Keywords
Perforator flap - Nasolabial fold - Skin neoplasms
INTRODUCTION
Perforator flaps have been used clinically since the last decade of the twentieth
century, when Allen and Treece [[1]] used the deep inferior epigastric artery perforator flap previously described by
Koshima and Soeda [[2]] for breast reconstruction. In 2005, Hofer et al. [[3]] was the first to apply the perforator technique to the reconstruction of perioral
defects, using the facial artery. Since then, a number of studies on the reconstruction
of nasal oncologic defects using facial perforators have been published [[4]
[5]
[6]
[7]
[8]
[9]]. The facial artery perforator-based flap [[10]] was the first perforator flap for the face. It allows one-stage reconstruction
freedom in flap design, while obviating the necessity to adhere to the length-to-width
ratio previously considered necessary to ensure viability [[8]
[11]].
Several anatomic studies have been performed to identify the position and number of
the perforators that branch off from the facial artery [[3]
[12]
[13]]. While previous studies have mostly focused on the main trunk of the facial artery,
in this study we concentrated on the lateral nasal artery (LNA).
The aim of this study was to investigate the perforators of the LNA and their distribution
along the course of the vessel. Moreover, the clinical application of the LNA perforator
flap is described.
This paper can be considered a guide for approaching this anatomic area with confidence,
since preoperative Doppler imaging is not helpful in finding perforators in the LNA.
Anatomy
Before describing the relevant vascular anatomy, it would be prudent to first highlight
some points regarding the anatomy of the facial artery and its branches in the midface.
Significant variability exists in the vascular anatomy of this area. For the purposes
of this article, we have adopted the nomenclature of more recent authors [[14]
[15]], as illustrated in [Fig. 1]. In describing and naming the lateral nasal and superior labial artery of the facial
artery, we have followed the terminology employed by Nakajima et al. [[14]], which was also used by Loukas et al. [[15]] in a comprehensive recent anatomic study of the vascular patterns of this area.
According to the traditional understanding presented in that study, two major branches
arise from the facial artery near the oral commissure: the superior labial artery
and the LNA, with the latter terminating as the angular artery ([Fig. 1]).
Fig. 1 Course of the lateral nasal artery
A fresh cadaveric dissection showing the course of the lateral nasal artery (LNA,
marked in green), from its origin near the facial artery (FA, marked in red) to where
the superior labial artery (SLA, marked in yellow) splits off from it. The LNA gives
off three perforators (P, marked in light blue). The LNA terminates in the angular
artery (AA) marked in blue.
METHODS
Cadaveric study
Sixteen hemifaces in eight fresh cadavers were dissected under magnifying loupes (Design
for Vision 3.5× Expanded Field, Ronkokoma, NY, USA) to study the LNA perforators.
The LNA was dissected from its origin, where the superior labial artery arises from
the facial artery, up until the superior ala nasi margin, where the superior ala nasi
artery arises from the LNA and the LNA becomes the angular artery ([Fig. 1]).
The LNA was dissected in the caudocranial direction in each case to outline its general
course according to the classification system modified by Nakajima et al. [[14]] ([Fig. 2]).
Fig. 2 Facial artery anatomic patterns
A schematic representation of the three most common distributions of the major branches
of the facial artery. (A) In type A, the facial artery bifurcates into the superior
labial and lateral nasal arteries. (B) In type B, the facial artery divides into the
superior labial and lateral nasal arteries and then terminates as the angular artery.
(C) In type C, the facial artery terminates as the angular artery, but the lateral
nasal artery branches off from the superior labial artery [[14]]. In our anatomic study, type A was the most common, appearing in 10 hemifaces (62.5%).
Type B was found in two hemifaces (12.5%) and type C in four hemifaces (25%).
After the dissection was performed, the total length and diameter of the LNA and its
perforators were measured. The quantity and distribution of the LNA perforators supplying
the overlying skin were then assessed.
Patients
LNA perforator flaps were used to reconstruct 10 nasal and perinasal defects between
January 2012 and December 2013. The mean age of the patients was 79.9 years (range,
70–87 years). The mean follow-up time was 18 months. In all cases, the defects were
secondary after basal cell carcinoma (BCC) excisions.
Surgical technique
After the tumor was excised, reconstruction was planned, adhering as much as possible
to the aesthetic unit principle of nasal reconstruction [[16]]. The reconstructive stage was approached in a freestyle fashion "from the foliage
to the roots," with retrograde dissection of the vessels [[17]]. Given the proximity of the perforators to the main vessel, which can result in
a high percentage of false positives, and considering the constancy of this anatomic
feature, we decided not to use a Doppler probe.
After the first excision on the nasal labial groove up to the subcutaneous tissue,
we performed gentle spreading to show the LNA perforators. The spreading was parallel
to the perforator course without approaching too close to the vessel wall in order
to reduce the risk of spasm.
When performing a propeller flap, we chose the closest perforator vessel to the defect,
whereas we included as many perforators as possible when using a V-Y flap. Once the
perforators were selected, they were gently freed from fibrous attachments to the
levator labii superioris and levator labii superioris alaeque nasi muscles, and the
flap was subsequently islanded on the perforators that were isolated.
The perforator was cuffed with a small portion of the surrounding fatty tissue to
protect the vessel from twisting, stretching, and spasm. We incised the caudal border
of the flap while keeping the cranial border intact if perforator absence or injury
made it necessary to perform a pedicled flap.
Once the perforating artery and vein were identified, the skin was incised circumferentially.
The cutaneous nerves were spared if they did not hinder the movement of the flap.
Dissection of the pedicle was performed until tension-free transposition was achieved
to cover the defect.
RESULTS
Cadaveric study
After determining the general course of the LNA, the measurements described in the
Methods section were analyzed ([Table 1]). The mean total lengths of the LNA and of its perforators were 49.38 mm (range,
40–61 mm) and 16.6 mm (range, 13–23 mm), respectively. The mean diameters of the LNA
and of its perforators were 2.08 mm (range, 1.7–2.5 mm) and 0.91 mm (range, 0.65–1.25
mm).
Table 1
Results of the cadaveric study
|
Hemifaces/(type)
|
Length LNA (cm)
|
Mean length LNA perforators (cm)
|
Diameter LNA (mm)
|
Mean diameter LNA perforators (mm)
|
|
The length and diameter of the lateral nasal artery (LNA) and the mean length and
mean diameter of its perforators in each cadaveric specimen are shown. The letters
in parentheses represent the course of the facial artery according to Nakajima's classification
[[14]], which is presented in [Fig. 2].
|
|
1a (C)
|
5.0
|
1.30
|
2.2
|
0.65
|
|
1b (A)
|
5.2
|
1.45
|
2.2
|
1.00
|
|
2a (A)
|
4.4
|
1.75
|
2.0
|
0.9
|
|
2b (A)
|
4.5
|
1.80
|
2.1
|
0.9
|
|
3a (A)
|
4.5
|
1.45
|
2.0
|
1.10
|
|
3b (C)
|
4.4
|
1.50
|
1.9
|
0.90
|
|
4a (B)
|
4.0
|
1.35
|
2.0
|
0.75
|
|
4b (A)
|
4.5
|
1.75
|
1.8
|
1.15
|
|
5a (A)
|
4.9
|
1.50
|
2.5
|
1.25
|
|
5b (C)
|
4.8
|
1.65
|
1.7
|
0.70
|
|
6a (B)
|
6.0
|
1.75
|
2.5
|
0.90
|
|
6b (A)
|
5.5
|
1.90
|
2.5
|
0.90
|
|
7a (A)
|
4.8
|
1.90
|
1.8
|
0.90
|
|
7b (C)
|
4.6
|
1.55
|
1.9
|
0.85
|
|
8a (A)
|
6.1
|
1.65
|
2.0
|
0.85
|
|
8b (A)
|
5.8
|
2.30
|
2.2
|
0.90
|
The distribution of the perforators over the course of the LNA is presented in [Fig. 3]. The number of perforators varied on each side of the face, so their distribution
in each centimeter of the length of the LNA was assessed. The majority of LNA perforators
originated between 20 and 30 mm along the length of the LNA, corresponding to an area
of approximately 1 cm2 in the upper third of the nasolabial fold lateral to the limit of the ala nasi, before
the LNA gives off the inferior ala nasi artery branch [[14]]. Based on our findings, we mapped the face to indicate areas with a higher probability
of finding perforators ([Fig. 3]).
Fig. 3 Distribution of perforators
The red circle indicates the area with the highest probability of finding perforators.
This area corresponds to the upper third of the nasolabial fold lateral to the limit
of the ala nasi. The bars represent the cumulative number of facial artery perforators
that were found in all cadaveric dissections in consecutive 1-cm sections of the lateral
nasal artery. This landmark is helpful considering the difficulty of performing an
accurate Doppler study of perforators in this area.
Clinical cases
The clinical cases are summarized in [Table 2]. No infection, hematoma, or complete flap necrosis was observed after the procedure.
One patient suffered from venous congestion, but the wound healed well with conservative
treatment during the follow-up period. The cutaneous nerves were maintained in all
of the V-Y flaps because they did not hinder the movement of the flap, whereas they
were spared in two out of the five propeller flaps due to the impossibility of achieving
tension-free transposition.
Table 2
Demographic data regarding the patients and details of the reconstruction procedures
(clinical data)
|
Patients
|
Age (yr)/Sex
|
Pathology
|
Location
|
Defect dimension (cm)
|
Operative methods
|
Complications
|
|
BCC, basal cell carcinoma.
|
|
1
|
81/Female
|
BCC
|
Ala
|
3.1 × 2.5
|
Propeller 180°
|
Venous congestion
|
|
2
|
83/Male
|
BCC
|
Sidewall
|
3.1 × 3.0
|
V-Y
|
None
|
|
3
|
78/Male
|
BCC
|
Sidewall
|
2.8 × 2.5
|
V-Y
|
None
|
|
4
|
85/Female
|
BCC
|
Ala
|
2.5 × 3.2
|
Propeller 180°
|
None
|
|
5
|
70/Male
|
BCC
|
Sidewall
|
3.0 × 3.0
|
V-Y
|
None
|
|
6
|
85/Male
|
BCC
|
Sidewall
|
2.5 × 3.2
|
V-Y
|
None
|
|
7
|
74/Male
|
BCC
|
Ala
|
2.0 × 2.0
|
Propeller 180°
|
Pin cushioning
|
|
8
|
73/Male
|
BCC
|
Ala
|
2.0 × 1.9
|
Propeller 180°
|
None
|
|
9
|
83/Male
|
BCC
|
Sidewall
|
3.0 × 2.5
|
V-Y
|
None
|
|
10
|
87/Male
|
BCC
|
Ala
|
2.5 × 3.2
|
Propeller 180°
|
None
|
Case 1
An 81-year-old woman underwent excision of a BCC in the left ala nasi. Following resection
of the cancer, a perforator from the LNA was used to reconstruct the defect. A 180°
rotation island flap 2 cm in width and 5 cm in length was designed. The aesthetic
unit was restored. The location of the perforator corresponded to our cadaveric study.
No complications were noted ([Fig. 4]).
Fig. 4 Case 1
A 75-year-old woman with basal cell carcinoma. (A) The excision and flap design area
were marked. (B) Tumor excision and reconstruction with a 180° propeller flap after
the individuation of the lateral nasal artery perforator. (C) Frontal view of the
results six months after the procedure.
Case 2
An 83-year-old man underwent excision of a BCC in the left nasal sidewall. The defect
was covered with an LNA V-Y perforator flap. Two arteries and two venous perforators
were included in this flap. The cranial part of the flap was thinned to the level
of the subdermal plexus to improve the aesthetic restoration of the nasal sidewall
unit ([Fig. 5]). The location of the perforators corresponded to that identified in our cadaveric
study.
Fig. 5 Case 2
A 78-year-old man with basal cell carcinoma. (A) The excision and flap design area
were marked. (B) Tumor excision and reconstruction with a V-Y perforator flap after
the individuation of the lateral nasal artery perforator. (C) Frontal view of the
results six months after the procedure.
Case 3
A 70-year-old man underwent excision of a BCC in the right nasal sidewall. The defect
was covered with an LNA V-Y perforator flap. Two perforators were included in this
flap ([Fig. 6]). The location of the perforators corresponded to that identified in our cadaveric
study.
Fig. 6 Case 3
A 70-year-old man with basal cell carcinoma. (A) The excision and flap design area
were marked. (B) Tumor excision and reconstruction with a V-Y perforator flap after
the individuation and isolation of the lateral nasal artery perforator. (C) Frontal
view of the results four months after the procedure.
DISCUSSION
Previous studies have investigated facial artery perforators, but have reported inconsistent
results regarding LNA perforators [[3]
[10]
[11]]. A number of authors have used LNA perforators for ala nasi and nasal sidewall
reconstruction [[5]
[6]
[7]
[8]
[9]]. However, the literature contains little information concerning the cadaveric dissection
of the LNA perforators, and most previously published studies have focused on facial
artery perforators.
Hofer et al. [[3]] and Ng et al. [[12]] showed that the distribution of perforators near the base of the ala nasi seems
to be inconsistent and reported a very low number of perforators in this anatomic
area.
However, we found an area lateral to the ala nasi where perforators were consistently
present. This was an area of approximately 1 cm2 corresponding to the upper third of the nasolabial fold lateral to the limit of the
ala nasi, before the lateral nasal artery gives off the inferior ala nasi artery branch
[[14]] ([Fig. 3]).
Although other authors [[5]
[6]
[7]
[8]
[9]] have used LNA perforator flaps for nasal reconstruction, to our knowledge, no previous
studies have described the anatomic landmarks in a way that could provide guidance
to surgeons approaching this area. Based on our cadaveric study, we were able to approach
this anatomic area with confidence. This was especially important since preoperative
Doppler imaging would not have been helpful in finding perforators due to their proximity
to the source vessel, which would have resulted in many false positives.
Nasal defects can be reconstructed through many surgical approaches, including the
forehead flap [[18]], the nasolabial flap [[19]], and various local flaps [[20]
[21]
[22]
[23]]. The nasolabial area is the ideal donor site for scar concealment in the natural
nasolabial fold. Therefore, traditional local flaps, such as nasolabial flaps, are
good solutions for nasal defect reconstruction, but they require a two-stage procedure.
The LNA perforator-based flap allows freedom in flap design, avoiding this uncomfortable
drawback, and allows nasal defects to be reconstructed in a one-stage procedure. Moreover,
the nasolabial skin can be advanced as a V-Y shaped perforator flap for nasal sidewall
reconstruction without tension or distortion, reaching the dorsum nasi with ease.
Compared to a random subcutaneous V-Y advancement flap, when the flap is islanded
on the selected perforators, it is advanced toward the defect more easily, thereby
allowing the surgeon to avoid distortion of the surrounding anatomic structures and
tension on the suture lines, which could eventually lead to distal flap necrosis [[24]].
The V-Y technique has significant vascular and aesthetic advantages in comparison
to the propeller flap design, but a propeller flap should be considered if the perforator
vessel is in close proximity to the defect [[24]]. According to our cadaveric study, the propeller flap design is the best solution
for ala nasi defects, due to the proximity of the perforators to the defect ([Fig. 3]).
While the V-Y perforator flap does not have significant disadvantages, and it has
a wider range of advancement compared to the standard subcutaneous V-Y flap, the LNA
propeller perforator flap for ala nasi reconstruction has numerous drawbacks compared
to the classic interpolated melolabial flap.
The LNA perforator propeller flap has the following advantages: (1) One-stage reconstruction
instead of a two-stage reconstruction technique; (2) The possibility of dissecting
an innervated flap; (3) Freedom in flap design and shaping, obviating the necessity
to adhere to the length-to-width ratio previously considered necessary to ensure viability.
However, the LNA perforator propeller flap has the following disadvantages: (1) Difficult
dissection due to the small vessel dimensions, even if the intramuscular course is
limited; (2) Pin-cushioning deformity is more frequent in these small perforator flaps
compared to the classic interpolated melolabial flap, and the subunit reconstruction
is less accurate; (3) Venous congestion can easily occur due to twisting of the vessels,
even if the perforator is dissected with a small cuff of surrounding fatty tissue.
Ala nasi reconstruction is a challenging surgical procedure due to the peculiar shape
of the ala nasi and because it is desirable to achieve symmetry with the contralateral
ala nasi.
In young patients without comorbidities, the classic two-stage procedure is optimal
in terms of cosmetic results and because it reduces the risk of complications. However,
in certain cases, such as elderly patients in whom is preferable to avoid multiple
surgical procedures due to anesthesia-associated risks, the LNA propeller flap is
an excellent one-stage reconstructive procedure, and our experience suggests that
this technique can be successfully applied with acceptable cosmetic results.
LNA perforator flaps are reliable and versatile flaps for reconstruction of the ala
nasi and the sidewall of the nose. Our cadaveric study allowed us to identify an area
in the upper third of the nasolabial groove with a high density of perforators. This
allows a more confident approach to this anatomic area, since preoperative Doppler
would not be helpful in finding perforators.
