Surgical Outcomes Following Mohs Micrographic Surgery for Basal Cell Carcinoma on the Distal Third of the Nose

J Clin Aesthet Dermatol. 2022;15(6):32-36.

by Lisa Faye Fronek, DO, and David Dorton, DO, FAOCD

Both authors are with the Department of Dermatology, HCA Healthcare/USF Morsani College of Medicine at Largo Medical Center Program in Largo, Florida.

FUNDING: No funding was provided for this article.

DISCLOSURES: The authors report no conflicts of interest relevant to the content of this article.

ABSTRACT: Objective. The primary aim of this study is to determine a quantifiable difference in surgical outcomes between local skin flap, full thickness skin graft (FTSG), and secondary intention (SI) following Mohs micrographic surgery (MMS) for basal cell carcinoma (BCC) on the distal third of the nose.

Methods. A retrospective chart review of 66 MMS defects on the distal third of the nose performed by a single surgeon between June 2019 to June 2020 was completed. Clinical images of MMS defects and postoperative scars at six months were recorded and measured by the Vancouver Scar Scale (VSS). Pearson Chi-square and Fisher’s Exact tests were utilized to determine the relationship between the main predictor variables and VSS.

Results. Of the 66 patients retained, 52 were deemed to have low VSS (77.61%), 11 had medium VSS (16.42%) and three had high VSS (4.48%). Of the 52 patients with low VSS, 40 underwent local flap (76.92%), nine underwent FTSG (17.31%), and three healed by SI (5.77%). Of the 11 patients with medium VSS, two underwent local flap (18.15%), nine underwent FTSG (81.82%), and zero healed by SI. Of the three patients with high VSS, zero underwent local flap or SI, while all three underwent FTSG (100%). Bivariate analysis demonstrated that repair type employed was associated with VSS at six months (p<0.0001) with patients treated with local skin flap having better outcomes.

Conclusion. Our data illustrate that local skin flaps might result in a lower VSS at six months compared to FTSG or SI, therefore offering superior surgical outcomes in the treatment of BCC on the distal third of the nose.

Keywords: Mohs micrographic surgery, local skin flap, full thickness skin graft, secondary intention

Mohs micrographic surgery (MMS) is the preferred treatment for basal cell carcinoma (BCC) on cosmetically sensitive areas such as the nose. It provides the highest tumor cure rates through complete margin control and allows for maximal tissue conservation.^1,2 Once the tumor has been completely excised, the Mohs surgeon must choose the surgical reconstruction that will result in the best surgical and cosmetic outcome for the patient.³ Repair of nasal structures is particularly challenging due to the unique anatomy of the area, varying degrees of convexity and concavity in close proximity, and the relative paucity of redundant skin to utilize. 

Many surgeons divide nasal defects into two categories: those on the upper two thirds of the nose and those on the lower third of the nose.⁴ While a primary closure is often seen as the simplest reconstruction, this is significantly more challenging and often impossible on tissue-limited areas such as the supratip, infratip, and alae of the nose.⁵ Due to the lack of laxity of the cartilaginous distal third of the nose, many surgeons will opt for a local skin flap, full thickness skin graft (FTSG), or leave the defect to heal by secondary intention (SI).⁴ Each surgeon has his or her preference; however, there is no algorithmic process to assist in the decision. In the study presented here, we compare surgical outcomes of local skin flap, FTSG, and SI using an objective scar measurement following MMS on the distal third of the nose. 

Objective 

The goal of this study is to identify if there is a measurable difference in surgical outcomes, as determined by the Vancouver Scar Scale (VSS), between closures using a local skin flap, FTSG, or SI following MMS for BCC on the distal third of the nose.

Methods

A retrospective chart review was completed via electronic medical record review of MMS defects for BCC on the distal third of the nose performed by a single surgeon at Bay Dermatology and Cosmetic Surgery from June 2019 to June 2020. Cases were included in the analysis if the patient was older than 18 years of age and had a biopsy-proven BCC on the supratip, infratip, or nasal alae. Patients were excluded if they had a prior history of non-melanoma skin cancer on any aspect of the nose or were on systemic chemotherapy or systemic immunosuppressive medications. Seventy-seven patients met inclusion criteria; 11 patients were lost to follow up. This research activity was determined to be exempt from Institutional Review Board oversight in accordance with current regulations and institutional policy. Surgical and postoperative records were reviewed and compiled, including patient demographics (age, sex, ethnicity), BCC histological subtype, tumor location, pre-operative size, defect size prior to repair, depth of final defect, number of stages required to clear tumor, type of repair, and sebaceous quality of the nose. 

Clinical images of MMS defects and postoperative scars at one week and six months (Figure 1) were reviewed and scored by two physicians (LF and DD) using the VSS (Table 1). The VSS is a standardized grading instrument used to objectively measure a surgical scar and is comprised of four parameters: pigmentation, vascularity, pliability, and height.⁶ While this can be utilized as a continuous variable, we chose to stratify the scores into three groups in order to assist in the differentiation between optimal scar healing, moderate scar healing, and poor scar healing.^6,7 Based on this score, patients fell into three categories: low (0–3), medium (4–6), and high (7–13). These numerical groupings were based on how many parameters of the VSS contributed to the overall score; therefore, a lower score indicates a more satisfactory surgical outcome and a less evident scar. We performed Pearson Chi-square and Fisher’s Exact tests to examine the association between the main predictor variables and VSS. All statistical analyses were performed using the SPSS v26.0 statistical software. 

Results

Patient demographics. Of the 77 patients accepted to this study, 38 were male and 39 were female. Eleven patients were lost to follow up. The average age was 70 years (standard deviation 10.7). Patients were predominantly White (95%), followed by Hispanic (5%). Patient demographics are recorded in Table 2.

Oncologic characteristics. The most frequent BCC histologic subtype was nodular (48.05%), followed by infiltrative (23.38%), mixed subtype (16.88%), and superficial (11.69%). Skin malignancies were located on the infratip (22.7%), nasal ala (51.5%), and supratip (25.8%). 

Surgical outcomes. The most frequent repair was a local skin flap (62.34%), followed by FTSG (33.77%), and SI (3.90%). Wound characteristics and outcomes are summarized in Table 3. There were no instances of excessive postoperative bleeding, hematoma, surgical site infection, or other complications, and no scar revisions were performed after any of the procedures.

Of the 66 patients retained, 52 were deemed to have low VSS (77.61%), 11 had medium VSS (16.42%) and three had high VSS (4.48%). Of the 52 patients with low VSS, 40 underwent local flap (76.92%), nine underwent FTSG (17.31%), and three healed by SI (5.77%). Of the 11 patients with medium VSS, two underwent local flap (18.15%), nine underwent FTSG (81.82%), and zero healed by SI. Of the three patients with high VSS, zero underwent local flap or SI, while all three underwent FTSG (100%). 

Bivariate analysis demonstrated that repair type employed was significantly associated with VSS at six months (p<0.0001) with patients treated with local skin flap having better outcomes. Therefore, the data suggest an association between the use of a local skin flap on the distal third of the nose and a low VSS at 6 months. Notably, age (p=0.59), sex (p=0.08), ethnicity (p=0.52), location of BCC (p =0.98), histologic subtype (p=0.82), depth of final defect (p=0.60), number of stages required to clear tumor (p=0.18), preoperative size (p=0.6), defect size prior to repair (p=0.9) and sebaceous quality of the skin (p=0.13) were not associated with a difference in VSS at six-months post-operative.

Discussion 

BCC is the most common cutaneous malignancy and occurs predominantly in White patients on sun-exposed areas, such as the face.⁸ This study reflected current epidemiologic patterns of histological subtypes of BCC, where nodular is the most common subtype (48% in present study).^8,9 The second most common subtype in our cohort was infiltrative (23.38%). While infiltrative BCC patterns may occasionally result in deeper final defects, there was no statistical significance between defect depth and VSS (p=0.06, Table 3) found above. Up to 40 percent of BCCs may demonstrate more than one histological subtype;⁸ in our study, 16.88 percent of the patients had mixed histology of BCC. Lastly, 11.69 percent of our study cohort demonstrated a superficial pattern. 

Complete surgical excision is the standard of care to treat BCC, and MMS is often employed due to its tissue sparing approach resulting in smaller final defect sizes, high clinical and histological cure rates, and decreased tumor recurrence.^8-10 After surgical clearance of the tumor, the surgeon must decide how to close the surgical defect utilizing either a linear repair, local skin flap, skin graft (either split thickness or FTSG), or leaving the wound to heal by SI.^3,9 This decision is based upon the anatomical location, defect size, defect depth, and likelihood of recurrence. The surgeon must also bear in mind certain patient characteristics such as age, health, function and cosmetic concerns. Comorbidities to consider include diabetes, cardiovascular disease, and cigarette smoking.^3,9 

Repair on nasal structures is particularly challenging due to the unique anatomy, varying degrees of convexity and concavity in close proximity, and relative paucity of redundant skin from the periphery to utilize.¹¹ Additionally, the discrete cosmetic subunits of the face must be taken into account in order to accurately match color, texture, sebaceous quality, and depth of the subunits involved.¹¹ Finally, the surgeon must also be mindful of how nasal structures assist in facial function, expression, and coverage over the bony, cartilaginous and mucosal infrastructure.² This study focused specifically on surgical repairs following MMS for BCC on the distal third of the nose. The locations considered were the nasal alae, supratip, and infratip. The purpose was to assess if there were differences in the surgical outcome, as measured by the VSS, based on the type of repair employed; we aimed to specifically contrast local skin flaps, FTSG and SI healing. 

Among the 66 patients presented here, 42 (63.6%) underwent a local skin flap, followed by 21 (31.8%) who underwent FTSG, and three (4.6%) who healed by SI. The local skin flaps employed were rotation, advancement, and transposition. Our findings indicate that there is a statistically significant difference in the type of repair type employed and the VSS at 6-months (p<0.05, Table 3). It is notable that among the 42 patients who underwent a local skin flap, 40 (95.24%) recorded low VSS, two (4.76%) resulted in medium VSS, and none rated a high VSS. For the 21 patients who underwent a FTSG, 9 (42.86%) logged a low VSS, 9 (42.86%) resulted in medium VSS, and 3 (14.28%) were graded with high VSS. 

These data support current research indicating local skin flaps provide better surgical and cosmetic outcomes compared to FTSG.^9,10,12 In a study investigating patient satisfaction of 86 patients after MMS, Lee et al⁹ found that patients were more satisfied following local skin flaps versus FTSG. Jacobs et al¹² found that the mean Visual Analogue Score (where 0 is the worse score and 100 is the best possible score) was higher for flaps compared to grafts on more complex locations such as the nasal tip and nasal alae, which is in accordance with our study. The key benefit of a local flap is the ability to more effectively match color, texture and thickness, commonly using tissue reservoir from the same cosmetic subunit to close the surgical defect.^9-11,13 In contrast, FTSGs rely on tissue that is less likely to match in texture, color, and sebaceous quality.

In addition, local skin flaps, specifically ones that are random pattern flaps, depend on a vascular plexus for blood supply. Their minimally perturbed vascular supply is likely what contributed to a decreased VSS at the six-month mark for local skin flaps. In contrast, FTSGs employ a tissue reservoir that has been cut off from its blood supply; this requires that the graft re-establish capillary connections surrounding the surgical defect and frequently results in vascular changes, dyspigmentation, or contour irregularities.^9,12 Any of these tissue mismatches can lead to higher scores as graded by the VSS, resulting in poorer surgical outcomes. 

All three of the patients who healed by SI were found to have low VSS (100%); none had medium or high VSS (Table 3). After investigating the patient considerations of these three patients who healed by SI, two of the defects were on the alar crease and one was on the supratip. This mirrors current surgical recommendations that allow for SI on concave locations, such as the alar crease.³ It is also worth noting that all three patients had defects of only the dermis and subcutaneous tissue; none of these were full thickness defects. This echoes the notion that SI is only recommended for superficial defects of the distal third of the nose; full thickness surgical defects are most appropriately managed with a surgical closure.⁴ While our study did not find any significance in the degree of sebaceous quality of the nose, Stigall et al⁴ describe that in patients with highly sebaceous skin, SI might lead to more favorable outcomes compared to a surgical repair. 

While low VSS was achieved in patients who underwent SI (Table 3), it is also necessary to mention the minimal sample size in this cohort. Similarly small numbers of patients who underwent SI have been reported in other studies.^9-10,13-14 Wollina et al¹⁴ examined 321 patients with BCC on the nose where 178 underwent local skin flaps, 36 underwent FTSG, and only three underwent SI. This might reflect the common preference to avoid SI on convex structures, such as the distal third of the nose, due to the underlying cartilaginous structures. It is also possible that SI results in low VSS due to a lack of the inflammatory response that follows a more intensive surgical repair and the requirement of sutures.³ Considering the low sample size of patients who underwent SI, a higher volume study would be needed to replicate our findings before making firm recommendations on this repair type. Our data does suggest that, in the appropriate setting and with correct patient selection, management by SI may allow for satisfactory healing, as demonstrated by a low VSS.

Limitations. There are a few limitations to our study, the first of which is its small sample size. As previously mentioned, the three patients who underwent SI might underrepresent the importance of this repair option in actual practice. Another limitation might be the surgeon’s definition of distal one third of the nose, as some include the lower aspect of the nasal dorsum in this definition. We included only the supratip, infratip, and nasal alae. Additionally, because BCC is primarily seen in White patients, there was a significantly greater number of White patients in the cohort of this study compared to other ethnicities. While this does reflect current epidemiologic data concerning BCC, the recommendations from our study cannot be extended to patients of other ethnicities.

The findings presented above indicate that more data is needed to adequately assess the VSS for SI. Additionally, it would be of interest to determine which aspects of the VSS (vascularity, pigmentation, pliability or height) are most contributory to long term scar formation. One limitation of the VSS is the lack of patient input into overall scoring; it might also be of use to utilize other scar scales including one that is patient dependent, such as the Patient and Observer Scar Assessment Scale.^7,15,16 Finally, other comorbidities to include in future studies include the body mass index, cigarette smoking, diabetes, and cardiovascular disease, in order to further refine the surgeon’s choice of the optimal closure for each patient.

Conclusion

These findings indicate that local skin flaps might result in a lower VSS at six months compared to FTSG or SI, therefore offering superior surgical outcomes in the treatment of BCC on the distal third of the nose. 

Acknowledgments

We would like to acknowledge Allison Marsh, MPH, for her participation in statistical assessment and analysis.

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