DESCRIPTION OF PROCEDURE
Having appropriately positioned her, we then prepped and draped her back in the appropriate fashion. We marked off levels of her spine with spine needles for marking over the top of the pedicle facet complexes, and localized her incision using C-arm guidance. The skin was marked with a midline incision. The skin was infiltrated with 1% lidocaine-epinephrine. The skin was then opened with monopolar cautery and strict attention to hemostasis was paid using bipolar and monopolar cautery. We divided the underlying subcutaneous tissues with monopolar cautery and advanced self-retaining retractors within the wound. We took down the paraspinous musculature insertions off the spinous process and lamina of T6-T11 and extended the muscle resection laterally over the bodies of T7, T8, T9 and T10 going out over the costal margins bilaterally. Having obtained our exposure, we then placed our self-retaining Gelpi retractors within the wound. We verified the location of the T8-T9 interspace using C-arm guidance, and this was marked indelibly. We then took down the spinous processes using a Leksell rongeur and saved this bone for later autograft. We thinned down the lamina using the Leksell rongeur, and then were able to develop a plane at the lower margin of T9, detaching the ligamentum flavum and then resecting the lamina of T8 and T9. With doing so, we did expose the central thecal sac. We did have intermittent loss of the motor evoked potential in the right lower extremity. Arrest was given to the case and anesthesia was lightened. This did improve somewhat with the exception of the quadriceps. We maintained this new baseline throughout the case with a severely decreased quadriceps motor evoked potential. Having completed our midline exposure, we then removed the T8-T9 facet complex bilaterally, as well as the rib head of T8. This provided us excellent exposure of the lateral margins of the vertebral body, exposing the T8-T9 disc space. We used the Midas Rex with an AM-8 bit to drill down the T9 pedicle, likewise improving and extending our exposure. Having completed our exposure, we then, using loupe magnification with headlight augmentation, incised the T8-T9 disc space sharply. We used a variety of Epstein down-biting curets to gently detach the dura from the PLL, and delivered the disc material into a trough that had been drilled underneath the thecal sac with a Midas Rex with an AM-8 bit. We were able to successfully do this, particularly on the left-hand side. However, on the right-hand side, the disc was tightly adherent to the dura. We did, using microdissection, attempt to detach the T8-T9 disc, the dura was opened. This proved that the disc herniation itself was intradural. We draped and brought the operating microscope within the field. We packed off the lateral recess regions with Cottonoids containing a dry field. We incised the dura sharply with a #15 blade and extended the durotomy using sharp microdissection. We tacked back the dural edges with a series of 4-0 Nurolon sutures. On the right-hand side, we identified 2 dentate ligaments. The dentate ligaments were incised with spring-type microscissors. There was a vascular loop that did come laterally from the dural surface out onto the dorsal aspect of the spinal cord. We did have to work around this in order to preserve this. Using careful microdissection, we were able to gently roll the right lateral aspect of the cord and expose the underlying calcified herniated disc which was intradural. This was sharply dissected off the dura using a #11 blade and delivered into our cavity created in the T8-T9 disc interspace. We were then able to reach in laterally, grab this with a small pituitary, and incise the last dural piece which was attaching it. There was no evidence of attachment onto the spinal cord itself. We then performed a dural patch by taking a small pledget of dura/paradural placement product, and sliding it between the spinal cord and the dural defect. This was tacked up against the dura using a series of 4-0 Nurolon sutures. We then created a sling of dura/paradural placement product and placed this underneath the thecal sac and sutured this in place as well. This did provide somewhat of a watertight seal. Having completed this, we then closed the dura with a running 5-0 Prolene suture. The suture line was watertight. We then attached the Stealth target to the spinous process of T7. We covered the wound and draped the patient appropriately. We brought the O-arm within the field. We did an O-arm scan of the patient's thoracic spine, and registered it within 3-dimensional space. We then removed the O-arm and brought the C-arm within the field. We verified the accuracy of our Stealth image guidance. Using Stealth image guidance with lateral C-arm fluoroscopy, we cannulated the bodies of T7, T8, T9 and T10, each time probing the pedicle screw path to ensure that there was no breach. We repeated motor evoked potentials with each placement of the
screw. All screws were pretapped. The screws were then placed into the bodies of T7, T8, T9 and T10 bilaterally using the above-listed screws. We repeated our motor evoked potentials. This was unchanged. We distracted the T8-T9 interspace. We then placed a 25 mm x 8 mm Verte-Stack rescent PEEK withinthe discectomy space. We verified its placement using C-arm. There was no change in motor evoked potentials. It was clear that the dura was well decompressed with no pressure from the Verte-Stack graft. We then compressed across the graft at T8-T9 and tightened the set screws. We then irrigated the wound again with copious amounts of normal saline. We sized and placed 2 x 5.5 mm x 10 cm precut rods. We obtained AP and lateral thoracic spine films. The placement of the screws and the rods was excellent. We tightened down all the set screws to their endpoints. We placed two 5.5 mm cross-links. We then decorticated the posterolateral elements. We laid down a small BMP pack along the posterolateral elements and used the patient's autograft mixed with pyogenic demineralized bone matrix laterally. We then approximated the muscle with a series of interrupted 0 Vicryl sutures, followed by closely spaced 0 Vicryl to the fascia, followed by interrupted, inverted 2-0 Vicryl to Scarpa's fascia, followed by nterrupted, inverted 3-0 Vicryl to the subdermal tissues, followed by staples to the skin. At the end of this procedure, all sponge and needle counts were correct. The patient was extubated and transferred to the PACU in stable condition.
