Anatomical rationale and sheath structure
The wall of the digestive tract is formed by four main layers: the mucosa, submucosa, muscular layer, and serosa (or adventitia in the esophagus). In operative surgery, this structure is conventionally considered as two sheaths:
- Internal sheath — combines the mucosa and submucosa.
- External sheath — includes the muscular layer and serosa.
Between these sheaths lies loose connective tissue, allowing the layers to slide relative to each other. This exact property underlies the classical double-row suture technique, where the first row passes through all layers, and the second (external) row involves only the elements of the external sheath, ensuring airtightness.
Classification of intestinal sutures
All surgical connections on hollow organs are divided into several groups according to their purpose and execution technique:
- Penetrating (internal, contaminated) sutures — pass through all layers of the organ wall. These include the continuous running catgut suture, the inverting Schmieden furrier's suture (when the walls are inverted inward with their serosal surfaces), and individual interrupted sutures with knots tied into the intestinal lumen.
- Aseptic (external) sutures — do not penetrate into the lumen of the hollow organ. These include the seromuscular suture, the purse-string suture (used for burying the stump of the appendix or duodenum), and the additional Z-suture.
- Hemostatic sutures — created specifically to stop bleeding from the transected wall. Basic functions are performed by Schmieden and running sutures, while for complex areas, the Reverdin-Multanovsky loop suture or the "lock-stitch" on the gastric stump is used.
Technique of double-row anastomosis
The end-to-end connection is a classic example of applying a double-row suture in practice:
- The proximal and distal ends of the intestine are brought together by their posterior surfaces.
- The posterior row of seromuscular interrupted sutures is applied (0.7–1.0 cm setback, 0.5 cm interval), leaving the end threads as retention stays.
- The intestine is transected under clamps, and the lumen is formed.
- The posterior and anterior lips are sutured using a continuous running suture or Schmieden suture (internal penetrating row).
- Instruments and gloves are thoroughly changed, after which the anterior seromuscular row of interrupted sutures is applied over the first row.
Mechanical suture in modern surgery
Instead of manual labor, surgeons actively use stapling devices. Their main advantages are speed of application, ease of use, absolute sterility, and lack of hygroscopicity.
- UKZhA-60 — a device for suturing the gastric stump and forming a gastrointestinal anastomosis.
- KTsy — a device for applying a circular suture on the large intestine.
- UKL-60 and UKL-40 — universal suturing devices also used in abdominal surgery.
- Miniature tantalum staples are used as the fastening material in the devices.
Briefly: answers to topical questions
Which types of intestinal sutures are classified as single-row?
Single-row intestinal sutures include the single-row penetrating suture. The walls of the segments being sutured are connected by individual interrupted sutures, in which the ligature passes through all layers of the wall (from the inside out and outside in). The knot is tied on the mucosal side so that it faces the intestinal lumen.
Characteristics of the suture:
- Fine scar — forms at the site of suturing;
- Rapid epithelization — accelerated restoration of the mucous membrane;
- Absence of microabscesses — does not create conditions for their formation within the wall.
The suture requires frequent stitch placement for tightness and is less reliable for hemostasis.
What are the named modifications of the continuous everting intestinal suture?
The named modification of the continuous everting intestinal suture described in the literature is the Schmieden suture (furrier's suture).
Technical features:
- Thread direction — always from inside out: from the mucosa to the serosa;
- Everting effect — when tightened, the walls are inverted;
- Apposition — the sutured edges come into contact with their serous surfaces.
The Schmieden suture is used when suturing the anterior lips of an anastomosis as a variant of the inner row of sutures.
Inner layer — mucosa and submucosa (full-thickness), outer layer — muscle and serosa (for airtightness only). Catgut is used for the infected full-thickness row, silk/non-absorbable suture for the aseptic outer row.
Class and exam questions
What are the basic requirements for intestinal sutures?
Strict adherence to asepsis, meticulous hemostasis, minimal tissue trauma (especially to the mucosa and submucosa), and ensuring reliable airtightness.
What is the difference between the Schmieden suture and a conventional running whipstitch?
In the Schmieden suture, the thread is always passed from inside out, which causes the organ walls to invert into the lumen and appose their serous membranes. A conventional running whipstitch passes both from inside out and from outside in.
How many rows of sutures are applied to the esophagus and large intestine?
Three-row sutures are traditionally applied to these anatomical regions to ensure maximum airtightness and reliable hemostasis.
What is the purpose of a purse-string suture?
A purse-string suture is used for burying the appendiceal stump, the duodenal stump, and for closing small stab wounds of hollow organs.
What else to study on this topic
- Common types of GI surgeries: enterotomy, stoma creation, resection, and ectomy
- Comparison of single-layer full-thickness and multi-layer sutures
- Technique of the Reverdin-Multanovsky (looping) suture
- Indications and features of the "line" suture in gastric resection
- Advantages and disadvantages of manual intestinal suture compared to mechanical
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