Court B. Cutting

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.

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.

Presurgical columellar elongation and primary retrograde nasal reconstruction in one-stage bilateral cleft lip and nose repair

&NA; We present a new combined approach to primary bilateral cleft lip, nose, and alveolus repair using presurgical nasoalveolar molding combined with a one‐stage lip, nose, and alveolus repair. Presurgical alveolar molding is used to bring the protruding premaxilla back into proper alignment with the lateral segments in the maxillary arch. Presurgical nasal molding produces tissue expansion of the short columella and nasal lining. A coordinated surgical approach involves a one‐stage repair of the lip, nose, and alveolus. The nasal repair uses a retrograde approach in which the prolabial flap and columella are reflected over the nasal dorsum by continuing the dissection behind the prolabium up the membranous septum and over the septal angle. Tissues are dissected out from between the tip cartilages, and the domes are sutured together in the midline. This method joins a new class of bilateral cleft repairs that place the primary emphasis on correction of the deformity of the nasal tip cartilages.

Long-Term Effects of Nasoalveolar Molding on Three-Dimensional Nasal Shape in Unilateral Clefts

OBJECTIVE This objective of this study was to determine the effect of presurgical nasoalveolar molding on long-term nasal shape in complete unilateral clefts. DESIGN The study was retrospective, and the subjects were chosen at random. Nasal casts of the subjects were scanned in three dimensions. Each nose was best fit to its mirror image, and a numerical asymmetry score was determined. SETTING All patients were treated at the Institute of Reconstructive Plastic Surgery, NYU Medical Center, New York, New York. PATIENTS The study subjects (n = 10) were selected from a group that had undergone presurgical nasal molding in conjunction with alveolar molding. The control subjects (n = 10) were selected from a group that had undergone presurgical alveolar molding alone. INTERVENTIONS All subjects underwent presurgical orthopedic treatment until the age of approximately 4 months at which time the primary surgery was performed. MAIN OUTCOME MEASURE The nasal shape following nasal molding should be more symmetrical than if molding had not been done. RESULTS The mean asymmetry index for the nasoalveolar molding group was 0.74, and the control group was 1.21. This difference was statistically significant (p < .05). CONCLUSIONS Presurgical nasoalveolar molding significantly increases the symmetry of the nose. The increase in symmetry is maintained long term into early childhood. The limitations of this study include (1) asymmetry alone is not an adequate shape result in most situations, (2) the children evaluated in this study were not fully grown, and (3) the control group was not age matched.

Twenty-year experience with early surgery for craniosynostosis : II. The craniofacial synostosis syndromes and pansynostosis-Results and Unsolved Problems

As the second of a two-part series, 76 patients with pansynostosis and craniofacial synostosis syndromes were retrospectively analyzed. Diagnoses included pansynostosis (7), craniofrontonasal dysplasia (8), and Apert (24), Crouzon (15), and Pfeiffer (15) syndromes. All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 6.1 months). Twenty-eight patients (36.8 percent) required a secondary cranial vault operation (mean age 28.4 months). Additionally, a major tertiary procedure was necessary in 5 patients to deal with persistent unacceptable craniofacial form. To address the associated finding of midface hypoplasia, 64.8 percent (n = 35) of patients underwent Le Fort III midface advancement or had that procedure recommended for them. The remainder were awaiting appropriate age for this reconstruction. The more extensive pathologic involvement of the pansynostosis and craniofacial syndrome group is illustrated. As compared with the isolated craniofacial synostosis group previously reported, the incidence of major secondary procedures (36.8 versus 13.5 percent), perioperative complications (11.3 versus 5.0 percent), follow-up complications (44.7 versus 7.7 percent), hydrocephalus (42.1 versus 3.9 percent), shunt placement (22.4 versus 1.0 percent), and seizures (11.8 versus 2.9 percent) was significantly increased. Complex problems including those of increased intracranial pressure, airway obstruction, and recurrent turricephaly or cranial vault maldevelopment are repeatedly encountered. In addition, that early fronto-orbital advancement-cranial vault remodeling failed to promote midface development and hypoplasia of this region is almost a consistent finding in the craniofacial syndromic group. The average length of postoperative follow-up was 6 years. According to the classification of Whitaker et al., which assesses surgical results, 73.7 percent of patients were considered to have at least satisfactory craniofacial form (category I–II) at latest evaluation. An algorithmic approach to the treatment of all patients with craniosynostosis is presented utilizing early surgical intervention as the key element.

Blood supply of the upper craniofacial skeleton: the search for composite calvarial bone flaps.

This study investigated the blood supply of the upper craniofacial skeleton by injection studies. The major supply to the calvaria is provided by the middle meningeal artery and its branches. This vessel is difficult for the plastic surgeon to exploit in composite bone-flap design. The majority of the outer surface of the craniofacial skeleton is supplied by tiny perforators from the overlying periosteum. The vascular interconnections within the periosteum are poorly developed. For this reason, the galea and the overlying vascular network (derived from the superficial temporal, occipital, supraorbital, and supratrochlear vessels) should be left broadly attached to the bone when transferring a vascularized calvarial bone flap. Dissection of the scalp away from this vascular network should be carried out just below the hair follicles. By observing these principles, vascularized calvarial bone can be transferred on the superficial temporal, deep temporal, supraorbital, supratrochlear, or occipital vessels. Details of the use of each are discussed.

Comparison of residual osseous mass between vascularized and nonvascularized onlay bone transfers.

Composite flaps containing vascularized frontal bone were transferred on muscle pedicles in immature rabbits. Vascular continuity was maintained on one side and interrupted on the other. Bone weights at 16 weeks following transfer were compared with those of unoperated controls. The conventional bone graft demonstrated significant reduction in osseous mass. The vascularized bone maintained its mass compared with unoperated controls. Vascularized bone transfer appears to be the preferred surgical technique whenever possible.

An experimental neurovascular island skin flap for the study of the delay phenomenon.

We present an experimental neurovascular island skin flap. It is a consistent, reproducible model which produces a definite pattern of surviving skin flap area versus skin flap necrosis. There is a constant, anatomically definable nerve and vascular supply to the flap. This model permits independent experimental manipulation of the neural, arterial, and venous supply to the skin. It is useful, therefore, for the study of the vascular mechanisms of the skin microcirculation. We also demonstrated that increased flap survival can be produced by a delay involving denervation alone (leaving the vascular supply intact) or by devascularization alone (leaving the nerve supply intact). We conclude that both the adrenergic denervation and the ischemia contribute to the production of the delay phenomenon. We suggest that sustained vasodilation--vascular smooth muscle relaxation--is the vascular mechanism that accounts for the delay phenomenon.

Nasoalveolar molding improves long-term nasal symmetry in complete unilateral cleft lip-cleft palate patients.

Background: Nasoalveolar molding was developed to improve dentoalveolar, septal, and lower lateral cartilage position before cleft lip repair. Previous studies have documented the long-term maintenance of columella length and nasal dome form and projection. The purpose of the present study was to determine the effect of presurgical nasoalveolar molding on long-term unilateral complete cleft nasal symmetry. Methods: A retrospective review of 25 consecutively presenting nonsyndromic complete unilateral cleft lip–cleft palate patients was conducted. Fifteen patients were treated with presurgical nasoalveolar molding for 3 months before surgical correction, and 10 patients were treated by surgical correction alone. The average age at the time of follow-up was 9 years. Four nasal anthropometric distances and two angular relationships were measured to assess nasal symmetry. Results: All six measurements demonstrated a greater degree of nasal symmetry in nasoalveolar molding patients compared with the patients treated with surgery alone. Five symmetry measurements were significantly more symmetric in the nasoalveolar molding patients and one measurement demonstrated a nonsignificant but greater degree of symmetry compared with the patients treated with surgery alone. Conclusions: The data demonstrate that the lower lateral and septal cartilages are more symmetric in the nasoalveolar molding patients compared with the surgery-alone patients. Furthermore, the improved symmetry observed in nasoalveolar molding–treated noses during the time of the primary surgery is maintained at 9 years of age.