Abstract：Objective This study aimed to investigate the feasibility of observing the morphological characteristics of the cavum septum pellucidum (CSP) by magnetic resonance imaging (MRI) and determine whether the two leaves of the septum could be separated, which is important for optimizing the frontal interhemispheric approach through the CSP and vergae cavum septum pellucidum et vergae(CSPV) for corpus callosotomy.Methods A retrospective study was adopted. Thirty-one patients with medically intractable epilepsy, who underwent corpus callosotomy from January 2014 to December 2020 at the Department of Functional Neurosurgery, Shanghai Renji Hospital, were enrolled. Of the patients, 21 were males, and 10 were females, with a mean age of 2-31 (15.3±7.3) years. The course of their disease was 0.5-29 (10.0±6.5) years. Conventional MRI with 5.0 mm slices and/or high-resolution MRI with 1.0-2.0 mm slices was performed. The incidence of CSP was observed, and its morphological characteristics were studied using the imaging-based classification of CSP developed previously. The correlation between preoperative MRI results and intraoperative findings was investigated.Results (1) CSP was found on preoperative MRIs in 29 of 31 patients. Among them, 28 patients had CSP gap (type Ⅱ), and one had CSP cyst (type Ⅳ). In two patients with brain malformation, a CSP was not observed on MRI (type Ⅰ). (2) Intraoperatively, the CSP could be found, and the two leaves of the septum could be separated in 29 patients with visible CSP on preoperative MRIs. In one patient with CSP type Ⅳ, the CSPV could be easily reached when the corpus callosum was sectioned. For the remaining 28 patients with CSP type Ⅱ, the CSP could be reached, although the orientation of the CSP was difficult to reach in some patients. The two leaves of the septum could be easily separated once the CSP was opened. However, in two patients with CSP type Ⅰ, the separation of the leaves was impossible. Hence, a transventricular approach was adopted.Conclusions Preoperative MRI assessment of the CSP and its morphological features has a predictable effect, which is used as a radiological indicator to determine whether or not the leaves of the septum should be separated. In addition, it is used to assess the anticipated difficulty of surgical procedures and optimize surgical approaches for corpus callosotomy. Furthermore, patients with CSP type Ⅰ are not suitable for a frontal interhemispheric approach through the CSPV.
马军峰, 郭烈美, 王冉, 刘晓英, 张溥明, 周洪语. 经纵裂-透明隔间腔入路胼胝体切开术前对透明隔腔的MRI评估[J]. 中华解剖与临床杂志, 2021, 26(6): 605-609.
Ma Junfeng, Guo Liemei, Wang Ran, Liu Xiaoying, Zhang Puming, Zhou Hongyu. Frontal interhemispheric approach via the cavum septum pellucidum for corpus callosotomy-preoperative MRI evaluation. Chinese Journal of Anatomy and Clinics, 2021, 26(6): 605-609.
Zhou HY, Ma JF, Liu QQ, et al. Surgical methods and clinical outcomes of corpus callosotomy through longitudinal fissure-cavum septum pellucidum et vergae approach for refractory epilepsy[J]. Chin J Neurosurg, 2020, 36(4): 348-52. DOI:10.3760/cma.j.cn112050-20190530-00238.
[6]
Chan AY, Rolston JD, Lee B, et al. Rates and predictors of seizure outcome after corpus callosotomy for drug-resistant epilepsy: a meta-analysis[J]. J Neurosurg, 2019, 130(4): 1193-1202. DOI:10.3171/2017.12.JNS172331.
[7]
Graham D, Tisdall MM, Gill D. Corpus callosotomy outcomes in pediatric patients: a systematic review[J]. Epilepsia, 2016, 57(7): 1053-1068. DOI:10.1111/epi.13408.
[8]
Baba H, Toda K, Ono T, et al. Surgical and developmental outcomes of corpus callosotomy for West syndrome in patients without MRI lesions[J]. Epilepsia, 2018, 59(12): 2231-2239. DOI:10.1111/epi.14594.
[9]
Cukiert A, Burattini JA, Mariani PP, et al. Extended, one-stage callosal section for treatment of refractory secondarily generalized epilepsy in patients with Lennox-Gastaut and Lennox-like syndromes[J]. Epilepsia, 2006, 47(2): 371-374. DOI:10.1111/j.1528-1167.2006.00430.x.
[10]
Cukiert A, Burattini JA, Mariani PP, et al. Outcome after extended callosal section in patients with primary idiopathic generalized epilepsy[J]. Epilepsia, 2009, 50(6): 1377-80. DOI:10.1111/j.1528-1167.2008.01875.x.
[11]
Malmgren K, Rydenhag B, Hallböök T. Reappraisal of corpus callosotomy[J]. Curr Opin Neurol, 2015, 28(2): 175-181. DOI:10.1097/WCO.0000000000000179.
[12]
Stigsdotter-Broman L, Olsson I, et al. Long-term follow-up after callosotomy—a prospective, population based, observational study[J]. Epilepsia, 2014, 55(2): 316-321. DOI:10.1111/epi.12488.
Zhou HY, Ye XL, Ma JF, et al. MR imaging and anatomical study of cavum septum pellucidum et vergae[J]. Chin J Anat Clin, 2020, 25(2): 123-128. DOI:10.3760/cma.j.cn101202-20190530-00178.
[15]
Sarwar M. The septum pellucidum: normal and abnormal[J]. AJNR Am J Neuroradiol, 1989, 10(5): 989-1005.
[16]
Winkler PA, Weis S, Büttner A, et al. The transcallosal interforniceal approach to the third ventricle: anatomic and microsurgical aspects[J]. Neurosurgery, 1997, 40(5): 973-982. DOI:10.1097/00006123-199705000-00020.
Li GX, Wan WQ, Wang YH. Microsurgical anatomy of fornix and its application in surgery of transcallosal-interforniceal approach[J]. Chin J Neurosurg, 2014, 30(12): 1266-1270. DOI:10.3760/cma.j.issn.1001-2346.2014.12.022.
[18]
Shaw CM, Alvord EC Jr. Cava septi pellucidi et vergae: their normal and pathogical states[J]. Brain, 1969, 92(1): 213-223. DOI:10.1093/brain/92.1.213.
[19]
Tubbs RS, Krishnamurthy S, Verma K, et al. Cavum velum interpositum, cavum septum pellucidum, and cavum vergae: a review[J]. Childs Nerv Syst, 2011, 27(11): 1927-1930. DOI:10.1007/s00381-011-1457-2.
2021, Vol. 26 
