Paramedian forehead flap in the treatment of nasal, non-melanoma skin cancer: a cross-sectional study

ABSTRACT Introduction: nose is the central point of the face and vulnerable to the occurence of non-melanoma skin cancer (NMSC), impacting on appearance. The paramedian forehead flap (PMFF) is considered the best option to treat extensive nasal defects. The objective of this study is to present the experience on PMFF for nasal reconstruction in the treatment of NMSC of a cancer referral center. Methods: retrospective study was carried out through data from medical records of patients who underwent nasal reconstruction with PMFF due to NMSC at the Cancer Institute of the State of São Paulo (ICESP). Results: 111 patients were identified, mostly ederly, with comorbidities and on initial tumors (T1 and T2). Basal cell carcinoma (BCC) was the predominant histological type. Dorsum and tip were the most affected subunitis. In addition to skin coverage, reconstruction of the lining and structural framework was also performed in half of the cases. Second intention healing was the technique of choice in closing the donor area. Pedicle division ocurred predominantly in the second operation and the median time to complete reconstruction was 6 months. There were low complication rates. Conclusions: the PMFF is safe and effective to treat nose NMSC, even in cases of high complexity. Since the treatment time can be prolonged and impact on quality of life, it is essential to emphasize and discuss this aspect with the patients before surgery.


INTRODUCTION
T he nose is the most central and prominent point on the human face.Its size, shape, and symmetry are fundamental in defining an attractive face 1 .
Due to its prominent location and the delicacy of the skin that covers it, the nose is also particularly vulnerable to injuries of different natures.Trauma, infections, and neoplasms can disfigure it, compromising its function and appearance, with serious consequences for quality of life 2 .
Historically, the treatment of nasal deformities has been described and studied through victims of war wounds and infectious diseases 1 .In the contemporary world, however, non-melanoma skin cancer (NMSC) is highlighted as a cause of nose mutilation.NMSC was diagnosed in more than 1 million people worldwide in 2018 3 .In the United States, where this type of cancer is the most frequent, there are estimates of mortality of 4,500 people per year and an annual cost of US$ 8.1 billion to the health system [4][5][6] .In Brazil, 177,000 new cases and 2,000 deaths are estimated in 2020 7 .
The paramedian forehead flap (PMFF) is considered the best option for the treatment of extensive defects in the nose, providing similar skin and reliable vascularization 8,9 .However, factors such as age, comorbidities, and oncological status can negatively impact surgical outcomes.Due to the importance that NMSC is currently gaining as a cause of complex nasal defects that require reconstruction, it is important to know the clinical and surgical aspects that determine the success of treatment with this type of flap.
The aim of this study is to present the experience of a reference oncology center in the use of PMFF for nose reconstructions in the treatment of NMSC.This case series aims to reinforce the role of this technique in the management of complex nasal defects, demonstrating its safety and alerting to the pitfalls that can negatively impact results.

METHODS
We conducted a retrospective study by collecting data from the medical records of patients who underwent nasal reconstruction with PMFF due to NMSC at the Cancer Institute of the State of São Paulo (ICESP) between January 1, 2011, and December 31, 2019.
We excluded patients with incomplete data in medical records.
We collected data on epidemiological profile, comorbidities, histological type of skin cancer, staging, and follow-up time.We also gathered surgery-related information, such as affected subunits, nasal lining reconstruction or structural framework, interval until pedicle release, complications, total number of surgeries per patient, type of anesthesia, and time to completion of the reconstruction.
We obtained preoperative, intraoperative, and postoperative photographic records, as well as informed consent forms to perform the images.Photographic analysis allowed the identification of the number of nasal subunits affected by the neoplasm, as well as the other facial units involved by the same lesion, in addition to calculating the resected area.All photographic analyzes were performed using the Adobe ® Photoshop software.
We described data according to nature and distribution.Thus, we described nonparametric variables by percentage and interquartile range (IQR),

RESULTS
We identified 111 patients surgically treated for nasal NMSC and reconstructed with PMFF in the ICESP database between January 1, 2011, and December 31, 2019 (62 males and 49 females).
Regarding education, most patients had complete elementary school (64.9%), followed by complete high school (21.6%); 9.4% had not attended school.
The soft triangle (28.8%) and the columella (15.3%) were less affected (Figure 1).In lesions that involved only lateral subunits, the use of PMFF ipsilateral to the defect was the preference in this series (67.3%).In addition to the nose, other facial units were affected by the same neoplasm in 28 patients (25.2%).
Middle third (60.7%) and orbitopalpebral region Ribeiro Paramedian forehead flap in the treatment of nasal, non-melanoma skin cancer: a cross-sectional study (39.3%) were the most common.Lip involvement was identified in seven patients (25%) and one patient had facial nerve involvement.Almost half (42.8%) of the patients who had other facial units affected had these regions treated with a second pedicled flap.Another 39.2% were treated using the same forehead flap.
The pedicle was released in the second surgery in 80.2% of the patients and in the third surgery in 14.2%.The median time between performing the flap and releasing the pedicle was 52.5 days (IQR 35-98).About half of the patients (42.3%) completed the reconstruction with only two procedures, while 28.9% needed three.Another 24.3% needed additional surgical procedures.The median time to completion of the reconstruction was six months (IQR 3-24).

DISCUSSION
The projection of the nose in a plane anterior to the rest of the face makes this structure vulnerable to ultraviolet exposure, an important carcinogenic factor.Therefore, it is the place most affected by NMSC 10 .Similar to other large published series, individuals with nose NMSC in our series were predominantly men, elderly, and fair-skinned 11,12 .Cardiovascular diseases were the main comorbidities found, prevalent in a population with such characteristics.In agreement with the literature, the main histological type in this study was basal cell carcinoma (BCC), followed by squamous cell carcinoma (SCC) 11 .
Through a review of 420 patients, Sanniec et al. observed that the nasal subunits most involved by the neoplasm were the tip and wings 13 .In our sample, however, dorsum (48.6%) and tip (46.8%) were the most prevalent sites.The less affected subunits coincided, though, represented by the soft triangle (28.8% vs. 29%) and columella (15.3% vs. 10%).
It is likely that these discrepancies are explained by differences in photoexposure, as the subunits located inferior to the nasal tip angle are relatively protected from the sun.
The main treatment modality for this neoplasm is surgical resection 14,15 , capable of causing extensive failure of nasal coverage, structure, and lining.The defect reconstruction may require tissue transfer, with the aim of repairing these three layers.
The paramedian forehead flap is considered the best option for the treatment of these defects, especially when extensive, as it provides adequate coverage, reliable vascularization (based on the supratrochlear artery), and skin with characteristics similar to that of the nose 8,9 .Lesions in lateral subunits can be repaired using the pedicle ipsilateral or contralateral to the defect.In this study, there was a preference for the use of the ipsilateral base flap (67.3%).This option shortens the distance between the donor and recipient areas, allowing the creation of a smaller flap 16,17 .On the other hand, the contralateral base flap minimizes pedicle distortion and is related to lower long-term scar retraction 18 .
The local staging of NMSC is directly related to the size of the tumor 19 .Most of the population in this study was diagnosed with T1 and T2 tumors (36% and 35.1%, respectively), with a mean area of 7.98 cm² compromised by the neoplasm.Due to the exposed location, skin lesions in the nose are often identified by the patients themselves, with early diagnosis in the course of the disease 10 .When there is an extension of the neoplasm to other face parts, commonly the middle third, orbitopalpebral region, and lip, reconstruction becomes more challenging.For these cases, Menick proposed the use of a second or third flap, using different reconstructions for each unit 8 .In this study, the PMFF was used as a single reconstruction for all affected units in 39.2%.The breach of Menick's principle is justified by the characteristics of this population, represented mostly by elderly individuals with multiple comorbidities, who benefit from less aggressive procedures.
T3 (20.7%) and T4 (6.3%) locally advanced tumors represented a considerable portion of this sample.In these cases, there is a greater chance of involvement of the nose deep structures 19 , which require joint reconstruction with skin coverage.If absent, the structural framework of the nose, formed by its osteofibrocartilaginous skeleton, must be redone.
The objective is to shape and support the inner and outer layers of the nose, in addition to protecting the entire structure against scar retraction 12 .The repair of the nasal mucosa, which makes up the inner lining, must also be performed for adequate airway flow 13 .In this series, almost half of the patients required lining reconstruction (44.1%), generally with another flap.
This number exceeds that of patients with T3 and T4 tumors.The explanation lies in the need for threedimensional margins at the time of resection, which may include the deepest layers even in early tumors.On the other hand, scaffold reconstruction was necessary in 34.2%, using mostly autologous cartilaginous grafts from the ear and septum.
Traditionally, PMFF is performed in two steps.
In the first, tissue transfer is carried out to close the defect, keeping the pedicle still connected to the donor area.After 20 days, when the vascularization of the flap becomes independent of the supratrochlear artery, its base is sectioned [20][21][22][23] .The longer interval between the creation of the flap and the release of the pedicle observed in our series can be attributed to several factors.Due to the complexity of the cases operated on in our service, there was a greater need for intermediate procedures before pedicle section, with an average of 3.12 surgeries per patient.There is also the logistical factor related to the great surgical demand of a public service of reference in oncological reconstructions.

R E S U M O R E S U M O
and parametric ones, by mean and standard deviation.Nominal or dichotomous variables were presented by percentage of frequency.We performed the tests of Spearman Rank correlation coefficient between the variables affected subunits, lining or structural framework reconstruction, surgical time for pedicle release, complications, total number of surgeries per patient, and time to completion of the reconstruction.The Ethics Committee for the Analysis of Research Projects of ICESP approved this study, following the Declaration of Helsinki and the Document of the Americas, under registration 1666/20.

Figure 2 .
Figure 2. A 51-year-old woman with a history of smoking, without other comorbidities.She presented with a basal cell carcinoma involving mainly the nasal dorsum, but also part of the lateral walls and tip (A/B).The lesion was resected (C) and reconstructed with a paramedian forehead flap (D).Two flap weight reductions were performed.The pedicle was released after 66 days (E/F).

Table 2 -
Surgical characteristics related to reconstruction.