{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:57:29Z","timestamp":1760151449508,"version":"build-2065373602"},"reference-count":21,"publisher":"Georg Thieme Verlag KG","issue":"06","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurol Surg A Cent Eur Neurosurg"],"published-print":{"date-parts":[[2025,11]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Most studies on Chiari malformation (CM) are focused on CM Type-1. A new subtype, CM Type-1.5, lacks sufficient research. This study aims to evaluate the long-term surgical outcomes of posterior fossa decompression followed by duraplasty with arachnoid-preserving (PFDD-AP) technique for primary and recurrent CM Type-1.5.<\/jats:p><jats:p>The medical charts of patients treated surgically for CM at our institute between January 2011 and January 2022 were reviewed retrospectively. Adult patients consecutively treated for CM Type-1.5 were selected as the core sample for the current study. Group A included primary cases (i.e., patients who had not previously been surgically treated), and Group B included recurrent cases. The surgical outcomes were compared by evaluating clinical and radiological findings.<\/jats:p><jats:p>Thirty-four CM Type-1.5 cases out of 202 CM cases met the study criteria. Twenty-three and 11 cases represented Group A and Group B, respectively. The female-to-male ratio was 2\/1. In Group B, the preoperative herniated tonsil extension and the obex position were statistically significantly longer, and retroversion and retroflexion angles were statistically considerably smaller ([p\u2009=\u20090.024; Z\u2009=\u2009\u2212\u20092.26]; [p\u2009=\u20090.023; Z\u2009=\u2009\u2212\u20092.27]; [p\u2009=\u20090.031; Z\u2009=\u2009\u2212\u20092.29]; and [p\u2009=\u20090.0002; Z\u2009=\u2009\u2212\u20093.72], respectively). For the cases presented with syringomyelia (SM) in both groups (n\u2009=\u200920), total and partial regression were recorded postoperatively in 65% and 15% of cases, respectively. The satisfactory recovery or improvement rate in neurological symptoms was 94.1%.<\/jats:p><jats:p>Total or partial SM regression occurred following PFDD-AP in most adult patients with CM Type-1.5 who presented with SM. The PFDD-AP approach offers better results with fewer complications and recurrence rates.<\/jats:p>","DOI":"10.1055\/a-2590-6183","type":"journal-article","created":{"date-parts":[[2025,6,26]],"date-time":"2025-06-26T18:50:15Z","timestamp":1750963815000},"page":"562-573","source":"Crossref","is-referenced-by-count":0,"title":["Posterior Fossa Decompression Followed by Duraplasty with Arachnoid-Preserving Technique for Primary and Recurrent Adult Chiari Malformation Type-1.5: A Comparative Retrospective Study"],"prefix":"10.1055","volume":"86","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7754-4984","authenticated-orcid":false,"given":"H\u00fcseyin","family":"Do\u011fu","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Istanbul Atlas University, Medical Faculty Hospital, Ba\u011fc\u0131lar, Istanbul, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3600-089X","authenticated-orcid":false,"given":"Anas","family":"Abdallah","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Istanbul Atlas University, Medical Faculty Hospital, Ba\u011fc\u0131lar, Istanbul, Turkey"},{"name":"Department of Neurosurgery, \u00dcsk\u00fcdar University, Medical Faculty, \u00dcsk\u00fcdar, Istanbul, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9390-7730","authenticated-orcid":false,"given":"Hidayet","family":"Akdemir","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Istanbul Atlas University, Medical Faculty Hospital, Ba\u011fc\u0131lar, Istanbul, 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