Locked-in syndrome: a catastrophic complication after surgery{dagger}

P. Breen* and V. Hannon

Department of Anaesthesia Intensive care and Pain Management, St Vincent’s University Hospital, Elm Park, Dublin 4, Ireland

*Corresponding author: Intensive Care Unit, Middlesex Hospital, Mortimer Street, London W1T 8AA, UK. E-mail: patrickbreen@eircom.net
{dagger}Presented on 16 May 1997 at the Annual Scientific Meeting, Royal College of Anaesthetists, Royal College of Surgeons in Ireland, Dublin, Ireland.

Accepted for publication: August 18, 2003


    Abstract
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
We describe the locked-in syndrome in a 31-yr-old patient after right upper lobectomy for suspected metastasis. After surgery, vertical eye movement was her only means of communication. She remained in a ‘locked-in’ state for 7 months before dying. Post-mortem examination showed extensive metastatic tumour deposition in the ventral pons. We discuss the clinical features of this syndrome and factors that may affect onset, diagnosis and management.

Br J Anaesth 2004; 92: 286–8

Keywords: brain, ventral pons; complications, cranial nerve palsy; complications, postoperative neurological deficit; complications, synovial sarcoma; complications, tetraplegia


    Introduction
 Top
 Abstract
 Introduction
 Case report
 Discussion
 References
 
Locked-in syndrome is characterized by tetraplegia and lower cranial nerve palsies in a conscious patient. Vertical eye movements and blinking are the only means of communication.1 The aetiology is multifactorial, with the lesion usually in the ventral pons. Locked-in syndrome can occur in the perioperative period.2 We describe a case after lobectomy, and identify factors that may affect onset, diagnosis and management.


    Case report
 Top
 Abstract
 Introduction
 Case report
 Discussion
 References
 
A 31-yr-old woman, ASA I, underwent right upper lobectomy for a suspected metastatic lesion from a synovial sarcoma in her left elbow, which had been treated with surgical excision and radiotherapy 16 yr previously. Chest radiography was done to investigate left shoulder pain and a lung lesion was found. No evidence of vascular or neurological disease was found before surgery. She was a non-smoker and took no medication.

Anaesthesia was induced with fentanyl and propofol. Vecuronium 6 mg was given to allow insertion of a left-sided, double-lumen endobronchial tube and a further 4 mg to maintain neuromuscular blockade. Anaesthesia was maintained using isoflurane (FE' 0.5–1.5%) with nitrous oxide 66–0% in oxygen. Arterial and central venous pressures were measured with appropriate cannulae. The patient was carefully positioned on her left side with the head and neck in a neutral position, and a right upper lobectomy was performed. Systolic pressure remained within 20% of the conscious value, which was 110 mmHg. SpO2 was never less than 95%. Morphine was given for analgesia (total intraoperative dose 10 mg), and intercostal blocks were done under direct vision by the surgeon, using bupivacaine 0.25%, 10 ml.

Neostigmine 2.5 mg and glycopyrrolate 0.5 mg were given i.v. to antagonize neuromuscular blockade, and spontaneous respiration started. Oxygen 100% was given and the patient was carefully placed in the supine position with the head and neck in the neutral position. She remained deeply unconscious. Her vital signs were stable. The trachea remained intubated. The pupils were constricted and did not react to light. A painful stimulus caused eye opening and decerebrate posturing. Arterial blood gas analysis and blood glucose values were normal. A computed axial tomographic (CAT) brain scan, done without contrast enchancement, showed no abnormality. Blood electrolytes, and renal and liver function tests were normal.

The following morning, a second CAT scan was performed with contrast enchancement. This showed two low-density lesions in the right cerebellar hemisphere, one in the left side of the pons and one in the thalamus. The patient received ventilatory support and was sedated with morphine and midazolam. Four days later a diagnosis of locked-in syndrome was confirmed. The only voluntary effort was vertical eye movement. The patient was able to understand and respond appropriately to commands. She communicated by moving her eyes upwards for no and downwards for yes.

Histological examination of the resected lobe of lung confirmed metastatic synovial sarcoma. Tumour was present within and adjacent to the pulmonary vein.

The patient’s neurological condition remained stable, with no arm or leg movement. After tracheostomy, she breathed spontaneously. A magnetic resonance scan showed probable metastatic disease in the brain stem. The patient remained in a locked-in state and died 7 months later.

Post-mortem examination revealed a basilar artery occlusion caused by a tumour embolus (metastatic synovial sarcoma). The ventral pons was extensively replaced with metastatic tumour. The tumour appeared to arise from within the artery, extending through the vessel wall into the surrounding pons. It was not possible to determine when tumour embolism had occurred. Other findings were a small intraventricular haemorrhage, bilateral Wallerian degeneration of the corticospinal tracts at the level of the pons, caused by metastatic tumour, bilateral symmetrical olivary hypertrophy, and sarcomatous metastases in both kidneys and in the right adrenal gland.


    Discussion
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
The first description of locked-in syndrome was probably in 1868. In Thérèse Raquin, Emile Zola wrote that one of his characters ‘‘could communicate quite easily with that imprisoned mind buried alive in a dead body’’.3 The term locked-in syndrome is attributed to Plum and Posner, who described a 44-yr-old man with complete occlusion of the basilar artery.1 This patient was conscious but could communicate using eye movements only.

Locked-in syndrome is usually caused by pontine infarction after prolonged vertebrobasilar ischaemia.4 Other causes include haemorrhage, tumour,5 trauma,6 central pontine myelinolysis,7 pontine abscess,8 interscalene brachial plexus blocks9 and postinfective polyneuropathy.10 Cerebral air embolism and transient vertebrobasilar insufficiency are potentially reversible causes. The site of the lesion is usually in the basis pontis and there may be variable involvement of the pontine tegmentum, medulla and midbrain.1 Preservation of voluntary eye movements occurs when the lesion remains caudal to the nucleus of the oculomotor nerve; consciousness is preserved when the reticular formation in the dorsal pons is unaffected by the lesion. The diagnosis can be made clinically. The prognosis after ventral pontine infarction is often fatal from respiratory failure or extension of the infarct. Recovery can occur from the locked-in syndrome,11 but most survivors remain in a chronic locked-in state or are severely impaired. Significant recovery may occur when the duration of the syndrome is less than 24 h, usually after a transient ischaemic attack.

Perioperative locked-in syndrome following coronary artery bypass graft has been described on two occasions.2 12 One case, occurring a few hours after surgery, was attributed to cerebral air embolism, with air bubbles noted in the grafts during surgery.12 Recovery was complete after treatment in a hyperbaric oxygen chamber. Kenny and colleagues2 described basilar artery embolism causing the syndrome within 24 h of surgery. The patient remained in a locked-in state.

We suspect that our patient developed locked-in syndrome from a tumour embolus that occurred during surgery. The clinical features were not apparent at first. Decerebrate posturing is not typical. The low-density changes seen on the contrast-enhanced CAT scan may have been caused by infarction. This was confirmed at autopsy. Tumour was found in the pulmonary vein of the resected lobe. The pulmonary artery is usually ligated before the vein. This reduces bleeding from the lung during resection but may increase the likelihood of tumour embolization.

How relevant is this case report to anaesthetic practice? The locked-in syndrome is an unlikely reason for delayed recovery from anaesthesia, and other causes should be excluded first. Some patients may have an increased risk of developing the syndrome during surgery. Cervical osteoarthritis can cause vertebrobasilar insufficiency if osteophytes compress the vertebral artery during neck movements. Patients with this condition should therefore be positioned carefully when anaesthetized, with their head and neck in the neutral position. Inadvertent vertebral artery injection during interscalene brachial plexus block may cause the syndrome. Emboli from atheroma can occur after cannulation of an atherosclerotic proximal aorta.13 This is best detected by epiaortic ultrasonography.14 Locked-in feelings have also been reported in patients receiving neurolept anaesthesia.15 Synovial sarcomas are malignant high-grade neoplasms that account for 7–8% of all malignant soft-tissue tumours and are quite common in young people. Complete resection remains the treatment of choice.16

We present a case of locked-in syndrome associated with metastatic disease. Careful preoperative evaluation may serve to identify patients at particular risk of developing such complications during surgery.


    References
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
1 Plum F, Posner JB. The diagnosis of stupor and coma. Philadelphia: FA Davis, 1982; 377

2 Kenny DJ, Luke DA. ‘Locked-in’ syndrome – occurrence after coronary artery bypass graft surgery. Anaesthesia 1989; 44: 483–4[ISI][Medline]

3 Pearce JMS. The locked-in syndrome. BMJ 1987; 294: 198–9[ISI][Medline]

4 Patterson JR, Gravois M. Locked in syndrome: a review of 139 cases. Stroke 1986; 17: 758–64[Abstract]

5 Cherington M, Stears J, Hodges J. Locked-in syndrome caused by a tumour. Neurology 1976; 26: 180–2[Abstract]

6 Fox C, Lavin M. Vertebral artery dissection resulting in locked-in syndrome. Neurosci Nurs 1991; 23: 287–9

7 Adams RD, Victor M, Mancall EL. Central pontine myelinolysis: A hitherto undescribed disease occurring in alcoholic and malnourished patients. Arch Neurol Psychiatry 1959; 81: 154–72[ISI]

8 Murphy MJ, Brenton DW, Aschenbrener CA, Van Gilder JC. Locked-in syndrome caused by a solitary pontine abscess. J Neurol Neurosurg Psychiatry 1979; 42: 1062–5[Abstract]

9 Durrani Z, Winnie A. Brainstem toxicity with reversible locked-in syndrome after intrascalene brachial plexus block. Anesth Analg 1991; 72: 249–52[ISI][Medline]

10 Thadani VM, Rimm DL, Urquhart L, et al. ‘Locked-in syndrome’ for 27 years following a viral illness: clinical and pathological findings. Neurology 1991; 41: 498–500[Abstract]

11 McCusker EA, Rudick RA, Honch GW, Griggs RC. Recovery from the ‘locked-in’ syndrome. Arch Neurol 1982; 39: 145–7[Abstract]

12 Newman RP, Manning EJ. Hyperbaric chamber treatment for ‘locked-in’syndrome. Arch Neurol 1980; 37: 529[CrossRef][ISI][Medline]

13 Barbut D, Yao FS, Hager DN, Kavanaugh P, Trifiletti RR, Gold JP. Comparison of transcranial Doppler ultrasonography and transesophageal echocardiography to monitor emboli during coronary artery bypass surgery. Stroke 1996; 27: 87–90[Abstract/Free Full Text]

14 Royse C, Royse A, Blake D, Grigg L. Screening the thoracic aorta for atheroma: a comparison of manual palpation, transoesophageal and epiaortic ultrasonography. Ann Thorac Cardiovasc Surg 1998; 4: 347–50[Medline]

15 Linnemann MU, Guldager H, Nielsen J, Ibsen M, Hansen RW. Psychomimetic reactions after neurolept and propofol anaesthesia. Acta Anaesthesiol Scand 1993; 37: 29–32[Medline]

16 Andrassy RJ, Okcu MF, Despa S, Raney RB. Synovial sarcoma in children: surgical lessons from a single institution and review of the literature. J Am Coll Surg 2001; 192: 305–13[CrossRef][ISI][Medline]





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