The role of the cranial base in facial growth: experimental craniofacial synostosis in the rabbit.

Craniofacial synostosis designates premature fusion in sutures of the cranial vault (calvarium). When craniofacial synostosis is associated with a syndrome (e.g., Apert, Crouzon), premature fusion of the cranial base has been postulated to occur as well. This study was designed to determine whether the primary growth disturbance in craniofacial synostosis is located at the cranial base (i.e., spheno-occipital synchondrosis) or the calvarial vault (i.e., coronal and sagittal sutures) or both. Sixty newborn New Zealand White rabbits were randomly assigned to six groups: (I) calvarial control, (II) cranial base control, (III) cranial base immobilization, (IV) coronal suture immobilization, (V) coronal and sagittal suture immobilization, and (VI) cranial base and coronal and sagittal suture immobilization. An anterior cervical microsurgical approach to the cranial base was used, while cranial vault sutures were exposed through a bicoronal scalp incision. All sutures were fused by periosteal abrasion and application of methyl cyanoacrylate. Cephalograms were taken at 30, 60, and 90 days postoperatively to assess craniofacial growth. Linear and angular measurements of facial, calvarial, and basicranial growth were subjected to multivariate analysis. Analysis indicated that (1) craniofacial length was shortened most significantly by cranial base fusion, (2) cranial base fusion and cranial vault fusion had an additive effect on craniofacial length restriction, (3) the anterior cranial base was significantly shortened by cranial base and cranial vault fusion (p < 0.05), (4) the posterior cranial base was shortened by cranial base fusion only (p < 0.05), and (5) cranial base fusion alone significantly flattened the cranial base angle (p < 0.05), whereas cranial vault fusion alone did not. These results suggest that cranial base fusion alone may account for many dysmorphic features seen in craniofacial synostosis. This model is consistent with the findings of other investigators and confirms both a primary directive and translational role of the cranial base in craniofacial growth.

Functional reconstruction for severe postburn microstomia.

A man with severe burn microstomia refractory to traditional management (Z release, skin grafting, splinting, bilateral commissuroplasty, and extensive physical therapy) is presented. Successful functional microstomia reconstruction was achieved with a three-stage approach consisting of the following: (1) lip, commissure, and cheek reconstruction with bilateral temporalis muscle transfers; (2) free flap neck and lower lip contracture release; and (3) vestibuloplasty with a stented full-thickness skin graft.

Anterior cervical microsurgical approach to the cranial base in the rabbit: technical note.

Current trends in research on craniofacial syndromes have led to enhanced interest in the cranial base as a contributory factor in the development of normal and abnormal midfacial structure. Indeed, attention has focused upon one particular growth plate in the posterior cranial base, the spheno-occipital synchondrosis, since it has been shown that alterations in this structure are associated with profound changes in craniofacial growth. In this report we describe a surgical approach to the cranial base of the rabbit that is safe, simple and reliable. It is applicable to neonatal as well as adult rabbits.

Facial skeletal growth after timed soft-tissue undermining.

This study was designed to answer the following questions: (1) Does aggressive bilateral soft-tissue undermining of the nasomaxillary complex in an immature animal without an iatrogenically produced cleft lip significantly inhibit growth? (2) If so, is the early timing of this undermining crucial? Fifty New Zealand White rabbits were used in this study, and bilateral buccal sulcus incisions with extensive nasomaxillary supraperiosteal undermining were performed in the experimental groups. There were five groups: (1) control, (2) undermining at 3 to 4 days, (3) undermining at 7 to 10 days, (4) undermining at 18 to 21 days, and (5) undermining at 50 to 56 days. The animals were sacrificed at 6 months of age, and direct osteometric measurements were made. Results demonstrated that a significantly retruded, constricted, and vertically shortened maxilla was produced as a direct result of bilateral nasomaxillary soft-tissue undermining alone regardless of the timing.