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. 2021 Jul 27;12:373. doi: 10.25259/SNI_340_2021

Figure 1:

Figure 1:

(Patient 1) (a) Photograph showing a subcutaneous lipoma at the lumbosacral region. Sagittal views of a three-dimensional heavily T2-weighted image (3D-hT2WI, slice thickness of 1.25 mm) (b) and a 3D variable flip angle T1-weighted image (3D-T1WI, slice thickness of 1.25 mm) (c) depict a low-lying conus medullaris at the vertebral level of L5 that is tethered by dorsal lipoma, and cord-like structure (C-LS) extends from the conus and terminates at the dural cul-de-sac at S4-5 level without much tapering. Schematic drawings (d) and microscopic view of the operative findings (e), and intraoperative neurophysiological monitoring (f). (d-1) A linear skin incision on the subcutaneous lipoma and a subsequent incision on the rostral side are made. (d-2) Passage of the lipoma through the dura mater is noted at L4 level, and the dura incision is made on the rostral site to the lipoma passage. (d-3) With the dura opened, the intradural component of lipoma is exposed. (d-4) Lumbar cord is untethered from the lipoma. The dura incision is made on the caudal site to the lipoma passage and extended to the dural cul-de-sac. (d-5, e) With the dura opened, C-LS is continuous from the conus to the dural cul-de-sac. The exact border between the C-LS and the true conus is determined by tracing the evoked compound muscle action potentials of the external anal sphincter muscle (f) with direct stimulation starting from the functional portion of the conus (1-4) and continuing to the nonfunctional portion of the C-LS (5 and 6), and indicated by the yellow line in (e). C-LS is severed immediately caudal to the exact border (indicated with red line in (e)). (d-6) Caudal end of the C-LS is also severed, and the C-LS is resected as column. Finally, the lipoma is debulked, and the pial surface is reconstructed with sutures. (e-g) Photomicrograph of longitudinal sections of the C-LS stained with hematoxylin and eosin (H and E) (e) and immunostained for glial fibrillary acidic protein (GFAP) (f and g). A higher magnification view of the area indicated by the dotted square in (f) is shown in (g). In the marginal part of the fibrocollagenous tissue of the C-LS, a central canal-like, ependyma (Epen)-lined canal with surrounding GFAP-immunopositive neuroglial tissues is noted (indicated with red arrows in (e) and (f)). No adipose tissue is noted.