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Biomedical subjects

D G Marchesi

Publications and source records attributed to D G Marchesi.

11 recordsLinked to original sources
PubMed2000

Spinal fusions: bone and bone substitutes.

Vertebral arthrodesis is one of the most commonly performed, yet incompletely understood, procedures in spinal surgery. Despite major progress in internal fixation techniques, the high rate of nonunions indicates that physiologic, biologic and molecular events that are crucial to this process are not well known. This article will analyze the general biology of bone regeneration, and particularly discuss the properties and use of various bone graft materials and graft substitutes.

Bone Regeneration↗
PubMed1997

Management of odontoid fractures.

During the past two decades, various reports on the management of odontoid and axis body fractures have been published and new methods of treatment have been developed. So far, there is no consensus, and management remains controversial. This article reviews the literature and formulates recommendations based on clinical experience.

Adult↗
PubMed1993

Anterior transpedicular fixation of the lower thoracic and lumbar spine. Experimental verification using a new direction finder.

Currently, no anterior spinal implant provides a strong bone-screw interface because of the cancellous characteristics of the vertebral body. A more secure anchorage could be obtained by anterior transpedicular screw fixation. Four hundred transpedicular screws located between T7 and L5 were placed using the newly developed direction finder. Measurements were obtained directly from radiographs of the cadaveric specimens. In 10 cases (2.5%), the screws crossed the medial pedicle border, but never by more than 1.4 mm. A lateral protrusion was noted in another 41 screws (10%), with no protrusion greater than 2.2 mm. Encroachments beyond the superior or inferior border were not observed. The mean angle of the screws at each level measured between 7 and 19 in the transverse plane and between 2 and 4.5 in the sagittal plane. This technique should be reserved for vertebrae without significant arthritic changes. The rare screw with minimal infraction through the medial or lateral pedicle wall should not cause any vascular or neural compromise. The anterior transpedicular screw technique appeared relatively safe (88%) and encouraged the development of the new plate system for anterior spinal stabilization.

Adult↗
PubMed1993

Surgical treatment of tumors of the cervical spine and first two thoracic vertebrae.

From 1985 through 1990, 19 patients with tumorous conditions of the cervical spine and the first two thoracic vertebrae were treated with anterior, posterior, or combined anterior/posterior surgical techniques. Breast metastases were by far the most common condition (42%). Patients usually experienced severe pain, which resisted conservative treatment, sometimes associated with radiculopathies (42%) or neurological deficits (31%). To date, the treatment of spinal tumors is only palliative, and surgery must be considered for cases with unremitting neck pain, major vertebral destruction with loss, or impending loss of cervical spine stability and neurological deficits due to local tumor compression. Contrary to the commonly used posterior wiring stabilizations, we preferred stabilization techniques more closed to those used in traumatology. Our findings suggest anterior surgery alone with vertebrectomy and stabilization with plate and bone cement for tumors involving only one vertebra and localized between C3 and T1. Posterior approach and stabilization is advocated for atlantoaxial lesions. A combined anterior and posterior technique should be reserved for extended tumoral conditions where an anterior fixation does not offer enough stability or where more radical surgery is required. In the present series, immediate good spinal stabilization and neck pain relief was obtained in every case, allowing early mobilization. Improvement of the neurologic deficit was noted in 65% of our patients.

Adult↗
PubMed1992

Alignment of supracondylar/intercondylar fractures of the femur after internal fixation by AO/ASIF technique.

Fifty-nine supracondylar-intercondylar fractures of the femur in 57 patients were evaluated after a mean follow-up of 5 years 7 months (range 2 years to 11 years 3 months) after internal fixation using AO/ASIF technique. Axial alignment was compared with that of the uninjured side by orthoroentgenography in the upright position and by bilateral anteroposterior (AP) and lateral views of the femur. Identical values for varus/valgus were noted in 24%, for ante/recurvation in 72%, and for rotation in 61%; differences were within 5 degrees of varus/valgus in 74%, of ante/recurvation in 78%, and of rotation in 83%. Alignment differences were more frequent in complicated and intercondylar fractures according to the AO classification of fractures. We conclude that restoration of the distal femoral angle is far more difficult than restoration of the sagittal plane and rotation, but a satisfactory functional result appears to be compatible with angulation differences of less than or equal to 5 degrees in any plane and that this difference appears to be within the reasonably achievable limits. 93% of the patients were satisfied; 64% of patients were pain-free, and 27% had slight intermittent pain (not interfering with daily activity); 67% of the patients had unlimited walking distance, and 78% of the patients were able to walk without aid. Excellent and good results according to the rating systems of Neer et al., Pritchett, and Schatzker and Lambert were noted in 82, 39, and 26%, respectively. This discrepancy between alignment, pain, function, and results according to different rating systems underlines the need for future standardized, clearly defined reporting and classification of rating.

Adolescent↗
PubMed1992

Changes in vertebral rotation after Harrington and Luque instrumentation for idiopathic scoliosis.

This study was carried out to analyze the three-dimensional and in particular the rotational correction obtained after spine instrumentation for idiopathic scoliosis. Preoperative and postoperative radiographs and computed tomographic scans with single axial cuts through each vertebral level were obtained for 14 patients: 4 Harrington, 7 Luque, and 3 Harrington-Luque. Rotation of vertebrae relative to the spinal axis and rotation between vertebrae (segmental rotation) were measured from computed tomographic scans of instrumented and uninstrumented segments. The derotation and changes occurring after surgery were calculated. Before operation, rotation was maximal at the apex, and close to 0 at the end vertebra; segmental rotation was greatest at the end of the curve, and minimal at the apex. After Harrington instrumentation the apical vertebrae showed a median derotation of 16%, after Luque instrumentation it was 12% and after Harrington-Luque instrumentation it was 13%. Segmental derotation did not uniformly occur. Major derotation was obtained at the end vertebrae and 39% of the total derotation occurred outside of the instrumented levels of the spine.

Adult↗
PubMed1992

Pedicle fixation devices in the treatment of adult lumbar scoliosis.

Segmental pedicle screw instrumentation in adult lumbar scoliosis allows better curve correction and restoration of lumbar lordosis. In a retrospective study, to assess the value of this fixation, 9 patients treated with the AO Internal Fixator and 18 with Cotrel-Dubousset instrumentation were reviewed. Mean age at surgery was 60 years (range, 40-88), and curves were measured between 22 degrees and 82 degrees. At follow-up (mean of 56 months for the AO Internal Fixator and 42 months for Cotrel-Dubousset instrumentation), the average curve correction was better than 50% Overall satisfactory clinical results with pain relief and improved walking distance were noted in 86% of the patients. Using this technique no postoperative deaths or neurologic deficits occurred. Only a few complications and a 4% pseudarthrosis rate could be observed. Our study shows that the age of the patients with degenerative scoliosis is not a contraindication for major surgery. Meticulous posterior spine release before instrumentation is essential for curve correction and bone fusion. Lumbar lordosis is more easily restored with Cotrel-Dubousset instrumentation, which seems to correspond to the incidence of low back pain. Cases with evident neurologic deficits are best treated by additional nerve decompression.

Adult↗
PubMed1991

Application and results of the AO internal fixation system in nontraumatic indications.

The AO internal skeletal fixation system (ISFS) permits posterior spine fixation to be restricted to the vertebrae immediately adjacent to the lesion and allows manipulation of each instrumented vertebra in three planes. In a prospective study to assess the value of this fixation for adult spinal disorders, 68 patients were reviewed. The device was used in spondylolisthesis, postlaminectomy instability, post-traumatic kyphosis, degenerative scoliosis, spinal stenosis, tumors, and infections. A total of 322 transpedicular screws have been inserted without neurologic complication. Satisfactory results were achieved in 88% of the patients, and only four pseudarthroses (6%) occurred. The ISFS provides rigid stabilization to enhance bone graft consolidation and to allow rapid postoperative mobilization in a light external orthosis.

Bone Screws↗
PubMed1991

[Arthritis following osteosynthesis of supra-/intercondylar femoral fractures].

Of 104 supra-/intercondylar femur fractures in adults (AO/ASIF Classification types A 1-3 and C 1-3), who were treated by open reduction and internal fixation from 1975 to 1985 59 fractures in 57 patients could be traced and reviewed clinically and radiographically after a mean follow-up period of 5 years and 7 months (range: 2-11 years). Among these, 47 knees/patients without preexisting knee-joint pathology were analyzed for the development of degenerative arthritis. The incidence for grade 2 and 3 changes in the femoropatellar compartment were 23% for supracondylar fractures (A type) and 62% for intercondylar lesions (C type). In the femorotibial compartment the incidence for supracondylar fractures was 38% and 23% for intercondylar fractures. In 93% of the patients the arthritic changes were radiographical findings, which did not cause relevant symptoms. The development of radiographical degenerative changes depends mainly on the type of the fracture; it is favoured by axial malalignment of more than 5 degrees of varus or valgus and local complications.

Adolescent↗
PubMed1989

[Total prosthesis implantation with added pelvic osteosynthesis].

This report documents our limited experience with total hip replacement requiring large bone-graft reconstruction of the acetabulum with internal fixation. Four of the 14 patients were elderly and had a fresh fracture of the acetabulum; 6 had severe loosening of the acetabular companent with non-union, necessitating plate fixation along the pelvic rim in 5 patients. Four patients had large defects after tumor resection. In only 1 of these 14 cases did loosening occur. Our results are promising and we plan to increase the use of pelvic plates in these extremely unstable cases. Following stabilization of the pelvic ring, a metallic reinforcement ring increases stability. These operations were performed via an anterior ilioinguinal approach.

Acetabulum↗