PMC6335722_01
Highly inferior migrated disc combined with spinal canal and lateral recess stenosis. (a) Preoperative sagittal and axial T2-weight MRI showing ruptured right side inferior migrated disc material combined with central canal and lateral recess stenosis at L4-5. Red arrow: inferior migrated disc; red circle: stenotic region in spinal canal and lateral recess. (b) Postoperative axial and sagittal T2-weight MRI and CT showing the removed inferior migrated disc materials and decompression of lateral recess at L4-5. Red arrow: decompressed area by removal of inferior migrated disc materials; red circle: decompressed area from preoperative stenosis; blue dotted line: resected plane of superior articular process. (c) Part of inferior migrated disc materials was seen by retraction of flexible probe. Dotted blue line: resected ventral plane of superior articular process by reamers; asterisk: tip of inferior migrated disc materials. (d) Further decompression of lateral recess was performed by drilling. (e) Intraoperative C-Arm image showing the location of drill tip during lateral recess decompression. (f) Totally decompressed traversing root was seen at the end stage of operation blue dotted line: dorsal margin of the traversing root.
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fig1
Magnetic resonance (MR) images demonstrated disc extrusion and downmigrated disc herniation combined with spinal canal and lateral recess stenosis at L4-5 level (Figure 1(a)). The blue stained inferior migrated ruptured disc was seen beyond the partially resected superior articular process (SAP) (Figure 1(e)). The ligament flavum was also removed, reaching the spinal canal by an endoscopic punch (Figures 1(c) and 1(d)). This resulted in the whole traversing root being exposed (Figure 1(f)). Postoperative MR and CT images (Figure 1(b)) showed complete removal of the ruptured disc fragment and decompressed lateral recess area.
PMC6335722_02
Single level multi-focal, paracentral, and far-lateral lumbar disc herniations. (a) Preoperative sagittal and axial T2-weight MRI showing multifocal, paracentral, and far-lateral lumbar disc herniations at L3-4. Red arrows: paracentral and extraforaminal disc herniation. (b) Postoperative axial and sagittal T2-weight MRI showing the removed paracentral and far-lateral lumbar disc herniations at L3-4. Red arrows: decompressed area by removal of paracentral and extraforaminal disc herniation. (c) Paracentrally herniated disc materials were removed and decompressed traversing root was seen. PLL: posterior longitudinal ligament. (d) Change of working cannula angle showing the foraminal area. Asterisk: tip of remnant extraforaminal disc; dotted blue line: disc level.
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fig2
MR images revealed intracanal and extraforaminal multifocal soft disc herniation at the L3-4 level (Figure 2(a)). After removal of the herniated disc in the paracentral area (Figure 2(c)), working cannula was slightly withdrawn and reapproached with a stiff angle in order to confirm compressed exiting root. Another stained ruptured disc fragment was found at the axilla area of exiting root by a gentle circular twisting motion of working cannula (Figure 2(d)). MR images showed successful simultaneous removal of paracentral and extraforaminal double disc herniations (Figure 2(b)).
PMC6335722_03
Bilateral disc herniations on L5-S1. (a) Preoperative sagittal and axial T2-weight MRI showing thecal sac compression due to L5-S1 bilateral disc herniations. Red arrows: bilateral disc herniations compressing thecal sac. (b) Postoperative axial and sagittal T2-weight MRI showing decompressed thecal sac and bilateral S1 root by removal of bilateral disc herniation at L5-S1. (c) Ruptured disc material seen at ipsilateral axilla area of S1. PLL: posterior longitudinal ligament. (d) Tip of contralateral ruptured disc was exposed by retraction of thecal sac. Asterisk: tip of the ruptured disc from contralateral epidural space.
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fig3
MR images showed L5-S1 bilateral herniated disc (Figure 3(a)). S1 root, epidural dissection by various endoscopic instruments, a working channel was inserted into the axillary area of S1 root. Sequestrated disk materials located on the ipsilateral side were found and removed with forceps (Figure 3(c)). Another protruded disc was identified under thecal sac on the contralateral side (Figure 3(d)). Postoperative MR images revealed that preoperative herniated discs were successfully removed bilaterally (Figure 3(b)).
PMC6335722_04
Extraforaminal disc herniation combined with central canal stenosis. (a) Preoperative sagittal and axial T2-weight MRI showing foraminal disc herniation combined with central canal stenosis. Red arrows: extraforaminal disc; red circle: stenotic region in spinal canal. (b) Postoperative axial and sagittal T2-weight MRI showing decompressed thecal sac and contralateral L4 root after removal of extraforaminal disc herniation at L4-5. Red arrows: decompressed area by removal of extraforaminal disc; red circle: enlarged spinal canal from preoperative stenosis. (c) Contralateral extraforaminal disc seen under the contralateral exiting root. Asterisk: ruptured extraforaminal disc; green dotted line: inferior margin of contralateral exiting root; blue dotted line: contralateral margin of thecal sac. (d) Intraoperative C-Arm image showing the location of forceps grasping protruded contralateral extraforaminal disc materials. (e) Decompressed both contralateral exiting and traversing root. Asterisk: removed site of extraforaminal disc. Blue dotted line: contralateral exiting and traversing root.
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fig4
MR images of the lumbar spine revealed extraforaminal disc combined with central canal stenosis on L4-5 (Figure 4(a)). Gentle retraction of the contralateral thecal sac from the lateral to medial direction revealed a protruded contralateral side extraforaminal disc which was removed by endoscopic forceps (Figures 4(c) and 4(d)). Finally, successfully decompressed contralateral exiting and traversing nerve root was confirmed (Figure 4(e)). Postoperative MR images showed complete removal of ruptured extraforaminal disc fragments and decompressed spinal canal (Figure 4(b)).