Raul Bolliger Neto

Estudo biomecânico de resistência à tração de âncoras metálicas de sutura em diferentes ângulos de inserção

O objetivo deste trabalho e verificar se o ângulo de insercao das âncoras de sutura interfere na sua resistencia quando submetidas a uma forca de tracao constante. Foram realizados 20 ensaios com âncoras metalicas de sutura inseridas em 4 angulacoes diferentes (30°, 45°, 60°, 90°), em osso de cadaver humano (femur distal) e mais 20 ensaios em osso artificial (SawboneTM). Os testes foram realizados na Maquina Universal de Ensaios modelo Kratos, sendo as âncoras tracionadas a 90° em relacao ao seu plano de insercao na superficie ossea. Os valores encontrados no osso de cadaver humano nao foram estatisticamente significantes, ou seja, o ângulo de insercao nao influiu na resistencia a tracao. No osso artificial verificou-se que houve maior resistencia na insercao a 90o, com relevância estatistica em relacao aos demais ângulos testados.

Análise comparativa do controle postural de indivíduos com e sem lesão do ligamento cruzado anterior do joelho

Standing balance is the process which keeps the pressure center, vertical projection of the centre of gravity on ground inside the body weight-bearing. This study evaluates posture control in patients with unilateral lesion of anterior cruciate ligament of knee and in healthy individuals (control group), through parameters of pressure center. Nineteen healthy individuals (11 men, 8 women, age ranged from 18 to 30 years) and nineteen patients with unilateral lesion of anterior cruciate ligament of knee (18 men, 1 woman, age ranged from 15 to 33 years) were evaluated by FSCAN MAT® version 3848 (Tekscan® , Boston, MA, USA) sensors. Four different static tests with unilateral bearing were made, alternating the sides (dominant and non dominant) and keeping open or closed eyes. The parameters were calculated: total length path, antero-posterior amplitude, medio-lateral amplitude and maximum speed of pressure center. The results have pointed out that: the dominance of inferior limbs does not affect in a special way the balance of healthy individuals, the vision is an important factor in posture control and the unilateral lesion of anterior cruciate ligament of knee affects the balance in unilateral weight bearing, on both sides, however more evident on the side with the lesion.

Pedobarometric evaluation of the normal adult male foot.

Static and dynamic pedobarometric evaluations were performed on the feet of 100 normal adult white men aged from 20 to 49 years old (mean = 29.9±6.9), using version 3.848 of the F-SCAN system. All evaluations were performed using new pressure sensor insoles with standardized conditions. Maximum vertical forces and plantar peak pressure measurements were taken during 7.88 seconds each of walking in a straight line at subjects own pace and standing. Feet were separated based on their side and lower limb dominance. The means of three consecutive and three alternate tests provided quantitative data. Maximum static and vertical dynamic forces were found to be greater on the dominant side and were significantly correlated with body weight. There were significant differences between dominant and non-dominant sides in static plantar peak pressure evaluations at the forefoot and midfoot, and in the dynamic evaluations at the midfoot. There was a significant correlation between dynamic plantar peak pressures at the midfoot and body weight.

Development and evaluation of a head-controlled human-computer interface with mouse-like functions for physically disabled users

OBJECTIVES The objectives of this study were to develop a pointing device controlled by head movement that had the same functions as a conventional mouse and to evaluate the performance of the proposed device when operated by quadriplegic users. METHODS Ten individuals with cervical spinal cord injury participated in functional evaluations of the developed pointing device. The device consisted of a video camera, computer software, and a target attached to the front part of a cap, which was placed on the user’s head. The software captured images of the target coming from the video camera and processed them with the aim of determining the displacement from the center of the target and correlating this with the movement of the computer cursor. Evaluation of the interaction between each user and the proposed device was carried out using 24 multidirectional tests with two degrees of difficulty. RESULTS According to the parameters of mean throughput and movement time, no statistically significant differences were observed between the repetitions of the tests for either of the studied levels of difficulty. CONCLUSIONS The developed pointing device adequately emulates the movement functions of the computer cursor. It is easy to use and can be learned quickly when operated by quadriplegic individuals.

EXPERIMENTAL DETERMINATION OF BONE CORTEX HOLDING POWER OF ORTHOPEDIC SCREW

Cylindrical specimens of bone measuring 15 mm in diameter were obtained from the lateral cortical layer of 10 pairs of femurs and tibias. A central hole 3.2 mm in diameter was drilled in each specimen. The hole was tapped, and a 4.5 mm cortical bone screw was inserted from the outer surface. The montage was submitted to push-out testing up to a complete strip of the bone threads. The cortical thickness and rupture load were measured, and the shear stress was calculated. The results were grouped according to the bone segment from which the specimen was obtained. The results showed that bone cortex screw holding power is dependent on the bone site. Additionally, the diaphyseal cortical bone tissue is both quantitatively and qualitatively more resistant to screw extraction than the metaphyseal tissue.

Median nerve fascicle transfer versus ULNAR nerve fascicle transfer to the biceps motor branch in C5-C6 and C5-C7 brachial plexus injuries: Nonrandomized prospective study of 23 consecutive patients

The purpose of this study was to observe whether the results of the median nerve fascicle transfer to the biceps are equivalent to the classical ulnar nerve fascicle transfer, in terms of elbow flexion strength and donor nerve morbidity. Twenty‐five consecutive patients were operated between March 2007 and July 2013. The patients were divided into two groups. In Group 1 (n = 8), the patients received an ulnar nerve fascicle transfer to the biceps motor branch. In Group 2 (n = 15), the patients received a median nerve fascicle transfer to the biceps motor branch. Two patients with follow‐up less than six months were excluded. Both groups were similar regarding age (P = 0.070), interval of injury (P = 0.185), and follow‐up period (P = 0.477). Elbow flexion against gravity was achieved in 7 of 8 (87.5%) patients in Group 1, versus 14 of 15 (93.3%) patients in Group 2 (P = 1.000). The level of injury (C5‐C6 or C5‐C7) did not affect anti‐gravity elbow flexion recovery in both the groups (P = 1.000). It was concluded that the median nerve fascicle transfer to the biceps is as good as the ulnar nerve fascicle transfer, even in C5‐C7 injuries.

Efeito do Plasma Rico em Plaquetas na apoptose pós-traumática de condrócitos

OBJECTIVE: To evaluate if the injection of intra-articular platelet-rich plasma (PRP) can reduce impact-induced chondrocyte apoptosis. METHODS: A double-blind experimental study was developed in four knees of two adult rabbits. Each knee was injured after anesthesia. Subsequently, 1ml PRP was injected in the right knees and 1ml of normal saline (NS) in the left knees. The animals were euthanized ten days after the intervention. All cartilage was removed from the 4 knees and prepared for analysis in electron microscopy (EM). RESULTS: Four EM samples were obtained. The PRP-injected knees showed apoptosis rates of 47,62% (50/105) and 48,36% (59/122), respectively. NS-injected knees showed 56.67% (17/30) and 70.40% (88/125) of apoptosis. PRP-injected knees had statistically significant less apoptosis (48.02%) than NS-injected ones, (67.74%, p<0,001) and odds ratio of 0.439 (95% CI=0.287-0.673). CONCLUSION: Immediately post-traumatic intra-articular injection of PRP reduces impact-induced chondrocyte apoptosis in rabbits.

Comparative study of skin folding of dominant and nondominant hemibodies in spastic hemiplegic cerebral palsy

OBJECTIVE To compare skin folds in the dominant and nondominant halves of the body in a group (A) of 20 individuals with cerebral palsy and spastic hemiplegia and a group (B) of 30 normal volunteers. METHOD Body mass, height and skin folds were measured, and the percentage of body fat was estimated by adipose tissue measurement and densitometry. The mean age in group (A) was 24.6 ± 5.6 years (ranging from 16.1 to 38.1 years). The mean age in group (B) was 25.3 ± 3.8 years (ranging from 19.0 to 34.11 years). RESULTS Statistically significant differences were observed between the dominant and nondominant halves of the body for biceps, triceps, thoracic, suprailiac, thigh and midcalf skin folds in group A; the biceps, subscapular, midaxillary, suprailiac, abdominal, thigh and midcalf skin folds in group B; and the percentage fat obtained by adipose tissue measurement in both groups. Statistically significant differences were observed for the triceps skin fold when the dominant halves of the body in groups A and B were compared. Statistically significant differences were also observed for the biceps, triceps, thigh and midcalf skin folds as well as the adipose tissue measurements between the dominant and nondominant halves of the body in the two groups. The percentage fat as estimated by densitometry was significantly correlated with the adipose tissue measurement. CONCLUSION There were statistically significant differences between the skin folds in the dominant and nondominant halves of the body, both in group A and in group B (greater in group A). There was a statistically significant correlation in the percentage fat as estimated by densitometry and as measured by adipose tissue in groups A and B.

Effect of intertrochanteric osteotomy on the proximal femur of rabbits: assessment with power Doppler sonography and scintigraphy

OBJECTIVE In bone injury, repair results in local increased vascularity and bone marrow remodeling. Characterizing the vascular and metabolic imaging patterns of the proximal femur following an intertrochanteric osteotomy may help clinicians decide proper management of the patient. Our objective was to measure Doppler sonography and scintigraphy interval changes in the proximal femur following intertrochanteric osteotomy and compare imaging and histomorphometric measurements in the late post-operative stage (6 weeks after surgery) in a rabbit model of bone injury. MATERIALS AND METHODS Both hips of 12 adult rabbits were imaged with power Doppler sonography and scintigraphy prior to and after (7 days and 6 weeks) unilateral osteotomy. Accuracy of the imaging methods was evaluated using hip operative status and histomorphometric results (vascular fractional area and number of vessels per area unit) as reference standard measures. RESULTS A significant difference in the mean number of pixels was noted between operated and non-operated femura in late post-operative power Doppler examinations (P=0.049). Although without reaching statistical significance, the AUC of Doppler measurements (AUC=0.99) was numerically greater than the AUC of scintigraphy measurements (AUC=0.857+/-0.099) (P=0.15) in differentiating proximal femura with regard to their fractional vascular areas in the late post-operative stage. In contrast, scintigraphy tended to perform better (AUC=0.984+/-0.022) than Doppler ultrasound (AUC=0.746+/-0.131) to demonstrate the vascularity intensity per area unit (P=0.07) in the late stage. CONCLUSION Our results warrant further investigation to determine the value of different imaging modalities for assessment of pathologic changes following hip surgery. Power Doppler sonography demonstrated larger AUCs (representing higher accuracy) for the discrimination of vascular fractional areas and scintigraphy, for discrimination of the number of vessels per area unit.

Análise comparativa da resistência de fêmures de cães após a confecção de janelas ósseas circular e quadrada

With the purpose of evaluating the weakness caused by holes in the cortical bone, the authors performed circular holes in the diaphysis cortical bone of eight femurs from dog carcasses, and square holes in the diaphysis cortical bone of the contralateral femurs, the diagonals being similar to the diameters. The specimens were submitted to torsion stress test in a mechanical test machine to determine maximum torque and rigidity to torsion. Maximum mean torque for the femurs with circular holes was 13.65 ± 5.12 Nm and mean rigidity was 1.18 ± 0.45 Nm/degree, while the femurs with square holes showed maximum mean torque of 13.39 ± 5.23 Nm and mean rigidity of 1.05 ± 0.41 Nm/degree. The resistance to torsion stress in femurs with circular or square holes was very similar and the statistical analysis did not show a significant difference (p = 0.05).