Gateno Jaime, Coppelson Kevin B, Kuang Tianshu, Poliak Cathy D, Xia James J
Chairman, Oral and Maxillofacial Surgery Department, Houston Methodist Hospital, Houston, TX; Professor of Oral and Maxillofacial Surgery, Houston Methodist Academic Institute, Houston, TX; and Professor of Clinical Surgery (Oral and Maxillofacial), Weill-Cornell Medical College, New York, NY.
Former Advance Oral and Maxillofacial Surgery Fellow, Department of Oral and Maxillofacial Surgery, Houston Methodist Hospital, Houston, TX.
J Oral Maxillofac Surg. 2021 May;79(5):1122-1132. doi: 10.1016/j.joms.2020.12.034. Epub 2020 Dec 29.
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.
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.
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.
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.
我们目前对单侧髁突增生（UCH）的认识是由奥布韦格泽提出的。他假设UCH是两种不同的情况：半侧下颌骨增生和半侧下颌骨延长。这一假设基于以下三个假设：1）在UCH中，过度生长的方向是双峰的——垂直或水平，很少有病例呈斜向生长；2）UCH可以在髁突无明显增大和有明显增大的情况下使半侧下颌骨扩大；3）髁突扩大与过度生长的方向之间存在关联——最小程度的扩大导致水平生长，而明显的增大导致垂直移位。本研究的目的是检验这些假设。
我们分析了40例UCH患者的计算机断层扫描图像。首先，我们使用西尔弗曼聚类分析来确定过度生长的方向在UCH人群中的分布情况。接下来，我们评估半侧下颌骨过度生长与髁突增大之间的关系，以确认过度生长可以独立于髁突扩大而发生。最后，我们评估髁突增大程度与过度生长方向之间的关系，以确定髁突扩大是否决定生长方向。
我们的第一项研究表明，认为UCH是双峰的普遍印象是错误的。UCH中的生长向量呈单峰分布，绝大多数病例呈对角生长。我们的第二项研究证实了UCH可以在髁突无明显增大和有明显增大的情况下使半侧下颌骨扩大这一观察结果。我们的最后一项研究确定，在UCH中，髁突扩大程度与过度生长方向之间没有关联。
本研究结果反驳了UCH是半侧下颌骨增生和半侧下颌骨延长这两种不同情况的观点。它还为UCH的病理生理学提供了新的见解。
