INTRODUCTION
Chronic median nerve injuries represent a major
clinical problem associated with unpredictable
final outcome and multiple manifestations especially
pain. The problem can be presented even
after median nerve repair, carpal tunnel release or
untreated median nerve injury [1].
Persistence of symptoms or recurrence of carpal
tunnel syndrome (CTS) is frequent after surgical
treatment soft tissue adhesions to the nerve, interstitial
scar, and epineurial fibrosis are common
causes of the recurrent CTS. Many treatments had
been described well in literature; the aim of treatments
was to improve quality of life by minimizing
pain with maintenance of median nerve function.
233
Neurolysis is often the first attempt, but it does
not always relieve the pain [1,2].
Reconstruction by vascularized tissue coverage
had been described for treatment of chronic pain
associated with median nerve injury. Authors described
coverage by pedicled flaps or free flaps,
all techniques of coverage to allow smooth gliding
coverage, prevent adhesion, minimize scaring and
protect nerve from trauma [2,3].
One of most successful treatment is use of
adipofascial radial artery perforator flap. The flap
is a good choice for treatment of chronic pain
associated with median nerve injury. The flap is
supplied by the septocutaneous perforators of the
radial artery which emerges in the distal forearm
in the septum between the flexor carpi radialis and
the brachioradialis tendons [1,4]. The flap gives
about ten small perforating vessels with diameters
between 0.3 and 0.9mm [5,6,7]. These vessels arise
approximately 1.5cm proximally to the radial styloid
and proximally at intervals of 0.4 to 1.5cm
[8]. A rich venous plexus accompanies this arterial
network. The cadaveric studies for the anatomy of
radial artery perforator in the distal forearm resulted
in finding 2-3 significant perforators within 2cm
from the radial styloid process in majority of cases
[9-12].
This study was conducted to study benefit of
vascularized wrapping of median nerve by adipofascial
radial artery perforator flap.
PATIENTS AND METHODS
This prospective study was conducted from
august, 2015 to March, 2017 after approval of
Institutional Review Board (IRB) of Mansoura
Faculty of Medicine (code no. R/16.06.51). Written
informed consents were obtained from 15 patients
with recurrent or persistent pain and numbness
over the area of distribution of the median nerve
lasting for six months after carpal tunnel release.
Patient with chronic debilitating disease, trauma
to the radial artery and patients with other neurological
deficit were excluded from the study.
Proper history was taken, nerve examination
was done, Nerve conduction velocity and electromyography
was done and 2 point discrimination
to the index finger was recorded. Patients were
asked to score their pain according to visual analogue
pain score and to answer the disabilities of
the arm, shoulder and hand score (quick DASH)
[21].
Hand held Doppler ultrasound was used to
roughly locate the perforator but it was difficult
in most cases to distinguish between the artery and
the perforator, general Anesthesia was used in all
patients. The arm was exanguated by gravity and
tourniquet inflated and the arm is fully extended
on side table (Fig. A1).
First, Incising the ulnar side of the flap in a
subfascial plane in a radial direction exploring
both median nerve and main trunk of the radial
artery (Fig. A2,3,4).
Adhesiolysis of the median nerve was done
both from the superficial and deep surfaces leaving
the nerve completely free with preserving the
palmar cutaneous branch, internal neurolysis was
done in all patients releasing the tethered epineurium
(Fig. A5-8).
Distal perforators from the radial artery were
identified and dissected from the intermuscular
234 Vol. 42, No. 2 / Tubed Adipofascial Radial Artery Perforator Flap for Recurrent
septum and selection of the largest perforator to
raise the flap on with ligation of the remaining
perforator (Fig. A9).
A suprafascial dissection was done from ulnar
to radial direction with preserving only 1-2mm
beneath the dermis, dissection continued till the
radial side of the flap is reached and then completing
flap elevation preserving both cephalic vein
and superficial radial nerve which were not included
in the flap (Fig. A10).
The tourniquet was released then the viability
of the flap was assessed and hemostasis was done,
this is technical refinement of the originally described
flap by sliding the flap underneath the
median nerve without rotation. The flap was
wrapped around the nerve to be sutured to the other
edge of the flap creating a vascularized tube around
the nerve (Fig. 11).
Further stitches were taken to the distal end of
the flap to the remnants of the flexor retinaculum
and between the proximal end of the flap and the
muscles to maintain the length of the flap (Fig.
A12).
Primary closure of the wound was done and
the hand was put in a static wrist splint with allowing
free fingers motion for 10 days (Fig. A13).
Patients were followed-up for one year postoperatively
and all preoperative assessments were
repeated and recorded, all data were expressed as
mean ± Standard deviation (SD). Statistics analysis
of data was carried out by IBM® SPSS® Statistics
Version 20 for Windows 7 Home Edition using
Chi-Square Tests, c2-tests. A p-value of <0.05 was
considered statistically significant.
Fig. (A1) Fig. (A2)
Egypt, J. Plast. Reconstr. Surg., July 2018 235
Fig. (A3) Fig. (A4)
Fig. (A5) Fig. (A6)
Fig. (A7) Fig. (A8)
Fig. (A9) Fig. (A10)
RESULTS
A total of fifteen patients underwent coverage
of median nerve with adipofascial radial artery
perforator flap. Three of them were males (20%)
and twelve were females (80%). Their age range
was 23-49 years (mean 36±11 years), and time
elapsed since the last operation was between 8.5±
2.01 month.
The flap dimensions (length was between 9-14
cm and width was 3.5-5cm). Mean surface area of
the flap was 32±13cm2; the largest flap was 14 x
5cm.
Number of distal perforators was two in eleven
patients were found within 2cm of the styloid
process and three perforators existed in four patients.
All of our patients, the flap was raised
dependent on a single perforator.
Fourteen patients had –ve Tinel sign on the
first dressing two days post operatively, one patient
had persistent Tinel sign for one month postoperatively.
The mean value of visual analoge scale
decreased significantly from 9 preoperatively to
236 Vol. 42, No. 2 / Tubed Adipofascial Radial Artery Perforator Flap for Recurrent
1.2 at the end of follow-up period. Both motor and
sensory latency were improved significantly towards
normal value (Table 1), 2 point discrimination
regain to near normal value, grip strength
increased to about 20kg and tip pinch test increased
to about 7kg (Table 1). Score of quick disabilities
of the arm and shoulder (DASH score) improved
from 53±12 preoperatively to 31±7. Sever affection
in the compound action potential of abductor pollicis
brevis was noted in four patients preoperatively
with reappearance of normal compound action
potential after one year.
Table (1): Results preoperatively and postoperatively.
VAS
Motor latency
Sensory latency
2 point discrimination
Grip strength
Tip pinch strength
9
5.42±0.56
4.59±0.72
11.1±0.2 mm
12.7± 2.4 kg
3.9±0.6 kg
Preoperative
1.2
3.6±0.4
3.04±0.38
5.1±0.1 mm
19±3.9 kg
6.8±1.8 kg
Postoperative
Fig. (A): A1: The median nerve was marked in white,
proposed incision in dotted black. A2,3: Dissection begin in
a subdermal direction leaving only 1 to 2mm of subcutaneous
fat and Elevation of the adipofascial flap over the median
nerve. A4-8: Release of adhesion and Intra neural dissection.
A9: Localization of the perforator the radial side of the flap
was dissected. A10: The flap is now raised based on a single
distal perforator 2cm above the radial styloid process. A11:
This is our technical refinement of the originally described
flap by sliding the flap underneath the median nerve without
rotation. A12: The distal part of the flap was sutured to the
remnant of the flexor retinaculum and the proximal part
sutured to flexor pollicis muscle to ensure complete coverage
of the median nerve. A13: Primary closure with good colour
of the defattened skin flaps.
Fig. (A11) Fig. (A12)
Fig. (A13)
Egypt, J. Plast. Reconstr. Surg., July 2018 237
DISCUSSION
Poor results were obtained following 2ry neurolysis.
Multiple flaps was used to cover the neurolysed
median nerve aiming to provide protection
and good vascularity to the nerve as hypothenar
fat bad, palmaris brevis and abductor digiti minimi
muscle flaps [13]. Limitation of those flaps was
their limited size, limited arc of rotation and coverage
of the nerve from its palmar aspect only [14].
Reverse radial artery fascial flap was used to
cover the neurolysed median nerve by Tham et al.,
[14] with great arc of rotation and large surface
area with the problem of sacrificing the radial
artery. The flap was then modified by koshima et
al., to be adipofascial perforator flap based on the
proximal perforators with rotation of the flap to
cover the median nerve [15].
Tiengo et al., [12] in their anatomical study on
16 cadaver found more numerous distal perforator
of the radial artery with smaller diameter than the
proximal perforators however in our study the
caliber of the distal perforator was the same or
slightly larger than the proximal perforator.
Number of the distal perforator in this study
was the same as Cyr et al., [6] anatomical study
with presence of 2-3 perforators within 2cm of the
radial styloid process. In one case in our study a
significant perforator was found distal to the styloid
process.
However wrapping of median nerve by vascularized
tissue is used in many researches by facial
flaps of free tissue transfer [1,17,18]. In this clinical
series, the distal radial artery perforator adipofascial
flap was as a tube to cover, protect the nerve,
prevent adhesion and improve vascularity and
nutrition around the median nerve. The vascularized
wrapping allows coverage of long distance of nerve
allows smooth gliding and prevents adhesion
around the median nerve.
The improvement of pain and Tinel sign in this
study are in concordance with other studies using
fascial flaps [19,20]. It has advantages over other
fascial flaps and free tissue in mean of decrease
bulkiness, donor site morbidity and radial artery
harvesting. The vascularity of skin of distal forearm
in this series was not affected by flap elevation,
the wound closed primary without tension and
wound healing occurred without complications.
Conclusion:
Distal radial artery perforator adipofascial tubed
flap is very useful, easy to elevate flap to provide
360 degree protection of the median nerve with
enough size to cover all the superficial part of the
median nerve in the distal forearm. To our knowledge
this is the 1st clinical series to be done using
the distal radial artery perforator adipofascial flap
as a tube to cover, protect and prevent adhesion
around the median nerve.
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