The Elephant Trunk Procedure for Aortic Aneurysm Repair: An Illustrated Guide to Surgical Technique With CT Correlation

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1 ardiopulmonary Imaging Pictorial Essay Johnson et al. Elephant Trunk Procedure for ortic neurysm Repair ardiopulmonary Imaging Pictorial Essay Pamela T. Johnson 1 Frank M. orl 1 James H. lack 2 Elliot K. Fishman 1 Johnson PT, orl FM, lack JH, Fishman EK Keywords: aorta, aortic graft, T, elephant trunk procedure, surgical repair DOI: /JR Received December 21, 2010; accepted after revision June 8, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, 601 N aroline St, Rm 3140D, altimore, MD ddress correspondence to P. T. Johnson (Pjohnso5@jhmi.edu). 2 Department of Vascular Surgery, Johns Hopkins Hospital, altimore, MD. ME This article is available for ME credit. See for more information. WE This is a Web exclusive article. JR 2011; 197:W1052 W X/11/1976 W1052 merican Roentgen Ray Society The Elephant Trunk Procedure for ortic neurysm Repair: n Illustrated Guide to Surgical Technique With T orrelation OJETIVE. The purpose of this article is to provide a comprehensive overview of a relatively new surgical aortic procedure, the elephant trunk technique. In conjunction with information from the literature, a series of illustrations provide a detailed description of the surgical procedure and postoperative appearance with T correlation. ONLUSION. This article explains the rationale behind a staged thoracic aortic surgery, describes and illustrates the surgical technique used to perform the elephant trunk procedure and the normal postoperative imaging appearance, and discusses potential complications specific to the elephant trunk procedure. T he arrival of the millennium coincided with the 50th anniversary of the first successful aortic aneurysm surgical repair [1]. efore that initial operation using a cadaver graft in 1951, techniques for treating aortic aneurysms included aortic ligation and wrapping aneurysms in cellophane, the latter with variable success [1]: In December 1948, lbert Einstein was operated on by Rudolph Nissen at the rooklyn Jewish Hospital in New York. ecause the aneurysm was large and mobilization of the anterior aorta was considered too dangerous, Nissen was able to wrap only the anterior two-thirds of the aneurysm with a piece of yellow cellophane. Einstein lived 6 years with the cellophane wrap before his aneurysm ruptured. The use of a cadaver graft was the first step in making aneurysm repair a reality. Notable milestones that followed include Vorhees 1952 invention of synthetic prostheses to expedite repair of abdominal aneurysms. dvances in surgical technology, such as cardiopulmonary bypass, allowed repair of ascending aortic aneurysms and aortic arch aneurysms. However, the question of how to treat extensive aneurysmal change including a combined aortic arch and descending thoracic aorta aneurysm or a thoracoabdominal aortic aneurysm remained unanswered until the mid 1980s. The elephant trunk technique was devised to address combined aneurysms, wherein the arch repair is facilitated by sternotomy and a second staged procedure is performed via left thoracotomy for the descending or thoraco abdominal aorta [2, 3]. lthough endovascular techniques remain the preferred modality in most patients for the treatment of a typical isolated descending thoracic aortic aneurysm, extensive aneurysms are more commonly addressed with open surgery. Future prospects for endovascular devices with side branches to preserve the supraaortic branches may change this paradigm [1]. The purpose of this article is to provide a comprehensive overview of a relatively new surgical aortic procedure, the elephant trunk technique. The elephant trunk was devised in 1983 by Hans orst and colleagues [4] with the goal of reducing complications during repair of extensive aortic aneurysms that is, aneurysms involving the ascending and descending thoracic aorta by performing a staged procedure [2, 3]. Typically, the ascending thoracic aorta is repaired first (Fig. 1), and a free-floating graft (the elephant trunk ) extends from the aortic arch into the descending thoracic aorta (Fig. 2) to be used for the subsequent repair of the descending thoracic aorta. For patients with degenerative aneurysms of the descending thoracic aorta, the second stage may also be accomplished with an endovascular stent-graft using the free-floating proximal graft as the proximal fixation zone. In conjunction with background and surgical W1052 JR:197, December 2011

2 Elephant Trunk Procedure for ortic neurysm Repair results described in the literature, a series of illustrations provide a detailed description of the actual surgical procedure and the postoperative appearance. History fter the original procedure was described by orst et al. [4] in 1983, the elephant trunk technique was improved by rawford et al. [5] and Svensson [6]. Their modifications included placement of the graft in the descending aorta, as opposed to the ascending aorta, and a reduction in the length of the free end of the graft [3]. Variations in the surgery that subsequently evolved include the reversed elephant trunk and bidirectional elephant trunk procedures [7, 8]. dvantages The elephant trunk technique arose out of several challenges associated with a single repair and staged repairs. With respect to attempting repair of the entire thoracic aorta during one procedure, it is not feasible to expose the ascending and descending thoracic aorta with a single incision. ccordingly, staged repair has become the mainstay. However, the early procedures carried considerable risk of hemorrhage during stage II redissection at the anastomosis owing to postoperative adhesions in the region of the aortic arch [2, 8]. Surgical dissection in this region commonly resulted in pulmonary artery or aortic laceration [9]. n advantage of the elephant trunk procedure is that placement of the elephant trunk during the first procedure provides a graft that is accessible downstream from the aortic arch, so surgical dissection can be performed in unaltered tissue planes of the descending thoracic aorta. second advantage is that placement of the elephant trunk during the first surgery obviates descending aorta cross-clamping during the second stage [3, 8]; instead, the elephant trunk graft is delivered from the aortic lumen and is clamped directly. Indications The elephant trunk technique is used when extensive thoracic aortic disease necessitates a two-stage repair: repair of the ascending aorta and aortic arch followed by repair of the descending aorta with or without repair of the abdominal aorta [2, 3]. The specific pathologic indications reported in the literature include aneurysm (atherosclerotic, postdissection, inflammatory) and, infrequently, acute dissection [2]. The elephant trunk technique is usually performed as an elective repair (91 94%) [2, 3, 10]. Procedure: Stage I The initial surgery (Fig. 1), stage I, is conducted with cardiopulmonary bypass and profound hypothermia to minimize neurologic complications [10]. To conceptualize the normal postoperative appearance of the elephant trunk, it is important to understand exactly what the technique entails. Defined as free-floating extension of a vascular aortic arch prosthesis into the proximal descending aorta [2], an elephant trunk involves a unique manipulation of a standard polyester fiber (Dacron, DuPont) graft as opposed to a specialized graft. The elephant trunk procedure is simply described as follows: The surgeon manually invaginates the graft and sutures the folded end of the graft to the aortic arch, distal to the great vessels. The proximal portion of the graft is then retracted into the aortic arch and sutured proximally, with orifices created for the branch vessels. The distal portion of the graft, the free end, remains draped in the descending thoracic aorta, oriented antegrade, awaiting the second-stage surgery to repair the descending thoracic aorta (Figs. 2 and 3). Intersurgical Interval The interval between the first and second surgeries has varied: For example, a mean intervals of 147 days or 4.9 months (range, 6 days 60.7 months) [10], 341 days ( days) [2], and 450 days or 14.7 months (1 hour 92 months) [8] have been reported. t our institution, we aim for staged reconstruction within 2 3 months after the first surgery; however, if the distal arch tissues are very attenuated from degenerative change, then the second stage may be performed during the same hospital admission. Procedure: Stage II In planning the second surgery, stage II, an adequate recovery time after the first surgery is balanced with the risk of descending thoracic aortic rupture during the intersurgical interval [11]. The variables that dictate the timing of stage II include the patient s medical condition, including comorbidities, and specific requirements with respect to the pathologic descending aorta. dilated descending aorta must reach a specific caliber before definitive repair can be performed. For example, thresholds include 6 cm for atherosclerotic aneurysm of the descending aorta, 5 cm for the descending aorta in patients with Marfan syndrome, and 5 cm for the abdominal aorta [2]. The descending aorta is then replaced with a graft that incorporates the elephant trunk or is repaired with stents (Figs. 4 and 5). Metallic clips on the end of the Dacron graft help facilitate cannulation of the dangling Dacron graft and overlapping the stent-graft within [10] (Fig. 5). Variants The descending aorta can be repaired first using a reverse elephant trunk technique [7, 8]. This sequence is selected when the descending aorta abnormality carries a higher risk of mortality than the ascending aorta abnormality, such as a contained rupture of the descending thoracic aorta. The inverted graft is placed in the descending thoracic aorta and is sutured distally and retracted during the arch repair. The advantages of the reversed elephant trunk technique include better access to the arch vessels because the anastomosis is distal to the arch and a shortened circulatory arrest period during subsequent aortic arch repair [7]. In patients with disease that involves the thoracic and abdominal aorta, the descending aorta can be repaired initially and bidirectional elephant trunk prostheses can be placed in the ascending aorta and abdominal aorta for staged repairs to be performed subsequently [7]. omplications The elephant trunk procedure is associated with typical aortic surgery complications and with a unique set of complications [9 13] (ppendix 1). s with other aortic graft surgeries, the elephant trunk procedure is associated with a risk of graft occlusion, graft kinking, neurologic dysfunction (stroke, encephalopathy, spinal cord injury), mediastinitis, renal insufficiency, the need for tracheostomy, hemorrhage necessitating thoracotomy, and death (cardiac disease, aneurysm rupture, tamponade, sepsis) [2, 3]. Unique complications related to the configuration of the elephant trunk graft include clot formation around the free end of the elephant trunk, peripheral thromboembolism due to graft flapping, left recurrent laryngeal nerve paralysis, and vocal cord paralysis [2, 3]. dditionally, patients with aortic dissection can develop entrapment of the free end of the graft within the true or false lumen, eliminating flow in the other lumen and perfusion of the abdominal branches that arise from that JR:197, December 2011 W1053

3 Johnson et al. lumen. This complication can be averted by preemptive excision of the dissection membrane beyond the end of the graft [2, 8]. Some surgeons have advocated the use of oral anticoagulation therapy after placement of the elephant trunk graft to prevent thromboembolic complications from the turbulent flow in the area of the descending thoracic aorta and the free-floating elephant trunk graft. Indeed, some chronic laminated thrombus is seen in the recesses of the graft suture line to the distal aortic arch, but our experience with the procedure has not yielded any evidence of distal clot migration. s a matter of routine, all patients who undergo arch aneurysm reconstruction with the elephant trunk technique undergo postoperative T angiography to assist in planning the second stage of the procedure and documenting the length and position of the free-floating descending thoracic aortic graft. Evidence of embolization on those scans manifesting as renal or splenic infarct has not been appreciated. Mortality The mortality rates for each stage, the time intervening between surgeries, and long-term follow-up have been reported in a number of articles. For stage I, operative and 30-day mortality rates range from 5% to 14% [2, 3, 8 10]. The mortality rate for patients awaiting the second surgery is between 2% and 11% [2, 3, 8, 9], with death often caused by rupture of the descending thoracic aorta [9]. For the second surgery, the early mortality rates are reported to be between 0% and 10% [3, 9, 10]. Some patients do not undergo the second surgery. These patients are described as nonreturning, and their mortality rates range from 18% to 31% [3, 9]. s expected, overall survival is higher for those who undergo both surgeries. For example, 5-year survival rates have been reported as 71 82% after complete repair versus 34 50% after only stage I of the procedure [2, 3, 11]. The mortality rate associated with the elephant trunk technique also varies according to the underlying abnormality or disease. One series reported that the lowest early mortality rate was for patients with chronic dissection and that the highest mortality rate was in the setting of acute dissection (100%, 3/3) [8]. Emergent repair was associated with a hospital mortality of 25% versus 7.3% for elective repair in another series [2]. dditionally, operative mortality for the first surgery is increased in the setting of concomitant coronary artery bypass graft [10]. onclusion We hope that the reader has gained an understanding of the rationale behind a staged surgery for aortic aneurysm repair and, through illustrations and images shown here, of the surgical technique, the normal postoperative imaging appearance, and the potential complications of the elephant trunk procedure. References 1. ervantes J. Reflections on the 50th anniversary of the first abdominal aortic aneurysm resection. World J Surg 2003; 27: Schepens M, Dossche KM, Morshuis WJ, van den arselaar PJ, Heijmen RH, Vermeulen FE. The elephant trunk technique: operative results in 100 consecutive patients. Eur J ardiothorac Surg 2002; 21: Safi HJ, Miller 3rd, Estrera L, et al. Staged repair of extensive aortic aneurysms: long-term experience with the elephant trunk technique. nn Surg 2004; 240: ; discussion, orst HG, Walterbusch G, Schaps D. Extensive aortic replacement using elephant trunk prosthesis. Thorac ardiovasc Surg 1983; 31: rawford ES, oselli JS, Svensson LG, Safi HJ, Hess KR. Diffuse aneurysmal disease (chronic aortic dissection, Marfan, and mega aorta syndromes) and multiple aneurysm treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation. nn Surg 1990; 211: Svensson LG. Rationale and technique for replacement of the ascending aorta, arch, and distal aorta using a modified elephant trunk procedure. J ard Surg 1992; 7: arrel T, erdat P, Kipfer, Eckstein F, Schmidli J. The reversed and bidirectional elephant trunk technique in the treatment of complex aortic aneurysms. J Thorac ardiovasc Surg 2001; 122: Heinemann MK, uehner, Jurmann MJ, orst HG. Use of the elephant trunk technique in aortic surgery. nn Thorac Surg 1995; 60:2 6; discussion, 7 9. Safi HJ, Miller 3rd, Estrera L, et al. Staged repair of extensive aortic aneurysms: morbidity and mortality in the elephant trunk technique. irculation 2001; 104: LeMaire S, arter S, oselli JS. The elephant trunk technique for staged repair of complex aneurysms of the entire thoracic aorta. nn Thorac Surg 2006; 81: ; discussion, Svensson LG, Kim KH, lackstone EH, et al. Elephant trunk procedure: newer indications and uses. nn Thorac Surg 2004; 78: Kouchoukos NT. omplications and limitations of the elephant trunk procedure. nn Thorac Surg 2008; 85: ; author reply, Koshino T, Kazui T, Tamiya Y, et al. Impending rupture of the descending aorta by enlargement of the false lumen after graft replacement with the elephant trunk technique: report of a case. Surg Today 1999; 29: PPENDIX 1: Potential omplications fter the Elephant Trunk Procedure [2, 3, 9 13] omplications Graft occlusion Graft kinking Neurologic dysfunction (stroke, encephalopathy, spinal cord injury) Mediastinitis Need for tracheostomy Renal insufficiency Hemorrhage necessitating thoracotomy Death (cardiac disease, aneurysm rupture, tamponade, sepsis) lot formation around the free end of the elephant trunk prosthesis Peripheral thromboembolism due to graft flapping Left recurrent laryngeal nerve paralysis Vocal cord paralysis W1054 JR:197, December 2011

4 Elephant Trunk Procedure for ortic neurysm Repair Fig. 1 Stage I of elephant trunk procedure: surgical repair of ascending thoracic aorta., Illustration depicts surface anatomy of type aortic dissection with thrombosed false lumen and aneurysm., Oblique sagittal section shows extent of aortic dissection. Upper inset shows ascending aorta, arch, and proximal descending aorta. Lower inset shows axial crosssection of true and false lumens, latter of which is thrombosed., Illustration and inset show division of ascending aorta and roof of aortic arch (dashed lines). Great vessels and portion of roof are isolated and retained for later anastomosis with graft. D, Removal of ascending aorta and arch. Upper inset shows great vessels and lower inset, exposed aortic root. D JR:197, December 2011 W1055

5 Johnson et al. D Fig. 2 Step-by-step demonstration of graft invagination for anastomosis preparation and creation of elephant trunk prosthesis., Folding graft in on itself. Outer wall of graft (pink) will be limb that remains in descending aorta. Inner wall of graft (blue) will be pulled superiorly for anastomosis with ascending root and great vessels., Graft placement into descending aortic lumen. Inset shows coronal cross section., nastomosis of graft with descending thoracic aorta. Inset shows coronal cross section. D, Proximal end of retracted graft is sutured to aortic root. Superior limb of graft (blue) is being pulled proximally (arrow) from descending aortic lumen after anastomosis, leaving descending limb (elephant trunk) in descending thoracic aorta. Inset shows coronal cross section. E, omplete anastomosis of superior (ascending) limb of graft prosthesis. E W1056 JR:197, December 2011

6 Elephant Trunk Procedure for ortic neurysm Repair D Fig year-old woman with aortic dissection who presented for follow-up after undergoing ascending aortic repair and elephant trunk procedure., xial IV contrast-enhanced T images show elephant trunk prosthesis (arrows) in descending thoracic aorta. D and E, oronal (D) and sagittal oblique (E) volume renderings nicely convey 3D relationship of free-floating elephant trunk graft (arrows) in descending thoracic aorta. F, Sagittal oblique multiplanar reconstruction shows both elephant trunk prosthesis (arrows) and residual dissection (arrowheads) in descending thoracic aorta. F E JR:197, December 2011 W1057

7 Johnson et al. Fig. 4 Stage II of elephant trunk procedure: surgical repair of descending thoracic aorta., Incision (dashed lines) of 8 10 cm is made through posterolateral descending thoracic aortic wall, exposing elephant trunk graft., nastomosis of distal end of elephant trunk to descending thoracic aorta., ompleted two-stage surgical repair of dissection involving ascending and descending thoracic aorta. Fig year-old woman with extensive thoracic aneurysm. and, oronal () and sagittal () multiplanar reconstructions show aneurysm of thoracic and abdominal aorta with moderate mural thrombus in descending thoracic aorta and proximal abdominal aorta. (Fig. 5 continues on next page) W1058 JR:197, December 2011

8 Elephant Trunk Procedure for ortic neurysm Repair F D G Fig. 5 (continued) 71-year-old woman with extensive thoracic aneurysm. E, Patient underwent ascending aorta repair with elephant trunk prosthesis in descending thoracic aorta. oronal () and sagittal (D) volume renderings and sagittal oblique maximum intensity projection (E) show ascending aortic graft, elephant trunk in descending aorta, and metallic markers (arrows, E) at free end of graft. F H, Multiple stents were placed in descending thoracic aortic aneurysm under fluoroscopy, beginning at distal portion of elephant trunk prosthesis; end of graft is identified by radiopaque markers (arrows, F). I, Sagittal oblique color-coded volume-rendering image shows thoracic aorta after staged surgical repair of ascending thoracic aorta and placement of multiple stents in descending thoracic aorta. FOR YOUR INFORMTION This article is available for ME credit. See for more information. E H I JR:197, December 2011 W1059