2-3. INTRODUCTION
The OR specialist hears the surgeon's request for "suture" in practically every surgical procedure. Because he handles sutures for use by the surgeon, the specialist must be able to identify them by their correct name and size. Following are appropriate terminology and descriptions concerning sutures.
a. Suture. A suture is a piece of thread-like material used to stitch or approximate tissues, and hold the wound together until healing takes place.
b. Absorbable Suture. An absorbable suture is made from material that can be absorbed (digested) by body cells and fluids. Rate of absorption depends on various factors, including type of body tissue, nutritional status of the patient, and the presence of infection. Absorbable suture is available prepackaged and presterilized in various sizes graded by diameter and length. Sizes range from number 12-0, which is the finest, to number 5, which is the heaviest. The length ranges from 12 to 60 inches.
(1) Plain gut. Plain indicates a surgical gut material that has not been treated to lengthen its absorption time in the tissue. This suture is absorbed more rapidly than treated suture. Plain gut suture is chosen most often by the surgeon for use in tissues that heal rapidly. As an example, plain suture is used extensively in tying off subcutaneous bleeding points. Its source is the sheep's intestine or beef serosa.
(2) Chromic gut. The second suture material in the absorbable category is the chromic surgical gut. Chromic surgical gut has been treated with chromic oxide so that it will delay its rate of digestion or absorption. Chromic sutures are treated to different (mild and medium) degrees to retard absorption. Its source is the same as that of plain surgical gut. It is used in tissues that have a relatively slow rate of healing and need support for a longer period. (An example is fascia.)
c. Nonabsorbable Suture. This suture material is not absorbed during the healing process. Nonabsorbable suture becomes encapsulated (enclosed in a capsule) with tissue and remains in the body until it is removed or cast off. Silk, nylon, cotton, and corrosion-resisting steel wire are examples of nonabsorbable sutures. Sutures used for skin closure are usually removed before healing is complete.
(1) Silk. Silk suture material is obtained from the continuous thread spun by the silkworm. Silk is used principally in clean surgery such as tendon repair, hernia repair, and surgery involving the nerves and blood vessels. It ranges in size from very fine number 9-0 used in eye surgery, to heavy number five used as a retention suture.
(a) Like the absorbable sutures, silk is available prepackaged, precut in many strands, and presterilized. Prepackaged, precut, and presterilized sutures usually are 18 inches long for interrupted sutures and 24 to 30 inches for continuous sutures.
(b) Silk is available braided and twisted. Braided is most commonly used because of the added tensile strength provided by the braiding process. Silk is treated so that it is noncapillary; that is, it is treated so that moisture and bacteria cannot enter the spaces or gaps within the woven silk fibers.
(2) Nylon. Nylon is a synthetic material most commonly used in plastic surgery. Nylon is stronger than silk. Nylon sutures are available in monofilament (single strand) in sizes ranging from number 5-0 to 0, and the multifilament (braided) in sizes from number 6-0 to 5.
(3) Polypropylene. Polypropylene is a clear or pigmented polymer. This monofilament suture material is used for cardio-vascular, general, and plastic surgery. Polypropylene is extremely inert in tissue, has high tensile strength, causes minimal tissue reaction, and holds knots well. Surgeons have indicated that polypropylene sutures can be tied into more secure knots than most other synthetic suture materials. Sizes available are number 7-0 to 2, swaged to needles.
(4) Linen. Surgical linen is made of twisted linen thread that has sufficient tensile strength to be used as suture material. It may be impregnated with a nonpermeable material that makes it smooth and noncapillary. Linen is used almost exclusively in gastrointestinal surgery, sometimes as a purse-string suture around the stump of the appendix or as a skin suture.
(5) Cotton. Surgical cotton is a nonabsorbable suture that is made from long staple cotton treated to make it smooth. Cotton is used in the same areas in which silk is used. It is available in size number 5-0 to 2. It is also available prepackaged, precut, and presterilized. Cotton suture is twisted rather than braided. It is free from lint, fuzz, and knots, and has a smooth shiny surface. Ordinary cotton has neither the smoothness nor the tensile strength required for suturing.
(6) Steel. Corrosion-resisting steel wire is used for metallic sutures. It is available precut, prepackaged, and on spools. It is also available in single strands (monostrands) and multistrands several strands of small diameter twisted together). Corrosion-resisting (stainless) steel is available in sizes ranging from number 6-0, fine to 2, heavy. Steel size may also be expressed in gauge: 18 to 40.
d. Dead Space. Space caused by a separation of wound edges that have not been closed by sutures is dead space. A dead space may interfere with healing.
e. Ligature (tie). A ligature is a thread-like material used to tie off a blood vessel or other tube-like tissue. A ligature or tie is usually of the same material as that used for sutures, but in some cases, it may be a silver clip.
f. Stick-tie (Suture-ligature). This is a ligature threaded on a needle and used to suture a vessel wall in addition to being tied around the vessel.
g. Tensile Strength. This refers to the amount of weight or pull that may be exerted on the suture before it will break.
h. Primary Suture Line. A line of sutures that holds the wound edges in approximation is known as the primary suture line.
i. Secondary Suture Line. A line of sutures that relieves the primary suture line of unusual stress, decreases or obliterates dead space, and prevents the collection of serum in the wound known as the secondary suture line or retention stitch.
2-4. METHODS OF WOUND HEALING
To understand why a wound is sutured, the specialist must know how healing occurs. Injured tissue is replaced by fibrous connective tissue (scar tissue), and the healing process may be classified as follows:
a. Primary Intention. The type of healing that occurs when an aseptic, incised wound is closed with sutures is primary intention. The healing takes place at all levels of the incised area; there is no swelling, no infection, and no separation of wound edges. A minimum of scar tissue ("hairline" scar) follows this type of healing.
b. Secondary Intention. Secondary intention is the healing that occurs from the depth of the wound outward or upward, each layer healing separately by granulation of tissue. This kind of healing is usually attended by the formation of a large amount of scar tissue, or it may be characterized by a weak union of tissue that breaks down later. This type of healing may occur as the result of one of a number of factors, including the following: poor physical condition of the patient, excessive trauma to tissue, loss of tissue, and infection. In the presence of infection, the surgeon leaves the wound open purposely in order to be able to keep it cleansed and dressed while it is healing. Whatever the reason is for healing by secondary intention, the union is delayed.
c. Third Intention. When gross infection exists, when a large amount of tissue is removed, and for some battle wounds, surgeons may leave wounds open for about four to seven days to observe them for development of infection. Nevertheless, when it can be done, primary intention is preferred over third intention because, in the former, minimum scar tissue results, healing occurs more rapidly, less chance of contamination occurs, and a stronger union of tissue results.
2-5. TYPES AND LAYERS OF TISSUE REQUIRING CLOSURE
In order to accomplish wound closure, the sutures are placed to hold the edges of the tissue layers in approximation until the wound is fairly well healed. The tissue layers that require closing vary with the body area involved. For example, the tissue layers closed in abdominal surgery differ from the layers closed in orthopedic surgery.
a. Abdominal Surgery. The layers of tissue to be closed, beginning with the deepest layer and going toward the periphery, are: the peritoneum, the deep fascia, the muscle, the superficial fascia, the subcutaneous tissue, and the skin. (There are two layers of fascia since muscle tissue is covered or enclosed in fascia.) Many times the muscle and one layer of fascia are sutured together because these structures are immediately adjacent to each other.
b. Orthopedic Surgery. The layers of tissue to be approximated following bone surgery (for example, the tissue over the humerus) are: the periosteum or bone covering, the deep fascia, the muscle, the superficial fascia, the subcutaneous tissue, and the skin.
2-6. TECHNIQUES OF APPROXIMATING TISSUE
Techniques of approximating tissue and the nomenclature for the various type of stitches are discussed in the following paragraphs.
NOTE: Figure 2-2 shows the principle suturing techniques.
a. Continuous Stitch (See figure 2-2). This is a running stitch with the suture tied only at the ends of the incision.
b. Interrupted Stitch (See figure 2-2). With this technique, each stitch is taken and tied separately. Each stitch may be tied when it is put in place, or the stitches may be tied after all have been placed.
c. Purse-String Stitch (See figure 2-2). This is a continuous stitch placed so that it can be closed in a drawstring manner. The technique is to place a running stitch around the lumen of a structure. For example, it is used to close the intestinal wall when the appendix is removed and the stump inverted. After placement, the suture is tightened by grasping both ends and drawing the lumen closed.
Figure 2-2. Principal suturing techniques.
d. Tension (Stay or Retention) Stitch (See figure 2-2). This is an interrupted stitch used to reinforce a primary suture line. The suture is placed through many layers of tissue on each side of the incision (down to and sometimes including the peritoneum (serous membrane lining the abdominal cavity). Stay sutures are of a heavy, nonabsorbable material, such as wire or heavy silk (sizes 2 or 3). When a heavy suture is used, the skin beneath the knot must be protected to prevent its being cut by the suture. Therefore, when silk is used, surgical buttons may be used on both ends of the suture where it is tied. When wire is used, rubber shods (small pieces of rubber tubing) are used to protect the skin where the wire is tied. The rubber shods extend over the incision line.
e. Subcuticular Stitch (See figure 2-2). With this technique, short continuous stitches are taken laterally inside the incision. The stitches are placed in the dermis. The suture is brought through the surface of the skin at each end of the incision only and is secured by either clamping a perforated lead shot on each end of it or tying it at each end. This technique of skin closure leaves a minimal scar; therefore, it is used frequently for closing the skin of the face and neck and for surgery done on children. The suture may be removed by cutting off one end and pulling the entire suture out at the other end. However, if the suture is absorbable, the surgeon may prefer to leave it in permanently.
2-7. SURGEON'S PREFERENCE FOR SUTURES AND STITCHES
a. Types of Sutures to be Used. The surgeon prescribes the types of sutures, needles, and stitches required for wound closure. This information is entered on a surgeon's card (see figure 2-3) for each surgeon and each operation. The cards are kept on file in the surgical suite. The specialist obtains this information by checking the card file. Information is entered on the card in an abbreviated form, and the specialist is expected to be able to understand the information in order that he may correctly prepare the necessary sutures for the procedure.
b. Example of Entries on Cards. Assume that Dr. Able is to perform an appendectomy, and the card shown in figure 2-3 is to be used.
| SAMPLE APPENDECTOMY CARD | Dr. ABLE
|
| |
Figure 2-3. Suture (surgeon's preference) card.
(1) Plain size 000 ties (ligatures, para 2-3e). This indicates that "free" pieces of plain size 000 catgut are desired to tie off cut blood vessels in the subcutaneous tissues. The suture may be wound around an unbroken suture tube or cut in 15-inch (single) lengths, depending upon the surgeon's desire.
(2) Size 3-0 black silk--French-eye needle--purse-string. This means that size 3-0 silk, about 18 inches long, will be required for the purse-string, and that the silk is to be threaded into a French-eye needle. The purse-string stitch will close the lumen in the cecum after the appendix has been removed.
(3) Chromic 0-size 3 Murphy needle--continuous--peritoneum. This information means that a single suture of chromic size 0 with a Murphy needle size 3 is required to close the peritoneum, and that a continuous suture is used. Since a continuous suture is tied only at the ends of the incision, the length of suture needed for this closure depends upon the length of the incision. For many operations, half of a strand of suture is sufficient.
(4) Chromic 0-size 3 Murphy needle--interrupted--muscle and fascia. "Chromic 0" and "size 3 Murphy" have the same meaning as in (3) above. "Interrupted" means that this surgeon will place and tie each stitch separately when closing the muscle. The length required for interrupted suture is usually 15 inches long. However, the suture may need to be shorter or longer, depending upon the depth of the tissue layer.
(5) Plain 000--size 2 Murphy needle--interrupted--subcutaneous. This indicates that for closure of the subcutaneous tissue, the surgeon requires plain size 000 surgical gut (in quarter lengths) on a size 2 Murphy needle, and that he will take each stitch separately. The needle is of a larger size (see figure 2-4) than that mentioned in (4) above in order that it will go through the subcutaneous layer of tissue.
NOTE: The higher the number of a needle, the smaller the needle.
(6) Size 3-0--black silk--Keith needle--interrupted--skin. According to this notation, the surgeon will close the skin using a Keith (straight) needle that is used without a needle holder. Each stitch is taken separately, the size 3-0 silk should be about 15 inches long.
c. Specialist's Duties in Maintenance of Card File. The cards may be taken into the OR for use, but the specialist who uses them has the responsibility of returning them to their proper place for future reference. The specialist has further duties in the maintenance of this file, as follows:
(1) Change in the surgeon's routine. The surgeon is at liberty to change his suture routine at any time. Whenever he does so, the scrub must report these changes to the OR supervisor in order that the changes may be entered on the card.
Figure 2-4. Sizes of needles.
(2) Preparation of new cards. When a surgeon, new to a hospital, operates for the first time, the specialist assigned for the case has the responsibility of making a list of the sutures, the types of stitches, and the needles desired. The list is given to the OR supervisor in order that the information may be entered on a card.
2-8. PREPARATION BY SPECIALISTS
a. Circulator. The circulator supplies the necessary kind and amount of sutures required for the operative procedure, according to the information listed on the card for the surgeon and the operation.
b. Scrub. The scrub prepares all needed sutures for the case and hands them to the surgeon at the appropriate time. The scrub's first step in the preparation of sutures is to check the appropriate card for the operative procedure before scrubbing.
2-9. PROCEDURES FOR PREPARATION OF SUTURES
Sutures used in the OR are in a plastic packet or foil packet. First identify them; then open them. When preparing sutures, always prepare them in order of use.
a. Opening Individual Sealed Containers. To open a foil packet, cut near the sealed edge or tear along the dotted line of the packet and withdraw the suture (see figure 2-5 A).
b. Unwinding the Suture. To unwind the strand of suture, break a prong off the reel. Place one or two fingers within the center of the loop while carefully unwinding and straightening out the suture (see figure 2-5 B). Straighten the suture as follows: hold both ends of the suture in one hand, the center of the loop in the other, and gently pull the hands apart (see figure 2-5 C). Never stretch, jerk, nor test the strength of suture while handling it, as this would weaken the strand. Do not run gloved hands over the suture to straighten kinks, and do not handle the suture any more than is necessary. Always work over the sterile field as a precaution against contamination. Avoid letting the suture ends drop over the edge of the table. The procedure for opening a package with a swaged-on or a traumatic (affixed) needle is as that just described, except for two points:
(1) After taking the suture from the package, grasp the end of the suture with one hand; grasp the other end of the suture, just below the needle, with the other hand.
(2) With the hands in the position described, gently straighten the suture. Do not exert any pull on the needle.
Figure 2-5. Preparation of sutures.
c. Cutting the Suture into Lengths. The next step is to cut the suture into lengths appropriate for its use and place it under the cover towel on the Mayo tray in the order of use. Standard absorbable suture comes in several lengths: 12, 18, 27, 36, and 54 inches. If necessary, this suture is cut into halves, thirds, and fourths, and so forth, depending upon the area in which it is to be used and the original length. Prepackaged silk suture comes in lengths of 18, 24, 30, 40, and 60 inches and on spools.
d. Threading a French-Eye Needle (See figure 2-6). Thread a French-eye needle by bringing the suture down through the slit into the eye. Be careful when threading a French-eye needle because the eye is easily broken. There is a spring opening through the end of the needle into the eye. French eye needles are easily broken. Check to see that the needle's eye is intact before threading.
Figure 2-6. Threading a French eye needle.
e. Threading Other Curved Suture Needles (See figure 2-7). Thread the needle from inside its curve with the short end of the suture on the outside. This method helps prevent unthreading. Proceed as follows: grasp the needle on its flat surface about one inch away from its eye with a needle holder. Pull about 5 inches of the suture through the eye of the needle.
Figure 2-7. Threading of a curved suture needle.
2-10. PROCEDURES FOR HANDLING OF SUTURES
After handing a tie or suture to the surgeon, hand suture scissors to his assistant.
a. "Free" Ties. Hand the length of suture on the reel to the surgeon when he is ready for it. If the surgeon prefers to handle each tie separately, hand quarter-length strands (15 inches) to the surgeon one at a time by holding one end of the strand in each of your hands and placing the strand with gentle pressure across the palm of the surgeon's hand.
b. Stick-Ties. Thread a quarter-length ligature on a curved, cutting-edge needle (a longer suture may be needed if the surgeon is working very deep). When the surgeon requests a stick-tie, clamp the needle firmly with the needle holder about 1/3 inch from the eye to prevent unnecessary stress on the needle, possibly causing it to break when passed through the tissue. Pass the needle holder to the surgeon by placing the handle firmly into his palm, the needle pointing as for use and the suture material falling over the back of the hand, out of his way, and so that he may place the suture without shifting the needle holder.
c. Purse-String Suture. Pass this suture to the surgeon on a needle holder as described in paragraph "b" above. The purse-string suture is a fine silk suture, always prepared dry.
d. Peritoneal Suture. Pass the suture on a needle holder as previously described (paragraph "b" above) and give the end of the suture to the assistant, who will hold it in order that it will not hang over the edge of the sterile field and become contaminated. Pass a dressing forceps to the surgeon in his other hand, which he uses to hold the peritoneum together while suturing.
e. Interrupted Sutures for Muscle and Fascia. Pass the suture that is used for the muscle and fascia to the surgeon on a Murphy needle in the usual manner (paragraph "b" above). To save time and material, cut the remaining peritoneal suture and use it for these interrupted sutures (when the same suture material is used for all of these tissues). In order to keep the surgeon supplied with interrupted sutures, keep one suture ahead of the surgeon because when the surgeon finishes placing a suture, the next one should be ready. Since speed is essential in this procedure, you should practice until able to perform the procedure rapidly and accurately.
f. Interrupted Sutures for Subcutaneous Tissue. Pass these sutures to the surgeon on Murphy needles as described above. Usually, the suture for subcutaneous tissue is the same as that used for ties. Whenever this is the case, suture left over from the ties is utilized here.
g. Interrupted Sutures for Skin Closure. When passing the silk suture on a Keith (straight cutting) needle to the surgeon, also hand him an Adson forceps with which to hold the skin edges. Prepare the skin sutures so that as the surgeon finishes placing one suture, another is ready for him, as with any other type of interrupted suture. Be careful in passing this suture in order that the point of the Keith needle does not pierce or tear the surgeon's glove. Hand the needle with its eye toward the surgeon. A good technique is to place three Keith needles on a folded towel with the points of the needle placed through a thread in the towel. When the surgeon places a suture, he returns the needle to the towel.
h. Metal Clips for Skin Closure. Although silk is usually used for closing the skin, the surgeon may prefer to use skin clips. The clips used for this purpose are Michel clips (small metal clips with prongs at either end). Prepare the clips for use by stringing several clips on a piece of wire that serves as a holder. Cut off the ends of this wire holder to facilitate picking up the clips with the applier. The surgeon applies the clips by means of an instrument, which holds them and squeezes them so that the prongs go into the skin and the clip is bent into a "U" shape. The surgeon uses tissue forceps to pull the skin in approximation while applying the clips. Stabilize the clip holder on an unbroken tube of suture in order that the surgeon may grasp the clips more easily.
i. Tension Sutures.
(1) Wire. When a wire tension suture is required, thread the wire through a heavy, large, curved, cutting-edge needle at least 3 1/2 inches long. Avoid kinking the wire while threading it, and thread rubber shods (see para 2-6d) over the wire to prevent it from cutting into the skin. Clamp a hemostat on the long end of the wire to keep the rubber shods from slipping off prior to and during use. Carefully bend, but never twist, the short end of the suture, as this would place too much bulk at the needle's eye. No more than 3 or 4 of these sutures are needed for an incision 8 or 9 inches long.
(a) The surgeon usually places tension sutures before he sutures any of the layers of tissue. Pass this suture to the surgeon along with the tissue forceps, and hand the hemostat on the long end of the wire to the assistant for handling.
(b) Tension sutures are not tied until the skin closure has been completed. When the wire is ready to be tied, pass scissors used only for cutting wire to the assistant. Do not pass the suture scissors for this purpose, as the wire would dull them. The assistant cuts the sutures after they have been tied by the surgeon.
(2) Silk. When silk is used for a stay or tension suture, a heavy size such as number two is used. It is prepared at least 28 inches long. Using the fingers, thread this silk through two holes of a button from the bottom upward, across the top of the button and downward again. The button will then be hanging in the middle of the suture so that when the ends are brought together the smooth (concave) surface of the bottom will be toward the ends of the suture. Grasp both ends of the silk between the fingers, and thread them both simultaneously through the needle eye, as though a single strand. Allow a tail about 4 inches long to hang free.
(a) The surgeon inserts this suture approximately 1¼ inches from the edge of the incision and, when he pulls it through, places the button against the patient's skin.
(b) When the surgeon is ready to tie this suture, hand the second button to his assistant, who threads it with the free ends of suture on the opposite side of the incision. The knot is tied over the second button. This suture does not cross the incisional line on the skin surface.
j. Summary. The skill of assisting with the aseptic procedure of suturing is developed through practice and experience, but it is imperative that amounts and kinds of suture be determined before starting an operative procedure, to avoid waste of time and materials. Suture is expensive and must be handled accordingly. Suture cards must be checked frequently and maintained in detail, if they are to be effective are a useful guide in the preparation of sutures for a surgical procedure. Proficiency in the handling of suture material can and must be developed by the OR specialist.