Keywords
surgical procedures - local flap - artery - perineum - vulva
Introduction
Vulvar reconstruction after radical vulvectomy is challenging. To achieve the best
outcome, functions such as intercourse, micturition, and defecation should remain
normal and a good cosmetic appearance needs to be maintained. Various flap surgeries
are used for vulvar reconstruction, including the gracilis, gluteal fold, medial thigh,
vertical rectus abdominis myocutaneous, and pudendal thigh flaps.[1]
[2]
[3] Among the flaps presented above, flaps based on the internal pudendal artery, such
as the pudendal thigh flap and the gluteal fold V-Y advancement flap, have the advantage
of becoming a sensate flap because the pudendal nerve accompanies the internal pudendal
artery.[2]
[3]
Several musculocutaneous flaps have been introduced for vulvar reconstruction; however,
these flaps are usually very bulky and do not provide the best result after standard
vulvectomy. Since local flaps are thin and pliable, standard treatments should include
local flaps after radical vulvectomy, if possible.[4]
Flaps that can be used are limited depending on the location and size of the vulvar
defect. However, the keystone flap introduced by Behan in 2003 has no limitation in
terms of designing flaps for any location and size of defects.[5] Moreover, the success rate of this technique is not strongly impacted by the skill
of the surgeon, and this technique rarely leads to major complications, such as total
or partial flap loss.[6] While the standard keystone flap was designed to reconstruct elliptical defects,
there are various modifications in its use depending on the size and morphology of
the defect.[7]
The conventional keystone flap introduced by Behan is based on randomly located vascular
perforators, whereas the techniques described in our study used Doppler ultrasonography
to include named perforators (the anterior labial artery of the external pudendal
artery, the cutaneous branches of the obturator artery, and the posterior labial artery
of the internal pudendal artery) in the flap to create a reliable flap ([Fig. 1]).[5] Moreover, we made a flap wider than the standard keystone flap, resulting in a more
reliable and redundant flap. This enabled us to achieve a better morphology of the
labium major with extra skin. Here, we report four successful reconstruction cases
of vulvar cancer after radical vulvectomy in terms of functional and cosmetic aspects.
Fig. 1 Distribution of the arteries and pudendal nerves around the vulva and perineum. (A) Anterior labial artery of the external pudendal artery. (B) Cutaneous branches of the obturator artery. (C) Posterior labial artery of the internal pudendal artery. (D) Pudendal nerve.
Case
An 83-year-old female patient was diagnosed with bilateral squamous cell carcinoma
of the vulva. After bilateral inguinofemoral lymphadenectomy of the vulva, a radical
wide excision on the right side and partial wide excision on the left side were performed
in the gynecology department. The combined defect measured 4.5 × 10.0 cm. A 5.0-cm
wide standard keystone flap and one-arm keystone flap were designed for both the right
and left sides of the vulva, respectively. However, the defect was fully covered by
the standard keystone flap on the right side alone. The patient was discharged at
27 days after surgery without complications; the patient was satisfied with the esthetic
and functional outcomes of the vulvar reconstruction at 6 months postoperatively.
A 64-year-old female patient had bilateral squamous cell carcinoma of the vulva and
several lymph adenopathies on both the inguinal areas. Under general anesthesia, the
patient was placed on the operative table in a lithotomy position.
After lymphadenectomy of both inguinofemoral lymph nodes in the department of surgery,
an excision margin was designed. Perforators of the anterior labial artery of the
external pudendal artery, two cutaneous branches of the obturator artery, and the
posterior labial artery of the internal pudendal artery on both sides of the vulva
([Fig. 1]) were located and marked using Doppler ultrasonography. The standard keystone flap
was then designed on both sides of the vulva.
After radical wide excision of vulvar cancer, a 5.5 × 8.5-cm defect was noted. Keystone
flaps were designed for both sides of the vulva and were 5.5 cm in width, which was
the same as the width of the defect ([Fig. 2]).
Fig. 2 Case 2: Double opposing keystone flap. (A) After radical wide excision of squamous cell carcinoma. The resultant defect measured
5.5 × 8.5 cm. Perforators identified using Doppler ultrasonography, and perforator
of three arteries based on double opposing keystone flaps was designed. The flap width
was 5.5 cm, equal to the defect size, and was designed on both sides. (A, anterior labial artery of the external pudendal artery, B, cutaneous branches of the obturator artery, C, posterior labial artery of the internal pudendal artery). (B) Immediate postoperative photography.
After an incision, the deep fascia was carefully divided and the border of the flap
was undermined 1 cm upward from the deep fascia. This was followed by blunt dissection
of the tissue and preservation of the neurovascular structures. After securing enough
redundancy to make the labium major, the flap was sutured layer by layer ([Fig. 2]). At 26 months postoperatively, the patient had no problems in functions, such as
micturition, defecation, walking, and sitting and had a good cosmetic appearance of
the vulva.
A 74-year-old female patient was diagnosed with extramammary Paget's disease of the
right vulva. After radical wide excision of the right vulva in the gynecology department,
there was a defect measuring 4.7 × 7.0 cm. Since the defect was oval in shape, an
omega—Ω—variant type B keystone flap was designed. The designed flap was 6.7 cm in
width. The upper and lower arms of the flap were elevated off the deep fascia and
transposed to cover the defect ([Fig. 3]).
Fig. 3 Case 3: Omega variant keystone flap. (A) After radical wide excision of extramammary Paget's disease. The resultant defect
measured 4.7 × 7.0 cm. An omega variant keystone flap was designed. The flap width
was 6.7 cm (A, anterior labial artery of the external pudendal artery, B, cutaneous branches of the obturator artery, and C, posterior labial artery of the internal pudendal artery). (B) Immediate postoperative photography. (C) Recovery without complications at 994 days after keystone flap reconstruction.
A 70-year-old female patient was diagnosed with bilateral extramammary Paget's disease
of the vulva. She underwent inguinofemoral lymph node dissection on both sides under
general anesthesia, followed by radical wide excision. The resultant defect measured
4.5 × 18.0 cm on the right side and 4.0 × 14.0 cm on the left. Standard keystone flaps
for both vulva were designed and were 6.5 cm in width for each. After a 2.0-cm dissection
under the deep fascia, a standard keystone flap was applied to the right side, whereas
a rotational keystone flap was applied for the left side, as a rotation of the flap
was required below the defect ([Fig. 4]). At 200 days after the surgery, there were no other complaints of functional discomforts
related to micturition, defecation, walking, or sitting, and the patient was satisfied
with the esthetic result.
Fig. 4 Case 4: Standard keystone on the right side and rotational keystone flap on the left
side. (A) Immediate postoperative photography, and (B) at 350 days postsurgery photography.
Discussion
The keystone flap, introduced by Behan in 2003, can be simply designed, allowing it
to be used for any location and size of defect, and undermines only the periphery
of the flap; thus, no fine perforator dissection is needed and flap survival is relatively
reliable.[5]
The standard keystone flap was designed for the reconstruction of elliptical defects;
however, there are various modifications that can be used depending on the size and
morphology of the defect.[7] The demographic characteristics of the patients are summarized in [Table 1]. This was the case for the four case presentations mentioned in this paper where
different modifications were used depending on the size and morphology of the defect.
The schematic diagram of patients with reconstruction is presented in [Table 2].
Table 1
Demographic characteristics of the patients
|
Patient
|
Age (y)
|
Underlying disease
|
Vulvar neoplasm
|
Defect side
|
Defect size (cm)
|
Lymph node dissection
|
Surgical procedure
|
Keytone width (cm)
|
|
1
|
83
|
HTN, spinal stenosis
|
Squamous cell carcinoma
|
Both
|
4.5 × 10.0
|
+
|
Standard keystone flap
|
5.0
|
|
2
|
64
|
HTN, varicose vein
|
Squamous cell carcinoma
|
Both
|
5.5 × 8.5
|
+
|
Double opposing keystone flap
|
5.5
|
|
3
|
74
|
–
|
Extramammary Paget's disease
|
Right
|
4.7 × 7.0
|
–
|
Omega variant keystone flap
|
6.7
|
|
4
|
70
|
HL
|
Extramammary Paget's disease
|
Both
|
4.5 × 18.0 (right)
4.0 × 14.0 (left)
|
+
|
Standard keystone flap (right)
Rotational keystone flap (left)
|
6.5 (right)
6.5 (left)
|
Abbreviations: HTN, hypertension; HL, hyperlipidemia.
Table 2
Schematic diagram of vulva reconstruction using keystone flaps
|
Technique
|
Diagram
|
|
Standard keystone flap
|
|
|
Double opposing keystone flap
|
|
|
Omega variant keystone flap
|
|
|
Rotational keystone flap
(standard keystone flap [right], rotational keystone flap [left])
|
|
As previously mentioned, a standard keystone flap is a fasciocutaneous advancement
flap based on randomly located vascular perforators without the use of Doppler ultrasonography
to locate perforators. In this study, named perforators (anterior labial artery of
the external pudendal artery, cutaneous branches of the obturator artery, and posterior
labial artery of the internal pudendal artery) were located in the flap using Doppler
ultrasonography, resulting in a flap more reliable than the standard keystone flap.
A wider flap than the standard keystone flap enabled a more reliable and redundant
flap, which makes it possible to suture without tension, resulting in a good outcome
of the labium major morphology.
All of the three arteries described in the manuscript were used in the four cases.
Although multiple perforators flap can limit the arc of rotation of the flap, no significant
degree of rotation was required in vulvar reconstruction. In addition, with a slight
dissection of the deep fascia, the keystone flap was approximated to the vulvar area
to secure sufficient redundancy for covering the defect.
When performing the omega—Ω—variant type B keystone flap of case 3, as described in
the manuscript, the rotation of the upper and lower arms was required; therefore,
the upper and lower arms of the flap were elevated off the wider area of the deep
fascia compared with the other cases. To reduce tension as much as possible, deep
fascia dissection is required to the lateral margin, and subcutaneous dissection can
be added to the medial margin of the flap.
For functionally and aesthetically successful vulvar reconstruction, flaps should
be thin enough. The inguinal and para suprapubic areas are commonly used for vulvar
reconstruction because they are thin.[8] However, our cases, since inguinofemoral lymph node dissection was performed in
three out of four patients and the blood supply may not be sufficient, so inguinal
skin flap was not performed.
Flaps based on the internal pudendal artery have also been used for vulvar reconstruction.[1]
[2] Flaps based on the internal pudendal artery had difficulties in reconstructing the
upper vulva, and there is a risk of necrosis of the flap tip if the flap is lengthened.
However, the keystone flap in this study used the internal pudendal artery as the
main perforator and included two additional perforators on the upper part at the same
time. So, it could be effectively used for reconstruction on the upper part of the
vulvar.
In conclusion, the keystone flap based on perforators of three arteries has many advantages.
It is easy to design and elevate, and the survival of the flap is highly reliable,
showing low morbidity and complication rates. It seems to be more advantageous for
advanced-stage vulva cancer. The procedure is also effective in reconstructing large
defects and gives good functional results and acceptable cosmetic appearances. The
flap and scars did not seem to affect the patients during walking or sitting. The
scars were also quite well hidden. Therefore, we consider this method as our primary
choice for vulvar reconstruction.
