TRAUMATIC ANEURYSMS AND ARTERIOVENOUS FISTULA.

fistula,aneurysm, trauma, vascular surgery. Abstract ........................................................................ Posttraumatic pseudoaneurysms and arteriovenous fistula are rarely observed (1)  where time from trauma to diagnosis varies from hours to years. Because of the imminent clinical course, early operation is usually indicated to prevent very impressively the extensive consequences of an unrecognized traumatic AV malformation. They occur most commonly in the extremities and are noted most often in military casualties. (3)

Posttraumatic pseudoaneurysms and arteriovenous fistula are rarely observed (1) where time from trauma to diagnosis varies from hours to years. Because of the imminent clinical course, early operation is usually indicated to prevent very impressively the extensive consequences of an unrecognized traumatic AV malformation (2) . They occur most commonly in the extremities and are noted most often in military casualties. (3) The trauma leading to the AVM may be penetrating, blunt, postsurgical or inflammatory. A swelling with or without pulsation, loss of function or peripheral claudication of the limb are the main presenting symptoms. A bruit and trill are usually present. Color Doppler USS and CT angiography will provide the essential diagnostic information. In our research there are 12 cases of traumatic AVM in different parts of the body which are angiographically documented. The surgical procedures performed were proper identification of feeder vessels, surgical control of these vessels, excision and arterial ligation and total excision and end to end arterial anastomosis or by grafting when segmental resection is required, either by reversed autogenous vein graft or by synthetic graft remain the basic principles of therapy. The end result of the surgical operations was considered good in most of patients with restoration of normal blood flow to the affected limb.

Material and Methods:-
Retrospective clinical study was initiated in Vascular Surgery department in Misurata Central Hospital in the period of 2 years between November 2014 to October 2016. Data were collected from patients files and their previous radiological investigation including Duplex U/S, CT angiography.
Our research included 12 patients with false aneurysms, 10 of them in the extremity and two patients (1 in Superficial temporal artery & 1 in arch of aorta). Eleven patients were males and one patient was female, age range was 3 to 34 years with a mean of 21.3 years. The cause of the injury was broken glass 1, stab wound 3, Arterial blood gas (ABG) taken 1, post explosive injuries 4, post RTA 1 & post gunshot injury 2 cases.

Introduction:-
Arterial pseudoneurysm and arteriovenous (AV) fistula might occur as a result of trauma in different parts of the body. These two entities can form independently of one another, but even though it is rare they also could be observed simultaneously. (4) The "classical" description of a traumatic AVM indicated that it was generally formed from single, direct communication between an artery and vein.
Clinical progress could get serious in this type of occurrences and because of the imminent clinical course early diagnosis and treatment are needed. But if symptoms occur, they vary from swelling to pain, even extending to heart failure due to high shunt volume. A thrill and bruit accompanying the AV shunt is characteristic, however, not always detectable. Many of the symptoms are reversible with surgery. (2) Surgical treatment is difficult and involves different methods according to location and feeding artery. (5) In this research, we present our approach to the diagnosis and treatment of a pseudoaneurysms, and arteriovenous fistula due to various type of injuries.
Pathophysiology:-An arteriovenous malformation consists of endothelial-lined communication between an artery and vein with no interposed capillary bed. The communication may be single (secondary to trauma, most commonly penetrating) or consist of multiple channels and spaces admixing the blood and forming a complex vascular structure (congenitalAVF).
There are two types of aneurysms: True arterial aneurysms involve all three layers of the artery wall (intima, media and adventitia), while False aneurysms Represent a collection of blood, held around the vessel by a wall of connective tissue. May occur following trauma or there may be a slow leak of blood which is confined by surrounding tissues, also can be arise following angiogram, angioplasty or at the join between a graft and the artery. Result in a slowly expanding blood-filled cavity, which will eventually rupture or lead to thrombosis.

Clinical presentation:-
The most common symptom of a traumatic AVM is pulsatile progressively enlarging mass and relate a history of a previous trauma. also most AVMs will have a palpable thrill even if a bruit is not present (2) Attention to traumatic arteriovenous communications has been concentrated around wartime experiences as penetrating shrapnels wounds have accounted for the majority of vascular wartime injuries (3) . We have identified 12 cases of such vascular lesions documented by Dupplex U/S & CTA from 11-2014 till 10-2016 (Table I).
The Superficial Femoral Artery was the most commonly involved feeder vessels. It is enlightening that the etiology of AVM was the majority of penetrating wounds leading to AVMs were a result of explosive in 4 of 11 cases, while the contusion injuries were usually automobile accidents.

Etiology
No. of cases Broken glass 1 Stab wound 3 ABG taken 1 Post explosive injuries 4 Post RTA 1 Post gunshot inj. 2 The summary of clinical finding in our 12 patients in (Table I) indicates that 4 were due to explosive injuries, 1 due to RTA, 3 following stab wounds, 1 due to broken glass injury, 2 following gunshot and 1 case iatrogenic following ABG taken during neonatal ICU admission. The symptoms began 1 day to 3 years following the trauma, with 4 being greater than 6 months. Swelling or the presence of a mass were the predominate symptoms in 10 patient, while intermittent claudication were described as the presenting complaint by 3 patients each.
1065   Although magnetic resonance angiography (MRA) is a noninvasive, radiation-free imaging modality, which can provide a high-resolution imaging, it was felt to be contraindicated in our patients due to the presence of residual metallic fragments from his previous injury. (8) In addition MRA was not available in our hospital to be done in other cases where metallic sharpenlls are not visible by x-ray ( Figure III Cases where post-traumatic arteriovenous fistula and pseudoaneurysm coexist are rare and these cases should get immediate treatment in the early phases when detected. Serious complications can frequently occur in such cases. These complication are repture, neuropathy, distal embolus, thrombosis (9) and delayed wound healing because of passage of blood back through arteriovenous fistula(AVF) (2) .Therefore, many cases should undergo surgery as soon as possible. Arteriovenous fistula affecting the cardiovascular system hemodynamically and damaging the structure of the vein. Besides, immediate surgical operation prevents the pressure upon the neighboring muscle and nerve tissues by the existing mass. Early surgery has many advantages; it is easier due to less sticking and vascularization, distal embolus and rupture can be avoided (Figures V & VI  Arterial pseudoaneurysm and arteriovenous (AV) fistula, these two entities can form independently of one another, but even though it is rare they also could be observed simultaneously. (4) In our research 5 out of 12 cases arterial pseudoaneurysm simultaneously with arteriovenous fistula.

Discharge in
Because of the fast progress of the post-traumatic pseudoaneurysm and arteriovenous fistula cases and the resultant serious complications, it is recommended that surgical operation should be done as soon as possible. This point of view is supported by the fact that no problem is encountered in the follow-up period after the operation. (10) In many cases, interventional therapy (stent implantation, coiling and thrombin injections) are possible options of treatment (11&12) but unfortunately are not available in our hospital. In our study, we performed different methods of vascular surgical interventions according to location and feeder vessels either by resection of the aneurysm and applied saphaneous interposition on the defective region in the artery and vein (which is preferred method) and less preferred surgical methods might be listed as ligation, synthetic graft use if autogenous venous graft was not sufficient. The critical issue in the surgical treatment is the resection of the vascular lesion with restoration of blood flow. The preferred method is the resection of the aneurysm and the primary repair of the pseudoaneurysm entrance. But, if the anastomosis cannot be performed without tension due to the loss of the tissues, then autogenous saphenous vein or synthetic graft can be used in vascular reconstruction. As for the arteriovenous fistula, artery and vein are separated from each other and the joint regions are repaired.
Complete surgical excision of the AVM remains the most successful therapy at this time. Ligation of the feeder vessels without excision of the AVM is not effective as it simply promotes preferential dilation of other collateral vessels reestablishing the blood flow pattern through the AVM. After being studied with CTA, the surgical plan is developed. (3) Exposure of the AVM can usually be obtained by the use of a variety of incisions according to site of AVM. Total excision of the lesion including as much length of abnormal afferent and efferent vessels as possible will reduce the danger of reformation of the AVM. So early detection of AVM can decrease the chance of segmental excision and graft repair. In our study 4 cases No. (5, 8, 9 & 12) graft repair was done and they were diagnosed late after more than 1 month. On the other hand, 1 case was detected early within 1 day where end to end anastomosis were done because when late diagnosis wall of the artery become part of wall of pseudoaneurysm. This leads to more resection to prevent pseudoaneurysm reformation and both ends distance become more wide which need graft repair. (Figure XIII) .

Conclusion:-
Posttraumatic pseudoaneurysms and arteriovenous fistulas are the vascular complication resulting from local traumas. for this reason, early angiography should be considered in penetrating injuries near major limb vessels, as the initial symptoms and signs of vascular injury may be minimal. (13) This procedure aims to avoid late sequelae which may need segmental excision of the injured vessels. (14) Also early intervention is needed to avoid rupture because of direct trauma or infection which make the repair difficult and increase risk of anastomotic failure because of infection more. Early surgery has many advantages; it is easier due to less sticking and vascularization, distal embolus and rupture can be avoided. Moreover, incidence of direct repair or end to end anastomosis are more applied in case of early rather than late diagnosis.