Keywords ulnar artery - arterial injury - doppler - arterial patency - arterial repair
Introduction
Arterial injury of the forearm accounts for 50% of peripheral vascular lesions.[1 ]
[2 ] These injuries commonly involve penetrating or blunt/penetrating trauma, with the
highest incidence occurring in the young male population due to penetrating glass
injury.[3 ]
[4 ]
Generally, associated lesions are present in musculotendinous structures. Orthopedic
and neurological injuries occur more frequently as a result of blunt trauma.[5 ]
[6 ]
The diagnosis of arterial injury can be made through a clinical evaluation; the symptoms
include hemorrhage, ischemia, and accompanying neurological deficits due to the proximity
of the nerves to arteries. Complementary imaging examinations are indicated when the
clinical signs cannot confirm the existence or location of an arterial injury[5 ]
[6 ]
Clinical evaluation tests, such as palpation of the arterial pulse, the Allen test,
and handheld Doppler examination, can be used to assess arterial patency. Doppler
ultrasonography can be used for the evaluation as an imaging test.[5 ]
In the Allen test, the examiner occludes the radial and ulnar arteries by digital
compression and then asks the patient to open and close his or her hand to drain the
blood from the palmar arch. The patient then relaxes his or her hand, and the examiner
stops compressing the artery to be evaluated, observing the time required for the
color of the palm to return to normal. The test is considered positive when the artery
is patent, showing a return to normal color in less than 6 seconds.[1 ]
Doppler ultrasonography has an accuracy of ∼ 98% in diagnosing arterial obstruction
and is considered a low-cost and noninvasive test. This test is more specific than
sensitive, and it is time consuming and examiner dependent.[4 ]
One complication associated with repair is vessel thrombosis, which leads to treatment
failure. The rate of patency after individual repair of the radial or ulnar artery
using microsurgical techniques ranges from ∼ 46 to 84%.[4 ] The highest success rates are observed in injuries repaired within 36 hours, injuries
caused by sharp objects (not by avulsion or laceration), and injuries to the radial
artery.[4 ]
Due to the potential for thrombosis, as previously reported for arterial repairs,
we decided to perform clinical evaluations and use diagnostic tests (Doppler ultrasound)
to evaluate patients who underwent emergency surgery to check arterial patency and
propose clinical evaluation as an alternative to Doppler ultrasonography.
Materials and Methods
Patients with injuries of the volar zone V of the forearm with an associated arterial
injury underwent primary repair of the injury and were followed up with clinical and
ultrasonography evaluations at the Clinics Hospital of the Faculdade de Medicina de
Ribeirão Preto da Universidade de São Paulo from May 2018 to September 2019.
Patients who underwent ligation of the injured artery or with the need for graft interposition
to repair the artery were excluded.
Of the 33 patients selected, 15 did not complete follow-up at the clinic, that is,
did not return for the visits and did not undergo the appropriate evaluations. Eighteen
patients had all of the information necessary for the study, and most men (72%) were
young, with an average age of 30 years (range, 16–60 years), without diseases.
The patients returned for a follow-up visit at 1 week to evaluate the dressing and
at 4 weeks to assess the range of motion, when they presented with an associated tendon
lesion, and for evaluation of arterial flow using the Allen test and a handheld Doppler
device ([Figs. 1 ] and [2 ]). At ∼ 12 weeks after the injury, the patients were evaluated using Doppler ultrasonography,
and at ∼ 14 to 16 weeks after the injury, they were reevaluated using the Allen test
and handheld Doppler device.
Fig. 1 Handheld Doppler device used to evaluate the patients.
Fig. 2 Assessment of a patient using a handheld Doppler device.
The most frequent trauma mechanism was penetrating trauma, accounting for ∼ 78% of
cases, whereas in 22% of cases, the mechanism was blunt/penetrating trauma, such as
work accidents.
The most commonly used suture was polypropylene (88%), and nylon was used in 12% of
cases, based on the surgeon's choice.
All repairs were performed using loupes, with loupes with up to 3.5× magnification
used in 9 cases and loupes with 4 to 6× magnification used in 9 cases. All surgeries
were performed in an identical manner by two surgeons who were at the end of their
hand surgery training and under the tutelage of the senior author.
Seventy-seven percent of the patients underwent arteriorrhaphy within 120 hours (5
days) of the injury, with an average duration of 82 hours (∼ 3 days after injury).
A descriptive statistical analysis of the data was performed. The Student t -test, Fisher[7 ] exact test, and McNemar test were used, and all statistical analyses were performed
using the statistical software SAS 9.4 (SAS Institute Inc., Cary, NC, USA).[7 ]
[8 ]
[9 ]
The current study was approved by the Ethics in Human Research Committee, and all
participants provided written informed consent.
Results
At the first clinical evaluation (∼ 4 weeks after the injury), 77% of the patients
showed patency based on the Allen test, and the pulse was identified in 72% of patients
using a handheld Doppler device ([Figs. 1 ] and [2 ]).
At the second clinical evaluation (∼ 14–16 weeks after the injury), 61% of the patients
had patency based on the Allen test, and the rate of pulse identification by the handheld
Doppler device remained at 72%, as observed 2 months earlier.
The Doppler ultrasonography evaluation (∼ 12 weeks after the injury) indicated an
arteriorrhaphy success rate of 88%. Regarding the final patency (evaluation using
Doppler ultrasonography) and the trauma mechanism, all patients with penetrating trauma
had patent arteries, and in patients with blunt/penetrating trauma, the success rate
was 85% (p -value: 1.0).
All patients who underwent arteriorrhaphy using nylon sutures showed patent arteries
in the final evaluation, and among patients who underwent arteriorrhaphy using polypropylene,
87% showed patency via Doppler ultrasonography (p -value: 1.0).
All surgeries were performed by magnification using loupes during the repair, that
is, 3.5× or 4 × , and there was no difference between the groups (p -value: 1.0) and between the surgeons.
All patients who underwent repair within 5 days had patent arteries in the final evaluation,
and the patency rate for patients with late arteriorrhaphy was 50% (p -value: 0.03) ([Table 1 ]). All patients for whom the Allen test at the first clinical evaluation (4 weeks)
showed patent arteries had patent arteries at the final ultrasound evaluation. Of
the patients with negative Allen test results (occluded artery) at the first clinical
evaluation, only 50% had patent arteries at the final Doppler ultrasonography evaluation
(p -value: 0.03) ([Fig. 3 ]). In the second clinical evaluation (14–16 weeks), agreement of the Allen test with
the ultrasonography evaluation remained at 100% for patients with patent arteries
based on the Allen test, but the agreement rate decreased to 28% for patients with
a negative Allen test (p -value: 0.13) ([Fig. 4 ]).
Fig. 3 Comparison of the initial Allen test with the final ultrasonography evaluation.
Fig. 4 Comparison of the Allen test in the second evaluation with the final ultrasonography
evaluation.
Table 1
INTERVAL
DOPPLER
Total
Non- patent
Patent
up to 120 hours
0
0.00
14
77.78
14
77.78
> 120 hours
2
11.11
2
11.11
4
22.22
Total
2
11.11
16
88.89
18
100.00
Handheld Doppler examination performed during the first clinical evaluation also showed
100% agreement with the ultrasonography evaluation in patients with patent arteries
and 40% agreement when the pulse was not located (p -value: 0.06). These parameters were maintained in the second clinical evaluation
([Fig. 5 ]).
Fig. 5 Comparison of the initial handheld Doppler evaluation and final ultrasonography evaluation.
Discussion
Treatment of arterial injuries can be performed through ligature of the artery, primary
repair (in lesions with gaps smaller than 2 cm and good mobility of the stumps for
nontension sutures) or repair with graft interposition (in lesions with gaps greater
than 2 cm).[10 ]
[11 ]
When both arteries (radial and ulnar) are injured, even in cases with a well-perfused
hand, arterial repair should be performed to decrease ischemic symptoms.[1 ]
[4 ] Some studies have shown that the loss of perfusion through the radial or ulnar artery
to the hand can lead to cold intolerance, muscle and bone atrophy, and loss of strength,[12 ] which confirms the importance of performing arterial repair and ensuring patency
even in single-artery injuries with a well-perfused hand.
When an associated neurological lesion is present, an important gain in recovery is
observed when artery patency is achieved after arterial repair. According to the literature,
87% of patients with ulnar nerve injuries achieved adequate and excellent neurological
recovery when the ulnar artery was patent; the rate of good results decreased to 33%
in patients with an obliterated ulnar artery.[5 ]
[12 ]
The reasons for vessel thrombosis are still not well understood, but it is hypothesized
that retrograde pressure in the palmar arch causes turbulence in the vessel and decreases
flow in the repaired artery, leading to its obstruction.[13 ]
[14 ]
Similar to the epidemiology observed in other studies, in our sample, the highest
prevalence of arterial injuries in the forearm was observed in young male patients.
Doppler ultrasonography is a noninvasive, rapid, and accurate technique to evaluate
the results of vascular repair, flow rate, and flow characteristics; the success rate
of achieving patent arteries demonstrated by Doppler ultrasonography in our study
was 88%, a rate higher than that reported in the literature, in which we found values
of up to 84%.[2 ]
[4 ] The highest success rate occurred in patients with penetrating trauma (100%) and
reached 85% in cases of penetrating/blunt trauma.
When analyzing the final patency relative to the type of sutures used, we found a
higher success rate with the use of nylon (100%) than with polypropylene (87%) sutures;
however, only two arteries were repaired with nylon (two repairs), thus resulting
in little statistical significance of the finding (p -value: 1.0). The literature shows a similar patency rate between the types of sutures,
with better biocompatibility with the use of polypropylene.[15 ]
All repairs were performed using surgical loupes, and the literature demonstrates
that the use of microsurgical techniques increases the arteriorrhaphy success rate.
Regarding the interval between injury and repair, we obtained a patency rate of 100%
for arteries repaired within 5 days ([Fig. 6 ]), with a significant decrease to 50% when the interval was greater than 5 days,
with good statistical significance for these data (p -value: 0.03). We had a high success rate even if the procedure was performed after
36 hours, unlike that reported in the literature.[4 ]
Fig. 6 Doppler ultrasonography examination showing a patent artery after arteriorrhaphy.
Regarding clinical and ultrasound evaluations, we found that both the Allen test and
the handheld Doppler evaluation were reliable for determining arterial patency when
they indicated positive results (patent artery), resulting in a high positive predictive
value. However, the Doppler ultrasonography results were not well correlated with
clinical test results showing a nonpatent artery ([Fig. 7 ]), resulting in a large number of false negatives. Our sample size was small, but
we propose that the clinical evaluations are sufficient to assess vascular repair.[4 ]
Fig. 7 Doppler ultrasonography examination showing an obstructed artery.
We conclude that clinical evaluation using a handheld Doppler device and the Allen
test is reliable when a patent artery is observed on clinical evaluation. However,
if the clinical evaluation reveals nonpatent arteries, the result must be confirmed
using ultrasonography.
