BACKGROUND: soft tissue coverage is extremely challenging3; due

BACKGROUND:

Soft tissues injuries at foot especially at heel expose the
tendons, bones and especially joints, which leads to risk of infections and
necrosis. These often result from trauma (spoke wheel), tumors, and chronic
diseases such as peripheral vascular disease and diabetes. Surgical planning of
these defects remains a challenge due to shortage of local scar free tissue and
reliable blood supply. The present study aims to prospectively evaluate the
outcome of distally based sural flap for coverage of defects of dorsum
of foot, ankle & heel.

 

MATERIAL
&METHODS:

This study was conducted at Department of
Plastic & Reconstructive Surgery, Dr. Ruth KM Pfau Civil Hospital Karachi
from January 2015 to January 2018. All patients who presented with wounds at
heel, dorsum of foot, and exposed calcaneus or Achilles tendon were included. A
peroneal based perforator identified by hand held Doppler, a superficial vein,
and the vascular axis of the sural nerve were
included in the pedicle. Patients were followed during the first 6
postoperative months. Complications like venous congestion, tip necrosis and
partial and complete flap failure were documented. A peroneal based perforator identified by hand held
Doppler, a superficial vein, and the vascular axis of the sural nerve were included in the pedicle.

 

RESULTS:

Total of 36 reverse low sural flaps were
done for the soft tissue coverage of the 24 heel defects, 8 ankle defects and 4
dorsum of the foot defects. Twenty eight patients were male and eight
were females and age ranged from 6 to 36 (mean 21) years. Partial flap failure was seen in 4 cases and complete
flap failure in 3 cases. There were no serious donor site complications and all
patients were satisfied with the functional and aesthetic outcome
postoperatively.

 

CONCLUSION:

Distally based sural artery flap is very useful in covering the defects
of heel and dorsum of foot. It is reliable, easy to harvest with minimal
morbidity to the patient. This flap is Safe because it does not sacrifice any
of the major vessels of the limb.

 

KEYWORDS: Calcaneus fractures, peroneal artery based perforator, Achilles
tendon, sural artery flap.

 

 

 

 

 

 

 

 

 

 

 

INTRODUCTION:

 

Due to
recent urbanization, an increase in high velocity trauma, compound fractures,
extensive degloving injuries and poly-trauma have become more frequent1, 2.
Complete soft tissue coverage is extremely challenging3; due to
unreliable blood supply after traumatic injury and thin subcutaneous tissue
over the lower leg, heel and malleolus. As trauma and other degloving injuries
often involve skin & subcutaneous tissue, underlying bone, ligamentous
structures& exposes the tendon and bones directly4, which leads
to risk of infections and necrosis. Soft tissue injuries and defects in the
lower extremity often result from trauma, tumors, and chronic diseases such as
peripheral vascular disease and diabetes. Lower extremity trauma most often
occurs after motorcycle or car accidents and frequently involves tibia. Spoke
wheel injuries lies among the most common injuries in motorcycle riders. This
kind of injury commonly occurs when foot gets struck in between the spokes of
the wheel. The malignant tumors arising from the skeleton frequently involves
the tibia. Resection of the tumors with safe margins often results in large
defects with exposed bone, tendon or neurovascular structures; moreover
irradiation of the surrounding tissue makes doubtful primary closure. Chronic
wounds of the lower extremity often involve the foot and ankle and are the
result of minor trauma in patients with co-morbidities like diabetes,
peripheral vascular disease, and venous hypertension.  Reconstruction of these defects with soft
tissue coverage also demands for fat padding of calcaneus as it is the primary
weight bearing bone transferred from the tibia. Grading system that determines
the extent of tissue damage: Type I: Skin
loss with no exposure of bone or tendon. Type II: Skin loss with Achilles tendon either exposed or ruptured. Type III: Skin loss with Achilles tendon
defect, calcaneus exposed or fractured. Type IV: Mangled foot with damage to neurovascular bundles10.

 

There
are many possible reconstructive options, including skin grafts, local flaps,
distant flaps and free flaps5, 6. Skin grafts are not suitable to
cover the exposed bone, tendon, malleoli, heel, and weight bearing areas7,
8. Absence of peripheral pulses, presence of adjacent scarred skin and
peripheral vascular thrombosis are contraindications to local flaps; being at
the top of reconstructive ladder free tissue transfers provide excellent tissue
coverage9 but require a microvascular team and equipment. Raising a
flap with an intact neurovascular anatomy with a fair amount of mobility to
cover a defect at a considerable distance is the key to a successful
rehabilitation. It is equally important to consider a meticulous dissection for
achieving minimum donor site morbidity & related complications.

 

This
study was conducted to evaluate the outcome of
reverse sural flap for the coverage of ankle, heel and dorsum of
foot defects.

 

MATERIAL
AND METHODS:

 

This descriptive,
experimental study was conducted at Department of Plastic and Reconstructive Surgery, Dr. Ruth KM Pfau Civil Hospital Karachi, from January 2015 to January
2018. It included 36 patients; 28 were males and 8 were females, with soft
tissue defects of the heel, ankle and dorsum of foot. The age, gender, cause,
duration, site and size of the defect, dimension of flap, transposition of
pedicle (through a tunnel or lay open), postoperative results and complications
were recorded. X-rays of the recipient site were done in all cases to evaluate
the condition of the underlying bone and to rule out osteomyelitis. Patients
with calcaneus fractures, external fixator application, and osteomyelitis, and
peripheral vascular disease, traumatic or irradiated tissue adjacent to wound
were excluded.  Patients with trauma in
zone of peroneal artery perforators were also excluded from study. Repeated
debridement and dressings of the wounds were performed until the wound was
ready for further management.

 

All
patients were followed in outpatient clinic for flap outcome and complications for
6 months. Total flap loss was considered as major complications.

 

SURGICAL TECHNIQUE

Patient
was laid in standard lateral or prone position under general or spinal anesthesia
and tourniquet control. Recipient site was debrided before harvesting the flap.
Planning in-reverse was done. Pivot point of the flap was kept at a distance of
5–6 centimeters from the lower end of lateral malleolus. Hand held Doppler ultrasound
was used for the assessment of perforators. The junction of proximal and middle
third of the leg was considered upper limit for the flap whereas patients’ who
required longer pedicle the flap was required to be placed in proximal third of
leg using delay phenomenon first in minor OT room under local anesthesia and
then the elevation and inset of flap was done after 10 days. The skin island
was incised down to the level of the fascia. The sural nerve was divided proximally,
ligated and buried between muscles and the short saphenous vein and sural
artery was ligated. Dissection was done from proximal to distal fashion. In
majority of patients skin island was passed through a wide subcutaneous tunnel
into the defect (Fig 1) while in some patients an open passage was
created for the flap by incising the skin bridge between the donor and
recipient area hence no tunneling was done (Fig
2) and pedicle was then divided after 3 weeks.  Tourniquet was released to check the
vascularity of flap and control of bleeding.

 

Donor
area was covered with split thickness skin graft in all the cases and the flap
was inset on the recipient area with help of Prolene 3/0  (Ethicon Inc., Cornelia, Georgia, USA) or skin
staples. Dorsal slab was given to all patients. Postoperatively
patients were laid in lateral position with elevation of operated limb to
alleviate pressure from the perforator. Weight bearing was allowed after 4–6
weeks.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESULTS:

 

Total 36 patients were included in the
study with defect in the heel in 24 patients, at ankle in 8 patients and at
dorsum of foot in 4 patients. The dimensions of the defect ranged from 5–12 cm
in length and 4- 10 cm in width. Duration of the defect was from 2 weeks to 2
months.

 

In 26
patients the junction of proximal and middle third of the leg was considered
upper limit for the flap where as in 10 patients proximal third of leg was
taken as upper limit using delay phenomenon.

 

In 30 patients;
skin Island was tunneled, while in 6 patients flap was interpolated between
donor and recipient areas. (Table-1)

 

Twenty nine flaps survived without any
complications. Complete failure of flap in 3 cases and compression at the site
was found to be the main cause, while 4 flaps showed partial failure which was
skin grafted later (Fig 3). On an average total
hospital stay was around one week.

 

Dorsal splint was provided for 3 weeks
and average healing time was 4 weeks. There was no incidence of any neuroma
formation or any flap donor site complications. Graft donor site; mostly thigh,
also showed no major complication. No patient had difficulty in walking and
weight bearing on the operated limb after 3 months.

 

DISCUSSION:

 

As Skin graft is easiest option to cover
a wound but cannot be used on exposed tendons, bones. Local flaps may not be feasible
because of limited flap mobilization and arc of rotation11. Free
flaps provide reliable and excellent soft tissue coverage but as it demands12prolonged
operative time and need for microsurgical expertise limits its use. More over
in developing countries costly infrastructure cannot be provided at every
hospital.

Hence sural fasciocutaneous and
adipofascial flaps provide easy reconstruction option in our setup. In fact there
has been a renewed interest in local flaps because of pedicle perforator flaps13.

 

The reverse sural artery flap was first described
by Donski and Fogdestam and later popularized by Masquelet et al.13, 14 The anterograde blood supply to sural angiosome
arises from median, medial and lateral superficial sural arteries. However this
flap has retrograde blood supply from fasciocutaneous perforators of peroneal artery15.
This flap also gets blood supply from perforators of posterior tibial artery.
Additionally neurocutaneous perforators from small arteries accompanying sural
nerve and venocutaneous perforators from small arteries accompanying short saphenous
vein supply sural flap16.

 

 Among the 7 cases that developed necrosis,
most had soft tissue defects over the ankle, dorsum of the foot; only other
case with necrosis had a diabetic ulcer over the dorsum of the foot. Thus, we
suggest that the chances of edge necrosis of the flap are higher when there is
a distal soft tissue defect, more so among patients with diabetic ulcers16,
17. Partial flap necrotic cases were treated with debridement and split
thickness skin grafting. Few patients complaint sural hypoesthesia over the
dorsolateral foot, though being reverse sural an insensate flap; none of our
patients developed a trophic ulcer. The reason for this observation demands
further research18, 19. After this flap, the surgeon is prohibited
from taking any posterolateral bone graft using Harman’s approach in case
delayed union or non-union of tibia 20.

Thus, the reverse sural fasciocutaneous flap
based on peroneal perforators with a cutaneous pedicle or noncutaneous pedicle
is a quick, easy and versatile technique requiring no microvascular repair.
However, there is no substitute for a meticulous dissection for achieving
minimum donor site morbidity & related complications.  

 

 

 

CONCLUSION:

 

Almost all the patients continued their
daily activities three months after the surgery; it shows distally based sural
artery flap is a versatile & reliable option for the coverage of soft
tissue defects of the distal lower extremity and the results are uniformly
acceptable with minor complication rates.