John C. Elkas and Addie Alkhas
It is imperative that surgeons understand the choice and limitations of their instruments and sutures with regard to a planned surgery. This knowledge will often make the difference between struggling or proceeding with purpose. Keeping current on the rapid and ongoing development of instrument technology can be difficult for the busy clinician. Yet taking advantage of these innovations can contribute significantly toward efficiently completing a challenging case. Surgical proficiency requires a well-planned approach with an appreciation and knowledge of the instruments and sutures to be used.
Every surgeon has a preference for selecting particular instruments as a result of training and experience. Later, these choices are often modified by acquired habits and limits imposed by cost. Surgical instruments are an extension of a surgeon’s hands and are designed to facilitate the operative procedure. The list of instruments provided in this chapter is neither comprehensive nor complete. What follows is a functional description of the basic tools for the gynecologic surgeon.
The Bard-Parker handle is usually fitted with a disposable blade that is attached using a needle holder. Commonly, the #10 or #20 blade is used for the skin incision and can then be used to extend the incision through the fascia. The #15 blade has a small area useful for confined spaces or small skin incisions. The #11 blade has a straight edge useful for its pointed design in placing drains or opening abscesses. There are also long and curved handles to facilitate dissection in the deep pelvis.
Scissors, with their long handles and strong blades, serve multiple functions in the operative field from cutting sutures, excising scar tissue, and transecting pedicles to fine dissection of adhesions involving intra-abdominal viscera. Surgical scissors usually come in various sizes and lengths, with straight and curved blades having chamfered or rounded ends. Examples of these are the Mayo and Metzenbaum scissors. The Jorgenson scissors are heavy scissors with sharply curved blades that facilitate the amputation of the cervix off the vaginal cuff.
Thumb forceps, as the term suggests, act as an extension of the surgeons thumb and index finger for grasping tissue, steadying needles, or exploration. Spring tension keeps the tips apart until pressure is applied to close them. Forceps have a variety of widths and lengths, making them versatile and universally applicable in the operative field. The blade’s design and surface configuration will determine its intended use. Adson forceps are used for manipulating the skin, whereas Bonney or Martin forceps have teeth for handling fascia. DeBakey or smooth forceps with a cross-serrated grasping surface make them ideal for handling peritoneum or vascular pedicles. Singley forceps with their fenestration are ideal in atraumatic handling of tissue bundles during lymphatic dissection. Hemostatic forceps (clamps) are light instruments with spring handles, ratcheting closing mechanisms, and fine tips, making them ideal for isolating bleeding points, grasping small vascular pedicles, and careful dissection in the pelvis. They come in an assortment of sizes and lengths, making them very useful instruments. The Halsted mosquito forceps, Kelly clamps, Tonsils, Rochester-Ochsner, and Mixter forceps are a few other often-used forceps.
Because of the rich, extensive, and collateralized blood supply to the uterus, these clamps are designed to secure and maintain large vascular pedicles within their jaws while minimizing the trauma to the surrounding tissue. A ratchet locking device in the handle, serrations in the jaw, and teeth at the tips allow for a pedicle to be transected and ligated safely. Tissue slippage can result in extensive bleeding that is difficult to control, risking injury to the ureters as well as larger vessels. These clamps are generally at least 20 cm long and have curved or straight jaws or angled handles. The longitudinal serrations tend to be preferred because they prevent slippage of tissue from the clamp. Examples include the Heaney-Ballentine clamps, which have teeth at their tips to ensure secure bite at the cost of crushing the tissue; the Masterson clamp, which was designed to generate less crushing force by lacking the toothed tip; and the Zeppelin clamps, which may best satisfy the requirements for the use in complex pelvic procedures—greater holding force and minimal tissue trauma and slippage. In addition to the full range of abdominal Zeppelin clamp configurations, different sizes and curves are also available for vaginal surgery (Figure 23-1).
FIGURE 23-1. Zeppelin clamps.
Clip applicators are effective in obtaining hemostasis of small vessels deep in the pelvis or when performing a lymph node dissection to prevent lymphatic drainage. The applicator comes as a reusable single clip applicator with straight or angled head or as a disposable instrument with multiple loads. The applicators usually come in 3 sizes: small, medium, and large. After clip application, caution should be used with the use of the electrosurgical unit or suction device because of potentially unrecognized injury by thermal spread or dislodged clips causing rents in serosal surfaces or vascular structures.
Surgery for ovarian cancer is normally performed through a midline laparotomy because evaluation of both pelvic and abdominal structures is required. A self-retaining retractor is essential to optimizing exposure, maximizing patient safety, and reducing surgeon fatigue. Of the available models of self-retaining retractors, those with a fixed arm attaching the retractor ring to the operating table are best suited for ovarian cancer surgery. The Bookwalter retractor is the standard self-retaining fixed-ring retractor and is versatile enough to be adapted to a variety of operative requirements. The retractor clips that attach the blades to the ring allow for 2-dimensional adjustments of the blade position in relation to the surgical field. The oval ring of the Bookwalter is most commonly used for ovarian cancer surgery, but circular and hinged rings are also available depending on the exposure needed. For example, the hinged ring can be used to surgical advantage when operating in the upper abdomen (eg, diaphragm, liver, spleen) by increasing the angulation of the retractor blade to provide more pronounced ventral displacement of the costal margin, improving exposure.
The Omni retractor has 2 adjustable “boomerang-shaped” arms that are attached to a fixed post. Each arm can be moved in 3 dimensions, and finer modifications in exposure can be achieved with the adjustable retractor blades as opposed to the fixed ring. The Omni retractor is especially helpful when operating on obese patients, because the extent of lateral retraction is not limited by the width of a retractor ring (eg, Bookwalter). Nonfixed, self-retaining retractors, such as the Balfour and O’Connor-O’Sullivan retractors, can also be used, but they are more limited in their field of exposure and are less steady than the fixed models because they are stabilized only by creating pressure on the opposing sides of the abdominal wall incision. In addition to limited exposure, self-retaining retractors have been associated with iatrogenic nerve injury due to compression of the femoral nerve in as many as 7.5% of cases.1Although retractors such as the Omni and Bookwalter may be associated with nerve injury as well, the elevation of the abdominal wall provided by these retractors may help to minimize this risk. With any self-retaining or fixed retractor, the surgeon must exercise particular attention when placing the blades along the lateral abdominal wall so as not to compress the psoas muscle and traumatize the underlying femoral nerve. The risk of femoral nerve injury may also be increased by extended Pfannenstiel incisions, thin habitus (body mass index < 20 kg/m2), narrow pelvis, and prolonged surgical time greater than 4 hours (Figure 23-2).
FIGURE 23-2. Bookwalter self-retaining retractor.
The needle holder serves to guide and place a needle through tissue and then retrieve it. They are designed with various lengths and straight or curved jaws to facilitate their placement. A fine locking mechanism and serrated jaws assist with control of the needle to prevent unnecessary bleeding and tissue damage. Considerations for correct needle choice and caution with grasping the needle can prevent the needle from bending or breaking. Curved tips are preferred in vaginal surgery to aide with visualization and placement of the needle. However, the straight tip allows for better control of the needle with more precise placement. The Mayo-Hegar and DeBakey’s are 2 commonly used needle holders.
The Electrosurgical Unit and Vessel Sealant Devices
The electrosurgical unit (ESU) (Force 2; ValleyLab, Boulder, CO) consists of a generator and electrodes and is probably the most commonly used instrument in ovarian cancer surgery. The ESU uses radiofrequency electrosurgery to oscillate intracellular ions, which converts electromagnetic energy to mechanical energy and then to thermal energy. The ESU can be configured with either monopolar or bipolar electrodes. The monopolar electrode is versatile and can be used for cutting, desiccation, and fulguration. With cutting current, a continuous high-frequency flow leads to a rapid buildup of heat and vaporization of intracellular water, resulting in local tissue disintegration without a significant coagulative effect but with minimal lateral heat transfer. In contrast, coagulation mode uses an interrupted current of lower energy, which leads to a slower heating of intracellular water, increasing the resistance to flow and producing a more pronounced coagulative effect on small blood vessels. Often a combination (or blended) current produces the most satisfactory tissue effect. Generally the lowest effective generator settings should be used to avoid excessive thermal damage to surrounding tissues. Customary settings for blended currents range from 30 to 50 W. With monopolar electrodes, a grounding or dispersive pad needs to be applied to non–hair bearing, well-perfused, and dry skin close to the surgical site. The bipolar electrode uses a dual paddle design that conducts current to produce a tissue-coagulating effect. Bipolar devices conduct current only between the 2 paddles of the instrument, limiting the risk of electrical injury, especially when used during laparoscopy.
Automated Stapling Devices
Advanced-stage ovarian cancer commonly involves the intestinal tract by contiguous extension or distant peritoneal metastasis. Consequently, the surgeon must be familiar with a variety of techniques of bowel resection and anastomosis. Traditionally, these procedures were performed using hand-sewn suture techniques. The introduction of automated surgical stapling devices permits the same procedures to be performed with comparable efficacy, greater simplicity, and increased speed. There are multiple brands of commercially available automated stapling devices; however, all use the same basic principle of compressing an inverted “U-shaped” staple into a “sideways B” in the closed position. The closed staple position secures the tissue contained within but does not constrict the vascular supply to the resulting staple line with the exception of the vascular load staplers.
There are 3 basic categories of automated stapling devices used for bowel surgery as well as other purposes. All contemporary stapling devices are single-use and disposable. The first category is the thoracoabdominal (TA) stapler, which lays down a double row of titanium staples staggered in an overlapping fashion. The TA stapler does not have a cutting component and therefore is used to close a segment of intestinal tract distal to the point of division or to close an enterotomy or colostomy created during one of various anastomotic techniques. The TA stapler is available in 3 different sizes (40, 60, and 90 mm) depending on the width of tissue to be secured. There are 2 standard staple sizes for the TA stapler, with the choice being dependent on the compression thickness of the stapled tissue. The 3.5-mm staple (open position) compresses to a thickness of approximately 1.5 mm in the closed position, whereas the 4.8-mm staple (open position) should be used for tissue that will compress to approximately 2.0 mm in the closed position. The Roticulator stapling device is a variation of the standard TA stapler that incorporates a rotating shaft and hinged cartridge head to allow greater flexibility of application. It is particularly useful when dividing a segment of colon or rectum deep in the pelvis. The Roticulator lays down a double row of 4.8-mm titanium staples 55 mm in length.
The second category of automated stapling devices is the gastrointestinal anastomosis (GIA) stapler, which lays down 2 double rows of staggered titanium staples and has a self-contained cutting blade that divides the tissue between the 2 staple lines. The GIA stapler is used to simultaneously secure and divide a segment of bowel or other tissue such as mesentery and is available in 2 lengths (60 and 80 mm) depending on the width of tissue. The basic staple sizes adapted for use in the GIA stapler are 3.8 mm, which compresses to 1.3 mm in the closed position, and 4.8 mm, which compresses to 2.0 mm in the closed position. Vascular load staple cartridges are also now in use with the GIA-type staplers that have a staple size of 2.5 mm, which compresses to 1.0 mm in the closed position. The staple line thus created is hemostatic for most small-caliber vascular pedicles.
The third category of automated stapling devices is the circular end-to-end anastomosis (CEEA) stapler. The CEEA stapler lays down a double row of circular staples and has a self-contained circular cutting blade that simultaneously excises the inverted internal tissue. The 4.8-mm staples compress to a tissue thickness of approximately 2 mm. The CEEA stapler is most commonly used to create end-to-end anastomosis of the colon but is also applicable to small bowel–small bowel and small bowel–colon anastomosis. Both straight and curved shafts are available variations of the CEEA stapler, although when performing a low colorectal anastomosis, navigation of the pelvic curvature is usually easier with the curved model. A low-profile detachable anvil is also available for the CEEA stapler, which is easier to place within the bowel lumen in some circumstances (eg, stapled end-to-side anastomosis). The standard CEEA stapler comes in 5 sizes that reflect the outer diameter of the circular stapler cartridge: 21, 25, 28, 31, and 33 mm. In general, the functional luminal diameter is approximately 10 mm smaller than the size of the stapler used to create the anastomosis.
Successful outcomes using automated surgical stapler to perform bowel anastomosis including colorectal anastomosis below the levator muscles have been reported in the gynecologic literature since the late 1970s. The rate of enteric anastomotic-related complications following trauma-related intestinal surgery has been confirmed to be similar regardless of whether an automated stapler or hand-sewn technique is used. In one of the largest case series documenting the use of end-to-end anastomosis stapling devices in the setting of radical gynecologic surgery, the 2 anastomotic breakdowns reported were noted in patients who had previously undergone radiation therapy.2 Some authors argue that the favorable outcomes associated with the use of automated stapling devices in patients with gynecologic malignancies are due, at least in part, to the improved blood flow to the anastomosis, a contention that has been confirmed in an animal model. It must be stressed that, in all instances, the method of anastomosis elected should reflect the technique with which the surgeon is the most comfortable. The specifications of the 3 types of automated stapling devices are depicted in Figures 23-3, 23-4, and 23-5.
FIGURE 23-3. Thoracoabdominal stapling device.
FIGURE 23-4. Gastrointestinal anastomosis stapling device.
FIGURE 23-5. Circular end-to-end anastomosis stapling device.
Recent innovations have been made to the GIA stapler to address issues related to bleeding at the staple line and enteric leakage. Many of these studies have been done in thoracic and bariatric surgery with endoscopic stapling devices but have applicability to open and hand-held devices as mentioned earlier. The new Ethicon Endo-Surgery Linear Cutter is the only linear cutter with 6-row, 3-dimensional surgical staple technology. It is a sterile, single-patient-use instrument that simultaneously staples and divides tissue. It may be used for transection, resection, and the creation of anastomoses. The 6-row stapling line is thought to provide superior hemostasis through added tissue compression. However, a recent German study of 362 patients comparing 4-row stapling in 148 patients to 6-row stapling in 214 patients noted a nonsignificant difference in anastomotic leak rate of 2.7% versus 3.7%, respectively. There was also a nonsignificant improvement in hemostasis.
A second innovation has been the use of reinforcement material in the staple line that is thought to redistribute tension evenly throughout, sealing off the staple holes and narrowing the spaces between the staples. Presently, several types of available reinforcement materials exist, such as Gore Seamguard, which contains a nonabsorbable and absorbable sleeve placed over each arm of the stapler prior to firing; Peri-Strips Dry with Veritas collagen matrix, which is an absorbable staple line made from bovine pericardium that is attached to the stapler with a gel; and the Duet TRS Reload with Tissue Reinforcement, which uses an absorbable polymer called Biosyn. The Duet TRS system has a preloaded Biosyn film attached to disposable staples, which makes use of this system rather straightforward. It also has the thinnest film thickness at 0.7 mm, potentially reducing misfiring on thick or edematous tissue. Several studies in animals and humans have demonstrated an increased burst pressure and decreased blood loss and leakage with reinforced staple lines. In a study by Jones et al1 published in 2008, bioabsorbable staple line reinforcement for circular staples in a gastrojejunal anastomosis using Gore Seamguard showed a significant reduction in the incidence of anastomotic strictures from 9.3% to 0.7%, which may improve the morbidity from low anterior resections during ovarian cancer tumor debulking. Large prospective trials comparing these staple systems to conventional systems are ongoing, so firm conclusions as to their cost effectiveness cannot yet be made.
Argon Beam Coagulator
Compared with the standard ESU, which conducts current through air, the argon beam coagulator (ABC) (Conmed Corp., Utica, NY) conducts radiofrequency current to the target tissue through a coaxial stream of inert argon gas that is regulated automatically. ABC power settings range from 70 to 150 W and are selected according to the type of tissue being treated (eg, 70-80 W for cauterizing small-caliber vessels, 110-120 W for treating the surface of the liver or spleen). The ABC does not come into direct contact with tissue; rather, as the current contacts the tissue with the stream of argon gas, individual arc tunnels are formed within the target tissue. It is the formation of these arc tunnels that is thought to account for a more uniform distribution of current within the tissue and therefore a more uniform coagulative effect with less thermal injury. The ABC can effectively cauterize vessels of up to 3 mm in diameter. The jet of argon gas serves to improve visualization of the operative field by displacing blood and debris. In addition to its utility in achieving hemostasis, the underlying coagulative necrosis generated by application of the ABC is an efficient means of destroying small-volume implants of meta-static ovarian cancer and may facilitate optimal cytoreduction of disease in sites inaccessible to conventional resection. Tumor destruction has been documented in areas such as bowel mesentery, the diaphragm, ureters, vagina, presacral space, and iliac vessels. When used for ovarian cancer tumor implant ablation, the depth of tissue destruction is dependent on both the power setting and tissue interaction time.
Recently, a group of surgical instruments referred to as “vessel sealers” have demonstrated clinical utility by simultaneously cauterizing a tissue pedicle and cutting it with a self-contained surgical knife (eg, Ligasure; ValleyLab) or with ultrasound energy (Harmonic ACE; Ethicon, Cincinnati, OH). The energy generated from these instruments reforms the collagen in the vessel walls and connective tissue, producing a permanent seal that can effectively cauterize vessels.
Specifically with the Harmonic ACE device, also available as a hand-held device, when tissue with high water content is exposed to low-frequency ultrasonic energy, intracellular vibrations cause the tissue shear stress threshold to be exceeded and tissue proteins to denature and cells to destruct. The Harmonic scalpels achieve tissue temperatures in the range of 60 to 80°C, resulting in coagulum formation without the desiccation and charring caused by temperatures of ≥80°C that are produced using electrosurgical methods. Because these effects are a product of mechanical vibration propagating in the direction of the applied force, collateral tissue damage is minimal. The device consists of a generator, reusable handpiece, and ultrasonic blade that vibrates at a specific frequency and at a programmable excursion. The generator has an acoustic transducer that converts the electrical energy into high-frequency vibrations. This energy is then transmitted through the aluminum handpiece to the tip of the blade. An advantage of the Harmonic ACE is that because of minimal collateral spread, it is ideal for use close to bowel and ureter, but caution must be used during prolonged use at high frequency because of the thermal damage that may be caused to adjacent tissue. Because of the mechanism for tissue coagulation, it produces minimal smoke and provides for better visualization of the operative field. It does require longer coagulation time for sealing of vessels as opposed to cauterizing instruments such as the LigaSure, but it may allow more versatility for dissection in lymphatic beds adjacent to major vasculature due to decreased thermal spread.
The LigaSure device uses bipolar electrothermal energy to seal vessels. It is an alternative to clips, staplers, suture ligatures, and ultrasonic devices. The collagen and elastin within the vessel wall are denatured through the application of a high-current and low-voltage (monopolar sources use a low-current, high-voltage energy source) electrical system, resulting in a wide seal. The pressure applied within the jaws reforms the denatured proteins within the apposed vessel into a translucent seal that is transected by a deploying knife. The electrosurgical circuit for the LigaSure device is a tissue response generator that senses the density of the tissue bundle held within the forceps housing the active and return electrodes. The generator’s circuitry automatically adjusts for an appropriate amount of energy to be delivered to the tissue, thereby effectively sealing it. The hemostatic plug is made from partially denatured and reformed collagen and elastin within the tissue bundle and blood vessels. Microscopically, the vessel wall fuses, obliterating the lumen. The recent development of the LigaSure Impact system using the TissueFect sensing technology with a ForceTriad energy platform has made it a formidable hand-held open surgical instrument. Its curved jaw and 180-degree rotating shaft allow for access into the deep pelvis. The electrode length is 36 mm, and its cutting length is 34 mm, allowing for substantial pedicles. When fired, it creates a seal width of 3.3 mm at its tip and 4.7 mm at the angle of the forceps. It is hand activated with a fusion cycle of 2 to 4 seconds and improved energy distribution, thus minimizing thermal spread. It uses an audible activation tone that changes from a continuous tone to a single short tone when the seal cycle is complete.
Vessel sealers can be adapted for both laparoscopic and open applications and are particularly useful for controlling vascular pedicles in areas that are difficult to reach. When using these instruments, 2 clinical issues must be considered. First, the maximal size of vessel capable of being effectively sealed and burst pressure must be known. The LigaSure device has been compared to the Harmonic ACE in the laboratory setting and found to be able to seal larger vessels (up to 7 mm in size vs. 5 mm) with a higher burst pressure. Second, peripheral energy spread must be known to minimize the risk of adjacent tissue injury. Although LigaSure has been shown to seal larger vessels at higher burst pressures, the Harmonic ACE has less than 1 mm of lateral thermal spread compared to the LigaSure, with as much as 6 mm lateral spread in some studies. Kyo et al,3 in a recent study citing their experience with the use of the LigaSure device during radical hysterectomies and exenterations, demonstrated decreased mean operative time and a significant decrease in blood loss and transfusion rates. In the general surgical literature, the LigaSure device has been instrumental in successfully completing laparoscopic splenectomies with a significant reduction in operative time and an average blood loss of less than 100 mL (Figure 23-6).
FIGURE 23-6. The LigaSure (Impact) vessel sealer.
Carbon Dioxide Laser
Laser is an acronym for “light amplification and stimulated emission of radiation.” The laser beam possesses a single wavelength with all the elements in phase and parallel to each other, which allows for precise and focused ablation of targeted tissue that has minimal lateral tissue damage. The power density is measured in watts per centimeter squared and is inversely proportional to the spot size. The system is composed of a power source, lasing medium such as carbon dioxide (CO2) or neodymium, an optical cavity consisting of reflective mirrors, and a delivery device that also uses aligned mirrors or fiber optic cables. For CO2 lasers, the mirrors allow for adjustment of spot size to facilitate desired tissue effect. The water within the tissue absorbs the photons from the laser beam and is vaporized, ablating the tissue. Special precautions should be taken when using the laser. The heat generated from the laser can potentially cause drapes and towels to catch fire. The CO2 laser beams can cause corneal damage, and protective eyewear should be worn. Masks with filtering capacity for particulate matter 2 to 5 μm in size should be worn to prevent the potential risk of transmission of human immunodeficiency virus or human papillomavirus in the plume. Constant smoke evacuation is necessary.
Clinically, in gynecologic applications, the CO2 laser has been used extensively for ablation of endometriosis lesions and lower genital tract lesions. In the setting of ovarian cancer, cytoreductive efforts toward no gross residual disease in the primary and recurrent setting have demonstrated in retrospective studies and meta-analyses to offer the best survival for patients. Some retrospective and small prospective studies suggest a benefit to using the laser in aiding the removal of all gross disease without significant increase in complication rates. This benefit included removal of miliary disease (< 1.5 cm) on peritoneal and diaphragmatic surfaces as well as bowel serosa and mesentery, potentially facilitating optimization for intraperitoneal chemotherapy. Operative time for the laser ablation was reported in terms of minutes of application with minimal blood loss, and the laser is extremely useful in anatomically challenging areas such as the porta hepatis and hepatic veins.
Cavitron Ultrasonic Surgical Aspirator
The Cavitron Ultrasonic Surgical Aspirator (CUSA) (ValleyLab) is another surgical adjunct that can be used during cytoreduction of advanced-stage ovarian cancers. The CUSA handpiece encloses a hollow titanium tube that vibrates at high frequency in a longitudinal axis; the variable amplitude of longitudinal vibration determines the depth of tissue disruption when the handpiece is placed in contact with tissue. The handpiece also contains an irrigation and aspiration system to remove tissue fragments and reduce heat buildup. The extent of tissue disruption is also dependent on the water content of the target tissue, with the CUSA causing relatively greater damage to tissue with a high water content (eg, visceral parenchyma, nodal tissue, tumor implants) compared to tissue composed of predominately connective tissue (eg, muscle, ureter, vessel wall adventitia). The CUSA can be used to resect ovarian cancer metastases on the diaphragm, bowel serosa, liver and splenic capsules, and peritoneum. Several reports have cited the efficacy and safety of the CUSA as an adjunctive procedure in achieving optimal cytoreduction in areas inaccessible by more standard surgical techniques. In a prospective trial, the CUSA was associated with lower perioperative blood loss, shorter hospital stay, and less overall morbidity versus when the CUSA was not used during the cytoreductive effort. Although the safety of CUSA has been established in multiple studies, extensive and prolonged use of the CUSA for ovarian cancer cytoreduction should be approached with caution due to the potential for contributing to the development of disseminated intravascular coagulopathy in some patients.
Radiofrequency ablation (RFA) is a minimally invasive technique used to ablate or destroy tumor tissue and is occasionally used in ovarian cancer to cytoreduce intraparenchymal liver implants when liver resection is not feasible or the patient is not a candidate for such an effort. Reports in the literature suggest low rates of optimal cytoreductive efforts with hepatic intraparenchymal involvement, with concomitant decreased survival and need for multidisciplinary surgical approach to the liver resections.4 RFA involves placing a needle probe into the tumor and passing high-frequency alternating current through the probe to increase the temperature of the tumor, resulting in tissue destruction. The procedure has low morbidity (< 5%) and mortality (< 1%) while allowing for rapid recovery and expediting treatment with systemic chemotherapy. Complications include thermal injury to adjacent structures like stomach and colon, portal vein thrombosis, biliary tract fistula or strictures, and hemorrhage requiring surgical intervention.
Choosing the right surgical needle depends on the type of tissue that is being sutured, accessibility to the tissue, size of suture material, and cosmetic factors. The purpose of surgical needles is to guide suture through tissue while causing minimal injury. Three essential properties of a needle guide its performance: its strength, its malleability, and its sharpness. The needles are manufactured from stainless steel, resist corrosion, and are easily made sterile. Surgical needles are divided into 3 areas, called the point, body (portion grasped by the needle clamp), and shank, which contains the eye. Most commonly, for ease of handling and maintaining, the shank lacks an eye, and instead, the suture is swaged to the shank as a continuous unit. There are also controlled-release sutures, also known as pop-offs, that allow the separation of suture from the needle; these are often used during hysterectomy while securing vascular pedicles. Needles with an open eye for threading are seldom used primarily because of the added inconvenience in handling and need to match the needle to the suture size. They are still sometimes used in vaginal surgery during a Burch suspension or uterosacral ligament fixation.
There are generally 2 needle shapes: curved and straight. The curved needles are called by their curvature: 1/4 (used in microsurgery), 3/8 (vascular pedicles, skin), or 1/2 (fascia or deep body cavities) circle. Their size is reflected by the depth of the wound and the suture size needed, with larger needles corresponding to larger sutures. The needle point is designed for the type of tissue handling required. The points are categorized as conventional cutting, reverse cutting, and round or tapered, depending on their cross-sectional shape. The reverse cutting needle has its cutting edge on the outside, allowing the needle edge to pass away from the wound and resulting in less tendency for the suture to tear through tissue. The round needles are ideal for fascial closure because they tend to leave small holes that resist tearing. The blunt tips were designed to supplement the tapered suture while minimizing needle stick injuries but require more precise tissue placement. The straight Keith needle uses a cutting point and is useful for rapid skin closure of abdominal wounds.
For the surgeon, the choice of suture material depends on its purpose (ie, fascial closure, securing vascular pedicles, or skin reapproximation). In addition, wound closure and healing depend significantly on patient characteristics such as age, tissue, location of the wound, and medical conditions such as diabetes or steroid use that contribute to postsurgical complications such as infection, seroma, dehiscence, and hernia formations. Incisional hernias occur more often in women than men and are difficult to treat. This incidence can vary from 9% to 20%. Risk factors for incisional hernias include obesity; older age; medical comorbidities such as diabetes, corticosteroid use, or chronic pulmonary disease; malnutrition; and ascites, all which increase intra-abdominal pressure. Excessive tension on the closure and postoperative infection can lead to poor or inadequate healing; delayed complications such as pain, bowel obstruction, incarceration (6%-15%), and strangulation (2%) necessitating repeat surgical measures; and increased risk of recurrence. Incisional hernias can also enlarge over time, leading to loss of abdominal domain with its potential respiratory dysfunction. Prevention of this complication should be considered the primary goal. Incidentally, small prospective studies in the repair of incisional hernia suggest that laparoscopic approaches yield decreased recurrence and complication rates (specifically infections) versus an open approach.
Historically, there were few surgical options for wound closure. From catgut, silk, and cotton, there is now an ever-increasing array of sutures, including antibiotic-coated and knotless sutures. There are often multiple choices available, and surgeon preference and experience with the material will guide this choice. An ideal suture material and method would prevent dehiscence, pain, infection, and suture sinus and incisional hernias. It is imperative that the surgeon understand the physical properties and tissue handling of the suture material (strength, durability, ease of handling, and resistance to infection)5 as well as appreciate the dynamics of wound healing. The surgeon must use evidence-based data that were available to select fascial closure technique and suture material to minimize potential complications. Although extremely complex, traditionally wound healing has been described in 3 phases: hemostasis and inflammation (injury to days 4-6), proliferation (day 4-2 weeks), and maturation and remodeling (1 week-1 year.) It is in the last phase when ordered collagen deposition increases, translating to increasing tensile strength in the wound. According to Douglas, abdominal wounds will achieve 50% of normal strength at 2 months, 65% at 4 months, and between 60% and 90% at 1 year.6 Wounds will never regain their full strength (Figures 23-7and 23-8 and Table 23-1).
FIGURE 23-7. Wound matrix deposition over time. Fibronectin and type III collagen constitute the early matrix. Type I collagen accumulates later and corresponds to the increase in wound-breaking strength. (Reproduced, with permission, from Witte MB, Barbul A. General principles of wound healing. Surg Clin North Am. 1997;77:509-528.)
FIGURE 23-8. Healing of laparotomies. (Reproduced, with permission, from Rath AM, Chevrel JP. The healing of laparotomies: Review of the literature. Part 1. Physiologic and pathologic aspects. Hernia. 1998;2:145-149.)
Table 23-1 Absorption Rates of Absorbable Sutures
The preferred suture material for laparotomy closure should maintain at least half of its strength during the 4 or 5 months following operation. The choice of suture material and closure technique play a large part in the complications and concomitant comorbidities encountered such as fascial dehiscence, fistulas, infection, hernia formation, incisional/chronic pain, and scarring. This has to be balanced with closure methods that are facile, efficient, and secure. Several meta-analyses have demonstrated that the simple mass closure technique of fascial closure such as a looped 1-0 polydioxanone (PDS) suture as opposed to a layered closure has shown reduction in dehiscence (3.8%-0.8%) and suture sinus formation while being technically easier and taking less operative time. In our experience, the looped PDS has been a reliable suture for the mass closure of vertical incisions, offering all the advantages described in the following sections. Also, in the recent INLINE systematic review and meta-analysis, there was an increased rate of incisional hernias (12.6% vs. 8.4%), with odds ratio of 0.59 (95% confidence interval, 0.43-0.82; P< .001), with continuous versus interrupted suture closures. However, rates of wound dehiscence (1.6% vs. 2.6%), suture sinus (0% vs. 1.7%), wound infection (8.0% vs. 4.1%), and wound pain (1.2% vs. 1.7%) were not statistically significant when comparing continuous versus interrupted techniques.7
General Characteristics of Suture Materials
As mentioned, an ideal suture would have the following characteristics: ease of handling, high tensile strength, minimal tissue reaction and injury, favorable absorption properties, resistance to infection, and ability to hold a knot securely. However, given the heterogeneity of tissue composition and differences in requirements for wound closure, different suture characteristics are necessary. The following are general characteristics that pertain to categories useful to consider in surgical cases.
There are 2 standards currently in use to describe suture size: the US Pharmacopoeia (USP) classification system, established in 1937 for standardization and comparison of suture materials, and the European Pharmacopoeia (EP). The USP system is more commonly used or listed. There are 3 classes of sutures generally used: collagen, synthetic absorbable, and nonabsorbable. Size refers to the diameter of the suture strand and is denoted by zeroes. The more zeroes characterizing a suture size, the smaller the resultant strand diameter (eg, 2-0, or 00, is larger than 4-0, or 0000).
Tensile strength is the measured force required force to break the suture usually and is measured in pounds or kilograms of force. There is a direct relationship between the suture size and tensile strength. The larger the suture size is, the greater the tensile strength of the strand. Suture material should have, and maintain, adequate tensile strength for its specified purpose, which is to prevent disruptive forces during wound healing.8 Smaller sutures with smaller diameters have a higher tendency to tear through tissue, whereas larger strands with more material can lead to increased tissue reactivity. Tensile strength measurements are noted as straight pull or knot-pull, also known as “effective tensile strength,” and measured as the force required to break a strand that has a knot in it. The knot-pull tensile strength is considered to represent true tissue-holding capacity and is always approximately one-third lower than the straight-pull strength.8
Sutures are categorized as absorbable or nonabsorbable, depending on their ability to undergo degradation and absorption via proteolysis or hydrolysis. Most foreign material will to some degree undergo degradation. It as an important characteristic for the suture material to maintain tensile strength to allow for wound healing to take place while undergoing absorption to prevent late complications associated with nonabsorbable materials. Nonabsorbable sutures tend to resist absorption and maintain their tensile strength, whereas absorbable sutures tend to lose most of their tensile strength within 60 days. They are then subclassified into rapidly or slowly absorbed sutures. It should be noted that absorption is a suture characteristic distinct from the rate of tensile strength loss. A suture may display rapid loss of tensile strength yet be absorbed slowly.8 The recent INLINE meta-analysis indicated that slowly absorbable sutures, versus nonabsorbable sutures, had significantly decreased rates of incisional hernias (6.1% vs. 26.3%) and suture sinus (0% vs. 9.0%). With regard to slowly versus rapidly absorbable sutures, a decreased rate of incisional hernias was seen with slowly absorbable sutures (8.1% vs. 10.8%). There were no statistically significant differences in wound dehiscence, infections, or pain.7
Multifilament Versus Monofi lament
Multifilament sutures are constructed from more than 1 fiber by braiding (eg, polyglycolic acid [Dexon] and polyglactin 910 [vicryl]) or twisting (eg, plain or surgical gut) the strands together. Monofilament sutures, such as nylon and PDS, are made from a single strand of material. Multifilament sutures do not offer significant advantage from a wound healing aspect. Their enhanced capillarity and fluid absorption make them more prone to the transport and spread of infection. Because of their construction, they tend to have a rougher surface, leading to an increased drag coefficient, causing microtrauma as they are pulled through tissue and inciting an inflammatory response. All vicryl and Dexon sutures are now manufactured with a coating of lubricant to enhance their handling and performance. Generally, multifilament sutures tend to exhibit a better “stiffness” and “flexibility” profile compared with monofilaments, which also provides better knot security. It is counterintuitive that monofilaments exhibit characteristics opposed to those possessed by multifilament sutures. Their main disadvantage is their stiffness and elasticity, which requires multiple knots to be placed for securing the suture in tissue. Nylon’s high memory has a tendency to loosen the knot, whereas polypropylene’s (Prolene) plasticity, the capacity to be permanently molded or altered, could potentially loosen the suture in tissue undergoing expansion with edema. Their significant inertness, however, makes them desirable.
Historically, the number of suture materials that were available was quite limited. Collagen, from sheep or cow intestine, and silk sutures were dominant prior to World War II. With advances in polymer chemistry, new synthetic fibers were discovered, leading to nylon, polyester, and polypropylene sutures. However, these were nonabsorbable sutures. It was not until the 1970s that synthetic absorbable sutures were introduced that possessed improved and reliable tensile strength while eliciting less intense tissue reactions. A decade later, in the 1980s, newer polymers were manufactured (PDS and polyglycolide-trimethylene carbonate [Maxon]) that had adequate handling characteristics while being absorbable and monofilaments.7 More than a decade ago, new absorbable monofilament sutures were developed constructed with segmented block copolymers consisting of soft and hard segments, such as poliglecaprone 25 (Monocryl); these sutures have better handling, maintaining their tensile strength while reducing absorption rates (see Table 23-1). Recent addition of the barbed suture to the list of available suture materials, such as the barbed PDS (PD0), offers the potential for a knotless suture with improved strength profile across the incision, decreased tissue reaction, and improved operative times. It is an expensive suture to use, and more experience needs to be gleaned for its applicability.
Basic knot tying skill is essential. Techniques include 2-handed or single-handed methods as well as an instrument tie. As we have mentioned, the knot decreases the tensile strength of the tie being placed. Use of synthetic monofilament sutures also decreases knot security and increases possible slippage, requiring extra throws to ensure a secure knot. Regarding knot strength, sliding knots with extra throws are as secure as square knots, and surgeon’s knots are no more secure than square knots for smaller diameter sutures.
Fluency in surgical techniques implies an understanding of the advantages and limitations within the arsenal of surgical instruments at the surgeon’s disposal. Nothing is more essential than a preplanned case with instruments immediately available to the surgeon. Recent developments in instrument technology have been important in reducing operative time and surgical morbidity, but these should not be substitutes for a comprehensive knowledge of basic surgical skills.
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