Summary: Information for Patients

•While Mohs surgery has a very low rate of complications, there are still some important safety considerations for patients to consider preoperatively.

•Cardiovascular complications can be related to discontinuation of anticoagulants as well as use of electrosurgery in the presence of implanted cardiac devices.

•Antibiotic prophylaxis is important for select patients, but is likely unnecessary for routine use in all patients.

•Local anesthesia surgery has many advantages, but physicians and patients should be aware of its limitations.

44.3Information for Patients

44.3.1 Cardiovascular Complications

Mohs micrographic surgery is an inherently safe procedure with few major complications or cardiovascular events. While there have been reported thrombotic events during or immediately after Mohs surgery, these are often associated with discontinuation of anticoagulant medications [2, 3]. Such medications include warfarin (Coumadin), heparin, aspirin, and clopidogrel (Plavix). Commonly, patients inquire about stopping their anticoagulation medications prior to surgery, as they may assume that these medications predispose them to bleeding complications during surgery. However, patients should be informed that the decision to stop anticoagulant medications must not be taken lightly, as this discontinuation may predispose them to thromboembolic complications. Recommendations concerning anticoagulants in dermatologic surgery have been published, and they are summarized later in the chapter.

Additional cardiovascular issues involve pacemakers and implantable cardiac devices (ICD), and these are also useful to share with patients. These devices are becoming increasingly common in the treatment of cardiac disease. It is not uncommon to encounter patients with these devices needing electrosurgery at the time of Mohs surgery. Although technological improvements have made the implantable devices

more resistant to electromagnetic interference, there still is a risk of potentially serious consequences [4–7]. Electrosurgery can cause implanted cardiac units to malfunction through several different mechanisms, including reprogramming, battery depletion, or direct damage to the device [8, 9]. Likewise, electrosurgery can stimulate other implanted electrical devices, such as central nervous system (CNS) devices.

It is a good habit to screen for the presence of an implanted cardiac (or neurological) device during the preoperative history and physical. If a pacemaker, ICD, or nerve stimulator is in fact present, a Mohs surgeon can follow recommended precautions that have appeared in the dermatologic literature [4]. In selected patients with cardiac disease, these precautions can include obtaining a baseline electrocardiographic study prior to surgery. Such testing can screen for pacemakerdependent patients, who may be unable to tolerate unit malfunction from electromagnetic interference. Additional recommendations include the use of bipolar forceps, which may cause minimal interference, and/or electrocautery (heat cautery), which causes no interference [8, 10–12]. If the latter options are not available, another recommendation is to avoid the use of electrosurgery within 15 cm of the device, using short bursts of electricity, placing grounding plates as far from the device as possible, using minimal power, and avoiding cutting current, which is more likely to cause interference [4]. A final option is that the device in question can be turned off for the procedure and then reactivated after the procedure is completed. In the authors’ experience, the latter approach is not as effective for nerve stimulators, as it can lead to uncontrolled muscle tremors.

Published recommendations regarding cardiac devices include the suggestion that patients have preoperative and postoperative cardiology evaluation if electrosurgery is used, while others have suggested that such evaluation is made unnecessary by using only electrocautery (heat cautery) or bipolar forceps for hemostasis during the procedure [4, 8, 10–12]. If the surgeon has any doubt about the status of the implanted device during surgery or should the patient have any cardiac related symptoms, postoperative interrogation of the unit can help rule out damage to the device.

In any case, as with most patient safety issues, it is wise to have a protocol in place should a patient with an implanted cardiac or neurological unit need surgical care. Such protocols may help identify patients who

need to obtain cardiology or neurological consultations and can ensure that the office has the requisite equipment to facilitate patient safety during the surgery day. For such situations, the authors find it helpful to always have ready-to-use bipolar forceps and cords as well as new, disposable electrocautery (heat cautery) units.

44.3.2 Antibiotic Prophylaxis

Mohs surgery is best considered to be a clean or cleancontaminated procedure rather than a sterile procedure [13, 14]. After all, during Mohs surgery, patients undergo serial rounds of excisions and bandaging and often leave the surgical area while the tissue is being processed. This is very different from traditional sterile technique in the operating room. Frequently questions arise from patients about the need for antibiotics. Therefore, during the preoperative visit, it is helpful to inform patients about the low infection rates of Mohs

surgery. It may be useful to discuss studies like the one performed by Maragh and Brown, which prospectively evaluated 1,000 consecutive patients undergoing Mohs surgery without postoperative antibiotics [15]. That study reported a surgical site infection rate of 0.7%. This low rate of infection is excellent and is more consistent with “clean” procedures, in which a 1–3% infection rate is acceptable [16].

Simultaneously, in the preoperative visit, the surgeon can screen for any conditions that may warrant the use of antibiotics. A recent advisory statement regarding indications for antibiotic prophylaxis in dermatologic surgery was published by Wright et al. in the Journal of the American Academy of Dermatology in 2008 [17]. It was based on the updated guidelines of the American Heart Association, the American Dental Association, with the American Academy of Orthopaedic Surgeons. It details antibiotic prophylaxis for the prevention of infective endocarditis, hematogenous total joint infection, and surgical site infection

Table 44.2 Antibiotic recommendations for prophylaxis of endocarditis and hematogenous total joint infection in dermatologic surgery

Data adapted from reference [17]

aAll are single dose, given 30–60 min preoperatively bAlternate medication for penicillin allergic patients

Table 44.3 Antibiotic recommendations for prophylaxis of surgical site infection

Data adapted from reference [17]

aAll are single dose, given 30–60 min preoperatively. However, may consider extended course of antibiotic treatment (e.g., 1 week, in addition to preoperative dose) for patients at high risk bAlternate medication for penicillin-allergic patients

for patients with an increased risk for developing these infections. Drawing on recent evidence, the authors outline the types of patients and procedures that would benefit from antibiotic prophylaxis (summarized as part of Tables 44.1–44.3). While this publication indicates that routine, prophylactic administration of antibiotics for all skin surgery is likely unnecessary, it is also just a guideline, and the Mohs surgeon should take the unique characteristics of each case into account when making antibiotic prophylaxis decisions.

44.3.3 Anticoagulation

Patients taking some form of blood-thinning agent, either as a prescribed medication or an herbal supplement, are

Table 44.4 Anticoagulant medications

common to dermatology surgery practices (Table 44.4). In a careful history and physical, the surgeon can uncover use of these agents. Patients often inherently understand that blood thinners predispose them to some degree of prolonged bleeding, and can express concern about the use of these medications during surgery. Also, given the choice, many surgeons would likely prefer to work on patients with normal blood clotting functions. So there may be temptation by physicians and patients alike to temporarily discontinue the anticoagulant medication(s).

However, the decision to stop any medically necessary anticoagulants should not be taken lightly. As mentioned previously, it is very helpful to inform patients that stopping their anticoagulants is not a riskless endeavor. Kovich and Otley investigated thrombotic complications related to discontinuation of warfarin and aspirin therapy for dermatologic surgery procedures. They uncovered thrombotic events and even deaths related to simply the cessation of aspirin, and found them to be comparable to the adverse events related to the cessation of warfarin [18]. This finding was particularly interesting and contradicted the previous reports that suggested that stopping aspirin was not associated with the complications of stopping warfarin [19]. Additionally, for cutaneous surgery such as Mohs, ample evidence indicates that there is no significant increased frequency and or severity of bleeding complications in patients taking blood thinners [20–24].

Taken together, this information suggests that the risks of routine discontinuation of medically necessary blood thinners for dermatologic surgery likely exceed any potential benefits. This is especially true with Mohs surgery, and patients should be counseled

preoperatively on this subject. Many patients taking these medications are older, and may still recall prior, outdated recommendations regarding blood thinners and surgery. As a potential thrombotic complication can be a far greater patient safety hazard than a postoperative bleeding complication, any counseling is time well spent with the patient. After all, most intraoperative and postoperative cutaneous bleeding complications can be managed with pressure, cautery, and/ or vessel ligation. The risk of blood loss severe enough to cause significant morbidity or mortality during Mohs surgery is remote.

However, a patient’s care should be individualized. If a patient’s unique circumstances necessitate the discontinuation of medically necessary blood thinners, it is preferable to work with the prescribing physician to stop and restart the anticoagulants. For non-medically necessary blood-thinning agents, such as herbs (ginko, garlic, etc.), supplements (fish oil, vitamin E, etc.), or aspirin taken purely for preventative purposes, the dermatologic surgeon may choose to recommend that the patient forgo taking them 10–14 days prior to the procedure and then 5–7 days postoperatively [25].

44.3.4 Anesthesia

Mohs surgery and subsequent reconstruction are commonly performed using only local anesthesia, and patients are usually informed of this at the preoperative visit. Patients have become accustomed to the idea of surgery under local anesthesia, and in fact, often express relief that they will not need general anesthesia. However, there are patients who may not be comfortable with the idea of being awake for any type of surgery. The surgeon would be wise to advise patients of the risks and benefits of local as well as general anesthesia, emphasizing the outstanding safety record of procedures using local anesthesia only.

The safety of office-based surgery under local anesthesia has been the focus of much recent interest and study. Florida and other states have instituted mandatory reporting of office surgery deaths and injuries, and the generated data further supports the superior safety of office-based, local anesthesia surgery [26]. In fact, the complication rate for office-based procedures commonly performed by a dermatologist is reported to be <0.5% [27]. After citing the safety data to patients, the

authors find that patients prefer the local anesthesia option.

The typical local anesthetic employed for most dermatologic surgery, including Mohs, is 0.5–2% lidocaine with epinephrine. For nontumescent anesthesia procedures, such as Mohs surgery, the recommended maximum dosage of lidocaine in adults is 4.5 mg/kg without epinephrine and 7.0 mg/kg with epinephrine. In tumescent anesthesia used for liposuction, the maximum recommended dosage is 35–55 mg/kg [25]. Symptoms of lidocaine toxicity are directly related to the serum lidocaine level, and include, at the early stages, circumoral paresthesia, tinnitus, visual disturbances, slurred speech, and muscle twitching. Finally, seizure, coma, and cardiac arrest occur at high levels of lidocaine overdose [28, 29].

Lidocaine toxicity is a concern during Mohs surgery, especially for larger tumors requiring prolonged procedures. Addressing this issue, Alam et al. prospectively evaluated the serum lidocaine concentration of patients undergoing Mohs surgery [30]. The patients required from 5 to 48 mL of lidocaine 1% with 1:200,000 epinephrine for the procedures. The study patients underwent serial blood draws over a span of up to 8 h to measure peak serum lidocaine concentrations. The highest serum lidocaine level detected at any time for any patient was 0.3 mg/mL. This was far below the threshold for objective signs of lidocaine toxicity such as tinnitus, paresthesias, and muscle twitching, which occurs at about 5 mg/mL, or roughly 16 times the peak levels observed in the study [31]. Seizures, coma, and respiratory arrest typically require even greater serum lidocaine concentrations, typically exceeding 9 mg/mL [28, 29].

If a patient has a history of anxiety surrounding surgical procedures, it is helpful to have an anxiolytic medication, such as lorazepam, available at time of local anesthesia surgery, and to inform patients of this option. Should the anxiolytic be necessary, the patient would generally be advised to avoid operating a motor vehicle and would need to arrange alternative means of transportation.

44.3.5 Allergies

It is very useful to elicit a careful medication allergy history from the patient. The physician must also