Biomedical subjects

O Antonyshyn

Publications and source records attributed to O Antonyshyn.

28 records · Page 2Linked to original sources

PubMed1989

Blow-in fractures of the orbit.

A blow-in fracture is an inwardly displaced fracture of the orbital rim or wall resulting in decreased orbital volume. The purpose of this study is to classify orbital blow-in fractures, describe the distinguishing clinical and radiologic features, and review the result of treatment. The series consists of 41 patients with blow-in fractures (34 males and 7 females). The mean age of the patients was 36 years. All were treated between 1979 and December of 1986 at Sunnybrook Medical Centre in Toronto. Clinical features of blow-in fractures were primarily related to the decrease in volume of the orbital cavity. Proptosis was a consistent finding, and in 27 percent of patients, the globe was further displaced in a coronal plane. Restricted ocular motility and diplopia were documented in 24 and 32 percent of patients, respectively. Fracture fragments displaced into the orbit resulted in globe rupture in 12 percent of patients, superior orbital fissure syndrome in 10 percent, and optic nerve injury in 1 patient. Blow-in orbital injuries were classified as pure fractures, consisting of an isolated blow-in of a segment of the roof, floor, or walls, or impure fractures, where the orbital rim itself was disrupted. In all cases, early decompression of the orbit and open reduction of fractures was necessary. Late sequelae of blow-in fractures were primarily related to injuries of intraorbital contents. Twelve percent of patients underwent enucleation and 8 percent reported persistent diplopia. Despite the presence of superior orbital fissure syndrome and complete ophthalmoplegia in 10 percent of patients, early orbital decompression resulted in resolution of nerve palsies in all but one patient.

Adolescent↗

PubMed1989

Complex orbital fractures: a critical analysis of immediate bone graft reconstruction.

The present study reviews the long-term results of immediate reconstruction and primary grafting in 49 complex orbital fractures. The clinical features of these injuries are defined, and methods of investigation and surgical correction are outlined. The residual postoperative abnormalities, including enophthalmos, strabismus, and telecanthus, are critically analyzed. Recent modifications in fracture fixation, in orbital cavity reconstruction, and in the use of various types of autogenous grafts are discussed in detail.

Bone Transplantation↗

PubMed1988

Versatility of temporal muscle and fascial flaps.

The muscle and superficial fascia of the temporal area differ in their physical characteristics, vascular supply and clinical applications. Both can be employed independently or simultaneously as regional flaps in the reconstruction of a variety of complex craniofacial defects. The present paper reviews the anatomy, surgical technique and utilisation of temporal flaps.

Adult↗

PubMed1988

Complications of soft tissue expansion.

This paper presents a critical review of the results of tissue expansion in our clinical experience. Seventy-six expansions performed in 66 patients between 1981 and August 1986 are included in the study. Complications necessitating some revision in the original treatment plan were documented in 39% of cases. However, sufficient tissue was usually generated to complete the proposed reconstruction without compromising the final results. The complications of tissue expansion are further analysed in relation to their anatomical distribution, time of onset and ultimate consequences. Causative factors are identified and preventative measures are introduced.

Adolescent↗

PubMed1988

Tissue expansion in head and neck reconstruction.

The present study reviews our clinical experience with tissue expansion in head and neck reconstruction. The clinical series consists of 33 expansions performed in 29 patients between 1983 and 1986. The results of tissue expansion in the head and neck were distinguished by a high complication rate, necessitating some revision in the original treatment plan in 48 percent of patients. Despite this high incidence of complications, sufficient tissue was generated to successfully complete the planned reconstruction in 79 percent of patients. Specific complications were observed with particularly high frequency within distinct anatomic sites. The highest incidence of complications occurred in the cheek and neck (69 percent) and forehead (50 percent) regions. Complications in the eyelid region (33 percent) and scalp (17 percent) were less common. Implant exposure was the most frequently observed complication. Other sequelae noted in this series included intractable pain, infection, and bone resorption.

Adolescent↗

PubMed1987

Growth potential in suture bone inlay grafts: a comparison of vascularized and free calvarial bone grafts.

The present study investigates transsutural growth in vascularized and free calvarial bone grafts and notes the effects of such growth on craniofacial development. The temporalis myoosseous flap served as a model of vascularized graft. In ten 8-week-old dogs, a standardized skeletal defect, including a segment of the zygomatico-maxillary suture, was created. The defect was reconstructed with a vascularized graft in half the animals and a corresponding free graft in the remaining animals. Growth was assessed by means of serial cephalometric radiography and direct osteometry. Vascularized bone grafts demonstrated persistent transsutural growth following transplantation. Growth at the recipient site was preserved, resulting in less restriction of vertical maxillary development.

Animals↗

PubMed1987

Complex orbital trauma: the role of rigid fixation and primary bone grafting.

High-velocity trauma to the orbit is characterized by complete disruption of the orbital rim and comminution of the walls of the orbital cavity. The incidence of associated injury to the intraorbital contents, and to contiguous facial skeletal structures, is significant. Failure to recognize and repair the skeletal injuries results in progressive contracture of the overlying soft tissues, collapse of the bony framework of the orbit, and atrophy of incarcerated intraorbital contents. Immediate orbital reconstruction aims to restore and maintain the normal anatomy of the craniofacial skeleton. The introduction of computed tomography (CT) and craniofacial surgical techniques facilitates comprehensive evaluation of orbital fractures. Further adaptation of the principles and techniques of rigid internal skeletal fixation and primary bone grafting permits a stable, three-dimensional, anatomic reconstruction of virtually any traumatic orbital deformity.

Bone Plates↗

PubMed1987

Growth potential in onlay bone grafts: a comparison of vascularized and free calvarial bone and suture bone grafts.

Vascularized bone grafts are characterized by a viable cell population with osteogenic potential. These features suggest that continued growth can be anticipated following vascularized membranous bone transfer in a growing craniofacial skeleton. The present paper compares the potential for appositional bone growth in vascularized and free calvarial onlay bone grafts. In seven 8-week-old beagles, growth was assessed by direct caliper measurements of graft dimensions intraoperatively and 16 weeks postoperatively. Vascularized grafts demonstrated a 50 to 60 percent increase in size in all dimensions compared to 10 to 20 percent growth in free grafts (p less than 0.01). Microradiography revealed preservation of calvarial bony architecture and minimal resorption in vascularized grafts, while triple-fluorochrome labeling confirmed subperiosteal appositional bone formation. Free grafts were characterized by significant resorption and a delay in subperiosteal bone formation.

Animals↗

PubMed1987

The temporalis muscle flap for head and neck reconstruction.

The temporalis muscle receives its blood supply from the anterior and posterior deep temporal arteries. These run between the muscle and the periosteum and, therefore, subperiosteal elevation of this fan-shaped muscle from its origin in the temporal fossa results in a viable muscle flap whose arc of rotation and reach can be increased by resection of the zygomatic arch and the coronoid process of the mandible. The flap is useful in reconstruction of the mouth where it reaches at least to the ipsilateral lower canine tooth, the palate to the midline, the orbit and the ear. Skin grafts are readily accepted on its surface. The surgical technique is described in detail and the use of the flap in two representative cases is documented.

Aged↗

PubMed1986

The temporalis myo-osseous flap: an experimental study.

The present paper investigates the anatomy and vascularization of the temporalis myo-osseous flap. This is a calvarial bone flap that employs temporalis muscle and its distal pericranial extension as a pedicle. In six human cadavers the flap was raised as an island on the anterior deep temporal artery after transecting the zygomatic arch and coronoid process. Maximal mobilization was thus obtained, allowing rotation of the flap into the mouth for intraoral reconstruction. The arc of rotation and potential surgical applications were noted. A comparative study of the temporalis myo-osseous flap and free calvarial bone graft was then conducted in a rabbit model. Vascularization of the calvarial bone flap was confirmed by technetium scintigraphy performed on the first postoperative day. The uptake of fluorochrome labels immediately after transfer verified the adequacy of the periosteal circulation in maintaining viability and new osteoid formation throughout the full thickness of calvarial bone. The transplantation of free calvarial bone grafts was followed by necrosis of most cellular elements. This was demonstrated by an absence of fluorochrome uptake up to 19 days postoperatively and a predominance of empty lacunae and nonviable marrow.

Animals↗