Experimental replacement of esophagus with a short segment of trachea.

BACKGROUND: Segmental resection of esophagus with primary anastomosis is prohibited because of the risk of dehiscence. We previously have shown that replacement of a segment of cervical esophagus with a tracheal segment of the same length could successfully be performed in a canine model. In this study, we sought to assess the feasibility of replacement of the esophageal defect with a shorter segment of trachea. METHODS: In five mongrel dogs weighting 20-30 kg, under general anesthesia and after a cervical incision, 8 cm of the cervical esophagus was resected and replaced by a 4-cm segment of the adjacent trachea. The animals were evaluated clinically for signs and symptoms of stenosis and dehiscence and then euthanized after 2 mo of follow-up. RESULTS: All dogs recovered from surgery and started regular diet on the seventh postoperative day. No clinical or endoscopic sign of stenosis or voice change was seen. Squamous metaplasia and atrophy of mucosal glands and cartilage were detected in the histopathologic examination of the replaced segments. CONCLUSIONS: Replacement of a cervical esophageal defect with a shorter segment of trachea can be performed successfully in dogs. This procedure can be potentially used for the treatment of cervical esophageal lesions in humans.

A comparative study of red and blue light-emitting diodes and low-level laser in regeneration of the transected sciatic nerve after an end to end neurorrhaphy in rabbits.

This study aimed at evaluating the effects of red and blue light-emitting diodes (LED) and low-level laser (LLL) on the regeneration of the transected sciatic nerve after an end-to-end neurorrhaphy in rabbits. Forty healthy mature male New Zealand rabbits were randomly assigned into four experimental groups: control, LLL (680 nm), red LED (650 nm), and blue LED (450 nm). All animals underwent the right sciatic nerve neurotmesis injury under general anesthesia and end-to-end anastomosis. The phototherapy was initiated on the first postoperative day and lasted for 14 consecutive days at the same time of the day. On the 30th day post-surgery, the animals whose sciatic nerves were harvested for histopathological analysis were euthanized. The nerves were analyzed and quantified the following findings: Schwann cells, large myelinic axons, and neurons. In the LLL group, as compared to other groups, an increase in the number of all analyzed aspects was observed with significance level (P < 0.05). This finding suggests that postoperative LLL irradiation was able to accelerate and potentialize the peripheral nerve regeneration process in rabbits within 14 days of irradiation.

Evaluation of low-level laser therapy, platelet-rich plasma, and their combination on the healing of Achilles tendon in rabbits.

Tendon repair is still one of the challenges for rehabilitation. Various treatments for tendon injuries have been used in recent decade. This study was established to investigate the effects of low-level laser therapy (LLLT), platelet-rich plasma (PRP) treatment alone, and using combined method on the healing of Achilles tendon in rabbits. Seventy-two healthy mature male white New Zealand rabbits were divided randomly into four groups of 18 animals each: control: partial tenotomy with no treatment, only 1 mL normal saline was injected on days 1, 8, and 15 at the site of splitting; PRP: partial tenotomy with PRP treatment on days 1, 8, and 15 at the site of splitting; LLLT: partial tenotomy with LLLT (K30 hand-held probe, AZOR, Technica, Russia, 650 nm, 30 mW, surface area = 1 cm(2), 60 S/cm(2), energy density = 1.8 J/cm(2)) for 15 consecutive days; LLLT + PRP: partial tenotomy with LLLT + PRP. At the end of trial, the rabbits were euthanatized and tendon specimens were harvested and were submitted for histopathological evaluation, hydroxyproline levels, and biomechanical measurement. The Tukey post hoc test was performed. The results for these parameters showed that PRP or LLLT alone has significant advantages over untreated animals (P < 0.05). Furthermore, it was found that the combined treatment with PRP and LLLT is even more efficient. There was no significant difference (P > 0.05) between the two groups of LLLT and PRP. However, the treatments combining PRP and LLLT showed significant results in comparison of PRP or LLLT alone (P < 0.05). Our results demonstrate that the healing time of injured tendon decreases by using the two therapies combined.

Physico-chemical and in vitro biological evaluation of strontium/calcium silicophosphate glass.

Strontium is known to reduce bone resorption and stimulate bone formation. Incorporation of strontium into calcium phosphate bioceramics has been widely reported. In this work, calcium and calcium/strontium silicophosphate glasses were synthesized from the sol-gel process and their rheological, thermal, and in vitro biological properties were studied and compared to each other. The results showed that the gel viscosity and thus the rate of gel formation increased by using strontium in glass composition and by increasing aging temperature. In strontium-containing glass, the crystallization temperature increased and the type of the crystallized phase was different to that of strontium-free glass. Both glasses favored precipitation of calcium phosphate layer when they were soaked in simulated body fluid; however strontium seemed to retard the rate of precipitation slightly. The in vitro biodegradation rate of the strontium/calcium silicophosphate glass was higher than that of strontium-free one. The cell culture experiments carried out using rat calvaria osteoblasts showed that the incorporation of strontium into the glass composition stimulated proliferation of the cells and enhanced their alkaline phosphatase activity, depending on cell culture period.

The histological and clinical effects of 630 nanometer and 860 nanometer low-level laser on rabbits' ear punch holes.

Low-level laser therapy (LLLT) studies on the musculoskeletal and cartilage tissues of rabbits have reported conflicting results. We aimed to investigate the effects of 630 nm and 860 nm low-level laser on injured rabbit cartilage. After punching 5 mm holes in both ears of ten rabbits, we grouped the rabbits randomly. The punched holes of the laser-treated group were irradiated with 630 nm and 860 nm diode laser on days 3-5 and then every other day until day 20. In both laser and control groups, the hole diameters were measured weekly. Histological evaluation was carried out on day 30. The inter-group difference in hole diameters was not significant. Mann-Whitney U tests showed significant inter-group differences in histological variables related to chondrocyte production and organization, growth rate, granulation tissue and pseudocarcinomatosis. LLLT improved cartilage formation and reduced inflammation and formation of granulation tissue. More accurate results on its healing effects warrant studies with larger sample sizes.

Comparison and Evaluation of the Low-Level Laser and the Red and Blue LED Effects on Wound Healing in Rabbit.

Introduction: Wound healing is a dynamic, interactive process to achieve the restoration of skin integrity and proper function after damage. Applying a low-level laser (LLL) and light emitting diodes (henceforth LEDs) is introduced in previous studies to accelerate the process of wound healing. The aim of this study is to compare the effect of the LLL and LEDs on wound healing in rabbits. Methods: Full thickness same size square excision wounds were created on the dorsum of the rabbits. Twenty rabbits were randomly divided into four groups, according to the treatment received. Group 1: the AlGalInP (aluminium gallium indium phosphide) laser (4 J/cm²); group 2: the red LED (30 J/cm²); group 3: the blue LED (60 J/cm²) and group 4, as the control group, was not irradiated. After 30 days, the wounds were evaluated both morphologically and histopathologically. Statistical significance was defined as a P value of less than 0.05. Results: All interfering methods including the LLL and LEDs had better outcome compared with the control group of both sizes and histopathologic features. The red laser group showed better results compared to the control group and either the LED groups. Comparing LEDs, the red LED performed better than the blue LED. Conclusion: This study confirmed the significant effects of the LLL and LEDs on wound healing. Comparing the LLL and LED, the LED may be a better choice, especially for bedridden or debilitated patients. The LED may also more cost effective in wound healing in comparison with the LLL.

Therapeutic effects of simultaneous Photobiomodulation therapy (PBMT) and Meloxicam administration on experimental acute spinal cord injury: Rat animal model.

STUDY DESIGN: Application of Photobiomodulation therapy (PBMT) and meloxicam in acute spinal cord injury, functional recovery and histological evaluation. OBJECTIVE: Evaluation of the effect of simultaneous PBMT and meloxicam on treatment of acute experimental spinal cord injury and comparing it with the effect of application of each of them separately. SETTING: The study was conducted at the Department of Surgery & Radiology, Faculty of Veterinary Medicine and Institute of Biomedical Research, University of Tehran, Tehran, Iran. METHODS: Twenty four rats were used in this study. A compression injury was induced to the T8-T9 segment of the spinal cord of rats using a Fogarty embolectomy catheter. Rats were randomly divided into 4 groups including: Control group, PBMT (810 nm-200 mw-8 s-2 weeks) group, Meloxicam (1 mg/kg) group, and PBMT and Meloxicam (mixed) group. After inducing injury, hind limb performance of the rats was evaluated, using BBB test and then treatment intervention was performed and continued for 2 weeks. RESULTS: Four  weeks after injury induction, BBB test results were significantly higher in all treatment groups in comparison to control group, however, there were no significant differences among the treatment groups. In addition, histological findings revealed no significant difference between all 4 study groups. CONCLUSION: According to the results of this study we can conclude that simultaneous and separate application of PBMT and Meloxicam play an effective role in treatment of acute spinal cord injuries.

Investigation of an effervescent additive as porogenic agent for bone cement macroporosity.

Calcium phosphate cements (CPCs) are biocompatible and osteoconductive materials used in dental, craniofacial and orthopaedic applications. One of the most important advantages of these materials is their replacement with bone followed by resorption. Already several attempts have been made to improve the resorption behaviour of calcium phosphate cements by increasing the porosity of the material. In this investigation a mixture of NaHCO(3) and citric acid monohydrate was added to the apatite cement component as an effervescent additive for producing interconnected macropores into the cement matrix. Mercury intrusion porosimetry was employed to determine pore volume and pore size distribution in the calcium phosphate cement (CPC) samples. Results showed that addition of only 10 wt % of the effervescent additive (based on the cement powder) to the CPC components lead to producing about 20 V % macropores (with the size of 10 to 1000 mum) into the cement structure. The setting time was measured in an incubator at 37 degrees C and decreased from 40 min for additive-free CPC to about 14 min for CPC containing effervescent additive. Other properties of the CPCs such as compressive strength, phase composition, microstructure morphology and dissolution behavior were evaluated after immersing them in a simulated body fluid solution. The results showed that the rate of formation of poor crystalline apatite phase have been improved by production of macroporosity into the cement matrix.

The effects of loading time on osseointegration and new bone formation around dental implants: a histologic and histomorphometric study in dogs.

BACKGROUND: Immediate loading of dental implants has been introduced as a method of reducing implant treatment time without compromising its prognosis. In this research, the effects of loading time on the amount of bone-to-implant contact and bone formation around dental implants were evaluated histologically. METHODS: Three months prior to implantation, the lower premolar teeth of 15 dogs were extracted. Three or four dental implants were placed in the healed extraction sites for each dog (N = 48). Dividing the dogs into three groups, the implants were either loaded 48 hours or 1 week later with metallic or prefabricated acrylic crowns or were left unloaded until the time of sacrifice. Three months after implant insertion, the animals were sacrificed and samples were investigated to define the amount of bone-to-implant contact, lamellar and woven bone percentage, and local inflammation of the newly formed bone. RESULTS: No significant difference in the observed criteria was reported among the three groups (P >0.05); however, the unloaded group had the highest degree of bone-to-implant contact and the group loaded 48 hours after the primary implant insertion had the least. The prosthesis type had no significant effect on the implant success rate (P >0.05). The lamellar and woven bone percentage of newly formed bone also did not differ in the three groups (P >0.05). One implant from each group failed in this study. CONCLUSION: Loading time does not seem to significantly affect the degree of osseointegration and bone-to-implant contact and the composition of newly formed bone around dental implants.

Value of color Doppler ultrasonography and radiography for the assessment of the cancellous bone scaffold coated with nano-hydroxyapatite in repair of radial bone in rabbit.

PURPOSE: To evaluate the osteo-regenerative capacity of proprietary bone grafting material as a bone defect filler and osteogenetic stimulation to speed up bone healing too. METHODS: Eighteen adult male New Zealand white rabbits were anesthetized and a segmental full thickness bone defect of 10 mm in length was created in the middle of the right radial shaft in all rabbits. They were divided into two groups of 9 rabbits. Group I was considered as control and the fractured site was fixed using finger bone plate with 4 screws, whereas the cancellous bone scaffold coated with Nano-Hydroxyapatite was used to fill the gap after fracture fixation in Group II. Radiography, two dimensional and color Doppler ultrasonography were done before and after creating defects and on 0, 15, 30, 60 and 90 days to evaluate local reaction as far as new blood vessels network and callus formation are observed. RESULTS: On the radiographs during the whole process, bone repair in Group I was not as perfect as those in Group II samples and trace of internal callus filled the gap incompletely in 60 days in Group I, whereas in Group II internal callus almost was formed on 30 days and in addition intercortical callus was seen supporting to cover and filled the gap completely in this group in 60 day; Sonographic findings confirmed the protrusion of newly formed blood vascular network in 30 days in Group I and from 15 days in Group II and remarkably increased till end of observation period. CONCLUSIONS: The nano-hydroxyapatite with more features and shorter in time, made possible the reconstruction of bone tissue and alternative techniques as well as previous bone graft, also radiography and ultrasonography are reliable techniques to trace local reaction at proper time.

Mechanical properties of radial bone defects treated with autogenous graft covered with hydroxyapatite in rabbit.

PURPOSE: To determine biomechanical property of autogenous bone graft covered with hydroxyapatite in the defect of radial bone in rabbit. METHODS: Eighteen adult male New Zealand white rabbits were used which were divided into three groups (I, II, III) of six rabbits each. A segmental bone defect of 10 mm in length was created in the middle of the right radial shaft under general effective anesthesia in all rabbits and were stabilized using mini-plate with four screws. The defects In group I were left as such without filler, whereas in group II the defect were filled up with harvested 10 mm rib bone and in group III the defect were packed with rib bone covered with nano-hydroxyapatite. All rabbits in three groups were divided into two subgroups (one month and three months duration with three rabbits in each one). RESULTS: The mechanical property and the mean load for fracturing normal radial bone was recorded 388.2 ± 6 N whereas it was 72.4 ± 12.8 N for group I in 1 month duration which was recorded 182.4 ± 14.2 N for group II and 211.6 ± 10.4 N for group III at the end of 1 month. These values were 97.6 ± 10.2 N for group I and 324.6 ± 8.2 N for group II and 372.6 ± 17.4 N for group III at the end of three months after implantation. CONCLUSION: Implantation of autologous graft covered with hydroxyapatite indicated to have positive effect in integral formation of qualitative callus at the site of fracture and early re-organization of callus to regain mechanical strength too.

Using tracheal segments for replacement of cervical oesophagus: an experimental study.

OBJECTIVES: Segmental resection and anastomosis of oesophageal lesions are not performed as a routine clinical practice because of complications and associated problems, whereas tracheal resection and anastomosis are a routine clinical practice. In this experimental study, we resected a segment of cervical oesophagus and replaced it with a tracheal segment. METHODS: In eight dogs (mixed races), weighing 20-30 kg, ageing 1-2 years, under general anaesthesia, through a cervical incision, 5 cm of cervical trachea was separated while preserving its attachments to surrounding fibroareolar tissues. Afterwards, 5 cm of the oesophagus was resected and replaced with a prepared segment of the trachea. Oral liquids were started at the first post-operative day; the animals were kept for 2 months and then euthanized. Quality of swallowing and voice were evaluated. After an autopsy, anastomoses were examined grossly and histopathologically. RESULTS: No complications occurred during surgery. Swallowing function and voice were normal in all eight dogs after the operation. No sign of aspiration was seen in clinical and radiographic examinations after starting oral diet. In autopsy examination, anastomoses were patent without narrowing or abnormal mucosal changes. Remarkable histopathological findings in replaced tracheal segments were squamous metaplasia, atrophy and degeneration of mucosal glands and degeneration of cartilages. CONCLUSIONS: Replacement of a segment of the oesophagus with an autogenous tracheal segment is a practical procedure with low complications and can probably be used for the treatment of cervical oesophageal lesions in human beings.

Effect of decompressive hemicraniectomy on mortality of malignant middle cerebral artery infarction.

BACKGROUND: Increasing intracranial pressure (ICP) is one of the leading causes of mortality in patients with malignant infarction of the middle cerebral artery (MCA). We prospectively evaluated patients with MCA infarction for one month survival after decompressive hemicraniectomy. METHODS: This study was conducted at Alzahra University Hospital, Isfahan (Iran). Twenty patients with infarction in total MCA distribution area, resulting in midline shift of brain tissue for greater than 5mm, underwent decompressive hemicraniectomy. Mortality rate was estimated one month after surgery. RESULTS: Patients were 8 (40%) males and 12 (60%) females with a mean age of 49.9 ± 3.8 (25 to 70) years. Left and right MCA were involved in 7 (35%) and 13 (65%) patients, respectively. Four (20%) patients died within one month after surgery (3 females and one male, mean age of 59.0 ± 4.5 vs. 47.6 ± 3.4 in survived patients, p < 0.001). The mean of baseline Glasscow Coma Scale (GCS) score estimated 8.60 ± 1.55 in survived patients and 6.75 ± 0.95 in patients who died (p < 0.05). CONCLUSIONS: The survival rate of malignant MCA infarction treated with decompressive hemicraniectomy was the same as previous reports. MCA infarction mortality increased with age and lower admission GCS score.

Cerebral vasospasm following traumatic subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm is a preventable cause of death and disability in patients who experience aneurysmal subarachnoid hemorrhage (SAH). The aim of this study is to investigate the incidence of cerebral vasospasm following traumatic SAH and its relationship with different brain injuries and severity of trauma. METHODS: This cross-sectional study was conducted from October 2006 to March 2007 in department of Neurosurgery in Al-Zahra Hospital. Consecutive head-injured patients who had SAH on the basis of an admission CT scan were prospectively evaluated. The severity of the trauma was evaluated by determining Glasgow Coma Scale (GCS) score on admission. Transcranial Doppler ultrasonography evaluations were performed at least 48 hours after admission and one week thereafter. Vasospasm in the MCA and ACA was defined by mean flow velocity (FV) of more than 120 cm/sec with a Lindegaard index (MVA/ICA FV ratio) higher than 3. Basilar artery vasospasm was defined by FV higher than 85 cm/sec. RESULTS: Seventy seven patients with tSAH were enrolled from whom 13 were excluded. The remaining were 52 (81.2%) men and 12 (18.7%) women, with a mean age of 37.89 years. Trauma was severe in 11 (17.2%), moderate in 13 (20.3%), and mild in 40 (62.5%) patients. From all, 27 patients (42.1%) experienced at least one vasospasm during the study period and MCA vasospasm was the most common in the first and second weeks (55.5%). CONCLUSIONS: Traumatic SAH is associated with a high incidence of cerebral vasospasm with a higher probability in patients with severe TBI.

Histopathological evaluation of pulpotomy with Er,Cr:YSGG laser vs formocresol.

The purpose of this study was to histologically investigate whether pulpotomy with Er,Cr:YSGG laser is an acceptable alternative for formocresol. Pulpotomy of 48 dog's primary canine teeth was performed with formocresol or Er,Cr:YSGG laser. Histological evaluations on hematoxylin and eosin-stained pulp tissues were made by an optical microscope 7 or 60 days later. Statistical analysis was performed with Fisher's exact test, Mann-Whitney U test, and Student's t test. Seven days after pulpotomy, samples treated with laser had significantly favorable histological features in the following measures: continuity of odontoblastic layer (P<0.001), presence of hemorrhage (P<0.008), amount of inflammation (P<0.002), tissue necrosis (P<0.001), internal resorption (P<0.002), level of vascularization (P<0.002), and size of abscess (P<0.041). Similar results were observed 60 days after pulpotomy, except that the differences were not mostly significant due to natural exfoliation of 16 teeth. In conclusion, Er,Cr:YSGG laser system is an acceptable alternative for formocresol in pulpotomy of deciduous teeth.

Value of color Doppler ultrasonography and radiography for the assessment of the cancellous bone scaffold coated with nano-hydroxyapatite in repair of radial bone in rabbit / Valor da ultrassonografia Doppler em cores e da radiografia na avaliação da capacidade osteo-regenerativa da nano-hidroxiapatita no reparo de osso radial em coelho

PURPOSE: To evaluate the osteo-regenerative capacity of proprietary bone grafting material as a bone defect filler and osteogenetic stimulation to speed up bone healing too. METHODS: Eighteen adult male New Zealand white rabbits were anesthetized and a segmental full thickness bone defect of 10 mm in length was created in the middle of the right radial shaft in all rabbits. They were divided into two groups of 9 rabbits. Group I was considered as control and the fractured site was fixed using finger bone plate with 4 screws, whereas the cancellous bone scaffold coated with Nano-Hydroxyapatite was used to fill the gap after fracture fixation in Group II. Radiography, two dimensional and color Doppler ultrasonography were done before and after creating defects and on 0, 15, 30, 60 and 90 days to evaluate local reaction as far as new blood vessels network and callus formation are observed. RESULTS: On the radiographs during the whole process, bone repair in Group I was not as perfect as those in Group II samples and trace of internal callus filled the gap incompletely in 60 days in Group I, whereas in Group II internal callus almost was formed on 30 days and in addition intercortical callus was seen supporting to cover and filled the gap completely in this group in 60 day; Sonographic findings confirmed the protrusion of newly formed blood vascular network in 30 days in Group I and from 15 days in Group II and remarkably increased till end of observation period. CONCLUSIONS: The nano-hydroxyapatite with more features and shorter in time, made possible the reconstruction of bone tissue and alternative techniques as well as previous bone graft, also radiography and ultrasonography are reliable techniques to trace local reaction at proper time.

OBJETIVO: Avaliar a capacidade osteo-regenerativa de biomaterial no preenchimento de defeito ósseo e como estímulo osteogênico para acelerar a cicatrização óssea. ÉTODOS: Dezoito coelhos brancos, Nova Zelandia, adultos, machos foram anestesiados e um defeito ósseo segmentar de toda a espessura e 10 mm de comprimento foi criado no meio do eixo do osso radial direito de todos os coelhos. Os animais foram distribuídos em dois grupos de nove: Grupo I foi considerado como controle e o local da fratura foi fixado usando placa de dedo de osso com quatro parafusos, enquanto o molde de osso esponjoso revestido com nano-hidroxiapatita foi usado para preencher o espaço após fixação da fratura no Grupo II. Radiografia, bidimensional e ultrassonografia Doppler colorida foi feita antes e após criar os defeitos e nos dias 0, 15, 30, 60 e 90 para avaliar a reação local tais como nova rede vascular e formação do calo ósseo. RESULTADOS: Nas radiografias durante todo o processo, o reparo ósseo no Grupo I não foi perfeito como no Grupo II; amostras e traços de calo ósseo preencheram o espaço de forma incompleta em 60 dias no Grupo I, enquanto no Grupo II o calo ósseo interno foi quase formado em 30 dias e, além disso, calo intercortical foi visto apoiar para revestir e preencher o espaço completamente em 60 dias; nos achados ultrassonográficos a protrusão da rede vascular neoformada em 30 dias no Grupo I e a partir de 15 dias no Grupo II e acentuado aumento até o fim do período de observação. CONCLUSÕES: A nano-hidroxiapatita, com mais propriedade e menor período de tempo, tornou possível a reconstrução de tecido ósseo e técnicas alternativas como o enxerto ósseo prévio, assim como a radiografia e a ultrassonografia são técnicas confiáveis para traçar a reação local em tempo adequado.

Mechanical properties of radial bone defects treated with autogenous graft covered with hydroxyapatite in rabbit / Propriedades mecânicas de defeito de osso radial tratado com enxerto autógeno coberto com nano-hydroxyapatite em coelho

PURPOSE: To determine biomechanical property of autogenous bone graft covered with hydroxyapatite in the defect of radial bone in rabbit. METHODS: Eighteen adult male New Zealand white rabbits were used which were divided into three groups (I, II, III) of six rabbits each. A segmental bone defect of 10 mm in length was created in the middle of the right radial shaft under general effective anesthesia in all rabbits and were stabilized using mini-plate with four screws. The defects In group I were left as such without filler, whereas in group II the defect were filled up with harvested 10 mm rib bone and in group III the defect were packed with rib bone covered with nano-hydroxyapatite. All rabbits in three groups were divided into two subgroups (one month and three months duration with three rabbits in each one). RESULTS: The mechanical property and the mean load for fracturing normal radial bone was recorded 388.2±6 N whereas it was 72.4±12.8 N for group I in 1 month duration which was recorded 182.4±14.2 N for group II and 211.6±10.4 N for group III at the end of 1 month. These values were 97.6±10.2 N for group I and 324.6±8.2 N for group II and 372.6±17.4 N for group III at the end of three months after implantation. CONCLUSION: Implantation of autologous graft covered with hydroxyapatite indicated to have positive effect in integral formation of qualitative callus at the site of fracture and early re-organization of callus to regain mechanical strength too.

OBJETIVO: Determinar as propriedades biomecânicas de enxerto ósseo autógeno coberto com hidroxiapatita em defeito do osso radial em coelhos. MÉTODOS: Foram utilizados 18 coelhos adultos, machos, brancos, Nova Zelândia, distribuídos em três grupos (I, II, III) de seis coelhos cada. Um defeito segmentar de 10 mm de comprimento foi criado no meio do eixo radial direito sob anestesia geral efetiva em todos os coelhos e foram fixados usando mini-placa com quatro parafusos. Os defeitos no grupo I foram deixados sem preenchimento, enquanto no grupo II o defeito foi preenchido com 10 mm de costela recoberta com nano-hidroxiapatita. Os coelhos nos três grupos foram distribuídos em dois subgrupos (Um e três meses, com três coelhos cada um). RESULTADOS: A propriedade mecânica e a média do peso para fraturar o osso radial normal foi 388,2±6 N, enquanto para o Grupo I, com um mês foi 72,4±12,8 N, para o grupo II 182,4±14,2 N e para o Grupo III 211,6±10,4 N. Após três meses de implantação, os valores foram 97,6±10,2 N para o Grupo I, 324,6±8,2 N para o Grupo II e 372,6±17,4 N para o Grupo III. CONCLUSÃO: A implantação de enxerto autólogo recoberto com hidroxiapatita indicou ter um efeito positivo na formação integral qualitativa do calo ósseo no local da fratura e precoce reorganização do calo com recuperação da força mecânica.