Biomedical subjects

G Bryan Cornwall

Publications and source records attributed to G Bryan Cornwall.

16 recordsLinked to original sources

PubMed2006

Evaluation of a bioresorbable polylactide sheet for the reduction of pelvic soft tissue attachments in a porcine animal model.

In an adult porcine model, the effectiveness of a bioresorbable film to minimize soft tissue attachment to the pelvic viscera was evaluated at 4-week and 12-week endpoints. Following a transperitoneal laparotomy through a midline incision, the bladder and uterus were abraded in all animals to promote soft tissue attachment to the viscera. Control animals received no further treatment. The experimental group animals were treated with bioresorbable polylactide (PLa) sheets, 0.02 mm thick, one between the bladder and the abdominal wall, and a second sheet between the bladder and the uterus. Quantitative assessment of the severity and location of soft tissue attachments, and qualitative histologic assessment were performed at 4 and 12 weeks post-operatively. Statistically significant differences in the quantitative soft tissue attachment scores were observed in comparing the PLa film treated animals versus the control animals, at both the 4-week and 12-week time points. In the control animals, the formation of numerous thick fibrous bands was observed at both time points. Histology revealed no adverse reaction to the bioresorbable PLa barrier film. The bioresorbable PLa sheet provided an effective barrier between adjacent anatomical structures and minimized soft tissue attachments to the device when in contact with the viscera as compared to the control groups. Surgical dissection planes between the abdominal wall and adjacent soft tissues were maintained with the use of the PLa sheet at both time points.

Absorbable Implants↗

PubMed2004

Use of polylactide resorbable film as a barrier to postoperative peridural adhesion in an ovine dorsal laminectomy model.

OBJECT: The purpose of this study was to evaluate the performance of a resorbable polylactide film in the sheep posterior spine in the presence of a combined laminectomy and durotomy defect. METHODS: A resorbable polylactide film was used to cover the combined defects in the eight sheep used in this study. Two surgical levels were performed in each animal, with randomly assigned control and treated sites. Each surgical level consisted of a full laminectomy followed by a needle-induced durotomy. The treated levels received a resorbable polylactide film cut to size and tucked in under the laminar defect. At 8 to 10 weeks postoperatively, results of myelography and visual dye infiltration showed complete healing of the durotomies for all sites. In addition, evaluation of gross dissection based on volume and tenacity scores as well as histological findings indicates decreased posterior dural adhesions for sites treated with resorbable polylactide film. CONCLUSIONS: The results of this investigation support previous studies in which the use of a resorbable polylactide film was found to be effective in reducing posterior dural adhesions in the spine with no apparent safety issues related to impaired dural healing.

Absorbable Implants↗

PubMed2004

In vivo evaluation of bioresorbable polylactide implants for cervical graft containment in an ovine spinal fusion model.

OBJECT: An in vivo study was conducted in an ovine model to investigate the biomechanical changes after the animals underwent single-level anterior cervical discectomy followed by fusion in which autologous tricortical graft was used and implantation of cervical plates for which bioresorbable polymer screws and plates were used. The specific aims of the study were to evaluate whether implant failure or screw backout would occur over time and to measure the change in stiffness at the treated level at various postoperative time periods (3, 6, and 12 months). METHODS: A total of 58 x-ray films were evaluated over the 12-month survival period. No screw breakage or displacement was observed in any animal during the temporal radiographic analysis. Radiographically confirmed fusion appeared to be complete at all time periods longer than 6 months. The biomechanical testing demonstrated dramatic reductions in range of motion at the fusion level in the animals allowed to survive for 6 and 12 months, indicating complete fusion after 6 months. CONCLUSIONS: The bioresorbable polymer cervical graft containment system appears to provide a safe and effective alternative for cervical fusion, and warrants further clinical evaluation for its use in single-level anterior cervical discectomy and fusion without postoperative orthosis.

Absorbable Implants↗

PubMed2004

MacroPore resorbable devices in craniofacial surgery.

Resorbable polymer implants have become a compelling option in the treatment of acquired and congenital craniofacial deformities. The resorbable polylactide (PLa) and polyglycolide (PGa) polymers in particular have demonstrated excellent safety profile sin multiple in vitro, animal, and clinical studies and are currently being used in a wide variety of craniofacial applications. In this article, the authors discuss the biomaterial properties of PLa and PGa resorbable implants and provide an overview of the use of these polymers in craniofacial surgery. They conclude by relating their experience with an ongoing clinical series using MacroPore PLDLa and FRP implants for various applications,including Le Fort osteotomies, midface/monobloc internal distraction, and craniosynostosis reconstruction.

Absorbable Implants↗

PubMed2002

Use of polylactide resorbable film as an adhesion barrier.

OBJECT: The present investigation evaluates two thicknesses of a resorbable polylactic acid (PLA) barrier film as an adhesion barrier to posterior spinal scar formation. METHODS: A readily contourable, thin film was placed directly over the dura. The thick film was placed above the lamina defect to act as a physical barrier inhibiting the prolapse of soft tissue into the epidural space. Through a combination of gross dissection with and without scar scores, quantitative analysis of collagen adjacent to the scar site, and histological evaluation, the resorbable adhesion barrier membranes were found to be effective treatment for reduction of posterior adhesions. CONCLUSIONS: The gross dissection demonstrated that both thicknesses of resorbable PLA barrier films created a controlled dissection plane, facilitated access to the epidural space, and provided a reduction in the tissue adherent to the dura.

Absorbable Implants↗

PubMed2002

Evaluation of 70/30 poly (L-lactide-co-D,L-lactide) for use as a resorbable interbody fusion cage.

OBJECT: Titanium lumbar interbody spinal fusion devices are reported to be 90% effective in cases requiring single-level lumbar interbody arthrodesis, although radiographic determination of fusion has been debated. METHODS: Using blinded radiographic, biomechanical, histological, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) interbody fusion device packed with autograft or recombinant human bone morphogenetic protein-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologically confirmed fusion was demonstrated at 3 months to 24 months postimplantation. Device degradation was associated with a mild to moderate chronic inflammatory response at all postoperative sacrifice times. CONCLUSIONS: Use of this material in interbody fusion may be a viable alternative to metals.

Absorbable Implants↗

PubMed2002

Feasibility of a resorbable anterior cervical graft containment plate.

In this article the authors review the history of anterior cervical plating for one- and two-level discectomy for degenerative disease and provide background justification for the design and testing of a cervical plate composed of a resorbable material. The design of the plate is discussed with special reference to modifications of its design and tools compared with metallic plates that are necessary because of the different mechanical properties of the less rigid material. The cadaveric and animal in vivo testing methodologies are described, and a novel testing method for reliably quantifying graft containment is also described. Data from a representative sample are presented. Advantages and disadvantages of resorbable plating are discussed.

Absorbable Implants↗

PubMed2002

Bioabsorbable anterior lumbar plate fixation in conjunction with cage-assisted anterior interbody fusion.

OBJECT: An in vitro biomechanical study was conducted to determine the effects of anterior stabilization on cage-assisted lumbar interbody fusion biomechanics in a multilevel human cadaveric lumbar spine model. METHODS: Three spine conditions were compared: harvested, bilateral multilevel cages (CAGES), and CAGES with bioabsorbable anterior plates (CBAP), tested under flexion-extension, lateral bending, and axial rotation. Measurements included vertebral motion, applied load, and bending/rotational moments. Application of anterior fixation decreased local motion and increased stiffness of the instrumented levels. Clinically, this spinal stability may serve to promote fusion. CONCLUSIONS: Coupled with the bioabsorbability of the plating material, the bioabsorbable anterior lumbar plating system is considered biomechanically advantageous.

Absorbable Implants↗

PubMed2002

Use of a resorbable sheet in iliac crest reconstruction in a sheep model.

OBJECT: Iliac crest bone graft harvesting can result in major complications, the rates of which range from approximately 6 to 8%. The objective of this study was to evaluate the postoperative regeneration of iliac crest donor defects in an animal model after harvesting a full-thickness tricortical graft. METHODS: In skeletally mature sheep, a tricortical iliac crest graft was harvested. The graft sites were allowed to heal unprotected or protected with the resorbable polylactic acid sheet material, MacroPore OS Protective Sheeting. After 6 months of healing, the sites were assessed by examination of undecalcified histological sections. Histomorphometric measurements of the original defect area, the area of new bone within the defect site, and the percentage of defect filled with new bone were quantified for both control and protected groups. In all histological sections, new bone growth within the defect sites appeared normal, with no observed excessive inflammatory cells. The developing bone tissue appeared to be remodeling normally. For the unprotected sites, the area of new bone averaged 16.3 mm2 (+/- 7.2 mm2), and the percentage of the defect area filled with bone averaged 10.7% (+/- 6.5%). In the protected sites, the area of new bone averaged 64.8 mm2 (+/- 11.6 mm2) and the percentage of the defect area filled with bone averaged 25.9% (+/- 1.6%). Both differences in area of new bone growth and percentage of defect area filled were statistically significant. Literature review has indicated that regeneration of donor site defects is desirable. CONCLUSIONS: Based on the results of the present study, MacroPore resorbable Protective Sheeting can improve bone regeneration significantly within the donor site following tricortical iliac crest graft harvesting.

Absorbable Implants↗

PubMed2002

Resorbable posterolateral graft containment in a rabbit spinal fusion model.

OBJECT: The authors studied the effect of a resorbable graft containment device in a rabbit posterolateral lumbar spinal fusion model. METHODS: Twenty rabbits were divided into four groups: autologous bone graft (ABG), ABG with the MacroPore containment device (ABG + MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM + MP). Fusion mass was assessed at 6 weeks with high-resolution radiography and volumetric computerized tomography. The graft containment device was associated with alteration of the fusion mass structure and significant enhancement of fusion mass volume (ABG versus ABG + MP, p = 0.027; DBM versus DBM + MP, p = 0.043). CONCLUSIONS: A bioabsorbable protective graft containment device successfully enhanced posterolateral spinal fusion mass volume.

Absorbable Implants↗

PubMed2002

Use of polylactide resorbable film as an adhesion barrier.

The present investigation evaluates two thicknesses of a resorbable polylactide barrier film as an adhesion barrier to posterior spine scar formation. A readily contourable, thin film was placed directly over the dura. The thick film was placed above the lamina defect to act as a physical barrier inhibiting the prolapse of soft tissue into the epidural space. Through a combination of gross dissection with and without scar scores, quantitative analysis of collagen adjacent to the scar site, and histologic evaluation, the resorbable adhesion barrier membranes were found to be effective treatment for reduction of posterior adhesions. The gross dissection demonstrated that both thicknesses of resorbable polymer barrier films created a controlled dissection plane, facilitated access to the epidural space, and provided a reduction in the tissue adhered to the dura.

Absorbable Implants↗

PubMed2002

Evaluation of 70/30 D,L-PLa for use as a resorbable interbody fusion cage.

Titanium lumbar interbody spinal fusion devices are reported to be 90% effective for single-level lumbar interbody fusion, although radiographic determination of fusion has been debated. Using blinded radiographic, biomechanic, histologic, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) (70/30 D,L-PLa) interbody fusion device packed with autograft or rhBMP-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologic fusion was demonstrated from 3 months to 24 months. Device degradation was associated with a mild to moderate chronic inflammatory response at all postoperative sacrifice times.

Absorbable Implants↗

PubMed2002

Feasibility of a resorbable anterior cervical graft containment plate.

In this article we review the background of anterior cervical plating for one- and two-level diskectomy for degenerative disease and provide background justification for the design and testing of a cervical plate composed of a resorbable material. The design of the plate is discussed with special reference to modifications of implant design and implant tools compared with metallic plates that are necessary because of the different mechanical properties of the less rigid material. Our cadaveric and animal in vivo testing methodologies are described and a novel testing method for reliably quantifying graft containment is also described. Data from a representative sample are presented. Advantages and disadvantages of resorbable plating are discussed.

Absorbable Implants↗

PubMed2002

Bioabsorbable anterior lumbar plate fixation in conjunction with anterior interbody fusion cages.

An in vitro biomechanical study was conducted to determine the effects of anterior stabilization on lumbar interbody cage fusion biomechanics in a multilevel human cadaveric lumbar model. Three spine conditions were compared: harvested, bilateral multilevel cages (CAGES), and CAGES with bioabsorbable anterior plates (CBAP), tested under flexion/extension, lateral bending, and axial rotation. Measurements included vertebral motion, applied load, and bending/rotational moments. Application of anterior fixation decreased local motion and increased stiffness of the instrumented levels. Clinically, this spinal stability may serve to promote fusion. Coupled with the bioabsorbability of the plating material, the bioabsorbable anterior lumbar plating system is considered biomechanically advantageous.

Absorbable Implants↗

PubMed2002

Use of a resorbable sheet in iliac crest reconstruction in a sheep model.

Iliac crest bone graft harvesting can result in major complications that occur at rates of approximately 6%-8%. The objective of this study was to evaluate the postoperative regeneration of iliac crest donor defects in an animal model after harvesting a full-thickness tricortical graft. In skeletally mature sheep, a tricortical iliac crest graft was harvested. The graft sites were allowed to heal nonprotected or protected with the resorbable polylactic acid sheet material, MacroPore OS Protective Sheeting, (MacroPore Biosurgery, San Diego, Calif). After 6 months of healing, the sites were assessed by examination of undecalcified histologic sections. Histomorphometric measurements of the original defect area, the area of new bone within the defect site, and the percentage of defect filled with new bone were quantified for both control and protected groups. In all histologic sections, new bone growth within the defect sites appeared normal, with no excessive inflammatory cells observed. The developing bone tissue appeared to be remodeling normally. For the nonprotected sites, the area of new bone averaged 16.3 mm2 (+/-7.2 mm2), and the percentage of the defect area filled with bone averaged 10.7% (+/-6.5%). In the protected sites, the area of new bone averaged 64.8 mm2 (+/-11.6 mm2) and the percentage of the defect area filled with bone averaged 25.9% (+/-1.6%). Both differences in area of new bone growth and percentage of defect area filled were statistically significant. Literature review has indicated that regeneration of donor site defects is desirable. Based upon the results of the present study, MacroPore resorbable protective sheeting can improve bone regeneration significantly within the donor site following tricortical iliac crest graft harvesting.

Absorbable Implants↗

PubMed2002

Resorbable posterolateral graft containment in a rabbit spinal fusion model.

The effect of a resorbable graft containment device was evaluated in a rabbit posterolateral lumbar spinal fusion model. Twenty rabbits were divided into four groups: autogenous bone graft (ABG), ABG with the MacroPore containment device (MacroPore Biosurgery Inc, San Diego, Calif) (ABG+MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM+MP). Fusion mass was assessed at 6 weeks with high resolution radiographs and volumetric computed tomography (CT). The graft containment device was associated with alteration of the fusion mass structure and significant enhancement of fusion mass volume (ABG versus ABG+MP, P=.027; DBM versus DBM+MP, P=.043). A bioabsorbable, protective graft containment device successfully enhanced posterolateral spinal fusion mass volume.

Absorbable Implants↗