The Role of Hemosiderin Excision in Seizure Outcome in Cerebral Cavernous Malformation Surgery: A Systematic Review and Meta-Analysis

The T2-weighted image show a cavernous malformation as heterogeneous and “popcorn-like” with a mixed signal intensity core and a hypointense hemosiderin rim.

T2WI and T2* gradient echo show multiple cavernomas. Notice the popcorn appearance with peripheral rim of hemosiderin on the T2WI. The lesions are almost completely black on the gradient echo due to blooming artefacts. T2* and susceptibility weighted imaging (SWI) markedly increase the sensitivity of MRI to detect small cavernomas. The five black dots in the left cerebral hemisphere on the T2* are also cavernomas and are not visible on the T2WI.

Importance

In ten studies comparing extended hemosiderin excision with only lesion resection were identified by searching the English-language literature. Meta-analyses, subgroup analyses and sensitivity analysis were conducted to determine the association between hemosiderin excision and seizure outcome after surgery.

Patients who underwent extended surrounding hemosiderin excision could exhibit significantly improved seizure outcomes compared to patients without hemosiderin excision. However, further well-designed prospective multiple-center RCT studies are still needed 1).

Previous works showed that extent of resection and its surrounding hemosiderin rim were found to consistently correlate with a more favorable post-operative seizure-free outcome 2) 3).

Patients with short duration of epilepsy associated with cavernous malformations could benefit greatly from complete resection of hemosiderin rim and cavernous malformations 4).

High field intraoperative MRI imaging (iopMRI) and neuronavigation might play a crucial role to achieve both goals 5).

26 patients (14 female, 12 male, mean age 39·1 years, range: 17-63 years) with CM related epilepsy were identified. Eighteen patients suffered from drug resistant epilepsy (69·2%). Mean duration of epilepsy was 11·9 years in subjects with drug resistant epilepsy (n = 18) and 0·3 years in subjects presenting with first-time seizures (n = 8).

24 lesionectomies and two lesionectomies combined with extended temporal resections were performed.

Seven lesions were located extratemporally.

Complete CM removal was documented by postsurgical MRI in all patients. As direct consequence of iopMRI, refined surgery was necessary in 11·5% of patients to achieve complete cavernoma removal and in another 11·5% for complete resection of additional adjacent epileptogenic cortex. Removal of the hemosiderin rim was confirmed by iopMRI in 92% of patients. Two patients suffered from mild (7·7%) and one from moderate (3·8%) visual field deficits. Complete seizure control (Engel class 1A) was achieved in 80·8% of patients with a mean follow-up period of 47·7 months 6).

1) Ruan D, Yu XB, Shrestha S, Wang L, Chen G. The Role of Hemosiderin Excision in Seizure Outcome in Cerebral Cavernous Malformation Surgery: A Systematic Review and Meta-Analysis. PLoS One. 2015 Aug 25;10(8):e0136619. doi: 10.1371/journal.pone.0136619. eCollection 2015. PubMed PMID: 26305879.
2) Stavrou I, Baumgartner C, Frischer JM, Trattnig S, Knosp E. Long-term seizure control after resection of supratentorial cavernomas: a retrospective single-center study in 53 patients. Neurosurgery. 2008 Nov;63(5):888-96; discussion 897. doi: 10.1227/01.NEU.0000327881.72964.6E. PubMed PMID: 19005379.
3) Kim W, Stramotas S, Choy W, Dye J, Nagasawa D, Yang I. Prognostic factors for post-operative seizure outcomes after cavernous malformation treatment. J Clin Neurosci. 2011 Jul;18(7):877-80. doi: 10.1016/j.jocn.2010.12.008. Epub 2011 May 10. Review. PubMed PMID: 21561775.
4) Jin Y, Zhao C, Zhang S, Zhang X, Qiu Y, Jiang J. Seizure outcome after surgical resection of supratentorial cavernous malformations plus hemosiderin rim in patients with short duration of epilepsy. Clin Neurol Neurosurg. 2014 Apr;119:59-63. doi: 10.1016/j.clineuro.2014.01.013. Epub 2014 Jan 25. PubMed PMID: 24635927.
5) Xie HW, Wang DM, Yuan QG, Sha C, Yang YM, Jiang HZ. [The utility of neuronavigation in the microsurgery for cerebral cavernous malformations]. Zhonghua Wai Ke Za Zhi. 2011 Aug 1;49(8):712-5. Chinese. PubMed PMID: 22168935.
6) Sommer B, Kasper BS, Coras R, Blumcke I, Hamer HM, Buchfelder M, Roessler K. Surgical management of epilepsy due to cerebral cavernomas using neuronavigation and intraoperative MR imaging. Neurol Res. 2013 Oct 23:0. [Epub ahead of print] PubMed PMID: 24070413.

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