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BRIEF COMMUNICATIONS: J. Y. Ahn, I. B. Han, P. H. Yoon, S. H. Kim, N. K. Kim, S. Kim, and J. Y. Joo Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy Neurology 2006; 66: 121-123 [Abstract] [Full text] [PDF]

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Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy

George KC Wong, Ng SC, Tsang PK, Poon WS   (21 February 2006)

Reply from the Author

Jung Yong Ahn   (21 February 2006)

Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy 21 February 2006
George KC Wong, Department of Surgery Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Ng SC, Tsang PK, Poon WS Send Correspondence to journal: Re: Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy georgewong{at}surgery.cuhk.edu.hk George KC Wong, et al.	We read with interest the article by Ahn et al. [1] Ten patients underwent endovacular coiling and seven patients underwent microsurgical clipping. The authors assessed the recovery of the related third nerve palsy and factors that would predict recovery in both groups. The authors concluded that the endovascular coiling group during follow-up---ranging from 4 to 34 months---three patients (30%) had incomplete recovery and one (10%) remained unchanged after treatment. Presence of diabetes mellitus and degree of third nerve palsy at presentation were significant factors of recovery of third nerve palsy, with P-values of 0.008 and then 0.025. Because data we have collected contradicted Ahn et al's findings, we rechecked the information in the table of their article and noted that factors as presence of diabetes mellitus and degree of third nerve palsy at presentation should be nonsignificant using Fisher's exact test with SPSS Version 10.0. The P-values were 0.444 and 0.167 respectively. In our experience, diabetes mellitus related third nerve palsy usually resolved completely but it might take up to one year. Similarly, recovery from third nerve palsy after endovascular coiling might take up to one year. [2] Shorter follow-up periods in patients might have distorted the results. We agreed with Ahn et al that endovascular coiling was a feasible and effective treatment for patients with third nerve palsy associated with posterior communicating artery aneurysms. Disclosure: The authors report no conflicts of interest.
Reply from the Author 21 February 2006
Jung Yong Ahn, Department of Neurosurgery 351, Yatap-dong, Pundang-gu, Sungnam, 463-712, South Korea Send Correspondence to journal: Re: Reply from the Author jyahn{at}cha.ac.kr Jung Yong Ahn	We thank Wong et al for their comments on our article. [1] They noted the lack of difference between factors as presence of diabetes mellitus and degree of third nerve palsy (TNP) at presentation and recovery of TNP. We agree that an uncontrolled analysis and shorter follow-up period of prognostic factors in patients with posterior communicating artery aneurysm and TNP might be misleading. In our results, contrary to the previous report, the presence of diabetes, older age, delayed intervention, and complete TNP at presentation, were poor prognosticators of complete recovery in the coiling group. In the microsurgical clipping group, patient age was the only significant factor of recovery of TNP. The factors of recovery of TNP were different between the two treatment groups and between microvascular risk factors. In the recent report by Stiebel-Kalish et al [2] describing 11 patients who were treated with Guglielmi detachable coils, complete resolution of TNP did not occur in any of the 11 cases. However, residual third nerve deficits did not cause diplopia with primary gaze for 10 of 11 patients. The pupil remained minimally affected in all cases. Additionally, the authors made the point that older age and the presence of microvascular risk factors (smoking, diabetes mellitus, and hypertension) seem to be detrimental to TNP recovery. There is enough heterogeneity of case types and disease severity and also marked differences in the assessment of recovery among these different series. We agree that further randomized controlled studies are needed to investigate the microvascular risk factors for prognosis of TNP. Additionally, our study design has some limitations. The lack of a statistically significant difference might be due to equivalence of these two techniques, but it is more likely due to a difference in benefits detected with little power in only 17 patients. Since our study only involves 17 patients, of whom 7 underwent clipping and 10 coil embolization, the numbers are too small to detect a difference should a difference exist (Type II error). Patients were not randomized to the different treatments and there is no explanation in the test as to why one treatment was selected rather that the other. A large randomized study will be needed to verify equivalence or detect a difference in benefits of these techniques. The collaboration among the practitioner from this multidisciplinary service demonstrates the type of prospective information that can be gathered. References 1. Ahn JY, Han IB, Yoon PH, et al. Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy. Neurology 2006;66:121-123. 2. Stiebel-Kalish H, Maimon S, Amsalem J, Erlich R, Kalish Y, Rappaport HZ. Evolution of oculomotor nerve paresis after endovascular coiling of posterior communicating artery aneurysms: a neuro-ophthalmological perspective. Neurosurgery 2003;53:1268-1273. Disclosure: The authors report no conflicts of interest.