The "Eve" procedure: the transfer of vascularized seventh rib, fascia, cartilage, and serratus muscle to reconstruct difficult defects.

Very few microvascular units entertain the possibility of simultaneous vascularized transfer of bone, cartilage, muscle, and gliding fascia. In exceptionally complex conditions with loss of an essential joint, adjacent bone and functional muscle, reconstruction of all these structures at once may be necessary. At the same time, gliding tissue is often required to cover tendons. Reconstruction in one sitting prevents formation of dense scar tissue due to multiple interventions. Additionally, less bone resorption is seen if vascularized bone is used. Therefore, a more undisturbed tissue composition at the end is guaranteed. Moreover, rapid rehabilitation of moving function is possible with improvement in the final result. Finally, morbidity is lowered by using a single donor site, and costs are minimalized. We present four unique cases in which the seventh rib including the costochondral junction with overlying serratus muscle, branches of the thoracicus longus nerve, and adjacent fascia have been transferred as a microvascular unit to reconstruct two severely damaged hands and two other complex injuries. In analogy with the Bible story of the creation of "the woman," it is called the "Eve" procedure. The vascularized rib was used to reconstruct a first and fourth metacarpal bone, the ascending ramus of the mandible, and the clavicle. The rib cartilage was sculptured in four cases to reconstruct an articular surface. The serratus muscle served as coverage and filling for lost tissues. It also was used as a soft bed for facial nerve repair. In two cases muscle reinnervation was performed. The fascia provided gliding tissue surrounding reconstructed tendons or articular surfaces. In all cases a high degree of function was obtained with a good cosmesis. Rehabilitation was uneventful, and no reinterventions have been necessary. Donor-site morbidity was low. Therefore, this flap proved to be successful in complex injuries where bone, cartilage, muscle, and gliding tissue were needed simultaneously. Dynamic reconstruction was attempted in two cases and was successful in one.

The effect of unilateral partial facial paralysis and muscle ablation on craniofacial growth and development: an experimental study in the rabbit.

The effect of unilateral partial facial nerve ablation and unilateral partial midface muscle ablation on craniofacial growth and development was investigated. New Zealand White rabbits (12 days old) were randomly assigned to three experimental groups: control group, to study normal craniofacial growth and development (n = 15); nerve ablation group, surgically induced unilateral paralysis of the buccal branches of the facial nerve (n = 15); and muscle ablation group, surgical unilateral ablation of the facial muscles innervated by the buccal branches of the facial nerve (n = 12). All animals were operated on at the age of 12 days; follow-up evaluations were performed at the ages of 2 months and 6 months. The age of 2 months represents the endpoint of the prepubertal craniofacial growth and development. At the age of 6 months, the animals are fully grown; therefore, the time period between 2 and 6 months is regarded as the pubertal growth period. Computerized dorsoventral roentgencephalometric (measurement of distances and angles) and computer tomographic (three-dimensional volumetric measurements) investigations were performed at both ages. Additional dry skull measurements were performed to determine more precisely the bone segments involved in the craniofacial growth alterations studied. The obtained results indicated the following. Unilateral partial facial paralysis involving the midface resulted in growth alterations analogous to those seen after unilateral total facial paralysis. The growth alterations were not to be seen as a growth restriction (reduction in bony volume) but as growth misdirections (alterations in shape). Major growth alterations were present in those regions closely related to the facial musculature, namely the nasal, maxillary, and premaxillary regions, resulting in a snout deviation toward the operated side. The growth alterations occurred during prepuberty and remained rather stable during puberty. Morphologic signs of muscle denervation were related to the craniofacial growth disturbances. The growth alterations after unilateral partial facial paralysis were mainly biomechanically induced, as they were analogous to those observed after unilateral midfacial muscle ablation. The fact that after unilateral midfacial muscle ablation at the age of 6 months the severity of the alterations had increased was attributed to the scar formation inherent to the surgical procedure.

The effect of muscle transplantation after unilateral partial facial paralysis on craniofacial growth and development: relationship between muscle and nerve histomorphometric findings.

Muscle transplantation has become an indispensable tool to restore the smile in patients with long-standing or congenital facial paralysis. However, little is known of the effect of this surgical intervention on craniofacial growth and development or of the adaptation of the transplant to its recipient site under circumstances of growth. The present study investigates these phenomena in the rabbit model. Twelve-day-old New Zealand White rabbits were randomly assigned to three experimental groups. The control group was used to study normal craniofacial growth and development (n = 15). In the nerve ablation group, unilateral paralysis of the buccal branches of the facial nerve was surgically induced (n = 15). In the transplant group, the surgically induced unilateral paralysis of the buccal branches was immediately followed by a neuromuscular graft (n = 12). All animals were operated on at the age of 12 days, and follow-up evaluations were performed at the ages of 2 months and 6 months. Computerized dorsoventral roentgencephalometric and computed tomography investigations were performed at both ages. Nerve and muscle histomorphometric measurements were performed at the age of 6 months to relate the quality of nerve and muscle regeneration to the growth parameters. The roentgencephalometric measurements revealed that analogous disturbed parameters were present in the nerve ablation and the transplant groups. However, in the transplant group, an additional significant effect of time between 2 and 6 months was seen for some parameters. This resulted in significant differences between the nerve ablation and transplant groups at 6 months for these parameters. Computed tomography measurements showed no significant differences in maxillary or mandibular volume in the transplant group compared with the control or nerve ablation groups. However, a significantly diminished increase in bone volume existed in the transplant group for the time period between 2 and 6 months in comparison with the control and nerve ablation groups. Muscle histomorphometric findings revealed a significant change in muscle fiber composition in the graft compared with the normal latissimus dorsi muscle; this was due to a major decrease in type IIB fibers, with an increase in type I and type IIA fibers. Compared with the normal zygomaticoauricular muscle, the amount of type I fibers was significantly increased. No fiber atrophy was found. Macroscopically, the transplanted muscle failed to increase its length during growth. Nerve histomorphometric findings demonstrated a normal amount of nerve fibers; however, they had significantly decreased diameters and reduced myelin areas. The nerve histomorphometric parameters were related to the muscle histomorphometric findings, which in turn were related to craniofacial growth disturbances. These findings suggested that the main growth differences between the transplant group and the control group may have been due to altered nerve function influencing muscle function. Scar tissue formation and the development of more intense muscle activity later are suggested as the causes of the additional effect of time between 2 and 6 months for the several parameters in the transplant group. Reasons for the failure of complete conversion of the graft to a fast muscle and the failure of the transplant to elongate during growth are discussed.

Maxillofacial growth after neck burn injury at a young age: an experimental study in the rabbit.

An experimental model was designed to define alterations in the normal mandibular growth process under the influence of postburn neck contractures. Additionally, this craniofacial growth model was used to compare two early treatment modalities of neck burns in their capability to minimize contracture and hence allow for normal mandibular growth and development. Growth implies increase in size as well as change in shape and position. These three aspects of growth were defined accordingly to Björk as rotations. The intramatrix rotation expresses the change in mandibular shape, and the matrix rotation expresses the change in mandibular position relative to surrounding structures. The total rotation expresses both, and together with the measurement of the mandibular length, they represent the increase in mandibular size. Thirty-two 7-week-old rabbits were divided at random in four groups of eight rabbits each and randomized for selection for the 14 operation days defined as t = 0: Group A: controls to define normal mandibular growth Group B: untreated third-degree neck burns Group C: third-degree neck burns treated by a full-thickness skin graft Group D: third-degree neck burns treated by a myocutaneous flap All animals underwent placement of two bone markers in the maxilla. With biweekly intervals, standardized lateral skull roentgenographs were taken until the rabbits reached the age of 21 weeks. In this time period, major growth accelerations including the pubertal growth spurt took place. By the use of 13 reference points and 7 reference lines, rotations and distances were calculated. Statistical analysis of the data was performed. The results show that the normal mandibular length was unaffected in all groups. There were no statistically significant changes in matrix, intramatrix, and total rotations of the mandible and the maxilla. There was a statistically significant difference in the displacement of the mandibular reference point between all groups, suggesting a variable degree of normal backward skull rotation, namely, due to group B. Explanations to be considered concerning the fact that the only minor differences were found in group B: 1. Drawbacks of the animal model: differences in skin texture, postnatal mandibular growth, and head position compared with those of humans. 2. Other functional adaptation mechanisms such as changes in head position, which are recruited at first in adapting to disturbances of homeostasis, were not measured. Soft-tissue compensation probably has overcome major bony deformations. Nevertheless, some drawbacks of the model can be viewed as ideal concerning treatment of neck burns.(ABSTRACT TRUNCATED AT 250 WORDS)