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Biomedical subjects

N Passuti

Publications and source records attributed to N Passuti.

81 records · Page 5Linked to original sources
PubMed1984

[5-year results of Salter's osteotomy in the treatment of congenital hip dislocation. Apropos of 30 cases].

Residual dysplasia and iatrogenic osteochondritis are two complications of treatment of congenital dislocation of the hip. Confidence is placed in the use of slow orthopedic reduction with a combined stabilizing Salter's osteotomy. This method was applied in 20 cases while in 10 patients a Salter's operation was performed for confirmed failure of orthopedic therapy. These were cases of severe dislocation, the mean age of the patients when starting treatment being 11 months. The mean age at the last follow-up examination was 5 years, when confirmation was obtained of the excellent clinical result, and particularly the radiographic outcome with normal cotyloid angles and good anterior cover. Pelvic osteotomy when mean age was 22 months produced as near as possible a normal hip before 6 years of age, without altering growth of the surperior extremity of the femur.

Age Factors↗
PubMedDate not supplied

Spinal or systemic analgesia after extensive spinal surgery: comparison between intrathecal morphine and intravenous fentanyl plus clonidine.

STUDY OBJECTIVE: To compare two different methods of postoperative analgesia after extensive spinal fusion. DESIGN: Double-blind, randomized study. SETTING: University-affiliated hospital. PATIENTS: Twenty four adult patients undergoing scoliosis correction. INTERVENTIONS: Before the end of surgery, patients received either intravenous clonidine 0.3 micrograms/kg/hr and fentanyl 25 micrograms/kg (after an hourly dose of clonidine 2.5 micrograms/kg) or intrathecal morphine 0.3 mg. A saline infusion was administered to patients receiving morphine intrathecally. MEASUREMENTS AND MAIN RESULTS: Pain and sedation scores, hemodynamic data, and blood gases were collected in the recovery room at tracheal extubation and then every 2 hours for the next 14 hours. Tracheal extubation was performed at the same time in both groups (i.e., an average of 4 hours after the analgesic regimens were started). Intrathecal morphine provided a mean score of 20 mm on a visual analog scale ranging from 0 mm (no pain) to 100 mm (severe pain), but it resulted in increased PaCO2 at extubation (44 +/- 7 mmHg) and 2 hours later (42 +/- 7 mmHg). PaCO2 was greater than 50 mmHg in four patients receiving intrathecal morphine. Fentanyl-clonidine resulted in equipotent analgesia but was accompanied by sedation (sleeping but arousal by light tactile stimulation) and moderate hypotension (up to 69 +/- 9 mmHg for mean arterial pressure). CONCLUSIONS: This study shows that there is a major risk of respiratory depression with a single intrathecal dose of morphine 0.3 mg to control postoperative pain after scoliosis surgery. Systemic clonidine-fentanyl may be a possible approach to the postoperative pain treatment of this surgery.

Adult↗
PubMedDate not supplied

[Calcium phosphate ceramics in orthopedic surgery].

Calcium phosphate ceramics might replace bone grafts in orthopaedic surgery. The chemical determination of these materials is now well known, and world-wide animal experiments as well as our own experience have proven that these products are both biocompatible and bioactive. The early chemical and physico-chemical mechanisms of interaction between calcium phosphate ceramics and bone tissue and biological fluids at the site of implantation are numerous (degradation, dissolution, crystal precipitation). These processes precede the cellular mechanisms of osteogenesis which take place during contact with the materials and define osteoconduction. When implanted in a bony environment, the ceramic ensures the formation of a genuine bone which within a few months will acquire all the characteristics of a normal lamellated bone with areas of apposition and resorption during remodeling. However, the mechanical characteristics of calcium phosphate ceramics do not permit an early loading, and they should only be used to fill bone cavities. In vertebral arthrodesis they must be implanted in stress-free areas and combined with strong and stable appliances. To benefit from the special bioactivity of calcium phosphate ceramics, research workers are now turning towards the treatment of metal alloys or composite fibres surfaces as well as of calcium phosphate complexes and extracellular matrix constituents (collagen, proteoglycans, etc.).

Biocompatible Materials↗
PubMedDate not supplied

[Bone resection-reconstruction of the diaphyseal zone in animals. Development of an experimental model, application to the study of biomaterials compared with allografts].

The aim of this work was to develop an animal model of bony resection-reconstruction of the diaphyseal zone and to test the different bone substitutes in comparison with allografts. Eighteen 2-cm diaphyseal resections of the femur were performed in Beagle dogs. Reconstruction was performed using a bone substitute (5 cryopreserved allografts, 5 blocks of polymethylmetracylate with PMH hydroxyapatite, 8 blocks of phosphocalcium ceramic materials with biphased macropores) associated with centromedullar lockek nail. The PMH blocks gave radiographically and histologically unsatisfactory results. Allografts consolidated in two-thirds of the junctions, consolidating with an exuberant periosteal callus contrasting with minimal intracortical repair. No stress fractures were observed despite normal activity. BCP blocks consolidated in three-fourths of the junctions but pseudoarthrosis at the centre of the block was observed in cases in which the fixation was not perfectly stable. Bone occupied 20 and 24% of the surface of the ceramic block in the central and junctional zones respectively. These findings demonstrated the reliability of internal fixation material in the animal model and allowed us to evaluate the different methods for analysing bone repair on histographic and microradiographic images. In addition, the potential of synthetic material such as MBC might be useful in large resections in mechanically stressed zones.

Animals↗
PubMedDate not supplied

[The sheep: an animal model for ligament prostheses?].

Ruptures of the anterior cruciform ligament is difficult to repair. Ligament prostheses are sometimes useful. We tested a ligament prosthesis which had the original property of combining a polyester braid with a matrix favouring collagen ingrowth. We implanted this prosthesis in the knee joint of 10 sheep after sectioning the anterior cruciform ligament at it origin. The ligaments were recovered after 6 months. We studied the functional and radiographic results. Tolerance was studied in samples of the articular fluid and synovial tissue. We evaluated bone attachment and fibrous growth using micro-radiography and specific coloration techniques. Samples were examined under electron microscope. No rupture was encountered. We observed a satisfactory functional and radiographic result. No intolerance was observed. The neoligament had a bony or mixed attachment in 60% of the cases and was comprised of oriented tissue in 90% of the cases. Vascular invasion was important. These findings are promising and suggest that long-term studies should be undertaken.

Animals↗
PubMedDate not supplied

[Multi-level traumatic lesions of the thoracic and lumbar spine. Value of the Cotrel-Dubousset instrumentation].

Trauma of the spine involving several thoracic and lumbar vertebrae is rare (4 case in 250 spine operated in our unit from 1985 to 1990) and require difficult therapeutic decisions. The patients has one or more unstable fractures which could require 4 screw-plates that would be mechanically unsatisfactory, or an unstable fracture combined with other stable lesions requiring a mixed orthopaedic and surgical treatment that would lead to long term decubitus with a corset. The Cotrel-Dubousset system makes it possible to approach each lesion separately with segmentary instrumentation. Using different combinations of the implants we were able to obtain a construction which was both technically and mechanically satisfactory and allowed recovery of the sagittal spinal curvatures without external contention. A single operation treating all the different lesions was sufficient in 3 Frankel E patients, allowing them to return to their former activities in 3 to 6 months. The material was removed at about 20 months allowing good spinal mobility.

Adolescent↗