A Chronic Contained Rupture of an Abdominal Aortic Aneurysm Complicated with Severe Back Pain

Yasu t sugu N a k a g a w a , MD, Masah i sa Masuda , MD, Hideshige Shiihara, MD, Hitoshi F u r u k a w a , MD, Naok i Hayash ida , MD, Hitoshi K a s e g a w a , MD, Hi royuki Abe , MD, Katsuji Okui , MD, Chiba, Japan

Chronic contained rupture of an abdominal aortic aneurysm is an uncommon occurrence with the aneurysms usually small-to-moderate in size. Diagnosis may be difficult because patients present with both atypical and chronic symptoms. Pres- sure erosion of the lumbar spine is presumably a highly significant associated disorder, but an enhanced computed tomographic scan is the most reliable method for the correct diagnosis. We report on a 46-year-old man who developed severe back pain which was initially thought to result from spinal disease. Retrospective review of computed tomographic scans taken two years before admission revealed the beginning of the leakage of the aneurysm. Remarkably, the patient remained stable two years after the rupture. (Ann Vasc Surg 1990;4:189-192).

KEY WORDS: Aneurysm; abdominal aortic aneurysm; rupture.

Patients with rupture o f an abdominal aortic aneu- rysm (AAA) typically present as an acute abdominal catastrophe, quickly developing signs and symptoms of severe blood loss. However , in rare cases, the bleeding may gradually occur over a long period o f time without causing hemodynamic deterioration, resulting in a large retroperitoneal hematoma. This report describes such a chronically ruptured A A A which caused a marked destruction o f lumbar vertebrae.

C A S E R E P O R T

A 46-year-old man was referred from an orthopedist who noted an extensive pulsation in his lower abdomen and suspected ruptured AAA. Over three years, he had been treated for persistent lower back pain which had grown progressively worse during the previous two months. He had increasing difficulty lying on his back, and he also noted a radiating pain in his left thigh.

The patient's history included only mild hypertension and no previous evidence of AAA. He was taking no medication on admission.

From the First Department of Surgery, School of Medi- cine, Chiba University, Chiba, Japan.

Reprint requests: Yasutsugu Nakagawa, MD, First De- partment of Surgery, School of Medicine, Chiba Univer- sity, 1-8-1, lnohana, Chiba City, Chiba 280, Japan.

Physical examination revealed the patient to be alert and in no acute distress. His blood pressure was 150/87 mmHg with a sinus tachycardia at 100 per minute. He was afebrile, but his abdomen was moderately distended and a prominent pulsation was noted throughout the lower abdomen. No discrete masses were palpable.

Laboratory data on admission included WBC 8500, RBC 423 × 10 4, Hct 38.7%, and CRP + 3. A lateral view of a lumbar spine radiograph showed destruction of the anterior part of the vertebral body at L3 and L4 (Fig. 1).

Because of unremitting pain when the patient lay on his back, only a limited CT scan study could be carried out. However, a small abdominal aortic aneurb'sm was iden- tified with wide loss of the left lateral-to-posterior margin and contiguous to a huge hematoma which occupied a large part of retroperitoneal cavity (Figs. 2, 3).

Review of the CT scan done two years previously revealed the beginning of a retroperitoneal hematoma with a small amount of destruction of the vertebral bodies (Fig. 4).

The patient was transferred directly to the operating room, although some confusion arose from the lack of acute clinical manifestations despite the findings of frank rupture of AAA.

On laparotomy we discovered a marked pulsation over the patient's retroperitoneum which was severely scarred. Otherwise there was no evidence of acute intra- peritoneal or retroperitoneal hemorrhage. He had a 4 cm infrarenal aortic aneurysm which, when opened, revealed a 3 cm tear on its posterior aspect. Through this tear, the huge retroperitoneal hematoma had developed, and it

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190 CHRONIC CONTAINED RUPTURE OF AAA ANNALS OF VASCULAR SURGERY

Fig. 1. Lateral radiograph of lumbar spine shows marked smooth, crescent type erosions in anterior margin of vertebral body of L3. Defect of L4 less marked. Intervertebral disk spaces are well main- tained.

extended superiorly to the inferior pole of kidneys and inferiorly to the pelvis. Medially, we could readily see the severely destroyed vertebral bodies. There was no dis- crete encapsulation around the cavity.

A large amount of organized thrombus was evacuated from the lateral side and a bifurcated Dacron graft was inserted. Recovery was uneventful. Microscopic findings revealed an arteriosclerotic aortic aneurysm. The retro- peritoneal hematoma began to decrease in size over a seven month period (Fig. 5).

DISCUSSION The clinical existence of chronic rupture of an

AAA has been known since the concept of " s e a l e d " rupture was first described by Szilagyi and associates in 1961 [1]. The sealed rupture occurs when the rupture is so small that the escape of blood is effectively walled off by the surrounding tissue reaction in the aortic wall. Because the blood loss is stow and protracted, the patient 's hemody- namics remain stable for a varying period of time.

Fig. 2. Plain CT scan demonstrates large homoge- neous retroperitoneal mass continuously posterolat- eral to the anteriorly displaced aorta (A). Note scal- loped erosion along anterior aspect of vertebral body L3 (arrow).

Review of the literature (Table I) documents two salient features associated with this type of rupture. First, the original aneurysms that may manifest this complication are usually small or moderate in size [2-10]. Flinn and coworkers reported in his large series that 54% of the aneurysms were 6 cm or less in diameter on CT scan [I 1]. In some instances a fingerlike focal bulge or minimal aneurysmal change in the wall of the aorta is found at exploration [4,5]. At this stage the aorta is probably still strong enough to contain the tear and minimize its size [12]. Just why aortic tears occasionally develop in such small lesions is not known. Apart from ather- osclerosis, no specific pathological changes of the

Fig. 3. CT scan after intravenous contrast enhance- ment clearly delineates hematoma cavity. Psoas mus- cles (Pro) of both sides are markedly displaced pos- terolaterally by hematoma. Th = thrombus.

VOLUME 4 N o 2 - 1990 CHRONIC CONTAINED RUPTURE OF AAA 191

Fig. 4. Plain CT scan two years before admission. Small retroperitoneal hematoma (H) was already noted. Also, note beginning of erosion of vertebral body.

Fig. 5. Enhanced CT scan seven months following surgery demonstrated marked decrease in size of hematoma (H). G = aortic graft.

aorta have been described, except for one report in which Behqet's disease was suggested as a possible causative factor [13].

Secondly, while most of the patients have symp- toms, they quite often present with unusual mani- festations which may not necessarily prompt phy- sicians to search for aortic rupture. Chronic back pain of variable intensity is most commonly en- countered. If the hematoma dissects into the psoas muscle, femoral or obturator neuropathy may occur [I0,14], and the patient may present with a painful pulsatile mass in the groin [2]. The patient may develop fever and leukocytosis associated with ab- dominal or flank pain that mimics retroperitoneal infection or psoas abscess [4,15]. Painless hema- turia caused by intrarenal rupture [5] or swelling of the legs due to inferior vena caval obstruction by a retroperitoneal hematoma [3] has been reported. Notably, these clinical presentations are not usually accompanied by signs of acute blood loss.

Vertebral erosion is another complication fre- quently occurring in conjunction with this type of rupture [6,10,13,14, I6]. At one time vertebral ero- sion was associated with aortic aneurysms of pri- marily syphilitic origin. Nowadays, it is reported only infrequently with intact and ruptured aneu- rysms [I7]. Since the vast majority of cases of AAA are now of arteriosclerotic origin, their shape is usually fusiform and rarely saccular. The difference in the shape of the aneurysm probably explains the current decline in the vertebral erosion complica- tion [18]. In fact, Lucke and Hague, in 1923, re- ported 17 cases of vertebral erosion in 34 patients with AAA, of which 30 were saccular in shape [19]. Since an aneurysm with a sealed rupture is essen- tially a pseudoaneurysm in origin, its shape is, at least in the beginning, saccular like that of a syph- ilitic aneurysm. A vertebral body can be eroded from pressure exerted by a saccular aneurysm sur- prisingly quickly. The previous CT film in our case clearly demonstrates this phenomenon (Fig. 4).

When the original aortic lesion is small and barely palpable, it can be difficult to make the correct diagno-

TABLE I.--Previously reported cases with chronic contained rupture of abdominal aortic aneurysms

No. of Aneurysm size on Authors Year patients CT (cm) Length of symptoms Outcome

Olcott, et al [2] 1978 1 5.0 - - survived Gertner, et al [3] 1978 1 4.5 3.5 weeks died Clayton, et al [4] 1982 3 fingerlike, 5.0, 8.0 0, 1, 12 days 2, survived Gavant, et al [5] 1986 1 3.8 - - Carruthers, et al [6] 1986 1 5.0 18 months survived Rosenthal, et al [7] 1986 2 5.0, 6.0 w , 4 months all survived Jones, et al [8] 1986 7 6.0-10.0 (av.7.3) 1 wk-6 mos (av.6.5 wks) all survived Nora & Hollier [9] 1987 2 penetrating ulcer, - - 6 weeks all survived Higgins, et al [10] 1988 1 5.0 3 weeks survived Flinn, et al [11] 1989 12 3.0-15.0" (av.7.1) 1 wk-12 mos (av.14.25 wks) 5, died t *54% were 6 cm or less t"2 patients with mycotic aneurysm

ANNALS OF 192 CHRONIC CONTAINED RUPTURE OF AAA VASCULAR SUR6ER¥

sis. Together with the confusing history sometimes given by patients, it is possible to make a serious misdiagnosis. Carruthers and colleagues recently re- ported a case of a patient with destruction of multiple vertebrae by a sealed and ruptured but impalpable AAA [6]. The patient was treated with radiotherapy with presumed metastatic carcinoma to the spine. Percutaneous needle biopsy and retroperitoneal open biopsy were also carried out. Eventually the ruptured AAA was found at exploration and the patient made a rapid recovery after surgery.

To avoid such errors, one should always be aware that puzzling back, flank, or femoral pain may be due to an A A A with sealed rupture. Only this high degree of awareness, along with careful review of an abdominal CT scan with contrast media, can allow correct diagnosis. CT is the most reliable, clear-cut, noninvasive diagnostic tool, and is superior to ultrasonograms in displaying the aorta, especially if it has a surrounding mass [4]. This soft retroperitoneal mass will be displayed contiguous to the posterior aorta, typically silhou- etting the psoas muscle and displacing the kidney.

Patients reported in the literature have often had symptoms for days, weeks, even months, but rarely more than six months (Table I). These time frames are consistent with autopsy findings by Darling; 10% of the patients with sealed rupture of an AAA survived at least six weeks, but no one lived longer than three months [20]. Thus, a sealed rupture is still at high risk for free rupture. It may reopen as the hematoma gradually enlarges with each episode of bleeding with wide rupture and massive extrava- sation finally taking place. Routine use of CT scan has recently made early recognition possible and several cases have been reported as a chronic contained rupture [7,8,10].

Jones and associates have recently clarified the clinical concept of chronic contained rupture and emphasized the need for its differentiation from acute contained rupture which will require immedi- ate operation [8]. Stable patients with chronic con- tained rupture should be treated in an urgent man- ner after full assessment and hydration. Surgical risk is generally comparable to that of elective surgery for intact aneurysm (Table I).

Our patient had an unusually extended survival time after leakage of an aneurysm that was demon- strated by CT scan two years prior to the eventual repair. He remained stable during this interval de- spite having developed a large hematoma in the retroperitoneal space.

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