Papers by Author: Guy Daculsi

Abstract: Tympanoplasty is the reference for cholesteatoma treatment in ear, nose, and throat (ENT surgery), with the realization of a closing technique, which preserves the external auditory canal. An insufficient pneumatisation is an element favoring the occurrence and recurrence of cholesteatoma. In a prospective clinical pilot study, we have realized the reconstruction of the mastoid cortical bone by a Micro Macroporous Biphasic Calcium Phosphate bioceramics disks (MBCPTM Biomatlante France) using the closed technique, in order to maintain or increase the mastoid pneumatisation. Eleven patients were used for this study, and some of them have a sample collection for histomorphometry and histopathological analysis. Bone regeneration at the expense of the bioceramic was observed. The size and shape of the disk was not preserved due to the large resorption and bone ingrowth at the expense of the implant. However 6 patients presented cholesteatoma recurrence. The MBCPTM disks are able to reconstruct the mastoid cortical and maintain the mastoid pneumatisation contrarily to the technique of filling the mastoid cavity. However, the high rate of cholesteatoma recurrence observed in our study, confirmed the interest to fill mastoid that suppress airspace posterior cavities.

Abstract: Bioceramics draw attention in bone tissue engineering field since their biomimetic properties regarding bone attribute. In this context, a concept of smart bioceramics granules made of Hydroxyapatite have been set up, enhancing surface area available to body fluids containing proteins and cell adhesion for bone forming respectively thanks to microporosities and macropore concavities. New “hollow shell” granules were developed and assessed by physico-chemical characterizations, in-vitro experiments and in-vivo implantation in comparison with classical round granules. This new original galenic formulation showed promising potential in cell carrying and osteoconduction matter.

Abstract: The present study focuses on the physico-chemical and structural properties of composite scaffolds composed of biopolymer matrices (collagen or polysaccharide) loaded with calcium phosphate granules. A systematic three-dimensional analysis method was used to quantitatively characterize a series of plugs, strips and putties in terms of percentage of inorganic filler particles, size of the loaded granules, and spatial homogeneity of the calcium phosphate granules distribution. It appears clearly that each biomaterial currently available on the market offers specific properties. As a consequence, surgeons have to choose the medical device that best suits their needs depending on the clinical constraints but also should be aware of the mineral properties which remains key to bone reconstruction.

Abstract: Solid-state transformation of CDA at high temperature has been investigated using TEM microscopy and diffraction from sintered biphasic calcium phosphate (hydroxyapatite-HA, and beta-tricalcium phosphate-TCP). Microcrystals, between 200nm and 800nm approximately, separated by grain boundaries were found to be either HA-HA or TCP-TCP, but not HA-TCP, suggesting that heteroepitaxial growth is very unlikely between these two orthophosphates. TEM-correlated EDX elemental analysis also demonstrated a higher ionic substitution (Na, Mg) of TCP phase.

Abstract: The main goal of this study was to succeed in the relevant association of well-known osteoconductive biphasic calcium phosphate (BCP) made of Hydroxyapatite (20% HA) and β-Tricalcium Phosphate (80% β-TCP) crystallographic phases and resorbable poly (L-lactide-co-D,L-lactide)(PLDLLA) 3D matrices synthesized by electrospinning. Two types of mineral particles were obtained, BCP new hollow granules, and classical BCP particles. It appeared that hollow shells/PLDLLA composite 3D matrices allowed higher cell adhesion in vitro, thanks to internal concavities and are promising scaffolds in terms of cell carrying.

Abstract: The objective of this study deals with preclinical and clinical cases of absorbable composite interference screws of next generation in osteoarticular surgery. These implants are made of resorbable polymers PLA either amorphous or semi-cristalline, associated with granules of microporous biphasic calcium phosphate ceramic. A preclinical study was performed on goats in femoral and tibial epiphysis during 4 and 6 months. Histological and histomorphometric results were obtained by micro CT, light and scanning electron microscopy. The comparative statistical in vivo study of the kinetics of resorption and bone regeneration have shown the superiority of the composite compared to control (polymer alone). Thus the presence of Biphasic Calcium Phosphate granules in the composite has a major role for bone regeneration at the expense of the implant (buffering effect and properties of osteoconduction). An observational and functional study involving 10 patients, with a follow-up from 17 to 33 months (mean 25.7), was performed. Data were analyzed according to Good Clinical Practice and International Conference on Harmonisation. Clinical observations have revealed no complications and no serious event was reported; quantitative functional indices confirm the good observational results. The clinical study supports the functionality and performance of this new composite with properties of osteoconduction related to the osteogenicity of microporous biphasic calcium phosphate granules in the field of knee ligament fixation.

Abstract: The objective of the study was to compare clinical efficiency of the fusion after reconstruction with an anatomically shaped PEEK cage associated with a iliac crest autograft or MBCP in the treatment of cervical disc disease in randomized clinical trial. A multicente randomized, comparative and prospective study on 58 patients, with a 12 months follow up are reported. They underwent anterior cervical decompression and fusion being randomized for autologous graft or MBCP. Patients presenting purely degenerative disc disease were implanted with a PEEK cage filled with iliac crest autograft or MBCP. Pain and functionality as well as patients satisfaction were assessed through VAS, Neck Disability Index (NDI) and Patient Satisfaction index were recorded until 24 month follow-up. Radiological evaluation included plain and dynamic short X-rays at each stage of the follow up. The patients satisfaction rates was of 82% in the autograft group versus 96% in the MBCP group. Pain at the donor site was significantly more important in the autograft group at 3 weeks, 3 months and 1 year follow-up. No implant failures were recorded. Previously goat preclinical study was performed. Micro CT, light microscopy and shistomorphometry were related to the high performance of the MBCP insert for filling cage fusion, completing the clinical assessment of our clinical study. The use of MBCP insert is safe and avoids potential graft site morbidity and pain in comparison with an autologous graft procedure.

Abstract: The development of CaP ceramics involved a better control of the process of resorption and bone substitution. Micro Macroporous Biphasic CaP, (MBCP+) is a concept based on an optimum balance of the more stable phase of HA and more soluble TCP. The material is soluble and gradually dissolves in the body, seeding new bone formation as it releases Ca and P ions into the biological medium. The MBCP+ is selected for tissue engineering in a large European research program on osteoinduction and mesenchymal stem cell technology (REBORNE 7^th EU frame work program, Regenerative Bone defects using New biomedical Engineering approaches, www.reborne.org). We have optimized the matrices in terms of their physical, chemical, and crystal properties, to improve cell colonization and to increase kinetic bone ingrowth. The fast cell colonization and resorption of the material are associated to the interconnected macropores structure which enhances the resorption bone substitution process. The micropore content involves biological fluid diffusion and suitable adsorption surfaces for circulating growth factors. The bioceramics developed for this project was fully characterized using X-Ray diffraction, FTIR, X-rays micro tomography, Hg porosimetry, BET specific surface area, compressive mechanical test, and SEM. Preclinical tests on the optimized scaffold were realized in critical size defects in several sites of implantation and animals (rats, rabbits, goats, dogs).The smart scaffold has a total porosity of 73%, constituted of macropores (>100µm), mesopores of 10 to 100µm and high micropores (<10µm) content of more or less 40%. The crystal size is <0.5 to 1 µm and the specific surface area was around 6m²/g. The in vivo experiment indicated higher colonization by osteogenic cells demonstrating suitable matrices for tissue engineering. The HA/TCP ratio of 20/80 was also more efficient for combination with total bone marrow or stem cell cultivation and expansion before to be implanted.

Abstract: It was demonstrated that microstructured surfaces improve cell spreading and bone ingrowth. Particularly, the surface roughness modulates the osseointegration of orthopaedic and dental implants. We have developed an innovative grit blasting process using Biphasic Calcium Phosphate, a Resorbable Biocompatible Blast Media (RBBM). PEEK is biocompatible but an inert material, involving no direct bone bonding. Implants coming from a rabbit experimental study, were processed for X-rays Micro tomography. Light microscopy and SEM were performed.It was demonstrated in this study that the surface treatment on PEEK improve the quality of bone architecture in direct contact with the sample surface, compared to the classical surface of PEEK. These data demonstrate that PEEK rough surface obtained by RBBM blasting maintain high biocompatibility and bone osteoconduction, and promote higher stability of the implant.

Abstract: A new biphasic calcium phosphate ceramic material Hydros™ has been developed. The main attractive feature of BCP ceramic is their ability to form a strong direct bond with the host bone resulting in a strong interface. Currently, granules are more and more used in moldable, injectable bone substitutes. However, the biological behaviour of the particles can be influenced not only by chemical composition and crystallinity, but also by several parameters as microporosity and nano-micro sized particles. The aim of the study was to assess, in animal experiment, the role played by an Hydrated Putty Bioceramics (Hydros™), based on specific combination of hydrophilic micro and macrosized BCP particles, to obtain high osteogenic Injectable Bone Substitute. No sign of clinical rejection was noticed. In muscular area, no fibrous encapsulation was observed, degradation of the smaller particles is observed by macrophages and giant cells. At 12 weeks, more of 75% of BCP was resorbed. The biocompatibility and safety in human orthopaedic applications (tibial plateau fracture) has been demonstrated.