Remodeling of the temporomandibular joint following mandibular distraction osteogenesis in the transverse dimension.

Transverse mandibular distraction osteogenesis involves moving the osteotomized segments of the mandible in either a varus or valgus direction. This maneuver allows for widening of the bigonial distance or for a lateral shift of an asymmetric mandibular midline. During this process, a significant amount of torque is placed on the mandibular condyles, because they act as the pivot point for the mandibular translation. Although standard linear distraction osteogenesis induces transient, reversible changes in the temporomandibular joint, it is not known what effect the varus and valgus stresses of transverse distraction have on the temporomandibular joint. We therefore designed a study to document the temporomandibular joint changes following various degrees of transverse distraction. Bilateral transverse mandibular distraction was performed on 10 adult, female mongrel dogs using an external, multiplanar mandibular distraction device. The distraction protocol was as follows: (1) complete osteotomy at the angle of the mandible, (2) 5-day latency period, (3) distraction rate of 1 mm/day, (4) rhythm of one turn per day, (5) linear activation 16 to 30 mm bilaterally, and (6) 8-week consolidation period. A variety of varus and valgus distraction vectors were applied to the mandible only after 10 mm of initial linear distraction had been achieved. Posteroanterior and lateral cephalograms were performed throughout the entire process. Pre-distraction and post-consolidation computed tomographic scans were also performed. Changes in mandibular conformation, axis of rotation, temporomandibular joint structure, and glenoid fossa changes were directly assessed by evaluating the postmortem craniofacial skeleton. The findings were compared with those of normal, age-matched mongrel dog skulls. Significant remodeling changes were observed in the temporomandibular joints of all animals involved in the study. The mandibular condyles demonstrated varying degrees of flattening and erosion at all contact points with the craniofacial skeleton. In some cases, the condyle became part of the distraction regenerate process and was hypertrophied in all dimensions. The condyles were frequently displaced out of the glenoid fossa, particularly on the side in the direction of varus distraction. When the latter occurred, a new fossa was created on the undersurface of the zygomatic arch. Varying degrees of mandibular rotation in the sagittal plane were also observed, which led to abnormal torquing of the condyles in the coronal plane, depending on whether the axis of rotation occurred primarily around the condyle or around the distraction regenerate zone.In conclusion, transverse mandibular distraction is an effective means of producing a varus or valgus shift in the gonion relative to the midsagittal plane. However, unlike linear or angular mandibular distraction, transverse distraction has a multitude of nontransient effects on the temporomandibular joint. Therefore it must be emphasized that in clinical practice, transverse distraction should be used cautiously. One must also be aware that such a maneuver in distraction can have negative effects on the temporomandibular joint.

Endoscopic foreheadplasty: a histologic comparison of periosteal refixation after endoscopic versus bicoronal lift.

Endoscopic brow lift techniques using temporary fixation rely on rapid readherence of the periosteum to calvarial bone. Little is known about the histologic events that occur during the early postoperative period after these procedures. An animal study was designed to compare and contrast periosteal fixation to bone and unelevated periosteum, with endoscopic and bicoronal brow lift techniques. One method of temporary fixation is the use of absorbable (polylactic/polyglycolic acid copolymer) LactoSorb screws; a histologic analysis of implanted LactoSorb screws was also performed. Sixteen rabbits underwent brow lifts; eight underwent endoscopic brow lift and fixation with LactoSorb screws without skin excision, and another eight underwent traditional bicoronal brow lift with skin excision and closure under tension. Animals were killed 1, 2, 6, and 12 weeks after the procedures were performed to evaluate the interaction of periosteum and bone and the normal, unelevated periosteum/calvarium interface at a site distant from the operative area. Histologic specimens were examined for the degree of apposition of periosteum to bone and for any fibrous or bony reaction at this interface. Histologic analysis showed various degrees of periosteal fibrosis and fixation to calvarial bone. After an initial phase of minimal periosteal adherence and moderate inflammation, the periosteum became progressively more adherent to bone in both groups, with no significant differences between treatment groups in rates of fixation. Fixation required at least 6 weeks. LactoSorb screws were surrounded by an area of mild inflammation and were progressively hydrolyzed and digested. Periosteal fixation increases over time for bicoronal and endoscopic brow lifts with minimal differences between the two techniques. With this animal model, periosteal adherence to calvarium requires at least 6 weeks with complete adherence by 12 weeks. In addition, the use of absorbable fixation screws seems to be both effective and well tolerated. The histologic changes associated with periosteal healing observed in this study suggest that permanent or semipermanent fixation may improve the accuracy and early postoperative maintenance of forehead advancement.

Chin augmentation.

The primary goal of facial aesthetic surgery is to restore, enhance, and rejuvenate the aging face to a more youthful appearance, achieving balance and harmony. The mental area must be addressed in order to have a complete synthesis of the face. The concept of augmenting the mental area with implants has evolved so significantly that it now stands by itself as an important procedure. Various autogenous implants for chin augmentation have been in use for over 100 years but have complications. The advent of synthetic materials has given rise to various types of alloplastic implants: Gore-Tex, Medpor, Supramid, Silastic, and Mersilene. No one implant is perfect for every face. This article overviews several alloplastic implants--their advantages, disadvantages, and complications, in addition to the different techniques of preparing and delivering the implants.

Reconstruction of a neocondyle using transport distraction osteogenesis.

The process of slow bone expansion by distraction osteogenesis in conjunction with functional remodeling can also be used for the reconstruction of a neomandible and neocondyle. This is the technique of transport distraction osteogenesis. A transport disc is surgically created adjacent to the area of a discontinuity defect, and the transport disc is advanced by the process of distraction osteogenesis, using the Ilizarov principles. The mandible therefore acts as the bony template for reconstruction such that the neomandible created from the distraction process has the same size and shape as the native mandible covered by gingiva. This allows for enhanced prosthetic reconstruction. A reverse-L osteotomy of the ramus can also be performed to create a transport disc to reconstruct a neocondyle. Because the leading edge of the transport disc becomes enveloped by a fibrocartilagenous cap, the ramal transport disc can be moved superiorly to create a new articulation. Patients are encouraged to open and close their mouths during the distraction process, such that the transport disc remodels to form a neocondyle. This technique was successfully used to treat patients with degenerative joint disease, condylar resorption, and bony ankylosis.

Distraction osteogenesis for the reconstruction of the temporomandibular joint.

Distraction osteogenesis is the technique of slow bone expansion across an osteotomy site. Most commonly used for orthopedic lengthening of the extremities, it is now being applied to the craniofacial skeleton, including treatment of facial asymmetries, micrognathias and mandibular discontinuity defects. The technique can also be applied for the reconstruction of a neo-condyle. Transport distraction osteogenesis may prove to be a treatment alternative for patients requiring condylar reconstruction.

Reconstruction of the mandibular condyle using transport distraction osteogenesis.

Transport distraction osteogenesis was used to reconstruct the articulation of the temporomandibular joint in two patients. Patient 1 underwent a gap arthroplasty for release of a bony ankylosis. Patient 2 had degenerative joint disease after tumor resection. Both patients had painful, limited mouth opening and facial asymmetry as a result of condylar shortening. A reverse-L osteotomy was performed from the sigmoid notch to the posterior border of the mandible. An external transport distraction device was applied, and the segment was advanced superiorly, 1.0 mm per day, until contact was made with the glenoid fossa. After distraction, the bone was found to have remodeled, inducing a new cortical layer on the articular surface. Additionally, a pseudodisk was generated as a result of the transport distraction. The two patients tolerated the procedure well, returning to pain-free normal mouth opening and being able to masticate regular diets.

Intralesional vinblastine injections for the treatment of oral Kaposi's sarcoma: report of 10 patients with 2-year follow-up.

PURPOSE: This study evaluated the use of intralesional vinblastine injections for the treatment of the intraoral lesions of Kaposi's sarcoma. PATIENTS AND METHODS: Eighteen patients were treated with up to three intralesional injections of 0.1 mg/cc vinblastine. RESULTS: All lesions responded to the local injections; 40% required one injection; 31%, two injections; and 29%, three injections. Large, exophytic lesions usually required the multiple injections. No complications were encountered, and the patients tolerated the protocol well. Ten patients were followed for 24 months. Eight died of their general disease during this period. Four patients developed new intraoral lesions, which were treated with, and responded favorably to, the three-injection protocol. CONCLUSION: Intralesional vinblastine injections are an effective and useful treatment alternative for human immunodeficiency virus (HIV)-associated intraoral Kaposi's sarcoma.

Facial asymmetry. The diagnostic challenge.

Evaluation of facial asymmetries requires a complete and systematic approach. This clinical examination is supplemented with radiographic studies including panoramic and cephalometric views. For complex cases CT scans are useful. Evaluation of the shape of the cervical vertebrae seen on lateral cephalometric radiographs can be used to predict potential growth in children.

Using counselors in a multideath disaster.

In the worst possible situation, a disaster results in multiple deaths, requiring the involvement of coroner's and medical examiner's offices. Guidelines offered by the National Association of Medical Examiners and by a national funeral directors' association suggest the use of ministers and chaplains to offer "pastoral" care to family members who have lost a loved one in a disaster. This article offers an example of a disaster protocol based upon national guidelines, but using certified and licensed professional counselors to provide preventive outreach counseling to those family members. Furthermore, this protocol uses a counselor in a key position to provide psychological care to investigative and medical personnel involved in the recovery and identification portions of a disaster.

Effect of mandibular distraction on the temporomandibular joint: Part 1, Canine study.

The effect of osteodistraction on the temporomandibular joint was evaluated in a canine model. Eleven mongrel dogs were used in the study. An intraoral expansion device was placed after an osteotomy was made at the angle of the mandible via an intraoral approach. The mandibles were expanded either fully to 20 mm or partially to 10 mm. After expansion, nine animals were immediately killed; the remaining two were maintained in fixation for an additional 10 weeks. Cephalometric radiographs and computed tomographic scans obtained preoperatively and before killing were evaluated. No gross temporomandibular joint deformation or bodily movement was noted in the expanded or contralateral, unexpanded side. The temporomandibular joints were harvested en bloc for gross and microscopic evaluation. Flattening of the posterior aspect of the expanded condylar head was noted, with thinning of the condylar cartilage. New bone deposition was noted, which was evident as anterior lipping. Condyles maintained in 10 weeks fixation showed reparative changes. No evidence of avascular necrosis, microfracture, or cystic degeneration was noted. This study indicates that the force of distraction can induce bony changes in the temporomandibular joint and that these effects are minimal and reversible.

Effect of mandibular distraction on the temporomandibular joint: Part 2, Clinical study.

Mandibular lengthening by gradual distraction has been gaining popularity. However, the effect of osteodistraction on the temporomandibular joint has been evaluated in patients with craniofacial anomalies who underwent mandibular distraction. Five patients had unilateral expansion and five had bilateral expansion. The mandibles were expanded 1 mm per day until the pogonion was in the midline. Preoperative, immediate, 6-month, and 12-month panoramic and cephalometric radiographs were evaluated. In unilaterally expanded mandibles, the ipsilateral condyle increased in size and volume, became more upright, and was oriented in a more normal vertical axis. The contralateral unexpanded condyle did not show deformational changes. In those mandibles that were bilaterally expanded, both condyles increased in size and volume and became more symmetrical and upright. Osteodistraction appears to affect bone in both local and distant sites. The expanded condyles were stimulated to ensure a more nearly normal shape, size, and configuration.

Microanatomic analysis of the medial antebrachial nerve as a potential donor nerve in maxillofacial grafting.

PURPOSE: To histologically compare the anterior branch of the medial antebrachial cutaneous nerve (MACN) with the sural nerve using biometric techniques. PATIENTS AND METHODS: Twenty-centimeter segments of the right and left (MACN) and sural nerves from three cadavers were analyzed. The number of fascicles within the nerves were counted and the neural to connective tissue ratio was estimated. RESULTS: Sural nerves consistently showed greater amounts of connective tissue between the fascicles than the MACN. Fascicle diameter varied less throughout the length of the MACN. Fascicle diameter varied less throughout the length of the MACN and it showed fewer and larger fascicles, more closely approximating the anatomy of the inferior alveolar nerve. CONCLUSION: These preliminary data suggest that the MACN, on anatomic grounds, is theoretically more suited for grafting to the alveolar and lingual nerves than the sural nerve.

Bilateral bifid mandibular condyles. Report of three cases.

Bilateral bifid mandibular condyles are a rare anomaly that had previously been described only by Hrdlicka in material from skull collections. We present here three cases of bilateral bifid mandibular condyles in patients who sought treatment for other reasons. The radiographic appearance of this anomaly and its embryology are discussed.