PMC4732253_01
(a) Preoperative lumbar radiograph demonstrating retropulsion of interbody cage at L5-S1. (b) Sagittal T2-weighted lumbar magnetic resonance imaging (MRI) notable for herniated lumbar interbody with the compromise of the central canal. (c) Axial T2-weighted lumbar MRI is notable for centrally herniated interbody with nerve rootlet compression. Intraoperative images demonstrate (d) the dorsal thecal sac, which is opened sharply using a number 11 blade. (e) The nerve rootlets are gently retracted to either side using a Penfield number 6. (f) The ventral dura is opened sharply, (g) exposing the herniated interbody.(h) A threaded cage inserter is placed into the interbody and (i) gentle rocking motion allows retrieval of the interbody from the disk space, through the ventral dural opening and out of the dorsal dural opening, all while nerve rootlets are visualized and protected. (j) Noncompressed Gelfoam (Pfizer, New York, NY) is placed in the vertebral interspace, and the ventral and dorsal dura are closed in watertight fashion using 6-0 Prolene (Ethicon Endo-Surgery, Inc., Blue Ash, OH) sutures. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.
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F1
Radiological workup with radiographs and magnetic resonance imaging of the lumbar spine were notable for retropulsion of the L5-S1 interbody cage into the spinal canal, otherwise excellent positioning of the L4-5 interbody, and pedicle screws with posterolateral bridging bone [Figure 1a and b]. Considering the prolonged interval between the index surgery and the time of presentation to our clinic and the exact central position of the retropulsed interbody [Figure 1c], we were concerned that significant scar tissue and osteophytic ridge formation would hinder visualization of the graft and place the surrounding neural tissue at risk due to the retraction that would be necessary if the interbody were accessed via the original surgical corridor. The thecal sac was opened with a number 11 blade in a linear fashion [Figure 1d], and after the egress of CSF, the dura was tacked to the muscle margins. With the retraction of intradural sacral roots [Figure 1e], the herniated interbody was easily visible and palpable through the ventral dura; it was compressing the left-sided exiting sacral rootlets. A Penfield number 2 was used to gently retract the nerve rootlets to either side, and a number 11 blade was once again used to open the ventral dura in a linear fashion directly over the herniated interbody [Figure 1f and 1g]. Once open, the ventral dura was retracted to either side of the herniated interbody, and a graft inserter was threaded into the interbody [Figure 1h]. Using repetitive rocking motions medially/laterally to disrupt any bridging osteophytes attached to the interbody, wecarefully shimmied the cage out through the ventral dura, traversing the thecal sac, and finally out through the opening in the dorsal dura [Figure 1i]. The dura was closed in sequential fashion, ventrally then dorsally, using 5-0 Prolene sutures (Ethicon Endo-Surgery, Inc., Blue Ash, OH) and buttressed with DuraSeal (Covidien, Mansfield, MA) sealant [Figure 1j].
Postoperative lumbar radiograph notable for extension of fusion from L3 to S1 and successful retrieval of interbody cage. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.
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F2
Segmental fixation was completed with titanium rods locked in place from L3 to S1, along with autograft/allograft bone placed posterolaterally [Figure 2].