8 Suturing: Basic Skills and Techniques

8.1 Loading the Needle in the Needle Holder

Properly loading the needle in the needle holder ( Fig. 8.1) may seem a trivial point, but improper loading ( Fig. 8.2) may introduce potential problems that are both significant and avoidable. The scrub nurse will often be the person to initially load the needle into the needle holder, but in many cases the surgeon will need to reload it multiple times on the surgical field as the suturing proceeds.

The first step in loading the needle into the needle holder is obtaining a stable grasp of the needle. This can be done with the fingertips, a smooth forceps, or a second needle holder. Handling the needle with the fingertips rather than instruments is generally the fastest way to proceed but must be done with caution to avoid injury. Reaching directly for the needle is to be avoided, as this is perhaps the most certain way to guarantee an injury. Instead, it is very safe to hold the thread, away from the needle, between the thumb and index finger, and then use the other hand to draw the needle backward until the swage rests against the fingertips ( Video 8.1). At that point, the needle is well controlled and may be loaded into the needle holder in the correct orientation for the intended pass. Pulling the swaged end of the needle back toward the hand will not cause an injury because there is no penetrating forward force applied to the needle’s tip.

When operating under a microscope, a needle may be loaded into the needle holder using two techniques. A smooth instrument, such as a tying forceps, can be used to dangle the needle by its thread onto the ocular surface, allowing it to then be grasped by the needle holder ( Video 8.2). When this technique is used it is helpful if the ocular surface is thoroughly wetted with balanced salt solution. The surface tension of the fluid layer helps hold and stabilize the needle body in position. Alternatively, the needle can be held directly with smooth forceps and then grasped by the needle holder in the appropriate orientation and position. It may be easier to perform these maneuvers under lower magnification, as this permits a longer and wider depth of field.

When using a needle holder with curved jaws, it is important to load the needle with the tip extending from the convex surface and the swage extending from the concave surface ( Video 8.3; Fig. 8.1). The needle should be loaded with the tip pointing in the direction of the intended pass, whether or not the surgeon will make the pass in a forehanded or backhanded manner. For an intended backhand pass, the needle will be loaded in the same orientation as it would be for a forehand pass by the opposite hand. For example, a forehand pass with the left hand is loaded in the same orientation as a backhand pass with the right hand ( Video 8.3).

Fig. 8.1 Proper needle loading. The needle is grasped near the tip of the needle holder jaws, between one-half and two-thirds of the distance from the needle tip to the swage. When a needle holder with curved jaws is used, the curve of the jaws (concave side) points toward the needle’s swage.

Fig. 8.2 Improper needle loading. (a) Loading the needle on the swage. (b) Loading too close to the needle tip. (c) Loading too far back on the needle body. (d) Loading too far back in the jaws of the needle holder.

Video 8.1 Controlling the needle safely in preparation for loading a needle holder. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v001&t=video

Video 8.2 Dangling the needle to reload the needle holder. This technique is useful for loading under an operating microscope. https://www.thieme.de/de/q. htm?p=opn/tp/300500101/9781626237308_c008_v002&t=video

Video 8.3 A forehand versus backhand needle pass. Note that a needle loaded for a backhand pass with one hand is oriented the same way in the needle holder as for a forehand pass with the opposite hand. https://www.thieme.de/de/q.htm?p=opn/tp/300500101 / 9781626237308_c008_v003&t=video

Video 8.4 The stability of the needle is affected by the position on the needle body in which it is held. The further back on the needle body that it is loaded, the greater the torque experienced at the tip, and the less stable the control. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v004&t=video

Another important concept to understand is that the closer the needle holder jaws are to the tip of the needle the better will be the control of the tip. Small deviations are magnified as the distance to the target increases. Those who play the game of golf understand this concept particularly well. On the other hand, the distance from the tip of the needle to the needle holder determines the distance the needle can travel through tissue without re-grasping. Therefore, the needle should be loaded far enough back from the tip to achieve the necessary length of the pass, but no further. This will optimize the balance between control of the needle and length of the pass.

A general guideline is to grasp the needle between one-half and two-thirds of the distance back from the needle tip toward the swage, with the needle body perpendicular to the needle holder’s jaws( Fig. 8.1). The further the needle is loaded back toward its swage the greater the torque experienced at the tip. In addition to the control issues mentioned above, greater torque at the tip also increases the potential for bending the needle or allowing the needle to unintentionally shift direction during the pass ( Video 8.4). The needle should never be loaded on the swage itself( Fig. 8.2a), as this is an unstable position, and predisposes the needle to rotate in an uncontrolled fashion during the pass. The needle should be loaded close to the tips of the needle holder’s jaws ( Fig. 8.1), rather than back near the hinge ( Fig. 8.2d). Loading the needle too far posteriorly into the jaws may cause the holder’s tips to interfere with passing the needle, particularly when exposure is limited.

8.2 Grasping and Holding the Tissue

One of the key concepts to keep in mind when holding and stabilizing tissue in preparation for passing a suture needle is to hold the tissue close to the spot where the needle will be passed and in such a manner as to easily see the intended entry point at all times. The rationale for maintaining clear visualization is self-evident, but requires proper positioning of the hands ( Video 8.5).

Grasping the tissue close to the intended entry point greatly improves control and precision. If there is a freely mobile tissue edge, as is often the case with a tissue flap, stabilization will be maximized if the tissue is held on the side of the free edge, while passing the needle on the anchored side ( Video 8.6). To optimize visualization and tissue stabilization, as well as contend with various anatomic constraints, it may be helpful or even necessary to alter which hand holds the tissue and which hand passes the suture.

The principles of optimal wound healing, anatomic integrity, and cosmesis that were discussed in Chapter 3 and Chapter 4 should be kept in mind when planning and executing wound closure. For skin closures, these principles require that the tension on the wound edges be minimized, and the edges slightly everted, in order to avoid creating a depression on the surface of the healed wound following cicatrization. Maintaining anatomic integrity requires that identical layers are carefully reapproximated, and extraneous tissues are not inadvertently incorporated into the closure. Achieving these goals can be facilitated in many cases by having a surgical assistant provide appropriate tissue retraction. It may also be helpful to gently pull up on the tissue being sutured to help define and separate it from the underlying layers (e.g., pulling conjunctiva away from Tenon’s fascia, or orbicularis muscle away from underlying fat).

Video 8.5 Different variations in hand position can be used to suture a wound, offering a range of possibilities to optimize visualization and ergonomics. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v005&t=video

Video 8.6 Stabilizing the wound edge to facilitate passage of the needle. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v006&t=video

Video 8.7 Forehand versus backhand needle pass. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v007&t=video

Video 8.8 Needle holder locking mechanism. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v008&t=video

8.3 Passing the Needle and Thread through the Tissue

Once the needle holder is properly loaded, and the tissue to be sutured is stabilized with forceps, the needle may be passed into the tissue. This can be done with either hand, using a forehand or backhand technique, depending on the particular requirements and ergonomics of the situation ( Video 8.7). When using a locking needle holder, the locking mechanism should be released by compressing and maintaining compression of the flexible handles prior to entering the tissue ( Video 8.8). This will allow an easy release of the needle at the completion of the pass, and avoid any difficulties with the release mechanism while the needle tip may still be in the tissue. It may also be advantageous, if the situation permits, to pass the needle through both sides of the wound in a single pass. This requires a needle of sufficient length and proper curvature, but doing so will result in fewer overall manipulations of the needle, improving efficiency and reducing the risk of damage to the sharp tip.

Although it seems counterintuitive, bringing the tip of a curved needle back to the surface of the tissue generally does not require major torque to be applied to the needle body. The cutting edges at the tip combined with the curved body will do the work. Only a mild rotational force must be exerted to redirect the tip as the needle is advanced. This will allow the needle to follow its natural curve in exiting the tissue. Applying strong torque to the body of a delicate ophthalmic needle in an effort to force or drive the tip outward will not be effective, and should be avoided. Doing so will only result in the needle becoming bent and damaged ( Fig. 8.3, Video 8.9). This is particularly true for the longer scleral passes often utilized in strabismus surgery employing thin spatulated needles. Finally, it is helpful to hold the distal wound edge securely in place until the needle is re-grasped, particularly if there is any tendency for tissue retraction. This will minimize the potential for the needle to retract back into or out of the tissue when it is released from the needle holder ( Video 8.10). When the front of the needle is re-grasped to pull it out of the tissue, avoid grasping the tip, as this will cause it to become significantly dulled or bent, making subsequent passes more difficult and more traumatic ( Fig. 8.4, Video 8.11).

8.3.2 Technique: Tissue-Specific Considerations

The proper angle of needle entry into the tissue will depend on the situation. This may seem like a subtle technical consideration, but it is extremely important for two reasons. It is a major determinant of the quality and uniformity of the stitch, and it can prevent unintended ocular perforation or entry into deeper tissue layers. For skin, muscle, tendon, tarsus, fascia, and conjunctiva, a steep, roughly perpendicular entry and exit are preferred ( Video 8.12). Although the same is true for cornea, much greater precision is required to avoid full-thickness penetration. For corneal sutures, this is best accomplished by using a very sharp, tightly curved, spatulated needle.

For sclera, on the other hand, a shallow trajectory for needle entry is required ( Video 8.13). It is also ideal to “see” the needle, or the outward bulge of the superficial scleral fibers as the needle splits the scleral lamellae, for the entire length of the pass. A steep initial trajectory, or an attempt to pass the needle in a very deep scleral plane, greatly increases the risk of intraocular penetration. This risk is increased when the intraocular pressure is low, since the scleral surface will have a tendency to indent and buckle, making a shallow, uniform, lamellar pass more difficult. In certain cases (e.g., scleral port incisions, limbal incisions in pediatric cataract surgery), it may actually be advantageous to preplace sutures in corneal or scleral incisions early in the case, when the hypotony is less severe or absent, and conditions more controlled. In cases in which the eye is closed, but soft (e.g., as may occur during the course of scleral buckling or a difficult strabismus surgery), the surgeon or assistant may be able to apply some external pressure to the globe away from the suture site to temporarily increase the firmness of the eye. Doing so may facilitate the surgeon’s ability to pass the needle safely and uniformly through the sclera.

Fig. 8.3 (a) An intact spatula needle and (b) one bent at the posterior third of the body due to inappropriate torque applied to the body during the pass.

Video 8.9 Needle pass without and with torque. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v009&t=video

Video 8.10 Stabilization of exit side to facilitate completion of pass and prevent needle retraction. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v010&t=video

Fig. 8.4 Tip of an intact S-29 needle (a) and one in which the tip has been bent (b) from improper handling. The small burr noted at the tip of the intact needle was present in the packaging.

When intraocular needle penetration does occur, it can sometimes be felt as a subtle “give,” or “pop,” as the needle tip passes through the inner surface of the sclera to enter the low-resistance suprachoroidal space. Other signs of intraocular penetration include a rapid loss of intraocular pressure, blood or aqueous egress at the suture’s entry or exit points, or the presence of darkly pigmented uveal tissue at the exit site. Full-thickness sutures in the cornea or sclera carry an increased risk of endophthalmitis, wound leak, and hypotony. In the case of sclera, full thickness passes also increase the risk for retinal perforation, retinal detachment, and intraocular hemorrhage.

Video 8.11 Pulling the needle out of the tissue without damaging the tip. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v011&t=video

Video 8.12 Steep versus shallow needle entry. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v012&t=video

Video 8.13 Shallow needle pass appropriate for sclera. https://www.thieme.de/de/q.htm?p=opn/tp/300500101/9781626237308_c008_v013&t=video

8.4 Additional Considerations

In general, it is desirable to make symmetric needle passes on each side of a wound, with regard to both depth and distance from the wound edge ( Fig. 8.5). This will ensure an even distribution of the tension across the wound, as well as maintaining correct apposition of tissue layers.

8.4.2 Distance

The appropriate distance of the needle entry and exit points from the wound edges will depend on a number of factors, including the tensile strength of the tissue, the tension on the wound, and the blood supply on each side. Lower tissue tensile strength, increased tension, and poor blood supply require longer bites. In the sclera and conjunctiva, relatively long bites are typically not necessary and may actually lead to buckling or inward folding of the tissue. In the cornea, the length of the sutures should be sufficiently long to permit them to be easily rotated to bury the knots in the suture tract.

8.4.3 Depth

In the cornea, the suture depth should approach 90% of tissue thickness to avoid internal wound gape and ensure maximal tissue apposition and strength. In sclera, where tissue tensile strength is high and minor internal wound gape is not a major issue, the suture depth should not exceed 75%. The actual depth, however, should be tailored to the specific situation. For example, greater suture depth is needed to close full-thickness scleral defects or secure scleral buckles, while shallower depths are preferred for the fixation of glaucoma drainage devices or securing extraocular muscles. Keep in mind that the thickness of normal human sclera is approximately 750 μm at the limbus, and only 350 to 400 μm at the rectus muscle insertions and equator. It may be even thinner in highly myopic eyes or eyes with previous inflammation or trauma. In conjunctiva, the passes are always full thickness, but care should be taken to avoid incarcerating Tenon’s fascia in the surface closure. For skin, the suture should extend down to the dermis to utilize the tensile strength it affords. A separate deeper layer of suture (e.g., in the muscle or deep fascia) can be employed in the periocular soft tissues if necessary to improve wound strength and reduce tension at the surface.

Fig. 8.5 Proper symmetry of suture entry and exit on both sides of wound.

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