Figure 1.  Left: Photograph showing two identically sized cylindrical interbody fusion spacers, both 10 mm tall and 13 mm in diameter, with 2-mm-thick walls (both manufactured by Medtronic Sofamor Danek, Inc., Memphis, TN). The device on the left side of the panel is the HYDROSORB spacer, which is manufactured from a bioabsorbable polymer. The device on the right side is a titanium mesh cage (Pyramesh). Right: Photograph showing a HYDROSORB bioabsorbable spacer mounted on an angled inserter that is designed to allow insertion of the device into the prepared disc space (contralateral to the side of the anular window) during the TLIF procedure. Photographs are reprinted with permission from Slack, Inc.

Figure 2.  Left: Photograph showing the distractor. This device is designed to distract the heads of the multiaxial pedicle screws while maintaining wide access to the foramen. Right: Intraoperative photograph showing the distractor in situ. Note how the intervertebral disc can be easily approached between the heads of the multiaxial screws. Photographs are reprinted with permission from Slack, Inc.

Figure 3. Photograph showing a left-facing angled and serrated curette that facilitates preparation of the vertebral end-plate during the TLIF procedure. Not shown are similar straight and right-facing serrated curettes. Photograph is reprinted with permission from Slack, Inc.

Figure 4.  Left: Photograph showing two HYDROSORB spacers loaded on straight and angled inserters and packed with autologous bone graft in preparation for insertion into the prepared intervertebral disc space. Right: These straight and angled impactors are used to adjust the implant position after insertion. To avoid cracking the HYDROSORB implants, it is important to avoid excessive force when using these impactors. Photographs are reprinted with permission from Slack, Inc.

Figure 5. Intraoperative photograph showing a HYDROSORB bioabsorbable spacer visualized through the anular window after insertion. The top of the photograph is oriented medial, left is oriented caudally. Photograph is reprinted with permission from Slack, Inc.

Figure 6. This 41-year-old man with isthmic Grade I spondylolisthesis had undergone an anterior decompression, titanium mesh cage implantation, fusion, and instrumentation for an L-3 burst fracture with neurological deficit (which resolved postoperatively) 6 years before a lifting injury that rendered his spondylolisthesis symptomatic. Upper Left: Lateral radiograph demonstrating the anterior implants spanning L2–3. Upper Center: A detailed lateral radiograph of the lumbosacral junction indicating the loss of intervertebral disc height in addition to the spondylolisthesis. Upper Right: Lateral radiograph obtained 2 weeks postoperatively demonstrating the restoration of the L5–S1 intervertebral disc height and partial reduction of the spondylolisthesis as well as the posterior transpedicular implants spanning L2–S2. Note that the lordosis between L-3 and S-1 is preserved. Preoperative discography had indicated that the L4–5 disc was too degenerated and symptomatic not to be included in the fusion. Lower Left: Postoperative anterior–posterior radiograph obtained at 2 weeks. Lower Right: Lateral radiograph obtained 1 year postoperatively indicating solid interbody fusion at L4–5 and L5–S1 with preservation of disc height and lumbar lordosis.

Figure 7. This 39-year-old man underwent a single-level TLIF for degenerative disc disease and a central disc herniation. Upper Left: Preoperative lateral radiograph. Upper Right: Lateral radiograph obtained 2 weeks postoperatively. Lower Left: Lateral radiograph obtained 6 months postoperatively. Note that the disc space height is well preserved with only minimal loss of lordotic angulation of the intervertebral endplates. Note also that the bone density throughout the entire disc space is well preserved, indicating probable progression toward solid arthrodesis. Lower Right: A solid trabeculated interbody fusion in the posterior two thirds of intervertebral disc space is demonstrated in a lateral radiograph obtained 12 months postoperatively. Note the absence of kyphosis and subsidence compared with the 6-month film.

Figure 8. Bar graph showing SF-36 data in 19 of 31 patients in whom 12-month postoperative mean scores are compared with preoperative mean scores. Note that there were statistically significant improvements in the mean pain and physical function scores.