{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T01:05:43Z","timestamp":1779843943922,"version":"3.53.1"},"reference-count":16,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"21","license":[{"start":{"date-parts":[[2026,5,25]],"date-time":"2026-05-25T00:00:00Z","timestamp":1779667200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurosurg Case Lessons"],"published-print":{"date-parts":[[2026,5,25]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND<\/jats:title>\n                    <jats:p>Microvascular decompression (MVD) for trigeminal neuralgia (TN) caused by vertebrobasilar dolichoectasia (VBD) is technically challenging due to the vessel\u2019s size and stiffness. While ipsilateral abducens nerve (cranial nerve [CN] VI) palsy is a known complication, contralateral palsy resulting from force transmission remains unreported.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>OBSERVATIONS<\/jats:title>\n                    <jats:p>The authors describe 2 cases of CN VI palsy following MVD for VBD-associated TN. Case 1 developed ipsilateral palsy after caudal transposition of the vertebral artery, resulting from a paradoxical medial shift of the proximal vessel segment. Case 2 presented with a rare contralateral CN VI palsy. Postoperative imaging indicated that mobilizing the rigid VBD caused an \u201cen bloc\u201d shift of the entire vertebrobasilar system, resulting in secondary compression of the contralateral CN VI. Both patients achieved immediate pain relief, and the palsies recovered with conservative management.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>LESSONS<\/jats:title>\n                    <jats:p>Mobilizing a dolichoectatic VBD transmits mechanical force to distant segments via an en bloc shift, potentially injuring CN VI on either the operative or contralateral side. Preoperative identification of risk factors\u2014specifically severe calcification, preexisting contralateral deviation, and minimal contralateral CSF space\u2014is crucial. Surgeons should recognize that vascular transposition can transmit force bilaterally and must counsel patients regarding these risks.<\/jats:p>\n                    <jats:p>\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"https:\/\/thejns.org\/doi\/10.3171\/CASE2634\">https:\/\/thejns.org\/doi\/10.3171\/CASE2634<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/case2634","type":"journal-article","created":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T14:52:31Z","timestamp":1779288751000},"source":"Crossref","is-referenced-by-count":0,"title":["The \u201cen bloc\u201d shift: ipsilateral and contralateral abducens nerve palsy following microvascular decompression for trigeminal neuralgia caused by vertebrobasilar dolichoectasia. Illustrative cases"],"prefix":"10.3171","volume":"11","author":[{"given":"Shoko","family":"Ito","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0090-2747","authenticated-orcid":true,"given":"Kenzo","family":"Kosugi","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-4927-0195","authenticated-orcid":true,"given":"Hiroaki","family":"Fukumoto","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taichi","family":"Sayanagi","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Konosuke","family":"Ishikawa","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Narumi","family":"Watanabe","sequence":"additional","affiliation":[{"name":"Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takenori","family":"Akiyama","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2700-1620","authenticated-orcid":true,"given":"Masahiro","family":"Toda","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Keio University School of Medicine, Shinjuku-ku, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"4","key":"bib1","series-title":"Neurosurg Rev","first-page":"573","article-title":"Clinical analysis of trigeminal neuralgia caused by vertebrobasilar dolichoectasia","volume":"36","author":"Ma","year":"2013","unstructured":"Ma XSun XYao JClinical analysis of trigeminal neuralgia caused by vertebrobasilar dolichoectasia. Neurosurg Rev. 2013;36(4):573-577. doi:10.1007\/s10143-013-0468-8"},{"issue":"4","key":"bib2","series-title":"Acta Neurochir (Wien)","first-page":"1027","article-title":"Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia","volume":"163","author":"Inoue","year":"2021","unstructured":"Inoue TShitara SGoto YPrasetya MRadford JFukushima T.Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia. Acta Neurochir (Wien). 2021;163(4):1027-1036. doi:10.1007\/s00701-021-04742-1"},{"key":"bib3","series-title":"Surg Neurol Int","first-page":"242","article-title":"Microvascular decompression for abducens nerve palsy due to neurovascular compression from both the vertebral artery and anterior inferior cerebellar artery: a case report","volume":"11","author":"Miyamoto","year":"2020","unstructured":"Miyamoto SMatsuda MIshikawa EMatsumura A.Microvascular decompression for abducens nerve palsy due to neurovascular compression from both the vertebral artery and anterior inferior cerebellar artery: a case report. Surg Neurol Int. 2020;11:242. doi:10.25259\/SNI_94_2020"},{"issue":"6","key":"bib4","series-title":"Neurosurgery","first-page":"E1317","article-title":"Isolated abducent nerve palsy after microvascular decompression for trigeminal neuralgia: case report","volume":"57","author":"Choudhari","year":"2005","unstructured":"Choudhari KA.Isolated abducent nerve palsy after microvascular decompression for trigeminal neuralgia: case report. Neurosurgery. 2005;57(6):E1317. doi:10.1227\/01.neu.0000187451.24578.b4"},{"issue":"8","key":"bib5","series-title":"Clin Anat","first-page":"1030","article-title":"Microsurgical anatomy of the abducens nerve","volume":"25","author":"Joo","year":"2012","unstructured":"Joo WYoshioka FFunaki TRhoton ALJr.Microsurgical anatomy of the abducens nerve. Clin Anat. 2012;25(8):1030-1042. doi:10.1002\/ca.22047"},{"key":"bib6","series-title":"World Neurosurg","first-page":"454","article-title":"Aberrant abducent nerve during microvascular decompression for trigeminal neuralgia","volume":"138","author":"Borg","year":"2020","unstructured":"Borg AZrinzo L.Aberrant abducent nerve during microvascular decompression for trigeminal neuralgia. World Neurosurg. 2020;138:454-456. doi:10.1016\/j.wneu.2020.03.115"},{"issue":"2","key":"bib7","series-title":"Neurol India","first-page":"246","article-title":"Isolated abducens nerve palsy caused by contralateral vertebral artery dolichoectasia","volume":"53","author":"Giray","year":"2005","unstructured":"Giray SPelit AKizilkilic OKaratas M.Isolated abducens nerve palsy caused by contralateral vertebral artery dolichoectasia. Neurol India. 2005;53(2):246-247. doi:10.4103\/0028-3886.16433"},{"issue":"5","key":"bib8","series-title":"J Neurol Neurosurg Psychiatry","first-page":"679","article-title":"Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case","volume":"69","author":"Strauss","year":"2000","unstructured":"Strauss CNaraghi RBischoff BHuk WJRomst\u00f6ck J.Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case. J Neurol Neurosurg Psychiatry. 2000;69(5):679-682. doi:10.1136\/jnnp.69.5.679"},{"issue":"4","key":"bib1","series-title":"Neurosurg Rev","first-page":"573","article-title":"Clinical analysis of trigeminal neuralgia caused by vertebrobasilar dolichoectasia","volume":"36","author":"Ma","year":"2013","unstructured":"Ma XSun XYao JClinical analysis of trigeminal neuralgia caused by vertebrobasilar dolichoectasia. Neurosurg Rev. 2013;36(4):573-577. doi:10.1007\/s10143-013-0468-8"},{"issue":"4","key":"bib2","series-title":"Acta Neurochir (Wien)","first-page":"1027","article-title":"Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia","volume":"163","author":"Inoue","year":"2021","unstructured":"Inoue TShitara SGoto YPrasetya MRadford JFukushima T.Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia. Acta Neurochir (Wien). 2021;163(4):1027-1036. doi:10.1007\/s00701-021-04742-1"},{"key":"bib3","series-title":"Surg Neurol Int","first-page":"242","article-title":"Microvascular decompression for abducens nerve palsy due to neurovascular compression from both the vertebral artery and anterior inferior cerebellar artery: a case report","volume":"11","author":"Miyamoto","year":"2020","unstructured":"Miyamoto SMatsuda MIshikawa EMatsumura A.Microvascular decompression for abducens nerve palsy due to neurovascular compression from both the vertebral artery and anterior inferior cerebellar artery: a case report. Surg Neurol Int. 2020;11:242. doi:10.25259\/SNI_94_2020"},{"issue":"6","key":"bib4","series-title":"Neurosurgery","first-page":"E1317","article-title":"Isolated abducent nerve palsy after microvascular decompression for trigeminal neuralgia: case report","volume":"57","author":"Choudhari","year":"2005","unstructured":"Choudhari KA.Isolated abducent nerve palsy after microvascular decompression for trigeminal neuralgia: case report. Neurosurgery. 2005;57(6):E1317. doi:10.1227\/01.neu.0000187451.24578.b4"},{"issue":"8","key":"bib5","series-title":"Clin Anat","first-page":"1030","article-title":"Microsurgical anatomy of the abducens nerve","volume":"25","author":"Joo","year":"2012","unstructured":"Joo WYoshioka FFunaki TRhoton ALJr.Microsurgical anatomy of the abducens nerve. Clin Anat. 2012;25(8):1030-1042. doi:10.1002\/ca.22047"},{"key":"bib6","series-title":"World Neurosurg","first-page":"454","article-title":"Aberrant abducent nerve during microvascular decompression for trigeminal neuralgia","volume":"138","author":"Borg","year":"2020","unstructured":"Borg AZrinzo L.Aberrant abducent nerve during microvascular decompression for trigeminal neuralgia. World Neurosurg. 2020;138:454-456. doi:10.1016\/j.wneu.2020.03.115"},{"issue":"2","key":"bib7","series-title":"Neurol India","first-page":"246","article-title":"Isolated abducens nerve palsy caused by contralateral vertebral artery dolichoectasia","volume":"53","author":"Giray","year":"2005","unstructured":"Giray SPelit AKizilkilic OKaratas M.Isolated abducens nerve palsy caused by contralateral vertebral artery dolichoectasia. Neurol India. 2005;53(2):246-247. doi:10.4103\/0028-3886.16433"},{"issue":"5","key":"bib8","series-title":"J Neurol Neurosurg Psychiatry","first-page":"679","article-title":"Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case","volume":"69","author":"Strauss","year":"2000","unstructured":"Strauss CNaraghi RBischoff BHuk WJRomst\u00f6ck J.Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case. J Neurol Neurosurg Psychiatry. 2000;69(5):679-682. doi:10.1136\/jnnp.69.5.679"}],"container-title":["Journal of Neurosurgery: Case Lessons"],"original-title":[],"link":[{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-case-lessons\/11\/21\/article-CASE2634.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-case-lessons\/11\/21\/article-CASE2634.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-case-lessons\/11\/21\/article-CASE2634.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T00:39:47Z","timestamp":1779842387000},"score":1,"resource":{"primary":{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-case-lessons\/11\/21\/article-CASE2634.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,25]]},"references-count":16,"journal-issue":{"issue":"21"},"URL":"https:\/\/doi.org\/10.3171\/case2634","relation":{},"ISSN":["2694-1902"],"issn-type":[{"value":"2694-1902","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,25]]}}}