Joseph G. McCarthy

Lengthening the Human Mandible by Gradual Distraction

Lengthening of the mandible by gradual distraction was performed on four young patients (average age 78 months). The amount of mandibular bone lengthening ranged from 18 to 24 mm; one patient with Nagers syndrome underwent bilateral mandibular expansion. Following the period of expansion, the patients were maintained in external fixation for an average of 9 weeks to allow ossification. The patients were followed for a minimum of 11 months to a maximum of 20 months with clinical and dental examinations as well as photographic and radiographic documentation. The technique holds promise for early reconstruction of craniofacial skeletal defects without the need for bone grafts, blood transfusion, or intermaxillary fixation.

Membranous Bone Lengthening: A Serial Histological Study

Bone lengthening using the process of corticotomy and gradual distraction of callus is applicable to the membranous bone of the canine mandible. In this study the precursors to bone formation, in the area between the distracted bone edges, are analyzed in an attempt to determine the mechanism of bone formation. Ten mongrel dogs 5 months of age were studied. A unilateral, periosteal-preserving angular corticotomy was performed, and an external bone-lengthening device was fixed to the mandible. After 10 days of external fixation, the mandible was lengthened 1 ml per day for 20 days and then held in external fixation for 8 weeks. The dogs were killed for histological and microradiographic study at 10 and 20 days of distraction, and at 14, 28, and 56 days after the completion of distraction. It was observed that the gap between the distracted bone edges is first occupied by fibrous tissue. As distraction proceeds, the fibrous tissue becomes longitudinally oriented in the direction of distraction. Early bone formation advances along the fibrous tissue, starting from the cut bone ends. Eventually the area is converted to mature cortical bone. Bone is formed predominantly by intramembranous ossification. This mechanism is similar to that of bone formation during long bone lengthening.

Three-dimensional computer-assisted design of craniofacial surgical procedures : optimization and interaction with cephalometric and CT-based models

A computer program is described which aids the clinician in planning craniofacial surgical procedures. It operates on a three-dimensional landmark data base derived by combining posteroanterior and lateral cephalograins from the patient and from the Bolton normative standards. A three-dimensional surgical simulation program based on computerized tomographic (CT) data is also described which can be linked to the cephalometrically based program. After the clinician has selected the number and type of osteotomies to be performed on the patient, an automated optimization program computes the postoperative positions of these fragments which best fit the appropriate normal cephalometric form. The clinician then interactively modifies the design to account for such variables as bone-graft resorption, relapse tendency, occlusal disparities, and the condition of the overlying soft-tissue matrix. Osteotomy movement specifications are easily transferred between the CT-based and the cephalometrically based surgical simulation programs. This allows the automated positioning step to be performed on the cephalometrically based model while the interactive step is performed using the superior image provided by the CT-based model.

The spectrum of calvarial bone grafting: introduction of the vascularized calvarial bone flap.

Two techniques of calvarial bone grafting (split-thickness and single-table) are reviewed. A new vascularized bone flap based on the temporal vasculature is presented. The indications and relative advantages of each are discussed. The calvarial bone flap is emphasized and strongly recommended. Since the flap is vascularized and contains membranous bone, it is particularly suited for bone grafting in clinically unfavorable recipient sites, such as scarred or irradiated beds or the hypoplastic zygomatic-maxillary complex in the Treacher Collins syndrome.

Twenty-year experience with early surgery for craniosynostosis. I: Isolated craniofacial synostosis : results and unsolved problems

Early surgery for isolated craniosynostosis is designed to improve morphology, to prevent functional disturbances, and equally important, to enhance the psychosocial development of the child. As the first of a two-part series, 104 patients with isolated craniofacial synostosis were retrospectively analyzed. Diagnoses included bilateral coronal (10), unilateral coronal (57), metopic (29), and sagittal synostosis (8). All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 8.1 months). Thirteen percent of patients (14) required a secondary cranial vault operation (mean age 22.6 months) to address residual deficits in craniofacial form. Perioperative complications were minimal (5.0 percent), and there was no mortality. Average length of postoperative follow-up was 46.0 months. By the classification of Whitaker et al., which assesses surgical results, 87.5 percent of patients were considered to have at least satisfactory craniofacial form (category I–II) at latest evaluation. Overall rates of hydrocephalus, shunt placement, and seizures (3.8, 1.0, and 2.9 percent, respectively) were low. Among the isolated craniosynostoses, unilateral coronal synostosis/plagiocephaly poses the most complex problems, including vertical orbital dystopia, nasal tip deviation, and residual craniofacial asymmetry; there is also a wide spectrum of findings and growth patterns in this subgroup.

Three-Dimensional Computer-Aided Design of Craniofacial Surgical Procedures

Computer graphics promises to provide a tool for the precise planning of craniofacial procedures and the rigorous evaluation of results. There are three essential ingredients: three-dimensional imaging, simulation of surgical osteotomies, and quantitation of the residual deformity.

Extramammary Paget's disease.

Extramammary Pagets disease is an in situ skin and mucosal carcinoma frequently associated with and probably arising in a subjacent or regionally proximate carcinoma. Microscopic spread of tumor cells almost always extends beyond clinically apparent disease. Surgical treatment requires carefully planned, systematic excision under precise histologic control. An ideal treatment method remains to be developed. Inadequate excision usually results in recurrences that can be successfully treated by reexcision. Associated invasive carcinomas occur frequently, and mortality is high in these patients.

Airway management in children with major craniofacial anomalies

Objectives: Delineation of clinical characteristics affecting the airway in a cohort of craniofacially deformed children. What factors differ between patients requiring and those not requiring surgical airway intervention? What factors predispose to the need for tracheotomy? When can decannulation be expected if tracheotomy is required? What interventions aid decannulation? Study Design: Five‐year retrospective chart review at tertiary center. Methods: Two hundred fifty‐one patients met the following entry criteria: enrollment in the New York University Institute of Reconstructive and Plastic Surgerys Craniofacial Clinic and admission to Tisch Hospital in Manhattan for surgery from 1990 to 1994. Hospital, clinic, and departmental office records were reviewed. All patients had major craniofacial bony anomalies and underwent administration of general anesthesia at least once. Results: Nearly 20% of all children required tracheotomy (47/251). Craniofacial synostosis patients (Crouzon, Pfeiffer, or Apert syndrome) had the highest rate of tracheotomy (48% [28/59]). Mandibulofacial dysostoses patients (Treacher Collins or Nager syndrome) had the next highest rate (41% [28/59]). Patients with oculo‐auriculo‐vertebral sequence were less likely to undergo tracheotomy (22% [9/41]). Children with craniosynostosis rarely required a surgical airway, unless there was marked associated facial dysmorphism (1% [1/72]). The duration of cannulation was related to the age at tracheotomy in a bimodal distribution. Generally, tracheotomies required before age 4 years remained for several years, whereas those placed after age 4 were removed after several weeks. The presence of a cleft palate correlated with reduced risk for tracheotomy, but the presence of a ventriculoperitoneal shunt correlated with an increased risk for tracheotomy. Procedures selectively used to improve the airway included midface advancement, mandibular expansion, tonsillectomy and adenoidectomy, uvulopalatopharyngoplasty, anterior tongue reduction, and endoscopic tracheal granuloma excision. Conclusions: The likelihood for surgical airway management is related to specific craniofacial diagnosis. The length of tracheal cannulation is greatest for infants and young children who manifest severe airway compromise, often because of nasal obstruction in combination with other anatomic factors. Early tracheotomy is advocated for these patients to promote optimal growth and development. Choanal atresia is often misdiagnosed in these infants; nasal obstruction is actually secondary to midface retrusion. Staged surgical interventions can allow eventual successful decannulation in nearly all cases of craniofacial syndromes.

Rat Mandibular Distraction Osteogenesis: II. Molecular Analysis of Transforming Growth Factor Beta-1 and Osteocalcin Gene Expression

Distraction osteogenesis is a powerful technique capable of generating viable osseous tissue by the gradual separation of osteotomized bone edges. Although the histologic and ultrastructural changes associated with this process have been extensively delineated, the molecular events governing these changes remain essentially unknown. We have devised a rat model of mandibular distraction osteogenesis that facilitates molecular analysis of this process. Such information has significant clinical implications because it may enable targeted therapeutic manipulations designed to accelerate osseous regeneration. In this study, we have evaluated the expression of transforming growth factor beta-1, a major regulator of osteogenesis during endochondral bone formation and development, and osteocalcin, an abundant noncollagenous extracellular matrix protein implicated in the regulation of mineralization and bone turnover. The right hemimandible of 36 adult male rats was osteotomized, and a customized distraction device was applied. Animals were allowed to recover and, after a 3-day latency period, were distracted at a rate of 0.25 mm twice daily for 6 days followed by a 2- or 4-week consolidation period. Distraction regenerate was harvested after the latency period, days 2, 4, or 6 of distraction, and after 2 or 4 weeks of consolidation and processed for Northern analysis (n = 4 at each time point) and immunohistochemical localization of TGF-beta1 (n = 2 at each time point). Six sham-operated animals (i.e., skin incision without osteotomy) were also killed (immediately postoperatively), and the mandibles were harvested and prepared in a similar fashion. Equal loading and transfer of RNA for Northern analysis was ensured by stripping and probing membranes with a probe against GAPDH (a housekeeping gene). Our results demonstrate that the spatial and temporal patterns of TGF-beta1 mRNA expression and protein production coincide with osteoblast migration, differentiation, and extracellular matrix synthesis. In addition, we demonstrate that TGF-beta1 production may be an important regulator of vasculogenesis during mandibular distraction osteogenesis. Finally, we have shown that osteocalcin gene expression coincides temporally with mineralization during rat mandibular distraction osteogenesis.

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

&NA; 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 matercalvarial 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 sutures anatomic position and the sagittal suture into the posterior frontal sutures 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 (180degree 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. (Plast. Reconstr. Surg. 101: 1441, 1998.)