Unilateral Condylar Hyperactivity: A Histopathologic Analysis of 47 Patients

Accuracy of skeletal scintigraphy for the evaluation of mandibular growth disorders: a systematic review

Bone scans, reflecting blood flow and metabolic activity in a region of interest, are frequently used to evaluate mandibular growth disorders. Increased uptake is a non-specific finding and can occur as a result of multiple causes. The correlation between radioactive tracer uptake and growth activity has not been consistently demonstrated. The aim of this study was to assess the accuracy of planar skeletal scintigraphy (SS), single-photon emission computed tomography (SPECT), and SPECT with computed tomography (CT) images (SPECT/CT) in detecting abnormal mandibular growth activity compared to clinical and radiographic/tomographic methods (reference standard) and histologic findings. A systematic review was conducted following the PRISMA guidelines. Sensitivity, specificity, and accuracy were calculated for planar SS, SPECT, and SPECT/CT. Compared to the reference standard, SPECT/CT had the best diagnostic accuracy (76.5% sensitivity, 90.4% specificity, 83.2% accuracy), followed by planar SS (81.8% sensitivity, 84.5% specificity, 83.0% accuracy) and SPECT (77.7% sensitivity, 72.4% specificity, 74.5% accuracy). The results of this study indicate that SPECT/CT has the best clinical correlation, but the certainty of the evidence is low. The differences in sensitivity and specificity between the three index tests were not clinically significant. The three tests can be useful, with only a small difference in their diagnostic value. Histopathology was found not to be satisfactory as a reference standard.

Diagnostic accuracy of bone SPECT and SPECT/CT imaging in the diagnosis of unilateral condylar hyperplasia: A systematic review and meta-analysis

Imaging with bone scans plays an important role in the diagnostic path of patients with unilateral condylar hyperactivity or unilateral condylar hyperplasia (UCH). The aim of this study is to perform a systematic review of the diagnostic performance of the bone SPECT and SPECT/CT scan for the diagnosis of UCH. PubMed, SCOPUS and EMBASE were searched electronically to identify diagnostic accuracy studies that assessed the diagnostic value of bone SPECT and SPECT/CT for the diagnosis of UCH, Meta-analyses were performed with Metadisc 1.4 and 2.0. A total of 14 studies, with a total number of 887 patients, were included in the qualitative analysis and 11 studies qualified for meta-analyses. The pooled sensitivity and specificity for the SPECT scan were 0.814 (95 % CI: 0.639-0.915) and 0.774 (95 % CI: 0.655-0.861), for the SPECT/CT scan these were 0.818 (95 % CI: 0.749-0.874) and 0.901 (95 % CI: 0.840-0.945). The summary receiver operating characteristics of the SPECT scan showed an area under the curve of 0.847 (95 % CI: 0.722-0.972) and that of the SPECT/CT scan was 0.928 (95 % CI: 0.876-0.980). CONCLUSION: Both bone SPECT scan and SPECT/CT scan provide a high diagnostic accuracy for UCH. The added value of the SPECT/CT scan is questionable and given the potential disadvantages of the SPECT/CT scan, including the increased radiation dose and costs, the diagnostic modality of first choice in patients with UCH should be a SPECT scan.

Assessment of unilateral condylar hyperplasia with quantitative SPECT/CT

Purpose

The current study aimedto assess condylar activityin patients with unilateral condylar hyperplasia (UCH) with quantitative SPECT/CT.

Patients and methods

This retrospective study included patients with UCH who underwent quantitative SPECT/CT. SPECT analysis and quantification of SPECT/CT were performed, and the maximum count per pixel and SUVmax of either side of the condyles were calculated.

Results

39 patients were included in the analysisand classified into three subgroups according to the percentile differential right-left ratio: inactive group, left active (LA) group, and right active (RA) group. Totally, the SUVmax of the affected side is significantly higher than the unaffected side (active:5.93 ± 2.43 vs inactive:3.62 ± 1.76, P < 0.001), SUVmax-based ratios correlated well with the ratios based on maximum count (R = 0.944, P < 0.001). ROC analysis showed poorSUVmaxperformance in differentiation between theactive condyles and the inactive condyles due to the lower area under the curve (AUC) (0.588). In subgroup analysis, the affected side is significantly higher than the unaffected side in active groups with SUVmax, no significant difference was found between the active sides or the inactive sides of active groups. Interestingly, the SUVmax of the left side was statistically higher than that of the right sidein the inactive group (P = 0.01),while the left side of the right active group has significantlylower activitythan that in the inactive group, meanwhile,the right side showed no significant difference. Furthermore, each side showed no significant difference between the left active group and the inactive group.

Conclusions

SUVmax is not an optimal measurement effectively used to evaluate active condyles. However, SUV ratios correlated well with the count ratios, and the left side of condyles showed a peculiar feature in condyle growth status reflected in radioactivity quantified with SPECT/CT, which needs further study to determine the role in the development of the UCH.

The learning curve of transoral condylectomy; a retrospective analysis of 100 consecutive cases of unilateral condylar hyperplasia

In this study, 100 consecutive scheduled transoral condylectomies for unilateral condylar hyperplasia were included. The safety and surgical performances were assessed, using the operating time, conversion rate and complication rate. The conversion rate learning curve was evaluated with a learning curve cumulative summation (LC-CUSUM). The total conversion rate was 8.0%. The LC-CUSUM for conversion signaled at the 53th procedure, indicating sufficient evidence had accumulated that the surgeon had achieved competence. For procedures 54-100, the conversion rate was 4.0%. The operating time for the transoral condylectomy was 41.5 ± 15.3 min; when a conversion was necessary, the operating time was 101.4 ± 28.3 min (p < 0.05). The estimated operating time in the post-learning phase was 37 min, this was reached after approximately 47 procedures. There was 1 major complication of a permanent inferior alveolar nerve hypoesthesia. The complication rate was not significantly decreased after the learning curve. Within the limitations of the study, it seems that transoral condylectomy for UCH is a safe procedure with several advantages over the traditional preauricular approach. Surgeons starting this procedure should be aware of the potential complications and of the learning curve of approximately 53 procedures.

Diagnostic performance of SPECT-CT imaging in unilateral condylar hyperplasia

Nuclear imaging plays an important role in the diagnostic path of patients with unilateral condylar hyperplasia (UCH). The purpose of this study was to determine the performance of single-photon emission computed tomography-computed tomography (SPECT-CT) in a large group of patients with suspected UCH. This study prospectively included 156 patients with a clinical presentation of progressive mandibular asymmetry. All patients underwent ^99 mTc-HDP SPECT-CT and extensive baseline and follow-up documentation. The relative activity of the ipsilateral condyle in relation to the contralateral condyle was calculated for both the mean and maximum count, and the diagnostic accuracy of different cut-off values was determined. The area under the receiver operating characteristic curve of the SPECT-CT scan was 0.892 for the mean count and 0.873 for the maximum count. The optimal cut-off of> 8% (SPECT-CT mean count) resulted in a sensitivity of 87.0% and a specificity of 88.6%. SPECT-CT showed good diagnostic performance in UCH; however the benefit of the CT scan is questionable and the potential disadvantages have to be weighed against the benefits when compared to standard SPECT scanning. When using SPECT-CT in the diagnostic path in UCH, a mean value cut-off of>8% for the relative activity between the condyles is most accurate.

Diagnosis and Treatment in Unilateral Condylar Hyperplasia

Unilateral condylar hyperplasia (UCH) is an uncommon disease involving progressive facial asymmetry. The aim of this research was to perform an analysis of the diagnosis and treatment of patients with UCH in a clinical series. An observational retrospective study was performed on subjects with progressive facial asymmetry in the lower third of the face; all the subjects were under treatment with condylectomy and orthodontics to improve occlusion and face balance. Variables such as age, sex, clinical type, SPECT (single photon emission computed tomography) intensity and a requirement for secondary surgery were included; the Shapiro Wilk test was performed to analyze the normality of the data and nonparametric analysis and the Kruskal-Wallis or Mann-Whitney tests were used to assess the association between the SPECT difference and the variables, where 2-tailed p values < 0.05 were considered to be statistically significant. Forty-nine patients between 10 and 45 y.o. (average age: 19.1 ± 7.4 y.o.) were included in the study. There were 41 female (83.6%) and 8 male (16.4%) subjects. The SPECT analysis comparing the right and left condyles with more than 10% in caption of the isotope was present in 46 subjects; the results obtained using SPECT were not statistically related to the age or sex of the sample (p = 0.277). The patients were classified into clinical types I, II and III, and no correlations could be confirmed between the clinical type and other variables. High condylectomy was conducted on all patients, among which 14 patients underwent a secondary surgery for orthognathic or cosmetic treatment, and was not related to the initial variables used in diagnosis (p = 0.98); interestingly, the second surgical treatment was more present in the clinical type I and in subjects under 16 years old with no statistical differences. Clinical analysis, medical records, 3D imaging and SPECT should be used as a complementary analysis in assessing the diagnosis of UCH and progressive facial asymmetry.

Micro-computed tomography evaluation of bone architecture in various forms of unilateral condylar hyperplasia

Condylar hyperplasia is one of the causes of facial asymmetry and malocclusion, characterized by enlargement of the lower jaw due to excessive condyle growth activity. The aim of this study was to use micro-computed tomography (micro-CT) to evaluate the bone architecture of the condylar head and determine whether there are differences between patients with various forms of unilateral condylar hyperplasia (UCH): hemimandibular hyperplasia, elongation, and mixed form. The cohort consisted of 28 patients with a mean age of 21.9 years. All patients underwent surgical treatment (condylar shaving) for active pathological growth activity. The portion of the condylar head removed was imaged by micro-CT and subsequently evaluated. Micro-CT imaging and semiquantitative and quantitative evaluation of the bone structure (percentage bone volume, surface density, trabecular thickness, trabecular separation, degree of anisotropy, and porosity of the subchondral bone) did not reveal significant differences between the individual types of condylar hyperplasia (P > 0.05). There were no significant differences in bone structure between the anterior and posterior portions of the condylar head. No statistically significant differences between individual groups of UCH were found in the micro-CT evaluation of the condylar head bone architecture.

Histologic findings and related diagnostic methods in condylar hyperactivity

Condylar hyperactivity (CH) is a rare condition that entails a progressive deviation and deformation of the mandible. There is no consensus regarding characteristic histopathological features or a standardized diagnostic process; thus, histopathological analysis of the condyle cannot confirm or exclude an active CH after condylectomy is performed. An electronic search was performed in Medline, Embase, Web of Science, LILACS and grey literature up to December 2019. Additionally, a manual search was performed. Risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale and the Institute of Health Economics Quality Appraisal. All analyses were performed independently and in duplicate. Seventeen articles from 660 were included. Six articles were cross-sectional studies and 11 were case series. Almost all the articles (14) described an augmented thickness of the cartilage layer associated with cartilage islands within the subchondral bone in patients affected by CH. Histological findings seem to be mostly related to the age of the sample rather than a characteristic description of CH. No clear association was found between SPECT/scintigram uptake and a specific histological finding. Hence, there is a necessity for the development of specific tools for evaluating and reporting studies where histology is needed for diagnosis confirmation.

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

Hemifacial hyperplasia (HFH) is characterized by an increase in volume of all affected tissues of half of the face. It is present at birth, subsequently grows proportionally, and stops growing before adulthood. Unilateral condylar hyperplasia (UCH) consists of progressive asymmetric growth of the mandible and develops typically in early adulthood. Both disorders have an unknown aetiology. The overgrowth limited to one body part suggests somatic mosaicism, as this has been found in other similar localized overgrowth disorders. Often this includes a variant in a gene in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway. Here we report the case of an HFH patient with asymmetry present at birth, in whom a progressive growth pattern similar to UCH subsequently occurred, causing marked mandibular asymmetry. A condylectomy was successfully performed to stop the progressive growth. Somatic mosaicism for a mutation in PIK3CA was detected in the condylar tissue. This finding might indicate that both HFH and UCH can be caused by variants in genes in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway, similar to other disorders that result in asymmetrical bodily overgrowth.

Histopathological features of condylar hyperplasia and condylar Osteochondroma: a comparison study

Background

Both mandibular condylar hyperplasia and condylar osteochondroma can lead to maxillofacial skeletal asymmetry and malocclusion, although they exhibit different biological behavior. This study attempted to compare the histological features of mandibular condylar hyperplasia and condylar osteochondroma using hematoxylin-and-eosin (H&E) staining, and immunohistochemistry staining of PCNA and EXT1 with quantitative analysis method.

Results

The H&E staining showed that condylar hyperplasia and condylar osteochondroma could be divided into four histological types and exhibited features of different endochondral ossification stages. There was evidence of a thicker cartilage cap in condylar osteochondroma as compared condylar hyperplasia (P = 0.018). The percentage of bone formation in condylar osteochondroma was larger than was found in condylar hyperplasia (P = 0.04). Immunohistochemical staining showed that PCNA was mainly located in the undifferentiated mesenchymal layer and the hypertrophic cartilage layer, and there were more PCNA positive cells in the condylar osteochondroma (P = 0.007). EXT1 was mainly expressed in the cartilage layer, and there was also a higher positive rate of EXT1 in condylar osteochondroma (P = 0.0366). The thicker cartilage cap, higher bone formation rate and higher PCNA positive rate indicated a higher rate of proliferative activity in condylar osteochondroma. The more significant positive rate of EXT1 in condylar osteochondroma implied differential biological characteristic as compared to condylar hyperplasia.

Conclusions

These features might be useful in histopathologically distinguishing condylar hyperplasia and osteochondroma.

Anatomical and Clinical Implications in Neocondyle Stability After a Condylectomy

: A condylectomy of the mandibular condyle is considered to be the treatment of choice in most cases of condylar head hyperactivity. The aim of the procedure is to remove the growth center of the mandible which is responsible for the mandibular enlargement and asymmetry. This surgical procedure has an impact on the condyle shape and position, but the restoration of mandibular movement and a stable joint position (namely, the proper alignment of the newly shaped condylar head within the condyle fossa) should also be considered important surgical outcomes. In this article, the authors present their own experience in performing condylectomies with an arthroplasty procedure and a special forced suturing technique (FST) in terms of achieving early, accurate mandibular movement and maintaining a stable condyle position in early and late outcomes.

MATERIALS AND METHODS

A modified high condylectomy with arthroplasty and FST results had been studied in anatomical, radiological, and clinical model.

RESULTS

Early findings after FST are promising. A slight improvement in lateral jaw movement was noted after condylectomy with arthroplasty (P < 0.05) both in early and late follow-up. Incisal opening, mandibular protrusion, and lateral movement were sustained. A stable condyle position within the fossa was achieved in each case of condylectomy with arthroplasty (P < 0.05).

CONCLUSIONS

The FST condylectomy and reattachment of the lateral pterygoid muscle in a new, wider position provided an improvement in lateral jaw movement as well as in incisal opening and mandibular protrusion in early follow-up examination compared to the presurgical values. It seems that the FST enabled a better new condylar head position in the glenoid fossa and improved early functional mandibular movement.

The Biomechanical Effect of the Sagittal Split Ramus Osteotomy on the Temporomandibular Joint: Current Perspectives on the Remodeling Spectrum

The sagittal split ramus osteotomy is a key approach for treating dentofacial deformities. Although it delivers excellent results, the sagittal split ramus osteotomy is believed to induce stress to the temporomandibular joint. Potential stress inducers could be classified as intra- and postoperative factors resulting in an inflammatory response and molecular cascades, which initiate physiological remodeling. Occasionally, this process exceeds its capacity and causes pathological remodeling, through either degenerative joint disease or condylar resorption. Hard evidence on how orthognathic surgery causes inflammation and how this inflammation is linked to the spectrum of remodeling remains scarce. Current concepts on this matter are mainly based on clinical observations and molecular mechanisms are extrapolated from fundamental research in other body parts or joints. This perspective study provides an overview of current knowledge on molecular pathways and biomechanical effects in temporomandibular joint remodeling. It provides research directions that could lead to acquiring fundamental evidence of the relation of orthognathic surgery and inflammation and its role in remodeling. Performing osteotomies in animal models and identifying inflammatory mediators as well as their effect on the joint seem promising. Patients affected by pathological remodeling can also provide samples for histological as well as molecular analysis. Individual susceptibility analysis by linking certain suspect phenotypes to genetic variation could identify the cause and molecular pathway responsible for degenerative joint disease and condylar resorption, ultimately leading to clinically applicable treatment and prevention strategies.

Condylectomy and "surgery first" approach: An expedited treatment for condylar hyperplasia in a patient with facial asymmetry

Condylar Hyperplasia (CH) is a self-limiting pathology condition that produces severe facial deformity at the expense of mandibular asymmetry. In this case report a 15-year-old female patient was diagnosed with Unilateral Condylar Hiperplasia (UCH) by mean of single-photon emission computed tomography (SPECT) and histological study. A high condylectomy in the right condyle was performed to stop the active status of the hyperplasia. A month after condylectomy, orthognathic jaw impaction and asymmetric mandibular setback surgery was performed with the Surgery First Approach (SFA). After 10 days, orthodontic appointments were made every two weeks during 4 months. The active phase of treatment lasted 14 months. Excellent facial and occlusal outcomes were obtained and after 24 months in retention the results remained stable.

A correlational study of serum alkaline phosphatase level and developmental mandibular laterognathism

The abnormal cartilage/bone metabolism in unilateral condyle may be a direct factor that contributes to developmental mandibular laterognathism. However, although many molecules have been demonstrated to play crucial roles in the development of temporomandibular joints, the exact molecular mechanisms that lead to the disrupted condylar cartilage/bone development were greatly unknown. In this retrospective study, our findings revealed that serum alkaline phosphatase (ALP) level in adult patients with developmental mandibular laterognathism was lower than that in control subjects, and the serum ALP levels continue to reduce in adult patients (>20 years old). Although the exact relationship between the lower serum ALP level and developmental mandibular laterognathism is unclear, the findings further support the opinion that the condylar growth may sustain for a long time in the affected condyle in patients with developmental mandibular laterognathism and offer an alternative choice to use total serum ALP activity as a possible biomarker to assess condylar growth activity in patients with developmental mandibular laterognathism.

Clinical value of 99Tcm-MDP SPECT bone scintigraphy in the diagnosis of unilateral condylar hyperplasia

Purpose. To investigate the clinical value of ⁹⁹Tc^m-MDP SPECT for the diagnosis of unilateral condylar hyperplasia (UCH). Methods. One hundred forty-nine patients who underwent mandibular ⁹⁹Tc^m-MDP SPECT between January 2009 and December 2012 were studied, including 105 cases that were clinically suspected of UCH and 44 comparable cases without UCH as a control group. Results. Increased bone activity was observed in the affected condyles for all UCH patients. In the UCH group, the relative percentage uptake on the affected side was 59% (SD ± 4.3%), significantly higher than the 41% (SD ± 4.1%) uptake on the contralateral side (P<0.001). Similarly, the condyle/skull ratio was significantly higher for the affected side (1.66 ± 0.63) than for the contralateral side (1.34 ± 0.34, P < 0.01. No significant difference was found in the control group between the left and right condyles. Values for the sensitivity (95%), specificity (61%), positive (84.4%) and negative (84.6%) predictive values, and accuracy (84.5%) for ⁹⁹Tc^m-MDP SPECT in the diagnosis of UCH were calculated. However, for the hyperplastic condyle, no correlation was observed between the thickness of each cartilage layer and the relative uptake in the SPECT image. Conclusion. ⁹⁹Tc^m-MDP SPECT is accurate for diagnosing UCH and can provide a reference for treatment options.

Condylar process contributes to mandibular asymmetry: In vivo 3D MRI study

The purpose of this study was to investigate the differences in mandibular morphology between the deviated and nondeviated sides in patients with noncongenital skeletal mandibular asymmetry. Divergences from control values were assessed to determine which region of the mandible contributes most to mandibular asymmetry. We measured various dimensions of the mandible in 20 young patients and 20 controls using noninvasive high-quality three-dimensional (3D) volumetric magnetic resonance imaging. Mandibular dimensions including the length of the condylar process were significantly greater on the nondeviated side of patients than the deviated side. Measurements of the deviated side were similar to control values, but measurements of the nondeviated side including condylar process length differed significantly from control values. These findings strongly suggest that overgrowth of the condylar process on the nondeviated side in these patients results in mandibular asymmetry, and therefore needs attention in orthodontic treatment, orthognathic surgery, and follow-up.