1
Introduction
Bleeding during modified radical mastoidectomy usually occurs due to injury to dura matter and sigmoid sinus and, in most cases, can be controlled easily. Iatrogenic injury to the carotid artery as it traverses the middle ear in its normal anatomical position is a rare but potentially life-threatening event. Predisposing factors include a thin or dehiscent plate of bone which normally protects the artery at the level of the Eustachian tube, erosive middle ear disease such as cholesteatoma, or previous trauma. Review of literature shows that iatrogenic cases of bleeding from internal carotid artery (ICA) during middle ear surgery are rare, and in almost all the cases, the carotid artery followed an anomalous route through the temporal bone. We report an extremely rare case of a carotid blow out during mastoidectomy and management of the resulting pseudoaneurysm using microcoils via an endovascular approach.
2
Case report
A 20-year-old man with chronic suppurative otitis media of atticoantral type of left ear underwent modified radical mastoidectomy for clearance of cholesteatoma filling the middle ear cleft (attic, aditus, meso, and hypotympanum). During the procedure, there was a sudden gush of bright red blood filling the entire operative field without a clearly identifiable bleeding point. The surgery was abandoned, and the ear was packed tightly, but the patient continued to bleed intermittently through the nose and oral cavity via the Eustachian tube.
Magnetic resonance angiography (MRA) revealed an injury to the intratemporal segment (anteroinferior to the middle ear cavity) of the ICA along its normal course. Patient was then subjected to conventional carotid angiography with coiling of pseudoaneurysm via an endovascular approach ( Fig. 1 A-C).
The ear pack was removed after 2 days. Two weeks later, the cavity had epithelized nicely ( Fig. 2 ), and there have been no episodes of bleeding ever since.
2
Case report
A 20-year-old man with chronic suppurative otitis media of atticoantral type of left ear underwent modified radical mastoidectomy for clearance of cholesteatoma filling the middle ear cleft (attic, aditus, meso, and hypotympanum). During the procedure, there was a sudden gush of bright red blood filling the entire operative field without a clearly identifiable bleeding point. The surgery was abandoned, and the ear was packed tightly, but the patient continued to bleed intermittently through the nose and oral cavity via the Eustachian tube.
Magnetic resonance angiography (MRA) revealed an injury to the intratemporal segment (anteroinferior to the middle ear cavity) of the ICA along its normal course. Patient was then subjected to conventional carotid angiography with coiling of pseudoaneurysm via an endovascular approach ( Fig. 1 A-C).
The ear pack was removed after 2 days. Two weeks later, the cavity had epithelized nicely ( Fig. 2 ), and there have been no episodes of bleeding ever since.
3
Discussion
The ICA enters the temporal bone through the external carotid foramen, located just anteromedial to the styloid process. As it ascends in its intrapetrous segment, it passes first anterior to the tympanic cavity and cochlea and then bends (its “knee”) to run medial to the Eustachian tube and inferomedial to the semicanal of the tensor tympani muscle. The artery then climbs to exit the temporal bone at the internal carotid foramen and enters the middle cranial fossa. Accompanying the artery throughout its intrapetrous course are a venous and a neural (sympathetic) plexus. Under normal circumstances, the bony shell protecting the artery is extremely thin (usually about one fourth of a millimeter in thickness) and can be dehiscent in about 6% of cases . Although the artery is separated by a ledge of bone from the middle ear, this can some time be absent or dehiscent because of the failures in ossification, congenital anomaly, persistence of embryonic vessels (persistence of pharyngeal artery system) , bone absorption, or inflammatory processes of middle ear. In all such cases, there is always a chance of damage to ICA.
Kimmelman and Grosman have reported a case of ICA aneurysm resulting from granulomatous tissue eroding the underlying bone in a case of long-standing otitis media. In another case reported by Barrett and Lawrence , a patient who had undergone a radical mastoidectomy developed postoperative bleeding because of development of an aneurysm of the ICA. Even without external injury or injury during surgery, spontaneous cases of bleeding have been reported in cases of cholesteatoma. One such case of spontaneous carotid blow out has been reported by Riley and Anderson . In the above case, the ICA was damaged during the process of removal of granulations and cholesteatoma by blunt dissection from the anteroinferior wall of the tympanic cavity.
In addition to this, developmental anomalies can lead to catastrophic bleeding during surgical procedures. Reilly et al have reported a case of injury to an aberrant ICA during biopsy after myringotomy for a suspected middle ear tumor that resulted in a massive hemorrhage. Stallings and McCabe and Goodman and Cohen have reported cases of injury to congenital aneurysms of ICA within middle ear.
At our institution and as suggested in a study by Walshe et al , a preoperative computed tomographic (CT) scan should be done in cases of children, patients with diseased ear as the sole or better hearing ear, patients in whom the tympanic membrane cannot be adequately visualized, patients undergoing revision mastoid surgery, and patients with intratemporal or intracranial complications of the disease . As this adult patient was a case of unilateral Chronic suppurative otitis media of atticoantral type without complication and with a normal hearing in the other ear, a preoperative CT scan was not done. However, recently, it has been suggested that if a retrotympanic mass with aberrant ICA characteristics (anterior, pulsatile and red colored) is observed during middle ear surgery, a CT Scan should be performed before puncture or biopsy and in order to avoid injury due to misdiagnosis, or to look for any aberrant carotid artery, a computed tomographic (CT) scan of the temporal bone should be performed before any middle ear surgery .
In any case where profuse bleeding occurs during mastoid surgery without an identifiable bleeding point, the surgery should be abandoned, ear packed tightly and patient subjected to an urgent magnetic resonance angiography (MRA) to identify the cause of hemorrhage and localize the point of injury or pseudoaneurysm formation and status of intracranial aneurysm . The resulting pseudoaneurysm should be treated as early as possible to avoid rupture and catastrophic hemorrhage. The options available would be:
- 1)
Packing the ear and applying pressure bandage. This would be a temporary method for achieving hemostasis and shifting the patient to a centre where facilities for MRA and interventional radiology/cardiology are available, as was done in our case.
- 2)
Proximal and distal carotid artery ligation or embolization of ICA using balloons . This has the disadvantage of high incidence of stroke and neurological deficit. In addition, distal ICA ligation would require a craniotomy resulting in additional morbidity.
- 3)
Stenting the carotid artery using a self-expanding wall graft as recommended by Matsuura et al or balloon expandable stent grafts (ie, covered Jo-stent graft) is another alternative but would subject a patient to a prolonged (life-long) exposure to dual antiplatelet drugs (aspirin and clopidogrel), which is associated with a risk of systemic bleed (eg, GI tract/intracranial).
- 4)
We opted for occlusion of the pseudoaneurysm using microcoils via an endovascular approach without compromising the distal flow. The technical difficulty and morbidity associated with surgical treatment of ICA injury makes an endovascular approach using microcoils an appealing alternative.
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