Extracapsular dissection in peripheral nerve schwannoma surgery using bright light and fluorescein sodium visualization: case series
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Schwannomas are the most frequent peripheral nerve sheath tumors and are treated by surgical resection when symptomatic. Tumor removal is performed by intraneural dissection and enucleation. In order to safely remove the tumor from the nerve, the use of sodium fluorescein has recently been proposed to distinguish the tumor from the adjacent normal nerve fibers, before incision of the tumor pseudocapsule and during intraneural tumor dissection.
We report a consecutive case series of 5 peripheral nerve schwannomas operated in 4 patients, in which we evaluate the usefulness of sodium fluorescein compared to usual visual landmarks, at each step of the surgical procedure.
After exposition of the schwannoma, sodium fluorescein helped with the localization of intracapsular en passant nerve fascicles in only one case. Hence, the definition of a safe entry zone for capsular incision relied mainly on nerve monitoring and direct visualization of en passant nerve fascicles under microscope. During intraneural dissection, there was a sharp contrast between the fluorescent tumor and the non-fluorescent adjacent pseudocapsule in most cases but the colorimetric variation between tumor and normal tissue induced by fluorescence did not outperform the natural contrast between the yellow true capsule and the gray-red layers of the pseudocapsule.
Based on these results, we consider that the limited additional value of sodium fluorescein in primary peripheral nerve schwannoma surgery does not warrant its use in daily clinical practice. Additional studies are needed to assess its usefulness during the surgery of recurrences and tumors which are intertwined with several fascicles of origin such as neurofibromas.
KeywordsPeripheral nerve sheath tumors Schwannoma Sodium fluorescein NF2
We would like to thank Mr. Pinto at Zeiss France for the 2-month trial of the YELLOW 560 filter.
Compliance with ethical standards
Conflict of interest
All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed in this manuscript.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the Pitié-Salpêtrière research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
All four patients have consented to the submission of the case reports to the journal.
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