Target Registration Errors in Navigation-assisted Mandibular Surgery According to the Tracking Methods and the Type of Markers

Background: This study was conducted to evaluate the accuracy of navigation process according to the type of tracking methods and registration markers. The target registration errors (TREs) were measured at seven anatomical landmarks of the mandible for evaluation. Methods: Four different experiments were performed to obtain the TREs using two different tracking methods, the optical tracker (Polaris) and the electromagnetic (EM) tracker (Aurora), and two different types of registration markers, invasive and noninvasive markers. All comparisons of TREs were statistically analyzed using SPSS and Python-based statistical package (Pingouin). Results: The average TRE values obtained from the four different experiments were as follows: 1) 0.85 mm using invasive marker and Aurora, 2) 1.06 mm using invasive marker and Polaris, 3) 1.43 mm using noninvasive marker and Aurora, and 4) 1.57 mm using noninvasive marker and Polaris. All comparisons among the type of markers and the seven anatomical landmarks revealed statistically significant differences, except for the type of tracking system. Although the comparison between the modality of the tracking system showed no significant differences, the EM-based approach consistently demonstrated better performances than the optical type in all comparisons. Conclusions: This study demonstrates that, irrespective of the tracking modality, the invasive marker is a better choice in terms of accuracy. When using the noninvasive marker, it is important to consider the increased TREs. In the present study, the noninvasive marker caused a maximum increment of TREs of approximately 0.81 mm compared with the invasive marker. Furthermore, EM-based tracking using an invasive marker may result in the best accuracy for the mandible.

Correlation Between Salivary, Platelet and Central Serotonin Levels in Children

ABSTRACT:Background:Serotonin (5-HT) is a neurotransmitter synthesized in both the central nervous system (CNS) and in enterochromaffin cells of the gut. 5-HT biosynthesis is separate between the periphery and the CNS. Any observed correlations between centrally and peripherally measured 5-HT remain to be elucidated. Previous efforts have looked for a noninvasive marker of central serotonin, including serotonin in whole blood, plasma, platelets, saliva, and urine; however, results are conflicting.Aim:Finding a noninvasive marker for central serotonin turnover that can be used for diagnosis and therapeutic monitoring in patients with primary neurotransmitter deficiencies.Methods:Inclusion criterion was all children presenting with neurological symptoms whose clinical investigations included lumbar puncture (LP) for cerebrospinal fluid (CSF) collection and neurotransmitter metabolite analysis, were recruited. For central serotonin turnover, the serotonin metabolite 5-hydroxyindoleacetic acid (5HIAA) was used. Bivariate correlation between the serotonin levels in CSF (5HIAA), platelets, and saliva was calculated.Results:Twenty-six patients (aged 6 months to 15 years) with various neurologic presentations had LP for CSF collection and neurotransmitter metabolite analysis as part of their clinical care. An additional salivary and blood sample was obtained at the same time. Eighteen patients had suitable samples for quantitative measure of serotonin. There was no correlation between platelet serotonin and CSF 5HIAA levels (Pearson’s coefficient of correlation – PCC: 0.010) or between salivary serotonin and CSF 5HIAA (PCC: 0.258). There was a strong negative correlation between salivary and platelet serotonin (PCC: −0.679).Conclusion:Our findings suggest that salivary serotonin measurement is not a suitable noninvasive marker for measuring central serotonin turnover.

Detection of Pepsin in Oral Secretions of Infants with and without Laryngomalacia

Objectives: Laryngomalacia is a common cause of stridor in infants and is associated with laryngopharyngeal reflux (LPR). Although pepsin in operative supraglottic lavage specimens is associated with severe laryngomalacia, detection of pepsin in oral secretions has not been demonstrated in an outpatient setting. Methods: Children <2 years old with laryngomalacia diagnosed by flexible laryngoscopy and children without stridor were selected. Oral secretion samples were obtained in clinic from all subjects. Pepsin, IL-1β, and IL-8 enzyme-linked immunosorbent assays were performed to determine presence of LPR. Results: Sixteen laryngomalacia and sixteen controls were enrolled. Pepsin was detected more frequently in oral secretions of patients with laryngomalacia (13/16) than in controls (2/16; P < .001). Four patients with laryngomalacia developed symptoms requiring supraglottoplasty. Presence and level of salivary pepsin was not significantly associated with need for surgical management, nor were the levels or presence of IL-1β or IL-8 significantly associated with presence or level of pepsin, diagnosis of laryngomalacia, or need for operative management. Conclusion: Pepsin in saliva appears to be associated with laryngomalacia, suggesting a role for salivary pepsin as a noninvasive marker of LPR in patients with laryngomalacia. Future studies will determine the utility of this test in laryngomalacia.