Fascial Closure in Midline Laparotomy

Fischer's Mastery of Surgery, 8th ed.

Anatomical Considerations

The midline incision divides the linea alba - the avascular fibrous fusion of the bilateral anterior and posterior rectus sheaths. When closing, the primary goal is to approximate only the linea alba (fascia/aponeurosis) without incorporating fat or muscle in each stitch.

The oblique abdominal muscles generate forces perpendicular to the healing linea alba, making it biomechanically vulnerable. Long-term incisional hernia rates exceed 20% after midline laparotomy.

Key principle: Fatty and muscular tissues incorporated in a stitch become ischemic under suture tension, undergo necrosis, create suture slack, and allow fascial edge separation - the primary mechanism of hernia formation.

Hernia formation mechanism based on suture bite size - large bites incorporating fat and muscle (A/B) cause suture slack vs. small fascial-only bites (C/D) maintaining apposition

Large tissue bites incorporating fat and muscle (A) lead to suture slack and fascial gaps (B) as tissues necrose. Small bites of only fascia (C) result in minimal necrosis and maintained apposition (D).

Layers Closed (and Not Closed)

Layer	Action	Rationale
Peritoneum	Not closed separately	Adds no strength; unnecessary
Linea alba (fascia)	Closed - primary layer	Only layer that matters for strength
Subcutaneous fat / Scarpa fascia	Closed with antimicrobial suture in obese patients	Reduces SSI in high-BMI patients; does not affect hernia rate
Skin	Closed as appropriate; NPWT or delayed closure in septic/contaminated wounds	Wound infection increases hernia risk

Drains and ostomies should never exit through the midline incision, as they predispose to infection and weaken the closure.

Suture Material

Type

A synthetic monofilament slowly absorbable suture is the evidence-based choice:

Monofilament sutures are acapillary - they do not wick bacteria, unlike braided multifilament sutures.
Slow absorption (e.g., polydioxanone/PDS, Maxon, Monoplus) is essential because fascial healing takes over a year; these sutures retain >50% tensile strength at 6 weeks and absorb after 6-8 months.
Fast absorbable sutures (e.g., Vicryl) retain only 25% strength at 4 weeks - the fascia has not healed sufficiently, risking dehiscence, evisceration, and hernia.
Nonabsorbable sutures (polypropylene, polyester) remain an option but carry risk of long-term suture sinuses and infection.

Gauge

USP 2-0 on a small (20-mm) taper-tip needle (SH needle) for small-bite technique. The small needle arc helps restrict each bite to fascia only.

Suturing Technique

Continuous vs. Interrupted

Continuous suture is the standard for elective midline closure - faster, fewer knots, less foreign material.
Interrupted suture may be preferred in: thin/frail fascia, closure under tension, or emergency laparotomy settings - failure of one suture does not cause failure of the entire line. A 2026 meta-analysis (25 RCTs, n=3,548) found interrupted closure significantly reduced wound dehiscence (RR 0.47) and shortened hospital stay in emergency laparotomy. [PMID 41761330]
Retention sutures have largely been abandoned - little evidence supports their use.

The Small Bite Technique (Evidence-Based Gold Standard)

The cornerstone of modern fascial closure is the small bite technique achieving a Suture Length : Wound Length (SL:WL) ratio >4.

The SL:WL Ratio

Each stitch should be placed:

5-8 mm back from the fascial edge
5 mm apart (advancement between bites)

This produces a ratio of suture used vs. wound length of at least 4:1, distributing force across many stitches and reducing pull-out risk.

A 2025 meta-analysis (7 RCTs, n=2,299) confirmed small bites vs. large bites:

Reduced ventral incisional hernia by 54% (RR 0.46)
Reduced SSI (RR 0.73)
Shortened length of stay [PMID 40354104]

Step-by-Step Technique

Four-panel intraoperative demonstration of small bite technique: (A) wound length measured, (B) suture started with half-blood knot, (C) running 5mm bites completed, (D) remaining suture measured to confirm SL:WL >4

Measure the wound length and multiply by 4 to calculate the minimum suture length required.
Select a 2-0 slowly absorbable monofilament (PDS) on an SH needle of sufficient length. Record initial suture length.
Pass the suture through tissue just above the apex of the fascial defect and secure with a half-blood knot (tail kept short to minimize suture loss). Measure and subtract the discarded tail.
Run the closure with 5 mm bites back from the fascial edge, 5 mm apart, incorporating only the linea alba - no fat, no muscle.
Approximate the fascial edges without tension. Applying tension risks suture pull-out with small bites.
At the end, secure with an Aberdeen knot (same type used to finish subcuticular closures). Measure and subtract the remaining tail.
Calculate achieved SL:WL ratio: (original length - tail 1 - tail 2) / wound length. If <4, remove the suture and repeat.
If the wound is too long for one suture, use two sutures (one from each end), each secured with Aberdeen knots adjacent to each other - do not tie the sutures together (this would reduce burst strength).
Document the wound length, total suture used, and achieved SL:WL ratio in the operative note.

Knot Details

Half-blood knot (starting knot): Three loops of the short tail around the long end, tail passed up through all three loops, then the long end pulled to cinch. Minimizes wasted suture.
Aberdeen knot (finishing knot): The free end is passed through the loop three times creating successive new loops; on the fourth pass the free end is pulled all the way through, tightening the knot.

Prophylactic Mesh Augmentation (PMA)

In high-risk patients (e.g., open AAA repair, morbid obesity, active smokers, collagen disorders), PMA may be considered after primary fascial closure.

Mesh can be placed in intraperitoneal, preperitoneal, retrorectus, or onlay planes.
Onlay and preperitoneal positions carry higher seroma risk.
PMA is contraindicated in: patients requiring future laparotomy (e.g., stoma reversal), pregnancy, mesh allergy, and is relatively contraindicated in contaminated/infected wounds.
PMA is not used for incisional hernia repair - it is a prophylactic adjunct to primary closure only.

Summary of Evidence-Based Principles

Parameter	Recommendation
Suture type	Monofilament slowly absorbable (PDS)
Suture gauge	USP 2-0
Needle	20 mm taper tip (SH)
Technique	Continuous running (elective); interrupted considered in emergency/high tension
Bite depth	5-8 mm from fascial edge, fascia only
Bite spacing	5 mm between stitches
SL:WL ratio	Must achieve >4:1
Peritoneum	Do not close separately
Subcutaneous	Close with antimicrobial suture in obese patients
Drains/ostomies	Never through midline incision

Sources:

Fischer's Mastery of Surgery, 8th ed. - Chapter on Fascial Closure in Midline Laparotomy
Alrashidi et al. (2025) - Small vs. large bites meta-analysis, 7 RCTs, n=2,299 [PMID 40354104]
Alharran et al. (2026) - Interrupted vs. continuous in emergency laparotomy, 25 RCTs, n=3,548 [PMID 41761330]

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