In our clinic, the current preferred primary treatment regime for unilateral condylar hyperactivity is a proportional condylectomy in order to prevent secondary orthognathic surgery. Until recently, to determine the indicated size of reduction during surgery, we used a ‘panorex-free-hand’ method to measure the difference between left and right ramus heights. The problem encountered with this method was that our TMJ surgeons measured differences in the amount to resect during surgery. Other 2D and 3D method comparisons were unavailable. The aim of this study was to determine the most reproducible ramus height measuring method. Differences in left/right ramus height were measured in 32 patients using three methods: one 3D and two 2D. The inter- and intra-observer reliabilities were determined for each method. All methods showed excellent intra-observer reliability (ICC > 0.9). Excellent inter-observer reliability was also attained with the panorex-bisection method (ICC > 0.9), while the CBCT and panorex-free-hand gave good results (0.75 < ICC < 0.9). However, the lower boundary of the 95% CI (0.06−0.97) of the inter-observer reliability regarding the panorex-free-hand was poor. Therefore, we discourage the use of the panorex-free-hand method to measure ramus height differences in clinical practice. The panorex-bisection method was the most reproducible method. When planning a proportional condylectomy, we advise applying the panorex-bisection method or using an optimized 3D-measuring method.

Unilateral condylar hyperplasia is a rare growth disorder originating in the growth centre of the mandibular condyles and resulting in facial asymmetry. Primary treatment consists of condylectomy. In this cross-sectional research, limitations in mandibular function and oral health related quality of life were measured with the Mandibular Function Impairment Questionnaire and the Oral Health Impact Profile (NL49). The study included 17 patients who underwent treatment for unilateral condylar hyperplasia with a condylectomy in the University Medical Center Groningen between 1997 and 2012. The median (IQR) scores of the Mandibular Function Impairment Questionnaire (8,0 [1,0; 15,0]) and the Oral Health Impact Profile (25,0 [3,0; 53,0] were low compared to other conditions involving the mandible. A higher age was associated with increased limitations in mandibular function (rs = 0,588 (p = 0,013)). After a condylectomy for unilateral condylar hyperplasia the functional impairment of the mandible and the decrease in oral health related quality of life are low. Unilaterale condylaire hyperplasie is een zeldzame groeistoornis die uitgaat van het groeicentrum van de processus condylaris met asymmetrie van het aangezicht tot gevolg. De primaire behandeling bestaat uit een condylectomie. In dit cross-sectionele onderzoek werden beperkingen in mandibulaire functie en de mondgezondheidgerelateerde levenskwaliteit gemeten met de Mandibulair Function Impairment Questionnaire en de Oral Health Impact Profile (NL49). Er werden 17 patiënten geïncludeerd die tussen 1997 en 2012 in het Universitair Medisch Centrum Groningen werden behandeld met een condylectomie vanwege een unilaterale condylaire hyperplasie. De mediane (IQR) score op de Mandibulair Function Impairment Questionnaire (8,0 [1,0; 15,0]) en de Oral Health Impact Profile (25,0 [3,0; 53,0]) waren laag in vergelijking met scores bij andere aandoeningen. Een hogere leeftijd werd geassocieerd met meer beperkingen in mandibulaire functie (rs = 0,588 (p = 0,013)). Na een condylectomie bij unilaterale condylaire hyperplasie blijken de functiebeperkingen en de afname van de mondgezondheidgerelateerde levenskwaliteit gering.

Condylar hyperplasia of the mandible is an uncommon idiopathic disorder of the jaw characterised by increased volume of the condyle, unilaterally or bilaterally, leading to facial asymmetry, mandibular deviation, malocclusion and articular dysfunction. The authors present one case of unilateral condylar hyperplasia of a 16-year-old patient affected by severe facial asymmetry. Conventional X-rays examinations, multislice spiral CT and bone SPECT were used for the final diagnosis of primary condyle hyperplasia. The patient was treated with a combined orthodontic and surgical approach. Treatment of condylar hyperplasia with a combined orthodontic and surgical approach including condylectomy yield good aesthetic and functional outcomes.