To the Editor: We appreciate the letter to the editor submitted by Dr Erdem1 regarding our recent video publication entitled The Paramedian Supracerebellar Transtentorial Selective Amygdalohippocampectomy for Mediobasal Temporal Epilepsy.2 We are thankful for his constructive comments, and in this letter we try to address some of his concerns. First, we would like to clarify that the selective amygdalohippocampectomy (SAH) for temporal lobe epilepsy was first described by Niemeyer in 1958,3 and Yaşargil described his novel surgical technique of SAH, the pterional transsylvian SAH, in 1982.4 Since then, various surgical techniques have been described for SAH, and only some are referred to here.3,5-25 New approaches and surgical techniques should be appreciated and encouraged by the neurosurgical community as key for improvement. Thorough evaluation of their efficacy and risks, as well as the appropriateness for certain surgical targets, should be objectively discussed. Before switching to the paramedian supracerebellar-transtentorial selective amygdalohippocampectomy (PST-SAH), the senior author (U.T.) used the pterional-transsylvian SAH for years and achieved good results in controlling seizures with favorable neuropsychological outcomes. After extensive cadaveric studies and further experience, we employed the PST approach for tumors involving the entire mediobasal temporal region (MTR).26 With the PST approach, it became possible to remove these lesions in 1 session instead of combining the pterional-transsylvian and posterior interhemispheric approaches. Our first cases showed that there was more to this approach. Access was exceptional for selective removal of the amygdala and hippocampus. Especially, the posterior portion of the hippocampus, which was difficult to reach through the pterional-transsylvian approach, was then within easy reach of the surgeon. The amygdala could be totally exposed for total removal, which is not possible with other approaches. We performed the PST-SAH on 6 patients with mediobasal temporal epilepsy (MTE) due to hippocampal sclerosis, and published the results with 9 other cases of MTR lesions in 2012.26 In this total of 15 cases, there was no mortality or morbidity. In all 6 patients with MTE, selective complete removal of the parahippocampal gyrus, hippocampus, and amygdala was successful, and all of these patients’ antiepileptic drugs could be gradually decreased to 1 by the time of the publication.26 As of the date of this letter, we have not been notified of any seizure activity, and in 3 of these patients we gradually discontinued the antiepileptic medication while the other 3 continue using a low dose of one antiepileptic drug. Postoperative visual fields remained intact in all patients. To date, 30 patients have undergone PST-SAH and the results of our series are being prepared for peer-reviewed publication. A total of 60 patients with MTR lesions and hippocampal sclerosis underwent surgery via the PST approach without any morbidity or mortality. Interestingly, in most of PST-SAH surgeries, Professor Yaşargil was in the operating theater and his suggestions and encouragement contributed enormously to the development of the PST-SAH. He accepted this technique as a viable alternative to pterional-transsylvian SAH, and also mentioned it in his manuscript.27 The effectiveness of the PST approach has been demonstrated in video publications, including removal of a posterior fusiform gyrus arteriovenous malformation28 and a tentorial incisura meningioma.29 At first, the PST approach might seem challenging, but once the surgeon adapts to this different anatomical perspective, the PST approach will prove its feasibility, especially in patients with lower tentorial angle.30 This surgical technique offers various landmarks throughout the procedure that help navigation within the MTR safely. We believe that new generations will accept and use this surgical technique with all its advantages. In conclusion, providing a safe and direct route medial to the collateral sulcus, away from the temporal neocortical structures and visual pathways, the PST-SAH offers a real as well as complete selective amygdalohippocampectomy for hippocampal sclerosis. This approach brings an end to the discussion about the visual field in epilepsy surgery. Moreover, leaving the neocortical temporal structures intact helps prevent postoperative iatrogenic seizures. Once again, we would like to express our gratitude to Dr Erdem for his interest in the PST approach. Disclosure The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this manuscript. REFERENCES 1. Erdem A. Letter: the paramedian supracerebellar-transtentorial selective amygdalohippocampectomy for mediobasal temporal epilepsy. Oper Neurosurg . 2018. doi: 10.1093/ons/opy084. [Published online ahead of print]. 2. Harput MV, Türe U. The paramedian supracerebellar- transtentorial selective amygdalohippocampectomy for mediobasal temporal epilepsy. Oper Neurosurg . 2017; 14( 4): 462. Google Scholar CrossRef Search ADS 3. Niemeyer P. The transventricular amygdala-hippocampectomy in temporal lobe epilepsy. In: Baldwin M, Bailey P, eds. The Temporal Lobe Epilepsy . Springfield, IL: Charles C Thomas; 1958: 461- 482. 4. Wieser HG, Yasargil MG. Selective amygdalohippocampectomy as a surgical treatment of mesiobasal limbic epilepsy. Surg Neurol . 1982; 17( 6): 445- 457. Google Scholar CrossRef Search ADS PubMed 5. Bahuleyan B, Fisher W, Robinson S, Cohen AR. Endoscopic transventricular selective amygdalohippocampectomy: cadaveric demonstration of a new operative approach. World Neurosurg . 2013; 80( 1-2): 178- 182. Google Scholar CrossRef Search ADS PubMed 6. Chen HI, Bohman LE, Loevner LA, Lucas TH. Transorbital endoscopic amygdalohippocampectomy: a feasibility investigation. J Neurosurg . 2014; 120( 6): 1428- 1436. Google Scholar CrossRef Search ADS PubMed 7. Delev D, Schramm J, Clusmann H. How I do it - selective amygdalohippocampectomy via a navigated temporobasal approach, when veins forbid elevation of the temporal lobe. Acta Neurochir . 2018; 160( 3): 597- 601. Google Scholar CrossRef Search ADS PubMed 8. Figueiredo EG, Deshmukh P, Nakaji P et al. Anterior selective amygdalohippocampectomy: technical description and microsurgical anatomy. Neurosurgery . 2010; 66( 3 Suppl Operative): 45- 53. Google Scholar PubMed 9. Flores JAC, Sanders FH, Figueiredo EG, Teixeira MJ. Transtemporal amygdalohippocampectomy: a novel minimally-invasive technique with optimal clinical results and low cost. Arq Neuropsiquiatr . 2017; 75( 11): 801- 808. Google Scholar CrossRef Search ADS PubMed 10. Ghizoni E, Matias RN, Lieber S et al. Clinical and imaging evaluation of transuncus selective amygdalohippocampectomy. World Neurosurg . 2017; 100: 665- 674. Google Scholar CrossRef Search ADS PubMed 11. Holanda VM, Gungor A, Baydin S, Middlebrooks EH, Danish SF. Anatomic investigation of the trajectory for stereotactic laser amygdalohippocampectomy. Oper Neurosurg (Hagerstown) . 2017. doi: 10.1093/ons/opx218. [Published online ahead of print]. 12. Hori T, Kondo S, Takenobu A et al. Retrolabyrinthine presigmoid transpetrosal approach for selective subtemporal amygdalohippocampectomy. Neurol Med Chir (Tokyo) . 1999; 39( 3): 214- 225. Google Scholar CrossRef Search ADS PubMed 13. Hori T, Tabuchi S, Kurosaki M, Kondo S, Takenobu A, Watanabe T. Subtemporal amygdalohippocampectomy for treating medically intractable temporal lobe epilepsy. Neurosurgery . 1993; 33( 1): 50- 56. Google Scholar PubMed 14. Kalina M, Lisck R, Vojtech Z et al. Stereotactic amygdalohippocampectomy for temporal lobe epilepsy: promising results in 16 patients. Epileptic Disord . 2007; 9( suppl 1): S68- S74. Google Scholar PubMed 15. Kalinin P, Sharipov O, Kutin M et al. Amygdalohippocampectomy via the lateral extended transsphenoidal endoscopic approach through the pterygopalatine fossa: An anatomic study. World Neurosurg . 2017; 103: 457- 464. Google Scholar CrossRef Search ADS PubMed 16. Kishima H, Kato A, Oshino S et al. Navigation-assisted trans-inferotemporal cortex selective amygdalohippocampectomy for mesial temporal lobe epilepsy; preserving the temporal stem. Neurol Res . 2017; 39( 3): 223- 230. Google Scholar CrossRef Search ADS PubMed 17. Kratimenos GP, Pell MF, Thomas DG, Shorvon SD, Fish DR, Smith SJ. Open stereotactic selective amygdalo-hippocampectomy for drug resistant epilepsy. Acta Neurochir . 1992; 116( 2-4): 150- 154. Google Scholar CrossRef Search ADS PubMed 18. Liscak R, Malikova H, Kalina M et al. Stereotactic radiofrequency amygdalohippocampectomy in the treatment of mesial temporal lobe epilepsy. Acta Neurochir . 2010; 152( 8): 1291- 1298. Google Scholar CrossRef Search ADS PubMed 19. Mandel M, Figueiredo EG, Mandel SA, Tutihashi R, Teixeira MJ. Minimally invasive transpalpebral endoscopic-assisted amygdalohippocampectomy. Oper Neurosurg (Hagerstown) . 2017; 13( 1): 2- 14. Google Scholar PubMed 20. Mathon B, Clemenceau S. Selective amygdalohippocampectomy via trans-superior temporal gyrus keyhole approach. Acta Neurochir . 2016; 158( 4): 785- 789. Google Scholar CrossRef Search ADS PubMed 21. Miyagi Y, Shima F, Ishido K et al. Inferior temporal sulcus approach for amygdalohippocampectomy guided by a laser beam of stereotactic navigator. Neurosurgery . 2003; 52( 5): 1117- 1123. Google Scholar PubMed 22. Nadvornik P, Sramka M, Gajdosova D, Kokavec M. Longitudinal hippocampectomy. A new stereotaxic approach to the gyrus hippocampi. Confin Neurol . 1975; 37( 1-3): 245- 248. Google Scholar CrossRef Search ADS PubMed 23. Park TS, Bourgeois BF, Silbergeld DL, Dodson WE. Subtemporal transparahippocampal amygdalohippocampectomy for surgical treatment of mesial temporal lobe epilepsy. J Neurosurg . 1996; 85( 6): 1172- 1176. Google Scholar CrossRef Search ADS PubMed 24. Schoenberg MR, Clifton WE, Sever RW, Vale FL. Neuropsychology outcomes following trephine epilepsy surgery: the inferior temporal gyrus approach for amygdalohippocampectomy in medically refractory mesial temporal lobe epilepsy. Neurosurgery . 2017. doi: 10.1093/neuros/nyx302. [Published online ahead of print]. 25. Wheatley BM. Selective amygdalohippocampectomy: the trans-middle temporal gyrus approach. Neurosurg Focus . 2008; 25( 3): E4. Google Scholar CrossRef Search ADS PubMed 26. Türe U, Harput MV, Kaya AH et al. The paramedian supracerebellar-transtentorial approach to the entire length of the mediobasal temporal region: an anatomical and clinical study. J Neurosurg . 2012; 116( 4): 773- 791. Google Scholar CrossRef Search ADS PubMed 27. Yasargil MG, Krayenbuhl N, Roth P, Hsu SP, Yasargil DC. The selective amygdalohippocampectomy for intractable temporal limbic seizures. J Neurosurg . 2010; 112( 1): 168- 185. Google Scholar CrossRef Search ADS PubMed 28. Harput MV, Türe U. The paramedian supracerebellar-transtentorial approach to remove a posterior fusiform gyrus arteriovenous malformation. Neurosurg Focus . 2017; 43( VideoSuppl1): V7. Google Scholar CrossRef Search ADS PubMed 29. Manilha R, Harput VM, Türe U. The paramedian supracerebellar-transtentorial approach for a tentorial incisura meningioma: 3-dimensional operative video. Oper Neurosurg (Hagerstown) . 2017. doi: 10.1093/ons/opx250. [Published online ahead of print]. 30. Lafazanos S, Türe U, Harput MV et al. Evaluating the importance of the tentorial angle in the paramedian supracerebellar-transtentorial approach for selective amygdalohippocampectomy. World Neurosurg . 2015; 83( 5): 836- 841. Google Scholar CrossRef Search ADS PubMed Acknowledgment The authors thank Julie Yamamoto for editing the narration and the abstract of the original article. Copyright © 2018 by the Congress of Neurological Surgeons
Operative Neurosurgery – Oxford University Press
Published: Apr 24, 2018
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