Transplant Surgery, Skin graft & Flaps😍

Transplant Surgery

Types of Grafts

• Autograft: Graft from same person (e.g., skin graft)

• Isograft: Graft from identical twin (e.g., kidney transplant)

• Allograft: Graft from same species

• Xenograft: Graft from different species

Maastricht Classification: Deceased Donor Categories

• Transplantation rules are Very Strict (Maastricht)

• Strict DR ABU

• 3, 4, 5 → Admit Patients → Don't take heart

• Brought Dead → Take heart and eyes

• Failed resuscitation → heart, eyes, kidney

Flushing of UW Solution

• UW solution at 4°C flushed through aorta for static cold storage

Key components	Function
Hydroxyethyl starch	↓ edema
Lactobionic acid	↓ edema
Adenosine	Energy
Allopurinol / Glutathione	Antioxidants

• Advantages:
• Flushes out blood (prevents thrombosis)
• Cools organs (↓metabolic needs)
• Replaces ECF with preservative fluid

• Disadvantage: 
• Delayed graft function

Cold ischemia time:

• Longest for kidney (24-36 hrs)

• Shortest for heart (3-6 hrs) > Lung

Normothermic Machine Perfusion

• Used for heart, lung, liver & kidney perfusion

• Provides a more physiological environment

• Advantage: Early allograft function (replenishes depleted ATPs)

Renal Transplant

Indications

• M/c in adults: Diabetic nephropathy

• M/c in children: Glomerulonephritis

• Side: Left kidney → Longer vein

• Heterotrophic

Extended Donor Criteria

• Fit patient >60 years OR 

• All fit patients >50 with two or more of:
• Death due to stroke
• H/o HTN
• Serum creatinine >1.5 mg/dL

Dual Kidney Transplant

• Transplantation of a pair of marginal quality kidneys from one donor into one recipient for adequate nephron mass

• Usually transplanted in same iliac fossa

• Used in elderly DCD donors or expanded donor criteria

Anastomosis

• Heterotopic (iliac fossa)

• Structures anastomosed:
• Ureter-Bladder
• Renal vein-External iliac vein
• Renal artery
• Dead → External iliac artery (end to side)
• Living → Internal iliac A (end to end)
• Keep dead to side and externally
• Keep living inside till end

Contraindications for RENAL Transplant

Complications OF RENAL TRANSPLANT

Definition

• Acute graft rejection:
• ↑ Serum creatinine by >10% from baseline.

• Acute graft dysfunction:
• Either
• ↑ Serum creatinine
• >10% from baseline
• Or ≥20 µmol/L absolute rise

Causes of Early Graft Dysfunction

• Acute rejection
• Antibody-mediated
• T-cell-mediated

• Calcineurin inhibitor toxicity

• Dehydration

• UTI or pyelonephritis

• Sepsis

• Renal vein or renal artery thrombosis

• Ureteric obstruction

• Urine leak

Graft Rejection Types:

Rejection Type	Timeframe	Note	Pathology
Hyperacute Mnemonic: 2 days → Type 2 → too many pregnancies and transfusions → 2 necrosis	Within 48 hours Dusky kidney on table Type 2	preformed anti-HLA antibodies in recipient (e.g., multiparous women, multiple transfusions). Graft must be removed	Coagulative necrosis  (solid organs like kidney),  Fibrinoid necrosis  (blood vessels). Cyanotic and mottled graft with pale white areas Neutrophil accumulation Intravascular thrombosis
Acute	Weeks to months Type 2 (humoral) & Type 4 (cellular)	90% 5-year graft survival Prevent/reverse with immunosuppressants	Humoral:  - C4d deposition in blood vessels (rejection vasculitis). Cellular:  - Endothelitis (blood vessels),  - Tubulitis (tubules).
Chronic	Months to years Type 4 (primarily)	Most common rejection type. 6 months post-transplant HPE: Glomerular sclerosis	Kidney pathology GOATI - Glomerular BM → duplication,  - Tubules → Atrophy - Blood vessels → obliterate - Interstitium → Fibrosis Organ-specific examples: - Chronic allograft nephropathy - Bronchiolitis obliterans - Accelerated atherosclerosis (heart) → Most important long-term → allograft arteriopathy, also known as cardiac allograft vasculopathy (CAV) - Vanishing bile duct syndrome

Category	Acute humoral rejection	Acute cellular rejection
Mediated by	Newly synthesized antibodies	CD4 & CD8 T cells
Type of hypersensitivity	Type II	Type IV
Pathogenesis	Immune complex formation → Complement activation	Donor APC's present Ag to recipient's CD4 & CD T cells
H&E	Deposition of C4d in capillaries Fibrinoid necrosis in vessels → Rejection vasculitis	Tubulitis, Endothelitis
marker	C4d (Complement breakdown product)	-
Response to immunosuppressants	No response to increasing dose	Responsive

Swyer James Mcleod syndrome

• Post bronchiolitis obliterans.

• decreased vessel markings

• Mnemonic: Mcleod syndrome → Makkalkk varunna syndrome

Graft Versus Host Disease (GVHD):

• Occurs when: 
• Graft (immunocompetent) attacks recipient (immunocompromised).

• Timeline (definitive):
• Acute GVHD:
• < 100 days.
• Chronic GVHD:
• > 100 days.
• Mnemonic:
• Graft → Greeshma → Kashayam Greeshma
• 100 days of love (Kidney is love)
• After that → Try to kill him with poison ()
• Diarrhea
• Rash
• Jaundice

• Organs Attacked: 
• Skin (rash), Intestine (diarrhea), Liver/Hepatobiliary (jaundice).
• Mnemonic: SIL

Prevention

• Irradiation of blood products, including RBCs, is done.

Purpose of Irradiation:

• Damages donor lymphocyte DNA.

• Prevents lymphocyte proliferation.

• Prevents immune response by inactivating donor lymphocytes.

Which organ has the highest chances of Graft rejection response?
A. Cornea
B. Gut
C. Liver
D. Skin

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Most important HLA:

• HLA DR

HLA matching is not required in

• Cornea

• Lung

• Heart

• Testis/seminiferous tubules

• Brain

Other Complications

• Infection:
• Maximum in first 6 months
• M/c in 1st month: Bacterial
• M/c overall: Viral (M/c CMV)

• Malignancy: Skin cancer (SCC)

• Post-transplant lymphoproliferative disorder (PTLD): 
• D/t EBV (B-cell mediated)

• Renal vein thrombosis: M/c vascular complication

Liver Transplant

Indications

• M/c in adults: Cirrhosis

• M/c in children: EHBA

• Note: HLA matching is not important

Types

• Dead donor liver transplant (DDLT)

• Live donor liver transplant (LDLT)

• Split LT:
• Segments 2+3 to child - Lateral left lobe
• 1+4+5+6+7+8 to adult - Extended right lobe

• Reduced size LT:
• Resection of a full size liver
• To fit into smaller abdominal cavity of child/adult

• Auxiliary LT:
• Recipient’s liver not removed;
• donor liver piggybacks existing liver
• HALT (Heterotropic Auxillary LT)
• Metabolic indications
• APOLT (Auxillary Partial Orthotrophic LT)
• Orthotrophic [in the liver → better regeneration]
• mushroom toxicity
• PCM toxicity

• Domino LT:
• Deposits → Maple syrup, Amyloidosis, Wilson
• Donor & recipient suffer same systemic disease

• Paired exchange program

Sequence of Anastomosis

• Suprahepatic IVC → Infrahepatic IVC → Portal vein → Hepatic artery → Bile duct

• Vein → Artery → Duct

Complications

• Chronic rejection: 
• Vanishing duct syndrome

• Hepatic artery thrombosis

• Infections

• PTLD

• Cancer

Liver Transplant for Hepatic Malignancy

• LT simultaneously treats both the tumor & underlying cause

• Milan criteria for HCC:
• One lesion ≤ 5cm
• Two to three lesions ≤3 cm
• No vascular invasion
• No metastatic disease

• Candidates:
• Children with hepatoblastoma & HCC (M/c)
• Liver metastasis from colorectal & neuroendocrine tumors

Contraindications for Liver Transplant

Heart Transplant

• Sequence of anastomosis: 
• Lt. atrium → Rt. atrium → Pulmonary artery → Aorta

• Suspecting rejection: Subendocardial biopsy

Graft

Graft Survival

Types of Grafts

Graft Failure

• M/c cause: Seroma/hematoma formation

• Infection

• Movement/shearing force

• Poor recipient bed:
• Excessive granulation tissue
• Lack of periosteum
• Infected recipient bed

Flaps

Flap Fundamentals

• Independent blood supply

Types of Flaps

Random Flaps:

• Based on dermal vessels

• Examples: V-Y plasty, Z-plasty

• Used for wound elongation

• Helps in post-burn contractures

• Rhomboid/Limberg flap: 
• Type of random flap, used in pilonidal sinus

Axial Flap:

• Based on known blood vessels

• Deltopectoral flap: 
• Used for floor of mouth reconstruction

• Pectoralis major myocutaneous flap (PMMF): 
• M/c used in head & neck surgery

• Latissimus dorsi flap: 
• Based on thoracodorsal pedicle

Abdominal Flaps:

TRAM Flap (Transverse Rectus Abdominis Myocutaneous Flap):

• Increased abdominal wall morbidity (muscle removed)

• Uses muscle

• ↑ risk of incisional hernias

• Mnemonic: traM → has M → Muscle in it

DIEP Flap (Deep Inferior Epigastric Artery Perforator Flap):

• Best flap for breast reconstruction

• Only skin + fat

• Decreased abdominal wall complications (muscle not removed)
• No abdominal wall weakness

Free Flap:

• Disconnected from donor site

• Anastomosed at recipient site

• Radial artery forearm flap: 
• Used for head & neck surgery,
• requires prior Modified Allen’s test

• Free fibular flap: 
• Based on peroneal vessels,
• used for mandibular reconstruction

Mathes and Nahai Classification for Axial Flaps

• Type I: 
• 1 dominant pedicle
• Examples: Gastrocnemius, rectus femoris, tensor fascia lata

• Type V: 
• 1 dominant, multiple minor pedicles
• Examples: Pectoralis major, latissimus dorsi

Flap Failure

• Caused by vessel blockade