- Email: [email protected]
P92. Minimum one year results of the PRODISC II lumbar total disc replacement
140S
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
P82. Anterior versus posterior spinal instrumentation for the treatment of thoracolumbar curves in adolescent idiopathic scoliosis David L. Skaggs1, Lauren Friend1, Kasey Cortese1, George Bassett1, Sean D. Early1, Vernon T. Tolo1; 1Childrens Hospital of Los Angeles, Los Angeles, CA, USA HYPOTHESIS: Thoracolumbar curves in adolescent idiopathic scoliosis may be treated surgically with anterior or posterior spinal instrumentation, with little evidence in the literature to suggest superiority of either technique. The purpose of this study is to compare anterior vs. posterior instrumentation in a well-defined population of patients with adolescent idiopathic scoliosis with thoracolumbar scoliosis. METHODS: Medical records and radiographs of all patients undergoing spinal instrumentation for the treatment of adolescent idiopathic scoliosis with primary thoracolumbar curves, defined as curve apices between T10 and L2, between 1993 and 2001 were reviewed. The study group consists of 12 patients treated with anterior spinal instrumentation and 16 with posterior instrumentation. Various radiographic and outcome measures were compared between groups. RESULTS: The anterior group had 75% correction of the primary Cobb angle compared to 56% in the posterior group (p⫽0.019). An average of 3.8 vertebral levels in the anterior and 6.7 in the posterior procedures were fused (P⬍0.001). Less blood loss was observed in the anterior group (p⫽0.007), with fewer transfusions as well (P⬍0.001). The anterior group produced more lumbar lordosis (p⫽0.03) than the posterior group. In the anterior group there was a 0% rate of revision surgery (0/12) where as the posterior group had a 31% revision rate (5/16) which was a significant difference (p⫽0.047). DISCUSSION: This study comparing anterior versus posterior instrumentation is unique in that it is limited to thoracolumbar curves. While earlier series of anterior instrumentation revealed high rates of hardware failure and pseudoarthrosis, this series found no instance of either in the anterior group. In addition, concern over anterior compression instrumentation causing kyphosis proved unwarranted. In fact, the anterior instrumented group had improved lumbar lordosis compared to the posterior. CONCLUSIONS: In thoracolumbar idiopathic curves, anterior instrumentation had a significantly improved Cobb angle, less levels fused, and more lumbar lordosis, and less blood transfusions when compared to posterior instrumentation. In addition, patients undergoing anterior instrumentation had a significantly lower rate of revision surgery compared to those with posterior instrumentation. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00333-4 P87. Patterns and trends of opioid use among individuals with back pain in the U.S. Xuemei Luo, PhD1, Ricardo Pietrobon, MD1, Lloyd Hey, MD1; 1Duke University Medical Center, Durham, NC, USA HYPOTHESIS: There is variation on opioid use among individuals with back pain who had different demographic, socioeconomic characteristics and from different geographic regions. From 1996 to 1999, overall use of opioid among individuals with back pain was not dramatically changed but the use of specific opioid may increase or decrease. METHODS: This study used the data from 1996 to 1999 Medical Expenditure Panel Survey, a national survey database on health care utilization and expenditures. Patterns of opioid use were examined by stratifying individuals with back pain by demographic, socioeconomic characteristics and geographical regions, and comparing the rate of opioid use during each of the four years (1996–1999) among the different strata. Trends of opioid use were assessed by comparing the rate of overall and specific opioid use across the four-year span. RESULTS: Several consistent or evolving patterns on opioid use were observed among individuals with back pain from 1996 to 1999. For each of the four years, there was no difference in opioid use according to sex and
ethnicity but the use of opioid was significantly higher among individuals who were publicly insured, had low or below low income and had education at or below 12th grade than their respective counterparts. Significant variations in opioid use according to age or region were observed in early years and became non-significant in later years. Rates of overall opioid use slightly increased from 1996 to 1999. Among individual opioid categories, the use of oxycodone or hydrocodone increased whereas the use of propoxyphene decreased across the 4-year span. DISCUSSION: To our knowledge, this is the first study to examine at the national level the patterns and trends of opioid use among individuals with back pain in the US. CONCLUSIONS: Our study indicated several consistent or evolving patterns and some interesting trends on opioid use among individuals with back pain in the US. Most notably, the overall use of opioid was significantly higher among individuals who were publicly insured, had low or below low income and had education at or below 12th grade than their respective counterparts. The use of two specific opioid, oxycodone and hydrocodone, demonstrated increasing trends from 1996 to 1999. Because Opioid can have serious side effects, has the potential for addition and there is a lack of scientifically sound studies about its efficacy for back pain, the significantly higher use of opioid among individuals who were publicly insured, had low or below low income and had education at or below 12th grade raises serious concerns about drug safety among these people. More studies are needed to understand why these individuals were more likely to use opioid and what outcomes are associated with this higher usage. Future studies are also needed to examine the efficacy and safety of specific opioid, especially those that demonstrated increasing trends of use during recent years, among individuals with back pain. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00334-6
P92. Minimum one year results of the PRODISC II lumbar total disc replacement Patrick Tropiano, MD1, Russel Huang, MD2, Federico Girardi, MD2, Thierry Marnay, MD3; 1Hoˆpital CHU Nord, Marseille, France; 2 Hospital for Special Surgery, New York, NY, USA; 3Clinique du Parc, Castelnau Le Lez, France HYPOTHESIS: We hypothesized that lumbar total disc replacement (TDR) with the PRODISC II prosthesis would result in clinically and statistically significant improvement in low back pain, radicular leg pain, and disability in patients with symptomatic degenerative disc disease who had failed nonsurgical treatment. METHODS: We prospectively assessed 53 patients who had single or multilevel lumbar disc replacement with the PRODISC II TDR at mean 1.4-year (range 1–2) follow-up. There were 18 men and 35 women with a mean age of 45 years (range 28–67). Preoperative diagnoses included disc degeneration (33 patients) and failed spine surgery (20 patients), and all patients had at least 6 months of severe back pain and had failed nonsurgical treatment. Exclusion criteria included facet arthrosis, central or lateral recess stenosis, osteoporosis, deficiency of posterior elements (laminae or facets), and sagittal or coronal plane deformity. Patient evaluation consisted of pre- and postoperative back and leg pain VAS scores, Oswestry disability questionnaires, and radiographs. Clinical evaluation and questionnaire administration was performed by individuals not directly involved in patient selection, surgery, or postoperative care. RESULTS: There were clinically and statistically significant improvements in back and leg pain VAS and Oswestry disability scores that were maintained at final follow-up. Mean lumbar VAS decreased from 7.4 to 1.3 at final follow-up. Mean radicular VAS decreased from 6.7 to 1.9. Oswestry disability scores improved from 56 to 14. VAS and Oswestry improvements were statistically significant (p⬍0.05). The clinical results of patients with single and multilevel surgery were equivalent. Satisfactory results were achieved in 90% of patients who had previous lumbar surgery. Mean
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
141S
flexion-extension range of motion of implants was 8 degrees (range 2–12) at L5-S1 and 10 degrees (range 8–18) at L4-L5. Complications occurred in 9% of patients and included vertebral body fracture, transient radicular pain, implant malposition, and transient retrograde ejaculation. Three patients (6%) required reoperation to address complications. No mechanical failure of the implants or loosening was observed. DISCUSSION: Total disc replacement has the potential to replace fusion as the gold standard surgical treatment for degenerative disc disease. Potential advantages of TDR over fusion include avoidance of pseudarthosis, postoperative orthoses, and junctional degeneration. There are no published studies with minimum 1-year follow-up of the PRODISC II prosthesis. Longerterm follow-up of the SB Charite´ prosthesis has been reported, but there are significant biomechanical differences between the two implants, especially with regard to kinematics and constraint. Randomized trials comparing fusion to disc replacement and comparing different TDR implants with long follow-up periods are required to determine to relative merits of the various procedures and implants. CONCLUSIONS: In properly selected patients, lumbar TDR with the PRODISC II has excellent clinical and radiographic results at mean 1.4year follow-up. Patients with single or multilevel degenerative disc disease are candidates for this procedure. Implant malposition and intra-operative fracture resulted in a 6% reoperation rate. DISCLOSURES: Device or drug: PRODISC II lumbar disc replacement. Status: investigational. CONFLICT OF INTEREST: Federico Girardi, MD, Thierry Marnay, MD, stockholders: Spine Solutions, Inc. Thierry Marnay, MD, grant research support: for research staff; board member: Spine Solutions, Inc.
good results, 8.5% reported fair results, and 1.1% reported poor results. In group 2, 28% of the patients reported excellent results, 62% reported good results, and 10% reported fair results. All nonunions reported good outcomes. Postoperative respiratory distress developed in one patient and dysphagia developed in another both from group 1. No other complications were noted. The presence or absence of direct uncovertebral joint decompression and clinical outcome was not statistically significant (p⬎0.05). The use of graft-type, operative level, presence of smoking, and work-related injury in relation to clinical outcome was not found to be significant. DISCUSSION: Satisfactory results were obtained in 90.5% and 90.0% of patients for groups 1 and 2, respectively. Good to excellent results in relieving neck pain and radicular symptoms were obtained in 90% of patients who underwent direct uncovertebral joint decompression and in patients with indirect decompression by distraction and leaving the uncovertebral joint intact. CONCLUSIONS: Indirect foraminal decompression through distraction remains somewhat controversial during ACDF, however sacrificing the uncovertebral joint can increase operative time and potentially increase complication rates. This study demonstrates that ACDF with or without direct uncovertebral joint decompression can provide good clinical results for neck pain with cervical radiculopathy. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts.
doi: 10.1016/S1529-9430(03)00335-8
P102. Multidirectional stability of a dynamic stabilization system over graf ligamentoplasty: the effect of various posterior stabilizing implants Osamu Shirado, MD1, Yoshihiro Hojo, MD1, Akio Minami, MD1; 1 Hokkaido University, Sapporo, Japan
P97. Clinical outcome in patients undergoing anterior cervical discectomy and fusion with or without direct uncovertebral joint decompression Francis Shen, MD1, Dino Samartzis1, Edward Goldberg1, Howard An1; 1Rush-Presbyterian-St. Luke’s Medical Center/Rush University, Chicago, IL, USA HYPOTHESIS: Anterior cervical discectomy and fusion (ACDF) is an established procedure for the treatment of cervical disc disease. Studies demonstrate that in patients with radiculopathy secondary to impingement from uncovertebral joint osteophytes, direct decompression of the offending lesion provides excellent clinical outcome. However known complications include vertebral artery injury, dural tears, nerve root injury, and loss of biomechanical stability. Other studies suggest that disc space distraction may also play an important role by indirectly decompressing neural elements. We hypothesis that patients the undergo ACDF without direct uncovertebral joint decompression will have similar clinical outcomes to those that undergo ACDF with direct decompression. METHODS: Clinical outcome of 144 consecutive patients (mean 46 years, range 27–83) that underwent ACDF with constrained plate fixation were reviewed at a single institution. Patients with radiculopathy due to herniated disc, spondylosis, or a combination of both refractory to conservative treatment underwent surgery utilizing a standard Smith-Robinson left-sided approach. Ninety-four patients that received direct uncovertebral joint decompression (group 1) were compared to 50 patients without direct decompression but indirect decompression by disc space distraction (group 2). In group 1, 54 one-level and 40 two-level ACDFs were performed. In group 2, 18 and 32 were one-level and two-level ACDFs respectively. The presence of smoking and work-related injuries involved 32.9% and 43.6% of group 1 and 26% and 32% of group 2, respectively. Autologous iliac crest grafts was used in 65 patients, while 79 patients received allograft. Blinded analyses of plain radiographs were conducted (mean, 9.2 months). Clinical outcomes were reported as excellent, good, fair or poor (mean, 15 months) based on Odom’s criteria. RESULTS: Fusion occurred in 95.7% of group 1 and 100% of group 2. In group 1, 27.7% of the patients reported excellent results, 62.8% reported
doi: 10.1016/S1529-9430(03)00336-X
HYPOTHESIS: An expected advantage of Graf ligamentoplasty over spinal fusion is the decrease risk of adjacent-segment morbidity by stabilizing unstable segments without requiring rigid spinal arthrodesis. However, it remains controversial whether the Graf system can be rigid enough to stabilize an unstable spine. Thus, refinement of the Graf system has recently been highlighted in the literature. The purpose of this study was to biomechanically evaluate multidirectional stability of the dynamic stabilization systems using various posterior stabilizing implants. We hypothesized that this system could provide the multidirectional stability for unstable lumbar spines. METHODS: Twelve fresh calf lumbar spine specimens (L2-sacrum) were subjected to compression (100 N), flexion and extension (5 N-m), lateral bending (5 N-m), and rotation (10 N-m). The load-displacement curves were simultaneously measured. Testing of the intact spine preceded testing of the L4-5 destabilized spine (performed by bilateral medial facetectomies), and in each of the following stabilizing treatment groups: Graf ligamentoplasty, Graf with posterior titanium springs between the pedicle screws, Graf with an interspinous coiled artificial ligament, Graf with an interspinous ceramic spacer, and a rigid pedicle screw system. Extensometers were applied to measure the strain in the stabilized (L4-5) and adjacent segments (L3-4). Statistical analysis was carried out using one-way ANOVA. RESULTS: In the flexion and compression, the strain at L4-5 was not significantly different among all the stabilized constructs except the rigid pedicle screw system. During extension, lateral bending, and rotation, Graf ligamentoplasty enhanced with the various posterior implants were more stable than Graf ligamentoplasty alone (p⬍0.05). The construct enhanced with the ceramic spacer was the most stable of the treatment groups (p⬍.05). The posteriorly enhanced systems were more flexible than the rigid pedicle screw system. Furthermore, the strain at the adjacent segment (L3-4) in the posteriorly enhanced constructs was significantly lower than using the rigid pedicle screw system. DISCUSSION: The current study demonstrates that the Graf ligamentoplasty can provide a multi-directional dynamic stabilization for the
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
P82. Anterior versus posterior spinal instrumentation for the treatment of thoracolumbar curves in adolescent idiopathic scoliosis David L. Skaggs1, Lauren Friend1, Kasey Cortese1, George Bassett1, Sean D. Early1, Vernon T. Tolo1; 1Childrens Hospital of Los Angeles, Los Angeles, CA, USA HYPOTHESIS: Thoracolumbar curves in adolescent idiopathic scoliosis may be treated surgically with anterior or posterior spinal instrumentation, with little evidence in the literature to suggest superiority of either technique. The purpose of this study is to compare anterior vs. posterior instrumentation in a well-defined population of patients with adolescent idiopathic scoliosis with thoracolumbar scoliosis. METHODS: Medical records and radiographs of all patients undergoing spinal instrumentation for the treatment of adolescent idiopathic scoliosis with primary thoracolumbar curves, defined as curve apices between T10 and L2, between 1993 and 2001 were reviewed. The study group consists of 12 patients treated with anterior spinal instrumentation and 16 with posterior instrumentation. Various radiographic and outcome measures were compared between groups. RESULTS: The anterior group had 75% correction of the primary Cobb angle compared to 56% in the posterior group (p⫽0.019). An average of 3.8 vertebral levels in the anterior and 6.7 in the posterior procedures were fused (P⬍0.001). Less blood loss was observed in the anterior group (p⫽0.007), with fewer transfusions as well (P⬍0.001). The anterior group produced more lumbar lordosis (p⫽0.03) than the posterior group. In the anterior group there was a 0% rate of revision surgery (0/12) where as the posterior group had a 31% revision rate (5/16) which was a significant difference (p⫽0.047). DISCUSSION: This study comparing anterior versus posterior instrumentation is unique in that it is limited to thoracolumbar curves. While earlier series of anterior instrumentation revealed high rates of hardware failure and pseudoarthrosis, this series found no instance of either in the anterior group. In addition, concern over anterior compression instrumentation causing kyphosis proved unwarranted. In fact, the anterior instrumented group had improved lumbar lordosis compared to the posterior. CONCLUSIONS: In thoracolumbar idiopathic curves, anterior instrumentation had a significantly improved Cobb angle, less levels fused, and more lumbar lordosis, and less blood transfusions when compared to posterior instrumentation. In addition, patients undergoing anterior instrumentation had a significantly lower rate of revision surgery compared to those with posterior instrumentation. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00333-4 P87. Patterns and trends of opioid use among individuals with back pain in the U.S. Xuemei Luo, PhD1, Ricardo Pietrobon, MD1, Lloyd Hey, MD1; 1Duke University Medical Center, Durham, NC, USA HYPOTHESIS: There is variation on opioid use among individuals with back pain who had different demographic, socioeconomic characteristics and from different geographic regions. From 1996 to 1999, overall use of opioid among individuals with back pain was not dramatically changed but the use of specific opioid may increase or decrease. METHODS: This study used the data from 1996 to 1999 Medical Expenditure Panel Survey, a national survey database on health care utilization and expenditures. Patterns of opioid use were examined by stratifying individuals with back pain by demographic, socioeconomic characteristics and geographical regions, and comparing the rate of opioid use during each of the four years (1996–1999) among the different strata. Trends of opioid use were assessed by comparing the rate of overall and specific opioid use across the four-year span. RESULTS: Several consistent or evolving patterns on opioid use were observed among individuals with back pain from 1996 to 1999. For each of the four years, there was no difference in opioid use according to sex and
ethnicity but the use of opioid was significantly higher among individuals who were publicly insured, had low or below low income and had education at or below 12th grade than their respective counterparts. Significant variations in opioid use according to age or region were observed in early years and became non-significant in later years. Rates of overall opioid use slightly increased from 1996 to 1999. Among individual opioid categories, the use of oxycodone or hydrocodone increased whereas the use of propoxyphene decreased across the 4-year span. DISCUSSION: To our knowledge, this is the first study to examine at the national level the patterns and trends of opioid use among individuals with back pain in the US. CONCLUSIONS: Our study indicated several consistent or evolving patterns and some interesting trends on opioid use among individuals with back pain in the US. Most notably, the overall use of opioid was significantly higher among individuals who were publicly insured, had low or below low income and had education at or below 12th grade than their respective counterparts. The use of two specific opioid, oxycodone and hydrocodone, demonstrated increasing trends from 1996 to 1999. Because Opioid can have serious side effects, has the potential for addition and there is a lack of scientifically sound studies about its efficacy for back pain, the significantly higher use of opioid among individuals who were publicly insured, had low or below low income and had education at or below 12th grade raises serious concerns about drug safety among these people. More studies are needed to understand why these individuals were more likely to use opioid and what outcomes are associated with this higher usage. Future studies are also needed to examine the efficacy and safety of specific opioid, especially those that demonstrated increasing trends of use during recent years, among individuals with back pain. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00334-6
P92. Minimum one year results of the PRODISC II lumbar total disc replacement Patrick Tropiano, MD1, Russel Huang, MD2, Federico Girardi, MD2, Thierry Marnay, MD3; 1Hoˆpital CHU Nord, Marseille, France; 2 Hospital for Special Surgery, New York, NY, USA; 3Clinique du Parc, Castelnau Le Lez, France HYPOTHESIS: We hypothesized that lumbar total disc replacement (TDR) with the PRODISC II prosthesis would result in clinically and statistically significant improvement in low back pain, radicular leg pain, and disability in patients with symptomatic degenerative disc disease who had failed nonsurgical treatment. METHODS: We prospectively assessed 53 patients who had single or multilevel lumbar disc replacement with the PRODISC II TDR at mean 1.4-year (range 1–2) follow-up. There were 18 men and 35 women with a mean age of 45 years (range 28–67). Preoperative diagnoses included disc degeneration (33 patients) and failed spine surgery (20 patients), and all patients had at least 6 months of severe back pain and had failed nonsurgical treatment. Exclusion criteria included facet arthrosis, central or lateral recess stenosis, osteoporosis, deficiency of posterior elements (laminae or facets), and sagittal or coronal plane deformity. Patient evaluation consisted of pre- and postoperative back and leg pain VAS scores, Oswestry disability questionnaires, and radiographs. Clinical evaluation and questionnaire administration was performed by individuals not directly involved in patient selection, surgery, or postoperative care. RESULTS: There were clinically and statistically significant improvements in back and leg pain VAS and Oswestry disability scores that were maintained at final follow-up. Mean lumbar VAS decreased from 7.4 to 1.3 at final follow-up. Mean radicular VAS decreased from 6.7 to 1.9. Oswestry disability scores improved from 56 to 14. VAS and Oswestry improvements were statistically significant (p⬍0.05). The clinical results of patients with single and multilevel surgery were equivalent. Satisfactory results were achieved in 90% of patients who had previous lumbar surgery. Mean
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
141S
flexion-extension range of motion of implants was 8 degrees (range 2–12) at L5-S1 and 10 degrees (range 8–18) at L4-L5. Complications occurred in 9% of patients and included vertebral body fracture, transient radicular pain, implant malposition, and transient retrograde ejaculation. Three patients (6%) required reoperation to address complications. No mechanical failure of the implants or loosening was observed. DISCUSSION: Total disc replacement has the potential to replace fusion as the gold standard surgical treatment for degenerative disc disease. Potential advantages of TDR over fusion include avoidance of pseudarthosis, postoperative orthoses, and junctional degeneration. There are no published studies with minimum 1-year follow-up of the PRODISC II prosthesis. Longerterm follow-up of the SB Charite´ prosthesis has been reported, but there are significant biomechanical differences between the two implants, especially with regard to kinematics and constraint. Randomized trials comparing fusion to disc replacement and comparing different TDR implants with long follow-up periods are required to determine to relative merits of the various procedures and implants. CONCLUSIONS: In properly selected patients, lumbar TDR with the PRODISC II has excellent clinical and radiographic results at mean 1.4year follow-up. Patients with single or multilevel degenerative disc disease are candidates for this procedure. Implant malposition and intra-operative fracture resulted in a 6% reoperation rate. DISCLOSURES: Device or drug: PRODISC II lumbar disc replacement. Status: investigational. CONFLICT OF INTEREST: Federico Girardi, MD, Thierry Marnay, MD, stockholders: Spine Solutions, Inc. Thierry Marnay, MD, grant research support: for research staff; board member: Spine Solutions, Inc.
good results, 8.5% reported fair results, and 1.1% reported poor results. In group 2, 28% of the patients reported excellent results, 62% reported good results, and 10% reported fair results. All nonunions reported good outcomes. Postoperative respiratory distress developed in one patient and dysphagia developed in another both from group 1. No other complications were noted. The presence or absence of direct uncovertebral joint decompression and clinical outcome was not statistically significant (p⬎0.05). The use of graft-type, operative level, presence of smoking, and work-related injury in relation to clinical outcome was not found to be significant. DISCUSSION: Satisfactory results were obtained in 90.5% and 90.0% of patients for groups 1 and 2, respectively. Good to excellent results in relieving neck pain and radicular symptoms were obtained in 90% of patients who underwent direct uncovertebral joint decompression and in patients with indirect decompression by distraction and leaving the uncovertebral joint intact. CONCLUSIONS: Indirect foraminal decompression through distraction remains somewhat controversial during ACDF, however sacrificing the uncovertebral joint can increase operative time and potentially increase complication rates. This study demonstrates that ACDF with or without direct uncovertebral joint decompression can provide good clinical results for neck pain with cervical radiculopathy. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts.
doi: 10.1016/S1529-9430(03)00335-8
P102. Multidirectional stability of a dynamic stabilization system over graf ligamentoplasty: the effect of various posterior stabilizing implants Osamu Shirado, MD1, Yoshihiro Hojo, MD1, Akio Minami, MD1; 1 Hokkaido University, Sapporo, Japan
P97. Clinical outcome in patients undergoing anterior cervical discectomy and fusion with or without direct uncovertebral joint decompression Francis Shen, MD1, Dino Samartzis1, Edward Goldberg1, Howard An1; 1Rush-Presbyterian-St. Luke’s Medical Center/Rush University, Chicago, IL, USA HYPOTHESIS: Anterior cervical discectomy and fusion (ACDF) is an established procedure for the treatment of cervical disc disease. Studies demonstrate that in patients with radiculopathy secondary to impingement from uncovertebral joint osteophytes, direct decompression of the offending lesion provides excellent clinical outcome. However known complications include vertebral artery injury, dural tears, nerve root injury, and loss of biomechanical stability. Other studies suggest that disc space distraction may also play an important role by indirectly decompressing neural elements. We hypothesis that patients the undergo ACDF without direct uncovertebral joint decompression will have similar clinical outcomes to those that undergo ACDF with direct decompression. METHODS: Clinical outcome of 144 consecutive patients (mean 46 years, range 27–83) that underwent ACDF with constrained plate fixation were reviewed at a single institution. Patients with radiculopathy due to herniated disc, spondylosis, or a combination of both refractory to conservative treatment underwent surgery utilizing a standard Smith-Robinson left-sided approach. Ninety-four patients that received direct uncovertebral joint decompression (group 1) were compared to 50 patients without direct decompression but indirect decompression by disc space distraction (group 2). In group 1, 54 one-level and 40 two-level ACDFs were performed. In group 2, 18 and 32 were one-level and two-level ACDFs respectively. The presence of smoking and work-related injuries involved 32.9% and 43.6% of group 1 and 26% and 32% of group 2, respectively. Autologous iliac crest grafts was used in 65 patients, while 79 patients received allograft. Blinded analyses of plain radiographs were conducted (mean, 9.2 months). Clinical outcomes were reported as excellent, good, fair or poor (mean, 15 months) based on Odom’s criteria. RESULTS: Fusion occurred in 95.7% of group 1 and 100% of group 2. In group 1, 27.7% of the patients reported excellent results, 62.8% reported
doi: 10.1016/S1529-9430(03)00336-X
HYPOTHESIS: An expected advantage of Graf ligamentoplasty over spinal fusion is the decrease risk of adjacent-segment morbidity by stabilizing unstable segments without requiring rigid spinal arthrodesis. However, it remains controversial whether the Graf system can be rigid enough to stabilize an unstable spine. Thus, refinement of the Graf system has recently been highlighted in the literature. The purpose of this study was to biomechanically evaluate multidirectional stability of the dynamic stabilization systems using various posterior stabilizing implants. We hypothesized that this system could provide the multidirectional stability for unstable lumbar spines. METHODS: Twelve fresh calf lumbar spine specimens (L2-sacrum) were subjected to compression (100 N), flexion and extension (5 N-m), lateral bending (5 N-m), and rotation (10 N-m). The load-displacement curves were simultaneously measured. Testing of the intact spine preceded testing of the L4-5 destabilized spine (performed by bilateral medial facetectomies), and in each of the following stabilizing treatment groups: Graf ligamentoplasty, Graf with posterior titanium springs between the pedicle screws, Graf with an interspinous coiled artificial ligament, Graf with an interspinous ceramic spacer, and a rigid pedicle screw system. Extensometers were applied to measure the strain in the stabilized (L4-5) and adjacent segments (L3-4). Statistical analysis was carried out using one-way ANOVA. RESULTS: In the flexion and compression, the strain at L4-5 was not significantly different among all the stabilized constructs except the rigid pedicle screw system. During extension, lateral bending, and rotation, Graf ligamentoplasty enhanced with the various posterior implants were more stable than Graf ligamentoplasty alone (p⬍0.05). The construct enhanced with the ceramic spacer was the most stable of the treatment groups (p⬍.05). The posteriorly enhanced systems were more flexible than the rigid pedicle screw system. Furthermore, the strain at the adjacent segment (L3-4) in the posteriorly enhanced constructs was significantly lower than using the rigid pedicle screw system. DISCUSSION: The current study demonstrates that the Graf ligamentoplasty can provide a multi-directional dynamic stabilization for the