Biomedical subjects

O Antonyshyn

Publications and source records attributed to O Antonyshyn.

At least 19 recordsLinked to original sources

PubMed2001

Nipple piercing may be contraindicated in male patients with chest implants.

The authors present a man who underwent chest augmentation and nipple piercing. The patient developed chronic nipple infection, which led to unnecessary invasive diagnostic procedures, serious implant infection, and eventually urgent explantation. This unfavorable scenario illustrates the distinct features of the procedure in men, which includes close proximity of the nipple to the implant and reduced awareness by health care providers. Based on this case the authors recommend avoiding nipple piercing in men with chest implants.

Cosmetic Techniques↗

PubMed1997

Progressive unilateral mandibular swelling in adolescence: a diagnostic dilemma.

Asymmetrical swelling of the mandible in adolescence may pose a significant diagnostic dilemma. The differential diagnosis ranges from traumatic, infectious, and metabolic processes to benign and malignant tumors. Among them, fibrous dysplasia, osteomyelitis, and malignancy may present with similar clinical and radiological features, making an accurate diagnosis quite difficult. This is an illustrative case involving a 14-year-old girl who initially presented with diffuse fibrous dysplasia of the mandible and in whom a superimposed osteomyelitis of the left side subsequently developed. Multiple investigations and several biopsies were required to arrive at a diagnosis. Similarities in clinical and radiographic findings of fibrous dysplasia, osteomyelitis, and malignancy are presented, and implications for treatment are discussed.

Adolescent↗

PubMed1996

The effects of temporalis muscle manipulation on skull growth: an experimental study.

Craniofacial reconstructive procedures are frequently associated with some dissection or transposition of the temporalis muscle. During active growth, such muscle manipulations may influence craniofacial development. The purpose of this study was to determine the effects of surgical manipulation of the temporalis muscle on craniofacial skeletal growth and morphology. Twenty-five New Zealand White rabbits underwent temporalis muscle surgery at 6 weeks of age. Group I (n = 6) underwent a sham procedure and served as a control group. Group II (n = 6) underwent simple elevation of the left temporalis muscle and immediate reapproximation. Group III (n = 7) underwent complete transection of the left temporalis muscle. Group IV (n = 6) underwent elevation of the left temporalis muscle and transposition to the left zygoma. Growth alterations were evaluated by standardized cephalometric x-rays. Baseline anteroposterior skull x-rays were performed preoperatively and every 3 weeks for the duration of the study. The study was terminated at 24 weeks of age. At this point, dry skull preparations were analyzed quantitatively by direct cephalometric evaluation. Manipulations of the temporalis muscle produce changes in local skull morphology and affect craniofacial growth. Skull length increases when the action of the temporalis muscle is interrupted either transiently or permanently, while skull width decreases. Temporalis muscle transposition to the orbit resulted in altered orbital dimensions. Qualitative analysis of local skull morphology further revealed posterior displacement of the external auditory meatus, a depressed temporalis fossa, and multiple resorption cavities following elevation of the temporalis muscle.

Animals↗

PubMed1996

Three-dimensional facial anthropometry using a laser surface scanner: validation of the technique.

Three-dimensional measurement and characterization of facial surface anatomy are fundamental to the objective analysis of facial deformity. However, existing clinical tools are inadequate. Recent innovations in laser scanning technology provide a potentially useful technique for accurate three-dimensional documentation of the face. The purpose of this study is to evaluate the reliability of interactive anthropometric landmark localization based on digitized three-dimensional facial images and to identify sources of error associated with the technique. Three-dimensional surface data were acquired using a commercially available laser scanning device (Cyberware 3030RGB digitizer), and all subsequent anthropometric analyses were performed interactively on the computer monitor. Four experimental conditions were studied, with 10 observations for each condition. A stable anthropomorphic model with prelabeled anatomic landmarks was scanned repeatedly under varying conditions of head inclination and position within the scanning gantry to determine the effect of these variables on the reliability of the technique. The scanning protocol was then repeated with the labels removed to evaluate the reliability of interactive localization of anthropometric landmarks on a digitized three-dimensional image. Optimal results were obtained with the head positioned in the center of the scanning gantry and with the Frankfort plane elevated 10 degrees from the horizontal. Under these circumstances, all 22 labeled landmarks were visualized and the variance in landmark localization was less than 0.6 mm in the x (horizontal), y (vertical), and z (depth) dimensions. Varying head position or inclination caused significant degradation of the digitized image. The variance of interactive landmark localization was analyzed in three dimensions. The reliability and the spatial orientation of variability were determined for each anthropometric point. These findings have direct implications for the clinical adaptation of this diagnostic tool for quantitative evaluation of facial surface anatomy.

Cephalometry↗

PubMed1995

Facial nerve palsy after mandibular fracture.

A 19-year-old man sustained a right parasymphyseal fracture and bilateral condylar neck fractures in a motor vehicle accident. The parasymphyseal fracture was treated by open reduction and internal fixation, and the subcondylar fractures were treated with closed reduction and maxillomandibular fixation. Three days postoperatively, a near-complete left facial nerve palsy developed. Facial nerve recovery was not full. The literature is reviewed, and possible mechanisms of this rare and devastating complication are discussed.

Adult↗

PubMed1995

The vascularized temporoparietal fascial flap for correction of the deep superior sulcus.

The deep superior sulcus is one of the more difficult problems to correct in the enophthalmic or anophthalmic orbit. Multiple procedures as well as materials have been proposed in recent years to address the cosmetic deformity. These methods have used a number of alloplastic and autogenous materials. Ideal correction of a soft tissue deformity uses well-vascularized autogenous tissue. This paper introduces the use of the temporoparietal fascial flap for correction of the deep superior sulcus. The advantages of this flap over other materials lies in its pliability, vascularity, thinness, ease of mobilization, and minimal subsequent donor site morbidity or deformity.

Adult↗

PubMed1995

Surgical management of abdominal wall disruption after blunt trauma.

Abdominal wall disruption following blunt trauma is a rare but challenging injury, both in the acute and convalescent phases. The present report describes the recent experience with this injury at a single adult trauma center. In a 22-month period, nine patients with traumatic abdominal wall disruption were managed. Flank and anteroinferior abdominal wall defects were most common. Associated injuries included 6 patients with a pelvic fracture and 4 patients with rectosigmoid injuries. Immediate primary repair of the defect was attempted in seven cases at the time of trauma laparotomy, but was difficult and often unsuccessful because of the related tissue destruction. Delayed abdominal wall repair was performed in patients with symptomatic disability (n = 5) and, if required, restoration of intestinal continuity was performed at a separate operation before abdominal wall repair. Delayed repair with autogenous tissue included the use of tensor fascia lata, rectus femoris muscle, rectus abdominis fascia, and latissimus dorsi muscle. Reconstruction with prosthetic mesh was required in two patients. One early and one late recurrence occurred, resulting in reoperation. In conclusion, traumatic abdominal wall disruption represents a complex challenge for both general and plastic surgeons. The key to successful surgical management seems to be a delayed staged repair with autogenous tissue when feasible.

Abdominal Muscles↗

PubMed1995

Comparison of laser Doppler flowmeter and radioactive microspheres in measuring blood flow in pig skin flaps.

Laser Doppler flowmetry is a noninvasive technique commonly used to monitor skin perfusion after free-tissue transfer or replantation in reconstructive surgery. Several investigators have expressed concern about the reliability of the quantitative value provided by laser Doppler flowmeters (LDF) and the extent to which they reflect nutrient blood flow. This experiment was designed to compare quantitatively the skin blood flow in the pig measured by LDF and by 15-micron radioactive microspheres (RMs). It was observed that the skin blood flow rates measured by LDF and RMs in the normal skin and in acute random-pattern and arterialized skin flaps were highly correlated (r = 0.93, P < .01). However, the skin blood flow rates measured by LDF were consistently higher (P < or = .05) than the corresponding flow rates measured by RMs, and this discrepancy increased considerably at low skin blood flow rates (< 2 mL/min/100 g). We speculated that the LDF most likely measured both nutrient and arteriovenous shunt flow in the skin and that this arteriovenous shunt flow at least in part caused the discrepancy in skin blood flow rates measured by the LDF and RMs because the 15-micron RMs are known to measure nutrient blood flow only. The inherent variations and errors in LDF technique were also discussed.

Animals↗

PubMed1995

Medial canthopexy: an experimental and biomechanical study.

Medial canthopexy is associated with a significant failure rate. A cadaveric study was undertaken to evaluate the biomechanics of the medial canthal tendon and three types of fixation devices for medial canthopexy. Eight medial canthal tendons were assessed in 4 fresh-frozen cadaver heads. The medial canthal tendon was found to be much stronger than previously suspected, with an average breaking strength of 36 newtons and an elongation of 6.25 mm. The tendon-bone complex was noted to be closely matched biomechanically. Three medial canthopexy techniques were then assessed: transnasal wire over a button, 1.7-mm screw fixation into the medial orbit, and the Mitek GII anchor. Their respective holding strengths were 74%, 92%, and 97% of that of the contralateral intact medial canthal tendon. The three types of fixation devices all provided excellent ultimate biomechanical strength.

Biomechanical Phenomena↗

PubMed1994

Temporal contour deformity after coronal flap elevation: an anatomical study.

Temporal contour deformity is defined as a concavity or depression in the temporal region located superior to the zygomatic arch and immediately posterior to the lateral orbital rim. The deformity can present as a consequence of extended coronal flap elevation for exposure of the lateral craniofacial skeleton. This study describes the anatomical and pathological features of the deformity and identifies causative factors. The series consists of unilateral temporal contour deformities after coronal flap elevation in 6 patients. A standardized data sheet was used in documenting details of the initial temporal dissection, clinical findings, and radiological features. Elevation of the temporal soft tissues was based on a qualitative analysis of coronal magnetic resonance imaging (MRI) scans comparing the affected and the unaffected temporal regions. The MRI studies demonstrated normal volume of the temporalis muscle in all cases, with no evidence of atrophy or disinsertion of the muscle. Diminution in the volume of the superficial temporal fat pad was identified in 4 patients, whereas inferior displacement or prolapse of the superficial temporal fat pad was noted in 2 patients.

Adipose Tissue↗

PubMed1993

Controlled bending of cranial bone grafts: a simple surgical technique.

The cranium serves as a primary bone graft donor site in reconstructive craniofacial surgery. However, the mechanical properties of cranial bone predispose to fragmentation when excessive bending forces are applied, or to a return to the original shape when bending forces are insufficient. The precise and sustained contouring of cranial bone therefore remains a practical clinical problem. This paper describes a simple surgical technique which relies upon the application of a miniplate to the cortical surface of the cranial bone segment prior to bending. The miniplate serves to reinforce the segment, allowing accurate shaping of cranial bone and maintenance of the newly acquired contour.

Biomechanical Phenomena↗

PubMed1993

Persistent posttraumatic orbital-antral fistula.

The case of a symptomatic persistent orbital--antral fistula after silicone orbital floor reconstruction is presented. Intermittent diplopia with Valsalva maneuvers was the patient's chief complaint. Periorbital cellulitis was a suspected complication of the fistula. This case emphasizes the importance of an often overlooked goal of orbital floor reconstruction, that is, isolation of the orbital cavity from the maxillary sinus. Greater care in positioning alloplastic implants may improve their function. Autogenous materials may be superior in orbital floor reconstruction.

Adult↗

PubMed1993

Use of porous high-density polyethylene implants in temporal contour reconstruction.

A temporal contour deformity is characterized by a concavity or depression in the soft-tissue contour of the temporal region and is associated with exaggerated relief of the lateral orbital rim and the zygomatic arch. The etiology of the deformity is varied, comprising any condition that results in displacement, atrophy, or absence of the temporalis muscle or the superficial temporal fat pad. We describe reconstruction of this deformity with porous high-density polyethylene implants in 16 consecutive patients, treated between July 1988 and September 1990. The etiology of the deformity and the surgical treatment are described. The results of treatment are assessed on long-term follow-up, ranging from 2 to 4 years postoperatively.

Adult↗

PubMed1992

Mucosal malignant melanoma of the paranasal sinuses.

We report a case of primary malignant melanoma arising in the mucosa of the nose and paranasal sinuses. Clinical presentation and course of this rare type of melanoma are described, and the surgical management is discussed.

Ethmoid Sinus↗

PubMed1991

Early definitive bone and soft-tissue reconstruction of major gunshot wounds of the face.

The use of craniofacial surgical techniques, extended open reduction, rigid fixation with plates and screws, and the replacement of severely damaged or missing bone with immediate bone grafting in the treatment of complex facial fractures has been applied to the management of severe gunshot wounds of the face. Early definitive bone and soft-tissue reconstruction has been performed in 37 patients. One-hundred and seventy-seven primary bone grafts were utilized in 33 patients for orbital, nasal, zygomatic, and maxillary reconstruction. Twenty-six patients required mandibular repair with compression or reconstruction plates. Soft-tissue reconstruction was provided by a combination of flaps. Four patients had extensive soft-tissue loss replaced by free vascularized omental flaps. The omentum provided circumferential coverage of the mandibular reconstruction and reconstruction of the floor of the mouth and was then tunneled in a circle through both cheeks into the middle and upper face. The omentum reconstructed deficits in the hard palate and upper buccal sulcus and was then wrapped around all zygomatic, orbital, and midfacial bone grafts and used to fill in dead space in the maxillary, ethmoid, and frontal sinuses. The omentum is not used to provide contour and bulk, but to cover bone grafts and plates and fill in dead space. Carefully shaped bone grafts provide the correct craniofacial scaffold. Early restoration of a midfacial bony scaffold and the prevention of soft-tissue contraction facilitate secondary reconstruction. Four late total nasal reconstructions with tissue-expanded forehead skin wrapped around bone grafts were performed.

Adolescent↗

PubMed1990

The importance of the zygomatic arch in complex midfacial fracture repair and correction of posttraumatic orbitozygomatic deformities.

Collapse of the zygomatic arch following trauma results in inadequate anteroposterior projection of the zygomatic body and an increase in facial width. Accurate assessment of the position of the zygomatic arch in relation to the cranial base posteriorly and the midface anteriorly is the key to the acute repair of complex midfacial fractures and the secondary reconstruction of posttraumatic deformities of the orbitozygomaticomaxillary complex. Loss of projection of the zygomatic arch may occur with injuries confined to the orbitozygomaticomaxillary region or in association with complex midfacial fractures. A safe anatomic approach to the zygomatic arch allows exact anatomic restoration of the zygomatic arch using miniplates and screws and results in the reconstruction of an outer facial frame with a correct anteroposterior projection and facial width. The zygomatic arch injury is diagnosed using axial CT scanning. Three-hundred and seventeen arches have been exposed through a coronal incision following acute trauma and 47 arches have been exposed in patients requiring late correction of a posttraumatic orbitozygomaticomaxillary deformity. Permanent palsy to the frontal branch of the facial nerve has occurred in one patient following the exact definition of the anatomy of this region.

Facial Bones↗

PubMed1989

Combined injuries of the cranium and face.

The neurosurgeon and plastic surgeon are increasingly called upon to manage the care of patients with combined injuries of the cranium and face. The authors briefly review the pathogenesis and classification of craniofacial fractures and outline historical approaches to them. Current principles of management are then discussed. Experience with 167 patients is presented with emphasis on surgical technique, the sequence of repair and early primary reconstruction. The controversial issue of fontal sinus fracture repair is addressed. The authors favour preservation of the frontal sinus cavity, where possible, and do not obliterate the nasofrontal duct. With injuries to the floor of the sinus, the base of the sinus and frontonasal duct are sealed with bone graft and a vascularised soft tissue flap and the sinus is cranialised. Immediate bone grafts, using split skull or rib, are used to reconstruct areas of bony destruction or loss. Ninety-eight patients required 402 grafts. Immediate bone grafting resulted in few complications and low incidence of secondary deformities needing correction.

Facial Bones↗

PubMed1989

Facial sensibility testing in the normal and posttraumatic population.

A reliable, reproducible, simple examination of facial sensibility is described. Evaluation of 60 healthy subjects established normal values, trends, and variations of facial sensibility. Comparison of these normal values with 20 posttraumatic patients revealed that postfacial fracture sensibility testing was abnormal. Abnormalities in pressure threshold testing was most consistently associated with functional sensory complaints. Twelve of the 20 patients had significant sensory complaints at one year following the trauma.

Adolescent↗