15018752330
发表时间:2015-12-08 浏览次数:546次
Introduction
Soft tissue defect of the knee remains challenging and problematic to
reconstructive surgeons. Prerequisite for the reconstruction of this
region include the flexibility, durability and thickness of the skin
paddle to sustain the motion of the knee joint. Numerous surgical trials
have been performed using musculocutaneous flaps, fasciocutaneous
flaps, perforator flaps, and free flaps to repair these defects with
varying degrees of success. [1],[2],[3]
Local flaps created from the calf muscle are preferred primary surgical
option. However, local flap may not be an option when there is injury
to the donor site endangering the vascularity. Although the free flaps
are less affected in terms of the donor site selection, selection of the
recipient vessel in the vicinity of knee defect remains problematic.
Since
perforator to perforator anastomosis (supermicrosurgery) emerged, this
technique has been vastly used for reconstructive surgeries without
regard to the recipient vessel. We report a case using the superior
medial genicular perforator as the recipient vessel and
supermicrosurgery techniques to cover the soft tissue defect of the
knee.
Case report
A 24-year-old male was injured in a motorcycle accident. Patient had a knee injury with soft tissue defect measuring 12 cm × 7 cm and exposure of the patella was noted [Figure 1]. Physical examination revealed severe contusion of the posterior calf. Because of these findings, repair using local gastrocnemius musculocutaneous flap was excluded to avoid unreliable vascularity of the donor site. Instead, a free flap reconstruction using a vessel in the vicinity of the knee as the recipient was planned.
Conventional angiography instead of computed tomographic angiography was performed to predict the direction of vascular flow around the traumatized knee. It showed abrupt cutoff with retrograde filling of the superior lateral genicular perforator compared with intact superior medial genicular perforator [Figure 2]. Using the intraoperative hand-held Doppler, perforator of superior medial genicular artery was targeted and identified. Elevation of anterolateral thigh perforator free flap with 3 cm pedicle length was performed and the superior medial genicular perforator was identified under a microscope. Perforator to perforator anastomoses of one artery (0.6 mm, descending branch of lateral circumflex femoral artery with superior medial genicular artery) and two veins (0.4 mm and 0.7 mm, venae comitantes) with 10-0 and 11-0 nylon were made in an end-to-end fashion [Figure 3]. Donor site was closed with meshed allogeneic dermal matrix, followed by split thickness skin graft (0.3048 mm).
The flap survived successfully, and the patient had functional
ambulation within 15 days after surgery without any complications. Full
flexion of the knee joint was achieved by postoperative week 4. Patient
was also able to squat without any discomfort. The patient was satisfied
with the contour of the flap at postoperative month 11 [Figure 4].
Discussion
Reconstruction of soft tissue defects surrounding the knee has been
well-known for its difficulty and strenuous nature of the process.
Damage to the soft tissue around the knee can be caused by trauma,
cancer resection, and the exposure of prosthesis.
Several
musculocutaneous flaps including gastrocnemius, sartorius, vastus
medialis, and vastus lateralis flaps have been applied successfully to
cover the soft tissue defect of the knee. Other fasciocutaneous flaps,
island flaps and perforator flaps based on the sural artery, superior
lateral genicular artery, and the reverse flow of descending branch of
lateral femoral circumflex artery have also been used. [4],[5],[6]
However, bulky contour of the flap, functional impairment of the donor
site, and discomfort on ambulation due to the scar extended from the
donor site to the knee may be encountered with these flaps.
To avoid these drawbacks, several free flaps have been introduced. [7],[8],[9]
However, free flaps using the source vessels may threaten the
vascularity around the traumatized knee joint. The evolution of
microsurgical techniques has allowed surgeons to anastomose vessels
between perforators that are smaller than 0.8 mm in caliber. These
techniques are termed as supermicrosurgery. Hong and Koshima used this
refined technique on 25 soft tissue defects over knee joint and
minimized donor site morbidity. [9]
However, their promising results are extremely dependent on the
expertise of the surgeon. They preferred free style reconstruction
without identifying the recipient vessels, while they could easily find
the recipient vessels in the plane between the fascia and muscle.
In
this report, we demonstrate the use of conventional angiography to
identify superior medial genicular perforator vessel as the recipient in
this patient. To the best of our knowledge, this is the first case of
supermicrosurgical reconstruction using superior medial genicular
perforator as a recipient vessel. Although this procedure is technically
demanding, the use of conventional angiography to identify the
recipient vessels made it less tasking. Compared to conventional local
flap modalities, this technique creates less scarring, providing better
contour of the knee and decreased discomfort on ambulation. The patient
could flex the knee joint fully and perform exercises such as squats
without any discomfort in four weeks.
Further investigation with
larger cases should be performed for validation. Nevertheless, this case
implies the use of supermicrosurgical techniques and superior medial
genicular perforator as an alternative to repair soft tissue defect
surrounding the knee when the conservative local flap technique may not
be reliable.
References
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2.Liu TY, Jeng SF, Yang JC, Shih HS, Chen CC, Hsieh CH. Reconstruction of the skin defect of the knee using a reverse anterolateral thigh island flap: cases report. Ann Plast Surg 2010;64:198-201.
3.Fujiwara T, Chen CC, Ghetu N, Jeng SF, Kuo YR. Antegrade anterolateral thigh perforator flap advancement for soft-tissue reconstruction of the knee: case report. Microsurgery 2010;30:549-52.
4.Heo C, Eun S, Bae R, Minn K. Distally based anterolateral-thigh (ALT) flap with the aid of multidetector computed tomography. J Plast Reconstr Aesthet Surg 2010;63:e465-8.
5.Dai J, Chai Y, Wang C, Wen G. Proximal-based saphenous neurocutaneous flaps: a novel tool for reconstructive surgery in the proximal lower leg and knee. J Reconstr Microsurg 2013;29:373-8.
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7.Kim JS, Lee HS, Jang PY, Choi TH, Lee KS, Kim NG. Use of the descending branch of lateral circumflex femoral artery as a recipient pedicle for coverage of a knee defect with free flap: anatomical and clinical study. Microsurgery 2010;30:32-6.
8.Fang T, Zhang EW, Lineaweaver WC, Zhang F. Recipient vessels in the free flap reconstruction around the knee. Ann Plast Surg 2013;71:429-33.
9.Hong JP, Koshima I. Using perforators as recipient vessels (supermicrosurgery) for free flap reconstruction of the knee region. Ann Plast Surg 2010;64:291-3.