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Nevus Cutaneous Lipomatosus Superficialis (NCLS)

Detailed Clinical Note for MS General Surgery Poster Presentation

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1. DEFINITION & NOMENCLATURE

• First described by Hoffmann and Zurhelle in 1921
• Classified under connective tissue hamartomas / benign mesenchymal neoplasms
• ICD-10: D22.9 / Q82.8 (benign melanocytic nevus / other specified congenital malformations of skin)

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2. EPIDEMIOLOGY

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3. PATHOGENESIS & ETIOLOGY

1. Hamartomatous differentiation — aberrant differentiation of pluripotent mesenchymal cells in the dermis into mature adipocytes
2. Ectopic lipogenesis — perivascular connective tissue or fibroblast precursors undergo lipogenesis under unknown stimuli
3. Nevoid malformation — considered a localized developmental error (nevoid origin) rather than a true neoplasm
4. Embryological arrest theory — arrest of maturation of dermal mesenchymal cells during fetal development, retaining adipogenic potential
5. Some authors postulate a somatic mutation in PTEN or PIK3CA pathway (analogous to other hamartomas), though not definitively proven

No proven association with systemic lipomatosis, chromosomal abnormalities, or malignant transformation.

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4. CLASSIFICATION

Type I — Classic / Hoffmann-Zurhelle Type (Zosteriform / Multiple)

• Multiple soft, yellowish, skin-colored papules and nodules grouped in a cerebriform, zosteriform, or clustered configuration
• Present at birth or appears in childhood/early adulthood (before age 30)
• Typically located on the lower trunk (lumbo-gluteal region, buttocks, flanks, thighs)
• Lesions may coalesce forming plaques with a cobblestone or cerebriform surface
• Does not cross the midline (follows Blaschko's lines in some cases)

Type II — Solitary / Acquired Type

• Single, dome-shaped soft pedunculated nodule or papule
• Appears in adults (3rd–5th decade)
• Can occur anywhere — scalp, face, ear (tragus), trunk, extremities
• Smaller, more discrete than Type I
• The histopathology image above shows this type — a pedunculated nodule on the tragus

A third rare variant — associated with folliculosebaceous cystic hamartoma and comedone-like lesions has been described.

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5. CLINICAL FEATURES

Symptoms

• Usually asymptomatic
• Occasionally: mild pruritus, tenderness on pressure, cosmetic concern
• No constitutional symptoms

Signs

Associated Features (Type I)

• Telangiectasia within plaques
• Hyperpigmentation or hypopigmentation
• Comedone-like plugs at follicular ostia
• Focal alopecia over lesional skin

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6. HISTOPATHOLOGY

Microscopic Features:

Key Histological Diagnostic Criterion:

Mature adipocytes occupying >10% of the dermis, present in the upper/mid reticular dermis without connection to subcutaneous fat — Diagnostic hallmark

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7. DERMOSCOPY

• Yellowish-white structureless areas corresponding to dermal fat deposits
• Dilated follicular ostia
• Fine vessels in a reticular pattern
• No pigment network (differentiates from melanocytic lesions)
• Helpful non-invasive pre-operative tool

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8. IMAGING

Imaging is rarely needed but useful for large lesions or when liposarcoma is a concern.

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9. DIAGNOSIS

Clinical Diagnosis:

• Based on characteristic morphology and location
• Type I (zosteriform multiple lesions over buttocks in a young patient) is often clinically diagnosed

Definitive Diagnosis:

• Excisional biopsy + Histopathology — required for confirmation, especially solitary lesions

Diagnostic Criteria (Proposed):

1. Soft, skin-colored/yellowish papules/nodules in dermis
2. No connection to subcutaneous fat clinically or histologically
3. Mature adipocytes in the dermis on histology
4. No atypia or malignant features

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10. DIFFERENTIAL DIAGNOSIS

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11. MANAGEMENT

Indications for Surgery:

1. Cosmetic disfigurement / patient request
2. Mechanical symptoms (friction, difficulty wearing clothing)
3. Diagnostic uncertainty (to rule out malignancy)
4. Pedunculated lesion prone to trauma/torsion
5. Rapid increase in size (though rare)

Surgical Treatment:

Wide Local Excision (Treatment of Choice)

• Excision with adequate margins down to and including upper subcutaneous fat
• Full-thickness skin excision ensures complete removal of all ectopic fat lobules
• Orientation of incision along Langer's lines for optimal cosmesis
• Closure: primary closure for small lesions; flap or skin graft for large plaques

Liposuction (Adjunctive)

• Used for large, extensive Type I lesions (zosteriform plaques)
• Reduces bulk and improves contour
• Risk of recurrence higher than excision alone
• May be combined with excision

CO₂ Laser Ablation

• Reported for small, superficial lesions
• Less scarring but incomplete depth of treatment → higher recurrence
• Not standard of care for MS General Surgery

Nd:YAG Laser

• Limited evidence; experimental

Recurrence:

• Low recurrence rate with complete excision
• Incomplete excision → local recurrence
• No malignant transformation reported

Prognosis:

• Excellent — purely benign lesion
• No systemic involvement
• No malignant potential
• Psychosocial impact addressed by surgical correction

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12. COMPLICATIONS

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13. SPECIAL CONSIDERATIONS FOR SURGEONS

• Always send specimen for HPE — mandatory to confirm benignity
• For gluteal/lower trunk lesions: position patient prone, use tourniquet if needed for hemostasis, plan incision for ease of closure
• For solitary lesions on face/ear: consider cosmetic implications, use loupe magnification, ensure clean margins
• Rule out liposarcoma in any atypical or rapidly growing lesion — send for MDM2/CDK4 FISH if histologically borderline
• No role for chemotherapy, radiotherapy, or immunotherapy — purely surgical condition

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14. SUMMARY TABLE

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CROSS QUESTIONS & ANSWERS FOR POSTER PRESENTATION

(Expected from MS General Surgery Professor)

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1. Perform a preoperative MRI to delineate extent and rule out deep infiltration
2. Plan wide local excision with margins under GA, patient in prone position
3. Ensure full-thickness skin excision to the upper subcutaneous fat
4. For very large lesions, consider staged excision or liposuction for debulking followed by excision of residual skin
5. Closure with rotation flap or split-thickness skin graft if primary closure is not possible
6. Send entire specimen for histopathological examination

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• Goltz syndrome is an X-linked condition with widespread skin atrophy, telangiectasias, skeletal abnormalities (syndactyly, osteopathia striata), ocular anomalies, and dental defects. The fat appears through atrophic skin as a herniation.
• NCLS is localized, sporadic, has no systemic associations, no skin atrophy, and the fat is truly within the dermis as a hamartoma, not herniating from subcutaneous tissue.

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• H&E: Shows mature adipocytes — large cells with clear vacuolated cytoplasm and peripherally compressed nuclei
• Oil Red O / Sudan IV: Positive staining for lipid in fresh/frozen sections
• S100: Negative — differentiates from neural tumors
• MDM2/CDK4 immunohistochemistry or FISH: Negative — rules out well-differentiated liposarcoma
• CD34: May show stromal positivity (non-specific)

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1. Ensure full-thickness excision down to and including the superficial subcutaneous fat
2. Confirm clear margins on frozen section if clinically uncertain
3. Avoid superficial shave excision or incomplete removal
4. For liposuction-based treatment of large lesions, counsel patient about higher recurrence rates (~20–30%) compared to excision

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1. Clinical diagnosis — History (since childhood, buttock, multiple, soft, yellow) is strongly suggestive of Type I NCLS
2. Dermoscopy — Yellow-white structureless areas, no pigment network
3. Excisional biopsy of representative lesion — Confirm with HPE
4. Once confirmed benign: counseling — inform patient of benign nature, no malignant potential
5. Surgical excision if cosmetically distressing or symptomatic
6. No systemic workup needed — NCLS has no systemic associations

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1. Review slides with a dedicated dermatopathologist/surgical pathologist
2. Order MDM2 and CDK4 immunohistochemistry — positive in ALT/WDLPS
3. Send for MDM2 FISH — amplification of chromosome 12q13-15 confirms WDLPS
4. If confirmed malignant: re-excision with wide clear margins, oncology referral
5. If negative for MDM2/CDK4: likely benign atypical NCLS — close follow-up with re-excision if incomplete margins

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• Identify the yellowish structureless areas representing dermal fat
• Rule out melanocytic pathology (absence of pigment network)
• Identify dilated follicular openings and reticular vessels
• Guide decision for biopsy (helps clinician avoid unnecessary biopsy of classic cases)
• Not a substitute for histopathology in solitary or atypical lesions

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1. NCLS = benign hamartoma — ectopic mature adipocytes in dermis
2. Two types: Type I (multiple, congenital, buttocks) and Type II (solitary, adult, any site)
3. Diagnosis confirmed by histopathology — mature adipocytes in dermis, no atypia
4. Wide local excision is treatment of choice — curative, low recurrence
5. No malignant potential — reassure patient
6. Exclude well-differentiated liposarcoma in atypical cases via MDM2/CDK4
7. Rare condition — thorough clinico-pathological correlation essential

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QUICK REVISION MNEMONICS

• Dermis — location of ectopic fat
• Ectopic mature adipocytes
• Rare hamartoma (Hoffmann-Zurhelle)
• Multiple (Type I) or Mono/solitary (Type II)
• Innocuous — no malignant potential
• Surgery (wide excision) = cure
• Fat in dermis = pathognomonic
• Adult onset for Type II
• Type I = congenital, zosteriform, buttocks

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Note for Poster: The lesion is purely benign and surgical excision is curative. Always send HPE. The key message for a General Surgery audience is the distinction from liposarcoma and the confirmatory role of histopathology + MDM2/CDK4 testing when in doubt.

Layers of the Abdomen

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ANTERIOR ABDOMINAL WALL — Layers (Superficial to Deep)

Mnemonic: "Some Surgeons Can Find All Patients Extremely Pale, Inspite Prolonged Effort"

Skin → Superficial fascia → Camper's → Scarpa's → Fat → Aponeuroses/Muscles → Fascia Transversalis → Extraperitoneal fat → Peritoneum

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Layer by Layer:

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MUSCLES IN DETAIL

Lateral Group (3 flat muscles):

Medial Group:

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RECTUS SHEATH — Surgical Anatomy

Above Arcuate Line (Upper ¾ of rectus):

Below Arcuate Line (Lower ¼, below level of ASIS):

The Arcuate line (linea semicircularis / Douglas's line) marks this transition — a surgically important landmark for TEP hernia repair and rectus sheath hematoma.

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POSTERIOR ABDOMINAL WALL — Layers

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NERVE SUPPLY OF ANTERIOR ABDOMINAL WALL

McBurney's point (appendix) — T10 dermatome
Umbilicus — T10 dermatome (landmark for spinal block level)

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BLOOD SUPPLY

The inferior epigastric artery is the medial boundary of the deep inguinal ring (lateral to Hesselbach's triangle). Critical landmark in laparoscopic inguinal hernia repair.

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SURGICAL INCISIONS & LAYERS ENCOUNTERED

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QUICK REVISION

Layers at the Camera Port in Laparoscopic Cholecystectomy

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Why the Umbilicus?

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Layers Traversed at the Umbilical Camera Port

(Superficial → Deep)

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Key Anatomical Points

• No muscle layer is cut at the umbilicus — the rectus muscles lie lateral; only the linea alba (aponeurosis) is incised
• The skin at the umbilicus is directly fused to the linea alba — hence it is everted and grasped at the cicatrix to get closest to the fascia
• The decussation of fibres just above the linea alba junction is the fascial layer that is incised
• Below the umbilicus: the posterior rectus sheath is absent (below arcuate line) — only transversalis fascia + peritoneum lie deep to the muscles
• The inferior epigastric vessels lie lateral — safe at the midline umbilical entry

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Two Techniques of Umbilical Entry

1. Veress Needle (Closed Technique)

• 1st pop = Linea alba / fascia
• 2nd pop = Peritoneum Then insufflate → blind trocar insertion

2. Hasson's Open Technique (Preferred, Safer)

1. Evert umbilical cicatrix with toothed forceps
2. Dissect down to expose decussation of fibres above linea alba
3. 5 mm vertical incision through fascia only
4. Blunt haemostat pushed through preperitoneal fat + peritoneum — "pop" felt
5. Blunt-tipped 10/12 mm trocar inserted under direct vision
6. Camera confirms intraperitoneal placement → CO₂ insufflation begins

Hasson's technique is preferred in obese patients, previous abdominal surgeries, and beginners — avoids risk of vascular/bowel injury from blind Veress needle insertion.

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Summary — Layers at a Glance

SKIN
  ↓
Subcutaneous fat (Camper's fascia)
  ↓
Scarpa's fascia
  ↓
Umbilical cicatrix / stalk
  ↓
LINEA ALBA ← only fascial layer incised (no muscle here)
  ↓
Extraperitoneal fat
  ↓
PARIETAL PERITONEUM ← "pop"
  ↓
PERITONEAL CAVITY ✓

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Complications Related to Port Insertion at This Site

Always close fascial defects ≥10 mm at the umbilical port — risk of port-site hernia is significant if linea alba is not sutured.

Ports of Laparoscopic Cholecystectomy

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Standard 4-Port Technique (American/French)

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Port Details — One by One

PORT 1 — Camera Port (Primary Port)

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PORT 2 — Epigastric Port (Surgeon's Right Hand)

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PORT 3 — Right Mid-Abdomen Port (Surgeon's Left Hand / Retraction)

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PORT 4 — Right Anterior Axillary Line Port (Assistant's Port)

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Summary Table

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Port Placement Principles (Bailey & Love, p. 124)

1. All secondary ports inserted under direct vision — never blind
2. Trocars always inserted perpendicular to abdominal wall
3. Non-midline ports placed lateral to rectus sheath (mid-clavicular line) to avoid inferior epigastric vessels
4. Use smallest diameter trocar possible — less pain, less hernia risk
5. All ports >5 mm require fascial closure to prevent port-site hernia
6. Remove all ports under direct vision — check for port-site bleeding

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American vs French Technique

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Alternative Techniques

3-Port Technique

• Port 4 (assistant's port) omitted
• Surgeon provides retraction through Port 3
• Suitable for: thin patients, experienced surgeons, non-complicated gallbladders

Single Incision Laparoscopic Surgery (SILS)

• All ports through one umbilical incision using a multi-channel port
• Better cosmesis ("scarless")
• Technical difficulty higher; longer operative time
• Not standard of care

Robotic Cholecystectomy

• 4 ports (3 robotic arms + 1 assistant)
• Placed more superiorly to accommodate robotic arm geometry

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Critical View of Safety (CVS) — Why Port Positions Matter

• Port 3 retracts Hartmann's pouch laterally → opens hepatocystic triangle
• Port 4 retracts fundus upward → stretches cystic duct
• Port 2 dissects Calot's triangle from epigastric approach at correct angle

CVS requires: (1) Hepatocystic triangle cleared of fat/fibrotic tissue, (2) Lower gallbladder dissected off liver bed, (3) Only two structures entering gallbladder visible — before any clipping.

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Port-Site Complications

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SAGE Guidelines — Safe Cholecystectomy

Bile duct injury occurs in 0.3–0.6% of laparoscopic cholecystectomies — the most feared complication. SAGES SAFE guidelines were created to systematically reduce this.

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The SAGES Safe Cholecystectomy Program — 6 Strategies

"The Fundamental Principles of Safe Laparoscopic Cholecystectomy"

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1. ACHIEVE THE CRITICAL VIEW OF SAFETY (CVS)

CVS was described by Strasberg et al. (1995) — the gold standard before clipping any structure.

• CVS must be achieved from both anterior and posterior views
• If CVS cannot be achieved → do NOT clip → move to bail-out strategies
• Document CVS with a photograph intraoperatively

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2. KNOW THE HEPATOCYSTIC TRIANGLE ANATOMY & ITS VARIATIONS

• Superiorly — inferior surface of liver
• Medially — common hepatic duct
• Laterally — cystic duct

Important Anatomical Variations to Know:

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3. RECOGNIZE THE INFUNDIBULAR TECHNIQUE IS UNRELIABLE

• In inflammation/fibrosis, the CBD can be tented up and mistaken for the cystic duct
• The parallel course variant of the cystic duct running alongside the CBD is especially treacherous
• SAGES explicitly states: the infundibular technique alone should NOT be used — CVS must be achieved

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4. IF IN DOUBT — STOP AND OBTAIN A CHOLANGIOGRAM / BAIL OUT

Bail-out Strategies (in order of preference):

The most important bail-out is conversion to open — this is NOT a failure; it is a safe, deliberate decision.

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5. KNOW WHEN AND HOW TO OBTAIN HELP

• Involve a more experienced colleague intraoperatively if uncertain
• Refer to an HPB (Hepatopancreatobiliary) surgeon if BDI is suspected
• Do not attempt repair of a bile duct injury if you are not trained in biliary reconstruction — premature repair worsens outcomes
• Intraoperative recognition of BDI → immediate referral to HPB center

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6. AVOID CLASSIC BILE DUCT INJURY MECHANISMS

The "Visual Illusion" — Most Common Cause of BDI:

• Excessive cephalad traction on the gallbladder aligns the CBD with the cystic duct
• Creates a false impression of a "cystic duct" that is actually the CBD
• Compounded by failure to achieve CVS

Strasberg Classification of BDI:

Type E injuries (CBD transection) are the most devastating — require Roux-en-Y hepaticojejunostomy.

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SAGES SAFE CHOLECYSTECTOMY — The 5 Pillars (Simplified for Exam)

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Critical View of Safety vs Other Methods

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"Difficult Cholecystectomy" — When to Anticipate Problems

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Subtotal Cholecystectomy — The Ultimate Bail-Out

Fenestrating type has higher bile leak rate but is safer in hostile abdomen. Both are safer than risking BDI.

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Quick Revision — SAGE in One Line Each

• S — Stop if unsafe; Subtotal if Calot's hostile
• A — Achieve CVS (all 3 criteria) before clipping
• G — Get help / Get a cholangiogram when in doubt
• E — Examine anatomy carefully; know variants

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Bottom line: The single most important safety measure in laparoscopic cholecystectomy is achieving and documenting the Critical View of Safety before placing any clip. When in doubt — bail out.

Carter-Thomason Suture Passer

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What Is It?

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Indications

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Components of the Carter-Thomason Device

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How It Works — Step by Step

Principle:

Steps:

• Pneumoperitoneum maintained; 30° camera observing from adjacent port
• Trocar to be closed still in situ (or partially withdrawn)

• Carter-Thomason guide inserted through/alongside the trocar into peritoneal cavity
• Suture passer needle advanced through one diagonal channel (e.g., 1:30 o'clock position)
• Needle tip seen inside peritoneal cavity by camera
• Free end of suture loaded into the needle hook and pulled back through the channel — suture now passes through fascia on one side

• Guide rotated 180° (to 7:30 o'clock position — opposite side of defect)
• Suture passer advanced through second channel
• Loop of the same suture captured and pulled back through — suture now passes through fascia on both sides of the defect

• Trocar removed while maintaining suture ends
• Both ends of the suture now exit through the skin on either side

• Fascia is pulled together as suture is tied
• Creates a figure-of-8 closure of the full fascial defect
• Skin closed separately with absorbable subcuticular suture or skin glue

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Types of Suture Patterns Achieved

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Advantages

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Disadvantages / Complications

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Alternatives to Carter-Thomason

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Important Rules for Port-Site Fascial Closure

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Port-Site Hernia — Why It Matters

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Quick Summary

Carter-Thomason Suture Passer
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  Guided cannula → peritoneal cavity
         ↓
  Suture passed through fascia
  (both sides of trocar defect)
  under direct laparoscopic vision
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  Trocar removed
         ↓
  Figure-of-8 fascial closure tied
         ↓
  Port-site hernia PREVENTED

Key teaching point: The Carter-Thomason device converts a previously blind and technically difficult fascial closure into a safe, direct-vision, reproducible procedure — essential for all laparoscopic ports ≥10 mm.