- Email: [email protected]
6:18 171. Artificial disc vs. fusion for the treatment of cervical radiculopathy: a prospective randomized study
88S
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
study retrospectively looks at those patients in the CSSG who underwent occipitocervical fusion and seperates them into non rigid and rigid fixation groups. PATIENT SAMPLE: Group 1 consisted of patients who underwent non rigid fixation and Group 2 consisted of patients who underwent rigid fixation. Group 1 had 26 patients with an average age of 58 and Group 2 consisted of 42 patients with an average age of 60. OUTCOME MEASURES: Complications for both groups were identified and itemized. A statistical analysis (t-test) of the incidence of complication of the two groups was performed to determine significance. METHODS: Preoperative, intra-operative and postoperative courses were investigated for each patient in both groups. Diagnosis, operative techniques, intra-operative and postoperative complications were recorded for each patient. Postoperative follow-up visit notes and relevant radiological films were examined as needed. Each type of data (eg, diagnosis, complications, etc.) was recorded in an Excel spread sheet. Data analysis on the final data was performed. RESULTS: Group 1 had a total of 26 patients with 26 procedures while Group 2 consisted of 42 patients with 42 procedures. Group 1 had 14 complications (53%) while Group 2 had 3 complications (7%) (p⬍.05). CONCLUSIONS: When compared with nonrigid fixation supplemented by external immobilization, rigid occipitocervical fusion significantly decreases complications. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.172
outcomes instruments consistently showed more improvement for the multilevel cases. The mean improvement in the NDI for the single cases was 43.8% (⫾20.9) versus the multilevel cases mean improvement in NDI was 64.8% (⫾33.7). The Mean improvement in the VAS showed the same relationship—single level mean improvement 58.1% (29.3) versus the multilevel cases mean VAS improvement was 65.5% (⫾33.0). The most current Odom’s showed the same relationship. Overall the final outcomes were similar. The reason for the greater improvement in Group M was that in general their baseline disability was greater. There were two major adverse events in each group—two patients in each had prosthesis subluxation requiring return to the OR. CONCLUSIONS: There is clearly a trend of greater instrumentation difficulty and higher pseudarthrosis rates as the length of cervical plates span more vertebral levels. This is not the trend or indicative of this prospective report of cervical arthroplasty where each cervical vertebral level was biomechanically independent of the adjacent levels. With the Porous Coated Motion cervical arthroplasty the incidence of reoperation did not increase proportionately higher as the number of cervical levels requiring instrumentation increased. This study indicates that the current five prospective randomized FDA clinical trials comparing arthroplasty with anterior cervical fusion will underestimate the true benefits of cervical arthroplasty because they are not capturing the data on multiple level application. DISCLOSURES: FDA device/drug: Porous Coated Motion. Status: Investigational/not approved. CONFLICT OF INTEREST: Author (PM) Consultant: Cervitech, DePuy Spine; Author (PM) Stockholder: Cervitech, DePuy Spine; Author (PM) Grant Research Support: Cervitech, DePuy Spine. doi: 10.1016/j.spinee.2005.05.173
6:12 170. Comparison of multiple level vs. single level cervical disc replacement: 178 consecutive prostheses Paul McAfee, MD1, Luiz Pimenta2, Andrew Cappuccino, MD3, Alan Crockard 4, Bryan Cunningham, MSc5; 1Spine and Scoliosis Center, Towson, MD, USA; 2Sao Paulo, Brazil, Brazil; 3Lockport, NY, USA; 4National Hospital for Neurology and Neurosurgery, London, United Kingdom; 5Union Memorial Hospital, Baltimore, MD, USA BACKGROUND CONTEXT: The prospective FDA randomized clinical trials investigating disc replacement are all based on single level cervical disc disease and randomize against allograft fusion and a single level plate. PURPOSE: This series of 178 prosthetic implantations prospectively compared single level versus multiple level cervical arthroplasty. STUDY DESIGN/SETTING: Prospective Consecutive Non-Randomized Design. PATIENT SAMPLE: 55 patients underwent single level Porous Coated Motion (PCM) cervical arthroplasties. Fifty-four patients underwent 109 multilevel PCM cervical arthroplasties during the same time interval, for the same indications, performed by the same surgeons under the same clinical protocol—double level, 43 cases; three levels, 7 cases, and four levels, 4 cases. OUTCOME MEASURES: NDI, VAS, TGIT, Odoms, and SF-36. METHODS: 16 PCM cases had been performed as complex revision procedures—9 in Group S and 7 in Group M. Sixteen PCM procedures had been performed as complex revision procedures-- 1 previous Bryan Disc, 1 cage-plate, 3 patients had failed lordotic cervical cages, and 17 patients had presented with adjacent segment disease following ACDF (8 with two or more adjacent levels previously immobile—four from Group S and four from Group M). One additional patient in Group M had a fracture-dislocation at C4-5 and a pseudarthrosis at C3-4 and C5-6. The demographics between Group S and Group M were very similar—mean age of patients, gender, severity of neurologic symptoms and distribution of radicular and myeloradicular symptoms. RESULTS: There were no deaths, no infections, and no instances of iatrogenic neurologic progression in either the single level or the multiple level arthroplasty group. The mean EBL, LOS, and surgical duration was greater for multilevel vs. single level cases. The self assessment
6:18 171. Artificial disc vs. fusion for the treatment of cervical radiculopathy: a prospective randomized study Rick Sasso, MD1, John Heller, MD2, Robert Hacker3; 1Indiana Spine Group, Indianapolis, IN, USA; 2Emory University, Atlanta, GA, USA; 3 Eugene, OR, USA BACKGROUND CONTEXT: Artificial cervical disc replacement has recently become an option for treatment of the patient with cervical radiculopathy. Previous studies have retrospectively evaluated the efficacy of this alternative, however, without the scientific rigor of a concurrent control population utilizing conventional surgical techniques. This is the first report of a prospective, randomized study comparing a cervical disc replacement to a standard anterior cervical fusion with results up to 2 years. PURPOSE: The purpose of this study is to examine the initial functional outcome results of this prospective, randomized trial to determine the role of the Bryan artificial cervical disc replacement compared with fusion for patients with a cervical disc herniation or stenosis causing radiculopathy. STUDY DESIGN/SETTING: The data from 3 surgeons involved in the FDA IDE trial of the Bryan cervical disc replacement were evaluated. This is a multicenter prospective, randomized study of patients with cervical radiculopathy or myelopathy due to one level cervical stenosis or disc herniation. The control population is anterior cervical fusion with allograft and a plate. Randomization ratio is 1:1. PATIENT SAMPLE: 115 patients were randomized in a 1:1 ratio to a Bryan artificial disc replacement (56) or an anterior cervical fusion with allograft and a plate (59). There were 30 males and 26 females in the Bryan group and 32 males and 27 females in the fusion group. The average age was 43 years (Bryan) and 46 years (fusion). OUTCOME MEASURES: Neck Disability Index (NDI) Neck pain visual analog pain score (VAS) Arm pain visual analog pain score (VAS) SF-36physical component: (PCS) mental component: (MCS) Range of Motion (ROM) flexion/extension. METHODS: Patients were prospectively evaluated preoperatively as well as at defined intervals postoperatively. RESULTS: The average operative time for the control group was 1.1 hours and the Bryan group 1.7 hours. Average blood loss was 50 cc (control) and
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
89S
66cc (Bryan). Average hospital stay was 0.5 days (control) and 1 day (Bryan). Neck Disability Index score (NDI) preoperatively was 47 (Bryan) and 49 (control). 12 month follow-up data are available for 75 patients (38 Bryan and 37 controls) with NDI 11 (Bryan) and 19 (control). At 2-year follow-up 16 patients are available (8 Bryan and 8 control) NDI for the Bryan group is 7 and control group 26. Arm pain VAS preoperatively was 70 (Bryan) and 71 (control). At 1-year follow-up Bryan arm pain VAS was 14 and control 22. At 2-year follow-up the average arm pain VAS for the Bryan group was 7 and control 45. Neck pain VAS preoperatively was 72 (Bryan) and 73 (control). 1-year follow-up scores were 19 (Bryan) and 28 (control). At 2-years: 10 (Bryan) and 38 (control). SF-36 scores: Physical component- Preoperatively Bryan-34 and control 32. At 24-months: Bryan51 and control-45. Mental component preoperatively: Bryan 46 and control 49. At 24-months: Bryan-55 and control-50. As expected, significantly (p⬍.006 at 3, 6, and 12 months) more motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 6.7 degrees at 12 months. In contrast, the average range of motion in the fusion group was 2.0 degrees at the threemonth follow-up and gradually decreased to 0.6 degrees at 24 months. CONCLUSIONS: The Bryan artificial disc replacement compares very favorable to a conventional anterior cervical fusion for the treatment of patients with cervical radiculopathy. DISCLOSURES: FDA device/drug: Bryan artificial disc. Status: Investigational/not approved. FDA device/drug: allograft bone. Status: Approved for this indication. FDA device/drug: anterior cervical plate. Status: Approved for this indication. CONFLICT OF INTEREST: Author (RS) Consultant: Medtronic.
groups was statistically significantly. Patient satisfaction and SF-36 PCS domain also improved significantly in the IPD group compared with controls. No differences between groups in SF-36 MCS scores and in percent slippage after 2 years were present. Postoperatively, the results were stable over all time periods. Overall clinical success, defined as a minimum 15% improvement in ZCQ and absence of further surgical treatment, was 69% in IPD compared with 9% in controls. This difference was statistically significant.
doi: 10.1016/j.spinee.2005.05.174
F/U⫽follow-up; IPD⫽interspinous process decompression; PCS⫽ Physical Component Summary; ZCQ⫽Zurich Claudication Questionnaire.
Friday, September 30, 2005 6:00–7:00 PM SIPP 2: Novel Technology 6:00 172. Interspinous process decompression (IPD) of patients with neurogenic intermittent claudication secondary to degenerative spondylolisthesis Paul Anderson, MD1, Scott Kitchell, MD2; 1University of WisconsinMadison, Madison, WI, USA; 2NASS, Eugene, OR, USA BACKGROUND CONTEXT: Interspinous process decompression (IPD) theoretically prevents narrowing of the spinal canal and neuroforamina in extension, and thus reduces the symptoms of neurogenic intermittent claudication (NIC). PURPOSE: The purpose of this study was to compare the outcomes of degenerative spondylolisthesis patients treated with the IPD technique to those treated nonoperatively. STUDY DESIGN/SETTING: Randomized controlled trial. PATIENT SAMPLE: 61 patients with neurogenic claudication secondary to degenerative sponylolisthesis at 1 or 2 levels. OUTCOME MEASURES: The validated stenosis-specific Zurich Claudication Questionnaire (ZCQ) range 0–100, SF-36, patient satisfaction, and by lumbar radiographs. Assessments were preoperative, 3, 6, 12, and 24 months. METHODS: An FDA-approved prospective randomized multi-center IDE study with 191 NIC patients included 61 patients with up to Grade I degenerative spondylolisthesis; 39 were treated with IPD (X STOP) and 22 nonoperatively with epidural steroids. The validated, stenosis-specific Zurich Claudication Questionnaire (ZCQ), range 0–100, was administered preoperatively and at 3, 6, 12, and 24 months. Also results were assessed by SF-36, patient satisfaction, and by radiographs. Statistical analysis between groups was by ANOVA. RESULTS: At 2 years, the IPD group improved in ZCQ from 51 to 24 compared with 49 to 50 in the controls (Table 1). The difference between
Table 1 Overall results Control Number of patients ZCQ (0–100) Preop F/U Patient satisfaction Range (0–100) SF-36 PCS Preop F/U Percent slip Number of levels Preop F/U Overall clinical success
IPD
p value
22
39
48.9 (14.7) 50.5 (21.5)
51.2 (12.7) 25.2 (20.2)
⬍0.0001
56.9 (35.40)
21.7 (29.1)
⬍0.0001
29.1 (7.0) 31.6 (8.7)
28.1 (6.4) 40.4 (13.3)
⬍0.0001
27 12.7 (8.9) 11.8 (12.7) 9.1%
53 9.97 (7.5) 11.0 (9.3) 69.2%
⬍0.0001 ⬍0.0001
CONCLUSIONS: The results of the current study demonstrate that interspinous process decompression via the X STOP is more effective in NIC patients with up to Grade I degenerative spondylolisthesis compared with nonoperative treatment. This technique maintainns motion and does not require fusion. Also spondylolisthesis is unchanged after IPD. DISCLOSURES: FDA device/drug: Xstop. Status: Investigational/not approved. CONFLICT OF INTEREST: Author (PA) Consultant: St. Francis Medical Technologies. doi: 10.1016/j.spinee.2005.05.175
6:06 173. Dynamic stabilization of the degenerative lumbar motion segment: the Wallis system Nicholas Boeree, MD; Southampton University Hospital, Hants, United Kingdom BACKGROUND CONTEXT: The Wallis implant was conceived to increase the stiffness of the degenerative segment in order to counterbalance changes related to degenerative disc disease (DDD). The Wallis implant evolved from successful clinical experience in over 300 patients with a first generation implant, supported by detailed biomechanical and finite element studies. PURPOSE: The purpose of the present ongoing study is to demonstrate the safety and effectiveness of this second generation implant against low back pain and functional disability in patients with degenerative disc disease. STUDY DESIGN/SETTING: This study was a prospective, multicenter and open study conducted in 8 centers in 6 countries. PATIENT SAMPLE: 260 consecutive patients (39% female, 61% male) with a mean age of 44 years were treated with Wallis. 37% patients had a principal diagnosis of massive disc herniation, 27% had DDD with Modic type 1 change, 13% had canal stenosis, 9% had recurrence of disc herniation and 5% had L5 sacralization with herniation of the transitional disc.
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
study retrospectively looks at those patients in the CSSG who underwent occipitocervical fusion and seperates them into non rigid and rigid fixation groups. PATIENT SAMPLE: Group 1 consisted of patients who underwent non rigid fixation and Group 2 consisted of patients who underwent rigid fixation. Group 1 had 26 patients with an average age of 58 and Group 2 consisted of 42 patients with an average age of 60. OUTCOME MEASURES: Complications for both groups were identified and itemized. A statistical analysis (t-test) of the incidence of complication of the two groups was performed to determine significance. METHODS: Preoperative, intra-operative and postoperative courses were investigated for each patient in both groups. Diagnosis, operative techniques, intra-operative and postoperative complications were recorded for each patient. Postoperative follow-up visit notes and relevant radiological films were examined as needed. Each type of data (eg, diagnosis, complications, etc.) was recorded in an Excel spread sheet. Data analysis on the final data was performed. RESULTS: Group 1 had a total of 26 patients with 26 procedures while Group 2 consisted of 42 patients with 42 procedures. Group 1 had 14 complications (53%) while Group 2 had 3 complications (7%) (p⬍.05). CONCLUSIONS: When compared with nonrigid fixation supplemented by external immobilization, rigid occipitocervical fusion significantly decreases complications. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.172
outcomes instruments consistently showed more improvement for the multilevel cases. The mean improvement in the NDI for the single cases was 43.8% (⫾20.9) versus the multilevel cases mean improvement in NDI was 64.8% (⫾33.7). The Mean improvement in the VAS showed the same relationship—single level mean improvement 58.1% (29.3) versus the multilevel cases mean VAS improvement was 65.5% (⫾33.0). The most current Odom’s showed the same relationship. Overall the final outcomes were similar. The reason for the greater improvement in Group M was that in general their baseline disability was greater. There were two major adverse events in each group—two patients in each had prosthesis subluxation requiring return to the OR. CONCLUSIONS: There is clearly a trend of greater instrumentation difficulty and higher pseudarthrosis rates as the length of cervical plates span more vertebral levels. This is not the trend or indicative of this prospective report of cervical arthroplasty where each cervical vertebral level was biomechanically independent of the adjacent levels. With the Porous Coated Motion cervical arthroplasty the incidence of reoperation did not increase proportionately higher as the number of cervical levels requiring instrumentation increased. This study indicates that the current five prospective randomized FDA clinical trials comparing arthroplasty with anterior cervical fusion will underestimate the true benefits of cervical arthroplasty because they are not capturing the data on multiple level application. DISCLOSURES: FDA device/drug: Porous Coated Motion. Status: Investigational/not approved. CONFLICT OF INTEREST: Author (PM) Consultant: Cervitech, DePuy Spine; Author (PM) Stockholder: Cervitech, DePuy Spine; Author (PM) Grant Research Support: Cervitech, DePuy Spine. doi: 10.1016/j.spinee.2005.05.173
6:12 170. Comparison of multiple level vs. single level cervical disc replacement: 178 consecutive prostheses Paul McAfee, MD1, Luiz Pimenta2, Andrew Cappuccino, MD3, Alan Crockard 4, Bryan Cunningham, MSc5; 1Spine and Scoliosis Center, Towson, MD, USA; 2Sao Paulo, Brazil, Brazil; 3Lockport, NY, USA; 4National Hospital for Neurology and Neurosurgery, London, United Kingdom; 5Union Memorial Hospital, Baltimore, MD, USA BACKGROUND CONTEXT: The prospective FDA randomized clinical trials investigating disc replacement are all based on single level cervical disc disease and randomize against allograft fusion and a single level plate. PURPOSE: This series of 178 prosthetic implantations prospectively compared single level versus multiple level cervical arthroplasty. STUDY DESIGN/SETTING: Prospective Consecutive Non-Randomized Design. PATIENT SAMPLE: 55 patients underwent single level Porous Coated Motion (PCM) cervical arthroplasties. Fifty-four patients underwent 109 multilevel PCM cervical arthroplasties during the same time interval, for the same indications, performed by the same surgeons under the same clinical protocol—double level, 43 cases; three levels, 7 cases, and four levels, 4 cases. OUTCOME MEASURES: NDI, VAS, TGIT, Odoms, and SF-36. METHODS: 16 PCM cases had been performed as complex revision procedures—9 in Group S and 7 in Group M. Sixteen PCM procedures had been performed as complex revision procedures-- 1 previous Bryan Disc, 1 cage-plate, 3 patients had failed lordotic cervical cages, and 17 patients had presented with adjacent segment disease following ACDF (8 with two or more adjacent levels previously immobile—four from Group S and four from Group M). One additional patient in Group M had a fracture-dislocation at C4-5 and a pseudarthrosis at C3-4 and C5-6. The demographics between Group S and Group M were very similar—mean age of patients, gender, severity of neurologic symptoms and distribution of radicular and myeloradicular symptoms. RESULTS: There were no deaths, no infections, and no instances of iatrogenic neurologic progression in either the single level or the multiple level arthroplasty group. The mean EBL, LOS, and surgical duration was greater for multilevel vs. single level cases. The self assessment
6:18 171. Artificial disc vs. fusion for the treatment of cervical radiculopathy: a prospective randomized study Rick Sasso, MD1, John Heller, MD2, Robert Hacker3; 1Indiana Spine Group, Indianapolis, IN, USA; 2Emory University, Atlanta, GA, USA; 3 Eugene, OR, USA BACKGROUND CONTEXT: Artificial cervical disc replacement has recently become an option for treatment of the patient with cervical radiculopathy. Previous studies have retrospectively evaluated the efficacy of this alternative, however, without the scientific rigor of a concurrent control population utilizing conventional surgical techniques. This is the first report of a prospective, randomized study comparing a cervical disc replacement to a standard anterior cervical fusion with results up to 2 years. PURPOSE: The purpose of this study is to examine the initial functional outcome results of this prospective, randomized trial to determine the role of the Bryan artificial cervical disc replacement compared with fusion for patients with a cervical disc herniation or stenosis causing radiculopathy. STUDY DESIGN/SETTING: The data from 3 surgeons involved in the FDA IDE trial of the Bryan cervical disc replacement were evaluated. This is a multicenter prospective, randomized study of patients with cervical radiculopathy or myelopathy due to one level cervical stenosis or disc herniation. The control population is anterior cervical fusion with allograft and a plate. Randomization ratio is 1:1. PATIENT SAMPLE: 115 patients were randomized in a 1:1 ratio to a Bryan artificial disc replacement (56) or an anterior cervical fusion with allograft and a plate (59). There were 30 males and 26 females in the Bryan group and 32 males and 27 females in the fusion group. The average age was 43 years (Bryan) and 46 years (fusion). OUTCOME MEASURES: Neck Disability Index (NDI) Neck pain visual analog pain score (VAS) Arm pain visual analog pain score (VAS) SF-36physical component: (PCS) mental component: (MCS) Range of Motion (ROM) flexion/extension. METHODS: Patients were prospectively evaluated preoperatively as well as at defined intervals postoperatively. RESULTS: The average operative time for the control group was 1.1 hours and the Bryan group 1.7 hours. Average blood loss was 50 cc (control) and
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
89S
66cc (Bryan). Average hospital stay was 0.5 days (control) and 1 day (Bryan). Neck Disability Index score (NDI) preoperatively was 47 (Bryan) and 49 (control). 12 month follow-up data are available for 75 patients (38 Bryan and 37 controls) with NDI 11 (Bryan) and 19 (control). At 2-year follow-up 16 patients are available (8 Bryan and 8 control) NDI for the Bryan group is 7 and control group 26. Arm pain VAS preoperatively was 70 (Bryan) and 71 (control). At 1-year follow-up Bryan arm pain VAS was 14 and control 22. At 2-year follow-up the average arm pain VAS for the Bryan group was 7 and control 45. Neck pain VAS preoperatively was 72 (Bryan) and 73 (control). 1-year follow-up scores were 19 (Bryan) and 28 (control). At 2-years: 10 (Bryan) and 38 (control). SF-36 scores: Physical component- Preoperatively Bryan-34 and control 32. At 24-months: Bryan51 and control-45. Mental component preoperatively: Bryan 46 and control 49. At 24-months: Bryan-55 and control-50. As expected, significantly (p⬍.006 at 3, 6, and 12 months) more motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 6.7 degrees at 12 months. In contrast, the average range of motion in the fusion group was 2.0 degrees at the threemonth follow-up and gradually decreased to 0.6 degrees at 24 months. CONCLUSIONS: The Bryan artificial disc replacement compares very favorable to a conventional anterior cervical fusion for the treatment of patients with cervical radiculopathy. DISCLOSURES: FDA device/drug: Bryan artificial disc. Status: Investigational/not approved. FDA device/drug: allograft bone. Status: Approved for this indication. FDA device/drug: anterior cervical plate. Status: Approved for this indication. CONFLICT OF INTEREST: Author (RS) Consultant: Medtronic.
groups was statistically significantly. Patient satisfaction and SF-36 PCS domain also improved significantly in the IPD group compared with controls. No differences between groups in SF-36 MCS scores and in percent slippage after 2 years were present. Postoperatively, the results were stable over all time periods. Overall clinical success, defined as a minimum 15% improvement in ZCQ and absence of further surgical treatment, was 69% in IPD compared with 9% in controls. This difference was statistically significant.
doi: 10.1016/j.spinee.2005.05.174
F/U⫽follow-up; IPD⫽interspinous process decompression; PCS⫽ Physical Component Summary; ZCQ⫽Zurich Claudication Questionnaire.
Friday, September 30, 2005 6:00–7:00 PM SIPP 2: Novel Technology 6:00 172. Interspinous process decompression (IPD) of patients with neurogenic intermittent claudication secondary to degenerative spondylolisthesis Paul Anderson, MD1, Scott Kitchell, MD2; 1University of WisconsinMadison, Madison, WI, USA; 2NASS, Eugene, OR, USA BACKGROUND CONTEXT: Interspinous process decompression (IPD) theoretically prevents narrowing of the spinal canal and neuroforamina in extension, and thus reduces the symptoms of neurogenic intermittent claudication (NIC). PURPOSE: The purpose of this study was to compare the outcomes of degenerative spondylolisthesis patients treated with the IPD technique to those treated nonoperatively. STUDY DESIGN/SETTING: Randomized controlled trial. PATIENT SAMPLE: 61 patients with neurogenic claudication secondary to degenerative sponylolisthesis at 1 or 2 levels. OUTCOME MEASURES: The validated stenosis-specific Zurich Claudication Questionnaire (ZCQ) range 0–100, SF-36, patient satisfaction, and by lumbar radiographs. Assessments were preoperative, 3, 6, 12, and 24 months. METHODS: An FDA-approved prospective randomized multi-center IDE study with 191 NIC patients included 61 patients with up to Grade I degenerative spondylolisthesis; 39 were treated with IPD (X STOP) and 22 nonoperatively with epidural steroids. The validated, stenosis-specific Zurich Claudication Questionnaire (ZCQ), range 0–100, was administered preoperatively and at 3, 6, 12, and 24 months. Also results were assessed by SF-36, patient satisfaction, and by radiographs. Statistical analysis between groups was by ANOVA. RESULTS: At 2 years, the IPD group improved in ZCQ from 51 to 24 compared with 49 to 50 in the controls (Table 1). The difference between
Table 1 Overall results Control Number of patients ZCQ (0–100) Preop F/U Patient satisfaction Range (0–100) SF-36 PCS Preop F/U Percent slip Number of levels Preop F/U Overall clinical success
IPD
p value
22
39
48.9 (14.7) 50.5 (21.5)
51.2 (12.7) 25.2 (20.2)
⬍0.0001
56.9 (35.40)
21.7 (29.1)
⬍0.0001
29.1 (7.0) 31.6 (8.7)
28.1 (6.4) 40.4 (13.3)
⬍0.0001
27 12.7 (8.9) 11.8 (12.7) 9.1%
53 9.97 (7.5) 11.0 (9.3) 69.2%
⬍0.0001 ⬍0.0001
CONCLUSIONS: The results of the current study demonstrate that interspinous process decompression via the X STOP is more effective in NIC patients with up to Grade I degenerative spondylolisthesis compared with nonoperative treatment. This technique maintainns motion and does not require fusion. Also spondylolisthesis is unchanged after IPD. DISCLOSURES: FDA device/drug: Xstop. Status: Investigational/not approved. CONFLICT OF INTEREST: Author (PA) Consultant: St. Francis Medical Technologies. doi: 10.1016/j.spinee.2005.05.175
6:06 173. Dynamic stabilization of the degenerative lumbar motion segment: the Wallis system Nicholas Boeree, MD; Southampton University Hospital, Hants, United Kingdom BACKGROUND CONTEXT: The Wallis implant was conceived to increase the stiffness of the degenerative segment in order to counterbalance changes related to degenerative disc disease (DDD). The Wallis implant evolved from successful clinical experience in over 300 patients with a first generation implant, supported by detailed biomechanical and finite element studies. PURPOSE: The purpose of the present ongoing study is to demonstrate the safety and effectiveness of this second generation implant against low back pain and functional disability in patients with degenerative disc disease. STUDY DESIGN/SETTING: This study was a prospective, multicenter and open study conducted in 8 centers in 6 countries. PATIENT SAMPLE: 260 consecutive patients (39% female, 61% male) with a mean age of 44 years were treated with Wallis. 37% patients had a principal diagnosis of massive disc herniation, 27% had DDD with Modic type 1 change, 13% had canal stenosis, 9% had recurrence of disc herniation and 5% had L5 sacralization with herniation of the transitional disc.