- Email: [email protected]
28. Evaluation of three commercially available synthetic bone grafts in a clinically relevant ovine model of instrumented lumbar posterolateral fusion
S14
Proceedings of the 34th Annual Meeting of the North American Spine Society / The Spine Journal 19 (2019) S1−S58
variables. Pearson’s tests were used to assess correlations. p<0.05 set statistical significance. RESULTS: Ninety patients (95 episodes of care; average age 70.5§10.6 years; male-31, female-59) were included. After operations, average inpatient length of stay was 8.2§2.6 days (4-16 days). Operative details included: posterior levels fused 13.6§3.6 (7-21 levels), posterior column osteotomies (per patient) 7§3.7 (range, 1-15; n=49 patients), forty-two 3COs (PSO-35, VCR-7), and 11 interbody fusions. Average direct costs were $90,738§$24,166 ($36,521−$141,090) for index inpatient stays and $38,808§$14,752 ($8,679−$100,829) for post-discharge acute rehabilitation (Figure 1). Patients spent an average of 11.7§4.0 days (2-28 days) in acute rehabilitation postdischarge. Average direct cost per day in rehabilitation was $3,338 §$2,131 ($506-$4,340). Significant improvements in function (FIM) were observed [admit: 66§14 (15−91) vs discharge: 94§ 14 (54−116); % improvement: 29§14]. CONCLUSIONS: Postdischarge inpatient acute rehabilitation following operations for adult spinal deformity is associated with an average direct cost of $38,808 per case. While rehabilitation resulted in significant functional improvements, it came at a very significant economic expense amounting to $3.7 million, which accounted for 30% of the costs for 95 episodes of care. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2019.05.040
Wednesday, September 25, 2019 7:30 − 8:55 AM Thoracolumbar Surgery I 28. Evaluation of three commercially available synthetic bone grafts in a clinically relevant ovine model of instrumented lumbar posterolateral fusion Lukas A. van Dijk, MSc; University Medical Centre Utrecht, Utrecht, Netherlands BACKGROUND CONTEXT: Synthetic bone grafts are important tools for spinal surgeons who wish to avoid the invasive harvesting of autologous bone graft for spinal fusions. Various synthetic bone grafts are available on the market, including materials based on bioglass, calcium phosphate or a combination of both. Side-by-side comparisons of synthetic bone grafts in relevant preclinical study models can provide valuable insights that can aid in the selection of treatment options. PURPOSE: The current study compared three commercially available synthetic bone grafts as stand-alone grafts in a clinically relevant ovine model of instrumented posterolateral fusion (PLF). STUDY DESIGN/SETTING: The three different synthetic bone grafts evaluated are: (1) putty formulation of biphasic calcium phosphate with submicron topography that was previously shown to have equivalent performance to autograft in this model (BCP; MagnetOs Putty, Kuros Biosciences BV), (2) putty formulation of 45S5 bioglass (BG; Novabone Putty, Novabone Products LLC), (3) composite of beta-tri-calcium phosphate, 45S5 bioglass and bovine type I collagen (TCP+BG; Vitoss BA2X Foam pack, Orthovita, Inc). Autograft bone (AB) was used as positive control. Twelve weeks after implantation, the treatments were evaluated. OUTCOME MEASURES: Main study end points include fusion assessment by manual palpation, X-ray imaging and micro-CT scans. Range of motion (ROM) of spine levels was assessed in lateral bending (LB) and flexion-extension (FE). Quantification of fusion mass volume was performed using micro-CT. Histology was performed to evaluate bone formation and tissue responses with the different graft materials. METHODS: Following ethical approval, 9 sheep underwent instrumented PLF surgery at L2-3 and L4-5 levels. Autograft was harvested from the Os Ilium and distal femur. After decortication of the transverse processes (TPs), 10 cc of each graft material (AB; n=6, BCP; n=6, BG; n=3, TCP +BG; n=3) was implanted bilaterally in the posterolateral regions, bridging
the inter-transverse process space. After sacrifice, specimens were assessed by manual palpation, X-ray imaging, Micro-CT and ROM testing at 7.5 Nm after removing instrumentation. Subsequently, treated spine levels were processed for histology in polymethylmethacrylate to visualize bone tissue in the fusion mass. RESULTS: Fusion assessment by manual palpation revealed a 6/6 fusion rate for AB and BCP, while for both BG and TCP+BG, a 1/3 fusion rate was determined. Fusion assessment of X-ray and Micro-CT were consistent and determined an either unilateral or bilateral robust bone bridge in 6/6 levels for both AB and BCP, while The BG group exhibited unilateral bridging in 2/3 levels and the TCP+BG group did not include a robust bone bridge in any of the levels. ROM testing revealed equivalent ROMs in LB and FE for AB and BCP, being substantially and significantly lower than those of BG and TCP+BG groups. Fusion mass volume quantification determined fusion mass volumes of 5.7 § 1.6 cm3 for AB, 9.6 § 0.4 cm3 for BCP, 3.0 § 1.1 cm3 for BG and 2.4 § 1.0 cm3 for TCP+BG. Correspondingly, histology revealed significant graft resorption for BG and TCP +BG groups, while abundant bone tissue in the inter-TP space was observed for AB and BCP. A continuous bony bridge in between TPs was frequently observed in the BCP group on histological sections. CONCLUSIONS: Calcium phosphate with submicron topography was the only synthetic bone graft to perform equally well as autograft as a standalone graft in this PLF model. Both bioglass-based bone grafts significantly underperformed as compared to autograft and BCP on every single assessment method. The bioglass-based synthetics were observed to undergo significant resorption and were not able to induce bone formation in the soft tissue region in between the TPs. Calcium phosphate with submicron topography may be the better treatment option than bioglass-based bone grafts as a synthetic bone graft substitute. FDA DEVICE/DRUG STATUS: MagnetOs Granules (Investigational/ Not approved), Novabone Putty (Approved for this indication), Vitoss BA2X (Approved for this indication). https://doi.org/10.1016/j.spinee.2019.05.041
29. Understanding surgeon decision-making and current surgical practice regarding the DSIC scheme and DLS treatment: a CSORN study Audrey Maher; Ottawa, ON, Canada BACKGROUND CONTEXT: Degenerative lumbar spondylolisthesis (DLS) is a spinal pathology involving the slip of one or more lumbar spinal vertebrae. It is most common in women and African-Americans above the age of 50, and usually involves the anterior slip of the fourth lumbar vertebra of up to 30% of its vertebral body width due to the more sagittally-oriented facet joints, and therefore, high force concentration at that level. Despite its worldwide prevalence of about 6%, the classification and treatment of DLS is not standardized. In 2015, Simmonds et al published the largest to-date systematic review of best available evidence and proposed a degenerative spondylolisthesis instability classification (DSIC) scheme. This classification scheme proposes that the stability of the patient’s pathology be determined by a surgeon based on quantitative and qualitative clinical and radiographic parameters. PURPOSE: This study aims to determine whether surgeons are following DSIC scheme treatment recommendations. It also aims to determine which radiographic and/ or clinical parameters and/ or surgeon characteristics are most influencing classification and treatment decisions. The goal of this study is to shed light on current surgeon treatment decisions and to better understand the factors most taken into account. In order for the treatment of DLS to become standardized, and therefore uniform and cost effective, we must first understand how current treatment decisions are made. STUDY DESIGN/SETTING: This study used data from CSORN collected by surgeons across Canada between 2015 and 2018. Statistical analysis was used to determine which factors most influenced the classification and treatment decision of the surgeons. PATIENT SAMPLE: A total of 224 patients.
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.
Proceedings of the 34th Annual Meeting of the North American Spine Society / The Spine Journal 19 (2019) S1−S58
variables. Pearson’s tests were used to assess correlations. p<0.05 set statistical significance. RESULTS: Ninety patients (95 episodes of care; average age 70.5§10.6 years; male-31, female-59) were included. After operations, average inpatient length of stay was 8.2§2.6 days (4-16 days). Operative details included: posterior levels fused 13.6§3.6 (7-21 levels), posterior column osteotomies (per patient) 7§3.7 (range, 1-15; n=49 patients), forty-two 3COs (PSO-35, VCR-7), and 11 interbody fusions. Average direct costs were $90,738§$24,166 ($36,521−$141,090) for index inpatient stays and $38,808§$14,752 ($8,679−$100,829) for post-discharge acute rehabilitation (Figure 1). Patients spent an average of 11.7§4.0 days (2-28 days) in acute rehabilitation postdischarge. Average direct cost per day in rehabilitation was $3,338 §$2,131 ($506-$4,340). Significant improvements in function (FIM) were observed [admit: 66§14 (15−91) vs discharge: 94§ 14 (54−116); % improvement: 29§14]. CONCLUSIONS: Postdischarge inpatient acute rehabilitation following operations for adult spinal deformity is associated with an average direct cost of $38,808 per case. While rehabilitation resulted in significant functional improvements, it came at a very significant economic expense amounting to $3.7 million, which accounted for 30% of the costs for 95 episodes of care. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2019.05.040
Wednesday, September 25, 2019 7:30 − 8:55 AM Thoracolumbar Surgery I 28. Evaluation of three commercially available synthetic bone grafts in a clinically relevant ovine model of instrumented lumbar posterolateral fusion Lukas A. van Dijk, MSc; University Medical Centre Utrecht, Utrecht, Netherlands BACKGROUND CONTEXT: Synthetic bone grafts are important tools for spinal surgeons who wish to avoid the invasive harvesting of autologous bone graft for spinal fusions. Various synthetic bone grafts are available on the market, including materials based on bioglass, calcium phosphate or a combination of both. Side-by-side comparisons of synthetic bone grafts in relevant preclinical study models can provide valuable insights that can aid in the selection of treatment options. PURPOSE: The current study compared three commercially available synthetic bone grafts as stand-alone grafts in a clinically relevant ovine model of instrumented posterolateral fusion (PLF). STUDY DESIGN/SETTING: The three different synthetic bone grafts evaluated are: (1) putty formulation of biphasic calcium phosphate with submicron topography that was previously shown to have equivalent performance to autograft in this model (BCP; MagnetOs Putty, Kuros Biosciences BV), (2) putty formulation of 45S5 bioglass (BG; Novabone Putty, Novabone Products LLC), (3) composite of beta-tri-calcium phosphate, 45S5 bioglass and bovine type I collagen (TCP+BG; Vitoss BA2X Foam pack, Orthovita, Inc). Autograft bone (AB) was used as positive control. Twelve weeks after implantation, the treatments were evaluated. OUTCOME MEASURES: Main study end points include fusion assessment by manual palpation, X-ray imaging and micro-CT scans. Range of motion (ROM) of spine levels was assessed in lateral bending (LB) and flexion-extension (FE). Quantification of fusion mass volume was performed using micro-CT. Histology was performed to evaluate bone formation and tissue responses with the different graft materials. METHODS: Following ethical approval, 9 sheep underwent instrumented PLF surgery at L2-3 and L4-5 levels. Autograft was harvested from the Os Ilium and distal femur. After decortication of the transverse processes (TPs), 10 cc of each graft material (AB; n=6, BCP; n=6, BG; n=3, TCP +BG; n=3) was implanted bilaterally in the posterolateral regions, bridging
the inter-transverse process space. After sacrifice, specimens were assessed by manual palpation, X-ray imaging, Micro-CT and ROM testing at 7.5 Nm after removing instrumentation. Subsequently, treated spine levels were processed for histology in polymethylmethacrylate to visualize bone tissue in the fusion mass. RESULTS: Fusion assessment by manual palpation revealed a 6/6 fusion rate for AB and BCP, while for both BG and TCP+BG, a 1/3 fusion rate was determined. Fusion assessment of X-ray and Micro-CT were consistent and determined an either unilateral or bilateral robust bone bridge in 6/6 levels for both AB and BCP, while The BG group exhibited unilateral bridging in 2/3 levels and the TCP+BG group did not include a robust bone bridge in any of the levels. ROM testing revealed equivalent ROMs in LB and FE for AB and BCP, being substantially and significantly lower than those of BG and TCP+BG groups. Fusion mass volume quantification determined fusion mass volumes of 5.7 § 1.6 cm3 for AB, 9.6 § 0.4 cm3 for BCP, 3.0 § 1.1 cm3 for BG and 2.4 § 1.0 cm3 for TCP+BG. Correspondingly, histology revealed significant graft resorption for BG and TCP +BG groups, while abundant bone tissue in the inter-TP space was observed for AB and BCP. A continuous bony bridge in between TPs was frequently observed in the BCP group on histological sections. CONCLUSIONS: Calcium phosphate with submicron topography was the only synthetic bone graft to perform equally well as autograft as a standalone graft in this PLF model. Both bioglass-based bone grafts significantly underperformed as compared to autograft and BCP on every single assessment method. The bioglass-based synthetics were observed to undergo significant resorption and were not able to induce bone formation in the soft tissue region in between the TPs. Calcium phosphate with submicron topography may be the better treatment option than bioglass-based bone grafts as a synthetic bone graft substitute. FDA DEVICE/DRUG STATUS: MagnetOs Granules (Investigational/ Not approved), Novabone Putty (Approved for this indication), Vitoss BA2X (Approved for this indication). https://doi.org/10.1016/j.spinee.2019.05.041
29. Understanding surgeon decision-making and current surgical practice regarding the DSIC scheme and DLS treatment: a CSORN study Audrey Maher; Ottawa, ON, Canada BACKGROUND CONTEXT: Degenerative lumbar spondylolisthesis (DLS) is a spinal pathology involving the slip of one or more lumbar spinal vertebrae. It is most common in women and African-Americans above the age of 50, and usually involves the anterior slip of the fourth lumbar vertebra of up to 30% of its vertebral body width due to the more sagittally-oriented facet joints, and therefore, high force concentration at that level. Despite its worldwide prevalence of about 6%, the classification and treatment of DLS is not standardized. In 2015, Simmonds et al published the largest to-date systematic review of best available evidence and proposed a degenerative spondylolisthesis instability classification (DSIC) scheme. This classification scheme proposes that the stability of the patient’s pathology be determined by a surgeon based on quantitative and qualitative clinical and radiographic parameters. PURPOSE: This study aims to determine whether surgeons are following DSIC scheme treatment recommendations. It also aims to determine which radiographic and/ or clinical parameters and/ or surgeon characteristics are most influencing classification and treatment decisions. The goal of this study is to shed light on current surgeon treatment decisions and to better understand the factors most taken into account. In order for the treatment of DLS to become standardized, and therefore uniform and cost effective, we must first understand how current treatment decisions are made. STUDY DESIGN/SETTING: This study used data from CSORN collected by surgeons across Canada between 2015 and 2018. Statistical analysis was used to determine which factors most influenced the classification and treatment decision of the surgeons. PATIENT SAMPLE: A total of 224 patients.
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.