Gary Andrew Dildy
According to Ochsner, the knife was the first tool developed by humans, and it is thought to be used as far back as 8,000 BC for the therapeutic purpose of cutting through the skull (1). Harer opined that the first known special-purpose surgical instrument was the Peseshkef, a fish-shaped flint knife used in Egypt circa 5,000 BC to cut the umbilical cord at birth, as well as in “opening of the mouth” ceremonies for mummies to allow nourishment in the afterlife (2). Over the long course of medical history, a multitude of general use and specialty-specific surgical devices have been developed, and thousands remain commercially available today.
Surgical procedures have evolved into complex team efforts. Toward the common goal of optimal patient outcome, it is of vital importance that all members of the surgical team are familiar with the identity and function of available surgical instruments. The surgeon should be particularly aware of the instruments contained in the procedure-specific trays and generally aware of auxiliary devices that are available if needed. The scrub technician and circulating nurse should be aware of the physical location and availability of equipment as required. The surgical assistant likewise should be familiar with the equipment to anticipate surgical steps, provide optimal exposure, and facilitate efficient progression of the procedure.
With ˜4 million annual births in the United States, of which a third are cesarean deliveries, obstetrical procedures are some of the most frequently performed hospital-based surgeries. The majority of currently employed surgical devices have evolved into multiple variations and are referred to by various synonyms and eponyms. Instruments of a specific type may be available in an array of sizes—for example, the ubiquitous Mayo scissors, ranging from 5 to 14 inch lengths—in straight and curved variations. Some instruments are designed for right versus left handedness. Contemporary commercial surgical instrument catalogs contain thousands of individual surgical instruments.
The goal of this chapter is to familiarize the reader with basic surgical instruments generally encountered in the more common obstetrical procedures. Operative vaginal delivery (i.e., obstetric forceps and vacuum devices) and fetal surgery (e.g., fetoscopic laser ablation for twin-twin transfusion syndrome and in utero meningomyelocele repair) will be addressed separately in Chapters 4.4 and 3.10, respectively. In this chapter, surgical instruments will generally be categorized as:
Cutting and dissecting
Retracting and exposing
Grasping and holding
Recognizing that there are many commercially available single-use (i.e., disposable) surgical devices, this chapter primarily focuses on universal reusable hardware.
CUTTING AND DISSECTING
To many surgeons, the scalpel is eponymously referred to as the “Bard-Parker” knife. The development of the modern scalpel dates back a century to 1915, when Morgan Parker, an engineer, received a patent on a two-piece scalpel, in which the metal blade and handle were attached by overlapping parts (1). With Charles Bard, a manufacturer, he founded the Bard-Parker Company that developed a cold sterilization process to avoid dulling of the surgical blades. Surgical scalpels may be disposable or reusable (i.e., the handle is reusable, and the blade is discarded). Originally, handles were numbered 1 to 9 and blades 10 to 20, but after the patent expired in 1935, other variations followed (3). There are numerous commercially available scalpel handles, the most common being the #3, #4, and #7 handles, shown in Figure 1.2.1. Flat handles (#3 and #4) are generally used with a palmar grip for incisions. The #4 handle is similar to the #3 but somewhat larger. The #7 is long and rounded, generally used with a pencil grip for deeper dissection. There are multiple blade variations, each designed for use with specific handles. The #3 and #7 handles are designed for #10 to 15, 40, and 42 blades, and the #4 handle is designed for #18 to 36 blades. There are various disposable safety scalpels, with plastic handles and extensible blades, designed to prevent accidental injuries.
Scissor blades meet and decussate (i.e., override each other) to cut (4). Surgical scissors are designed to cut tissue, suture, and other materials. Surgical scissors are generally made of stainless steel, and some have tungsten carbide cutting edges. Ring scissors are commonly used in obstetrical surgery, whereas spring forceps (not shown) are used in ophthalmic and microsurgery. Scissor blades can be straight or curved, and the tips are designed in several conformations (i.e., blunt/blunt, sharp/sharp, or sharp/blunt). Most types of scissors are available in various lengths and modifications. Common scissors in obstetrical surgery are shown in Figure 1.2.2. Iris scissors, designed for ophthalmic surgery, are small and have two very sharp points; they are used for small, precision cutting of delicate tissue. Metzenbaum scissors are designed for fine dissection and cutting delicate tissue. The heavier Mayo scissors are used for cutting thicker tissues and surgical materials such as sutures. Bandage scissors have angled tips, the bottom
blade typically flat and blunt to introduce under a bandage avoiding skin damage. For the same reason, bandage scissors are sometimes used for extending hysterotomy incisions during cesarean delivery.
Figure 1.2.1. Scalpels and blades. Scalpel blades on the left, from top to bottom: #10, #15, and #20. Scalpel handles, from left to right: #3, #7, and #4. (© Aesculap AG.)
RETRACTING AND EXPOSING
Adequate visualization of the surgical field is an essential prerequisite for most, but not all (e.g., operative vaginal delivery), surgical procedures. Retractors serve to separate surgical incision margins or to retain organs from the field, both to optimize visualization and access. Retractors may be manual or self-retaining. Some are designed for superficial/shallow exposure and others for deep exposure.
Some common manual shallow retractors are shown in Figure 1.2.3 and deep manual retractors in Figure 1.2.4.
Figure 1.2.3. Shallow manual retractors, from left to right: Richardson-Eastman retractors (small and large), Goelet retractor, US Army retractor (2 per set), and Senn retractor with round tapered handle. (© Aesculap AG.)
Figure 1.2.4. Deep manual retractors, from left to right: Amalleable ribbon spatula, the Richardson retractor, the Deaver retractor, and a Balfour retractor center blade. (© Aesculap AG.)
The Army-Navy retractor is double-ended and has a fenestrated handle.
The Richardson retractor is right-angled, concave with a lip at the tip; the handle is hollow with finger ridges for better grip.
The DeLee universal retractor was designed for postpartum vaginal examination and is often used as a “bladder blade” during cesarean delivery (Figure 1.2.5). Joseph DeLee (1869-1942), founder of the Chicago Lying-In Hospital, is considered a major influence on contemporary obstetrical practice.
Like many surgical instruments, self-retaining abdominal retractors have evolved over the centuries. Use of the self-retaining abdominal retractors in obstetrics is usually limited to laparotomy for peripartum hysterectomy.
The O’Sullivan-O’Connor abdominal retractor (Figure 1.2.6) was introduced by John R. O’Sullivan (1900-1965) and Bernard A. O’Connor (1890-1953) of New Jersey in 1931 (5) as a simple mechanical retractor for abdominal surgery (6). This retractor features an adjustable shape ring, with two fix-mounted side blades on the frame and the option of cephalad and caudad detachable blades.
In 1979, John R. Bookwalter, MD, patented his eponymous table-fixed retractor system, which allows placement of a variety of blades and has been modified for use across multiple surgical disciplines (Figure 1.2.7) (7). The Bookwalter retractor offers three advantages over its predecessors: (1) it attaches to the operating room table from one, as opposed to two sides; (2) it can be attached after draping the patient; and (3) it has a more simplified ratchet system for attaching, adjusting, and removing retractor blades (8).
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