Mohs Micrographic Surgery Indications for Termination

Issues of Concern

Preoperative Indications for Termination

Preoperative indications for MMS termination include patient factors, ethical considerations, or procedural reasons.

Patient factors

Patients who arrive on the day of surgery with factors that preclude them from general fitness for surgery should be rescheduled and redirected to the appropriate site for emergent care. Some situations when MMS should be rescheduled include but are not limited to evidence of acute myocardial infarction, signs of acute stroke, hypertensive urgency or emergency, delirium tremens, acute psychosis, active infections, and renal failure. In general, any life-threatening medical condition that requires further evaluation in an urgent or emergent setting should be a contraindication for proceeding with MMS. However, the procedure may be rescheduled shortly after managing the condition and stabilizing the patient.[6] For patients on anticoagulation therapy with an international normalized ratio (INR) greater than 3.5, a delay in surgery is also prudent, though not an absolute requirement.[7]

Ethical considerations

Challenges also arise when patients cannot consent to surgery due to a lack of decision-making capacity and do not have an appropriate surrogate decision-maker present to consent on their behalf. The appropriate surrogate decision maker should be legally specified in documentation through advanced directives or durable medical power of attorney.[8] MMS is unique as patients may wait several hours from the start to the completion of the case if multiple stages or complex reconstructions are required. Patients with dementia may not be able to tolerate the time needed for the procedure or may face serious challenges owing to their neurologic or psychiatric status.[9] The Mohs surgeon must act in the patient's best interest while adhering to applicable state-specific legislation regarding consent.

Procedural factors

Should a patient be unaware of the site of surgery or unable to identify the correct surgical site, efforts should be made to verify the site with the referral description and photographs. If the surgeon cannot confidently identify the surgical site, the case should be delayed pending further evaluation of the suspicious clinical lesions with more clarification. Proceeding without this certainty may introduce unnecessary risk to the patient, miss residual cutaneous pathology, and result in wrong-site surgery. Likewise, MMS should be halted should a review of the biopsy slide or a debulk specimen prove to be a benign lesion differing from the referral diagnosis. The biopsy slide may be reviewed with the dermatopathologist, or the debulk specimen may be thawed and sent for permanent section analysis to ensure the correct site, diagnosis, and indication for MMS.

Intraoperative Indications for Termination

Intraoperative indications for termination of MMS include the discovery of unresectable disease, reduced patient comfort, patient decompensation, sudden development of severe complications, and injury to the Mohs surgeon or surgical staff.

Unresectable disease

Patients with cutaneous tumors that track into deeper structures, such as the orbit, ear canal, nasal mucosa, anal mucosa, vaginal mucosa, or neck, may not tolerate surgery of these sites under local anesthesia. Thus, referral to the appropriate specialists for general anesthesia may be warranted. However, the necessity of such a measure depends on the Mohs surgeon's level of training.[10] Mohs surgeons should take care to mark the site of residual tumor and document the surgical site with photographs to avoid delays in management and decrease confusion for the receiving specialist.

Tumor invasion of bone also represents a challenge in frozen section evaluation since margins cannot be visualized clearly through osseous sections. The lack of visualization makes clearance of the tumor less certain in the MMS setting, though a pitted appearance may suggest evidence of microscopic bone invasion. When microscopic bony invasion is suspected during the resection of a scalp lesion, burring the skull's outer table may be accomplished with bone fragment evaluation using a decalcification solution.[11] The removal of the periosteum alone or in conjunction with bone chisel or drill use may also pose a risk of cerebral air embolism.[12] The risk of an air embolus is greater when the patient is seated. The signs and symptoms of air embolism include tachypnea, headache, disorientation, and focal neurologic deficits. Bone resection under the scalp may necessitate collaboration with neurosurgery or otolaryngology specialists.

Planning for the possibility of deeper lesional invasion may be helpful. The steps include using preoperative imaging studies and identifying the tumor's histologic subtype. Some cutaneous tumors have a higher likelihood of deeper invasion, including morpheaform basal cell carcinoma, infiltrative basal cell carcinoma, micronodular basal cell carcinoma, invasive squamous cell carcinoma, and dermatofibrosarcoma protuberans. Additionally, termination may be a consideration for positive tumor margins tracking into sites like the anus, as additional stages could result in a loss of function.[13]

Sentinel lymph node biopsy should be considered before MMS to prevent rearrangement of tissue and lymphatic channels. Tumor board referral may also be prudent in locally advanced tumors.

Reduced patient comfort

MMS may also be discontinued when the patient becomes unwilling or unable to proceed with surgery. Such a situation may arise if musculoskeletal pain precludes prolonged surgery. Efforts should be made to reposition the patient to ensure comfort and avoid this possibility. Patients may also require significant amounts of local anesthetic due to prolonged surgery or faster metabolism of the anesthetic agent. Receiving anesthesia beyond maximal thresholds may be an indication to stop the procedure since further anesthesia could risk adverse effects. Typically, for lidocaine, this dose is 3 to 4.5 mg/kg when no vasoconstrictor is used and 6 to 7 mg/kg when a vasoconstrictor is used.[14]

Deeper sites can become difficult to anesthetize, and some tissues with significant scarring are difficult to infiltrate with local anesthesia. Preoperative planning should include a discussion of regional blocks, tumescent anesthesia, anesthetics with longer durations of action, and oral analgesics to avoid the likelihood of surgery termination due to inadequate anesthesia or anesthesia meeting or exceeding the allowable limits safely. Rescheduling for completion or reconstruction is prudent to avoid anesthetic toxicity if suspected. Systemic signs of lidocaine toxicity may progress to seizure or respiratory arrest. Initial manifestations of lidocaine toxicity include perioral numbness, metallic taste, tongue-tingling, slurred speech, tinnitus, nystagmus, fine tremor, and muscular twitching.[15]

Knowing the factors that may increase case complexity or the number of Mohs stages can help plan anesthetic use. Previous treatment with cryotherapy, older patient age, and multiple previous surgeries may increase the need for additional stages. Factors that may increase the procedure's complexity or number of required stages include a treatment delay of more than 180 days, post-solid organ transplant status, ear cancers, and larger tumors.[16]

Patient decompensation

Individuals scheduled for MMS are ideally fit to receive the procedure. However, surgery should be terminated if a patient suddenly develops altered mental status or expresses a preference for discontinuation during surgery. For unresponsiveness, protocols for managing cardiac arrest, symptomatic cardiac arrhythmia, respiratory failure, or acute stroke, as well as basic and advanced cardiac life support, should be promptly initiated. Patients exhibiting symptoms of fatigue, lightheadedness, loss of consciousness, chest pain, palpitations, confusion, and intractable pain should be redirected to the appropriate center for immediate care.[17] Emergencies such as anaphylaxis, anesthetic toxicity, seizure, or shock should also prompt immediate office-based treatment and referral for definitive management by an emergency physician.

Severe complications requiring immediate referral

Severe intraoperative complications may necessitate early MMS termination and immediate referral. For example, an eyelid surgery that results in uncontrolled retrobulbar hemorrhage may be referred to an ophthalmologist for immediate treatment to avoid vision loss.[18][19] The incidence of retrobulbar hematoma associated with eyelid surgery is low, reported to be 0.055% in a study of 2000 patients, and may occur following surgery, especially within the first 3 hours.[20] Immediate treatment of uncontrolled hemorrhage during surgery can also help avoid hemodynamic compromise. Other anatomic areas that can pose bleeding problems in the outpatient setting include the nasal mucosa, vaginal mucosa, and deep tissues of the neck. 

Injury to the Mohs surgeon or surgical staff

Acute injuries to the Mohs surgeon or staff should prompt consideration for termination until additional personnel are available to proceed with the MMS procedure, either to an acceptable stage or full completion. In Mohs surgeons using lasers intraoperatively, laser eye injuries should be referred immediately for ophthalmologic management to reduce ocular inflammation and the risk of vision loss.

MMS termination must also be considered in cases where bloodborne pathogen transmission may occur due to inadvertent exposure to a patient's bodily fluids, such as blood splashes and needlestick injuries. Bloodborne pathogen postexposure prophylaxis should be considered, with coordinated laboratory testing according to site-specific MMS protocols. Bloodborne pathogen exposure in MMS may occur through mucous membrane contact with blood splashes or sharps injuries, the latter of which carry a 7.5% annual risk of bloodborne exposure.[21] Exposure to a bloodborne pathogen in the Mohs surgeon may require patient rescheduling or return for reconstruction to ensure that the exposed individual’s safety and health are prioritized.

Enhancing Healthcare Team Outcomes

MMS is a highly effective and precise treatment for cutaneous neoplasms that rarely requires early termination, but certain preoperative and intraoperative situations may necessitate termination to prioritize patient safety. The Mohs surgeon, with a thorough understanding of the medical, medicolegal, and ethical considerations for early surgical termination, can maintain trust within the healthcare team, appropriately refer patients to specialist colleagues when necessary, and enhance patient outcomes and team performance. 

Preoperative termination may be required due to patient factors, ethical considerations, or procedural challenges. Patients who present on the day of surgery with acute medical conditions, such as myocardial infarction, stroke, hypertensive emergencies, active infections, or unstable chronic illnesses like renal failure, are unsuitable for surgery. These conditions must be addressed and stabilized before MMS can proceed. Additionally, anticoagulation issues, such as an international normalized ratio (INR) greater than 3.5, may necessitate a delay to reduce bleeding risks, though such cases are not absolute contraindications. Ethical considerations also play a vital role. Patients who lack decision-making capacity and do not have a surrogate decision-maker present cannot provide consent, which is essential for proceeding with MMS. Legal documentation, such as advanced directives or durable medical power of attorney, should be in place to address these scenarios. Furthermore, neurologic or psychiatric conditions, such as dementia or acute psychosis, may make it challenging for patients to tolerate the extended duration of MMS. Procedural issues, such as the inability to verify the correct surgical site or findings of benign lesions upon biopsy review, may also necessitate rescheduling to avoid unnecessary or inappropriate surgery.

Intraoperative termination of MMS can occur due to various reasons, including unresectable disease, reduced patient comfort, patient decompensation, severe complications, or injury to surgical staff. Tumors that invade deeper structures, such as bone, orbit, or mucosal sites, may exceed the scope of MMS under local anesthesia, requiring referral to specialists for surgery under general anesthesia. Similarly, inadequate anesthesia or patient discomfort due to prolonged procedures may necessitate stopping surgery. Surgeons should plan for such scenarios by using alternative anesthetic techniques, such as regional blocks or longer-acting anesthetics, and by discussing these options with patients preoperatively. Sudden patient decompensation, such as cardiac arrest, stroke, or respiratory failure, is another critical reason to terminate MMS and redirect the patient to emergency care. Severe intraoperative complications, like retrobulbar hemorrhage or signs of anesthetic toxicity, require immediate intervention and possible referral to specialists. Finally, injuries to the Mohs surgeon or staff, such as needlestick injuries or laser-related accidents, may also lead to surgical delays to ensure the safety and health of the surgical team.

Healthcare teams play a critical role in managing these challenges effectively. Physicians and surgeons lead patient evaluations, make critical decisions about termination or continuation, and coordinate referrals when necessary. Advanced practitioners assist in patient assessments and intraoperative care, ensuring patient comfort and procedural efficiency. Nurses monitor patient vitals and support the surgical team during procedures. Pathologists collaborate with surgeons to confirm diagnoses and provide critical information for surgical planning. 

By fostering a culture of collaboration and communication, healthcare teams can enhance the quality of patient care during MMS. Preoperative planning, ethical decision-making, and robust risk management protocols are essential to addressing the challenges of MMS termination. Clear patient education about risks and procedural details builds trust and reduces the likelihood of mid-procedure withdrawal. Intraoperative challenges require vigilance and adaptability from all team members to ensure optimal patient safety and procedural outcomes. Through these efforts, healthcare teams can uphold the high standards of care associated with MMS and maintain trust in their ability to provide safe, effective treatment even in complex situations.