OBJECTIVE By modifying existing microendoscopic discectomy techniques, we previously developed a novel surgical treatment of lumbar stenosis and validated its ability to achieve a thorough decompression in a cadaveric study. We now describe our clinical experience with this new, minimally invasive microendoscopic decompressive laminotomy (MEDL) technique. METHODS A MEDL was performed in 25 patients with classic features of lumbar stenosis. By use of a fluoroscopically guided percutaneous technique, the working portal was docked on the lamina with minimal soft-tissue injury. With the angle of the endoscope combined with an oblique entry, a bilateral bony and ligamentous decompression was achieved under the midline, thereby preserving the supraspinous–interspinous ligaments and contralateral musculature. A second group of 25 patients treated with open decompression was used for comparison. RESULTS Effective circumferential decompression was achieved in the majority of patients. The results for the MEDL group were as follows: operative time, 109 minutes per single level; blood loss, 68 ml; and postoperative stay, 42 hours. The results for the open-surgery group were as follows: operative time, 88 minutes; blood loss, 193 ml; and postoperative stay, 94 hours. The MEDL group needed significantly less narcotic medication after surgery. Overall, 16% of the MEDL patients reported resolution of their back pain, 68% improved symptomatically, and 16% remained unchanged. The outcome of the open group was very similar. CONCLUSION Compared with an equivalent open technique, MEDL appears to offer a similar short-term clinical outcome with a significant reduction in operative blood loss, postoperative stay, and use of narcotics. This lower surgical stress, decreased tissue trauma, and quicker recovery are particularly important in this elderly population of patients.

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OBJECTIVE The wide exposure required for a standard posterior lumbar interbody fusion (PLIF) can cause unnecessary trauma to the lumbar musculoligamentous complex. By combining existing microendoscopic, percutaneous instrumentation and interbody technologies, a novel, minimally invasive, percutaneous PLIF technique was developed to minimize such iatrogenic tissue injury (MIP-PLIF). METHODS The MIP-PLIF technique was validated in three cadaveric torsos with six motion segments decompressed and fused. Preoperative variables measured from imaging included interpedicular distance, pedicular height and width, interspinous distance, lordosis, intervertebral height, Cobb angle, and foraminal height and volume. Using the METRx and MD spinal access systems (Medtronic Sofamor Danek, Memphis, TN), bilateral laminotomies were performed using a hybrid of microsurgical and microendoscopic techniques. The intervertebral disc spaces were then distracted and prepared with the Tangent (Medtronic Sofamor Danek) interbody instruments. Either a 10 or 12 by 22 mm interbody graft was then placed. Using the Sextant (Medtronic Sofamor Danek) system, percutaneous pedicle screw-rod fixation of the motion segment was completed. We then applied MIP-PLIF in three patients. RESULTS For segments with preoperative intervertebral/foraminal height loss, MIP-PLIF was effective in restoring both heights in all cases. The amount of improvement (9.7 to 38% disc height increase; 7.7 to 29.9% foraminal height increase) varied directly with the size of the graft used and the original degree of disc and foraminal height loss. Segmental lordosis improved by 29% on average. Graft and screw placement was accurate in the cadavers, except for a single Grade 1 screw violation of one pedicle. The average operative time was 3.5 hours per level. In our three clinical cases, the MIP-PLIF procedure required a mean of 5.4 hours, estimated blood loss was 185 ml, and inpatient stay was 2.8 days, with no intravenous narcotic use after 2 days in any of the patients. All screw and graft placements were confirmed. CONCLUSION A complete PLIF procedure can be safely and effectively performed using minimally invasive techniques, thereby potentially reducing the pain and morbidity associated with standard open surgery. Prospective, randomized outcome studies will be required to validate the efficacy of this exciting new surgical technique.