Biomedical subjects

H L Defino

Publications and source records attributed to H L Defino.

6 recordsLinked to original sources

PubMed2001

Role of cortical and cancellous bone of the vertebral pedicle in implant fixation.

An experimental study was conducted to determine the role of cancellous and cortical bone of vertebral pedicles in the fixation of pedicular screws. Ten segments of the lumbar spinal column removed from adults at autopsy were used. Direct measurements were made to obtain the total diameter of the pedicles from L1 to L5 plus the diameter of cancellous bone and the diameter of cortical bone. For the study, the vertebra fragments were divided into two groups, each consisting of five sets of lumbar spine segments. In the first group, the pedicle was perforated using the orientation points employed in surgical procedures (articular facet and transverse process). In the second group, a transverse cut was made in the middle portion of the pedicle so that perforation and introduction of the screws could be performed under direct view. After pedicle perforation using a 3-mm drill, the screws were introduced into the vertebral pedicle in increasing order of diameter size, until structural alteration of the pedicle was observed (plastic deformation or rupture). These parameters were evaluated by means of successive measurements with a pachymeter and by direct observation. The screws used ranged in diameter from 3 to 12.5 mm, with progressive 0.5-mm increments. The analysis of the alterations in pedicle structure was performed by considering total diameter, spongy bone diameter, cortical bone diameter, and diameter of the screw used to produce the structural alteration. The results showed that the screws in general presented fixation mainly in the cancellous bone portion of the vertebral pedicle, whereas a small percentage of cortical bone was used for fixation.

Aged↗

PubMed2000

Induction of Fos protein immunoreactivity by spinal cord contusion.

The objective of the present study was to identify neurons in the central nervous system that respond to spinal contusion injury in the rat by monitoring the expression of the nuclear protein encoded by the c-fos gene, an activity-dependent gene, in spinal cord and brainstem regions. Rats were anesthetized with urethane and the injury was produced by dropping a 5-g weight from 20.0 cm onto the exposed dura at the T10-L1 vertebral level (contusion group). The spinal cord was exposed but not lesioned in anesthetized control animals (laminectomy group); intact animals were also subjected to anesthesia (intact control). Behavioral alterations were analyzed by Tarlov/Bohlman scores, 2 h after the procedures and the animals were then perfused for immunocytochemistry. The patterns of Fos-like immunoreactivity (FLI) which were site-specific, reproducible and correlated with spinal laminae that respond predominantly to noxious stimulation or injury: laminae I-II (outer substantia gelatinosa) and X and the nucleus of the intermediolateral cell column. At the brain stem level FLI was detected in the reticular formation, area postrema and solitary tract nucleus of lesioned animals. No Fos staining was detected by immunocytochemistry in the intact control group. However, detection of FLI in the group submitted to anesthesia and surgical procedures, although less intense than in the lesion group, indicated that microtraumas may occur which are not detected by the Tarlov/Bohlman scores. There is both a local and remote effect of a distal contusion on the spinal cord of rats, implicating sensory neurons and centers related to autonomic control in the reaction to this kind of injury.

Animals↗

PubMed1999

Reconstruction of anterior iliac crest bone graft donor sites: presentation of a surgical technique.

This study is a prospective evaluation of the reconstruction of anterior iliac crest bone graft donor sites using a technique developed by the authors. We present the technique and the initial results obtained with its use in 15 patients followed up for a period ranging from 6 to 16 months. Reconstruction of the iliac crest is performed using a rib, which is removed by an anterior approach to the spine. The rib is divided into two segments, which are fitted into the defect created in the iliac crest after removal of the bone graft. Clinical evaluation of the patients found a good cosmetic appearance of the reconstruction site, and the rib segments used showed good radiologic integration. Partial resorption of the segments was observed in two patients, with no effects on the cosmetic result.

Adult↗

PubMed1998

Treatment of fractures of the thoracolumbar spine by combined anteroposterior fixation using the Harms method.

Forty-three patients with fractures of the thoracolumbar spine submitted to surgical treatment using the Harms method (dorsoventral operations) were studied prospectively with a follow-up of at least 12 months and evaluated on the basis of clinical and radiologic parameters and in relation to their professional activities. Thirty-five patients (81.3%) were males and eight (18.7%) females, ranging in age from 17 to 67 years (mean 34.08+/-11.51 years). Seven patients (16.2%) presented fractures of more than one vertebra, and associated lesions were present in 15 patients (34.8%). Monosegmental fixation was performed in 7 patients (16.3%), bisegmental fixation in 29 (67.4%), and trisegmental fixation in 7 (16.3%). No patient was submitted to any type of external immobilization during the postoperative period and all patients were allowed to sit up in bed and to walk as soon as their clinical conditions permitted. Thirty-nine patients were followed up for a period ranging from 12 to 36 months (mean 16.58+/-6.83 months). Four patients died during the postoperative period (three of pulmonary embolism and one of septicemia). Forty-two patients sat up in bed between the 2nd and 6th postoperative day, and those who did not present a disabling lesion (Frankel D or E) or other associated lesions walked between the 4th and 10th postoperative day (mean 6.14+/-6.06 days). The neurological signs and symptoms improved in 16 patients (37.3%), were unchanged in 26 (60.4%), and worsened in 1 (2.3%). Twenty-three patients (87.5%) who had no neurological damage (Frankel E) returned to their professional activities after respective periods of disability of 1 month (three patients), 2 months (four patients), 3 months (one patient), 4 months (seven patients), 5-7 months (five patients), 8-12 months (one patient), and more than 12 months (three patients). The ability to work of the 24 patients without neurological damage was 100% in 21, 50% in 2, and zero in 1. The ability to walk of this group of patients was 1-5 km for 4 and more than 5 km for the remaining 20 patients. The complications observed were death (four patients; three cases of pulmonary embolism and one case of septicemia), infection (two patients), Stevens-Johnson syndrome (one patient), and meningitis (one patient). The mean kyphosis of the fractured segment was 22.17 degrees +/- 10.97 degrees preoperatively, 8.55 degrees +/- 6.9 degrees postoperatively, and 10.30 degrees +/- 8.84 degrees on the occasion of late evaluation. No loss of correction occurred in 28 patients (71.8%), a 5 degrees loss was observed in 3 patients (7.6%), a 6 degrees loss in 3 (7.6%), a 7 degrees loss in 3 (7.6%), and a loss of more than 10 degrees in 2 (5.2%).

Adult↗

PubMed1996

Spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL): a Brazilian case.

This is a report on a Brazilian patient with spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL; MIM 271640), a rare autosomal recessive skeletal dysplasia characterized by dwarfism, articular hypermobility, progressive intractable spinal malalignment, a typical facies and a propensity to joint dislocation and subluxation. The condition has been described only in 20 children of Afrikaans-speaking parents in South Africa. This is the first report of a non-Afrikaans patient with this genetic entity.

Brazil↗

PubMed1986

Studies on tendon healing. A comparison between suturing techniques.

An experimental study comparing Kessler's and Tsuge's techniques for tendon suture was undertaken in dogs. Both second and fifth flexor digitorum profundi tendons of the left forepaw were divided in the segment corresponding to zone 2 of human hands. Following division, the tendons to the second digit were repaired by Kessler's technique and those to the fifth digit by Tsuge's method. Results were evaluated by means of standard and polarized--light microscopy, intravascular dye injections and tensile strength tests. Both ordinary and polarized--light microscopy showed that a microscopical gap develops between the tendon ends, being filled in with healing tissue which undergoes progressive maturation. The tensile strength tests showed that the deformation (elongation) progress directly with load, up to the point of rupture; the suture thread does not interfere with this. Furthermore, strength increases with time. Intravascular dye injection showed that a net of newly formed blood vessels develops at the site of section and suture, previously destitute of macroscopical vessels. The new vessels tended to redistribute them selves to resemble the pattern in normally vascularized regions. It was not possible to detect, by means of the methods employed, any important difference between Kessler's and Tsuge's techniques for tendon suture.

Animals↗