How to mark the incision for a Limberg flap procedure in a young adult patient with a history of recurrent pilonidal sinus infections?

Limberg Flap Incision Marking for Pilonidal Sinus

Mark a rhomboid excision with 60° and 120° angles centered over the sinus, extending the inferior apex 1-2 cm lateral to the midline, then create the flap by extending one side of the rhomboid at the same angle and length to form the transposition flap from the gluteal region.

Preoperative Marking Technique

Step 1: Define the Rhomboid Excision

• Mark the primary rhomboid shape with all sides equal in length, incorporating all sinus openings and tracts with adequate margins 1, 2
• Create angles of 60° and 120° at alternating corners to form the classic rhomboid geometry 1, 3
• Ensure the long axis of the rhomboid runs parallel to the natal cleft, with adequate tissue margins around all visible sinus openings 4, 2

Step 2: Asymmetric Modification (Critical for Reducing Recurrence)

• Position the inferior (lower) apex of the rhomboid 1-2 cm lateral to the midline rather than centered over the natal cleft 5
• This lateralization modification significantly reduces recurrence rates (from 7.5% to 0% in comparative studies) by moving the suture line away from the midline 5
• The superior apex can remain closer to midline, creating an asymmetric rhomboid that still maintains equal side lengths 5

Step 3: Mark the Limberg Flap

• Extend one side of the rhomboid (typically the lateral side) by drawing a line of equal length to the rhomboid sides, maintaining the same 60° angle 1, 2
• From the end of this extension, draw another line of equal length parallel to the opposite side of the rhomboid to complete the flap outline 3, 2
• The flap should be designed from the gluteal region to ensure adequate fasciocutaneous tissue for tension-free closure 3, 4

Key Anatomical Landmarks

• Natal cleft: The primary landmark - the inferior apex should be deliberately offset 1-2 cm lateral to this 5
• Sacrococcygeal region: The rhomboid should encompass the entire disease area in this region 4, 2
• Gluteal fascia: Ensure the flap extends into healthy gluteal tissue with intact fasciocutaneous layers 3

Critical Technical Points

Sizing Considerations

• All four sides of the rhomboid must be equal length for proper flap geometry 1, 2
• The flap dimensions automatically match the defect when constructed with equal-length extensions 2
• Adequate excision margins around all sinus tracts are essential - err on the side of wider excision 1, 5

Common Pitfalls to Avoid

• Do not center the rhomboid symmetrically over the midline - this increases recurrence risk by placing the suture line directly in the natal cleft 5
• Avoid making the angles too acute or obtuse, as this compromises flap geometry and increases tension 1
• Do not underestimate the extent of sinus tracts - mark for en bloc excision of all diseased tissue 3, 2

Expected Outcomes with Proper Technique

• Recurrence rates of 1.3-4.8% with standard technique, reduced to 0% with lateralization modification 1, 2, 5
• Hospital stay of 2-4 days with return to full activity in 8-25 days 1, 2, 5
• Wound infection rates of 0.8-2.7% when proper technique is employed 2, 5
• The modified lateralization technique shows statistically significant reduction in recurrence compared to classical midline-centered approach (P = 0.004) 5