Richard Ozuna

A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermittent claudication : Two-year follow-up results

Study Design. A randomized, controlled, prospective multicenter trial comparing the outcomes of neurogenic intermittent claudication (NIC) patients treated with the interspinous process decompression system (X STOP) with patients treated nonoperatively. Objective. To determine the safety and efficacy of the X STOP interspinous implant. Summary of Background Data. Patients suffering from NIC secondary to lumbar spinal stenosis have been limited to a choice between nonoperative therapies and decompressive surgical procedures, with or without fusion. The X STOP was developed to provide an alternative therapeutic treatment. Methods. 191 patients were treated, 100 in the X STOP group and 91 in the control group. The primary outcomes measure was the Zurich Claudication Questionnaire, a patient-completed, validated instrument for NIC. Results. At every follow-up visit, X STOP patients had significantly better outcomes in each domain of the Zurich Claudication Questionnaire. At 2 years, the X STOP patients improved by 45.4% over the mean baseline Symptom Severity score compared with 7.4% in the control group; the mean improvement in the Physical Function domain was 44.3% in the X STOP group and −0.4% in the control group. In the X STOP group, 73.1% patients were satisfied with their treatment compared with 35.9% of control patients. Conclusions. The X STOP provides a conservative yet effective treatment for patients suffering from lumbar spinal stenosis. In the continuum of treatment options, the X STOP offers an attractive alternative to both conservative care and decompressive surgery.

Regional variations in certain cellular characteristics in human lumbar intervertebral discs, including the presence of α-smooth muscle actin

An evaluation of the regional variation of certain cellular features in the human intervertebral disc (IVD) could lead to a better understanding of site‐specific properties relative to degradation, response to injury, and healing processes. The objective of this study was to determine how cell density, cell morphology, cell grouping, and expression of a specific actin isoform varied with location and degeneration in the human disc. A total of 41 human L4‐L5 and L5‐S1 discs removed postmortem from 21 individuals were analyzed. The discs were graded for degeneration based on the Thompson scale and processed for evaluation. Microtomed sections from paraffin‐embedded specimens were stained with hematoxylin and eosin or a monoclonal antibody to α‐smooth muscle actin (α‐SMA), an actin isoform often associated with contraction. A significant regional dependence was found for most of the measured parameters. A fourfold increase in cell density was found in proceeding from the nucleus pulposus (NP) to the outer annulus (OA) of the IVD. Approximately 30% of the cells in the NP were present in groups. Virtually all of the cells in the NP and 40% of those in the OA were round. Moreover, notable percentages (12–15%) of the cells in the NP and inner annulus (IA) contained α‐SMA. Only pair density was found to be correlated with Thompson grade, with more degenerated specimens having higher values. A greater effect was also observed on the percentage of cells in groups. These findings provide the basis for future work to investigate the importance of cells in groups, the role of α‐SMA in the disc, and the changes in these cellular characteristics in pathological disc conditions.

Alpha-smooth muscle actin in pathological human disc nucleus pulposus cells in vivo and in vitro.

That a contractile actin isoform has been found in cells of other cartilage tissues in healing and disease states prompted this investigation of the presence of α‐smooth muscle actin (α‐SMA) in pathological human intervertebral disc tissue. The presence of this isoform has been reported in human intervertebral disc specimens obtained at autopsy from subjects for whom there were no reported symptoms. An objective of this study was to evaluate the cell density and percentage of α‐SMA–containing cells in pathological nucleus pulposus tissue obtained from lumbar disc surgery from 17 patients. Additionally, explants of nucleus pulposus material were cultured to determine how α‐SMA expression changed with time in vitro. Seventy‐six 5‐mm diameter explants (approximately 2 mm thick) pooled from six lumbar surgeries were cultured for 1, 2, 4, or 6 weeks. Microtomed sections of paraffin‐embedded specimens were stained with hematoxylin and eosin or a monoclonal antibody to α‐SMA. Histologically, cells were categorized as to α‐SMA phenotype (positive or negative), and the areal cell density was determined. The evaluation of the cultured nucleus pulposus explants also included documentation of the percentage of cells that were round or elongated and the percentage of the cells that were part of a group (group: ≥ 2 cells). Every nucleus pulposus section exhibited the presence of α‐SMA–containing cells, which accounted for approximately 24 percent of the cells in vivo. In vivo, the cell density was significantly higher in older individuals (p = 0.02). The average time for cell outgrowth from the explants was 8.6 days. Approximately 10–15 percent of the cells in the explants stained positive for α‐SMA. The time in culture had no significant effect on any of the outcome measures except the percentage of α‐SMA–containing cells that were round (p = 0.008), with values decreasing through 4 weeks and then slightly rising at 6 weeks. The role of α‐SMA in intervertebral disc pathology warrants further investigation.

9:26 Treatment of lumbar spinal stenosis with an interspinous spacer

Abstract Purpose of study: A newly developed spinal implant for the treatment of symptomatic lumbar spinal stenosis is being evaluated in a prospective randomized multicenter study. The implant is placed between the spinous processes of the affected level(s), and the intent is to position the stenotic segment in slight flexion, and by preventing extension, the symptoms of lumbar spinal stenosis will be relieved. The primary objective of this study is to evaluate the safety and efficacy of the implant in a clinical trial setting. Methods used: The surgical implantation of the implant is performed under local anesthesia and routinely requires 30 minutes to 1 hour of surgical time. There is negligible blood loss. The patients typically return home 3 hours after surgery. Two hundred nine patients with neurogenic claudication at the L3–L4 and/or L4–L5 levels have been enrolled in the randomized prospective study. One hundred fifteen of these patients have received the implant (X-Stop; St. Francis Medical Technologies, Concord, CA), and 94 have been treated conservatively including epidural injections. Before surgery, all patients completed an initial Zurich Claudication Questionnaire (ZCQ). The ZCQ is a self-administered survey developed to be a spinal stenosis specific outcome measure consisting of symptom severity, physical function and satisfaction scales [1] . A patient must improve in each of the three categories to be considered a success. In the current study, the ZCQ scores were available for comparison between the implant and conservative groups at 6-week, 6-month and 1-year time points. The two groups were compared statistically using Fishers exact test (p of findings: To date, 209 patients have completed the 6-week ZCQ (115 implant and 94 conservative), 176 have completed the 6-month ZCQ (91 implant and 85 conservative) and 100 have completed the 1-year questionnaire (46 implant and 54 conservative). The overall success rates for the implant group are significantly greater than those of the conservative group at each time point (Table 1) Table 1 . Success rates of the implant and conservative groups Implant success Conservative success p Value 6 weeks 66/115 (57%) 9/94 (10%) 6 months 50/91 (55%) 5/85 (6%) 1 year 32/46 (70%) 1/54 (2%) . Moreover, at 1 year the success rates for the symptom severity, physical function and satisfaction categories were 86%, 83% and 88%, respectively, for the implant group, and 11%, 11% and 28% for the conservative group. Relationship between findings and existing knowledge: The results of this study demonstrate that the implant may be effective in treating pain in patients with lumbar spinal stenosis. This series of patients demonstrates the relative safety and efficacy of a newly developed spinal implant for the treatment of symptomatic lumbar spinal stenosis. In many ways this short-term preliminary follow-up compares favorably to traditional surgical treatment as well as nonsurgical treatment in selected cases. The surgical procedure is minimally invasive, inexpensive and safe. There were no intraoperative complications. Finally, the measurement instrument has been demonstrated to be responsive and sensitive enough to measure clinically significant improvements in mild to severe cases. Overall significance of findings: These findings indicate that the implant may be an effective means of treating painful and debilitating symptoms of lumbar spinal stenosis. Disclosures: Device or drug: X-Stop, Investigational Device Exemption (IDE). Status: investigational. Conflict of interest: Scott Yerby, stockholder; James Zucherman, stockholder; Ken Hsu, stockholder.