Posterior Shoulder Dislocation As a Post-Operative Complication of Carotid Endarterectomy: Case Report and Review of Literature

Idit Melnik, Ehud Atoun, Ronen Debi, Yafim Harach, Ofer Levy, Ornit Cohen, Boris Yoffe

Idit Melnik, Yafim Harach, Boris Yoffe, Department of General and Vascular Surgery, Barzilai Medical Center, Ashkelon, Israel; Affiliated with the Faculty of Health Sciences, Ben-Gurion University of the Negev.
Ehud Atoun, Ronen Debi, Ornit Cohen, Department of Orthopedics, Barzilai Medical Center, Ashkelon, Israel; Affiliated with the Faculty of Health Sciences, Ben-Gurion University of the Negev.
Ofer Levy, Reading Shoulder Unit, Royal Berkshire Hospital, Reading, the United Kingdom

Conflict-of-interest statement: The author(s) declare(s) that there is no conflict of interest regarding the publication of this paper.
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Correspondence to: Ehud Atoun MD, Department of Orthopedics, Barzilai Medical Center, Ashkelon, Israel.
Email: dratoun@gmail.com
Telephone: +972577678722
Fax: +97246380044

Received: June 14, 2016
Revised: January 18, 2017
Accepted: January 22 2017
Published online: April 28, 2017


Changes in blood pressure after carotid endarterectomy (CEA) may lead to the cerebral hyperperfusion syndrome (CHS), which might be accompanied by postoperative seizures. We report a case of a 71-year old man that underwent left CEA and developed a tonic-clonic seizure in the recovery room after hearing a familiar voice. Physical and radiological imaging revealed a massive rotator cuff tear and locked posterior shoulder dislocation of the right humerus with a large impaction fracture. He was successfully treated with a reverse shoulder arthroplasty and gained good functional results.

Key words: Shoulder, Dislocation, Carotid enartherectomy, Seizure

© 2017 The Author(s). Published by ACT Publishing Group Ltd. All rights reserved.

Melnik I, Atoun E, Debi R, Harach Y, Levy O, Cohen O, Yoffe B. Posterior Shoulder Dislocation As a Post-Operative Complication of Carotid Endarterectomy: Case Report and Review of Literature. International Journal of Orthopaedics 2017; 4(1): 730-732 Available from: URL: http: //www.ghrnet.org/index.php/ijo/article/view/1756


Carotid endarterectomy (CEA) is most commonly performed for a high-grade internal carotid artery stenosis. Manipulation of the carotid bulb during carotid endarterectomy may results in hemodynamic instability intraoperatively and in the early postoperative period. Thus, it is standard care for CEA patients to be placed in a monitored setting of blood pressure. Those changes in blood pressure may lead to the cerebral hyperperfusion syndrome (CHS), a rear syndrome which causes most of postoperative intracerebral hemorrhages and seizures in the first two weeks after surgery.

Posterior shoulder dislocation has repeatedly been reported as a complication of convulsive disorders. The dislocation is frequently accompanied by a massive rotator cuff tear and an aterior humeral head impaction fracture (reverse hill sachs lesion).

We report a case of a posterior fracture dislocation of the shoulder with a massive rotator cuff tear following CEA. This is a complication that has not been previously reported in the literature.


A 71-year-old man with a history of diabetes mellitus, coronary artery disease, and peripheral arterial disease underwent a left CEA with Dacron patch angioplasty for asymptomatic high-grade stenosis under general anesthesia in April of 2012 at our institution. The procedure was technically unremarkable. The patient was anticoagulated with intravenous Heparin. A Dacron patch was used for closure of the common and internal carotid arteries. After extubation, during recovery from the anesthesia the patient was hypertensive with blood pressure up to 204/83. He was treated with beta-blockers and intravenous nitroglycerine with partial response. Blood test revealed mild hyponatremia, hypomagnesemia and hypocalcemia. When the patient’s wife entered the recovery room, immediately after hearing her voice he developed a tonic-clonic seizure and lost conscious. He was re-intubated and admitted for further treatment in the ICU. Post seizure brain CT failed to demonstrate cerebrovascular attack. He gradually underwent extubation with no recurrence of a hypertensive episode.

While gaining conscious he started to complain of pain in his right shoulder. Physical examination revealed locked internal rotation of the upper limb with a void in the anterior aspect of the shoulder. CT scan of the shoulder revealed a posterior dislocation of the humerus with a large impaction fracture of the humeral head (Figure 1) and severe fatty degeneration of the supraspinatous and infraspinatous. US scan of the shoulder revealed a massive rotator cuff tear. The patient refused to further treatment at this stage, therefore, no attempt for close reduction of the dislocation was perfumed. In the early post- operative period the patient had marked limitation of range of motion with severe pain therefore he decided to go through with surgery six weeks after the dislocation. Due to the time from injury, size of the bony and tendon injury and his age the patient was a candidate for reverse shoulder arthroplasty that allows shoulder function in the absence of rotator cuff. The surgery underwent without complication (Figure 2) with good functional results at three years follow up.

Figure 1 Axial CT image of posterior dislocation of humerous.

Figure 2 AP post- operative X-ray of rt. shoulder.


Hymodynamics alternations after CEA (as the hypertensive crises presented in our case) can lead to a cerebral hyperperfusion syndrome (CHS) or hypertensive encephalopathy (HE).

The term cerebral hyperperfusion syndrome was first reported by Sundt et al[5] in 1981. He described the triad of ipsilateral migrainous headache, focal neurological deficit and seizure in the absence of cerebral ischemia following CEA. It was suggested that there might be a synergistic link between CHS and HE. It does seem increasingly likely that the two are interlinked and may represent synergistic triggers for a subsequent “common pathway”. Considering the two syndromes together might explain the early post CEA seizure as was observed in our case.

The incidence of CHS after CEA is 0-3%, although some report an incidence as high as 18.9%[1]. The pathophysiology of CHS is due to impaired baseline cerebral autoregulation mechanisms as arterioles are already maximally dilated to account for the altered cerebral perfusion secondary to carotid stenosis[2]. In the presence of an impaired cerebral autoregulation mechanism, changes in systemic arterial pressure have a direct effect on CBF. This concurs with the ‘impaired perfusion pressure breakthrough theory’, which suggests that the structurally weaker capillaries in chronically ischemic brain are more likely to rupture and bleed due to the distension during reperfusion[4].

As mentioned above, one of the symptoms of CHS and HE is focal motor seizures. Those, Post endartherctomy seizures are a rare complication that raises a major concern. Naylor et al reported a series of eight patients who developed post endarterectomy seizures, seven of which developed post-ictal neurological deficit (stroke-5, TIA-2), all had had significantly elevated blood pressure at onset of seizures[1].

Our case correlates with those prior reports of an early hypertensive blood pressure after CEA that leads to CHS/HE with a manifestation of a focal motor seizure. However, in this case the sound of a familiar person was the actual trigger for the seizure. This, emphasis the need for a tranquil environment after the surgery.

Posterior shoulder dislocation is rare, accounting for less than 5% of all shoulder dislocation. They are frequently associated with seizures, trauma or electrocution. The mechanism is an unbalanced muscle contraction, which occurs during the seizure when the internal rotator muscles of the shoulder contracts with greater force than the external rotator causing the humeral head to move superiorly and posteriorly[3]. In our case, the dislocation that caused a significant bony injury to the humeral head and a massive rotator cuff tear was successfully treated with reverse shoulder arthroplasty and the patient gained full range of motion after treatment. To our knowledge, this is the first case of a posterior shoulder dislocation as a result of a post endartherctomy seizure.


We report the first case of a posterior shoulder dislocation caused by post endarthrectomy seizure. The patient had CHS and with the trigger of hearing a familiar voice he developed a tonic clonic seizure that resulted in a posterior shoulder dislocation. Physicians treating those patients should be aware of the “post CEA seizure syndrome” and tend to avoid any unnecessary stimulation in the post-operative period and treat post CEA hypertension more aggressively.


1. Naylor AR, Evans J, Thompson MM, London NJ, Abbott RJ, Cherryman G, Bell PR. Seizures after carotid endarterectomy: hyperperfusion, dysautoregulation or hypertensive encephalopathy? Eur J Vasc Endovasc Surg 2003; 26: 39-44. [PMID:12819646]

2. Naylor AR, Whyman MR, Wildsmith JA, McClure JH, Jenkins AM, Merrick MV, Ruckley CV. Factors influencing the hyperaemic response after carotid endarterectomy. Br J Surg 1993; 80: 1523-1527. [PMID: 8298914]

3. Rouleau DM, Hebert-Davies J. Incidence of associated injury in posterior shoulder dislocation: systematic review of the literature. J Orthop Trauma 2012; 26: 246-251. [PMID: 22183196]; [DOI: 10.1097/BOT.0b013e3182243909]

4. Sekhon LH, Morgan MK, Spence I. Normal perfusion pressure breakthrough: the role of capillaries. J Neurosurg 1997; 86: 519-524. [PMID: 9046310]; [DOI: 10.3171/jns.1997.86.3.0519]

5. Sundt TM, Jr., Sharbrough FW, Piepgras DG, Kearns TP, Messick JM, Jr., O’Fallon WM. Correlation of cerebral blood flow and electroencephalographic changes during carotid endarterectomy: with results of surgery and hemodynamics of cerebral ischemia. Mayo Clin Proc 1981; 56: 533-543. [PMID: 9579496]

Peer reviewers: Kanniraj Marimuthu


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