Keywords
square flap - Z-plasty - burn - contractures - scar
Introduction
The square flap method was originally described by Hyakusoku in 1987. It is considered
a type of local flap that combines transposition and advancement technique that is
appropriate for the correction of a single, linear contracture band.[1] The square flap method has been successfully used as an effective way to release
band contractures at various locations involving axilla, elbow, and digital web spaces.[2]
[3] However, the original square flap method alone may not be efficient enough to release
the whole band in cases of long-scar contracture bands. We, therefore, proposed an
extended design to the traditional square flap method, which is called “square-plus
flap.”
Idea
A 4-year-old girl presented to our clinic with a postburn web-like axillary contracture
band involving the right anterior axillary fold. The preoperative contracture band
length was 11 cm and the degree of abduction was 120 degrees. We found that an application
of a classic square flap method alone is not adequate to release a relatively long,
linear contracture band. We, therefore, decided to extend the design of the traditional
square flap.
The contracture band was divided into three equal parts, the central part was used
for the square flap method and the two lateral parts were used for Z-plasties. Along
the center of the contracture band, we marked a square on one side of the contracture
and two triangular flaps on the other side of the contracture. The angle of the first
triangular flap and the second flap were kept at 45 and 90 degrees, respectively,
while the angles of the two Z-plasties were 45 degrees. The lengths of the square
sides, triangular flaps, and Z-plasty limbs were kept equal.
A full-thickness skin incision was made at first along the marked square flap design,
followed by an incision in the subcutaneous tissue, and all contracted scar tissue
was released. After release, the square flap was advanced across the contracture area,
and the adjoining triangular flaps were transposed and then placed proximally and
distally on each side of the square advancement flap. Following securing the square
flap, we assessed the efficacy of elongation of the contracture band and thereafter
decided to proceed with the addition of Z-plasty in order to release any residual
contracture. The adjacent distal Z-plasty was then incised, transposed, and sutured
in their new locations ([Fig. 1]). In our illustrated clinical case, we did not need to incise the proximal Z-plasty
as we could effectively achieve complete relaxation and elongation of the contracture
band. The postoperative contracture band length was 14 cm when we used the square
flap method alone and the length was increased to 15.5 cm with the addition of distal
Z-plasty. Also, the degree of abduction was improved from 120 degrees preoperatively
to 180 degrees postoperatively.
Fig. 1 (A) Long contracture band over right anterior axillary line and square flap design.
(B) Addition of double opposing Z-plasty on either side of the square flap. (C) After the square flap was advanced and the adjoining triangular flaps were positioned
on each side of the square flap. (D) Adjacent distal Z-plasty was then incised, transposed, and sutured in their new
locations. (E) A follow-up picture at 6 weeks postoperatively.
Discussion
We developed a new modification of the square flap method, combining a single square
flap plus one or two opposing Z-plasties. This modification is generally applicable
to release long postburn scar contractures. The standard square flap method is a type
of local flap that is appropriate for the surgical release of a single, linear band
contracture at various locations that have adjacent healthy tissue.[2] Classically, it consists of a square advancement flap incorporated with two triangular
transposition flaps.
The square flap method has been demonstrated to be suitable for Kurtzman type IIa
and IIb axillary web scar contractures.[2]
[4]
[5] Also, it possesses numerous advantages, particularly in web-like contracture release
involving the axilla, it adequately restores the original web architecture, provides
the largest vascularized flap area with the least physiological tension, and delivers
better lengthening when compared with other Z-plasties.[6]
However, when used to release a long contracture band, utilization of a single large
flap is susceptible to excessive transverse tension which may be associated with wound
dehiscence or ischemic tissue necrosis. To avoid these problems, we introduce a square
plus modification which includes the addition of two Z-plasties on both sides to the
classically designed square flap. In our technique, following insetting of the traditional
square flap, we assessed the efficacy of elongation of the band provided by the square
flap alone and we then decided to proceed with using either single or double Z-plasties
in order to overcome any residual contracture and provide more length gain. In our
illustrated clinical case, we could effectively achieve complete relaxation and elongation
of the contracture band from 11 cm preoperatively to 14 cm postoperatively when we
used the square flap method alone. However, the gain in length of the contracture
band was further increased to 15.5 cm with the addition of distal Z-plasty. This indicates
further improvement in the length gain of the contracture band with the addition of
Z-plasties to the traditional square flap method. We classified the modified square
plus method into type IA which involves the addition of one Z-plasty proximal to the
designed square flap, type IB involves the addition of one Z-plasty distal to the
designed square flap, and type II which includes the addition of double opposing Z-plasty
on either side of the designed square flap ([Fig. 2]; [Table 1]). The application of square plus flap in this consequently is effective in releasing
long postburn scar contractures that provide suitable lengthening with lesser transverse
tension.
Fig. 2 (A) Square-plus flap type IA: addition of one Z-plasty proximal to the designed square
flap. (B) Square-plus flap type IB: addition of one Z-plasty distal to the designed square
flap. (C) Square-plus flap type II: addition of double opposing Z-plasty on either side of
the square flap.
Table 1
Classification of square plus flap
|
Square-plus flap types
|
|
|
Type IA
|
Addition of one Z-plasty proximal to the designed square flap
|
|
Type IB
|
Addition of one Z-plasty distal to the designed square flap
|
|
Type II
|
Addition of double opposing Z-plasty on either side of the square flap
|
We believe that our modification is a more reliable and versatile method than commonly
described Z-plasty techniques, such as Z-plasties in series, seven- and nine-flap
Z-plasties, in long-scar contracture release, which gives good lengthening with lesser
transverse tension. By using our proposed technique, we preserve the advantage of
the square flap which accurately reproduces the original axillary web architecture
with better lengthening and avoids tip necrosis that is associated with multiple Z-plasty
techniques, especially in scarred skin. However, long-term follow-up is needed in
order to confirm the efficiency of this modification.
This novel modification can be added to the plastic surgeon's armamentarium for releasing
long postburn contracture bands involving distinct body regions.
