Transient oculomotor nerve palsy after topical administration of intracisternal papaverine

Abstract

Dear Editor, We present three patients who suffered aneurysmal subarachnoid hemorrhage with mean age of 48 years. Two patients had middle cerebral artery aneurysms and the third had an anterior communicating artery aneurysm. All three patients underwent a standard frontotemporal craniotomy for clipping of ruptured aneurysm. All three aneurysms were clipped without the need for temporary occlusion and, in no case, was dissection or direct visualization of the oculomotor nerve necessary to obtain proximal control. Local vasospasm was visually apparent in the exposed carotid circulation in all three cases; thus topical 3–5 cc of a 3% solution of papaverine was administered after surgical clipping was completed. Immediate postoperative exam in all three cases revealed isolated ipsilateral oculomotor nerve palsy. The patients had no other neurological deficits suggestive of a space-occupying lesion or raised intracranial pressure. An immediate postoperative CT head was performed (Fig. 1) that only revealed expected postoperative changes and some intracranial air. In all three patients, the deficit resolved completely within a 24-h period (range 3–24 hours). Further recovery was uneventful and all three of these patients were discharged home without focal neurological deficit. Papaverine is a natural heterocyclic nitrogen alkaloid found in opium. It is a commonly used vasodilator that acts directly on smooth muscle. Based on clinical and experimental data, topical application of papaverine for reversal of vasospasm was first advocated by Pool in 1958 [8, 9]. Since then, papaverine has been used by neurosurgeons topically when encountering intraoperative visual evidence of vasospasm [3, 10]. There have been isolated case reports of facial nerve palsies [2, 6, 7], auditory nerve palsy [1], and pupillary changes [3, 10]. Although it may be common knowledge, a review of literature did not yield any prior reports of transient oculomotor nerve palsy (TONP) after topical/intracisternal papaverine use. Transient oculomotor nerve palsy after surgical clipping for aneurysms occurs in 2.9% to 32% of cases depending on the location of the aneurysm. In many cases, the phenomenon has been attributed to traction, mechanical irritation, or transient loss of blood supply to the oculomotor nerve [4, 5]. In our cases, the TONP was seen in the absence of any of the known risk factors. No manipulation of or dissection around the oculomotor nerve was performed in our three cases. Since these cases were observed, we have introduced a practice change by diluting the 3% papaverine solution to 0.3% with normal saline. In our experience, such dilution leads to satisfactory reversal of arterial spasm while preventing the transient oculomotor nerve palsies. Mechanistic explanation of the mode of action of papaverine in causing TONP is unknown. Animal studies combined with in vitro analysis of the mechanisms of action of papaverine are needed to further elucidate this important effect. Further prospective studies are needed to P. Chittiboina :A. Nanda :B. Guthikonda (*) Department of Neurosurgery, LSUHSC Shreveport, P O Box 33932, Shreveport, LA 71130-3932, USA e-mail: bguthi@lsuhsc.edu