The effects of continuous passive motion on the temporomandibular joint after surgery. Part II. Appliance improvement, normal subject evaluation, pilot clinical trial.

An earlier publication (Part I) described the development of an appliance for delivering continuous passive motion (CPM) to the temporomandibular joints after surgery. In this article, we describe further design changes in the CPM appliance and evaluate its acceptability and safety in normal subjects. The therapeutic effectiveness is described in a pilot study of patients' responses to CPM after temporomandibular joint surgery. The study will be continued in a formal prospective clinical trial comparing the efficacy of postsurgical CPM with that obtained from ultrasonic and other forms of physiotherapy.

The effects of continuous passive motion on the temporomandibular joint after surgery. Part I. Appliance design and fabrication.

The application of continuous passive motion (CPM) to synovial joints immediately after orthopedic surgery stimulates the regeneration of articular tissue, eliminates adhesions, prevents joint stiffness, reduces pain, and is well tolerated by patients. This article reviews the development of CPM in animal studies and its subsequent clinical applications to patients after orthopedic surgery. It seems likely that CPM applied to the temporomandibular joint after surgery would result in similar advantages to patients. We identify the criteria for the function, patient acceptability, and safety of a CPM appliance to be used on the temporomandibular joint. The first prototype is described and redesigned in a second model that meets the necessary criteria for testing on patients.

The cloverleaf skull anomaly: an anatomic and histologic study of two specimens.

Two neonatal human specimens exhibiting the cloverleaf skull anomaly were studied in detail using gross, radiographic and histologic techniques. Both specimens exhibited premature fusion of the right and left coronal sutures, right and left lambdoidal sutures, and midsagittal sutures. Although the specimens grossly exhibited a similar trilobed appearance of the craniofacial complex, the interrelationship and spatial orientation of their respective articular and skeletal components differed markedly. The development of the cranial base in one specimen appeared normal, while in the other specimen, the synchondroses between the supraoccipital, exoccipital, basioccipital, basisphenoid, and presphenoid bones were prematurely obliterated histologically, resulting in a substantial decrease in the length of the cranial floor. The latter specimen also exhibited micromelic shortening of the limbs with abnormal chondrocyte proliferation and maturation at the epiphyseal growth plates. The alterations in the size and shape of the calvarial bones subsequent to premature sutural synostosis were more severe in the specimen with premature closure of the cranial base synchondroses. The striking differences observed in the anatomic and histologic analysis of the specimens demonstrated tha the cloverleaf skull malformation must be etiologically and pathogenetically heterogeneous.

Cranial synostosis and intra-uterine compression: a developmental study of human sutures.

The following hypothetical statements can be made. 1) Increased intra-uterine compression of the human cranium during the third trimester appears to produce sagittal synostosis by irreversibly altering the still immature sutural tissue that separates the parietal bones. 2) Intra-uterine compression does not cause facial sutures to fuse because they are physically shielded by the larger neurocranium and their ligaments are sufficiently mature to survive a chronic compressive force. 3) Postnatal compression of cranial and facial sutures normally does not result in bony fusion because their vascularized, differentiated, mature ligaments are capable of repair and regeneration.

Experimentally induced ankylosis and facial asymmetry in the macaque monkey.

Six Macaca nemestrina were used for induction of ankylosis by different methods. One TMJ capsule was either (a) mechanically damaged, (b) injected with sodium morrhuate, or (c) injected with a strain of Staphylococcus aureus. The other capsule served as a control. Facial asymmetry of varying degrees was evident from dry-skull preparations and histologically. Sodium morrhuate caused the least degree of alteration; mechanical damage, the most. The effects of Staph. aureus injection into the TMJ seemed to depend upon the length of time elapsed since injection. In one animal there was no change at autopsy after two injections several weeks apart, once on each side; in the other, the capsule injected initially showed no change at autopsy, whereas that injected several weeks prior to autopsy was considerably altered. Induction of ankylosis was achieved with varying degrees of success, causing differing degrees of facial asymmetry.

Teratogenic effects of retinoic acid in pigtail monkeys (Macaca nemestrina). II. Craniofacial features.

The teratogenic effects of retinoic acid, the alcohol-soluble acid form of vitamin A, on the craniofacial complex of 11 macaque (Macaca nemestrina) whose mothers had received the compound from days 20 to 44 are described. The fetuses ranged in gestational age from 81 to 185 days and exhibited features of the so-called retinoic acid syndrome (RAS). The syndrome includes both craniofacial defects and postcranial anomalies of the musculoskeletal and urogenital systems. The craniofacial anomalies were described with reference to gross external appearance and radiographic observations. The most frequent findings were cleft palate, malformed ears, hypertelorism, exophthalmos, hypoplasia of the bone of the mid-face and mandible, a curvature of the inferior border of the mandible, retrognathia, and distortion of the cranium. Lateral cephalograms on nine animals of the RAS sample were measured using six linear dimensions which define the cranial base, face height, palatal length, and mandibular length. The measurements were plotted relative to normal curves which describe growth of the dimensions through the macaque fetal period. For their age, the abnormal animals were small in the craniofacial region. The same measurements were then plotted relative to the size of the fetus, to investigate the possibility of a differential response of the various craniofacial areas to the teratogen. Mandibular length and anterior cranial base were the most reduced dimensions, followed by anterior and posterior face height, with palatal length the least affected. Comparison of the features of the RAS syndrome in the macaque fetus with those reported for various human mandibulofacial dysostosis syndromes yields similarities, but there are enough differences to indicate that the syndromes are not identical in the two species. The utility of the approach used, wherein several craniofacial dimensions of the abnormal are assessed relative to normal growth curves and relative to body size, is emphasized.

Condylar trauma and facial asymmetry: an experimental study.

Surgical intracapsular concylar fractures were initiated on young monkeys followed by prolonged intermaxillary fixation in an effort to create facial asymmetry and induce temporomandibular joint ankylosis. Implanted head positioners and metallic bone markers were used to document developing facial asymmetry in all animals. Vertical opening capabilities were fully recovered and the procedures had no discernible functional impact. Slight limitation of movement persisted only in the translation of the damaged condyles. It was concluded that trauma followed by long term fixation had no effect in promoting ankylosis or significant limitation of jaw movement. It is suggested that when considering the role of trauma in the aetiology of ankylosis, attention be given to those factors which may complicate an existing trauma.

Subtotal neonatal calvariectomy. A radiographic and histological evaluation of calvarial and sutural redevelopment in rabbits.

A subtotal calvariectomy was performed on rabbits between 10 and14 days of age. The animals were allowed to grow and were then sacrificed serially so that the sutural and skeletal redevelopment could be analyzed through a combination of gross, radiographic, and histological techniques. The results indicate that calvarial regeneration is a progressive process with a definite pattern and rate of development. During the regenerative process, bone was deposited both at the surgical margin and as islands within the srugical defect. The eventual approximation of these areas of ossification produced multiple fibrous articulations. The majority of these articulations were obliterated by bone union, except for the midsagittal, coronal, and metopic sutures, which were re-established in their appropriate antomical positions. The maintenance of dural integrity during the surgical phase and the regeneration and establishment of pericranial continuity during the postoperative period were believed to be important in the re-establishment of normal sutural and skeletal architecture.

A histologic study of age changes in the adult human periodontal joint (ligament).

This study evaluated the histological age changes in 80 periodontal joints from 24 human cadavers ranging in age from 20 to 90 years. The limitations of such a descriptive study were reviewed to prevent overextrapolation of the findings to whole populations. In the young speciments, the bone surface of the tooth socket was smooth and regular with the insertion of Sharpey's fibers evenly distributed in the woven bone. Interstitial lamellae were found between secondary osteons in the alveolar bone. Copious periodontal fibers passed around small vascularized interstitial spaces to insert evenly into the cementum as Sharpey's fibers. Numerous cells, probably fibroblasts, were present within and between the fiber bundles. Like the bone surface, the cemental surface was smooth and regular. Both cellular and acellular cementum were present. Cemental splits were found both intracementally and at the cemento-dentinal junction. In the older specimens, the periodontal surface of the alveolar bone was jagged and uneven with Sharpey's fibers inserting irregularly into the woven bone. Subjectively an increased amount of internal remodeling was seen in the periodontal bone. A relative decrease in both suspensory fibers and cellular content was noted in the periodontal ligaments of the older specimens. Large vascularized interstitial spaces encroached upon areas formerly occupied by periodontal fibers and bone. Fat cells also were observed replacing the suspensory fibers. The cementum showed an irregular surface into which Sharpey's fibers were unevenly inserted. Both cellular and acellular cementum were present, and cemental splits were seen with the same frequency as in the young specimens. There was a tendency for greater cemental apposition, particularly in the apical region of the tooth. In many respects the aging periodontal joint showed atrophic and degenerative changes similar to those in cranio-facial sutures. However, these changes did not include either bony ankylosis or osteoporosis related to increasing age. In summary, the periodontal joints of the younger specimens were well organized while those of the older specimens showed a more irregular structure and a decrease in fiber and cellular content. Intermediate changes were seen in the intermediate age groups.

Research on control of craniofacial morphogenesis: an NIDR State-of-the-Art Workshop.

To assess the wide clinical ramifications of control of craniofacial morphogenesis, a State-of-the-Art Workshop was conducted by the National Institute of Dental Research at the initiative of Richard L. Christiansen, Chief of the Craniofacial Anomalies Program. In conjunction with the authors listed above, the format for the workshop was developed and participants were selected. The workshop was designed to provide an in-depth review of present knowledge and to identify future goals and directions for research on guiding, altering, and thus controlling growth and development of the cranofacial skeleton. The agenda for discussion ranged from molecular biology to clinical arts such as orthopedics and surgery. It was evident during the workshop that the mechanisms and procedures for controlling craniofacial morphogenesis must be derived from many biologic, physical, and clinical fields of knowledge. It is hoped that there will evolve an interdisciplinary clinical art which is aimed at preventing and correcting craniofacial deformities. Substantial biologic information has already been accumulated on the craniofacial skeleton. The clinical art of correcting malocclusion through mechanical forces is now applicable to the entire skull. The outstanding technical accomplishments of radical surgery in the correction of congenital craniofacial anomalies show that the needed surgical skills are now available. When these resources are combined, an area of knowledge and a clinical discipline which might be called "orthocephalics" is already identifiable. The workshop was held at the National Institutes of Health in Bethesda, Maryland, on Feb. 12 and 13, 1974. The ideas exchanged were integrated and summarized by the planning committee to produce this report.

Teratogenic effects of retinoic acid in pigtail monkeys (Macaca nemestrina). I. General features.

Daily oral administration of 10 mg/kg retinoic acid to pregnant Macaca nemestrina monkeys on days 20 to 44 resulted in a high frequency of craniofacial and musculoskeletal malformations. Craniofacial defects including cleft palate and anomalies of the prinna were common as were ectrodactyly, kyphosis, and muscular-joint contractures. Transposition of the great vessels of the heart occurred in one animal and polycystic kidney and associated urogenital anomalies in another. Shorter treatment periods with similar or higher dosages were not teratogenic and were less fetocidal. Although only relatively long treatment courses were teratogenic, the defects that resulted were morphologically similar to those induced with retinoic acid or other vitamin A compounds in other animal orders.