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P36. Characterization of graft subsidence in anterior cervical discectomy and fusion with rigid anterior plate fixation yielding high fusion rate and good clinical outcome
72S
Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S
methodology of these publications obviate the formulation of any judgment concerning their success. PURPOSE: To report the effectiveness and side effects following percutaneous disc decompression using coblation technology combined with a selective nerve root injection (SNRI) to treat cervical radiculopathy. STUDY DESIGN/SETTING: Prospective, University Hospital. PATIENT SAMPLE: Consecutive patients. OUTCOME MEASURES: Visual analog scale (VAS). Twenty-two potential side effects were monitored. METHODS: Consecutive patients were prospectively enrolled. Inclusion criteria were arm greater than neck pain; corroborative focal protrusion on MRI; a minimum of a corroborative myotomal deficit, positive electrodiagnostic study or positive diagnostic root block; failure of oral anti-inflammatory medication, physical therapy and/or imminent surgery. Patients were excluded with a focal protrusion over 5mm. Side effects were assessed at 6 predetermined postoperative intervals through 2 weeks. Outcomes were assessed using a visual analog scale (VAS) preoperatively and at 2 weeks, 1, 2, 3 and 6 months postoperatively. Each subject was reviewed by a spine surgeon to determine if they were a potential operable candidate. Data collection was performed by an independent reviewer. Statistical analyses were accomplished using McNemar’s and the Wilcoxon signed rank test. RESULTS: Each of the 21 patients, ranging in age from 28 to 54, with an average symptom duration of 36 weeks, was considered a potential surgical candidate by a fellowship trained spine surgeon. Mean preoperative VAS was 6.9 (range 4–9). Mean serial follow-up interval VAS rating was: 2.9 (range 0–7.7; 3 with no pain) in 21 pts at 2 w; 2.1 (range 0–6.7; 11 with no pain) in 21pts at 4w; 1.7 (range 0–6.8: 12 with no pain) in 21 pts at 8 w; 1.2 (range 0–6; 8 with no pain) in 21 pts at 3 m; and 1.3 (range 0–8; 7 with no pain; 5 with VAS of 1; 3 VAS of 2) in 19 pts at 6mo. There was a statistically significant reduction in the VAS rating at each follow-up (p⬍.0001). As well, there were clinically significant reductions in the VAS rating; mean percentage reduction of 58, 70, 75, 83, and 81 at the respective serial follow-ups for the entire population (failures and successes). There were no significant early term side effects. One patient underwent successful surgery between 8 and 12 weeks post-procedure. One patient underwent repeat disc decompression and snri between 3 and 6 months post-procedure. CONCLUSIONS: This novel approach for the treatment of cervical radiculopathy merits further scientific investigation as 91–95% (19 or 20 of 21) of patients were successfully treated without any significant side effects. The outcome rate, rapid slope of symptom resolution, stability of response and high frequency of complete arm pain resolution is superior to selective nerve root block alone and approximates open surgery. DISCLOSURES: Device or drug: Coblation catheter or nucleoplasty. Status: Approved for this indication. CONFLICT OF INTEREST: Author (CS) Arthrocare; Author (CS) Stockholder: Arthrocare; Author (CS) Grant Research Support: Nucleus pulposus coblation: in vitro effects on disc mechanics” Objective: Determine the effect of nucleus pulposus coblation on disc mechanical behavior (3/ 1/02–2/28/03) pending support for research involviing unrelated technology. doi: 10.1016/j.spinee.2004.05.142 P36. Characterization of graft subsidence in anterior cervical discectomy and fusion with rigid anterior plate fixation yielding high fusion rate and good clinical outcome Dino Samartzis, BS1, Rex A.W. Marco, MD2, Louis Jenis, MD3, Nitin Khanna, MD4, Robert Banco, MD3, Edward J. Goldberg, MD5, Howard S An, MD5; 1Harvard University & The University of Oxford, Chicago, IL, USA; 2University of Texas Health Science Center at Houston, Houston, TX, USA; 3Boston Spine Group, New England Baptist Hospital, Boston, MA, USA; 4Orthopaedic Specialists of Northwest Indiana, Munster, IN, USA; 5Department of Orthopaedic Surgery, Rush Medical College, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, IL, USA
BACKGROUND CONTEXT: Graft subsidence in interbody fusion can occur in patients following anterior cervical discectomy and fusion (ACDF) with or without plating. Dynamic plate fixation systems were introduced in recent years to accommodate the postoperative subsidence and to provide load sharing between the graft and the plate. On the other hand, rigid anterior plate fixation is believed to prevent subsidence and the load-sharing mechanism, but generally is associated with high overall fusion rates in the literature. In the literature, postoperative subsidence following ACDF with rigid anterior plate fixation has not been well defined. PURPOSE: To determine the characteristics of subsidence, evaluate fusion rate, and assess clinical outcome in patients who underwent ACDF with rigid anterior cervical plate fixation. STUDY DESIGN/SETTING: Radiographic and clinical review of 32 patients who underwent ACDF with rigid anterior plate fixation. PATIENT SAMPLE: Thirty-two consecutive ACDF patients (9 one-level, 19 two-levels, and 4 three-levels) were blindly reviewed for clinical and radiographic data. A Smith-Robinson technique was utilized in all patients (19 autograft, 13 allograft). Rigid anterior plate fixation was utilized in all cases. Soft collars were worn postoperatively for 3–4 weeks. Eleven patients reported tobacco use. OUTCOME MEASURES: An independent blinded observer assessed fusion, instrumentation integrity, clinical outcome, and subsidence. Postoperative to a minimum of 1-year last follow-up radiographs (mean, 18 months) were evaluated and compared. Radiographs were used to determine subsidence on lateral neutral images by measuring in millimeters change in height of interscrew distance (ISD) and anterior (AVD), mid (MVD), and posterior (PVD) vertebral endplate to endplate vertical distances. Late subsidence was defined as postoperative graft settling at a minimum of two months and greater. Clinical outcome (mean, 23 months) was rated based on Odom’s criteria. METHODS: Radiographs, medical records, and outcome scores were assessed. Statistical significance was established at p⬍0.05. RESULTS: All patients achieved fusion and no instrumentation-related complications were noted. Clinical outcome demonstrated 5 excellent, 25 good, and 2 patients with fair results. Mild subsidence was noted in every patient. The mean AVD was 1.23 mm (range, 0.00 to 3.00 mm). Mean MVD and PVD were 0.42 mm (range, 0.00 to 2.00 mm) and 0.65 mm (range, 0.00 to 3.50 mm), respectively. ISD was noted at a mean of 0.58 mm (range, 0.00 to 2.00 mm). Percent change for AVD, MVD, PVD, and ISD was noted to be 2.3%, 0.8%, 1.2%, and 1.2%, respectively (range, 0.00 to 7.10%). Subsidence was more pronounced anteriorly (p⬍0.05). Age, sex, smoking status, plate design, graft-type, and operative or number of fused levels did not demonstrate statistically significant differences in the degree of subsidence. CONCLUSIONS: A 100 % fusion rate was achieved and mild graft subsidence was noted to occur in every patient. Subsidence was more prevalent anteriorly and satisfactory clinical results were reported in 90.9% of the patients in this series. Late subsidence was noted in every patient following the initial two months of surgery. This study demonstrates that minimal subsidence (mean, 1.23 mm) does occur in ACDF with rigid anterior plate fixation and the combination of mild subsidence, graft loading, and rigid stabilization of the motion segments probably is in part responsible for the high fusion rate, good clinical outcome, and no instrumentation-related complications. DISCLOSURES: Device or drug: Anterior cervical plates. Status: Approved for this indication. CONFLICT OF INTEREST: Author (HSA) Stockholder: Depuy Spine doi: 10.1016/j.spinee.2004.05.143 P31. Dynamic stabilization of degenerative lumbar spondylolisthesis Thomas Stoll1, Gilles Dubois2, Othmar Schwarzenbach3; 1Bethesda Spital Basel Switzerland, Basel, Switzerland; 2Clinique de l’Union, France; 3Spital Thun-Simmental, Switzerland BACKGROUND CONTEXT: This prospective multi-center study evaluates the safety and efficacy of a dynamic non-fusion stabilization system in the treatment of lumbar degenerative spondylolisthesis.
Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S
methodology of these publications obviate the formulation of any judgment concerning their success. PURPOSE: To report the effectiveness and side effects following percutaneous disc decompression using coblation technology combined with a selective nerve root injection (SNRI) to treat cervical radiculopathy. STUDY DESIGN/SETTING: Prospective, University Hospital. PATIENT SAMPLE: Consecutive patients. OUTCOME MEASURES: Visual analog scale (VAS). Twenty-two potential side effects were monitored. METHODS: Consecutive patients were prospectively enrolled. Inclusion criteria were arm greater than neck pain; corroborative focal protrusion on MRI; a minimum of a corroborative myotomal deficit, positive electrodiagnostic study or positive diagnostic root block; failure of oral anti-inflammatory medication, physical therapy and/or imminent surgery. Patients were excluded with a focal protrusion over 5mm. Side effects were assessed at 6 predetermined postoperative intervals through 2 weeks. Outcomes were assessed using a visual analog scale (VAS) preoperatively and at 2 weeks, 1, 2, 3 and 6 months postoperatively. Each subject was reviewed by a spine surgeon to determine if they were a potential operable candidate. Data collection was performed by an independent reviewer. Statistical analyses were accomplished using McNemar’s and the Wilcoxon signed rank test. RESULTS: Each of the 21 patients, ranging in age from 28 to 54, with an average symptom duration of 36 weeks, was considered a potential surgical candidate by a fellowship trained spine surgeon. Mean preoperative VAS was 6.9 (range 4–9). Mean serial follow-up interval VAS rating was: 2.9 (range 0–7.7; 3 with no pain) in 21 pts at 2 w; 2.1 (range 0–6.7; 11 with no pain) in 21pts at 4w; 1.7 (range 0–6.8: 12 with no pain) in 21 pts at 8 w; 1.2 (range 0–6; 8 with no pain) in 21 pts at 3 m; and 1.3 (range 0–8; 7 with no pain; 5 with VAS of 1; 3 VAS of 2) in 19 pts at 6mo. There was a statistically significant reduction in the VAS rating at each follow-up (p⬍.0001). As well, there were clinically significant reductions in the VAS rating; mean percentage reduction of 58, 70, 75, 83, and 81 at the respective serial follow-ups for the entire population (failures and successes). There were no significant early term side effects. One patient underwent successful surgery between 8 and 12 weeks post-procedure. One patient underwent repeat disc decompression and snri between 3 and 6 months post-procedure. CONCLUSIONS: This novel approach for the treatment of cervical radiculopathy merits further scientific investigation as 91–95% (19 or 20 of 21) of patients were successfully treated without any significant side effects. The outcome rate, rapid slope of symptom resolution, stability of response and high frequency of complete arm pain resolution is superior to selective nerve root block alone and approximates open surgery. DISCLOSURES: Device or drug: Coblation catheter or nucleoplasty. Status: Approved for this indication. CONFLICT OF INTEREST: Author (CS) Arthrocare; Author (CS) Stockholder: Arthrocare; Author (CS) Grant Research Support: Nucleus pulposus coblation: in vitro effects on disc mechanics” Objective: Determine the effect of nucleus pulposus coblation on disc mechanical behavior (3/ 1/02–2/28/03) pending support for research involviing unrelated technology. doi: 10.1016/j.spinee.2004.05.142 P36. Characterization of graft subsidence in anterior cervical discectomy and fusion with rigid anterior plate fixation yielding high fusion rate and good clinical outcome Dino Samartzis, BS1, Rex A.W. Marco, MD2, Louis Jenis, MD3, Nitin Khanna, MD4, Robert Banco, MD3, Edward J. Goldberg, MD5, Howard S An, MD5; 1Harvard University & The University of Oxford, Chicago, IL, USA; 2University of Texas Health Science Center at Houston, Houston, TX, USA; 3Boston Spine Group, New England Baptist Hospital, Boston, MA, USA; 4Orthopaedic Specialists of Northwest Indiana, Munster, IN, USA; 5Department of Orthopaedic Surgery, Rush Medical College, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, IL, USA
BACKGROUND CONTEXT: Graft subsidence in interbody fusion can occur in patients following anterior cervical discectomy and fusion (ACDF) with or without plating. Dynamic plate fixation systems were introduced in recent years to accommodate the postoperative subsidence and to provide load sharing between the graft and the plate. On the other hand, rigid anterior plate fixation is believed to prevent subsidence and the load-sharing mechanism, but generally is associated with high overall fusion rates in the literature. In the literature, postoperative subsidence following ACDF with rigid anterior plate fixation has not been well defined. PURPOSE: To determine the characteristics of subsidence, evaluate fusion rate, and assess clinical outcome in patients who underwent ACDF with rigid anterior cervical plate fixation. STUDY DESIGN/SETTING: Radiographic and clinical review of 32 patients who underwent ACDF with rigid anterior plate fixation. PATIENT SAMPLE: Thirty-two consecutive ACDF patients (9 one-level, 19 two-levels, and 4 three-levels) were blindly reviewed for clinical and radiographic data. A Smith-Robinson technique was utilized in all patients (19 autograft, 13 allograft). Rigid anterior plate fixation was utilized in all cases. Soft collars were worn postoperatively for 3–4 weeks. Eleven patients reported tobacco use. OUTCOME MEASURES: An independent blinded observer assessed fusion, instrumentation integrity, clinical outcome, and subsidence. Postoperative to a minimum of 1-year last follow-up radiographs (mean, 18 months) were evaluated and compared. Radiographs were used to determine subsidence on lateral neutral images by measuring in millimeters change in height of interscrew distance (ISD) and anterior (AVD), mid (MVD), and posterior (PVD) vertebral endplate to endplate vertical distances. Late subsidence was defined as postoperative graft settling at a minimum of two months and greater. Clinical outcome (mean, 23 months) was rated based on Odom’s criteria. METHODS: Radiographs, medical records, and outcome scores were assessed. Statistical significance was established at p⬍0.05. RESULTS: All patients achieved fusion and no instrumentation-related complications were noted. Clinical outcome demonstrated 5 excellent, 25 good, and 2 patients with fair results. Mild subsidence was noted in every patient. The mean AVD was 1.23 mm (range, 0.00 to 3.00 mm). Mean MVD and PVD were 0.42 mm (range, 0.00 to 2.00 mm) and 0.65 mm (range, 0.00 to 3.50 mm), respectively. ISD was noted at a mean of 0.58 mm (range, 0.00 to 2.00 mm). Percent change for AVD, MVD, PVD, and ISD was noted to be 2.3%, 0.8%, 1.2%, and 1.2%, respectively (range, 0.00 to 7.10%). Subsidence was more pronounced anteriorly (p⬍0.05). Age, sex, smoking status, plate design, graft-type, and operative or number of fused levels did not demonstrate statistically significant differences in the degree of subsidence. CONCLUSIONS: A 100 % fusion rate was achieved and mild graft subsidence was noted to occur in every patient. Subsidence was more prevalent anteriorly and satisfactory clinical results were reported in 90.9% of the patients in this series. Late subsidence was noted in every patient following the initial two months of surgery. This study demonstrates that minimal subsidence (mean, 1.23 mm) does occur in ACDF with rigid anterior plate fixation and the combination of mild subsidence, graft loading, and rigid stabilization of the motion segments probably is in part responsible for the high fusion rate, good clinical outcome, and no instrumentation-related complications. DISCLOSURES: Device or drug: Anterior cervical plates. Status: Approved for this indication. CONFLICT OF INTEREST: Author (HSA) Stockholder: Depuy Spine doi: 10.1016/j.spinee.2004.05.143 P31. Dynamic stabilization of degenerative lumbar spondylolisthesis Thomas Stoll1, Gilles Dubois2, Othmar Schwarzenbach3; 1Bethesda Spital Basel Switzerland, Basel, Switzerland; 2Clinique de l’Union, France; 3Spital Thun-Simmental, Switzerland BACKGROUND CONTEXT: This prospective multi-center study evaluates the safety and efficacy of a dynamic non-fusion stabilization system in the treatment of lumbar degenerative spondylolisthesis.