only by skin, platysma, and deep cervical fascia. The hypoglossal nerve is also located within the carotid triangle [4, 22].

The posterior triangle of the neck is bounded anteriorly by the sternocleidomastoid muscle, posteriorly by the anterior trapezius muscle, and inferiorly by the clavicle. Deep to the posterior triangle lay the splenius capitus, levator scapulae, and scalene muscles in addition to the brachial plexus. These structures are invested by deep cervical fascia. The spinal accessory nerve is especially susceptible to injury within this triangle. It exits the skull via the jugular notch, traveling deep to the sternocleidomastoid muscle and emerges at Erb’s point, traveling over the posterior triangle to innervate the trapezius muscle. Erb’s point may be estimated by drawing a horizontal line from the thyroid notch to the posterior border of the sternocleidomastoid muscle. The region spanning 2 cm above and 2 cm below this point and running the horizontal length of the posterior triangle denotes the danger zone where the nerve is most likely to be injured. Clinically, if the spinal accessory nerve is injured, the patient will have difficulty abducting the arm, chronic shoulder pain, and difficulty shrugging the shoulder. It should also be

noted that the transverse cervical nerve, a branch of C2 and C3 which provides sensory innervation to the anterolateral neck, as well as lesser occipital and great auricular nerves, exits from beneath the sternocleidomastoid muscle near Erb’s point and is relatively susceptible to injury within the posterior triangle [1, 22].

Summary: Conclusion

•Cranial nerve VII is responsible for providing motor innervation for the muscles of facial expression.

•Cranial nerve V contributes sensory innervation to the face and a portion of the scalp.

•Muscles of facial expression allow mankind to communicate nonverbally.

•Injury to motor nerves in the head or neck may lead to consequences such as facial asymmetry, difficulty in pronunciation, inability to protect vital structures such as the eye, or restricted limb movement.

30.8Conclusion

In conclusion, the anatomy of the head and neck is an intricate, complex network, and adequate knowledge of anatomic structures is critical for anyone performing surgical or cosmetic procedures in these regions. The deeper structures of the head and neck were reviewed in this section including the motor and sensory nerves, muscles, bony and cartilaginous structures, fat, fascia, and mucosa. Cranial nerve VII is responsible for providing motor innervation for the muscles of facial expression. The fifth cranial nerve, or trigeminal nerve, contributes a majority of the sensory innervation of the face and a portion of the scalp. Mankind’s ability to communicate nonverbally may be attributed to the muscles of facial expression, and the overall structure of the face is largely determined by the underlying bony and cartilaginous skeletons as well as subcutaneous fat. Injury to motor nerves in the head or neck may lead to consequences such as facial asymmetry, difficulty in pronunciation, inability to protect vital structures such as the eye, or restricted limb movement. Loss of adipose tissue may have various cosmetic implications. Familiarity with these structures will allow one to more adequately counsel patients about risks and benefits of procedures.

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A.A. Ingraffea (*) • H.M. Gloster Jr.

Department of Dermatology, University of Cincinnati, Cincinnati, OH, USA

e-mail: ingrafam@ucmail.uc.edu

Summary: Bleeding Complications

•Serious bleeding complications are rare in Mohs surgery.

•Discontinuation of anticoagulant medication is not necessary and is not generally recommended.

•Serious and even fatal thrombotic complications have been reported to occur after the discontinuation of medically necessary blood thinners.

31.1Bleeding Complications

Bleeding complications can take the form of excessive or undesired bleeding as well as the opposite problem of unintended thrombosis. As many of our patients are elderly and are routinely prescribed multiple anticoagulants (e.g., aspirin, clopidogrel, coumadin, and heparin), it is important to be aware of the current recommendations for anticoagulant management as it relates to Mohs surgery. In addition, more and more patients are taking over the counter medicines which may also increase the risk for surgical bleeding. Therefore, the first step to successfully preventing a bleeding complication is a thorough medical history with specific emphasis on the patient’s medications.

Most surgical bleeds occurring during Mohs surgery are relatively minor and easily controlled with pinpoint electrocoagulation or primary ligation of a transected vessel. In order to avoid unnecessary sectioning of a larger artery it is important to be familiar with the major arteries which may be encountered during a surgical procedure. The most commonly transected major vessels in the face are the superficial temporal artery and branches of the facial artery. The superficial temporal artery is the terminal branch of the external carotid artery, and it is easily palpated superior and anterior to the tragus. As it travels in an ascending course over the zygoma it bifurcates into an anterior and parietal branch. Above the zygoma it lies within the thin subcutaneous fat of the anterior scalp.

The facial artery branches off the external carotid artery and crosses over the mandible anterior to the masseter muscle where it can be palpated. As it crosses the mandible the facial artery is covered by the platysma and risorius muscles. The artery then courses in a diagonal and superior direction, giving off the inferior and superior labial arteries. The artery travels up towards the medial canthus where it anastamoses with the dorsal nasal artery, a branch of the internal carotid artery. When transected, most named arteries should be clamped and ligated (Fig. 31.1).

In addition to the brisk bleeding of a transected artery, the Mohs surgeon must also deal with the oozing of small vessels and capillaries. This oozing can be especially frustrating when surgery is performed on patients taking anticoagulants, especially aspirin. Anticoagulant use is the most common cause of persistant intraoperative bleeding, if the surgeon fails to respond adequately with meticulous hemostasis this

Fig. 31.1 Large transected vessels should be clamped and ligated

Fig. 31.2 Hematoma on the arm of a patient taking Plavix and aspirin

can lead to the formation of a postoperative hematoma (Fig. 31.2). The list of anticoagulants encountered continues to grow, including both prescription and over-the-counter medications.

While it is tempting from a convenience point of view to have patients discontinue their anticoagulant medications, in most cases, this is not to be

recommended. Patients taking aspirin for pain or inflammation may safely stop taking the medications for 7 days prior to surgery and restart several days after surgery, nonsteroidal anti-inflammatory drugs (NSAIDs) can be stopped 3 days prior to surgery since they have less profound effects on platelet aggregation. In addition, herbal supplements such as Vitamin E, the four G’s (ginko, ginseng, ginger, garlic), and fish oil, among others, should be stopped prior to surgery. The most important question remains, should patients stop taking medically indicated anticoagulants prior to Mohs surgery? There have been seven published studies which have investigated this issue. The largest study to evaluate the effect of taking a single anticoagulant agent involved 653 patients [1]. This study found a small, 1.6% versus 0.7%, but statistically insignificant increase in serious bleeding in the group taking either aspirin, warfarin, or NSAIDs when compared to controls. The largest study to date examined 760 consecutive patients in an academic Mohs practice and compared the bleeding complications between patients taking no anticoagulants, one anticoagulant, and two or more anticoagulants [2]. The study concluded that the use of two or more anticoagulants increased the risk of serious bleeding when compared to one or no anticoagulant. However, the study reported only four events of serious bleeding so it may be underpowered to detect differences between the three groups. In another study of 96 patients taking either warfarin or no warfarin there was significantly more minor bleeding in the warfarin group (26%) versus the no-warfarin group (6%); however there were no serious bleeding events in either group [3].

Kargi et al. evaluated 102 patients taking either aspirin, warfarin or no anticoagulant and found that aspirin was not associated with an increased risk of bleeding complications [4]. However, an increased risk of serious bleeding complications was noted in patients taking warfarin. The definition of serious complication in this study may have been too broad as it included wound infection and loss of skin graft as well as hematoma and persistent bleeding. This article reported five serious complications in the warfarin group and none in the aspirin or control groups. The authors did not provide detailed information on the type of serious complication encountered, so it is difficult to attribute all these to the use of warfarin. For example, a skin graft may fail due to a poor wound bed or improper suturing technique, and wound infections may occur

for many reasons that have nothing to do with the use of warfarin. Finally, in a prospective study of 322 patients taking aspirin, warfarin, NSAIDs, or no anticoagulant, Billingsly et al. found no statistically significant increase in patients taking anticoagulants [5].

In order to ascertain what can be learned from the currently available studies, Lewis et al. performed a meta-analysis of studies published between 1966 and 2005 [6]. A total of 1,373 patients met the criteria for study inclusion. The analysis revealed that patients taking warfarin were seven times more likely to suffer a moderate to severe complication than the control group. However, this conclusion is not entirely beyond reproach. In the warfarin group of the meta-analysis, there were a total of 122 patients, with 7 experiencing severe complications. Of these 7 patients, 5 were from the previously described study by Kargi et al. which failed to limit severe complications to bleeding alone, but also included infection and loss of skin graft. The meta-analysis also concluded that patients taking aspirin or NSAIDs were twice as likely to suffer serious bleeding complications, but this finding did not meet statistical significance. The study did not evaluate the effects of taking multiple anticoagulants on bleeding complications. It seems likely, therefore, that the risks of serious bleeding complications in patients, who undergo Mohs surgery, are small but may be slightly increased especially when taking warfarin.

In spite of the apparent low risk associated with continuing anticoagulant therapy, many surgical dermatologists still discontinue medically necessary anticoagulants. A survey of Mohs surgeons performed in the year 2005 found that 37% discontinue medically necessary aspirin and 44% discontinue medically necessary Coumadin [7].

If it is accepted that anticoagulants pose a small but manageable risk to the patient undergoing a Mohs procedure, what are the risks associated with the discontinuation of these medicines? Kovich et al. surveyed 168 members of the American College of Mohs Micrographic Surgery about thrombotic events occurring in the perioperative period in patients who had discontinued their anticoagulation [8]. A total of 46 thrombotic events were reported, of these 54% occurred after discontinuing warfarin and 39% after discontinuing aspirin. The most common thrombotic event reported was stroke, followed by TIA and MI. A total of three deaths were reported. The authors were able to estimate to incidence of thrombotic events and calculate