PubMed Health⌕ Search

Biomedical subjects

Joseph G McCarthy

Publications and source records attributed to Joseph G McCarthy.

At least 19 recordsLinked to original sources
PubMed2006

Long-term stability and growth following unilateral mandibular distraction in growing children with craniofacial microsomia.

BACKGROUND: The purpose of this study was to evaluate long-term mandibular skeletal stability and growth following unilateral mandibular distraction in growing children. METHODS: This retrospective longitudinal study of 12 consecutive patients with unilateral craniofacial microsomia who underwent mandibular distraction had a range of 5 years of postdistraction follow-up; five patients were followed for 10 years. Records included clinical photographs, dental study models, lateral and posteroanterior cephalograms, and panoramic radiographs obtained before distraction, at the time of device removal, and 1, 5, and 10 years after distraction. The mean patient age at the time of distraction was 48 months. The device was activated an average of 21.7 mm at the rate of 1 mm per day. The mean latency period was 6.1 days, and the mean consolidation period was 60.6 days. Fifty-two parameters were examined at each of the five time intervals. RESULTS: On average, the ramal length (condylion to gonion) increased 13.04 mm in the distracted rami. At 1 year after distraction, this dimension decreased by 3.46 mm. At 5 and 10 years after distraction, the average condylion-gonion dimension increased by 3.83 and 4 mm, respectively, with an average growth rate of 0.87 mm per year; during the same period, the unaffected ramus grew 1.15 mm per year. CONCLUSIONS: The distraction technique does not eliminate the inherent growth potential of the affected mandibular side. Facial asymmetry is significantly improved after distraction, and despite mild relapse observed during the first year, surgical correction is stable in the later years of follow-up.

Cephalometry↗
PubMed2006

Distraction osteogenesis in a patient with juvenile arthritis.

We present a 26-year-old patient with juvenile-onset arthritis, Alagille's syndrome, micrognathia, and progressive sleep apnea. Despite the presence of significant temporomandibular joint pathology, mandibular distraction was indicated to correct life-threatening sleep apnea. Before distraction, the patient had only 10 mm of maximal interincisal opening and bilateral temporomandibular joint symptomatology. After distraction, the patient's sleep apnea resolved. There was slight improvement in her maximal incisal opening (12 mm) with neither exacerbation nor improvement of her temporomandibular joint symptomatology.

Adult↗
PubMed2006

Delayed degradation in a resorbable plating system.

Resorbable plating systems are used extensively for craniofacial reconstruction, particularly in children. The systems provide rigid fixation while potentially minimizing the long-term drawbacks of permanent plating systems such as plate "migration," bone growth restriction, and imaging artifact. However, the need for active plate resorption represents both the strength and weakness of these fixation systems. We present four patients who underwent cranial vault remodeling using a resorbable plating system, following which the plates were palpable and observable for at least 2 years postoperatively. All required surgical removal. On gross inspection, the plates had been replaced by an encapsulated spongy material containing yellow, grainy, cloudy liquid. The bone underlying the plates was depressed and irregular in contour when compared with the adjacent bone. Microscopic studies showed a giant cell foreign-body reaction with crystalline material present in the cell vacuoles.

Absorbable Implants↗
PubMed2005

Stem cells and distraction osteogenesis: endothelial progenitor cells home to the ischemic generate in activation and consolidation.

BACKGROUND: Ischemia is a limiting factor during distraction osteogenesis. The authors sought to determine the extent of ischemia in the distraction zone and whether endothelial progenitor cells home to the distraction zone and participate in local vasculogenesis. METHODS: Laser Doppler imaging was used to assess the extent of blood flow in the distraction zone in gradually distracted, immediately distracted, and osteotomized rat mandibles during activation and consolidation. Animals (n = 50; 25 rats with unilateral gradual distraction and contralateral osteotomy as an internal control, and 25 rats with unilateral immediate distraction) were examined on postoperative days 4, 6, and 8 of activation, and after 1 and 2 weeks of consolidation. Endothelial progenitor cells isolated from human peripheral blood were labeled with fluorescent DiI dye, and 0.5 x 10 cells were injected intra-arterially under direct vision into each carotid artery at the start of activation in nude rats (n = 18) that then underwent the distraction protocol outlined above. RESULTS: Doppler flow analysis demonstrated relative ischemia during the activation period in the distraction osteogenesis group and increased blood flow in the osteotomized control group as compared with flow in a normal hemimandible [normal, 1 (standardized); distraction osteogenesis, 0.58 +/- 0.05; control, 2.58 +/- 0.21; p < 0.05 for both results]. We observed a significantly increased endothelial progenitor cell population at the generate site versus controls at midactivation and at 1 and 2 weeks of consolidation [25 +/- 1.9 versus 1 +/- 0.3 DiI-positive cells per high-power field (p < 0.05), 124 +/- 21 versus 8 +/- 4 DiI-positive cells per high-power field (p < 0.05), and 106 +/- 18 versus 9 +/- 3 DiI-positive cells per high-power field (p < 0.05), respectively]. CONCLUSIONS: These data suggest that the distraction zone becomes relatively ischemic during activation and that endothelial progenitor cells home to the ischemic generate site during the activation phase and remain during the consolidation phase. Selective expansion of these stem cells may be useful in overcoming ischemic limitations of distraction osteogenesis. Moreover, their homing capability may be used to effect site-specific transgene delivery to the generate.

Animals↗
PubMed2005

The effect of an early Le Fort III surgery on permanent molar eruption.

The purpose of this retrospective study was to evaluate the extent to which an early Le Fort III osteotomy affects the position and eruption of the permanent maxillary first and second molars. To test the null hypothesis that there are no changes in eruption patterns, 31 patients diagnosed with craniosynostoses (13 with Crouzon's syndrome, nine with Apert's syndrome, eight with Pfeiffer's syndrome, and one with Carpenter's syndrome) with a mean age at the time of surgery of 5.3 +/- 1.3 years were studied. All patients underwent a Le Fort III osteotomy performed by a single surgeon to correct the anatomical deformity for functional and psychosocial reasons. Eighteen patients with craniosynostoses who had not been operated on (11 with Crouzon's syndrome, four with Apert's syndrome, and three with Pfeiffer's syndrome) served as controls; they had a mean age of 21.2 +/- 9.5 years. First and second molar positions and eruption patterns were assessed separately on panoramic radiographs by three observers. For the patients who underwent surgery, long-term evaluation showed that although 79 percent of all first molars erupted compared with 100 percent for the control group (p < 0.001), only 18 percent of all second permanent molars erupted compared with 89 percent for the control group (p < 0.0001). The authors conclude that in a significant minority of cases, early Le Fort III osteotomy affects first molar eruption, whereas the probability of second molar eruption is significantly decreased in the majority of cases. Therefore, Le Fort III osteotomy sites should be positioned distal to the second molar tooth buds. If this is not possible, patients, parents, and dental professionals should be made aware of these early postosteotomy sequelae so that later treatment planning can be enhanced.

Adult↗
PubMed2005

Understanding the molecular basis of Apert syndrome.

Apert syndrome, first described in 1906, is one of the most severe of the craniosynostosis syndromes and is further characterized by midface hypoplasia, syndactyly, and other visceral abnormalities. Affected individuals generally require lifelong management by a multidisciplinary team of health care specialists. Apert syndrome results almost exclusively from one or the other of two point mutations in fibroblast growth factor receptor 2. Tremendous scientific advances have been made recently in understanding the molecular basis for Apert syndrome through clinical genetic, biochemical, and structural approaches. In this review, the authors provide the clinician with a basic overview of these findings and their therapeutic implications.

Acrocephalosyndactylia↗
PubMed2004

Reconstruction of a large mandibular defect utilizing temporary zygomatic-ramal fixation and bilateral Risdon incisions.

Ameloblastoma is a benign, invasive, odontogenic tumor of the jaws that predominantly affects the mandible. Despite the benign nature of these lesions, there is a high rate of local recurrence after curettage, which usually requires resection. The traditional surgical approach for resection of ameloblastomas, via either mandibulotomy or mandibulectomy, has been through lower lip-splitting incisions, which are associated with significant functional and esthetic sequelae. A case is presented here in which less invasive Risdon and intraoral degloving incisions were used in combination with temporary zygomatic-ramal fixation to maintain occlusion after resection of a large mandibular ameloblastoma. The bilateral Risdon approach provided wide access to the mandible, allowing an angle-to-angle resection to be performed. This approach also provided adequate exposure for an osteocutaneous fibula free flap reconstruction to be performed, with 100% flap survival. At 1 year of follow-up, there were minimal functional and esthetic defects. This approach represents a less invasive alternative that provides access to the mandible for curative resection of benign tumors with minimal postoperative sequelae.

Adult↗
PubMed2004

Volumetric assessment of the distracted human mandible.

The mandibles of five patients who underwent unilateral or bilateral distraction osteogenesis were analyzed using computed tomography scans. The mandibles were reconstructed in three dimensions using General Electric computed tomography software. The total volume of each hemimandible was determined before and after distraction and compared. The mandibles were then segmented at 1-cm intervals, and the volumes of the segments were determined. The volumes of the mandibular segments before and after distraction were compared to determine the distribution of new bone through the mandible and the quantity of bone generated by distraction. The distracted hemimandibles increased in total volume by an average of 19.9% (statistically significant by the Student paired t test; P < 0.0001), whereas the nondistracted hemimandibles increased in total volume by an average of 5.2%. The segmental volumes of the distracted mandible were of similar or greater volume when compared to the preoperative mandibular segments. In addition, the distribution of regenerate bone mirrored the physiological distribution of the preoperative mandibular bone. This study indicates that distraction not only creates new bone but distributes that bone through the remodeled mandible in an anatomical pattern similar to that of the preoperative bone.

Bone Density↗
PubMed2004

Predicting decannulation outcomes after distraction osteogenesis for syndromic micrognathia.

OBJECTIVES: To characterize the airway anatomy by upper endoscopy in children with syndromal mandibular hypoplasia and to determine whether predistraction endoscopy is predictive of the likelihood of successful outcomes after mandibular distraction. STUDY DESIGN: Retrospective chart review. METHODS: Assessment of the upper airway by subsites was qualitatively extrapolated into a devised 4-point scale. Upper airways were characterized and evaluated in patients on the basis of decannulation outcomes after distraction. RESULTS: Of the 20 patients, 12 were decannulated, and 6 remain tracheostomy dependent. The average compiled preoperative airway obstruction scores in decannulated patients (2.25) compared with those who failed decannulation (2.36) was not statistically significant (P =.291). A significant change after distraction was noted only at the levels of the oropharynx and supraglottis (P <.001). The average airway scores at these subsites in decannulated patients improved from a mean of 3.46 to 2.17 (P =.002). In patients who failed decannulation, the pre- and postdistraction scores also improved from 3.92 to 2.50 (P =.026). Analysis of the average postdistraction airway scores in decannulated patients (2.17) compared with failures (2.5) failed to reveal a significant difference (P =.375), suggesting that some patients remain tracheostomy dependent despite adequate mandibular expansion. Preoperative airway scores in the two groups were statistically equivocal and, therefore, not predictive of the likelihood of decannulation. CONCLUSIONS: Preoperative airway endoscopy alone is not predictive of the likelihood of successful decannulation after distraction osteogenesis. Comparison of the airway patency after distraction revealed statistically equivocal airway caliber, suggesting that some children fail to advance to decannulation despite adequate mandibular distraction.

Bronchoscopy↗
PubMed2004

Removal of mandibular tooth follicles before distraction osteogenesis.

Distraction osteogenesis is an innovative technique that has transformed the treatment of craniofacial malformations in young children. Bone generation obviates the need for graft material, which is in short supply in young patients, thus making possible surgical procedures on the craniofacial skeleton in young children. Sufficient mandibular volume is required for the osteotomy and placement of the device screws and/or pins. To have adequate bone stock and to facilitate distraction, the authors preoperatively examined all patients radiographically and selected those with tooth follicles that precluded successful osteotomy and pin placement for planned mandibular distraction. This report is of the first 13 children, aged 9 months to 6 years, who underwent predistraction enucleation. The osteotomy and device placement were performed successfully at least 4 months after enucleation. The described procedure has minimal morbidity and has resulted in successful subsequent distraction. The advantages, disadvantages, and cost-benefit issues are discussed.

Bone Nails↗
PubMed2004

Bone morphogenic protein-2 gene therapy for mandibular distraction osteogenesis.

Distraction osteogenesis (DO) requires a long consolidation period and has a low but real failure rate. Bone morphogenic proteins (BMPs) accelerate bone deposition in fractures and critical-sized bone defects, but their effects on mandibular DO are unknown. We investigated the effect of local delivery of adenovirus containing the gene for BMP-2 (Adbmp-2) on mandibular DO in a rat model. Rats (n = 54) were distracted to 3 mm over 6 days. At the start of consolidation (POD 10), Adbmp-2 or adenovirus containing the lacZgene (AdlacZ) was injected directly into the distraction zone. After 1, 2, and 4 weeks of consolidation, mandibles were evaluated for amount of bone deposition. Adbmp-2-treated specimens demonstrated an increased amount of new bone formation by radiographic, histologic, and histomorphometric analysis. This study demonstrates that local, adenovirally-mediated delivery of BMP-2 can increase bone deposition during DO, potentially shortening consolidation and enhancing DO in poorly healing mandibles, such as occurs postirradiation.

Adenoviridae↗
PubMed2003

The temporal sequence of periosteal attachment after elevation.

This study investigated the adherence of periosteum to bone after elevation to document the temporal sequence of healing at the periosteal/bone interface. There has been a lack of consensus among surgeons as to the time required for healing at this interface; some believe that the healing achieves significant strength in a few days, whereas others believe that the periosteum does not adhere to the bone for many weeks. The aim of this study was to document the time course for healing, completeness of the reattachment, and structural characteristics of the union of bone and periosteum. To test the hypothesis, scalp flaps were elevated in a subperiosteal plane and were reattached in 40 adult guinea pigs and controls. The individual groups were studied at 3, 6, 12, 30, and 90 days postoperatively. Postmortem study consisted of analysis of the mechanical and histologic findings. Strength of adherence was documented by measuring the force required for reverse avulsion of the flaps with an Instron Mini 44 tensiometer. The specimens were also submitted for electron microscopic examination. The mean tension recorded in the plateau phase of avulsion of the flaps was as follows: controls, 78 g; experimental at 3 and 6 days, not applicable (weak adherence not permitting exposure for reverse avulsion); 12 days, 39 g (p = 0.0001); 30 days, 58 g (p = 0.0012), and 90 days, 63 g (p = 0.0229). There was a significant difference between all groups and the controls. Electron microscopic study showed collagen deposition at the bone periosteal interface, which became progressively more organized in the groups studied at 30 and 90 days, with decreasing amounts of inflammation and inflammatory cells. This study demonstrated that healing at the bone/periosteal interface progresses at a rate consistent with healing of most other wounds, dispelling many widespread beliefs that the adherence at this interface was accelerated. The temporal sequence of healing at the periosteal bone interface should be considered in the various procedures in which periosteal flaps are elevated. For example, there is clinical relevance in subperiosteal brow lift procedures, in which the periosteum should be reattached by a fixation technique that will remain stable for a minimum of 30 days to allow adequate adherence between the bone and periosteum at the postoperative elevated brow position.

Animals↗
PubMed2003

Volumetric change of the medial pterygoid following distraction osteogenesis of the mandible: an example of the associated soft-tissue changes.

Mandibular distraction osteogenesis lengthens not only the affected skeleton but also the associated muscles of mastication. The purpose of this study was to determine medial pterygoid volume before and after distraction by using computed tomography. Using computed tomographic scans, the volume of the medial pterygoid muscle was determined before and after mandibular distraction in six pediatric patients. In four unilateral distraction patients (average age, 65 months), the average increase of the medial pterygoid muscle on the distracted side of the mandible was 29 percent, and on the contralateral nondistracted side, 10 percent. The average increase in medial pterygoid muscle volume in two bilateral distraction patients (each aged 8 months) was 75 percent. Results of this study demonstrate that distraction osteogenesis of the human mandible not only lengthens deficient bone, but it also increases the volume of the attached musculature.

Child↗
PubMed2003

Molding of the regenerate in mandibular distraction: clinical experience.

Initial clinical experience with distraction osteogenesis has demonstrated the risk of developing postdistraction malocclusion that requires secondary orthodontic correction. In addition, optimal mandibular form is not always achieved. Both animal studies and preliminary clinical investigations have suggested that the regenerate can be successfully "molded" during active mandibular distraction. The authors have applied this concept clinically to obtain a more desirable occlusal relationship in a group of mandibular distraction patients. Eleven patients are described in whom angulation of the distraction device or intermaxillary/interdental elastics were employed to mold the regenerate. Two representative case studies are provided to illustrate the principles. When using elastic traction to close an anterior open bite, care must be taken that extrusion of individual teeth is minimized by distributing the force over the entire dental arch, especially the basilar portions of the jaws. The authors demonstrate that molding of the regenerate can be successfully accomplished not only during device activation but also early in the consolidation period. The outer limit of the time window in which molding is effective remains to be defined.

Adolescent↗
PubMed2003

Cephalometric analysis of the consolidation phase following bilateral pediatric mandibular distraction.

OBJECTIVE: The goal of the consolidation phase of mandible distraction is to maintain the improvement in maxillomandibular form and relationship while the generated tissue ossifies. During this period, external deforming forces can act on the healing generated bone. The purpose of this study was to describe the potential cephalometric changes that occur following pediatric bilateral mandibular distraction using external devices. DESIGN: Retrospective lateral superimposition cephalometric analyses. PARTICIPANTS: Thirty-five cases of pediatric mandible distraction were reviewed. Seven of these cases were included in the study after exclusion criteria were applied. These cases represented a group with severe congenital dysmorphology and a mean device activation of 26.5 mm. MAIN OUTCOME MEASURES: Changes in pogonion position, symphyseal plane rotation, mandible length, and mandible length relative to maxillary length during the 18 to 36 days of activation, the eight weeks of consolidation, and the 1-year period following removal of the distraction device were measured. RESULTS: All patients demonstrated variable changes in position of the mandible during the consolidation phase. The most common were retrusion of pogonion, a decrease in mandible length, and a clockwise rotation of the symphyseal plane. In some cases the changes that occurred during consolidation were greater than those that occurred on 1-year follow-up. CONCLUSIONS: The consolidation phase of distraction osteogenesis is a dynamic phase and should not be assumed to be static. Multicenter use of this cephalometric technique would help to identify potential risk factors associated with postactivation changes.

Cephalometry↗