Unilateral condylar hyperplasia in hemifacial hyperplasia, is there genetic proof of overgrowth?

Mineralization and thickness of the condylar cortex in skeletal remains of children's mandibles: A preliminary study

OBJECTIVE

To explore the relationship between the volumetric bone mineral density (vBMD), the thickness of the condylar cortex (Tcortex) and the hemimandibular volumes (Vhemimandible) of symmetrical and asymmetrical mandibles of children.

DESIGN

The data collection consisted of 92 archeological skeletal remains of children's mandibles between 1 and 12 years old. The mandibles were digitalized with a computed tomography (CT) scan, and three dimensional models were obtained. Vhemimandible was calculated using the optimal symmetry plane. The volumes were used to calculate the asymmetry index (AI). Mandibles with an AI of ≥ 3% (N = 9) and a sample of the most symmetrical mandibles (N = 9) were selected for this research. Three groups were created: a symmetrical, an asymmetrical and a pooled group. Micro-CT was used to measure the vBMD and Tcortex in four volumes of interest. The AI was calculated for these parameters as well.

RESULTS

Significant correlations were found between the vBMD and the Tcortex in the pooled group (P < .01) and between the AI of the vBMD and the AI of the Tcortex in the pooled (P < .01) and symmetrical group (P < .05). No significant correlations were found between the vBMD and the Vhemimandible and between the respective AIs. Between the Tcortex and the Vhemimandible a significant correlation was found in the pooled and asymmetrical group.

CONCLUSION

There is a relationship between the vBMD and the Tcortex. The correlations between the Tcortex and the Vhemimandible are insufficient to draw firm conclusions. A relationship between the vBMD and Vhemimandible was not confirmed in this study.

Temporomandibular Joint Prosthesis in a Patient with Congenital Infiltrating Lipomatosis of the Face with Bony Ankylosis of the Temporomandibular Joint: A Case Report

Hemifacial hyperplasia (HFH) is a rare congenital disorder characterized by marked unilateral overgrowth of the facial tissues. A subtype of HFH is congenital infiltrating lipomatosis of the face (CIL-F). This disease is characterized by unilateral diffuse infiltration of mature adipose cells in the facial soft tissue and is associated with skeletal hypertrophy. This work aims to report a case of a CIL-F patient with right facial asymmetry and progressive growth at adolescent age, causing mandibular asymmetry due to signs of concomitant unilateral condylar hyperplasia. At the age of seventeen, a condylectomy was performed to stop the progression of asymmetric mandibular growth. Five years later, the patient developed CIL-F-associated temporomandibular joint ankylosis, manifesting as progressive restricted mouth opening along with temporal facial pain. In this CIL-F patient, a TMJ reconstruction with an alloplastic total joint prosthesis was successfully performed with optimal maximal mouth opening, complete alleviation of temporal facial pain, and stable dental occlusion one year postoperatively. A TMJ reconstruction with a complete alloplastic total joint prosthesis proved to be a predictable, stable, and safe treatment option in a patient with CIL-F-associated TMJ ankylosis who was previously treated with condylectomy due to progressive mandibular asymmetry.

Effect of Swell1 on regulating chondrocyte hypertrophy during the condylar osteochondral development process in mice

Chondrocyte hypertrophy is a significant factor in cartilage development, yet the molecular mechanism for cell volume expand during the process is remains unclear. In the present study, the relationship between Swell1, a cell volume regulated anion channel, and chondrocyte hypertrophy was explored. The results reveal that the spatiotemporal expression of Swell1 was similar with the development process of hypertrophic chondrocytes in condyles. Through Col10a1 mediated knock out of Swell1 in hypertrophy chondrocytes, we found that there are less obvious boundary between different condylar cartilage layers in which increased hypertrophic chondrocytes were scattered in all three cartilage layers. The cortical bone mass and bone mineral density in the subchondral bone significantly increased. Additionally, knock out of Swell1 could increase the expression of OCN in the femur condyle. Based on the aforementioned findings, a conclusion could be drawn that Swell1 is a significant factor in chondrocyte hypertrophy during the condylar osteochondral development process, and there was some difference between the mandibular and femur condyles, which will provide some new clues for understanding the development of cartilage and related diseases.

Slice Functional Condylectomy and Piezosurgery: A Proposal in Unilateral Condylar Hyperplasia Treatment

ABSTRACT

Condylar hyperplasia is a temporomandibular joint progressive disease characterized by an excessive growth of the mandibular condyle. Condylar overgrowth represents one of the most common causes of facial asymmetry in early adulthood. To date, there is not a clearly established origin of the disease: genetic, traumatic, infective, vascular, and functional factors are involved hypotheses. Clinically, condylar hyperplasia presentation is characterized by an asymmetry of the lower third of the face, deviation of the chin, inclination of the labial line and malocclusion. Several treatments have been proposed over the years in the treatment of mandibular condyle hyperplasia, but to date a gold standard has not been defined. Two are the main approaches: condylectomy and orthognathic surgery, isolated or in a combination. Many condylectomy technique differentiations have been developed: high, low, and proportional, are the most performed. In this technical note, the Slice Functional Condylectomy (SFC), a modification of the proportional condylectomy is presented.

A Better Understanding of Unilateral Condylar Hyperplasia of the Mandible

PURPOSE

Our current understanding of unilateral condylar hyperplasia (UCH) was put forth by Obwegeser. He hypothesized that UCH is 2 separate conditions: hemimandibular hyperplasia and hemimandibular elongation. This hypothesis was based on the following 3 assumptions: 1) the direction of overgrowth, in UCH, is bimodal-vertical or horizontal, with rare cases growing obliquely; 2) UCH can expand a hemimandible with and without significant condylar enlargement; and 3) there is an association between the condylar expansion and the direction of overgrowth-minimal expansion resulting in horizontal growth and significant enlargement causing vertical displacement. The purpose of this study was to test these assumptions.

PATIENTS AND METHODS

We analyzed the computed tomography scans of 40 patients with UCH. First, we used a Silverman Cluster analysis to determine how the direction of overgrowth is distributed in the UCH population. Next, we evaluated the relationship between hemimandibular overgrowth and condylar enlargement to confirm that overgrowth can occur independently of condylar expansion. Finally, we assessed the relationship between the degree of condylar enlargement and the direction of overgrowth to ascertain if condylar expansion determines the direction of growth.

RESULTS

Our first investigation demonstrates that the general impression that UCH is bimodal is wrong. The growth vectors in UCH are unimodally distributed, with the vast majority of cases growing diagonally. Our second investigation confirms the observation that UCH can expand a hemimandible with and without significant condylar enlargement. Our last investigation determined that in UCH, there is no association between the degree of condylar expansion and the direction of the overgrowth.

CONCLUSIONS

The results of this study disprove the idea that UCH is 2 different conditions: hemimandibular hyperplasia and hemimandibular elongation. It also provides new insights about the pathophysiology of UCH.