissue cover (flap) within 72 hours of injury
• Definitive fixation and cover at same sitting ("Fix and Flap")
• Impact: Reduces infection rates from 40% to less than 10%
• Grade IIIB fractures (bone exposed, periosteum stripped) require flap coverage

NICE Guidelines - Breast Reconstruction (NG101, 2018) [18]

• Offer immediate reconstruction where oncologically appropriate
• Discuss all options (Implant-based vs Autologous)
• DIEP is preferred over TRAM to preserve muscle function and reduce donor morbidity
• Shared decision-making regarding timing and technique
• Provide written information and peer support

BAPRAS Guidelines

• Standards for breast reconstruction
• Quality assurance for microsurgery
• Minimum case numbers for consultant-level training (30 free flaps as primary surgeon)

Evidence Base

Early vs Late Flap Coverage - Godina's Principle [12]

Marko Godina's landmark paper (1986) studied 532 patients with lower extremity trauma:

Established principle: Early flap coverage significantly reduces infection, non-union, and flap failure rates. Now standard of care (BOAST 4).

DIEP vs TRAM - Meta-analyses [19]

Multiple systematic reviews and meta-analyses comparing perforator vs myocutaneous flaps:

Conclusion: DIEP reduces donor morbidity without compromising flap outcomes. Now gold standard for autologous breast reconstruction.

Anticoagulation in Microsurgery [15]

Systematic review of 37 studies, > 10,000 flaps:

• Aspirin alone: Reduced thrombosis (OR 0.57, p=0.02), no increased bleeding
• Heparin alone: No clear benefit, increased bleeding risk
• Combined therapy: May benefit high-risk cases but increased bleeding
• Timing: Starting aspirin pre-op or immediately post-op equally effective
• Recommendation: Aspirin 75-300mg daily is standard, continue 2-4 weeks

Free-Style Perforator Flaps [20]

Described by Fu-Chan Wei and Samir Mardini:

• Using handheld Doppler to find any audible perforator and raising a flap based on it
• Frees surgeon from defined anatomical landmarks
• Allows customization for specific defect requirements
• Requires advanced microsurgical skills
• Success rates comparable to established flaps (95-97%)

Perforasome Theory - Saint-Cyr et al [21]

Advanced Angiosome theory published 2009:

• Details how perforators interact via "linking vessels"
• Direct linking vessels: Same source artery, adjacent perforasomes
• Indirect linking vessels: Choke vessels between different angiosomes
• Explains perfusion patterns in perforator flaps
• Allows more accurate prediction of flap viability
• Basis for "mega-flaps" (multiple perforasomes on single pedicle)

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11. Examination Focus

Common Exam Questions (FRCS Plast)

1. Classify the blood supply to the Latissimus Dorsi muscle.

   • Answer: Mathes & Nahai Type V. Dominant pedicle is Thoracodorsal artery (branch of subscapular); secondary segmental pedicles from lumbar and intercostal vessels (9th-11th). This allows the muscle to survive on secondary pedicles when distally based (turnover flap for paraplegia) or on the dominant pedicle when used as pedicled or free flap.

2. Describe the surface markings and anatomy for the DIEP flap perforators.

   • Answer: Perforators are concentrated in the periumbilical region, typically 2-8cm lateral to the umbilicus. There are medial and lateral rows of perforators. The medial row (usually larger and more consistent) is located at the lateral border of the rectus muscle, while the lateral row is at the lateral edge. I would use a handheld Doppler pre-operatively and ideally a CT Angiogram to map the specific perforators, their course through the rectus muscle, and caliber. This guides optimal perforator selection and surgical planning.

3. A free flap is purple and tense 6 hours post-op. What is your management?

   • Answer: This indicates venous congestion. This is a surgical emergency. I would immediately:
     1. Bedside assessment: Check vitals, ensure adequate resuscitation, elevate the head/limb, remove any constrictive dressings or sutures
     2. Clinical examination: Assess color (purple/blue), turgor (tense), capillary refill (brisk less than 1sec), scratch test (dark venous blood)
     3. Doppler assessment: Check for arterial signal (should be present) and venous signal (may be abnormal)
     4. If no immediate improvement with simple measures, urgent return to theatre for exploration. This must be within 6 hours for best salvage rates.
     5. In theatre: Explore venous anastomosis, thrombectomy if thrombus present, revision of anastomosis if technical issue, consider additional venous drainage (superdrainage)
     6. If surgical revision not possible or fails: Medicinal leech therapy with ciprofloxacin cover.

4. Explain the "Angiosome Concept" and its relevance to flap delay.

   • Answer: Taylor and Palmer (1987) described the body as divided into approximately 40 three-dimensional composite blocks of tissue (skin, fat, fascia, muscle, bone), each supplied by a specific source artery - this is an angiosome. Adjacent angiosomes are connected by "choke vessels" (reduced caliber vessels at boundaries).

     A flap can safely capture its primary angiosome and usually the adjacent angiosome (via choke vessels opening). However, capturing a third angiosome (one removed from the source) is unreliable.

     A delay procedure (1-3 weeks prior to definitive transfer) works through: (1) Sympathectomy causing vasodilation, (2) Choke vessel dilation and reorientation into true anastomotic channels, and (3) Ischaemic conditioning (HIF-1α upregulation, VEGF release) making tissue more tolerant to hypoxia. This allows safe capture of further territory that would otherwise necrose.

5. What are the indications for leech therapy and what precautions are essential?

   • Answer: Indications: Venous congestion that is not amenable to surgical correction:

     • Distal tip congestion
     • Diffuse microvascular insufficiency
     • Replantation with venous insufficiency
     • Failed surgical revision of venous anastomosis

     Mechanism: Hirudo medicinalis injects hirudin (anticoagulant) and hyaluronidase, draws 5-10ml blood, and promotes continuous oozing for hours.

     Essential precautions:

     • Mandatory antibiotic prophylaxis: Ciprofloxacin 500mg BD or Co-trimoxazole (covers Aeromonas hydrophila - gut commensal of leech that causes serious wound infection)
     • Monitor Hb daily (significant blood loss possible)
     • Transfuse if needed
     • Continue for 3-7 days until neovascularisation occurs
     • Typically 2-3 leeches every 4-6 hours

6. Describe the zones of a TRAM/DIEP flap and their clinical significance.

   • Answer: Hartrampf described 4 zones based on blood supply:

     • Zone 1: Ipsilateral directly over the pedicle (best perfusion)
     • Zone 2: Ipsilateral across midline (good perfusion via direct perforators)
     • Zone 3: Contralateral over opposite pedicle territory (fair perfusion via choke vessels across midline)
     • Zone 4: Contralateral lateral (poorest perfusion - two angiosomes away)

     Clinical significance: This determines which tissue can be safely included. Zone 1 is always safe. Zone 2 is reliable. Zone 3 may have edge necrosis (10-15% fat necrosis). Zone 4 is often discarded or requires "supercharging" (additional arterial anastomosis to contralateral DIEA) to survive.

7. What are the key differences between DIEP and TRAM flaps? What does the evidence show?

   • Answer:

     • DIEP: Perforator flap - spares rectus abdominis muscle, only takes skin/fat with perforators dissected through muscle
     • TRAM: Myocutaneous flap - includes rectus muscle

     Evidence (multiple meta-analyses):

     • Donor morbidity: DIEP 1-5% hernia/bulge vs TRAM 10-20% (pless than 0.001)
     • Flap survival: Equivalent (95-98% both)
     • Operative time: DIEP 30-60 min longer (perforator dissection)
     • Fat necrosis: Similar (10-15%)
     • Abdominal wall strength: Better preserved with DIEP

     Conclusion: DIEP is now gold standard (NICE guidelines) - reduces donor morbidity without compromising flap outcomes.

8. Describe your approach to pre-operative planning for a free fibula flap for mandible reconstruction.

   • Answer: Imaging:

     • CT angiogram to assess: (1) Peroneal artery caliber and course, (2) Three-vessel runoff to foot (AT, PT, peroneal - need at least 2), (3) Skin perforator locations, (4) Length of fibula available
     • If peroneal is dominant/only vessel to foot → contraindication

     Clinical:

     • Peripheral vascular disease assessment
     • Donor leg preference (non-dominant if bilateral suitable)
     • Consent: ankle instability, foot drop risk, sensory loss

     Defect planning:

     • Mandible length needed (typically 10-15cm)
     • Number and location of osteotomies (to shape curve)
     • Soft tissue requirement (skin paddle size/location)
     • Dental rehabilitation plans (implants possible 6-12 months later)

     Recipient vessels:

     • Facial artery/vein (most common)
     • Superior thyroid
     • Lingual vessels
     • Assess prior surgery/radiotherapy impact

Viva Points

Viva Point: Opening Statement for Flap Choice: "My choice of reconstruction depends on three key factors: defect analysis (what tissue is missing - lining, cover, bone, function), patient factors (age, comorbidities, smoking status, available donor sites), and available resources (microsurgical capabilities, operative time, intensive care). I employ the principle of the 'Reconstructive Elevator' to select the optimal reconstruction for this specific patient and defect, rather than simply the simplest option."

Key facts to mention:

• Godina's principle: less than 72 hours for trauma reduces infection from 17.5% to 1.5%
• Free flap success rates: 95-98% in experienced centres
• Mathes & Nahai classification for muscle flaps (5 types)
• Importance of smoking cessation (4 weeks ideal)

Viva Point: Free Flap Monitoring Protocol: "I would institute a strict, standardized monitoring protocol. For the first 24-48 hours, hourly observations including: color (should be pink), temperature (> 30°C), capillary refill (2-3 seconds), turgor (soft), and Doppler signal (arterial and venous).

I would ensure the patient is kept warm (> 22°C ambient, Bair Hugger), adequately hydrated (hyperdynamic circulation), has good analgesia (prevents catecholamine-induced vasospasm), and appropriate positioning (head up 30° for H&N, avoid pedicle kinking).

Critically, I would empower the nursing staff to escalate immediately if any deviation from normal - time is tissue. Salvage rates are 50-70% if revised within 6 hours, dropping significantly after this golden period."

Viva Point: Flap Failure Management - Arterial vs Venous: "The critical distinction is arterial versus venous failure, as they have different presentations and management:

Arterial insufficiency: Pale/white flap, cool, slow/absent capillary refill, no bleeding on scratch test. Urgent exploration, check for thrombosis/spasm/kinking. Thrombectomy and anastomotic revision. May need papaverine/warm irrigation for spasm.

Venous congestion: Purple/blue flap, warm initially, rapid capillary refill (less than 1sec), dark blood on scratch test, tense/swollen. Urgent exploration of venous anastomosis. Thrombectomy/revision. If not amenable to surgical correction, consider medicinal leech therapy with mandatory ciprofloxacin prophylaxis for Aeromonas.

Both require return to theatre within 6 hours for optimal salvage."

Model Answers

Q: A 45-year-old woman undergoes immediate breast reconstruction with DIEP flap. On day 2 post-op, the flap becomes dusky purple at the lateral edge. Describe your management.

A: "This presentation suggests venous congestion, specifically of Zone 3/4 tissue supplied via choke vessels across the midline with inadequate venous drainage.

Immediate assessment:

• Bedside evaluation: Check vital signs (ensure adequate perfusion pressure), positioning (ensure no compression), remove any constrictive dressings
• Clinical examination: Color (purple), temperature (warm), capillary refill (rapid less than 1sec), turgor (tense), scratch test (dark venous blood with brisk bleeding)
• Handheld Doppler: Check for arterial signal (should be present - rules out arterial insufficiency) and venous signal
• If implantable Doppler present: Check for signal loss

Management decision: If this is limited to the lateral zone (Zone 4) only:

• Close observation as this tissue may autoamputate without compromising core zones 1-2
• Ensure optimal conditions (warm, well perfused, head elevated 30 degrees)
• Monitor closely for progression

However, if:

• Congestion is progressive or involving more central zones (2-3)
• Implantable Doppler shows signal loss
• Clinical deterioration over 1-2 hours

Then this is an urgent surgical indication.

Surgical exploration: In theatre, I would:

1. Assess the venous anastomosis for thrombosis, kinking, or compression
2. Perform thrombectomy if thrombus present (Fogarty or milking technique)
3. Consider anastomotic revision if technical issue
4. Review pre-operative CTA - if superficial venous system was dominant, may need to anastomose superficial inferior epigastric vein (SIEV)
5. Consider superdrainage (additional venous anastomosis)

If surgical revision is not possible or fails, I would institute medicinal leech therapy with ciprofloxacin 500mg BD prophylaxis (covers Aeromonas hydrophila)."

Q: A 25-year-old motorcyclist has a Gustilo IIIB open tibial fracture with a 15cm wound exposing bone at the middle third. Describe your reconstructive approach.

A: "This is a severe open fracture requiring urgent, coordinated management following BOAST 4 guidelines.

Initial Management (First 24 hours):

• Resuscitation and assessment of polytrauma
• Photograph wound, betadine-soaked dressing
• IV antibiotics (co-amoxiclav + gentamicin or cephalosporin + gentamicin)
• Tetanus prophylaxis
• Urgent surgical debridement within 6-12 hours: thorough washout, debride all devitalized tissue, preserve length

Definitive Management (Within 72 hours - Godina principle): Based on BOAST 4, I would aim for definitive skeletal fixation and soft tissue coverage in a single sitting ("Fix and Flap") within 72 hours. This reduces infection risk from 40% to less than 10%.

Skeletal Stabilization (Orthopaedic team):

• External fixation or intramedullary nail depending on fracture pattern
• Ensure stability before flap coverage

Flap Choice for 15cm middle third tibial defect: Given the large defect size and middle third location, my options are:

Pedicled flaps:

• Gastrocnemius: Limited reach (proximal third only)
• Soleus: Can cover middle third but may be insufficient for 15cm defect

Free flaps (preferred for this case):

1. Latissimus Dorsi (my preference):

   • Provides large, reliable coverage
   • Robust Type V blood supply
   • Well-vascularized tissue delivers oxygen, antibiotics, immune cells to fight infection
   • Can cover entire 15cm defect with ease

2. ALT:

   • Large, versatile
   • Adequate bulk
   • Good alternative

3. Rectus Abdominis:

   • Reliable
   • Good bulk
   • Higher donor morbidity

Recipient vessels: Typically posterior tibial vessels (assess intra-operatively, may be damaged - have alternatives ready)

Outcome: With early coverage (less than 72h), infection risk drops to less than 10%, flap success > 95%, and union rates improve significantly.

Follow-up: Close monitoring for flap viability (first 48h critical), fracture union, infection, rehabilitation."

Common Mistakes

• ❌ Waiting too long to explore a compromised flap. "Let's see how it looks in the morning" is the wrong answer - salvage rates drop dramatically after 6 hours.
• ❌ Forgetting donor site morbidity. Candidates often focus on the defect and forget the "cost" of the flap (e.g., foot drop from fibula 1-2%, hernia from TRAM 10-20%, visible forearm scar from radial forearm).
• ❌ Confusing classifications. Ensure you know Mathes & Nahai (Muscle - 5 types: T-G-G-S-L) vs Cormack & Lamberty (Fasciocutaneous - 3 types: A-B-C).
• ❌ Not knowing current evidence. Citing outdated practices (e.g., routine TRAM instead of DIEP, or delayed flap coverage for trauma beyond 72h) will fail you.
• ❌ Poor systematic approach. Always: patient factors → defect analysis → reconstructive options → donor site assessment → choice of optimal reconstruction. Not following a system shows poor surgical thinking.
• ❌ Ignoring contraindications. Not checking Allen's test for radial forearm, or not getting CTA for fibula, shows dangerous surgical planning.
• ❌ Inadequate flap monitoring knowledge. Not knowing the signs of arterial vs venous failure, or what to do immediately, is unacceptable.
• ❌ Forgetting leech prophylaxis. Mentioning leech therapy without ciprofloxacin for Aeromonas is a red flag error.

High-Yield Topics for Viva Preparation

1. Angiosome theory and delay phenomenon - Taylor & Palmer, pathophysiology, clinical applications
2. Mathes & Nahai classification - All 5 types with examples, clinical implications, mnemonic
3. DIEP vs TRAM - Evidence for perforator-sparing, meta-analysis results, NICE guidance
4. Flap monitoring - Clinical signs, technology (Doppler, oximetry), salvage protocols, timing
5. Godina's principle - less than 72h coverage, evidence, BOAST 4 implementation
6. Leech therapy - Indications, mechanism, mandatory antibiotic prophylaxis, protocol
7. Specific flap anatomy - ALT, DIEP, fibula, radial forearm (know vessels, dimensions, donor morbidity)
8. Ischaemia-reperfusion injury - Mechanism, safe ischaemia times by tissue type
9. Venous vs arterial failure - Differentiation, immediate management, surgical exploration
10. Reconstructive ladder vs elevator - Modern philosophy, appropriate escalation

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12. References

1. Khouri RK, et al. Complications of microvascular breast reconstruction: 15-year experience. Plast Reconstr Surg. 2008;121(4):1141-1148. doi:10.1097/PRS.0b013e318168c747

2. Albornoz CR, et al. A paradigm shift in U.S. breast reconstruction: increasing implant rates. Plast Reconstr Surg. 2013;131(1):15-23. doi:10.1097/PRS.0b013e3182729cde

3. British Orthopaedic Association (BOA). BOAST 4: The Management of Severe Open Lower Limb Fractures. Revised 2017.

4. Karakida K, et al. Analysis of 295 free flap transfers in head and neck reconstruction. J Craniofac Surg. 2013;24(6):1957-1961. doi:10.1097/SCS.0b013e3182a24712

5. Macadam SA, et al. Quality of Life in Breast Reconstruction: A Meta-Analysis. Plast Reconstr Surg. 2016;137(5):1416-1430. doi:10.1097/PRS.0000000000002073

6. Gopal S, et al. The management of severe open tibial fractures. J Bone Joint Surg Br. 2000;82(7):959-966. doi:10.1302/0301-620x.82b7.11433

7. Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg. 1989;84(1):71-79. doi:10.1097/00006534-198907000-00014

8. Taylor GI, Palmer JH. The vascular territories (angiosomes) of the body: experimental study and clinical applications. Br J Plast Surg. 1987;40(2):113-141. doi:10.1016/0007-1226(87)90185-8

9. Dharamdasani T, et al. The physiology of the surgical delay phenomenon. J Plast Reconstr Aesthet Surg. 2012;65(7):851-856. doi:10.1016/j.bjps.2012.01.002

10. Mathes SJ, Nahai F. Classification of the vascular anatomy of muscles: experimental and clinical correlation. Plast Reconstr Surg. 1981;67(2):177-187. doi:10.1097/00006534-198102000-00001

11. Cormack GC, Lamberty BG. A classification of fasciocutaneous flaps according to their patterns of vascularisation. Br J Plast Surg. 1984;37(1):80-87. doi:10.1016/0007-1226(84)90049-3

12. Godina M. Early microsurgical reconstruction of complex trauma of the extremities. Plast Reconstr Surg. 1986;78(3):285-292. doi:10.1097/00006534-198609000-00001

13. Giele H, et al. Anastomotic devices in microsurgery. J Plast Reconstr Aesthet Surg. 2018;71(8):1095-1104. doi:10.1016/j.bjps.2018.04.015

14. Kubo T, et al. Tissue oximetry for free flap monitoring. Plast Reconstr Surg. 2017;140(3):456e-465e. doi:10.1097/PRS.0000000000003613

15. Chien W, et al. Antithrombotic agents in free flap surgery: a meta-analysis. J Plast Reconstr Aesthet Surg. 2019;72(9):1491-1499. doi:10.1016/j.bjps.2019.05.015

16. Whitaker IS, et al. Hirudo medicinalis and the plastic surgeon. Br J Plast Surg. 2004;57(4):348-353. doi:10.1016/j.bjps.2004.01.004

17. British Orthopaedic Association. BOAST 4: The Management of Severe Open Lower Limb Fractures. Revised 2017.

18. NICE. Breast cancer: diagnosis and management (NG101). 2018.

19. Gill PS, et al. A 10-year retrospective review of 758 DIEP flaps for breast reconstruction. Plast Reconstr Surg. 2004;113(4):1153-1160. doi:10.1097/01.prs.0000110328.32426.68

20. Blondeel PN, et al. The "freestyle" free flap. Plast Reconstr Surg. 2003;112(7):23S-35S. doi:10.1097/01.PRS.0000091244.75333.6C

21. Saint-Cyr M, et al. The perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg. 2009;124(5):1529-1544. doi:10.1097/PRS.0b013e3181b98a6c

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