Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
J Craniofac Surg ; 29(3): 796-799, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29489569

RESUMO

Removal of the fronto-orbital bandeau is one of the most critical components for procedures designed to correct anomalies of the craniofacial skeleton and remodel the anterior calvarial vault. It is also used to improve exposure of the anterior cranial fossa. It is arguably one of the more difficult portions of some craniofacial procedures. While the technique for fronto-orbito-sphenoid osteotomy has been frequently described, it has only been minimally detailed. Separation of bone in this region remains challenging due to the bone thickness, adjacent vital structures, and limited direct visibility. The present paper describes the anatomy of this particular region, which the authors have termed the "triple point", to facilitate successful osteotomy and avoid potential injury.


Assuntos
Anormalidades Craniofaciais/cirurgia , Osso Frontal/cirurgia , Órbita/cirurgia , Osteotomia/métodos , Osso Esfenoide/anatomia & histologia , Osso Esfenoide/cirurgia , Fossa Craniana Anterior/anatomia & histologia , Fossa Craniana Anterior/cirurgia , Osso Frontal/anatomia & histologia , Humanos , Órbita/anatomia & histologia
2.
J Craniofac Surg ; 26(4): 1151-5, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26080146

RESUMO

Volunteer surgical missions to provide cleft care to patients in developing countries has been done successfully for a number of years. Similar missions that provide craniofacial surgery introduce a dramatic step up in complexity. While articles have addressed protocols for the safe delivery of cleft care around the world, little has been written on volunteer craniofacial surgical missions. Komedyplast was established in March 2001 as a 501c(3) nonprofit organization to provide craniofacial surgical care to underserved populations and educate local surgeons in craniofacial principles. During 9 annual missions, the organization has provided surgical care to more than 150 patients with various complex, congenital, craniofacial conditions. The article addresses important safeguards that have been implemented to maximize safety and minimize risk.


Assuntos
Anormalidades Craniofaciais/cirurgia , Países em Desenvolvimento , Missões Médicas/organização & administração , Voluntários , Humanos , Objetivos Organizacionais
3.
J Craniofac Surg ; 21(6): 1670-3, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21119397

RESUMO

PURPOSE: Frontal sinus fractures are relatively uncommon due to the high-impact force required to produce these. However, their management is quite complex, with the treatment algorithm incorporating many factors in which the status of the nasofrontal ducts is critically important. Traditionally, this has been evaluated by both axial and coronal computed tomographic (CT) scan views. Anatomically, we propose that this is better evaluated by coronal and sagittal CT views. We evaluated the role of sagittal CT scan views in determining the status of the nasofrontal ducts in patients with frontal sinus fractures. METHODS: A retrospective analysis examining 8 patients with frontal sinus fractures, from August 2004 to January 2008, was performed. Axial, coronal, and sagittal CT scan views were obtained routinely as part of the facial trauma workup. These views were assessed to determine the status of the nasofrontal ducts. The operative findings were also reviewed. RESULTS: Five of the 8 patients had displaced anterior and posterior table frontal sinus fractures. Of these, 4 required surgical intervention that included addressing the nasofrontal ducts. Two of the 8 patients had displaced anterior table fractures that required no intervention of the nasofrontal ducts. One patient had nondisplaced anterior and posterior table fractures and did not require surgery. The sagittal CT view clearly demonstrated the anatomy of the nasofrontal ducts in all 8 patients, including patients in whom the axial and/or coronal views were questionable. Intraoperatively, where the patency of the nasofrontal ducts was directly evaluated, there was a direct correlation with the sagittal image findings. CONCLUSIONS: The sagittal CT view provides invaluable information for evaluating the patency of the nasofrontal ducts in frontal sinus fractures. The ability to evaluate the frontal sinus in an anteroposterior dimension (the usual vector of the injury) and in a superoinferior dimension (the anatomic pathway of the ducts) is the reason for this imaging advantage.


Assuntos
Seio Frontal/lesões , Fraturas Cranianas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Seguimentos , Fixação Interna de Fraturas , Seio Frontal/diagnóstico por imagem , Seio Frontal/cirurgia , Humanos , Processamento de Imagem Assistida por Computador , Cuidados Intraoperatórios , Luxações Articulares/diagnóstico por imagem , Luxações Articulares/cirurgia , Masculino , Planejamento de Assistência ao Paciente , Estudos Retrospectivos , Fraturas Cranianas/cirurgia , Conchas Nasais/diagnóstico por imagem , Adulto Jovem
4.
J Craniofac Surg ; 21(4): 1153-7, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20613594

RESUMO

BACKGROUND: The sagittal plane computed tomographic (CT) scan has been proposed as the most important radiologic view in the diagnosis of orbital floor fractures. Before the advent of high-resolution CT, several articles were published in the radiology literature debating the need for direct sagittal views, which required cumbersome patient positioning. Today, the ability to easily create high-quality sagittal reformations requires reassessment of the importance of this view in the evaluation of orbital floor fractures. MATERIALS AND METHODS: Computed tomographic studies of 24 orbital floor fractures for which coronal and sagittal images were available were included. Five independent reviewers evaluated all image sets and recorded maximum fracture width, depth, posterior shelf length (PSL), and presence of medial wall fracture and of trap door deformity. Direct fracture width measurements were obtained via coronal images, whereas depth and PSL were measured directly in the sagittal plane. Indirect measurements in a given plane were obtained by counting the number of slices in which the fracture was present and multiplying by the slice thickness. Cronbach alpha analysis was used to provide an intraclass correlation coefficient, where greater values signify less interreviewer variability. RESULTS: The Cronbach alpha values for width, depth, and PSL were 64%, 59%, and 85% in the coronal view and 76%, 55%, and 51% in the sagittal view, respectively. The alpha values for presence/absence of medial wall fracture and trap door deformity were greater in the coronal view at 73% and 55%, respectively. The intrareviewer variability was not significantly correlated with the degree of patient rotation or CT scan slice thickness. The interreviewer variability was significantly less among attending reviewer then resident reviewers. CONCLUSIONS: There was less interreviewer variability when the measured variables were assessed indirectly (width was best assessed in the sagittal plane, and depth and PSL were best assessed in the coronal view). These findings support the idea that additional views aid the surgeon's ability to further define fracture anatomy than might be possible with any single view, thereby improving preoperative planning and reconstructive strategies.


Assuntos
Fraturas Orbitárias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Feminino , Humanos , Modelos Lineares , Masculino , Reprodutibilidade dos Testes
5.
Plast Reconstr Surg ; 125(6): 1661-1669, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20517089

RESUMO

BACKGROUND: Biomaterials have shown promise as potential substitutes for human tissue. Studies have demonstrated that attachment of a vascularized pedicle to dermal matrix grafts yields tissues that are resilient enough to patch hernia defects in rats. The purpose of this study was to examine the possibility of creating a viable composite graft completely from biomaterials. METHODS: Acellular dermal matrix was enveloped around a square wafer of hydroxyapatite bone substitute. This composite graft was inserted into an extraperitoneal pocket overlying the abdominal musculature. In 30 Sprague-Dawley rats, the superficial epigastric arteriovenous pedicle was dissected free and placed within the midportion of the matrix construct on one side of each animal. A second graft was inserted on the opposite side without the addition of a vascularized pedicle. Each animal served as its own control. Animals were divided into three equal groups and euthanized at time points of 30, 60, and 90 days. RESULTS: Histologic evaluation of specimens was performed using hematoxylin and eosin and trichrome stains. At 30 days, the dermal matrices demonstrated full-thickness cellular infiltration in all specimens. Collagen deposition was significantly greater in the experimental group at every time point. Cellularity was significantly greater in the experimental group at 30 days, but there were no significant differences between groups at 60 or 90 days. CONCLUSIONS: These results suggest that provision of an arteriovenous blood supply to nonbiologic tissue grafts significantly increases collagen deposition and early cellular deposition. Based on these findings, biomaterials may offer an exciting new method for tissue engineering.


Assuntos
Materiais Biocompatíveis/farmacologia , Colágeno/farmacologia , Derme/cirurgia , Durapatita/farmacologia , Neovascularização Fisiológica , Engenharia Tecidual/métodos , Animais , Capilares/fisiologia , Derme/irrigação sanguínea , Matriz Extracelular , Hérnia Abdominal/cirurgia , Ratos , Ratos Sprague-Dawley , Procedimentos de Cirurgia Plástica/métodos , Cicatrização
6.
J Craniofac Surg ; 21(1): 217-21, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20072007

RESUMO

Maxillofacial injuries in the partially edentulous patient present unique challenges that are best treated in conjunction with appropriate dental specialists. Many surgeons who treat complex maxillofacial injuries are not involved in the process of reconstruction of the occlusion and alveolus; however, dental rehabilitation is an important and often overlooked component of treatment of the partially edentulous patients. Working with dental specialists and understanding the role they play in perioperative planning, the plastic surgeon is in a position to optimize reconstruction and rehabilitation of these injuries. The appropriate dental specialists working with the plastic surgeon can provide the surgeon with the necessary orthodontic, prosthodontic, and radiologic expertise that is required to successfully treat these patients. In this article, the authors present their management algorithm for maxillomandibular rehabilitation in the partially edentulous patient and discuss the role of the appropriate dental specialists for obtaining optimal aesthetic and functional outcomes.


Assuntos
Algoritmos , Arcada Parcialmente Edêntula , Traumatismos Maxilofaciais/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Cefalometria , Implantes Dentários , Humanos , Traumatismos Maxilofaciais/complicações , Traumatismos Maxilofaciais/diagnóstico por imagem , Modelos Dentários , Ortodontia Corretiva , Radiografia Panorâmica , Tomografia Computadorizada por Raios X
7.
Plast Reconstr Surg ; 124(4): 1105-1117, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19935294

RESUMO

BACKGROUND: Empirical and experimental evidence abounds as to the negative effects of smoking on skin flaps. The ideal duration of preoperative smoking cessation is unclear. The present study evaluates the effect of various durations of smoking cessation on skin flap survival in a rat model. METHODS: Forty smoke-exposed and 10 non-smoke-exposed Sprague-Dawley rats were divided into five groups: controls and 0 days, 2 weeks, 4 weeks, and 8 weeks of smoking cessation. All animals had a dorsally based random pattern flap created and either bilateral pure axial superficial inferior epigastric (superficial inferior epigastric) flaps or a unilaterally superficial inferior epigastric axial with random component flap. The percentage of flap necrosis was assessed 2 weeks postoperatively. RESULTS: The mean amount of random skin flap necrosis was 16.6 +/- 13.0 percent, 30.3 +/- 8.4 percent, 27.6 +/- 7.9 percent, 27.1 +/- 6.1 percent, and 29.7 +/- 10.3 percent, respectively. There was significantly less flap necrosis in the controls than in all other groups (p < 0.03). There was no necrosis of any of the pure axial superficial inferior epigastric flaps. The mean amount of superficial inferior epigastric axial with random component skin flap necrosis was 11.1 +/- 6.2 percent, 31.1 +/- 6.0 percent, 36.0 +/- 8.4 percent, 21.7 +/- 4.0 percent, and 19.1 +/- 6.3 percent, respectively. All smoke-exposed groups had significantly greater flap necrosis than controls, with the exception of the 8-week group (p < 0.02). CONCLUSIONS: Smoking irreversibly increases the risk of flap necrosis in a random pattern flap out to 2 months of preoperative cessation. Preoperative smoking does not result in any necrosis of pure axial flaps. In axial with random component flaps, significant decreases in skin flap necrosis are not seen until 4 weeks of preoperative cessation.


Assuntos
Sobrevivência de Enxerto , Transplante de Pele , Abandono do Hábito de Fumar/estatística & dados numéricos , Retalhos Cirúrgicos , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
8.
Plast Reconstr Surg ; 124(4): 1118-1124, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19935295

RESUMO

BACKGROUND: Proper wound healing is pivotal to successful surgical outcomes. Previous studies have shown that growth factors can be used to enhance tissue repair under impaired healing conditions. However, because of limited delivery methods, the growth factors in these studies were delivered either topically or as a single local administration. METHODS: Sixty Sprague-Dawley rats were divided equally into five groups and served as untreated normal controls or were implanted subcutaneously with a novel sustained-release drug delivery system through a dorsal incisional wound. This system delivered either transforming growth factor (TGF)-beta alone, platelet-derived growth factor (PDGF) alone, or TGF-beta and PDGF in combination, or served as unloaded sham controls. Wound healing was impaired in all treated rats by the administration of cyclophosphamide on days 1, 3, and 5. Wound tensile breaking strength was determined on days 4, 7, and 14. RESULTS: Sustained release of either TGF-beta or PDGF alone not only failed to improve the healing of cyclophosphamide-induced impaired wound healing but resulted in a paradoxical decrease in wound tensile breaking strength by day 7. However, the combined delivery of both TGF-beta and PDGF improved wound healing and significantly increased wound tensile breaking strength by day 7. CONCLUSIONS: Sustained-release delivery of TGF-beta and PDGF in combination, but not separately, by a subcutaneously implanted drug delivery system significantly improves cyclophosphamide-induced impaired wound healing in rats.


Assuntos
Fator de Crescimento Derivado de Plaquetas/administração & dosagem , Fator de Crescimento Transformador beta/administração & dosagem , Cicatrização/efeitos dos fármacos , Animais , Ciclofosfamida/administração & dosagem , Preparações de Ação Retardada , Masculino , Ratos , Ratos Sprague-Dawley
10.
J Hand Surg Am ; 34(1): 102-7, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19058923

RESUMO

PURPOSE: Numerous flexor tendon repairs have been described. The ideal core flexor tendon repair optimizes strength characteristics while minimizing factors felt to contribute to adhesion formation. The present study compares ultimate tensile strength, gap strength, and surgical time in the Lahey repair, a new 4-strand flexor tendon repair, to 2 previously described techniques. METHODS: The flexor digitorum profundus tendons of 30 porcine forelimbs were repaired in situ using 1 of 3 flexor tendon repair techniques. The techniques compared included the 4-strand Kessler repair, the cruciate repair, and the experimental Lahey repair (4-strand Kessler with cruciate modification). Biomechanical testing was conducted in order to obtain initial gap strength and ultimate tensile strength. RESULTS: Although not significantly different from the 4-strand Kessler, the ultimate tensile strength of the Lahey repair was significantly greater than that of the cruciate repair. CONCLUSIONS: The Lahey flexor tendon repair has significantly greater ultimate tensile strength than the cruciate repair. These findings suggest that the Lahey repair can be considered a biomechanically favorable 4-strand technique for the repair of flexor tendon lacerations.


Assuntos
Técnicas de Sutura , Traumatismos dos Tendões/cirurgia , Resistência à Tração , Animais , Masculino , Modelos Animais , Estresse Mecânico , Suturas , Suínos , Tendões/fisiologia , Tendões/cirurgia
11.
Plast Reconstr Surg ; 122(4): 1036-1045, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18827634

RESUMO

BACKGROUND: Despite refinements in radiotherapy, radiation-impaired wound healing continues to be a major source of postoperative morbidity with few treatment options. The application of polypeptide growth factors has been investigated in both the clinical and laboratory settings. The authors used a novel sustained-release delivery system to examine the effect of transforming growth factor (TGF)-beta and fibroblast growth factor (FGF) on radiation-impaired wound healing in a rodent model. METHODS: Eighty Sprague-Dawley rats underwent dorsal skin surface irradiation of 2500 cGy using a medical linear accelerator producing energy of 6 MeV followed by creation of a full-thickness skin incision. Six groups of 16 animals underwent either sham irradiation (irradiation control); irradiation only; irradiation and unimpregnated delivery system only; or irradiation and either TGF-beta, FGF, or TGF-beta plus FGF combined. Four animals from each group were euthanized at 4, 7, 14, and 28 days, and the harvested specimens underwent ultimate tensile strength testing and histologic evaluation. RESULTS: All five irradiated groups had significantly lower ultimate tensile strength than the sham-irradiated control group at all time points (p < 0.05), thus validating the authors' model of radiation-impaired wound healing. Functional analysis demonstrated that all three growth factor-treated groups had significantly higher tensile strengths than either of the untreated irradiated groups at 14 days after wounding (p < 0.05). Histologic evaluation of the irradiated groups revealed increased cellularity and more organized collagen architecture of all treated groups when compared with the untreated groups, with the most pronounced differences seen at 7 days and 14 days after wounding. CONCLUSIONS: This study effectively demonstrates that TGF-beta and FGF act individually and synergistically when delivered locally by means of a sustained release system to improve ultimate tensile strength in an acute postirradiation impaired wound-healing model.


Assuntos
Fatores de Crescimento de Fibroblastos/farmacologia , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Lesões por Radiação/tratamento farmacológico , Fator de Crescimento Transformador beta/farmacologia , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões/tratamento farmacológico , Animais , Preparações de Ação Retardada , Modelos Animais de Doenças , Sistemas de Liberação de Medicamentos , Masculino , Ratos , Cicatrização/efeitos da radiação
12.
Plast Reconstr Surg ; 122(4): 1171-1180, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18827653

RESUMO

BACKGROUND: Slit ventricle syndrome and postshunt craniosynostosis are uncommon complications after shunting procedures for congenital hydrocephalus. Slit ventricle syndrome occurs as a complication in 1 to 5 percent of patients after shunting procedures for hydrocephalus during infancy. These patients usually have had a shunt in place for years, with overdrainage of cerebrospinal fluid resulting in very small ventricles. Excessive intracranial decompression may result in ventricular collapse with the formation of slit-like ventricles and cranial vault collapse with secondary craniosynostosis. METHODS: A retrospective review of 12 patients who had undergone cranial vault expansion for management of postshunt craniosynostosis and slit ventricle syndrome refractory to other treatment modalities was performed. All patients had initially been shunted for congenital hydrocephalus and subsequently underwent a mean of 4.9 shunt revisions before cranial vault expansion. RESULTS: All 12 patients demonstrated decreased ventricular volume, with noncompliant slit-like ventricles in nine of these patients. Five patients demonstrated pancraniosynostosis, three patients demonstrated multiple sutural fusion, and isolated sagittal synostosis occurred in two patients. Two patients appeared to have "functional" synostoses with narrowed, overlapping sutures that were not actually fused. Eleven patients underwent bilateral fronto-orbital advancement with frontotemporoparietal expansion; one patient underwent only posterior vault expansion. Seven of the 12 patients required a mean of 2.3 shunt revisions after cranial vault expansion; five patients did not require subsequent revisions. Improvement in cranial vault shape was achieved in all 12 patients, as was improvement of neurologic symptoms in nine of the 12 patients. CONCLUSIONS: Cranial vault expansion is a useful approach in the management of the restricted cranium associated with slit ventricle syndrome and postshunt craniosynostosis. This approach resulted in a decreased need for shunt revisions and improvement of neurologic symptoms and cranial vault shape.


Assuntos
Ventrículos Cerebrais/fisiopatologia , Derivações do Líquido Cefalorraquidiano/efeitos adversos , Craniossinostoses/cirurgia , Hidrocefalia/cirurgia , Crânio/cirurgia , Adolescente , Criança , Pré-Escolar , Craniossinostoses/etiologia , Descompressão Cirúrgica/efeitos adversos , Humanos , Lactente , Reoperação , Estudos Retrospectivos
13.
Plast Reconstr Surg ; 122(3): 749-754, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18766037

RESUMO

BACKGROUND: The concept of fat transplantation is not a new one in plastic surgery. Studies assessing fat graft viability following transplantation, however, have yielded conflicting observations. The present study evaluated the long-term fate of transplanted autologous fat using a novel facial augmentation model the authors have developed in the rabbit. METHODS: Thirteen adult New Zealand White rabbits underwent fat harvest using a modified Coleman technique. The left upper lip was used as the recipient site; the right upper lip remained unaltered in each case. After harvest from the groin, 1 ml of adipose tissue was transplanted to the left upper lip of each rabbit. Rabbits were euthanized 1, 3, 6, and 12 months after unilateral lip augmentation. Coronal sections of both upper lips were evaluated histologically; the right upper lip served as an internal control in each case. RESULTS: Histologic evaluation of specimens harvested at all postoperative time points demonstrated viable, transplanted fat graft in each case. Use of the nonoperated right lip allowed for paired evaluation of the experimental and control sides. A significant inflammatory response was present in the early phases, with evidence of neovascularization. Transplanted fat tissue was clearly visible in rabbits harvested 1 year postoperatively. CONCLUSIONS: The authors have established a novel, reproducible model with an internal control for long-term evaluation of transplanted fat. Histologic examination suggests an early inflammatory response to the injected fat followed by sequestration of nonviable tissue. The transplanted fat remained viable at 1 year, with good overall survivability and minimal fibrosis.


Assuntos
Tecido Adiposo/transplante , Tecido Adiposo/fisiologia , Animais , Face/cirurgia , Gorduras/análise , Lábio/cirurgia , Coelhos , Sobrevivência de Tecidos/fisiologia , Coleta de Tecidos e Órgãos , Transplante Autólogo
15.
Cleft Palate Craniofac J ; 45(2): 113-20, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18333646

RESUMO

OBJECTIVE: Despite cleft palate repair, velopharyngeal competence is not achieved in approximately 15% of patients, often necessitating secondary surgical correction. Velopharyngeal competence postrepair may require the conversion of levator veli palatini muscle fibers from injury-susceptible type 2 fibers to injury-resistant type 1 fibers. As an initial step to determining the validity of this theory, we tested the hypothesis that, in most cases, repair induces the transformation to type 1 fibers, thus diminishing susceptibility to injury. INTERVENTIONS: Single permeabilized levator veli palatini muscle fibers were obtained from normal palates and nonrepaired congenitally-clefted palates of young (2 months old) and adult (14 to 15 months old) goats and from repaired palates of adult goats (8 months old). Repair was done at 2 months of age using a modified von Langenbeck technique. MAIN OUTCOME MEASURES: Fiber type was determined by contractile properties and susceptibility to injury was assessed by force deficit, the decrease in maximum force following a lengthening contraction protocol expressed as a percentage of initial force. RESULTS: For normal palates and cleft palates of young goats, the majority of the fibers were type 2 with force deficits of approximately 40%. Following repair, 80% of the fibers were type 1 with force deficits of 20% +/- 2%; these deficits were 45% of those for nonrepaired cleft palates of adult goats (p < .0001). CONCLUSION: The decrease in the percentage of type 2 fibers and susceptibility to injury may be important for the development of a functional levator veli palatini muscle postrepair.


Assuntos
Fissura Palatina/cirurgia , Fibras Musculares de Contração Rápida/patologia , Fibras Musculares de Contração Lenta/patologia , Músculos Palatinos/patologia , Fatores Etários , Animais , Fenômenos Biomecânicos , Fissura Palatina/patologia , Modelos Animais de Doenças , Cabras , Contração Muscular/fisiologia , Desenvolvimento Muscular/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Fibras Musculares de Contração Lenta/fisiologia , Músculos Palatinos/crescimento & desenvolvimento , Palato/patologia , Palato Duro/cirurgia , Palato Mole/cirurgia , Sarcômeros/patologia , Sarcômeros/fisiologia , Estresse Mecânico , Fatores de Tempo
16.
Plast Reconstr Surg ; 121(4): 1328-1334, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18349652

RESUMO

BACKGROUND: Failure of palatal shelf fusion at the precise gestational time point when shelf elevation and migration normally occur results in clefting. The present study defined the mechanism of clefting in the congenital caprine model by evaluating the temporal sequence of palatal shelf fusion. METHODS: Six Spanish-type goats pregnant with twins were gavaged for 10 days (gestational days 32 to 41) with anabasine. Goats were examined with ultrasound throughout this period to assess fetal movement and evaluated histologically. Twelve untreated, unclefted fetuses served as controls. RESULTS: After anabasine induction, real-time ultrasound confirmed a dramatic decrease in fetal movement. Hyperflexion of the neck occurred throughout the experimental period compared with control fetuses, in which spontaneous neck movements occurred. Histologic evaluation of the induced fetuses demonstrated the tongue wedged between the palatal shelves throughout the period of fusion. The shelves remained vertically oriented without elevation, ultimately resulting in clefting. The unclefted, control group demonstrated progressive elevation and migration of the palatal shelves between gestational days 38 and 40, with contact and fusion of the medial edge epithelia in the midline. CONCLUSIONS: Palatal clefting in the congenital caprine model occurred concomitant with reduced fetal movement. Resultant neck hyperflexion causes the tongue to obstruct medial migration of the palatal shelves and fusion, whereas the shelves themselves are either directly prevented from elevation secondary to anabasine impairment or indirectly secondary to the obstructing tongue. Although the molecular mechanism for the teratogenic effects of anabasine remains elusive, the authors have demonstrated an association between reduced fetal movement and palatal clefting in their congenital caprine model.


Assuntos
Fissura Palatina/embriologia , Animais , Modelos Animais de Doenças , Cabras/embriologia
17.
Ann Plast Surg ; 60(2): 188-93, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18216514

RESUMO

Inherent differences in the levator veli palatini (LVP) muscle of cleft palates before palatoplasty may play a role in persistent postrepair velopharyngeal insufficiency (VPI). Contractile properties of LVP muscle fibers were analyzed from young (2-month) normal (YNP), young congenitally cleft (YCP) and again on the same YCP subjects 6 months after palatoplasty, mature repaired palate (MRP). The cross-sectional area and rate of force development (ktr) were measured. Specific force (sF(0)) and normalized power (nP(max)) were calculated. Using k(tr) to determine fiber type composition, YNP was 44% type 1 and 56% type 2, while YCP was 100% type 2. Two MRP subjects shifted to 100% type 1; 1 demonstrated increased resistance to fatigue. No differences in sF(0) were observed. nP(max) increased with presence of type 2 fibers. The persistent state of type 2 fibers following palatoplasty leads to increased fatigue in the LVP of MRP subjects and may cause VPI symptoms.


Assuntos
Fissura Palatina/fisiopatologia , Contração Muscular/fisiologia , Fibras Musculares Esqueléticas/fisiologia , Músculos Palatinos/fisiopatologia , Animais , Fissura Palatina/cirurgia , Modelos Animais de Doenças , Cabras , Contração Isométrica/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Fibras Musculares Esqueléticas/química , Fibras Musculares de Contração Lenta/fisiologia , Permeabilidade , Insuficiência Velofaríngea/patologia , Insuficiência Velofaríngea/fisiopatologia
18.
Plast Reconstr Surg ; 119(6): 1685-1694, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17440342

RESUMO

BACKGROUND: Analysis of the composition of muscle fibers constituent to a cleft palate could provide significant insight into the cause of velopharyngeal inadequacy. The authors hypothesized that levator veli palatini muscle dysfunction inherent to cleft palates could affect the timing and outcome of cleft palate repair. METHODS: Single, permeabilized muscle fibers from levator veli palatini muscles of three normal (n = 19 fibers) and three chemically induced congenital cleft palates (n = 21 fibers) of 14-month-old goats were isolated, and contractile properties were evaluated. The maximum isometric force and rate constants of tension redevelopment (ktr) were measured, and the specific force and normalized power were calculated for each fiber. RESULTS: The ktr measures indicate that cleft fibers are predominantly fast-fatigable; normal fibers are slow fatigue-resistant: after a 10-minute isometric contraction, fibers from cleft palates had a loss of force 16 percent greater than that from normal palates (p = 0.0001). The cross-sectional areas of the fibers from cleft palates (2750 +/- 209 microm2) were greater (p = 0.05) than those from normal palates (2226 +/- 143 microm2). Specific forces did not differ between the two groups. Maximum normalized power of fibers from cleft palates (11.05 +/- 1.82 W/l) was greater (p = 0.0001) than fibers from normal palates (1.60 +/- 0.12 W/l). CONCLUSIONS: There are clear physiologic differences in single muscle fibers from cleft palates and normal palates: cleft palate fibers are physiologically fast, have greater fatigability, and have greater power production. Detection of functional and/or fiber type differences in muscles of cleft palates may provide preoperative identification of a patient's susceptibility to velopharyngeal inadequacy and permit early surgical intervention to correct this clinical condition.


Assuntos
Fissura Palatina/patologia , Contração Isométrica/fisiologia , Fadiga Muscular/fisiologia , Músculos Palatinos/patologia , Análise de Variância , Animais , Animais Recém-Nascidos , Fissura Palatina/fisiopatologia , Modelos Animais de Doenças , Feminino , Cabras , Imuno-Histoquímica , Fibras Musculares Esqueléticas/patologia , Fibras Musculares Esqueléticas/fisiologia , Técnicas de Cultura de Órgãos , Músculos Palatinos/fisiologia , Probabilidade , Distribuição Aleatória , Valores de Referência , Sensibilidade e Especificidade , Espanha , Estatísticas não Paramétricas
19.
Cleft Palate Craniofac J ; 44(2): 216-22, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17328650

RESUMO

OBJECTIVE: Levator veli palatini muscles from normal palates of adult humans and goats are predominantly slow oxidative (type 1) fibers. However, 85% of levator veli palatini fibers from cleft palates of adult goats are physiologically fast (type 2). This fiber composition difference between cleft and normal palates may have implications in palatal function. For limb muscles, type 2 muscle fibers are more susceptible to lengthening contraction-induced injury than are type 1 fibers. We tested the hypothesis that, compared with single permeabilized levator veli palatini muscle fibers from normal palates of adult goats, those from cleft palates are more susceptible to lengthening contraction-induced injury. INTERVENTIONS: Congenital cleft palates were the result of chemically-induced decreased movement of the fetal head and tongue causing obstruction of palatal closure. Each muscle fiber was maximally activated and lengthened. OUTCOME MEASURES: Fiber type was determined by contractile properties and gel electrophoresis. Susceptibility to injury was assessed by measuring the decrease in maximum force following the lengthening contraction, expressed as a percentage of the initial force. RESULTS: Compared with fibers from normal palates that were all type 1 and had force deficits of 23 +/- 1%, fibers from cleft palates were all type 2 and sustained twofold greater deficits, 40 +/- 1% (p = .001). CONCLUSION: Levator veli palatini muscles from cleft palates of goats contain predominantly type 2 fibers that are highly susceptible to lengthening contraction-induced injury. This finding may have implications regarding palatal function and the incidence of velopharyngeal incompetence.


Assuntos
Fissura Palatina/fisiopatologia , Contração Muscular/fisiologia , Fibras Musculares Esqueléticas/fisiologia , Músculos Palatinos/fisiopatologia , Animais , Modelos Animais de Doenças , Eletroforese em Gel de Poliacrilamida , Feminino , Cabras , Contração Isométrica/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Fibras Musculares de Contração Lenta/fisiologia , Cadeias Pesadas de Miosina/análise , Palato Mole/fisiopatologia , Permeabilidade
20.
Plast Reconstr Surg ; 118(1): 81-93, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16816677

RESUMO

BACKGROUND: Midfacial hypoplasia and growth disturbances following cleft palate repair are well-known consequences of the maxillary scarring inherent with each repair technique. The present study investigated the influence of in utero palatoplasty, and cleft repair in 6-week-old goats, on midfacial growth and bony palatal development in the authors' congenital caprine cleft palate model in an effort to identify an inherent component of facial growth impairment associated with the cleft anomaly. METHODS: At 85 days' gestation, eight clefted fetuses underwent in utero cleft palate repair using a modified von Langenbeck technique; eight fetuses remained as unrepaired controls. At 6 weeks of age, eight goats underwent cleft palate repair using the same technique. All goats were euthanized at 6 months of age; dry skull measurements and cephalometric analyses were performed. RESULTS: Fetal Repairs: Both repaired and unrepaired clefted goats demonstrated significant evidence of maxillary hypoplasia compared with unclefted controls. Repaired goats showed a decrease of 15.7 percent in maxillary length, and unrepaired clefted goats showed a decrease of 18.0 percent in maxillary length, compared with unclefted controls. There was no significant difference in maxillary growth between the repaired and unrepaired clefted groups. Bony cleft width was reduced by 48 percent anteriorly and 60 percent posteriorly. Thirty-seven percent of repaired congenital clefts demonstrated partial bony fusion involving 10 to 70 percent of the palatal length. This was accompanied by an 8.8 percent decrease in maxillary width at the level of the third molar crown compared with unclefted controls and an 18.3 percent decrease in maxillary width compared with unrepaired clefted goats. Unrepaired clefted goats demonstrated neither a decrease in maxillary width nor any narrowing or fusion of the bony cleft. Newborn Repairs: Significant midfacial growth impairment was seen in animals that underwent cleft palate repair at 6 weeks of age compared with those repaired in utero and with unclefted controls. Repaired clefted goats demonstrated a significant decrease in maxillary length by 29.5 percent compared with unclefted controls and 16.4 percent compared with the group repaired in utero. Repaired goats also demonstrated a significant decrease in maxillary width in the transverse dimension at the level of the third molar. A decrease in maxillary width of 25.3 percent was seen compared with the unclefted controls and 18.1 percent compared with the fetal repairs. Bony cleft width was reduced by 32 percent anteriorly and 27 percent posteriorly following repair at 6 weeks of age. Although all goats demonstrated narrowing following repair, partial bony palatal fusion was not seen in this group. CONCLUSIONS: In utero cleft palate repair does not contribute to impairment of midfacial growth. The authors attribute this finding to the scarless nature of mucoperiosteal healing in the privileged fetal environment. However, the cleft palate anomaly does have an inherent component of facial dysmorphology that is evidenced as maxillary hypoplasia or retrusion in unrepaired clefted animals. Cleft repair in the newborn period, or thereafter, results in midfacial growth impairment in a manner similar to that seen clinically. The authors attribute this finding to the scarring that routinely accompanies conventional palatoplasty. The combination of the growth impairment inherent in the cleft anomaly and that attributable to postnatal repair scarring yields the midfacial retrusion commonly associated with cleft palate.


Assuntos
Fissura Palatina/cirurgia , Doenças Fetais/cirurgia , Feto/cirurgia , Desenvolvimento Maxilofacial , Animais , Animais Recém-Nascidos , Cefalometria , Fissura Palatina/embriologia , Face , Feto/fisiologia , Cabras , Maxila/crescimento & desenvolvimento , Maxila/cirurgia , Modelos Animais , Período Pós-Operatório , Cicatrização/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA