Principles of Surgery

Developing a Surgical Diagnosis

The important decisions concerning a surgical procedure should be made well before the administration of anesthesia commences. The decision to perform surgery should be the result of careful patient examination. In the critical thinking analytic approach the surgeon first identifies the various signs and symptoms and relevant historical information; then, using available patient and diagnostic data and logical reasoning based on clinical experience, the surgeon establishes the relationship between the individual problems for which surgical intervention may be indicated.

The initial step in the presurgical evaluation is the collection of accurate and relevant data. This occurs through patient interviews and physical, laboratory, and imaging examinations. It may include the use of consultants. Patient interviews and physical examinations should be performed in an unhurried, careful manner. The surgeon should not be willing to accept incomplete data such as a poor-quality radiograph, especially when it is probable that additional data might alter decisions concerning surgery.

For proper analysis, diagnostic data must be organized into a form that allows for hypothesis testing; that is, the dentist should be able to consider a list of possible diseases and eliminate those unsupported by the patient data, disease frequencies, and evidence-based science. By using this method, along with the knowledge of disease probabilities, the surgeon is usually able to reach a decision about whether surgery is indicated and what procedure to perform.

Clinicians must also be thoughtful observers. Whenever a procedure is performed, they should reflect on all aspects of its outcome to advance their surgical knowledge and to improve future surgical results. This procedure should also be followed whenever a clinician is learning about a new technique. In addition, a clinician should practice evidence-based dentistry by evaluating the purported results of any new technique by weighing the scientific merit of studies used to investigate the technique. Frequently, scientific methods are violated by the unrecognized introduction of a placebo effect, observer bias, patient variability, or use of inadequate control groups.

Basic Necessities for Surgery

Little difference exists between the basic necessities required for oral surgery and those required for the proper performance of other aspects of dentistry. The two principal requirements are (1) adequate visibility and (2) assistance.

Although visibility may seem too obvious to mention as a requirement for performing surgery, clinicians often underestimate its importance, especially when the unexpected occurs. Adequate visibility depends on the following three factors: (1) adequate access, (2) adequate light, and (3) a surgical field free of excess blood and other fluids and debris.

Adequate access not only requires the patient's ability to open the mouth widely but also may require surgically created increased exposure. Retraction of tissues away from the operative field provides much of the necessary access. (Proper retraction also protects tissues being retracted from being accidentally injured, such as by sharp instruments.) Improved access is gained by the creation of surgical flaps, which are discussed later in this chapter.

Adequate light is another obvious necessity for surgery. However, clinicians often forget that many surgical procedures place the surgeon or assistant in positions that block chair-based light sources. To correct this problem, the light source must continually be repositioned, or the surgeon or assistant must avoid obstructing the light. The availability of more than one overhead light or using a headlight greatly improves illumination of the operative site.

A surgical field free of fluids and debris is also necessary for adequate visibility. High-volume suctioning with a relatively small tip can quickly remove blood and other fluids from the field.

As in other types of dentistry, a properly trained and focused assistant provides invaluable help during oral surgery. The assistant should be sufficiently familiar with the procedures being performed to anticipate the surgeon's needs. Successful surgery is difficult to accomplish with poor or no assistance.

Aseptic Technique

Aseptic technique is used to minimize wound contamination by pathogenic microbes. This important surgical principle is discussed in detail in Chapter 5 .

Incisions

Many oral and maxillofacial surgical procedures necessitate incisions. A few basic principles are important to remember when performing incisions.

The first principle is that a sharp blade of the proper size and shape should be used. A sharp blade allows the surgeon to make incisions precisely, without causing unnecessary injury caused by repeated strokes. The rate at which a blade dulls depends on the resistance of tissues through which the blade cuts. Bone and ligamental tissues dull blades much more rapidly than does buccal mucosa. Therefore the surgeon should change the blade whenever the scalpel does not seem to be incising easily.

The second principle is that a firm, continuous stroke should be used when incising. Repeated, tentative strokes increase the amount of damaged tissue within a wound and the amount of bleeding; these impair wound healing and visibility. Long, continuous strokes are preferable to short, interrupted ones ( Fig. 3.1A ).

The third principle is that the surgeon should carefully avoid accidentally cutting important structures when incising. Each patient's microanatomy is unique. Therefore to avoid unintentionally cutting large vessels or nerves, the surgeon must incise only deeply enough to define the next major layer when making incisions close to where major vessels, ducts, and nerves run. Vessels can be more easily controlled before they are completely divided, and important nerves can usually be freed from adjacent tissue and retracted away from the area to be incised. In addition, when using a scalpel, the surgeon must remain focused on the location of the blade to avoid inadvertently cutting structures such as the lips when moving the scalpel into and out of the mouth.

The fourth principle is that incisions through epithelial surfaces that the surgeon plans to reapproximate should be made with the blade held perpendicular to the epithelial surface. This angle produces squared wound edges that are easier to reorient properly during suturing and are less susceptible to necrosis of the wound edges as a result of wound edge ischemia (see Fig. 3.1B ).

The fifth principle is that incisions in the oral cavity should be properly placed. Incisions through attached gingiva and over healthy bone are more desirable than those through unattached gingiva and over unhealthy or missing bone. Properly placed incisions allow the wound margins to be sutured over intact, healthy bone that is at least a few millimeters away from the damaged bone, thereby providing support for the healing wound. Similarly, when possible, incisions over prominences such as the canine eminence are best to avoid because the pressure on the closed wound from the prominence may interfere with wound healing. Incisions placed near the teeth for extractions should be made in the gingival sulcus, unless the clinician thinks that it is necessary to excise the marginal gingiva or to leave the marginal gingiva untouched.