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Biomedical subjects

P K Sullivan

Publications and source records attributed to P K Sullivan.

At least 19 recordsLinked to original sources
PubMed2001

The optimal medial osteotomy: a study of nasal bone thickness and fracture patterns.

The use of medial osteotomies as an adjunct in rhinoplasty represents an ongoing challenge to the surgeon. Despite previous descriptions, it remains difficult to obtain a consistent, aesthetically pleasing result. Nasal skin is thin and unforgiving in the region of the medial osteotomy, thus irregularities may be created. Also, bony collapse is possible with overmobilization of the osteotomy segment. The present study was undertaken to understand nasal bone thickness and osteotomy fracture tendencies to provide consistent and aesthetically pleasing results when performing medial osteotomy. Seventeen cadavers with known demographics were studied. Left heminoses were skeletonized to bone; 1-mm drill holes in a 3 x 3-mm grid were made from the midline up to the laterocephalic extent of the bony vault. On right hemi- noses, medial osteotomies were performed at either 0 or 15 degrees from the midline and combined with "low-to-low" lateral osteotomies with digital greenstick infracture. Soft tissue was removed to examine fracture patterns and narrowing. A transition in bone thickness was found both with increasing thickness from caudal to cephalic and lateral to medial, leading to a natural cleavage plane, evident in all 17 cadavers. Zero-degree osteotomies caused contour irregularities with rocker-like deformities in seven of eight noses. Fifteen-degree medial osteotomies produced narrowing without contour deformities in all cases (nine of nine), which was significantly different from the result with 0-degree osteotomies (p = 0.0004). Sharp, thin osteotomes were preferred to perform the osteotomies. The order of the osteotomies (medial, lateral) did not affect resultant narrowing or cause contour deformity. Fifteen-degree medial osteotomies followed the natural cleavage plane formed by bone thickness transition, whereas 0-degree osteotomies cut into much thicker bone, resulting in thick spicules of bone attached to the mobilized segment. When 15-degree medial osteotomies were combined with low-to-low lateral osteotomies with digital greenstick infracture, the resultant narrowing was sufficient and the greenstick reliable and controlled, without any evidence of contour deformity. The smooth contour is readily apparent clinically.

Adult↗
PubMed2001

Facial rejuvenation: the art and science of cosmetic surgery.

Our objective is to present an overall, customized treatment plan for the patient to address his or her concerns in the most comprehensive way possible. We then allow the patient to choose if he or she would like to have this done with one procedure and one recovery period. This one treatment may put the patient far enough ahead of the aging curve that they may never desire another surgery. The patient could also choose to have the surgery broken up into multiple treatments in a more piecemeal fashion. This would necessitate multiple recovery periods and during the intervening time, there may be an artistic mismatch between the rejuvenated area that has been treated and adjacent untreated areas that still manifest all the signs of the aging process. The choice is left to the patient.

Aged↗
PubMed2001

Artistic shaping of key facial features in children and adolescents.

Facial aesthetics can be enhanced by otoplasty, rhinoplasty and genioplasty. Excellent outcomes can be obtained given appropriate timing, patient selection, preoperative planning, and artistic sculpting of the region with the appropriate surgical technique. Choosing a patient with mature psychological, developmental, and anatomic features that are amenable to treatment in the pediatric population can be challenging, yet rewarding.

Adolescent↗
PubMed2000

A comparative study of the effects of UVC irradiation on select procaryotic and eucaryotic wound pathogens.

Managing wounds infected with a mixture of several types of microorganisms such as bacteria (procaryotes) and fungi (eucaryotes) is a challenging clinical situation. The purpose of this study was to determine the effectiveness of ultraviolet light (UVC) in eradicating select procaryotic and eucaryotic organisms, in both pure culture and mixed cultures in vitro. Five replications of each organism or mixture of organisms (10(6) organisms/mL singly or 10(15) organisms/mL mixed culture) were plated. The cultures were treated with a UVC light 1 inch from the surface. Irradiation times were 0, 2, 3, 4, 5, 15, 30, 45, 60, 90, 120, and 180 seconds. Bacterial cultures were incubated and colony counts performed. Upon exposure to UVC, a 99.9% kill rate was obtained at 3 to 5 seconds for the procaryotic organisms (Pseudomonas aeruginosa and Mycobacterium abscessus) tested. However, 15 to 30 seconds of UVC treatment was required to obtain 99.9% kill of the eucaryotic organisms (Candida albicans, Aspergillus fumigatus) tested. This study demonstrates a decreasing sensitivity of evolutionarily more complex organisms to UVC. This study also provides further evidence that short exposure times to UVC are detrimental to procaryotic and simple unicellular eucaryotic organisms while sparing more complex multicellular organisms.

Aspergillus fumigatus↗
PubMed1999

Lateral nasal osteotomies: implications of bony thickness on fracture patterns.

Precise lateral nasal osteotomies combined with digital greenstick infracture can be a key feature in determining the success of a rhinoplasty procedure. This procedure may be difficult to perform consistently because the surgeon relies on tactile cues transmitted through intact soft tissue. In 17 cadavers with known demographics, bone fracture patterns after lateral osteotomy and digital greenstick infracture were studied and compared with measured lateral bone pyramid thicknesses. One side of each nose served to measure lateral wall thicknesses by drilling holes in a grid pattern and taking depth gauge measurements. Contralaterally, lateral osteotomy with digital greenstick infractures were performed. Consistent patterns of bone thickness were found. Bone was thinner near the pyriform aperture with a high fragmentation rate after osteotomy. Cephalocaudal thinning of the lateral bony pyramid near the medial canthus corresponded to the zone of greenstick fracture in 14 of 14 noses. Two major fracture pattern groups were noted. When lateral osteotomy was taken to the level of the medial canthus vertically, the greenstick fracture was consistent and predictable based on the transition in bone thickness from the radix area down across the lateral bony vault in untraumatized white cadavers.

Fractures, Bone↗
PubMed1999

The effects of UVC irradiation on group A streptococcus in vitro.

Streptococcus pyogenes (group A streptococcus--GAS) is a common cause of necrotizing fasciitis (NF)--a severe infection of the subcutaneous soft tissue. The purpose of this study was to determine if the topical therapy ultraviolet light C (UVC) is effective in killing GAS in vitro and to evaluate the most effective treatment parameters for use with UVC therapy. Five replications of GAS at 10(8) organisms/mL were plated. The cultures were treated with a UVC light 1 inch from the surface. Irradiation times were as follows: 0, 2, 3, 4, 5, 15, 30, 45, 60, 90, 120, and 180 seconds. Bacterial cultures were incubated and colony counts performed. A second set of GAS cultures were exposed to UVC for 30, 90, and 120 seconds either once daily (qd) or twice daily (bid). Kill rates were 99.9% for GAS at 4 seconds to 180 seconds. Kill rates of 99.9% were also obtained at 30 seconds and 90 seconds when UVC treatment was given either qd or bid. This data indicates that UVC is bactericidal for GAS at times as short as 4 seconds. In addition, UVC treatment was not effective when administered through thin film dressings.

Bacteriological Techniques↗
PubMed1998

The effects of ultraviolet radiation on antibiotic-resistant bacteria in vitro.

Wound infections produced by antibiotic-resistant bacterial strains are particularly difficult to manage. This study examined the effectiveness of ultraviolet (UV) light treatment in killing antibiotic-resistant strains of Staphylococcus aureus and Enterococcus faecalis in vitro. Between 2 and 5 replications of each organism at 10(8) organisms/ml were prepared and plated on sheep blood agar medium and treated with UV light (254 nm, 15.54 mW/cm2 output). Irradiation times were 0, 2, 5, 8, 15, 30, 45, 60, 90 or 120 seconds. Bacterial cultures were then incubated at 35 degrees C for 24 hours. Kill rates were 99.9 percent for the methicillin-resistant strain of S. aureus (MRSA) at 5, 8, 15, 30, 45, 60 seconds and 100 percent at 90 and 120 seconds. Kill rates were 99.9 percent at 5, 8, 15, 30 seconds for vancomycin-resistant E. faecalis (VRE) and 100 percent at 45, 60, 90, 120 seconds. Similar results were found with UV light treatment of the antibiotic-susceptible strains of S. aureus and E. faecalis. A significant difference in kill rates at 30 seconds of UV exposure was detected between the antibiotic-resistant strain of S. aureus and the antibiotic-resistant strain of E. faecalis (Student's t test, p < 0.01). Significant differences were also detected in the kill rates at 30 second exposure times for the antibiotic-susceptible strains of S. aureus and E. faecalis. These findings suggest that the Enterococcal bacteria is more susceptible to the killing effects of UV. This data also suggests that UV light at 254 nm is bactericidal for antibiotic-resistant strains of S. aureus and E. faecalis at times as short as 5 seconds and that the enterococcal bacteria is more susceptible to the killing effects of UV. With recommended patient treatment times for infected wounds being significantly longer than 5 seconds, this data indicates that patient treatment times need to be re-examined.

Cross Infection↗
PubMed1996

Optimizing bone-graft nasal reconstruction: a study of nasal bone shape and thickness.

Nasal reconstruction may best be carried out with bone grafting in certain cases of loss of structural support. In order to optimize both the aesthetic and functional results of bone-graft nasal reconstruction, we studied the shape and thickness of the normal human nasal bone. Sixty Caucasian skull nasal bones were measured by width throughout their length at three planes of depth. Seventeen Caucasian cadaver nasal bones were examined to determine the thickness of the bone throughout its length at three sagittal planes. The results showed that the nasal bone was widest at the nasofrontal suture (14 mm), narrowest at the nasofrontal angle (10 mm), and then widened again to a maximum width of 12 mm about 9 to 12 mm inferior to the nasofrontal angle. The nasal bone was thickest superiorly at the nasofrontal angle (average 6 mm) and progressively thinned toward the tip. It was 3 to 4 mm thick in the critical area where screws are most commonly placed for fixation (5 to 10 mm inferior to the nasofrontal angle). From these data, three-dimensional models of the normal nasal bone shape were formulated and used in clinical bone-graft cases.

Bone Transplantation↗
PubMed1995

Bulbous nasal tip: an anatomical and histological evaluation.

The operative management of the bulbous nasal tip is a challenging and unsolved problem. Surgical alteration often leads to disappointing postoperative results. Surgical options for the soft tissue range from tip defatting and scoring of the dermis to no soft-tissue removal at all. The goal of this study was to determine anatomically and histologically the exact nature of the nasal tip soft tissue. Forty-two tissue specimens were obtained from 23 patients undergoing nasal surgery. These specimens were stained with standard hematoxylin and eosin stain and a combined Mallory trichrome and elastic stain and examined under light microscopy by a pathologist. Qualitative assessment of the tissue types present demonstrated that collagenous fibrous tissue was abundant. Skeletal muscle was present in significant amounts and in some cases made up the majority of the subdermal tissue. The adipose tissue component was less than expected.

Adipose Tissue↗
PubMed1994

Cranio-orbital reconstruction: safety and image quality of metallic implants on CT and MRI scanning.

A study was undertaken to evaluate the safety of magnetic resonance imaging (MRI) of metallic implants used in cranio-orbital reconstruction (stainless steel wire and titanium and Vitallium plates) and also to compare the degree of artifact created on computed tomographic (CT) scanning and MRI by each material. Samples of each material were tested for deflection (movement) in a 1.5-T MRI field and for temperature change under conditions simulating a clinical MRI scan. None of the materials exhibited any deflection, and none exhibited any significant temperature change compared with water. Standardized bars of each material and commonly used, commercially available titanium and Vitallium implants (plates, mesh) were evaluated for artifact. On blinded evaluation by three radiologists and on quantitative computer analysis of the CT images, the stainless steel produced the most artifact on both CT scan and MRI, followed by the Vitallium, with the least artifact caused by titanium. All the titanium images were felt to be acceptable to detect orbital pathology, while only the images with the thinnest Vitallium (micromesh) implant were acceptable.

Animals↗
PubMed1993

Issues and controversies in the management of cleft palate.

Cleft palate management is complex. There is no current agreement on the appropriate treatment strategy. Extensive disagreement on the pathophysiology, timing of intervention, and techniques of surgical repair have added to the confusion. To provide a comprehensive guide to the management of cleft palate is difficult. However, several main points should be emphasized. Normal speech should be the most important consideration in the therapeutic plan. Growth disturbance should be minimized, but not at the expense of speech impairment, because the facial distortion can be satisfactorily managed with further surgery, whereas speech impairment can often be irreversible. We believe repair of cleft palate to establish a competent velopharyngeal sphincter should be completed from 6 to 12 months of age. This is done early enough to minimize the development of an often irreversible pathologic compensatory speech pattern, but late enough not to increase significantly the surgical risk to the infant. Surgical interventions should be designed to cause minimal disruption of the palate, to decrease the severity of subsequent growth problems. There is a need for well-controlled, prospective studies to establish the validity of the widely different claims of superior results from various techniques. We believe strongly that cleft patients should be managed in a center with a multidisciplinary team. The benefits of these teams have been elaborated. Cleft palate embodies one of the major tenets of plastic surgery, the achievement of an aesthetic result with minimal interference with function. Cleft palate remains a significant and interesting challenge for current and future plastic surgeons.

Cleft Palate↗
PubMed1993

Bone-graft reconstruction of the monkey orbital floor with iliac grafts and titanium mesh plates: a histometric study.

Bone-graft reconstruction of large orbital defects has been difficult because of a lack of marginal support of the grafts and unpredictable resorption. A titanium mesh orbital plate has been developed to provide this marginal support for bone grafts. However, the problem of unpredictable bone-graft resorption remains. To determine if this plate has any effect on graft resorption, this study was designed to quantitate the dimensions and composition of bone autografts (1) with and without titanium plate support and (2) in the anterior and posterior orbit. Bilateral full-thickness large orbital floor defects were surgically created in five monkeys, and a titanium orbital floor plate was fixed with screws into the right orbit. Two iliac crest grafts were measured and placed transversely and without fixation in each orbit, one anterior and the other posterior to the axis of the globe. The orbits were retrieved 28 weeks after surgery and were analyzed histologically and histometrically. Comparison of the supported and nonsupported grafts revealed no differences in their histologic appearance. There were three significant histometric findings: (1) resorption of bone was similar for those grafts which spanned an orbital floor defect and those which were supported by a titanium plate; (2) resorption of grafts in the posterior orbit did not differ from that of grafts in the anterior orbit; and (3) resorption of approximately one-third of bone-graft thickness and width had taken place during the 28-week study interval. We conclude that the benefits of bone-graft support by a titanium mesh orbital floor plate are not offset by any alteration in bone-graft resorption.

Animals↗
PubMed1992

Mandibular osteotomies for tumor extirpation: the advantages of rigid fixation.

Adequate exposure of intraoral tumors occupying the posterior oral cavity, base of tongue, tonsil, and superior hypopharynx for wide-field primary surgical resection is critical to precise tumor ablation. The exposure resulting from a mandibular osteotomy has greatly assisted the tumor ablation of these areas. This procedure has also been beneficial in providing exposure to the anterior skull base, pterygomaxillary, and infratemporal space, clivus, and nasopharynx. In evaluating various osteotomy sites and methods of fixation, we reviewed 26 patients treated for benign or malignant neoplasia of the head and neck requiring mandibulotomy. The osteotomy complication rate was 2 (29%) of 7 for wire osteosynthesis and 1 (5.3%) of 19 for plate osteosynthesis. All patients with osteotomy complications had received preoperative radiation therapy. The one complication in the plated group was associated with a lateral stairstep osteotomy and two screws on either side of the osteotomy. This study suggests advantages of absolute rigid internal fixation of mandibular osteotomies used for tumor ablation. It is also concluded that a midline osteotomy reapproximated with rigid internal fixation has the benefits of 1. primary bone healing by means of plating counteracting the balanced forces acting on the symphysis; 2. improved reapproximation with minimal bony loss, improving occlusion; 3. decreased incidence of osteoradionecrosis as the symphysis lies outside the usual radiation ports; 4. preservation of the neurovascular bundle; and 5. maintenance of osteotomy-site immobility in an infected field. This review helped identify surgical techniques that decrease the complications that are commonly associated with mandibular osteotomies for precise tumor ablation.

Adult↗
PubMed1991

The resection of orbicularis oculi muscle from the upper eyelid in experimental surgery on the monkey.

The purpose of this study was to determine the maximum amount of orbicularis oculi muscle that may safely be resected from the upper eyelid without causing functional abnormalities. Measured amounts of that muscle were surgically excised from both upper eyelids in six cynomolgus monkeys. All the eyelids were photographed and videotaped at progressively increased intervals to permit the evaluation of wound healing, scarring, and function. Our preliminary results revealed that the excision of preseptal and partial supraorbital orbicularis oculi muscle, preseptal and complete supraorbital muscle, or pretarsal muscle only did not result in lagophthalmos. Complete resection of pretarsal, preseptal, and supraorbital orbicularis oculi did result in lagophthalmos but caused no corneal injury. The orbicularis oculi muscle in the cynomolgus monkey is similar to that in humans, but it is not yet clear whether our findings in the monkey are applicable in humans. A determination of the maximum amount of orbicularis oculi muscle that can safely be excised in humans would enable plastic surgeons to better understand and develop techniques for eyelid reconstruction and blepharoplasty.

Animals↗
PubMed1990

Maxillofacial fractures in the elderly: a comparative study.

Previous maxillofacial trauma research has dealt primarily with facial bone fractures in the general population. Very few studies have specifically addressed maxillofacial fractures in the elderly. We compared 45 elderly (65 years of age or older) and 201 younger adult (16 to 64 years of age) patients admitted to our hospital with maxillofacial fractures. The percentage of patients admitted with nasal bone fractures was much greater in the elderly population, while mandibular fractures were more common in the adult group. Motor vehicle accidents accounted for over half the injuries in both groups, while falls were more prevalent in the elderly. Management of the elderly patient may be complicated by their associated injuries or underlying medical problems, perhaps partially accounting for their longer median length of hospital stay. The elderly are a unique subpopulation of maxillofacial fracture patients and deserve further study regarding their injuries and optimal methods for treatment.

Accidental Falls↗