Suturing Techniques

 Stitching a wound can be accomplished using a variety of approaches. Only the most widely used methods are discussed.

Factors to be considered on specific material and technique

1. Type of tissue

2. Type of wound

3. Time available

4. Aesthetic available

5. Functional needs

6. Likely tension on the wounds

7. Expected time for tissue healing

 

Simple Interrupted Suture

Suturing a wound with a simple interrupted suture ('basic loop') is the most common approach. This is the most basic wound closure design. The suture is looped once through each side of the wound and then secured above the surface in a knot. Several of these ties are created throughout the length of the wound, resulting in a collection of separate sutures that hold the tissue borders together. Internal suturing of tissue layers is routinely done with the same approach.

On one side, the needle penetrates the surface 2–3 mm distant from the wound edge and enters the subcutaneous tissue. The needle's curvature is then used to send it through to the opposite side's subcutaneous tissue. After that, the needle exits through the surface. The initial and final tags are then put in a knot outside of the tissues. As a result, the internal configuration of the tissue is in the form of a loop. If the depths of the wounds are asymmetrical, the needle should go deeper on the lower side while remaining superficial on the upper side. This will aid in the correction of the depth disparity and the levelling of the surface.

This method is simple to understand and apply. This suture has a high tensile strength and a low risk of oedema or poor circulation in the wound. Depending on the wound parameters, this approach allows for several design changes. Because the wound edges are held together by a sequence of sutures, even if one fails, the others may be strong enough to keep the wound edges together.

The main disadvantage of this suturing procedure is the significant risk of 'rail-road track' scars generated by epithelial ingrowth into the suture tracks. Due to tissue rigidity during healing, 'wound inversion' (depression of the surface at the wound site) is also a possibility. Inversion can be avoided by making the suture configuration inside the tissues 'flask-shaped,' and by moving the needle laterally away from the incision within the tissues. When opposed to continuous suturing approaches, the interrupted method takes longer since it necessitates the tying of many more knots.

Simple Buried Suture

The buried suture is a variation of the simple interrupted suture that is used to stitch the inner (deeper) layers of tissue. The sole difference is that the knot is placed deeper in the tissues, away from the surface, than the suture loop. In essence, this is a basic interrupted suture that has been reversed.

Fine forceps or hooks are used to reflect the wound edge first. On one side, the needle is placed into the dermis's underside. The needle then continues along its curvature, exiting in the wound edge that is closer to the initial bite. The needle then pierces the second side's dermis wound edge (near the surface), follows the same path as the first side, and emerges at a deeper point that corresponds to the first bite. Even though the tie is tied externally, as it is tightened, the knot becomes buried deep into the tissues.

Suturing the inner tissue layers before the surface closure is particularly useful with this procedure. The knot is buried deep enough that it does not obstruct the closure of the superficial layers. This feature comes in handy when it comes to closing cutaneous face wounds.

This suture has been found to have two fundamental flaws. One is skin dimpling, which occurs when the suture arc accidentally passes through the epidermis. Another issue is the possibility of wound inversion. To alleviate this problem, small changes such as a set-back dermal buried suture or a vertical mattress buried suture can be used. These changes aim to make the bridging suture segments pass deeper, resulting in wound eversion.

Vertical Mattress Suture

The vertical mattress suture resembles basic interrupted sutures in appearance, but it has an additional suture bridge towards the incision edge. This suturing technique, also known as Donati Suture or 'far-far, near-near' suture, is the most commonly employed to obtain wound eversion. This type of suture is commonly used in abdominal and limb surgery.

The needle is inserted far away from the wound edge (approximately 6 mm), then into the deeper tissue to the opposite side, emerging at a similar distance from the edge. On the second side, the needle is reinserted at a place closer (2–3 mm) to the wound edge. It is then twisted superficially through the tissues before exiting at a corresponding near position on the other side. As a result, the wound has two bridgings, one deep in the tissues and the other superficial and closer to the wound edge. As a result, both thread tags are now on one side of the wound. They are delicately connected together.

The primary benefit of this suture is the wound eversion that results. This eversion is thought to compensate for the anticipated contracture near the wound's edge. The suture's binding strength is increased since it crosses the wound twice. Another evident benefit is the elimination of dead space. The suture thread does not cross through the wound edge on the surface, so track markings are unlikely.

On the other hand, this suture nearly never achieves delicate wound edge approximation. Excessive tightening might result in over-constriction and, in certain cases, raw skin exposure. For improved results, it may be necessary to apply additional interrupted sutures.

In a buried suture situation, the vertical mattress concept can be applied by ensuring that the more superficial suture thread is returned to the first side in a direction parallel to the first, deeper suture bridge. As a result, wound eversion will be improved.

Simple Continuous Suture

Simple continuous suture (also known as 'running loop' or'standard running suture') is an effective way to close minor wounds quickly. It ensures that tension is distributed evenly over the wound span. It combines several of the advantages of basic interrupted sutures with the added bonus of a faster finish.

The method is extremely straightforward. The initial step is similar to that of a basic interrupted suture. The first knot serves as an anchor for the subsequent running line. The tags aren't clipped, and the longer tag (with the needle) is utilised to complete the loops. A few millimetres away from the original piercing, the needle is reinserted into the tissues. The needle then travels through the tissues in a direction parallel to the first loop, followed by the thread. It is not tied until it has exited the second loop. Instead, the loop is tightened, and the thread is crossed over the wound obliquely.enters the tissue surface for a second time, a few centimetres apart from the first piercing. This method is repeated until the other end of the wound has been reached. The thread is only partially drawn through the tissues as the last loop is pulled through, leaving some loose thread on the other side. For the final knot, the suture is connected to this slack thread. As a result, the suture material loops repeatedly across the wound, with only two knots—one at each end.

The obvious advantages of this approach are the speed with which sutures are placed and the ease with which many knots are avoided. In addition, if the tissue wells up in one location, the remaining suture can provide some compensating slack.

The main disadvantage is that the entire suture line's integrity is vested in just two knots. Any break in the suture, no matter where it occurs, causes the entire line to untie. Because the loops are sequential, fine-tuning the architecture for each loop is impossible. Also, because all loops have the same tension, the parts of the wound with the most tension, usually the middle part, may gape.

Locking Continuous Suture

This is a version of the simple continuous suture technique used to close wounds on the skin's surface. Before constructing the next loop, each loop of the continuous suture is 'locked' on itself. This is the most common continuous suturing technique, which is used to close wounds over long periods of time. After the interior tissue layers have been closed, this approach, like other superficial continuous sutures, is widely employed as a surface layer.

The initial loop is passed and the knot is tied in the same way as the simple continuous approach. The suture is not tightened immediately after the second loop has passed through the tissues and exited. The needle, as well as the leading thread, are designed to pass through the previous loop. The suture is tightened after this 'lock' and then passed into the tissues for the third loop. This strain should be maintained by the assistance till the following loop is passed. This procedure is performed for each subsequent loop in the line.

The locking aids in the proper anatomic alignment of the tissues perpendicular to the incision. Because of the stress on the tissues, there is an extra haemostatic impact. All of the loops are kept at the same level of tension. At the same time, the running locks disconnect the different loops' tension from one another to some extent. Individual control of stress depending on the site can thus be achieved to some extent.

The fundamental problem of simple continuous sutures is that they are only dependent on two knots, and there is a risk of complete loss of suture integrity if one of them breaks at any moment. If the locks are overly tight, the underlying tissues' vascular integrity may be compromised.

Subcuticular Suture

This is a surface wound closure that is mostly buried, continuous, and epidermal. Suture ends emerge a few millimeters from the wound corner. After the deeper tissues and dermis have been adequately fastened with absorbable sutures, the subcuticular suture is used. It is often used as a facial cosmetic suture.

The suture is usually thin (size 5–0 or 6–0) and absorbable or non-absorbable. The needle is inserted 2–5 mm from the apex of the wound at one end. It is inserted into the wound along the curvature and exits in the interior, close to the apex. The needle is then re-inserted into the dermis on each side of the wound's border walls. Following that, it goes horizontally parallel to the surface, following the needle curve to emerge a little distance into the wound interior. The same procedure is then carried out on the opposite side of the wound. This operation is repeated until the needle pierces the other end of the wound, at which point it is removed. The apex at the far end, and to emerge from the surface The final phase is a mirror image of the first two. After that, each of the suture tags on both sides is linked to itself independently. Alternatively, adhesive strips, surgical tape, or tissue glue can be used to secure the tags.

The most significant benefit of this method is the much reduced likelihood of scarring. A further surface suturing is not required due to the tight closeness attained in the dermis region. The suture tension is equally distributed throughout the length of the stitch and is placed centrally across the wound. Also, if the suture material needs to stay in place for a lengthy time, this procedure is ideal.

The subcuticular suture, on the other hand, takes longer to apply. Leaving a substantial amount of foreign material in place raises the risk of infection and foreign body reaction. If non-absorbable material is utilised, there is a chance that the suture track will remain long and thin after removal.To avoid cutaneous visibility, an undyed suture should be utilised if absorbable material is employed. If you use the wrong technique, you may end up with little areas of exposed raw skin that need to be addressed with extra surface sutures.

Three-point Suture

This technique, also called as a 'tip stitch' or a 'half-buried horizontal mattress suture,' is used to manage a situation in which three ends of tissue must be sutured together. This condition arises in maxillofacial surgery while mending V-shaped lacerations and sealing flaps with sharp corners (such as the triangular flap at the vermilion border for cleft lip repair)

A laceration that needs Three-point suturing

Only after the flaps have been pulled into position using buried dermal sutures is this suture used. The surface suture thread is 6–0 for the face and 3–0 for the scalp. The needle is first put into one of the wound's non-flap sides. It exits the wound on the inner side, following the needle curvature. The flap tip's superficial dermis is the next tissue to be inserted. The needle then goes horizontally and emerges on the other side of the flap tip through the dermis. It re-enters the dermis of the non-flap side on the other side after releasing from the flap tip and emerges through the skin at a place comparable to the first entry. The tags are then knotted together.

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