Clinical Outcomes and Complications in Complex Closures Under Local Anaesthesia Post-Mohs Surgery

Abstract

Background:

Mohs micrographic surgery offers high cure rates of cutaneous malignancies, but surgeons are often faced with large and complicated defects after tumour removal.

Objectives:

To assess the safety and complication rates of large flaps and grafts (measuring ≥30 cm²) and larger complex linear closures (CLC, ≥12.5 cm, as defined by the American Medical Association Current Procedural Terminology code set), when performed under local anaesthesia.

Methods:

A retrospective analysis was conducted on a cohort of patients who underwent skin cancer treatment by Mohs at an academic institution (UCSD) from January 1, 2010, to December 31, 2022, and whose defects were repaired with CLC, flap, or skin graft. Demographic, surgical, and complication data were collected and analyzed.

Results:

Of the 436 patients who met inclusion criteria, 39 underwent CLC, 344 underwent flap reconstruction, and 53 underwent grafting. Adverse effects to local anaesthesia were notably absent in all treatment methods. Overall complication rate was noted to be 16.1% (70/436). Complications varied across treatment methods, encompassing infection (6.0%, 26/436), bleeding (3.2%, 14/436), hematoma (5.0%, 22/436), seroma (0.2%, 1/436), and flap/graft necrosis (6.5%, 26/397).

Conclusions:

Our data suggest that large CLC, flaps, and grafts can be safely performed under local anaesthesia, but have higher complication rates compared to smaller reconstructions.

Introduction

Mohs micrographic surgery (MMS) offers high cure rates of cutaneous malignancies with the added advantage of maximal tissue preservation. However, Mohs surgeons are often faced with large and complicated defects after tumour removal. Depending on the size and location, surgical defects may require large complex closures, flaps, grafts, and/or multi-stage procedures to obtain optimal results. ¹ The number and scope of surgical procedures performed under local anaesthesia has grown rapidly, with an increase from 400,000 surgeries in 1984 to 8.3 million in 2000. ² With this transition, the safety of performing large cutaneous reconstructions in an ambulatory setting, under local anaesthesia, is worth evaluating.

Several retrospective studies and case series have demonstrated the safety of various flaps and grafts under local anaesthesia.^3-5 Few studies, however, have assessed the safety of larger flaps and grafts (measuring at least 30 cm²) and/or larger linear repairs (12.5 cm or longer) under local anaesthesia.^6,7 As local anaesthesia offers several benefits over general anaesthesia, including reduced risk of complications in patients with cardiac and pulmonary comorbidities, lower cost, and decreased incidence of nausea, vomiting, and hypotension, evaluating the safety of performing large flaps and grafts under local anaesthesia is of significant interest. ⁸

Methods

Data Collection

The study was performed through a retrospective chart review of adult patients in the UCSD Epic Electronic Medical Record system who presented at the UCSD Dermatologic and Mohs Micrographic Surgery Center from January 1, 2010, to December 31, 2022. Mohs surgery patients who underwent dermatologic surgery with complex linear closures (CLS; 12.5 cm or longer), cutaneous adjacent tissue transfers (flaps >30 cm²), or skin grafts (>30 cm²) were identified. Health records were reviewed to extract patient characteristics and treatment outcomes. Complications including adverse reaction to anaesthetic, emergency medical intervention for any reason, ER visit, admission to hospital because of a surgical complication, death, hyperpigmentation, bleeding, hematoma, infection, dehiscence, partial flap necrosis, total flap necrosis, irritant, or allergic contact dermatitis were noted. Cases with additional postoperative interventions including treatment with pulsed dye laser, intralesional triamcinolone and/or 5-fluorouracil, dermabrasion, and laser hair removal were noted as well. The institutional review board approved this study.

Statistical Analysis

Statistical analysis was performed using GraphPad Prism (GraphPad Inc., USA). Continuous data were summarized descriptively by mean, standard deviation, and range. Categorical data were presented as enumerations and percentages. Correlation testing as well as univariate and/or multivariate regression analyses were performed to determine the effect measures of variables on our outcomes of interest. Data were analyzed using analysis of variance (ANOVA). P-values ≤.05 were deemed statistically significant.

Results

Supplemental Table S1 summarizes the data obtained from this study. Of the 436 patients who met inclusion criteria, 39 underwent CLC, 344 underwent flap reconstruction, and 53 underwent grafting. Adverse effects to local anaesthesia were notably absent in all treatment methods. The mean age of patients undergoing grafts, flaps, and CLC were 76.7, 69.8, and 65.9 years, respectively (P < .0001). There was no statistically significant difference in the type or the location of tumour, comorbidities including history of immunosuppression or radiation, use of anticoagulation, diabetes, or use of prophylactic antibiotics noted across the groups. Postoperative size of defect (prior to reconstruction) was largest for those repaired using grafts (6.47 cm), followed by CLC (5.93 cm) and flaps (4.17 cm; P < .0001 CLC vs flap and flap vs graft). Total complication rates (including partial/total flap/graft necrosis) were 17.9% (7/39), 12.8% (44/344), and 35.8% (19/53) for repairs using CLC, flaps, and grafts, respectively. There was no statistically significant difference in the rates of surgical complications including infection, dehiscence, and hematoma noted across the various groups. A minority of patients needed additional interventions after flap reconstruction; 3 patients (0.9%) required intralesional steroids, and 1 patient each (0.3%) required 5-fluorouracil and dermabrasion. Patients in our cohort did not require post-surgical interventions after CLC or grafts.

On average, patients were followed by dermatologists for an extended period (CLC 38.1 months, flaps 36.6 months, and grafts 29.8 months).

Discussion

Our data captured patients over a 12-year period, with the majority undergoing MMS for non-melanoma skin cancers. We did not identify any adverse effects to local anaesthetics including nausea, neurological symptoms, or other symptoms requiring emergency medical interventions. ⁹ Surgical procedures varied, with graft procedures often performed on older patients with a higher prevalence of diabetes and malignancies on the scalp. In contrast, flap closures were commonly performed for facial and scalp malignancies and were associated with larger surgical lengths.

Infections were more frequently observed in patients who had their defects repaired using skin grafts, particularly during the second week post-surgery. Out of the 4 patients who underwent repair with CLC and experienced infected surgical sites, one had HIV infection, and another was diabetic. Among the 9 patients who received graft repairs and developed infections, 3 were diabetic, and 2 of these were also on immunosuppressive medications (cyclosporine and prednisone). For those undergoing flap reconstructions, 13 patients experienced infected surgical sites, 3 of whom were immunocompromised due to a history of transplantation or ongoing treatment for other malignancies.

Within our cohort, a notable observation was that the majority of patients who developed hematomas were not anticoagulated at the time of their procedures. Notably, the solitary patient who developed a hematoma post CLC was not under anticoagulation. Among the 5 patients who developed hematoma following graft procedures, merely one was on anticoagulation therapy, specifically with aspirin at a dosage of 325 mg, during the surgical intervention. In the subgroup of 16 patients who developed hematomas after flap reconstructions, distinct anticoagulation regimens were identified: 2 individuals were on apixaban, while 1 patient each was on rivaroxaban, enoxaparin, and warfarin.

Further analyzing patients who underwent flap reconstruction and encountered any form of bleeding (2.6%, 9/344), the preponderance was actively on anticoagulation. Specifically, among 9 patients, 4 were on warfarin (44.4%, 4/9), 1 patient was on clopidogrel (11.1%, 1/9), and 5 patients were using aspirin (55.5%, 5/9). Of these patients, 3 were on warfarin and aspirin, and 1 patient was on clopidogrel and aspirin. Interestingly, only 3 patients who were not on any anticoagulation regimen experienced any type of bleeding, constituting 0.9% (3/344) of the cohort.

Regarding patients who underwent repairs with grafts and subsequently faced bleeding incidents, 5.7% (3/53) experienced such events. Within this subset, one patient was taking both clopidogrel and aspirin, while another patient was on warfarin. Similarly, among the 2 patients who underwent repairs using CLC and encountered bleeding (5.1%, 2/39), 1 individual was concurrently utilizing aspirin.

Among the cohort, there were instances of flap dehiscence observed in 11 patients (3.2%, 11/344). Out of these, 4 cases (1.2%, 4/344) were accompanied by infected surgical sites, while 1 case (0.3%, 1/344) involved bleeding. In terms of partial flap necrosis, there was one case out of the total observed (0.3%, 1/344) that was also affected by infection.

In the context of graft-related complications, the lone case of donor site dehiscence was due to hematoma formation (1.9%, 1/53). Additionally, among the 8 cases of partial graft necrosis (15.1%, 8/53), 4 instances (7.5%, 4/53) were linked to infections, and 2 cases (3.8%, 2/53) involved the development of hematomas. Remarkably, a parallel pattern emerged among the 8 patients who experienced total graft necrosis (15.1%, 8/53), where 4 cases (7.5%, 4/53) were impacted by infection and 2 cases (3.8%, 2/53) demonstrated concurrent hematoma formation.

In a study comparing outcomes of 96 forehead flaps, 35 of which (36.5%) were done in an office-based procedure room using local anaesthesia only, there were 13 total postoperative complications (13.5%), but there was no statistically significant difference in complication rate between groups (office-based: 3 complications, 8.6%; operating room: 10 complications, 16.4%). ⁴ Rates of infection requiring antibiotic therapy were slightly higher when procedures were performed in the office-based setting versus operating room: 3 patients (8.6%) versus 2 patients (3.3%). In comparison, our overall complication rate in this study is 16.1% (n = 70). ⁴

Prior studies have also demonstrated that complex surgeries under local anaesthesia are both feasible and safe with good patient-reported outcomes. ³ Another study of 639 patients undergoing flap reconstruction noted no major complications. Problems related to bleeding were the most prevalent; active bleeding requiring physician intervention was seen in 8.4% and hematoma formation in 0.4% of flaps. ¹ A total of 2.6% of our patients undergoing large flap reconstructions experienced bleeding and 4.7% experienced hematomas. The study reported postoperative infections were seen in 1.7% of patients after the initial surgery and 3.4% after division of the pedicle. In contrast, 3.8% of our patients undergoing repair using flaps required treatment for infections. Dehiscence was noted in 3.2% of the patients undergoing flap reconstruction at our institution while the study reported primary or secondary dehiscence in 0.5% of their patients. ¹ Finally, partial full-thickness flap necrosis was seen in 2.3% and total flap necrosis in 0.6% of patients in that study. In comparison, 2.6% and 0.3% of our patients were noted to have partial and total flap necrosis, respectively. This is in line with other reports; a study of 68 patients undergoing large scalp flap repairs (12-115 cm²) under local anaesthetics noted 2.9% of patients had flap necrosis and a similar number had dehiscence. ⁷

Of note, patients are routinely prescribed prophylactic antibiotics post large reconstructions, for example, large full-thickness grafts greater than 30 cm², meaning that the presenting tumours were often neglected to larger size (patients with poor self-care) and/or aggressive tumours with rapid growth in immunosuppressed patients, at our practice which may be a confounding factor and limits direct comparison with any prior studies on this topic. In our cohort, infection rates were higher than expected, possibly due to factors such as larger reconstructions, comorbidities, and immunocompromised states. These findings suggest that infection risk might be higher in certain patient populations, and future studies are warranted to explore the contributing factors in more detail.

Collectively, our study contributes valuable insights into the complication rates and risk factors associated with different repair techniques after MMS, further informing clinical decision-making and patient care. Though these results are based on a relatively large sample size, the procedures were performed over a large time frame, and treatments were performed by multiple surgeons. Thus, treatment approaches may have varied, and these results may not be generalizable to all patients undergoing large reconstructions. Future research could incorporate larger sample sizes and incorporate a more comprehensive evaluation of treatment outcomes including cosmetic outcomes and quality of life. Future studies could further aim to better understand the epidemiology and risk factors of patients undergoing large CLC, flaps, and grafts.

We conclude that large CLC, flaps, and grafts can be safely performed by Mohs surgeons using local anaesthetics, but larger reconstructions may carry greater risk of surgical complications. The study also highlighted the comorbidities, risk factors, and skin cancer characteristics of these patients, which can assist dermatologic surgeons in making treatment decisions.

Supplemental Material

sj-docx-1-cms-10.1177_12034754251316297 – Supplemental material for Clinical Outcomes and Complications in Complex Closures Under Local Anaesthesia Post-Mohs Surgery

Supplemental material, sj-docx-1-cms-10.1177_12034754251316297 for Clinical Outcomes and Complications in Complex Closures Under Local Anaesthesia Post-Mohs Surgery by Somaira Nowsheen, Vy X. Pham, Shaundra Eichstadt and Shang I Brian Jiang in Journal of Cutaneous Medicine and Surgery