Evaluations of Repaired Artery Patency in Forearm Wounds Using the Allen Test, Handheld Doppler and Doppler Ultrasonography^[*]

Abstract

Objective The purpose of the present study was to evaluate the rate of patency in the postoperative period of arterial injuries of the forearm secondary to penetrating trauma. The injuries were subjected to primary repair and examined with the Allen test and a handheld Doppler device, and the results were later confirmed with Doppler ultrasonography.

Methods Eighteen patients were included, with a total of 19 arterial lesions, 14 ulnar lesions, and 5 radial lesions; one patient had lesions on both forearms. All patients underwent surgery and three clinical evaluations: the Allen test and assessment of arterial blood flow by a handheld Doppler device at 4 and 16 weeks after surgery and Doppler ultrasonography performed at 12 weeks after surgery.

Results At the first clinical evaluation, 77% of the patients had patency based on the Allen test, and 72% had a pulsatile sound identified by the handheld Doppler device. In the second evaluation, 61% of the patients had patency based on the Allen test, and the rate of pulsatile sound by the handheld Doppler device was 72%, similar to that observed 2 months earlier. Based on the Doppler ultrasonography evaluation (∼12 weeks after surgery), the success rate for arteriorrhaphy was 88%. Regarding the final patency (Doppler ultrasonography evaluation) and trauma mechanism, all patients with penetrating trauma had patent arteries.

Conclusion We conclude that clinical evaluation using a handheld Doppler device and the Allen test is reliable when a patent artery can be palpated. However, if a patent artery cannot be located during a clinical examination, ultrasonography may be required.

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.

Conflito de Interesses

Os autores não têm conflito de interesses a declarar.

^* Study developed at the Department of Orthopedics and Anestesiology, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

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Publication History

Received: 10 July 2020

Accepted: 03 November 2020

Article published online:
13 August 2021