{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T03:15:38Z","timestamp":1789960538017,"version":"4.0.1"},"reference-count":35,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,10]],"date-time":"2026-01-10T00:00:00Z","timestamp":1768003200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Objectives: To characterize the learning curve of endoscopic transsphenoidal pituitary adenoma surgery performed by a single neurosurgeon, assess how operative time, resection rates, and clinical outcomes evolved with experience, and identify tumor-related factors influencing surgical performance. Methods: This retrospective study included 123 consecutive endoscopic transsphenoidal pituitary adenoma resections performed between 2018 and 2025. Cases were divided into quartiles according to chronological order. Clinical, radiological, endocrinological, and operative variables were analyzed. Gross total resection (GTR), biochemical remission, postoperative complications, and visual and cranial nerve outcomes were compared between quartiles. A segmented linear regression model was applied to identify changepoints in the operative-time learning curve. Statistical significance was set at p &lt; 0.05. Results: The mean operative time decreased by 31.8%, from 160.8 min in Quartile 1 to 109.7 min in Quartile 4. Segmented regression revealed two changepoints at cases 47 and 85, defining three learning phases: a steep improvement phase, a consolidation phase, and a plateau. GTR was achieved in 51.2% of patients and did not significantly differ across quartiles. For Knosp 0\u20132 tumors, GTR was 76.1% overall; for Knosp 3\u20134 tumors, 30%. Tumor diameter, Knosp grade, and sphenoid sinus invasion were strongly associated with lower GTR rates (all p &lt; 0.05). Biochemical remission was achieved in 74.2% of patients with functional adenomas. New or worsened postoperative pituitary insufficiency significantly decreased across quartiles (p &lt; 0.001). Rates of postoperative diabetes insipidus (30.8%) and CSF leak (6.5%) were comparable with published literature and showed no consistent temporal trend. Conclusions: A clear learning curve exists in endoscopic pituitary surgery, with operative proficiency achieved after approximately 50 cases and an experienced plateau after ~90 cases. Surgical experience significantly reduced operative time and postoperative pituitary insufficiency but did not influence GTR rates, likely due to a high and increasing proportion of large tumors with cavernous sinus invasion. Tumor size, Knosp grade, and sphenoid sinus invasion were identified as major determinants of surgical complexity and should be accounted for when evaluating learning curves and surgical outcomes.<\/jats:p>","DOI":"10.3390\/jcm15020569","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T08:20:37Z","timestamp":1768206037000},"page":"569","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Learning Curve in Endoscopic Pituitary Surgery: Is Progress over Time Always Guaranteed? A Consecutive Series of 123 Cases from a Single Center"],"prefix":"10.3390","volume":"15","author":[{"given":"Marta","family":"Ko\u017aba-Goszty\u0142a","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Wroclaw 4th Military Clinical Hospital, 50-981 Wroclaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anastasija","family":"Krzemi\u0144ska","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Wroclaw 4th Military Clinical Hospital, 50-981 Wroclaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-4047-9922","authenticated-orcid":false,"given":"Tomasz","family":"Szczepa\u0144ski","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Wroclaw 4th Military Clinical Hospital, 50-981 Wroclaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bogdan","family":"Czapiga","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Wroclaw 4th Military Clinical Hospital, 50-981 Wroclaw, Poland"},{"name":"Faculty of Medicine, Wroclaw University of Science and Technology, Grunwaldzki Square 11, 51-377 Wroc\u0142aw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1096","DOI":"10.3171\/jns.2005.103.6.1096","article-title":"Harvey Cushing and Oskar Hirsch: Early forefathers of modern transsphenoidal surgery","volume":"103","author":"Liu","year":"2005","journal-title":"J. Neurosurg."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.wneu.2016.09.120","article-title":"Endoscopic Versus Microscopic Transsphenoidal Approach for Pituitary Adenomas: Comparison of Outcomes During the Transition of Methods of a Single Surgeon","volume":"97","author":"Eseonu","year":"2017","journal-title":"World Neurosurg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"E3","DOI":"10.3171\/foc.2005.19.6.4","article-title":"Brief history of endoscopic transsphenoidal surgery--from Philipp Bozzini to the First World Congress of Endoscopic Skull Base Surgery","volume":"19","author":"Doglietto","year":"2005","journal-title":"Neurosurg. Focus"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1288\/00005537-199202000-00016","article-title":"Endoscopic pituitary tumor surgery","volume":"102","author":"Jankowski","year":"1992","journal-title":"Laryngoscope"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1292","DOI":"10.1002\/lary.20949","article-title":"Microscopic versus endoscopic pituitary surgery: A systematic review","volume":"120","author":"Rotenberg","year":"2010","journal-title":"Laryngoscope"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1007\/s10143-025-03600-3","article-title":"Safety and efficacy of endoscopic vs. microscopic approaches in pituitary adenoma surgery: A systematic review and meta-analysis","volume":"48","author":"Khaity","year":"2025","journal-title":"Neurosurg. Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1007\/s10143-023-02136-8","article-title":"The learning curve for endoscopic endonasal pituitary surgery: A systematic review","volume":"46","author":"Candy","year":"2023","journal-title":"Neurosurg. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2361","DOI":"10.1007\/s00701-020-04471-x","article-title":"The slope of the learning curve in 600 consecutive endoscopic transsphenoidal pituitary surgeries","volume":"162","author":"Younus","year":"2020","journal-title":"Acta Neurochir."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"750","DOI":"10.3171\/2019.12.JNS192600","article-title":"How long is the tail end of the learning curve? Results from 1000 consecutive endoscopic endonasal skull base cases following the initial 200 cases","volume":"134","author":"Younus","year":"2020","journal-title":"J. Neurosurg."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Huang, J., Hong, X., Cai, Z., Lv, Q., Jiang, Y., Dai, W., Hu, G., Yan, Y., Chen, J., and Ding, X. (2023). The learning curve of endoscopic endonasal transsphenoidal surgery for pituitary adenomas with different surgical complexity. Front. Surg., 10.","DOI":"10.3389\/fsurg.2023.1117766"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1205","DOI":"10.1227\/NEU.0b013e3181ef25c5","article-title":"Endoscopic transsphenoidal pituitary surgery: Evidence of an operative learning curve","volume":"67","author":"Leach","year":"2010","journal-title":"Neurosurgery"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1080\/02688697.2016.1199786","article-title":"Learning curve for the transsphenoidal endoscopic endonasal approach to pituitary tumors","volume":"30","author":"Qureshi","year":"2016","journal-title":"Br. J. Neurosurg."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1093\/ons\/opx110","article-title":"Three-Hand Endoscopic Endonasal Transsphenoidal Surgery: Experience with an Anatomy-Preserving Mononostril Approach Technique","volume":"14","author":"Eseonu","year":"2018","journal-title":"Oper. Neurosurg."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/j.jocn.2017.09.011","article-title":"Learning curve of endoscopic pituitary surgery: Experience of a neurosurgery\/ENT collaboration","volume":"47","author":"Lofrese","year":"2018","journal-title":"J. Clin. Neurosci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1055\/s-0029-1238214","article-title":"Light at the end of the tunnel: The learning curve associated with endoscopic transsphenoidal skull base surgery","volume":"20","author":"Smith","year":"2010","journal-title":"Skull Base"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"E7","DOI":"10.3171\/foc.2005.19.1.8","article-title":"Endoneurosurgical hemostasis techniques: Lessons learned from 400 cases","volume":"19","author":"Kassam","year":"2005","journal-title":"Neurosurg. Focus"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2064","DOI":"10.1097\/SCS.0b013e3182a24328","article-title":"A learning curve of endoscopic transsphenoidal surgery for pituitary adenoma","volume":"24","author":"Chi","year":"2013","journal-title":"J. Craniofac. Surg."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"E10","DOI":"10.3171\/FOC.2008.25.12.E10","article-title":"Comparison of endoscopic and microscopic removal of pituitary adenomas: Single-surgeon experience and the learning curve","volume":"25","author":"Grady","year":"2008","journal-title":"Neurosurg. Focus"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"608","DOI":"10.1016\/j.wneu.2017.03.008","article-title":"Operative Learning Curve After Transition to Endoscopic Transsphenoidal Pituitary Surgery","volume":"102","author":"Shikary","year":"2017","journal-title":"World Neurosurg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1270","DOI":"10.1007\/s00464-014-3815-0","article-title":"Endoscopic endonasal transsphenoidal surgery of 1166 pituitary adenomas","volume":"29","author":"Wang","year":"2015","journal-title":"Surg. Endosc."},{"key":"ref_21","first-page":"1006","article-title":"Pure endoscopic endonasal approach for pituitaryadenomas: Early surgical results in 200 patientsand comparison with previous microsurgical series","volume":"62","author":"Dehdashti","year":"2008","journal-title":"Neurosurgery"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1007\/s11102-009-0195-x","article-title":"Endoscopic endonasal transsphenoidal surgery: Surgical results of 228 pituitary adenomas treated in a pituitary center","volume":"13","author":"Gondim","year":"2010","journal-title":"Pituitary"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1227\/01.NEU.0000137330.02549.0D","article-title":"Endoscopic endonasal transsphenoidal surgery","volume":"55","author":"Cappabianca","year":"2004","journal-title":"Neurosurgery"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1007\/s10143-006-0033-9","article-title":"The learning curve in endoscopic pituitary surgery and our experience","volume":"29","author":"Koc","year":"2006","journal-title":"Neurosurg. Rev."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Boetto, J., Joitescu, I., Raingeard, I., Ng, S., Le Corre, M., Lonjon, N., Crampette, L., and Favier, V. (2022). Endoscopic transsphenoidal surgery for non-functioning pituitary adenoma: Learning curve and surgical results in a prospective series during initial experience. Front. Surg., 9.","DOI":"10.3389\/fsurg.2022.959440"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"44","DOI":"10.3109\/02688697.2012.709554","article-title":"Endoscopic transsphenoidal pituitary surgery: A single surgeon experience and the learning curve","volume":"27","author":"Bokhari","year":"2013","journal-title":"Br. J. Neurosurg."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Shou, X., Shen, M., Zhang, Q., Zhang, Y., He, W., Ma, Z., Zhao, Y., Li, S., and Wang, Y. (2016). Endoscopic endonasal pituitary adenomas surgery: The surgical experience of 178 consecutive patients and learning curve of two neurosurgeons. BMC Neurol., 16.","DOI":"10.1186\/s12883-016-0767-0"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e409","DOI":"10.1016\/j.wneu.2017.09.194","article-title":"Endoscopic Transsphenoidal Surgery Outcomes in 331 Nonfunctioning Pituitary Adenoma Cases After a Single Surgeon Learning Curve","volume":"109","author":"Kim","year":"2018","journal-title":"World Neurosurg."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.clineuro.2008.09.010","article-title":"Predictors of short term outcomes following endoscopic pituitary surgery","volume":"111","author":"Tabaee","year":"2009","journal-title":"Clin. Neurol. Neurosurg."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"894","DOI":"10.1210\/jc.2010-1048","article-title":"Endocrine Society Pituitary incidentaloma: An endocrine society clinical practice guideline","volume":"96","author":"Freda","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1046\/j.1365-2265.1998.00581.x","article-title":"The outcome of surgery for acromegaly: The need for a specialist pituitary surgeon for all types of growth hormone (GH) secreting adenoma","volume":"49","author":"Lissett","year":"1998","journal-title":"Clin. Endocrinol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1136\/jnnp.2004.035576","article-title":"The time course of visual field recovery following transphenoidal surgery for pituitary adenomas: Predictive factors for a good outcome","volume":"76","author":"Gnanalingham","year":"2005","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1016\/S0002-9394(00)00539-0","article-title":"Stages of improvement in visual fields after pituitary tumor resection","volume":"130","author":"Kerrison","year":"2000","journal-title":"Am. J. Ophthalmol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2245","DOI":"10.1007\/s10143-020-01408-x","article-title":"Visual acuity and its postoperative outcome after transsphenoidal adenoma resection","volume":"44","author":"Butenschoen","year":"2021","journal-title":"Neurosurg. Rev."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"7966","DOI":"10.1167\/iovs.11-7450","article-title":"The time course of visual field recovery and changes of retinal ganglion cells after optic chiasmal decompression","volume":"52","author":"Moon","year":"2011","journal-title":"Investig. Ophthalmol. Vis. Sci."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/2\/569\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T08:35:04Z","timestamp":1768206904000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/2\/569"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,10]]},"references-count":35,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["jcm15020569"],"URL":"https:\/\/doi.org\/10.3390\/jcm15020569","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,10]]}}}