Search PubMed⌕ Search

Biomedical subjects

M T Longaker

Publications and source records attributed to M T Longaker.

At least 145 records · Page 8Linked to original sources
PubMed1998

Evolving thoughts on correcting posttraumatic enophthalmos.

Posttraumatic enophthalmos, though a difficult problem, is correctable by traditional craniofacial techniques. Based on considerable experience with these wide exposure operations, our surgical strategy has evolved and has been distilled into one of limited exposure via lateral upper blepharoplasty, transconjunctival without canthotomy and intraoral incisions. The advantages of this approach are reduced morbidity and hospital stay, shorter operating time, and avoidance of blood transfusions. However, this technique should be reserved until valuable insight is gained using the more conventional coronal approach.

Adult↗
PubMed1998

Studies in cranial suture biology: up-regulation of transforming growth factor-beta1 and basic fibroblast growth factor mRNA correlates with posterior frontal cranial suture fusion in the rat.

The mechanisms involved in normal cranial suture development and fusion as well as in the pathophysiology of craniosyostosis are not well understood. The purpose of this study was to investigate the expression of several cytokines--transforming growth factor-beta-1 (TGF-beta1), basic fibroblast growth factor (bFGF), and interleukin-6 (IL-6)--during cranial suture fusion. TGF-beta exists in three mammalian isoforms that are abundant in bone and stimulate calvarial bone formation when delivered locally. Other bone growth factors including basic fibroblast growth factor and the interleukins regulate bone growth and are mitogenic for bone marrow cells and osteoblasts. The involvement of growth factors in the pathophysiology of craniosynostosis is supported by recent genetics data linking fibroblast growth factor receptor mutations to syndromal craniosynostoses. In this experimental study, in situ hybridization was used to localize and quantify the gene expression of TGF-beta1, bFGF, and IL-6 during cranial suture fusion. In the Sprague-Dawley rat, the posterior frontal cranial suture normally undergoes fusion between 12 and 22 days of age, whereas all other cranial sutures remain patent. All in situ analyses of fusing posterior frontal sutures were compared with the patent, control, sagittal sutures. Posterior frontal and sagittal sutures, together with underlying dura, were harvested from rats at 8, 12, 16, and 35 days of postnatal life to analyze posterior frontal suture activity before, during, and after fusion. In situ hybridization was performed on frozen sections of these specimens using DNA probes specific for TGF-beta1, bFGF, and IL-6 mRNA. A negative control probe to IL-6 in the sense orientation was also used to validate the procedure. Cells expressing cytokine-specific mRNA were quantified (in cells positive per 10(-1) mm2) and analyzed using the unpaired Student's t test. Areas encompassing the fibrous suture and the surrounding bone plates were analyzed for cellular mRNA activity. IL-6 mRNA expression showed a minimal rise in the posterior frontal suture at days 12 and 16, with an average count of 10 and 6 cells per 10(-1) mm2, respectively. The sagittal suture remained negative for IL-6 mRNA at all time points. TGF-beta1 and bFGF analyses were most interesting, showing marked increases specifically in the posterior frontal suture during the time of active suture fusion. On postnatal day 8, a 1.5-fold increase in posterior frontal suture TGF-beta1 mRNA was found compared with sagittal sutures (p = 0.1890, unpaired Student's t test). This difference was increased 26-fold on day 12 in posterior frontal suture TGF-beta1 expression (p = 0.0005). By day 35, posterior frontal suture TGF-beta1 mRNA had nearly returned to prefusion levels, whereas TGF-beta1 mRNA levels in the sagittal suture remained low. A similar upregulation of bFGF mRNA, peaking at day 12, was observed in posterior frontal but not sagittal sutures (p = 0.0003). Furthermore, both TGF-beta1 and bFGF mRNA samples with intact dura showed an intense dural mRNA expression in the time preceding and during active posterior frontal suture fusion but not in sagittal tissues. Our data demonstrate that TGF-beta1 and bFGF mRNA are up-regulated in cranial suture fusion, possibly signaling in a paracrine fashion from dura to suture. TGF-beta1 and bFGF gene expression were dramatically increased both in and surrounding the actively fusing suture and followed the direction of fusion from endocranial to epicranial. These experimental data on bone growth factors support the recent human genetics data linking growth factor/fibroblast growth factor receptor deletions to syndromal craniosynostoses. The ultimate aim of these studies is to understand the underlying mechanisms regulating suture growth, development, and fusion so surgeons may one day manipulate the biology of premature cranial suture fusion.

Animals↗
PubMed1998

Studies in cranial suture biology: regional dura mater determines overlying suture biology.

The influence of dura mater on adjacent cranial sutures is significant. By better understanding the mechanisms of normal suture fusion and the role of the dura mater, it may be possible to delineate the events responsible for the premature suture fusion seen in craniosynostosis. In the Sprague-Dawley rat, the posterior frontal suture normally fuses between 12 and 20 days of postnatal life and has proved to be an excellent model to describe normal suture fusion. The purpose of this study was to document the critical role that the dura mater-suture complex may play on cranial suture biology. Forty Sprague-Dawley rats at 8 days of age were divided into two groups of 20 animals each. The control group (group A) had surgical disruption of the dura mater-calvarial interface. This was accomplished by elevating a strip of cranium inclusive of the posterior frontal and sagittal sutures and replacement of the cranial strip back to its anatomic position, all with the dura mater left intact. The experimental group (group B) had the same calvarial elevation (strip craniectomy), but the sutural anatomy/alignment was rotated 180 degrees. This rotation placed the posterior frontal suture into the sagittal suture's anatomic position and the sagittal suture into the posterior frontal suture's anatomic position. All of these procedures were accomplished by leaving the underlying dura mater intact. Animals were killed at 20, 30, 40, and 50 days (12, 22, 32, and 42 days postoperatively), and tissue sections were examined with hematoxylin and eosin staining. Group A (control) showed normal but delayed suture activity. The posterior frontal suture fused, and the sagittal suture remained patent. Fusion was delayed, not beginning before 20 days (12 days postoperative) and showing complete fusion between 30 and 40 days. Group B (180-degree calvarial rotation) demonstrated that the suture in the posterior frontal anatomic position (actual sagittal suture) fused between 20 and 40 days, whereas the suture in the sagittal anatomic position (actual posterior-frontal suture) remained patent throughout the study. This study demonstrates that the location of the dura mater-suture complex is important in determining either suture patency or closure in this model. Normal closure of the suture overlying the posterior frontal dura mater demonstrates that the dura mater itself, or forces derived in specific cranial locations, determines the overlying suture biology.

Animals↗
PubMed1998

Periorbital melanocytic lesions: excision and reconstruction in 40 patients.

The treatment of melanoma arising in the periorbital region is a difficult reconstructive problem. The abundance of vital structures in close proximity to one another makes the resection and subsequent reconstructive procedures extremely challenging. Reported here is experience with periorbital melanocytic lesions in 40 patients with the emphasis on the types of reconstruction performed. Forty patients with periorbital melanocytic lesions were treated between 1984 and 1995. The periorbital region was subdivided into five zones. These zones are the following: zone I, upper eyelid; zone II, lower eyelid; zone III, medial canthus; zone IV, lateral canthus; and zone V, contiguous structures. Ocular melanomas were not included in this study. The distribution of the lesions in our 40 patients was zone I (n = 1), zone II (n = 14), zone III (n = 1), zone IV (n = 9), and zone V (n = 31). The ages of the patients ranged from 3 to 84 years at the time of reconstruction, with an average age of 57 years. Resection and reconstruction were performed simultaneously in all patients. Thirty-six of the patients were reconstructed with one procedure, three patients required two procedures, and one patient required five procedures. The tumor type was superficial spreading melanoma in 15 patients, melanoma in situ in 17 patients, malignant spindle cell neoplasm in 2 patients, desmoplastic melanoma in 2 patients, amelanocytic melanoma in 1 patient, epithelioid melanoma in 1 patient, and atypical melanocytic nevus in 2 patients in which an early, evolving melanoma could not be excluded. Elective lymph node dissection was performed in four patients for intermediate thickness lesions (1.5 to 4.0 mm). The types of reconstructions performed included full-thickness skin grafts, upper lid myocutaneous flaps, cheek advancement flaps, cervicofacial flaps, inferiorly based nasolabial flaps, tarsoconjunctival flaps, frontalis muscle flaps, medial transposition Z-plasty, and primary closure. The resection of periorbital melanomas can be difficult because of the number of important anatomic structures in the region. The challenge to the surgeon in handling head and neck melanomas in general lies in the need to provide the best functional and aesthetic result while still resecting the primary lesion with the intent of effecting a cure. We present our series to demonstrate that the adequacy of margins of resection need not be compromised to facilitate reconstruction and that excellent results are obtainable with reconstructive procedures performed after adequate resections. Several different types of flaps and grafts can be used, with the indications varying depending on the location of the lesion and the extent of resection. The major reconstructive options will be reviewed in detail.

Adolescent↗
PubMed1998

Immunolocalization of basic fibroblast growth factor and fibroblast growth factor receptor-1 and receptor-2 in rat cranial sutures.

Craniosynostosis is a common disorder with an unknown etiology. Recent genetic mapping studies have demonstrated a strong linkage between several familial craniosynostotic syndromes and mutations in fibroblast growth factor receptor 1 (FGF-R1) and 2 (FGF-R2). The purpose of this experiment was to investigate by immunohistochemistry the protein production of these receptors as well as of their most prevalent ligand, basic fibroblast growth factor (bFGF), before, during, and after sutural fusion in rat cranial sutures. The posterior frontal (normally fuses between postnatal days 12 and 22) and sagittal (remains patent) sutures of embryonic day 20 and neonatal days 6, 12, 17, 22, and 62 (n = 3 per group) were harvested, fixed, and decalcified. Five-micrometer sections were stained with polyclonal antibodies against bFGF, FGF-R1, and FGF-R2, and patterns of immunohistochemical staining were assessed by independent reviewers. Our results indicate that increased bFGF production correlates temporally with suture fusion, with increased staining of the dura underneath the fusing suture prior to fusion followed by increased staining within osteoblasts and sutural cells during fusion. FGF-R1 and, to a lesser extent FGF-R2 immunostaining revealed a different pattern of localization with increased immunostaining within the patent sagittal suture at these time points. These results implicate bFGF in the regulation of sutural fusion and may imply autoregulatory mechanisms in fibroblast growth factor receptor expression.

Animals↗
PubMed1998

Rat mandibular distraction osteogenesis: Part I. Histologic and radiographic analysis.

The application of distraction osteogenesis to craniofacial surgery has altered the approach and treatment of congenital and acquired craniofacial defects. Although the histologic and ultrastructural changes associated with distraction osteogenesis have been described extensively, relatively little is known about the molecular regulation of this process. The elucidation of the molecular mechanisms of distraction osteogenesis has important clinical implications because it may facilitate the use of recombinant proteins or gene therapy to accelerate bone regeneration. Molecular analysis of distraction osteogenesis has been hindered by the use of large animal models in which only limited genetic information is available. In this study, a rat model of mandibular distraction osteogenesis is described. This report includes a pilot study (n = 50) to develop an appropriate distraction device and to determine the optimal placement of the osteotomy. The study subsequently included 80 animals, 35 of which were distracted at a rate of 0.25 mm per day for 6 days (1.5 mm total) and 35 that were distracted at a rate of 0.25 mm twice per day (3.0 mm total). These animals were killed at various time points (after latency and during the distraction and consolidation periods) and displayed histologic and radiographic findings of membranous bone distraction osteogenesis that were consistent with those in large ,animal and clinical models. In addition, five animals each were acutely lengthened 1.5 mm and 3.0 mm and demonstrated a fibrous nonunion. Furthermore, the utility of this model is demonstrated in the analysis of the molecular mechanisms of distraction osteogenesis by applying the polymerase chain reaction to total cellular RNA isolated from normal and distracted rat mandibles. In conclusion, it is believed that the rat model of distraction osteogenesis has significant advantages over traditional models, including decreased costs and facilitation of molecular analysis.

Animals↗
PubMed1998

Adverse outcomes following endoscopic repair of a fetal cleft lip using an ovine model.

OBJECTIVE: The purpose of this study was to determine if endoscopic techniques could be used to repair an epithelialized lip cleft with accuracy and with an outcome comparable to fetuses treated through an open hysterotomy. INTERVENTIONS AND RESULTS: In contrast to previous open fetal cleft lip repairs in the same model, none of the five fetuses reported here had a good aesthetic result. Although there was no evidence of scar histologically, the edges of the lip were poorly approximated. The epithelial lining and underlying dermis of the wound margins were notably inverted. The orbicularis oris muscle, which had been reapproximated, appeared thin and hypoplastic. Most of the vermilion elements were poorly aligned, and in one animal, there was a complete dehiscence of the repair. CONCLUSIONS: In a more representative model of cleft lip that is not an acute lip wound, in utero endoscopic suture repair of the ovine lip gave a poor result using current technology. Only a meticulously performed, multilayered, open repair of a cleft appears to give a good cosmetic and functional outcome. Further studies to improve the endoscopic repair as our technology advances are therefore warranted.

Animals↗
PubMed1998

Scarless healing. The fetal wound.

Fetal wounds heal without a scar early in gestation, and may hold the key to scarless repair. Several important concepts central to the fetal wound-healing response have been determined. The fetal fibroblast modulates the wound-healing response through collagen deposition, extracellular matrix deposition, and growth factor secretion. Fetal repair is both gestational-age and wound-size dependent, with a transition from scarless to scarring repair occurring during fetal life. Fetal fibroblasts manifest a decreased ability to induce dermal appendage formation from fetal epithelium at the same time that scarring in the fetus begins, suggesting that epithelial-mesenchymal interactions play an important role in scarless fetal repair. The fetal immune response during wound healing differs from the adult response, with a primarily mononuclear cell infiltrate and decreased activity and presence of polymorphonuclear leukocytes, whereas the cytokine profile of the fetal wound differs markedly from that of the adult wound. Patterning genes (homeobox genes) involved in organogenesis may prove integral to fetal healing, and are emerging as an active area of research. Once the biology of fetal wound healing is fully determined, attempts to manipulate the adult wound undoubtedly will progress rapidly, and scarless repair may become a clinical reality in children and adults.

Animals↗
PubMed1997

Wound size and gestational age modulate scar formation in fetal wound repair.

The early-gestation fetus heals incisional skin wounds rapidly and scarlessly. The morphology with which the fetus heals excisional skin wounds remains unclear. To characterize excisional fetal wound repair, and to determine whether there is a developmentally regulated wound-size threshold beyond which fetal skin heals with scar, the authors created excisional wounds in fetal lambs of varying gestational age. Time-mated pregnant ewes carrying 22 fetuses at 60 to 90 days' gestation (term, 145 days) underwent laparotomy and hysterotomy. An incisional wound and four circular, punch biopsy wounds of 2, 4, 6, and 10 mm in diameter were placed on the back of each fetal lamb and marked with India ink. The wounds were harvested at 14 days' postwounding and examined grossly and microscopically after serial sectioning and histological staining. Morphological features of all wounds were graded. By 14 days' postwounding all fetal wounds had healed completely. for lambs at each gestational age, increasing wound size was strongly associated with an increase in the frequency of scar. Also, as gestational age increased from 60 to 90 days' gestation the frequency of scarless repair decreased. By understanding the cellular and molecular processes that mediate scar formation with increasing wound size and advancing gestational age, the authors hope to gain further insight into the mechanisms of scarless fetal wound repair.

Animals↗
PubMed1997

Fibrotic healing of adult and late gestation fetal wounds correlates with increased hyaluronidase activity and removal of hyaluronan.

The lack of scarring and fibrosis in healing fetal skin wounds may relate to a prolonged presence of hyaluronan (HA). It has been suggested that fetal wounds may lack hyaluronidase, but the hyaluronidase levels in fetal wounds remain unknown. The size of HA influences its biological action, especially in relation to angiogenesis, which is also reduced in fetal wound healing. The present study determined the levels and size of HA, as well as hyaluronidase levels, in fetal and adult lamb wounds. Wire mesh cylinders, or polyvinyl acetate sponges, were placed subcutaneously in fetal lambs at 75, 100 or 120 days gestation. Wound fluid and wound tissue were harvested 3, 7 or 14 days later. Samples were digested with papain and both HA and hyaluronidase activity were determined in a competitive ELISA assay. Size distribution of HA was estimated using a Sephacryl S1000 column and fractions were collected for HA determination. Adult wound fluid HA remained low (4-5 micrograms/ml) over the 14 days. Fetal fluids were similar on day 3, but increased to 15-25 micrograms/ml by day 7. In 75/100-day wounds, HA remained elevated at 14 days, but in 120-day fluids decreased to levels similar to adult fluid. The HA in all fluids was polydisperse with a main peak at 200 kDa. Hyaluronidase levels were detected in all samples, reaching a peak 7 days post-wounding. In adult wound fluids hyaluronidase was much higher than the fetal wound fluids. These data suggest that lower hyaluronidase levels in fetal wounds may underlie the different pattern of HA deposition seen in fetal wounds.

Amniotic Fluid↗
PubMed1997

Bone morphogenetic protein promotes vascularization and osteoinduction in preformed hydroxyapatite in the rabbit.

Early reconstruction of large osseous defects in children is often delayed due to limited availability of autogenous bone graft donor sites. With the advent of growth factors, osteoinductive proteins, and delivery matrices, it is possible to fabricate new bone at extraskeletal sites. Due to their own blood supply, adequate bony volume, and decreased resorption, vascularized bone flaps have demonstrated greater success in restoring large bony defects compared with nonvascularized bone grafts. The purpose of this study is to prefabricate a vascularized bone flap in the immature-age rabbit using the auricularis anterior muscle as a muscle pedicle. Sixteen female New Zealand White rabbits, 2.0 to 2.5 kg, were divided into two groups. Group 1 contained 8 animals that had T-shaped, 10 x 6 x 4-mm hydroxyapatite (HA) implants combined with 100-microgram bovine-derived bone morphogenetic protein (BMP) placed supraperiosteally and fixed deep to the auricularis anterior muscle. Implants with HA alone were placed in the same animal and secured to the contralateral auricularis anterior muscle. Group 2 contained 8 animals that had HA/BMP placed subperiosteally and fixed deep to the auricularis anterior muscle, while implants with HA alone were secured in the same animal to the contralateral auricularis anterior muscle. In each group, 4 animals were sacrificed at 4 and 8 weeks. The animals underwent randomized bilateral carotid artery injection with micropaque barium suspension just prior to sacrifice to help maintain vascularity. At harvest the implants and surrounding muscle and cranium were removed en bloc. New bone formation in the HA implants was examined by using routine histology and scanning electron microscopic backscattering image (quantitative) analysis. Microradiographs were performed on representative specimens. At 4 weeks postimplantation, backscattering analysis in the subperiosteal HA/BMP showed a mean 17.1% bone ingrowth vs. 11.3% of HA alone (p < 0.05). Supraperiosteal HA/BMP showed a mean 12.9% bone ingrowth vs. 0% of HA alone (p < 0.05). At 8 weeks, backscatter analysis of supraperiosteal HA/BMP showed a mean 19.33% bone ingrowth vs. 0% of HA alone (p < 0.05). Subperiosteal HA/BMP showed a mean 22% bone ingrowth vs. 20.85% of HA alone. This was the only group that did not have statistically significant results. Implant histology demonstrated woven bone within the interstices of HA/BMP placed either supra- or subperiosteally. In the HA-alone implants placed supraperiosteally, fibrovascular ingrowth was seen without any evidence of bone formation. In the HA-alone implant placed subperiosteally, woven bone was seen at the calvarium-implant junction. Microradiographs also demonstrated vascularization and bone formation similar to that seen on scanning electron microscopy. BMP-treated specimens appeared to have slightly greater vascularity than the nontreated specimens. The greatest bone formation occurred with the HA/BMP implant placed subperiosteally in the immature rabbit. Furthermore, these results demonstrate the potential prefabrication of vascularized bone flaps as early as 4 to 8 weeks. The clinical advantage of HA permits the surgeon to design osseous flaps that are customized in shape, fill all contour defects, and have little resorptive properties. Such prefabricated bone with an axial blood supply may allow for ultimate transfer as a pedicle or free flap to reconstruct osseous defects in children.

Angiography↗
PubMed1997

Intracranial hypertension in a patient with craniofacial synostosis and patent sutures.

Craniosynostosis is often associated with restrictive cranial vault deformities, diminished intracranial volume, and intracranial hypertension. Advances in imaging techniques have provided a method of intracranial volume analysis that has demonstrated a more complicated relationship between craniofacial abnormalities and elevated intracranial pressures. Studies have confirmed a decrease in intracranial volume in the presence of craniosynostosis, but this association is not found in every patient. We report an unusual case of elevated intracranial pressure in a patient with the clinical stigmata of Crouzon's syndrome but with patent cranial vault sutures.

Cranial Sutures↗
PubMed1997

A new in utero model for lateral facial clefts.

The etiopathogenesis behind the formation of atypical craniofacial facial clefts remains unknown. To test the hypothesis that physical restricting forces such as amniotic bands can lead to the formation of these unusual clefts in the postorganogenesis period, we have modified a previously reported fetal lamb model of amniotic band syndrome to examine the effects of these bands on craniofacial development. Five 70-day gestation fetal lambs (term, 140 days) were exposed via a maternal hysterotomy. In each animal, an attempt was made to create a lateral craniofacial cleft by applying a 2-0 nylon suture as a constriction band to the growing face. The sutures were attached to either the zygomatic arch or the infraorbital rim externally and then looped circumferentially into the oral commissure. Each suture was positioned so as to create either a Tessier type 5 or a Tessier type 7 cleft. Four of five fetal lambs survived to term. Both types of lateral facial clefts were effectively produced using this model. In each group, the presence of an intraoral constriction band led to the formation of macrostomia, with an average 7.4-mm lateral displacement of the oral commissure. In addition to these soft tissue changes, each animal also had partial bony clefting (i.e., a bony groove) induced by the pressure of the restriction band across the growing facial skeleton. In the two lambs with the Tessier type 7 cleft, incomplete bony clefts developed across the zygomatic arch. In three animals with bands placed across the medial infraorbital rim, significant infraorbital and malar bony clefts formed similar to a classic Tessier type 5 facial cleft. No evidence of tissue necrosis, maceration, or ulceration was noted in any animal. These data present, for the first time, evidence that the constriction of craniofacial growth by external forces such as a swallowed amnionic band can lead to the development of lateral facial clefting involving both soft tissue and bony elements. These malformations are likely due to a combination of directly tethering normal tissue migration and an increase in local pressure, which produces cellular ischemia and apoptosis. Furthermore, our data demonstrate that these clefts can occur later in fetal development during a period of facial growth rather than during the period of primary facial morphogenesis.

Amniotic Band Syndrome↗
PubMed1997

Deep-plane cervicofacial "hike": anatomic basis with dog-ear blepharoplasty.

The temporal and cheek areas are particularly vulnerable to sun damage and therefore to skin cancers. Rotation-advancement flaps are used commonly in the reconstruction of these regions following resection of skin cancers. Such flaps usually are modifications of the Mustardé, cervicofacial, and Juri flaps. The drawbacks to these flaps relate to a random, unpredictable perfusion with skin loss at the distal flap tip, a vertically oriented dog-ear that predictably is located on the cheek, and the risk of gravitational and cicatricial forces acting on the lower eyelid causing ectropion. The deep-plane technique for raising cheek flaps, as has been described recently for use in rhytidectomy, allows the plastic surgeon to address both drawbacks of the standard cervicofacial flaps. The vertical "hike" deep-plane approach addresses both drawbacks of the rotation-advancement flaps by including better perfusion and superior mobility after release of restraining ligaments. We describe the anatomic rationale for the deep-plane dissection of the cheek in cadaver studies and present our clinical technique with a vertical "hike" cheek advancement with removal of the horizontally oriented dog-ear as in a blepharoplasty. This single-stage technique will be called the deep-plane "hike" flap. The vertically advanced flap must be slightly overcorrected by anchoring the flap to the periosteum just above the recipient defect. This deep fixation removes all tension from the skin and prevents ectropion. This single-stage reconstruction affords excellent cosmetic results without compromising any future reconstructive efforts.

Aged↗
PubMed1997

The inframammary extended circumflex scapular flap: an aesthetic improvement of the parascapular flap.

Parascapular free flaps traditionally have been designed obliquely across the back, corresponding to the descending branch of the circumflex scapular artery. The donor site of this workhorse flap has the drawback of a widened and frequently hypertrophic scar. In searching for aesthetic improvements in the donor site, we have progressively rotated the axis of this flap in an anterior direction. The end result of this modification is the flap we report here: the inframammary extended circumflex scapular flap. This flap has a longitudinal axis of rotation lying curvilinearly from the inframammary fold to the circumflex scapular artery within the triangular anatomic space. We have used this flap in 20 patients over the past 2 years. The vast majority of these cases were deepithelialized flaps with customized extensions of dorsal thoracic fascia to correct facial asymmetry. We feel that the inframammary extended circumflex scapular artery flap donor-site scar is well hidden within the inframammary fold, and that the unavoidable widening and hypertrophy of parascapular and scapular flap donor-site scars were minimized compared with traditional flap designs.

Adult↗
PubMed1997

Immunolocalization of transforming growth factor beta 1, beta 2, and beta 3 and insulin-like growth factor I in premature cranial suture fusion.

The etiology of craniosynostosis remains unknown. The beta group of transforming growth factors (TGF-beta) and insulin-like growth factors (IGF-I and IGF-II) are known to induce new bone formation and, when added exogenously, cause accelerated closure of calvarial defects. The possible roles of these bone growth factors in premature cranial suture fusion in humans have not been explored. We analyzed a total of 20 cranial suture biopsy samples (10 synostotic and 10 normal) from 10 infants with single-suture craniosynostosis undergoing cranial vault remodeling. Using isoform-specific antibodies for TGF-beta 1, -beta 2, and -beta 3 and IGF-I, we demonstrated immunoreactivity of these growth factors were present in human cranial sutures; the TGF-beta 2 isoform was the most intensely immunoreactive. Most importantly, the TGF-beta isoforms and IGF-I showed more intense immunoreactivity in the actively fusing craniosynostotic sutures compared with the control patent sutures. Specifically, the TGF-beta isoforms and IGF-I were intensely localized in the osteoblasts synthesizing new bone at the suture margin. It is noteworthy that although the patent sutures were less immunoreactive for TGF-beta isoforms than fused sutures, there was a distinct pattern of the TGF-beta 3 isoform that was immunolocalized to the margin of the normal patent sutures. This suggests a possible role for TGF-beta 3 in maintaining cranial suture patency. The increased immunoreactivity of both TGF-beta 2 and IGF-I in the actively fusing sutures compared with the patent control sutures indicates that these growth factors may play a role in the biology underlying premature suture closure. To our knowledge, this is the first study showing the presence of TGF-beta 1, -beta 2, and -beta 3 and IGF-I in prematurely fusing human cranial sutures. In the future, manipulating the local expression of these growth factors at the suture site may enable plastic surgeons to modulate premature suture fusion.

Child, Preschool↗