Introduction: Colloid cysts are histologically benign epithelial-lined tumors typically found posterior to the foramen of Monro in the roof of the third ventricle. Transcallosal microscopic and endoscopic excision are both well established approaches for this lesion; however, there has been no clear consensus regarding the favored approach. Here, we performed a meta-analysis comparing the two approaches for colloid cyst excision.

Methods: We performed a meta-analysis from 2000-2018 of patients undergoing colloid cyst excision via a microscopic transcallosal or endoscopic approach where complete excision of the cyst wall and its contents was the surgical intent. Studies that included head to head comparison of approaches were included if the reported results were stratified by approach.

Results: Overall, the microsurgical transcallosal approach had a higher rate of gross total resection when compared to endoscopic excision (96% for transcallosal vs 80% endoscopic; p<0.0001). There was also a lower recurrence rate with the transcallosal approach (0.98% vs 2.16%; p=0.0036), however, there was no difference in reoperation rates with similar length of follow-up (0.33% transcallosal, 0.61% endoscopic; p=1.000). Endoscopy had lower overall morbidity rates when compared to transcallosal approaches (7.9% vs 16.3%; p=0.0046), including statistically significant lower rates of infection, infarct, and seizures in the endoscopic cohort. Rates of permanent memory deficit were similar (6.3% transcallosal vs 4.6% endoscopic; p=0.244). Finally, shunt dependency was 9.8% after transcallosal excision vs 3.5% after endoscopic excision, a difference that was statistically significant (p=0.0002).

Conclusions: Modern series of colloid cyst excision continue to favor transcallosal approaches in achieving gross total resection. However, endoscopic techniques have significantly reduced morbidity compared to transcallosal approaches, including lower rates of infection, infarct and seizure. Endoscopic approaches also have a statistically significant decreased rate of shunt dependency, arguably the most important primary endpoint of surgery. With improving endoscopic technology and mastery of the technique, endoscopic excision is maturing into the standard first-line approach for colloid cyst excision.

Patient Care: This is a meta-analysis comparing transcallosal vs endoscopic colloid cyst excision. Many patients still have their colloid cysts removed via both approaches, although endoscopic excision has lower morbidity and lower rates of shunt dependency. The referral of colloid cyst patients to centers with providers trained at endoscopic excision will improve patient outcomes without increasing reoperation rates, despite a slightly higher recurrence rate that does not appear to be clinically significant.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of approach to colloid cyst excision rate and morbidity, 2) Discuss the risks and benefits of various approaches for colloid cyst excision, and 3) Identify an effective treatment strategy for colloid cyst excision based on individual patient risk factors and desired outcome.

References: 1. Grondin RT1, Hader W, MacRae ME, Hamilton MG. Endoscopic versus microsurgical resection of third ventricle colloid cysts. Can J Neurol Sci. 2007 May;34(2):197-207. 2. Shapiro S1, Rodgers R, Shah M, Fulkerson D, Campbell RL. Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle. J Neurosurg. 2009 Jan;110(1):112-5. 3. Chibbaro S1, Champeaux C, Poczos P, Cardarelli M, Di Rocco F, Iaccarino C, Servadei F, Tigan L, Chaussemy D, George B, Froelich S, Kehrli P, Romano A. Anterior trans-frontal endoscopic management of colloid cyst: an effective, safe, and elegant way of treatment. Case series and technical note from a multicenter prospective study. Neurosurg Rev. 2014 Apr;37(2):235-41. 4. Sribnick EA1, Dadashev VY1, Miller BA1, Hawkins S1, Hadjipanayis CG2. Neuroendoscopic colloid cyst resection: a case cohort with follow-up and patient satisfaction. World Neurosurg. 2014 Mar-Apr;81(3-4):584-93. 5. Sharifi G1, Bakhtevari MH2, Samadian M1, Alavi E1, Rezaei O1. Endoscopic Surgery in Nonhydrocephalous Third Ventricular Colloid Cysts: A Feasibility Study. World Neurosurg. 2015 Aug;84(2):398-404. 6. Osorio JA1, Clark AJ1, Safaee M1, Tate MC2, Aghi MK1, Parsa A1, McDermott MW3. Intraoperative Conversion from Endoscopic to Open Transcortical-Transventricular Removal of Colloid Cysts as a Salvage Procedure. Cureus. 2015 Feb 2;7(2):e247. 7. Birski M1, Birska J2, Paczkowski D2, Furtak J2, Rusinek M2, Rudas M2, Harat M2. Combination of Neuroendoscopic and Stereotactic Procedures for Total Resection of Colloid Cysts with Favorable Neurological and Cognitive Outcomes. World Neurosurg. 2016 Jan;85:205-14. Epub 2015 Sep 5. 8. Wait SD1, Gazzeri R, Wilson DA, Abla AA, Nakaji P, Teo C. Endoscopic colloid cyst resection in the absence of ventriculomegaly. Neurosurgery. 2013 Sep;73(1 Suppl Operative):ons39-46; ons46-7. 9. Yadav YR1, Parihar V1, Pande S2, Namdev H1. Endoscopic management of colloid cysts. J Neurol Surg A Cent Eur Neurosurg. 2014 Sep;75(5):376-80. 10. Margetis K1, Christos PJ, Souweidane M. Endoscopic resection of incidental colloid cysts. J Neurosurg. 2014 Jun;120(6):1259-67. 11. Levine NB1, Miller MN, Crone KR. Endoscopic resection of colloid cysts: indications, technique, and results during a 13-year period. Minim Invasive Neurosurg. 2007 Dec;50(6):313-7. 12. Greenlee JD1, Teo C, Ghahreman A, Kwok B. Purely endoscopic resection of colloid cysts. Neurosurgery. 2008 Mar;62(3 Suppl 1):51-5; discussion 55-6. 13. Engh JA1, Lunsford LD, Amin DV, Ochalski PG, Fernandez-Miranda J, Prevedello DM, Kassam AB. Stereotactically guided endoscopic port surgery for intraventricular tumor and colloid cyst resection. Neurosurgery. 2010 Sep;67(3 Suppl Operative):ons198-204; discussion ons204-5. 14. Harris AE1, Hadjipanayis CG, Lunsford LD, Lunsford AK, Kassam AB. Microsurgical removal of intraventricular lesions using endoscopic visualization and stereotactic guidance. Neurosurgery. 2005 Jan;56(1 Suppl):125-32; discussion 125-32. 15. Sampath R1, Vannemreddy P, Nanda A. Microsurgical excision of colloid cyst with favorable cognitive outcomes and short operative time and hospital stay: operative techniques and analyses of outcomes with review of previous studies. Neurosurgery. 2010 Feb;66(2):368-74; discussion 374-5. 16. Hoffman CE1, Savage NJ, Souweidane MM. The significance of cyst remnants after endoscopic colloid cyst resection: a retrospective clinical case series. Neurosurgery. 2013 Aug;73(2):233-7; discussion 237-9. 17. Horn EM1, Feiz-Erfan I, Bristol RE, Lekovic GP, Goslar PW, Smith KA, Nakaji P, Spetzler RF. Treatment options for third ventricular colloid cysts: comparison of open microsurgical versus endoscopic resection. Neurosurgery. 2008 Jun;62(6 Suppl 3):1076-83. 18. Wilson DA1, Fusco DJ, Wait SD, Nakaji P. Endoscopic resection of colloid cysts: use of a dual-instrument technique and an anterolateral approach. World Neurosurg. 2013 Nov; 80(5):576-83. 19. Hieronymus D. Boogaarts, MD* Philippe Decq, MD†?J. Andre ´ Grotenhuis, PhD, MD* Caroline Le Gue ´rinel, MD† Remi Nseir, PhD, MD† Be ´chir Jarraya, MD† Michel Djindjian, MD† Tjemme Beems, MD*. Long-term Results of the Neuroendoscopic Management of Colloid Cysts of the Third Ventricle: A Series of 90 Cases. Neurosurgery 68:179–187, 2011. 20. Ahmed B. Sheikh, Zachary S. Mendelson, James K. Liu. Endoscopic Versus Microsurgical Resection of Colloid Cysts: A Systematic Review and Meta-Analysis of 1278 Patients. World Neurosurg. (2014) 82, 6:1187-1197. 21. Azzazi A, AlMekawi S. Colloid Cysts of the Third Ventricle: Endoscopic versus Microsurgical Removal. Neurosurg Quart 20:142-145, 2010. 22. Ibanez-Botella G, Dominguez M, Ros B, de Miguel L, Marquez B, Arraez MA. Endoscopic Transchoroidal and Transforaminal Approaches for Resection of Third Ventricular Colloid Cysts. Neurosurg Rev 37:227-234, 2014. 23. Bergsneider M. Complete Microsurgical Resection of Colloid Cysts with a dual-port Endoscopic Technique. Neurosurgery 60:33-42; discussion 42-33, 2007. 24. Delitala A, Brunori A, Russo N. Supraorbital Endoscopic Approach to Colloid Cysts. Neurosurgery 69: 176-182; discussion 182-173, 2011. 25. Kwiek S, Kocur D, Dolezych H, Suszynski K, Szajkowski S, Sordyl R, Slusarczyk W, Kukier W, Bazowski P. Endoscopic Technique in the Treatment of Patients with Colloid Cysts of the Third Ventricle. Report based on over a decade of experience. Neurol Neurochir Pol 46:216-223, 2012. 26. Mishra S, Chandra PS, Suri A, Rajender K, Sharma BS, Mahapatra AK. Endoscopic Management of Third Ventricular Colloid Cysts: eight years’ institutional experience and description of a new technique. Neurol India 58:412-417, 2010. 27. Rodziewicz GS, Smith MV, Hodge CJ Jr. Endoscopic Colloid Cyst Surgery. Neurosurgery 46: 655-660; discussion 660-652, 2000. 28. Stachura K, Libionka W, Moskala M, Krupa M, Polak J. Colloid Cysts of the Third Ventricle. Endoscopic and Open Microsurgical Management. Neurol Neurochir Pol 43:251-257, 2009. 29. AggletonJP, McMackinD, CarpenterK, HornakJ, Kapur N, Halpin S, Wiles CM, Kamel H, Brennan P, Carton S, Gaffan D. Differential Cognitive Effects of Colloid Cysts in the Third Ventricle that Spare or Compromise the Fornix. Brain 123 (Pt 4):800-815, 2000. 30. Barlas O, Karadereler S. Stereotactically Guided Microsurgical Removal of Colloid Cysts. Acta Neurochir (Wien) 146:1199-1204, 2004. 31. Desai KI, Nadkarni TD, Muzumdar DP, Goel AH. Surgical Management of Colloid Cyst of the Third Ventricle—a study of 105 cases. Surg Neurol 57: 295-302; discussion 302-294, 2002. 32. Hernesniemi J, Romani R, Dashti R, Albayrak BS, Savolainen S, Ramsey C 3rd, Karatas A, Lehto H, Navratil O, Niemela M. Microsurgical Treatment of Third Ventricular Colloid Cysts by Interhemispheric Far Lateral Transcallosal Approach—experience of 134 patients. Surg Neurol 69:447-453; discussion 453-446, 2008. 33. Jeffree RL, Besser M. Colloid Cyst of the Third Ventricle: a clinical review of 39 cases. J Clin Neurosci 8:328-331, 2001. 34. Solaroglu I, Beskonakli E, Kaptanoglu E, Okutan O, Ak F, Taskin Y. Transcortical-Transventricular Approach in Colloid Cysts of the Third Ventricle: surgical experience with 26 cases. Neurosurg Rev 27:89-92, 2004. 35. Symss NP, Ramamurthi R, Rao SM, Vasudevan MC, Jain PK, Pande A. Management Outcome of the Transcallosal, Transforaminal Approach to Colloid Cysts of the Anterior Third Ventricle: an analysis of 78 cases. Neurol India 59: 542-547, 2011. 36. Pollock BE, Schreiner SA, Huston J III. A theory on the Natural History of Colloid Cysts of the Third Ventricle. Neurosurgery. 2000;46(5):1077-1081.