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Objective: To investigate the size and morphology of the temporomandibular joint (TMJ) articular disc and condyle in young asymptomatic adults by using magnetic resonance imaging (MRI) and to provide a reference for clinical diagnosis and scientific study of temporomandibular disorders (TMD). Methods: Overall, 93 undergraduate volunteers without TMD were enrolled from the freshmen pool at the Qingdao University. All participants underwent MRI of the oblique sagittal and oblique coronal TMJ planes. The articular disc and condyle were subsequently measured, and their morphology was evaluated. The obtained data were then grouped and analyzed statistically. Finally, intragroup correlation coefficient (ICC) was used to evaluate the interobserver measurement reliability. Results: We totally received 186 TMJ imaging samples. Based on our analysis, disc’s anterior band in young asymptomatic adult females were thicker than males of the same age (p = 0.024). Moreover, the media-lateral dimensions of the condylar head of adult females were shorter than males of equal age (P＜0.001). The bilateral articular disc morphology was the same in 72.4% of subjects while the condylar morphology was the same in 63.4% of participants. Finally, using measurement reliability assessment, we demonstrated that our conclusions are reliable (ICC ≥0.7). Conclusion: The thickness of the anterior band of the disc and the media-lateral dimensions of the condylar head were gender-related. Additionally, the morphology of the bilateral articular disc and condyle was different among the subset of young asymptomatic adults.

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Objective Although Caspar cervical retractor system (CCRS) is commonly utilized in anterior cervical decompression and fixation (ACDF), most urban hospitals still use both traditional S retractor and CCRS in conventional anterior cervical surgeries. Related data to evaluate the effect are required to be reported. The aim of this study is to compare the efficacy between using the traditional cervical S retractor and CCRS in anterior cervical decompression and fixation ACDF. Methods The retrospective study that total 360 patients received ACDF using different retractors (traditional S retractor or CCRS) were enrolled in this study from January 2010 to January 2020. Width change rate of cervical prevertebral soft tissue, throat symptoms, and subjective experiences of the operating surgeons were evaluated by t‐test or analysis of variance (ANOVA) respectively. Results The width change rate of prevertebral soft tissue was significantly higher in the S retractor group than that of the CCRS group both in single segment group (40.9% vs 20.8%, P < 0.05) and double segments group (45.8% vs 25.2%; p < 0.05). In the three segments group, the width change rate of prevertebral soft tissue was higher in the S retractor group than that of the CCRS group, but with no statistical significance (27.3% vs 23.6%; P > 0.05). The incidence rates of dysphagia, dyspnea, and throat discomfort in the traditional S retractor group were significantly higher compared to the CCRS group (P < 0.05), while satisfactory rate of surgeon was higher in the CCRS group (P < 0.05). However, there was no correlation between anterior soft tissue rate and operative time (P > 0.05), as well as the width change rate of anterior soft tissue and the DNRS score (P > 0.05). Conclusion CCRS was superior compared to the traditional S retractor in reducing the postoperative complications and the postoperative fatigue of surgeon. Meanwhile, the width change rate of prevertebral soft tissue was not related to operative time and DNRS score.

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Objective. A magnetic resonance neurography (MRN) study was conducted to assess the neurological safety of endoscopic transforaminal lumbar intervertebral fusion (endo-TLIF). Materials and Methods. A total of 56 healthy volunteers (29 men, 27 women; average age, 44 yr; age range, 21-60 yr) were included in the study. Coronal MRN images were collected from L2/L3 to L5/S1. The working triangle, modified working zone, and safest working zone areas, as well as the vertical and horizontal safe operation diameters, were measured. Linear regression analyses were conducted to explore the correlations between general characteristics (sex, age, height, body mass index) and the measured radiographic indicators. Results. MRN can effectively evaluate the operation zone of endo-TLIF. The safest working zone, modified working zone, and working triangle areas were largest at L4/L5 (92.4 ± 23.4, 136 ± 35.6, and 197 ± 41.7 mm 2 , respectively) and smallest at L2/L3 (45.5 ± 12.9, 68.1 ± 19.5, and 92.6 ± 24.4 mm 2 , respectively). The vertical safe operation diameter was large at L4/L5 and L2/L3 (5.34 ± 0.8 and 5.42 ± 0.9 mm, respectively) and smallest at L5/S1 (2.94 ± 0.9 mm). The horizontal safe operation diameter was large at L4/L5 (7.28 ± 1.2 mm) and smaller at L5/S1 and L2/L3 (4.28 ± 1.0 and 4.77 ± 0.8 mm, respectively). Conclusions. L4/L5 has the lowest risk of nerve injury, and may be the safest level for beginners initiating endo-TLIF in their practice. We recommend that coronal MRN is routinely performed before endo-TLIF to minimize the risk of neurological injury.

Objectives The aim of this study was to investigate the etiology of temporomandibular disorder (TMD) in young patients using clinical and magnetic resonance imaging (MRI) features of the lateral pterygoid muscle (LPM). Materials and methods The patients were divided into four groups: healthy control, disc without displacement (DWoD), disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR) groups. Demographic information and clinical symptoms of patients in each group were recorded. LPM textures on magnetic resonance imaging (MRI) were compared among all groups. LPM fasciculation was examined. Results Patient sex or age did not differ significantly among groups, while several clinical symptoms and signs and some LPM texture parameters did. The proportion of type B LPM fascicles was significantly higher in DDWR and DDWoR groups than in healthy control and DWoD groups. Conclusion In this study, patients in DDWR and DDWoR groups showed unclear texture, no obvious regularity, and relatively uniform gray distribution on MRI of LPM. Clinical relevance This study found that the texture of the LPM in young TMD patients was different from that in normal people, especially in TMD patients with anterior disc displacement. Changes of the LPM may affect the position of the articular disc, thus provides a direction for scholars to study the etiology of TMD.

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