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Harikrishna Varma - One of the best experts on this subject based on the ideXlab platform.
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Hydroxyapatite-bioactive glass ceramic composite as stand-alone graft substitute for posterolateral fusion of lumbar spine: a prospective, matched, and controlled study.
Journal of spinal disorders & techniques, 2008Co-Authors: Narayana K. Acharya, Renjit J. Kumar, Harikrishna Varma, Venugopal K. MenonAbstract:STUDY DESIGN Prospective, matched, and controlled study. OBJECTIVE To evaluate the efficacy of hydroxyapatite-bioactive glass ceramic composite (Chitra-HABg) as a stand-alone graft substitute in promoting posterolateral fusion in the lumbar spine as compared with autologous bone. BACKGROUND The use of ceramics as stand-alone graft substitutes in posterolateral fusion remains controversial. The Chitra-HABg is a new composite that has undergone clinical trials in various orthopedic applications with excellent clinical and radiologic outcomes. METHODS Twenty-four patients underwent instrumented posterolateral fusion, with Chitra-HABg laid on the left intertransverse bed and autogenous graft on the right side. The primary outcome measure was radiologic consolidation of the graft, and secondary outcome measures were the work status and the Modified Oswestry Disability index. The McNamara and Student chi test were applied for statistical analysis. RESULTS Although the study was prematurely terminated owing to the high incidence of resorption of Chitra-HABg, 22 of the 24 subjects were followed-up for a minimum of 1 year. At the end of 1-year, excellent radiologic outcome was seen on the right side (autogenous graft) in all the cases, whereas 95% (21/22) of the cases had poor consolidation on the left side (Chitra-HABg). The clinical outcome was rated as good in 16/22 (73%) patients, fair in 5, and poor in only 1 patient, but this had no statistically significant association with the consolidation of the fusion mass. CONCLUSIONS This study clearly demonstrates that hydroxyapatite-bioactive glass ceramic composites (Chitra-HABg) has no role as stand-alone bone graft substitutes in posterolateral fusion of the lumbar spine, as the composite undergoes resorption without the formation of bridging callus. LEVEL OF EVIDENCE Level 1.
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Safety and efficacy of Chitra-CPC calcium phosphate cement as bone substitute
Current Science, 2006Co-Authors: Adelaide C. Fernandez, Harikrishna Varma, Mira Mohanty, Manoj KomathAbstract:Calcium phosphate cements (CPCs) have gained importance in orthopaedics and dentistry as repair materials for bony/dentinal defects. They are aqueous-based, mouldable and osteoconductive materials which set into hydroxyapatite, the basic mineral of bone and teeth. A CPC product 'Chitra-CPC' has been developed. This communication compiles the safety and efficacy evaluation of Chitra-CPC. The evaluation plan consisted of acute systemic toxicity test (in mice for systemic response), intracutaneous reactivity test (in rabbits for skin response), pyrogen test (in rabbits for presence of pyrogens) and maximization sensitization test (in guinea pigs for allergic skin response). Soft tissue response was tested by implantation in rabbit paravertebral muscle, with histological evaluation at 1, 4 and 12 weeks post-implantation. The efficacy of the product to heal bone defects was investigated by implanting in rabbit femur with hydroxyapatite ceramic granules as the control. Local effects at macroscopic and microscopic levels were assessed at time periods of 4, 12, 26 and 52 weeks post implantation. The cement did not show any adverse effects in the acute systemic toxicity. Nor did it elicit any erythemic or edematous reactivity in the intracutaneous reactivity test The maximization sensitization study did not show any adverse skin response and the pyrogen test did not evoke undue temperature rise. In the muscle implantation test, there was no haemorrhage, infection or necrosis. Localized vascularization was present near the implanted region. Chronic inflammation was observed in 1 week, which became mild by 12 weeks with the evidence of repair. Bone implantation studies showed that efficacy of Chitra-CPC and hydroxyapatite granules in bone healing is comparable. Both materials were found to be osteoconductive, but with the difference that Chitra-CPC resorbed progressively allowing simultaneous new bone formation. This proves the osteotransductivity of Chitra-CPC, which is the ideal property for a bone substitute.
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Radiological outcome of tibial plateau fractures treated with percutaneously introduced synthetic porous Hydroxyapatite granules
European Journal of Orthopaedic Surgery & Traumatology, 2005Co-Authors: K. V. Menon, Harikrishna VarmaAbstract:Synthetic bone-graft substitutes are increasingly being used in clinical orthopaedic practice. In India, Sree Chitra Tirunal Institute of Medical Sciences and Technology has pioneered the research and development of indigenous ceramic bone substitutes. The Chitra HAP is a synthetic porous Hydroxyapatite that has completed pre-market trials according to prescribed format and has also undergone limited clinical trials in humans. This study is a clinical trial to ascertain the use of the product in the treatment of cancellous impaction fractures. Twenty-eight tibial plateau fractures were treated by a standard surgical protocol using the HAP for cancellous bone augmentation. The results were evaluated by serial radiography at specified intervals up to 1 year. At 1 year the HAP appeared fully integrated with the host bone radiologically and the articular subsidence had ceased. The synthetic HAP remained radio-opaque even at 1 year. No adverse effects were noticed due to the synthetic material. It was concluded that Chitra porous HAP is a safe and useful bone graft substitute for cancellous bone augmentation in fractures.
K. V. Menon - One of the best experts on this subject based on the ideXlab platform.
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Radiological outcome of tibial plateau fractures treated with percutaneously introduced synthetic porous Hydroxyapatite granules
European Journal of Orthopaedic Surgery & Traumatology, 2005Co-Authors: K. V. Menon, H. K. VarmaAbstract:Synthetic bone-graft substitutes are increasingly being used in clinical orthopaedic practice. In India, Sree Chitra Tirunal Institute of Medical Sciences and Technology has pioneered the research and development of indigenous ceramic bone substitutes. The Chitra HAP is a synthetic porous Hydroxyapatite that has completed pre-market trials according to prescribed format and has also undergone limited clinical trials in humans. This study is a clinical trial to ascertain the use of the product in the treatment of cancellous impaction fractures. Twenty-eight tibial plateau fractures were treated by a standard surgical protocol using the HAP for cancellous bone augmentation. The results were evaluated by serial radiography at specified intervals up to 1 year. At 1 year the HAP appeared fully integrated with the host bone radiologically and the articular subsidence had ceased. The synthetic HAP remained radio-opaque even at 1 year. No adverse effects were noticed due to the synthetic material. It was concluded that Chitra porous HAP is a safe and useful bone graft substitute for cancellous bone augmentation in fractures. Les substituts osseux sont de plus en plus employés dans la pratique orthopédique ou traumatologique. L’Institut des Sciences et de la Technologie Médicales de Sree Chitra Thirunal (Inde) a initié la recherche et le développement d’un substitut osseux. Le Chitra-HAP est une hydroxyapatite poreuse synthétique qui a satisfait aux épreuves de pré-market selon les normes définies et a également été utilisé dans des essais cliniques limités chez l’homme. Cette étude a pour objet de valider l’utilisation du produit dans le traitement des fractures du plateau tibial externe avec tassement. Vingt huit fractures ont été traitées selon un protocole chirurgical standard en utilisant le Chitra-HAP pour combler la perte d’os spongieux. Les résultats ont été évalués par radiographie à intervalles réguliers jusqu’à 1 an. A un an, le Chitra-HAP semble radiologiquement entièrement intégré à l’os hôte et on n’observe pas d’enfoncement articulaire. Le Chitra-HAP synthétique reste radio-opaque même à un an. Aucun effet secondaire n’a été relevé. On peut conclure que le Chitra-HAP est un substitut de remplacement sûr et efficace pour combler les pertes de substance d’os spongieux dans les fractures du plateau tibial externe.
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Radiological outcome of tibial plateau fractures treated with percutaneously introduced synthetic porous Hydroxyapatite granules
European Journal of Orthopaedic Surgery & Traumatology, 2005Co-Authors: K. V. Menon, Harikrishna VarmaAbstract:Synthetic bone-graft substitutes are increasingly being used in clinical orthopaedic practice. In India, Sree Chitra Tirunal Institute of Medical Sciences and Technology has pioneered the research and development of indigenous ceramic bone substitutes. The Chitra HAP is a synthetic porous Hydroxyapatite that has completed pre-market trials according to prescribed format and has also undergone limited clinical trials in humans. This study is a clinical trial to ascertain the use of the product in the treatment of cancellous impaction fractures. Twenty-eight tibial plateau fractures were treated by a standard surgical protocol using the HAP for cancellous bone augmentation. The results were evaluated by serial radiography at specified intervals up to 1 year. At 1 year the HAP appeared fully integrated with the host bone radiologically and the articular subsidence had ceased. The synthetic HAP remained radio-opaque even at 1 year. No adverse effects were noticed due to the synthetic material. It was concluded that Chitra porous HAP is a safe and useful bone graft substitute for cancellous bone augmentation in fractures.
H. K. Varma - One of the best experts on this subject based on the ideXlab platform.
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Reconstruction of Iliac Crest donor site with hydroxyapatite bioactive glass ceramic composite (Chitra-HABG) - a prospective study
2012Co-Authors: Kn Acharya, H. K. Varma, Cv Mahajan, Rj Kumar, Vk MenonAbstract:Introduction Significant donor site morbidity (3–61%) has been associated with tri-cortical iliac crest bone graft harvesting and reconstruction of the defect has been shown to reduce it. Chitra-HABG (Chitra-Hydroxyapatite-Bio-active glass ceramic composite) is an indigenously developed ceramic which has been evaluated as a bone graft substitute. Aim To prospectively validate the hypothesis that iliac crest donor site morbidity is a structural issue and reconstructing the crest reduces its incidence. The study also evaluates the efficacy of Chitra - HABG as a material for reconstructing the crest. Methods 26 cases of iliac crest reconstruction with Chitra-HABG blocks were prospectively evaluated. Outcome measures were donor site morbidity as assessed clinically and radiological assessment for ceramic incorporation, dissolution, fragmentation and migration. Results At the end of one year from surgery, 25 patients (96.15%) had no donor site pain. Radiological evaluation showed that ceramic incorporation was complete in 21 cases, partial in three and absent in two. Partial dissolution of ceramic was noticed in three patients and migration in one. Conclusion The present study validates our hypothesis that the donor site morbidity following tri-cortical iliac crest graft harvesting is probably a structural issue and it can be reduced by reconstruction of the defect. It also highlights the fact that the Chitra-HABG block is an excellent material for reconstruction of the iliac crest defect, as it gets incorporated into the surrounding bone without adverse effects. Significance Study describes a simple and effective method to decrease iliac crest donor site morbidity. Level of evidence: IV Study Design Prospective study. Summary Prospectively evaluate the efficacy of Chitra-HABG blocks for iliac crest reconstruction.
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Radiological outcome of tibial plateau fractures treated with percutaneously introduced synthetic porous Hydroxyapatite granules
European Journal of Orthopaedic Surgery & Traumatology, 2005Co-Authors: K. V. Menon, H. K. VarmaAbstract:Synthetic bone-graft substitutes are increasingly being used in clinical orthopaedic practice. In India, Sree Chitra Tirunal Institute of Medical Sciences and Technology has pioneered the research and development of indigenous ceramic bone substitutes. The Chitra HAP is a synthetic porous Hydroxyapatite that has completed pre-market trials according to prescribed format and has also undergone limited clinical trials in humans. This study is a clinical trial to ascertain the use of the product in the treatment of cancellous impaction fractures. Twenty-eight tibial plateau fractures were treated by a standard surgical protocol using the HAP for cancellous bone augmentation. The results were evaluated by serial radiography at specified intervals up to 1 year. At 1 year the HAP appeared fully integrated with the host bone radiologically and the articular subsidence had ceased. The synthetic HAP remained radio-opaque even at 1 year. No adverse effects were noticed due to the synthetic material. It was concluded that Chitra porous HAP is a safe and useful bone graft substitute for cancellous bone augmentation in fractures. Les substituts osseux sont de plus en plus employés dans la pratique orthopédique ou traumatologique. L’Institut des Sciences et de la Technologie Médicales de Sree Chitra Thirunal (Inde) a initié la recherche et le développement d’un substitut osseux. Le Chitra-HAP est une hydroxyapatite poreuse synthétique qui a satisfait aux épreuves de pré-market selon les normes définies et a également été utilisé dans des essais cliniques limités chez l’homme. Cette étude a pour objet de valider l’utilisation du produit dans le traitement des fractures du plateau tibial externe avec tassement. Vingt huit fractures ont été traitées selon un protocole chirurgical standard en utilisant le Chitra-HAP pour combler la perte d’os spongieux. Les résultats ont été évalués par radiographie à intervalles réguliers jusqu’à 1 an. A un an, le Chitra-HAP semble radiologiquement entièrement intégré à l’os hôte et on n’observe pas d’enfoncement articulaire. Le Chitra-HAP synthétique reste radio-opaque même à un an. Aucun effet secondaire n’a été relevé. On peut conclure que le Chitra-HAP est un substitut de remplacement sûr et efficace pour combler les pertes de substance d’os spongieux dans les fractures du plateau tibial externe.
Girdhar G Agrawal - One of the best experts on this subject based on the ideXlab platform.
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critical evaluation of clinical results with ttk sree Chitra valve
Indian Journal of Thoracic and Cardiovascular Surgery, 2005Co-Authors: Lalit Mohan Joshi, Sushil Kumar Singh, Salman Siddiqi, Sanjay Pandey, Girdhar G AgrawalAbstract:Background: Rheumatic heart disease is the major indication for valve surgery in India. Majority of these patients belong to the low socio-economic groups, long term clinical results with TTK-Sree Chitra valve being presented herewith as an affordable option. Method: Data was evaluated retrospectively to determine long term clinical outcome of 178 TTK-Sree Chitra valve implanted at out institution from January, 1993 through December, 2003. Mitral (n=78), Aortic (n=40) and Double valve replacement (n=30) were performed. Follow up was sought five times in this period. Total follow up was 448±2.8 patient years. Follow up was 94% complete. Results: Early mortality was 2.02% ( 3 patients). Eight (5.4%) late deaths, of 13 total deaths, were due to valve related events (5.41%). Structural deterioration, non structural dysfunction, stuck valve and prosthetic valve endocarditis were not observed. Actuarial freedom from reoperation at 10 years was 100% for valves at both positions. Actuarial survival rate at 10 years was 89.87±7.2%. Conclusions: Overall TTK-Sree Chitra valve is an excellent substitue, and cost effective. (Ind J Thorac Cardiovasc Surg, 2005; 21: 15–17)
William P. Mccord - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic diversity of endangered and critically endangered southeast asian softshell turtles trionychidae Chitra
Biological Conservation, 2002Co-Authors: Tag N. Engstrom, Bradley H. Shaffer, William P. MccordAbstract:The intense exploitation of turtles in Asian markets has contributed to declines in turtle populations across the continent. Threequarters of Asia’s turtles are threatened and half are endangered. A recent workshop on the Asian turtle crisis identified taxonomic studies of widespread species as a priority for research because these low risk species may include unrecognized, narrowly distributed taxa of much higher concern. Chitra indica is a widely exploited softshell turtle (family Trionychidae) found across southern Asia. Individuals from Thailand have been described as a separate species, Chitra Chitra, but this has not been universally accepted, and many sources consider Chitra monotypic. Phylogenetic analysis of sequence data from the mitochondrial ND4 gene revealed three deeply divergent, monophyletic lineages within Chitra: C. indica, C. Chitra, and a third unnamed form from Myanmar. This new form is probably Critically Endangered, which highlights the importance of systematic studies in determining conservation priorities. # 2002 Elsevier Science Ltd. All rights reserved.
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MOLECULAR SUPPORT FOR THE TAXONOMIC CONCLUSIONS OF McCORD AND PRITCHARD (2002), REGARDING Chitra
2002Co-Authors: Tag N. Engstrom, William P. MccordAbstract:McCord and Pritchard (2002) have presented a taxonomic revision of the trionychid turtle genus Chitra, in which they describe one new species (Chitra vandijki) from Myanmar, name two subspecies withinChitraChitra and considerChitraindica to be monotypic across its wide range from Pakistan to Bangladesh. Here we present DNA sequence data from mitochondrial ND4 gene, which support their taxonomic conclusions. There is deep molecular divergence among the three recognized species ofChitra and a low level of geographically structured variation within Chitra Chitra corresponding with mainland and island subspecies. In contrast, Chitra indica shows almost no molecular variation across its broad range from Pakistan to Bangladesh. This apparent genetic uniformity is an interesting biogeographic phenomenon, which merits further investigation.