PubMed Health⌕ Search

Biomedical subjects

P Lisai

Publications and source records attributed to P Lisai.

13 recordsLinked to original sources
PubMed1991

[Intradural herniated disk: report of 2 cases].

Taking advantage of the observation of 2 instances of intradural disk herniation, the authors examine the pathogenetic, clinical, diagnostic, and therapeutic aspects of this rare occurrence in light of a review of the literature and their own observations. Of the theories as to the cause of the syndrome, two appear worth noting: the relative immobility of the dural sac, bound by the surrounding nerve roots; the inflammatory and cicatricial adhesions that establish themselves between the posterior longitudinal ligament and the dural sac. The clinical features as well as the laboratory and diagnostic tests suggest compression of one or more nerve roots similar to that caused by other intradural expansion processes. The onset can be sudden and acute or delayed depending on whether the dural sac adhesions were present before disk herniation or appeared at a later stage. Intradural disk herniation must be checked for, often intraoperatively, in all cases of radiculopathy due to intradural compression. Error in the assessment of the level of the lesion, concomitant extruded extradural disk herniation, or failure to recognize the immobility of the dural sac can all lead to misdiagnosis of intradural disk herniation if the search for this syndrome is not correctly carried out.

Adult↗
PubMed1991

[The action of loads on bone tissue].

This paper analyses the effect of mechanical loading on bone remodelling under both physiological and pathological conditions. The sensitivity and the type of the biological response of bone to the changes in mechanical loading are conditioned by several factors: individual race and age, pattern of stress, systemic and local metabolic conditions, etc. Therefore, bone remodelling following mechanical stress is not only a simple repair process, but a complex mechanism of functional adaptation which is controlled by the strain magnitude of bone structure rather than the extent of the stress. Results show that the skeletal changes induced by mechanical stress involve not only the structural properties but also the material characteristics of bone. For example, the size of hydroxyapatite crystals increases under load. These findings allow us to hypothesize that mechanical stress could directly modify the mineral component of bone. Hydroxyapatite appears to be a highly dynamic structure, able to change its crystallinity in relation to external stimuli. It is thus conceivable that hydroxyapatite crystals gather and arient themselves along bone and improve their crystallinity not only under the influence of biological mechanisms, but also as a reaction to mechanical stimuli.

Biomechanical Phenomena↗
PubMed1990

[Chordoma (a review of 11 cases)].

Eleven cases of chordoma, localized at sacrum (3 cases), lumbar spine (6 cases), cervical spine (2 cases), are reported. Authors describe clinical and pathological findings of the tumor and underline peculiarity of spinal localization and difficulty of diagnosis, often delayed, particularly in sacral spine localizations. Radiotherapy and chemotherapy give poor results while surgery can be employed in the treatment on account of the slow evolution and of the not very frequent aptitude of the tumor to give metastases. However peculiar localization into the sacral spine allows to remove the whole tumor if only it is localized below the 2nd sacral vertebra; authors present such a case treated by means of subtotal resection of sacrum and coccyx. In proximal sacral localizations and in other spinal localizations, surgery is a palliative procedure and can only slow down the evolution of the tumor; recurrence is a rule, even in association with radiotherapy. However surgical treatment must be often performed because of myeloradicular involvement.

Cervical Vertebrae↗
PubMed1990

[The modality of endoconnective ossification on cartilaginous substrate: observations on the long bones in the embryo].

The authors conducted a histologic study on the modalities of ossification of the "diaphyseal osseous ferrule" in embryos between the sixth and eighth week of intrauterine life: the ossification of this "diaphyseal osseous ferrule" presents some peculiarities compared to that of other areas: it occurs with the modalities of periosteal ossification, exploiting, however, a cartilagenous substrate. In addition, the authors compared the ossification of the diaphyseal ferrule to that of the "perichondrial ferrule of the layer of ossification", examining histologic sections of embryos in the 25th week of intrauterine life.

Cartilage↗
PubMed1990

[Perichondrial changes in the evolutionary course of traumatic lesions of the epiphysis in growth].

The authors conducted an experimental study aimed at defining the response of the perichondrium to traumatic stimuli. Thirty rabbits were used, subdivided into two groups: in the first group, the perichondrium was submitted to indirect trauma (fracture of the growth nucleus); in the other, to direct trauma (decortication of th perichondrium). We observed that the lesions constitute a stimulus for cellular proliferation with successive differentiation depending on various procedures. The mesenchymal cells of the deeper layer of the perichondrium reveal a tendency towards differentiation in a chondroblastic sense; the portion of these cells which face the metaphysis are generally differentiated to constitute typical cytotypes of the periosteum, giving way to membranous ossification phenomena. The more external layer reveals proliferation of its fibrovascular component. This experimental model allowed us to emphasise the proliferative tendency of so-called perichondrial cells (those of the deep layer). Thus, their role in providing the growth cartilage of new chondrocytes was confirmed, contributing to the transverse development of the metaphysis.

Animals↗
PubMed1990

[The role of osteotomy in the therapy of the arthritic genu varum].

The good results achieved with osteotomy in the treatment of arthritic varus knee lead the authors to pinpoint some frequently controversial aspects that are important for the attainment of an excellent outcome. The study consisted of 46 patients, each subjected to valgus osteotomy. The site of the tibial osteotomy should be above the insertion point of the patellar tendon in order to better guarantee stability and healing. For mechanical reasons, high metaphyseal peroneal osteotomy is preferred over other methods such as diaphyseal osteotomy, excision of the peroneal head, and proximal tibioperoneal syndesmotomy. Both osteotomies can be done through a single anterolateral incision, without risking injury to the lateral popliteal sciatic nerve. The preferred method of osteotomy is to cut a noncuneiform linear rima with the osteotome and perform the angular correction at the joint of the metaphyseal spongy bone. The osteotomy is then stabilized with staples and a cast for a period of 40 days. Overcorrection past the physiological valgus deformity is necessary in order to move the weight-bearing axis onto the lateral hemirima; the degree of surgical correction should be calculated on the basis of orthostatic radiographs. Good clinical results are always accompanied by the following radiographic developments: opening of the medial articular hemirima, improvement of the subchondral bone sclerosis, and reappearance of the outlines of both the spongy bone and the subchondral bone lamina; all these are signs of good bone adjustment made possible by the reinstatement of mechanical equilibrium in the knee.

Arthritis↗
PubMed1990

[Percutaneous nucleotomy: the indications and limits].

The authors report the results of automated percutaneous diskectomy in the treatment of the herniated disk. During an 18-month period this procedure was used on 39 patients with both evident radicular pathology that had not regressed even after 4-6 weeks of medical and physical therapy as well as clear disk herniation revealed by diagnostic imaging. The level of the herniated disk was L4-L5 in 30 cases. L5-S1 in 7 cases, and L3-L4 in 2 cases. The clinical diagnosis was confirmed by CAT scan in 20 cases, by both CAT scan and x-ray of the spinal region in 14 cases, and by x-ray only in 5 cases. The patients were reviewed 2, 6, and 12 months after surgery. The results were classified according to Watters' criteria based on both the relief of pain and the resumption of everyday work activity. The satisfactory results (excellent and good) totaled 59% at the 6-month follow-up, with no substantial variation at the 1-year follow-up. Hemilaminectomy was performed in 12 cases with unsatisfactory results, confirming the diagnosis of disk herniation in 10 cases (extruded in 9 cases and protruded in 1 case). Diskectomy is a non-invasive, atraumatic method which is indicated for both protruded (non-sequestrated) and subumbilical hernias and allows rapid functional recovery. The rate of success can be increased with more accurate selection of patients based on imaging diagnosis (CAT scan and MRI).

Adolescent↗
PubMed1989

[Diagnostic problems in Ewing's sarcoma].

Ewing's sarcoma presents diagnostic problems with several inflammatory processes (osteomyelitis, osteoperiostitis, eosinophilic granuloma) and other bone tumors. Clinical, radiographic and laboratory findings must be supported by a careful biopsy. Delimitation of reticulosarcoma and metastatic neuroblastoma is also extremely difficult from a histopathological point of view.

Adolescent↗
PubMed1989

[Reticulosarcoma: diagnostic problems].

Diagnostic problems connected with reticulum cell sarcoma are analyzed. Clinical, radiological, biochemical and hematological investigations combined with an accurate pathologic study are essential in order to arrive at a precise diagnosis. Ewing's sarcoma and other osteolytic sarcomas are discussed in the differential diagnosis.

Adolescent↗
PubMed1989

Soft tissue trauma: a randomised controlled trial of the topical application of felbinac, a new NSAID.

Two hundred and thirty-one patients with acute soft tissue injuries were treated in a double-blind placebo-controlled study of felbinac (biphenylacetic acid) gel applied three times daily to the injured site. Those treated with felbinac had significantly greater improvement at Day 4 (p less than 0.001) and Day 7 (p less than 0.02) than those who received placebo. Patients' self-assessment diary cards confirmed superiority of the active treatment as early as Day 2 of the study. Local skin reactions were few (three per cent), mild and recovered spontaneously. Felbinac is an effective management for acute soft tissue injuries and because of its topical application may be safer than oral non-steroidal anti-inflammatory drugs for the treatment of these conditions.

Administration, Topical↗
PubMed1988

Experimental investigation into reparative osteogenesis with fibrin adhesive.

An experimental investigation was carried out in order to evaluate the effects of fibrin adhesive on the reparative osteogenesis of bone grafts in the short, medium, and long term. Sixty fully developed New Zealand White rabbits under general anesthesia were grafted with homologous bone tissue in the proximal third of each tibias. Fibrin adhesive was used in one hind limb only. The animals were killed at a predetermined time. Both tibias were removed and subjected to radiographic and histologic analyses. The reparative process was observed and the differences between the fibrin adhesive-treated grafts and the reference group in the first few weeks were determined. No substantial difference was detected in the reparative osteogenetic process of the graft in the animals killed after 2 months.

Animals↗