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Endovascular Repair of an Arteriovenous Fistula after Intervertebral Disk Surgery: Case Report
Endovascular Repair of an Arteriovenous Fistula after Intervertebral Disk Surgery: Case Report Scott Geraghty, MD, Janette D. Durham, MD, Jonathan M. Levy, MD, and Phillip S. Wolf, MD
Vascular injuries that complicate intervertebral disk surgery are rare. Despite being well-described, their clinical presentation is often overlooked. The authors report the delayed diagnosis of an arteriovenous fistula following disk surgery that led to advanced congestive failure and pulmonary hypertension mistakenly attributed to hepatic failure. Because endovascular repair offers complete resolution, accurate diagnosis is essential. The authors review the vascular injuries that can occur with disk surgery and the successful outcome with endovascular repair. J Vasc Interv Radiol 2009; 20:1235–1239
INTERVERTEBRAL disk surgery is a frequently performed and typically safe procedure. The anatomic relationship between the lumbar disks and the anterior abdominal vasculature provides a potential for life-threatening complications when the anterior longitudinal ligament is penetrated during a retroperitoneal surgical approach (1,2). Vascular injuries complicate lumbar disk surgery infrequently but diagnosis is often delayed for months after the occurrence, and often only after the patient develops cardiac failure secondary to a mature arteriovenous fistula (3). Diagnosis is aided by a high level of suspicion and a thorough knowledge of the type and location of the resulting vascular injuries. Surgical repair of these injuries is difficult and accompanied by significant morbidity and mortality (4). Now that covered stents are widely available, endovascular repair has replaced
From the University of Colorado at Denver, School of Medicine, Leprino Bldg, 12401 E 17th Ave, L954, PO Box 6510, Aurora, CO 80045 (S.G., J.D.D., P.S.W.); and Scottsdale Medical Imaging, Ltd, Scottsdale, Arizona (J.M.L.). Received October 28, 2008; final revision received June 2, 2009; accepted June 8, 2009. Address correspondence to J.D.D.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2009 DOI: 10.1016/j.jvir.2009.06.004
surgery as the primary approach to injuries with delayed presentation. Herein, we describe an iliac artery-tovein arteriovenous fistula following diskectomy and the debilitating clinical presentation that can result when the diagnosis is missed. The endovascular approach to such injuries is also reviewed. This report was exempt from institutional review board review.
CASE REPORT A 38-year-old man with a medical history significant for chronic back pain and multiple back surgeries underwent revision of an L5-S1 fusion. Previous surgeries had included two percutaneous diskectomies, at L4-5 and L5-S1 and a lumbar stabilization with rods, which were later removed. The most recent procedure improved his pain, but within 3 weeks he became markedly icteric and developed anasarca. Over the next several months, his weight rose from 167 to 287 pounds. Pulmonary arterial hypertension with a peak systolic pressure of 68 mm Hg was documented with echocardiography at another hospital. The serum bilirubin level was elevated to 4 mg/dL (68.4 mol/L). When an abdominal bruit was noted, an abdominal magnetic resonance (MR) image was obtained; findings were interpreted as negative. This image was not available for our review.
Sixteen months after his L5-S1 fusion revision, the patient presented to our facility. With aggressive diuretic therapy, his weight had decreased to 182 pounds. Physical examination revealed findings of congestive heart failure confirmed with chest radiography. Abdominal examination revealed hepatomegaly with massive ascites. The patient had no visible collateral channels at inspection of the abdominal wall and no stigmata of cirrhosis. A grade 5/6 continuous murmur over the lower abdomen and lumbar area was detected. An electrocardiogram was normal. On the basis of the patient’s symptoms and physical findings, a fistula was suspected. The following day, arteriography was performed with the patient under sedation. This helped confirm a fistulous connection between the right common iliac artery and the right common iliac vein near the inferior vena cava (Fig 1). The exact point of the fistula was difficult to visualize due to rapid flow into a massively dilated inferior vena cava despite multiple oblique views. A 12 ⫻ 70-mm Wallgraft Endoprosthesis (Boston Scientific MediTech, Natick, Massachusetts) was deployed in the right common iliac artery across the fistula. The fistula persistently filled. A second 12 ⫻ 30-mm Wallgraft Endoprosthesis was then placed inside the first to extend the graft proximally and correct a suspected inadequate seal at the proxi-
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Figure 2. Pelvic arteriogram obtained after deployment of two Wallgraft endoprostheses. The fistula persists in filling. Figure 1. Abdominal aortogram demonstrates a right common iliac artery-to-iliac vein fistula just upstream from a massively dilated inferior vena cava. The artery is dilated at the fistula site. There is minimal flow demonstrated distal to the fistula in the external iliac artery.
fistula was present at 1 month, and pulmonary artery pressure at repeat echocardiography had normalized. He has subsequently been followed up clinically for 4 years without further complication.
DISCUSSION mal end, a type I endoleak (Fig 2). When the fistula remained patent, an occlusion balloon was advanced in a retrograde direction through the stent-graft to control inflow and a distal injection performed through the sheath (Fig 3). This demonstrated a transgraft leak (type IV endoleak). A tapered 16 –12-mm GORE Excluder (Gore, Newark, Delaware) was deployed within the two Wallgrafts, spanning the common and external iliac artery. Subsequent pelvic arteriography showed minimal venous opacification (Fig 4). The day after the procedure, the abdominal murmur was no longer heard. One month after the procedure, the patient returned for follow-up. He had improved clinically with increased energy and consistent weight loss off diuretics. His bilirubin level decreased from 4.0 mg/dL (68 mol/L) to 2.2 mg/dL (38 mol/L). No clinical or arteriographic evidence of a persistent arteriovenous
Vascular complications of lumbar disk surgery are recognized but rare. The first case of documented injury following disk surgery involved an arteriovenous fistula between the right iliac artery and the inferior vena cava, reported in 1945 by Linton and White (5). The prevalence of vascular injuries arising from ventral perforation of the anterior longitudinal ligament has been reported to occur in 1–5 per 10,000 surgeries (0.02%– 0.06%) (1). Because vascular injuries may manifest remotely from the time of surgery, it is believed that the complication may be underreported. To understand the vascular anatomy important to vascular injury afterintravertebral disk surgery, Anda et al (6) reviewed the computed tomographic (CT) images of 50 patients referred with low back pain or sciatica. They found that at the L3-4 disk space,
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Figure 3. Right iliac arteriogram shows a retrograde occlusion balloon permitting retrograde filling of the fistula, which helps confirm a type IV endoleak.
in all but 4% of patients, the aorta and inferior vena cava ran parallel and anterior to the lumbar vertebrae separated from the anterior disk spaces by the anterior longitudinal ligament. At the L4-5 disk space, the aorta had bifurcated into right and left iliac arteries in 98% of patients. On the other hand, the common iliac veins had merged to form the inferior vena cava in all but 6% of patients at the same level. Some part of the inferior vena cava or left iliac vein was located posterior to the right iliac artery in nearly all patients and behind the left iliac artery in 44% of patients. At L5-S1, the iliac arteries and veins were found at the anterior lateral margins of the disk space and in a position at which clear separation was difficult. This anatomic clarification helps explain why injuries above the L4-5 disk space typically result in isolated injuries of the aorta or inferior vena cava. Both artery and vein are vulnerable at the L4-5 disk space and below. A recent literature review by Papadoulas et al (1) identified 98 patients with vascular injuries, including laceration (30%), arteriovenous fistula with or without pseudoaneurysm (67%), and pseudoaneurysm alone (3%). These complications may occur early or intra- or
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Figure 4. Aortogram shows that the addition of a GORE Excluder iliac limb inside the Wallgraft occludes flow through the fistula.
periprocedurally, often presenting as life-threatening hemorrhage. Hypotension, tachycardia, and abdominal distention are suggestive of the injury. Emergent laparotomy and vascular repair are indicated in clinical emergencies. The most frequent early injury is laceration of the left common iliac artery (2). Late complications include arteriovenous fistulas and, less commonly, pseudoaneurysms. Most injuries occur at the L4-5 disk space (73%), the remainder occur at L5-S1. Fistula formation can involve the right iliac artery to iliac vein (29%), left iliac artery to left iliac vein (26%), right iliac artery to inferior vena cava (22%), right iliac artery to left iliac vein (13%), and aorta to inferior vena cava (9%) (3). This variable presentation contributes to a delay in diagnosis. Almost 25% of arteriovenous fistulas are diagnosed 1 year or later after the initial surgery (3). Often, a fistula is suspected only after the development of high-output cardiac failure and its associated symptoms of tachycardia, systolic hypertension, dyspnea on exertion, orthopnea, cardiomegaly, pleural effusions, ascites with hepatomegaly, and lower extremity edema. Patients may describe symptoms of claudication in the leg supplied by the injured artery, often with swelling of the same extremity. The diagnosis is essentially con-
Geraghty et al firmed by finding a characteristic holosystolic murmur over the abdomen or lower back. Misdiagnosis is frequent, usually because of an incomplete physical examination. Other entities that are considered include deep venous thrombosis, endocarditis, and cardiac failure from other causes. Our patient was misdiagnosed as having hepatitis with subsequent development of cirrhosis and portal hypertension. In fact, the elevated liver function tests were likely secondary to chronic passive congestion due to the elevated venous pressure caused by the fistula. The pathophysiology of arteriovenous fistula involves several hemodynamic changes. Initially, there is increased blood flow in the arteries proximal to the fistula and decreased flow distal to the venous communication. If a major portion of the arterial flow is diverted into the venous circulation due to low peripheral resistance across the fistula, relative underfilling of the arterial tree results. The decrease in arterial pressure is sensed bybaroreceptors in the left ventricle, carotid sinuses, and aortic arch. These receptors then increase sympathetic outflow. A cascade of neurohormonal changes develops that seek to preserve blood volume, but this mechanism typically overcompensates. Ultimately there is an expansion of blood volume and a high-output state of cardiac failure, such as was found in our case. The treatment of arteriovenous fistulas has historically been surgical. Several techniques have been used, including fistula excision, with artery and vein repair done by means of eitherre-anastomosis or surgical graft placement. It may be difficult to access the injury because of enlargement of upstream arteries and numerous engorged veins, which pose a risk of massive hemorrhage if inadvertently incised. Difficult dissection also increases the risk of nerve injury. Patients who present with high-output cardiac failure may not tolerate general anesthesia and major vascular repair. Mortality from vascular injury following disk surgery has been variably reported to occur in 15%– 61% of patients (7). The highest mortality results from vascular lacerations that necessitate emergent repair. Repair of chronic fistulas is better tolerated, with mortality rates of 5%–10% (1). In 1995, Zajko et al (8) reported the first repair of an iliac to IVC arterio-
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venous fistula using a stent-graft after unsuccessful repair of an iatrogenic right iliac artery trocar injury sustained during laparoscopy. In 1996, three separate reports described closure of a left iliac artery to iliac vein fistula following diskectomy by using the CraggEndopro system (Boston Scientific, Watertown, MA) (9 –11). Our review of the literature identified 12 patients with vascular injuries afterdiskectomy that were initially repaired with endovascular stent-grafts (Table). These included seven arteriovenous fistulas, two arteriovenous fistulas with associated pseudoaneurysms, two pseudoaneurysms, and one laceration (9 –17). These cases all involved the iliac arteries, after surgery at the L4-5 and L5-S1 disk levels. All but one patient had a delayed presentation, most often with symptoms of heart failure. One patient, who was asymptomatic, was diagnosed incidentally during a physical examination. Coil embolization of the internal iliac artery to prevent retrograde filling of the fistula was performed in three cases. An array of homemade and manufactured devices was used. Only one case required subsequent surgery as a result of deployment malfunction. All other patients had documented closure of their fistulas with subsequent resolution of symptoms. Morbidity from the endovascular procedure was minimal. We add to the literature an additional case of endovascular repair of an iliac artery-to-iliac vein fistula, discovered 18 months after diskectomy, in a patient presenting with high-output cardiac failure. He had undergone multiple prior diskectomy procedures, an identified risk factor for vascular injury. The repair was technically successful and the patient has had no complications at follow-up. Internal iliac artery embolization was not performed. Initially, a Dacron graft failed to prevent flow through the fistula. This device was chosen in an attempt to avoid the need for a surgical cutdown. Placement of a larger polytetrafluoroethylene-covered graft, known to be less porous than Dacron, resolved what appeared to be a type 4 endoleak. Closure of the arteriotomy was still able to be accomplished manually without complication. In retrospect, preprocedure CT arteriography would have improved graft selection and a surgical team could have been
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Table Summary of Patients in the Current Literature Author and Year
Patient Age (y)/ Sex
Disk Level
Injury
Presentation after Surgery
Device
Results/Complications
McCarter et al (9), 1996 Allgayer et al (10), 1996 Brunkwall et al (11), 1996
64/M
L4-5
L CIA—L CIV fistula
4 y with CHF, claudication
Cragg Endopro System
Resolution/none
55/M
L5-S1
L CIA—L CIV fistula
16 mo with CHF, AM
Cragg Endopro System
Resolution/none
58/F
L5-S1
L CIA—L CIV fistula
12 mo with arrythmia, AM
Resolution/none
Lee et al (12), 2000
23/M
L5-S1
R CIA—R CIV fistula
12 mo with PAM, AM
Hong et al (13), 2000
24/F
L4-5
R CIA PA
Ventura et al (14), 2002 Hart et al (15), 2003
51/F
L5-S1
R CIA—R CIV fistula
AneuRX (Medtronics, Minneapolis, Minnesota)
Resolution/none
41/F
R CIA—R CIV fistula
5 d with bleeding, PA ⬍1 wk with CHF, AM, hemoptysis 8 y with AM
Handmade expanded polytetrafluoroethylene (Gore, Flagstaff, Arizona)covered Gianturco Z stent (Cook Europe, Bagsvaerd, Denmark) Homemade Z stent covered with polytetrafluoroethylene (Cook) with embolization of R IIA Passager stent-graft (Boston Scientific)
Resolution/none
Kwon et al (16), 2003
35/M
L CIA PA
6 mo
Covered Wallstent (Boston Scientific, Galway, Ireland) and coil embolization of R IIA Grafts—type not specified
23/M
R CIA—R CIV fistula L CIA—L CIV and PA R CIA—R CIV and PA
23 mo
Jostent (Jomed, Helsingborg, Sweden) and coil embolization of IIA
Resolution/none
27/M 17/M
Bierdrager et al (4), 2004
57/F
L4-5
R CIA laceration
Resolution/none
Resolution/none
Resolution (n ⫽ 3), surgical conversion for deployment failure (n ⫽ 1)
2 mo 2 wk Findings not provided 1 h with hypotension
Note.—AM ⫽ abdominal murmur, CHF ⫽ congestive heart failure, CIA ⫽ common iliac artery, CIV ⫽ common iliac vein, PA ⫽ pseudoaneurysm, PAM ⫽ pulsating abdominal mass, R IIA ⫽ right internal iliac artery.
consulted for assistance with access if needed. Larger series of all-cause arteriovenous fistulas repaired with stentgrafts emphasize the high success rate and low morbidity and mortality related to this approach (17). These results suggest that endovascular repair should be considered the first-line therapy for any such injury when the clinical presentation permits preprocedural evaluation with imaging and planning of appropriate repair. This approach may
also be appropriate for some early injuries if the patient’s clinical status can be stabilized. Endovascular repair is associated with decreased blood loss, reduced requirement for anesthesia, and a limited need for extensive dissection in patients who often present with severe debilitation from high-output failure. Current stent-graft technology permits a percutaneous approach, avoiding even the small morbidity associated with surgical femoral exposure. The challenge with these injuries re-
mains the identification of the problem early enough to avoid cardiac, renal, and other end organ damage. When there is suspicion of ventral perforation into the retroperitoneal space at surgery that is not apparent clinically, emergent imaging evaluation should be pursued. Negative findings immediately after surgery when perforation is suspected do not exclude vascular injury, and follow-up for development of the late manifestations of an injury is necessary. In addition, understanding the clinical
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presentation of these injuries and listening for the classic abdominal/lumbar bruit will ensure that patients with highoutput heart failure are correctly identified. References 1. Papadoulas S, Konstantinou D, Kourea HP, Kritikos N, Haftouras N, Tsolakis JA. Vascular injury complicating lumbar disc surgery: a systematic review. Eur J Vasc Endovasc Surg 2002; 24:189–195. 2. Raptis S, Quigley F, Barker S. Vascular complications of elective lower lumbar disc surgery. Aust N Z J Surg 1994; 64: 216 –219. 3. Jarstfer BS, Rich NM. The challenge of arteriovenous fistula formation following disk surgery: a collective review. J Trauma 1976; 16:726 –733. 4. Bierdrager E, van Rooij WJ, Sluzewski M. Emergency stenting to control massive bleeding of injured iliac artery following lumbar disk surgery. Neuroradiology 2004; 46:404 – 406. 5. Linton RR, White PD. Arteriovenous fistula between the right common iliac artery and the inferior vena cava: report of a case following operation for a ruptured intervertebral disc. Arch Surg 1945; 50:6 –13.
Geraghty et al
6. Anda S, Aakhus S, Skaanes KO, Sande E, Schrader H. Anterior perforations in lumbar discectomies: a report of four cases of vascular complications and a CT study of the prevertebral lumbar anatomy. Spine 1991; 16:54 – 60. 7. Goodkin R, Laska LL. Vascular and visceral injuries associated with lumbar disc surgery: medicolegal implications. Surg Neurol 1998; 49:358 –372. 8. Zajko AB, Little AF, Steed DL, Curtiss EI. Endovascular stent-graft repair of common iliac artery-to-inferior vena cava fistula. J Vasc Interv Radiol 1995; 6:803– 806. 9. McCarter DH, Johnstone RD, McInnes GC, Reid DB, Pollock JG, Reid AW. Iliac arteriovenous fistula following lumbar disc surgery treated by percutaneous endoluminal stent grafting. Br J Surg 1996; 83:796 –797. 10. Allgayer B, Theiss W, Naundorf M. Percutaneous closure of an arteriovenous iliac fistula with a Cragg Endoluminal graft. AJR Am J Roentgenol 1966; 166:673– 674. 11. Brunkwall J, Lindblad B, Ivancev K, Emtersjo G, Risberg B. Iatrogenic AVfistula treated by a graft-covered selfexpandable stent. Eur J Vasc Endovasc Surg 1996; 12:243–245.
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12. Lee KH, Park JH, Chung JW, Han JK, Shin SJ, Kang HS. Vascular complications in lumbar spinal surgery: percutaneous endovascular treatment. Cardiovasc Intervent Radiol 2000; 23:65– 69. 13. Hong SJ, Oh JH, Yoon Y. Percutaneous endovascular stent-graft for iliac pseudoaneurysm following lumbar discectomy. Cardiovasc Intervent Radiol 2000; 23: 475– 477. 14. Ventura M, Rivellini C, Saracino G, Mastromarino A, Spartera C, Zannetti S. Endovascular treatment of a postlaminectomy arteriovenous fistula: a case report. J Cardiovasc Surg 2002; 43:523–526. 15. Hart JP, Wallis F, Kenny B, O’Sullivan B, Burke PE, Grace PA. Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery. J Vasc Surg 2003; 37:1091–1093. 16. Kwon T, Sung K, Cho Y, et al. Large vessel injury following operation for a herniated lumbar disc. Ann Vasc Surg 2003; 17:438 – 444. 17. Parodi JC, Schonholz C, Ferreira LM, Bergan J. Endovascular stent-graft treatment of traumatic arterial lesions. Ann Vasc Surg 1999; 13:121–129.
Vascular injuries that complicate intervertebral disk surgery are rare. Despite being well-described, their clinical presentation is often overlooked. The authors report the delayed diagnosis of an arteriovenous fistula following disk surgery that led to advanced congestive failure and pulmonary hypertension mistakenly attributed to hepatic failure. Because endovascular repair offers complete resolution, accurate diagnosis is essential. The authors review the vascular injuries that can occur with disk surgery and the successful outcome with endovascular repair. J Vasc Interv Radiol 2009; 20:1235–1239
INTERVERTEBRAL disk surgery is a frequently performed and typically safe procedure. The anatomic relationship between the lumbar disks and the anterior abdominal vasculature provides a potential for life-threatening complications when the anterior longitudinal ligament is penetrated during a retroperitoneal surgical approach (1,2). Vascular injuries complicate lumbar disk surgery infrequently but diagnosis is often delayed for months after the occurrence, and often only after the patient develops cardiac failure secondary to a mature arteriovenous fistula (3). Diagnosis is aided by a high level of suspicion and a thorough knowledge of the type and location of the resulting vascular injuries. Surgical repair of these injuries is difficult and accompanied by significant morbidity and mortality (4). Now that covered stents are widely available, endovascular repair has replaced
From the University of Colorado at Denver, School of Medicine, Leprino Bldg, 12401 E 17th Ave, L954, PO Box 6510, Aurora, CO 80045 (S.G., J.D.D., P.S.W.); and Scottsdale Medical Imaging, Ltd, Scottsdale, Arizona (J.M.L.). Received October 28, 2008; final revision received June 2, 2009; accepted June 8, 2009. Address correspondence to J.D.D.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2009 DOI: 10.1016/j.jvir.2009.06.004
surgery as the primary approach to injuries with delayed presentation. Herein, we describe an iliac artery-tovein arteriovenous fistula following diskectomy and the debilitating clinical presentation that can result when the diagnosis is missed. The endovascular approach to such injuries is also reviewed. This report was exempt from institutional review board review.
CASE REPORT A 38-year-old man with a medical history significant for chronic back pain and multiple back surgeries underwent revision of an L5-S1 fusion. Previous surgeries had included two percutaneous diskectomies, at L4-5 and L5-S1 and a lumbar stabilization with rods, which were later removed. The most recent procedure improved his pain, but within 3 weeks he became markedly icteric and developed anasarca. Over the next several months, his weight rose from 167 to 287 pounds. Pulmonary arterial hypertension with a peak systolic pressure of 68 mm Hg was documented with echocardiography at another hospital. The serum bilirubin level was elevated to 4 mg/dL (68.4 mol/L). When an abdominal bruit was noted, an abdominal magnetic resonance (MR) image was obtained; findings were interpreted as negative. This image was not available for our review.
Sixteen months after his L5-S1 fusion revision, the patient presented to our facility. With aggressive diuretic therapy, his weight had decreased to 182 pounds. Physical examination revealed findings of congestive heart failure confirmed with chest radiography. Abdominal examination revealed hepatomegaly with massive ascites. The patient had no visible collateral channels at inspection of the abdominal wall and no stigmata of cirrhosis. A grade 5/6 continuous murmur over the lower abdomen and lumbar area was detected. An electrocardiogram was normal. On the basis of the patient’s symptoms and physical findings, a fistula was suspected. The following day, arteriography was performed with the patient under sedation. This helped confirm a fistulous connection between the right common iliac artery and the right common iliac vein near the inferior vena cava (Fig 1). The exact point of the fistula was difficult to visualize due to rapid flow into a massively dilated inferior vena cava despite multiple oblique views. A 12 ⫻ 70-mm Wallgraft Endoprosthesis (Boston Scientific MediTech, Natick, Massachusetts) was deployed in the right common iliac artery across the fistula. The fistula persistently filled. A second 12 ⫻ 30-mm Wallgraft Endoprosthesis was then placed inside the first to extend the graft proximally and correct a suspected inadequate seal at the proxi-
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Figure 2. Pelvic arteriogram obtained after deployment of two Wallgraft endoprostheses. The fistula persists in filling. Figure 1. Abdominal aortogram demonstrates a right common iliac artery-to-iliac vein fistula just upstream from a massively dilated inferior vena cava. The artery is dilated at the fistula site. There is minimal flow demonstrated distal to the fistula in the external iliac artery.
fistula was present at 1 month, and pulmonary artery pressure at repeat echocardiography had normalized. He has subsequently been followed up clinically for 4 years without further complication.
DISCUSSION mal end, a type I endoleak (Fig 2). When the fistula remained patent, an occlusion balloon was advanced in a retrograde direction through the stent-graft to control inflow and a distal injection performed through the sheath (Fig 3). This demonstrated a transgraft leak (type IV endoleak). A tapered 16 –12-mm GORE Excluder (Gore, Newark, Delaware) was deployed within the two Wallgrafts, spanning the common and external iliac artery. Subsequent pelvic arteriography showed minimal venous opacification (Fig 4). The day after the procedure, the abdominal murmur was no longer heard. One month after the procedure, the patient returned for follow-up. He had improved clinically with increased energy and consistent weight loss off diuretics. His bilirubin level decreased from 4.0 mg/dL (68 mol/L) to 2.2 mg/dL (38 mol/L). No clinical or arteriographic evidence of a persistent arteriovenous
Vascular complications of lumbar disk surgery are recognized but rare. The first case of documented injury following disk surgery involved an arteriovenous fistula between the right iliac artery and the inferior vena cava, reported in 1945 by Linton and White (5). The prevalence of vascular injuries arising from ventral perforation of the anterior longitudinal ligament has been reported to occur in 1–5 per 10,000 surgeries (0.02%– 0.06%) (1). Because vascular injuries may manifest remotely from the time of surgery, it is believed that the complication may be underreported. To understand the vascular anatomy important to vascular injury afterintravertebral disk surgery, Anda et al (6) reviewed the computed tomographic (CT) images of 50 patients referred with low back pain or sciatica. They found that at the L3-4 disk space,
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Figure 3. Right iliac arteriogram shows a retrograde occlusion balloon permitting retrograde filling of the fistula, which helps confirm a type IV endoleak.
in all but 4% of patients, the aorta and inferior vena cava ran parallel and anterior to the lumbar vertebrae separated from the anterior disk spaces by the anterior longitudinal ligament. At the L4-5 disk space, the aorta had bifurcated into right and left iliac arteries in 98% of patients. On the other hand, the common iliac veins had merged to form the inferior vena cava in all but 6% of patients at the same level. Some part of the inferior vena cava or left iliac vein was located posterior to the right iliac artery in nearly all patients and behind the left iliac artery in 44% of patients. At L5-S1, the iliac arteries and veins were found at the anterior lateral margins of the disk space and in a position at which clear separation was difficult. This anatomic clarification helps explain why injuries above the L4-5 disk space typically result in isolated injuries of the aorta or inferior vena cava. Both artery and vein are vulnerable at the L4-5 disk space and below. A recent literature review by Papadoulas et al (1) identified 98 patients with vascular injuries, including laceration (30%), arteriovenous fistula with or without pseudoaneurysm (67%), and pseudoaneurysm alone (3%). These complications may occur early or intra- or
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Figure 4. Aortogram shows that the addition of a GORE Excluder iliac limb inside the Wallgraft occludes flow through the fistula.
periprocedurally, often presenting as life-threatening hemorrhage. Hypotension, tachycardia, and abdominal distention are suggestive of the injury. Emergent laparotomy and vascular repair are indicated in clinical emergencies. The most frequent early injury is laceration of the left common iliac artery (2). Late complications include arteriovenous fistulas and, less commonly, pseudoaneurysms. Most injuries occur at the L4-5 disk space (73%), the remainder occur at L5-S1. Fistula formation can involve the right iliac artery to iliac vein (29%), left iliac artery to left iliac vein (26%), right iliac artery to inferior vena cava (22%), right iliac artery to left iliac vein (13%), and aorta to inferior vena cava (9%) (3). This variable presentation contributes to a delay in diagnosis. Almost 25% of arteriovenous fistulas are diagnosed 1 year or later after the initial surgery (3). Often, a fistula is suspected only after the development of high-output cardiac failure and its associated symptoms of tachycardia, systolic hypertension, dyspnea on exertion, orthopnea, cardiomegaly, pleural effusions, ascites with hepatomegaly, and lower extremity edema. Patients may describe symptoms of claudication in the leg supplied by the injured artery, often with swelling of the same extremity. The diagnosis is essentially con-
Geraghty et al firmed by finding a characteristic holosystolic murmur over the abdomen or lower back. Misdiagnosis is frequent, usually because of an incomplete physical examination. Other entities that are considered include deep venous thrombosis, endocarditis, and cardiac failure from other causes. Our patient was misdiagnosed as having hepatitis with subsequent development of cirrhosis and portal hypertension. In fact, the elevated liver function tests were likely secondary to chronic passive congestion due to the elevated venous pressure caused by the fistula. The pathophysiology of arteriovenous fistula involves several hemodynamic changes. Initially, there is increased blood flow in the arteries proximal to the fistula and decreased flow distal to the venous communication. If a major portion of the arterial flow is diverted into the venous circulation due to low peripheral resistance across the fistula, relative underfilling of the arterial tree results. The decrease in arterial pressure is sensed bybaroreceptors in the left ventricle, carotid sinuses, and aortic arch. These receptors then increase sympathetic outflow. A cascade of neurohormonal changes develops that seek to preserve blood volume, but this mechanism typically overcompensates. Ultimately there is an expansion of blood volume and a high-output state of cardiac failure, such as was found in our case. The treatment of arteriovenous fistulas has historically been surgical. Several techniques have been used, including fistula excision, with artery and vein repair done by means of eitherre-anastomosis or surgical graft placement. It may be difficult to access the injury because of enlargement of upstream arteries and numerous engorged veins, which pose a risk of massive hemorrhage if inadvertently incised. Difficult dissection also increases the risk of nerve injury. Patients who present with high-output cardiac failure may not tolerate general anesthesia and major vascular repair. Mortality from vascular injury following disk surgery has been variably reported to occur in 15%– 61% of patients (7). The highest mortality results from vascular lacerations that necessitate emergent repair. Repair of chronic fistulas is better tolerated, with mortality rates of 5%–10% (1). In 1995, Zajko et al (8) reported the first repair of an iliac to IVC arterio-
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venous fistula using a stent-graft after unsuccessful repair of an iatrogenic right iliac artery trocar injury sustained during laparoscopy. In 1996, three separate reports described closure of a left iliac artery to iliac vein fistula following diskectomy by using the CraggEndopro system (Boston Scientific, Watertown, MA) (9 –11). Our review of the literature identified 12 patients with vascular injuries afterdiskectomy that were initially repaired with endovascular stent-grafts (Table). These included seven arteriovenous fistulas, two arteriovenous fistulas with associated pseudoaneurysms, two pseudoaneurysms, and one laceration (9 –17). These cases all involved the iliac arteries, after surgery at the L4-5 and L5-S1 disk levels. All but one patient had a delayed presentation, most often with symptoms of heart failure. One patient, who was asymptomatic, was diagnosed incidentally during a physical examination. Coil embolization of the internal iliac artery to prevent retrograde filling of the fistula was performed in three cases. An array of homemade and manufactured devices was used. Only one case required subsequent surgery as a result of deployment malfunction. All other patients had documented closure of their fistulas with subsequent resolution of symptoms. Morbidity from the endovascular procedure was minimal. We add to the literature an additional case of endovascular repair of an iliac artery-to-iliac vein fistula, discovered 18 months after diskectomy, in a patient presenting with high-output cardiac failure. He had undergone multiple prior diskectomy procedures, an identified risk factor for vascular injury. The repair was technically successful and the patient has had no complications at follow-up. Internal iliac artery embolization was not performed. Initially, a Dacron graft failed to prevent flow through the fistula. This device was chosen in an attempt to avoid the need for a surgical cutdown. Placement of a larger polytetrafluoroethylene-covered graft, known to be less porous than Dacron, resolved what appeared to be a type 4 endoleak. Closure of the arteriotomy was still able to be accomplished manually without complication. In retrospect, preprocedure CT arteriography would have improved graft selection and a surgical team could have been
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Endovascular Repair of an AVF Following Disk Surgery
JVIR
Table Summary of Patients in the Current Literature Author and Year
Patient Age (y)/ Sex
Disk Level
Injury
Presentation after Surgery
Device
Results/Complications
McCarter et al (9), 1996 Allgayer et al (10), 1996 Brunkwall et al (11), 1996
64/M
L4-5
L CIA—L CIV fistula
4 y with CHF, claudication
Cragg Endopro System
Resolution/none
55/M
L5-S1
L CIA—L CIV fistula
16 mo with CHF, AM
Cragg Endopro System
Resolution/none
58/F
L5-S1
L CIA—L CIV fistula
12 mo with arrythmia, AM
Resolution/none
Lee et al (12), 2000
23/M
L5-S1
R CIA—R CIV fistula
12 mo with PAM, AM
Hong et al (13), 2000
24/F
L4-5
R CIA PA
Ventura et al (14), 2002 Hart et al (15), 2003
51/F
L5-S1
R CIA—R CIV fistula
AneuRX (Medtronics, Minneapolis, Minnesota)
Resolution/none
41/F
R CIA—R CIV fistula
5 d with bleeding, PA ⬍1 wk with CHF, AM, hemoptysis 8 y with AM
Handmade expanded polytetrafluoroethylene (Gore, Flagstaff, Arizona)covered Gianturco Z stent (Cook Europe, Bagsvaerd, Denmark) Homemade Z stent covered with polytetrafluoroethylene (Cook) with embolization of R IIA Passager stent-graft (Boston Scientific)
Resolution/none
Kwon et al (16), 2003
35/M
L CIA PA
6 mo
Covered Wallstent (Boston Scientific, Galway, Ireland) and coil embolization of R IIA Grafts—type not specified
23/M
R CIA—R CIV fistula L CIA—L CIV and PA R CIA—R CIV and PA
23 mo
Jostent (Jomed, Helsingborg, Sweden) and coil embolization of IIA
Resolution/none
27/M 17/M
Bierdrager et al (4), 2004
57/F
L4-5
R CIA laceration
Resolution/none
Resolution/none
Resolution (n ⫽ 3), surgical conversion for deployment failure (n ⫽ 1)
2 mo 2 wk Findings not provided 1 h with hypotension
Note.—AM ⫽ abdominal murmur, CHF ⫽ congestive heart failure, CIA ⫽ common iliac artery, CIV ⫽ common iliac vein, PA ⫽ pseudoaneurysm, PAM ⫽ pulsating abdominal mass, R IIA ⫽ right internal iliac artery.
consulted for assistance with access if needed. Larger series of all-cause arteriovenous fistulas repaired with stentgrafts emphasize the high success rate and low morbidity and mortality related to this approach (17). These results suggest that endovascular repair should be considered the first-line therapy for any such injury when the clinical presentation permits preprocedural evaluation with imaging and planning of appropriate repair. This approach may
also be appropriate for some early injuries if the patient’s clinical status can be stabilized. Endovascular repair is associated with decreased blood loss, reduced requirement for anesthesia, and a limited need for extensive dissection in patients who often present with severe debilitation from high-output failure. Current stent-graft technology permits a percutaneous approach, avoiding even the small morbidity associated with surgical femoral exposure. The challenge with these injuries re-
mains the identification of the problem early enough to avoid cardiac, renal, and other end organ damage. When there is suspicion of ventral perforation into the retroperitoneal space at surgery that is not apparent clinically, emergent imaging evaluation should be pursued. Negative findings immediately after surgery when perforation is suspected do not exclude vascular injury, and follow-up for development of the late manifestations of an injury is necessary. In addition, understanding the clinical
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Number 9
presentation of these injuries and listening for the classic abdominal/lumbar bruit will ensure that patients with highoutput heart failure are correctly identified. References 1. Papadoulas S, Konstantinou D, Kourea HP, Kritikos N, Haftouras N, Tsolakis JA. Vascular injury complicating lumbar disc surgery: a systematic review. Eur J Vasc Endovasc Surg 2002; 24:189–195. 2. Raptis S, Quigley F, Barker S. Vascular complications of elective lower lumbar disc surgery. Aust N Z J Surg 1994; 64: 216 –219. 3. Jarstfer BS, Rich NM. The challenge of arteriovenous fistula formation following disk surgery: a collective review. J Trauma 1976; 16:726 –733. 4. Bierdrager E, van Rooij WJ, Sluzewski M. Emergency stenting to control massive bleeding of injured iliac artery following lumbar disk surgery. Neuroradiology 2004; 46:404 – 406. 5. Linton RR, White PD. Arteriovenous fistula between the right common iliac artery and the inferior vena cava: report of a case following operation for a ruptured intervertebral disc. Arch Surg 1945; 50:6 –13.
Geraghty et al
6. Anda S, Aakhus S, Skaanes KO, Sande E, Schrader H. Anterior perforations in lumbar discectomies: a report of four cases of vascular complications and a CT study of the prevertebral lumbar anatomy. Spine 1991; 16:54 – 60. 7. Goodkin R, Laska LL. Vascular and visceral injuries associated with lumbar disc surgery: medicolegal implications. Surg Neurol 1998; 49:358 –372. 8. Zajko AB, Little AF, Steed DL, Curtiss EI. Endovascular stent-graft repair of common iliac artery-to-inferior vena cava fistula. J Vasc Interv Radiol 1995; 6:803– 806. 9. McCarter DH, Johnstone RD, McInnes GC, Reid DB, Pollock JG, Reid AW. Iliac arteriovenous fistula following lumbar disc surgery treated by percutaneous endoluminal stent grafting. Br J Surg 1996; 83:796 –797. 10. Allgayer B, Theiss W, Naundorf M. Percutaneous closure of an arteriovenous iliac fistula with a Cragg Endoluminal graft. AJR Am J Roentgenol 1966; 166:673– 674. 11. Brunkwall J, Lindblad B, Ivancev K, Emtersjo G, Risberg B. Iatrogenic AVfistula treated by a graft-covered selfexpandable stent. Eur J Vasc Endovasc Surg 1996; 12:243–245.
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12. Lee KH, Park JH, Chung JW, Han JK, Shin SJ, Kang HS. Vascular complications in lumbar spinal surgery: percutaneous endovascular treatment. Cardiovasc Intervent Radiol 2000; 23:65– 69. 13. Hong SJ, Oh JH, Yoon Y. Percutaneous endovascular stent-graft for iliac pseudoaneurysm following lumbar discectomy. Cardiovasc Intervent Radiol 2000; 23: 475– 477. 14. Ventura M, Rivellini C, Saracino G, Mastromarino A, Spartera C, Zannetti S. Endovascular treatment of a postlaminectomy arteriovenous fistula: a case report. J Cardiovasc Surg 2002; 43:523–526. 15. Hart JP, Wallis F, Kenny B, O’Sullivan B, Burke PE, Grace PA. Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery. J Vasc Surg 2003; 37:1091–1093. 16. Kwon T, Sung K, Cho Y, et al. Large vessel injury following operation for a herniated lumbar disc. Ann Vasc Surg 2003; 17:438 – 444. 17. Parodi JC, Schonholz C, Ferreira LM, Bergan J. Endovascular stent-graft treatment of traumatic arterial lesions. Ann Vasc Surg 1999; 13:121–129.