Objectives A radiographic study was designed to measure the relationship of the exiting nerve root and its surroundings to the corresponding intervertebral disc for percutaneous transforaminal endoscopic lumbar interbody fusion to better understand the regional anatomy and to improve clinical applications. Methods A retrospective study from January 2017 to October 2017 was conducted at Tianjin Hospital. CT images were obtained from patients presenting low back pain (110 patients), and analysis was performed bilaterally from L2‐3 to L5S1. In the rotating coronal plane we analyzed: the nerve root–dural sac distance at the superior and inferior margins of the disc (Js, Ji); the nerve root–pedicle distance at the medial, middle, and lateral borders of the pedicle (Pa, Pb, Pc); the pedicle width (W); and the safe working zone, defined as a trapezoid bounded by the inferior pedicle and the exiting nerve root (S). In the transverse plane, the nerve root‐articular process and the shortest distance for the nerve root‐articular process joint surface were analyzed at the superior and inferior margins of the disc (Gs, Gi), respectively. The groups were analyzed using ANOVA, and paired t‐tests were used to compare the left and right sides. Results From L2‐3 to L5S1, the distance of the nerve root to the dural sac was larger at the inferior margin of the disc. From L2‐3 to L5S1, each segment of the vertebral nerve root‐pedicle distance gradually decreased from medial to lateral. From L2‐3 to L5S1, the distance from the exiting nerve root to the middle and lateral margins of the pedicle gradually decreased, with L5S1 being the minimum. Some significant differences were observed between the left and right sides for L4‐5 and L5S1. The pedicle width of the vertebral body and the mean area for the safe working zone gradually increased from L2‐3 to L5S1. In the axial plane, the shortest distance between the nerve root and articular process joint surface at the inferior margin of the disc was greater than the distance for the nerve root to the articular process at the superior margin of the disc from L2‐3 to L5S1. There were no significant differences between the two sides. Conclusions It is more difficult to implant a cage with a width of 10 mm above the L3‐4 level. By removing part of the superior articular process, the safe working area can be expanded, and damage to the nerve or other structures can be avoided when implanting a cage.

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Objective Instability of the dorsal radioulnar ligament (DRUL) is caused by multiple factors from bony and soft tissue structures. Studies of DRUJ instability based on MRI have rarely been reported. This study aims to investigate related instability factors in the distal radioulnar joint (DRUJ) after trauma based on MRI imaging. Methods The MRI imaging was performed on 121 post‐traumatic patients with or without DRUJ instability from April 2021 to April 2022. All patients demonstrated pain or attenuated wrist ligamentous tissue quality with physical examination. The interesting variables, including age, sex, the distal radioulnar transverse shape, the triangular fibrocartilage complex (TFCC), DRUL, the volar radioulnar ligament (VRUL), distal interosseus membrane (DIOM), the extensor carpi ulnaris (ECU), and pronator quadratus (PQ), were analyzed using univariable and multivariable logistic regression model. The different variables were compared in radar plots and bar chart. Results An average age of 121 patients was 42.16 ± 16.07 years. The 50.4% DRUJ instability existed in all patients and the distal oblique bundle (DOB) presented in 20.7% of patients. The TFCC ( p = 0.03), present DIOM ( p = 0.001), and PQ ( p = 0.006) were identified to be significant in final multivariable logistic model. The percentage of patients with ligament injuries were general higher in DRUJ instability group. The patients with absent DIOM had a higher rate in DRUJ instability, TFCC, and ECU injury. There was higher stability in shape of C‐type, intact TFCC, and present DIOM. Conclusion DRUJ instability is closely associated with TFCC, DIOM, and PQ. It could provide a potential for early detection of potential instability risk and taking necessary preventive measures.

BACKGROUND: The treatment of sacral fractures accompanied by nerve injury is complex and often leads to an unsatisfactory prognosis and poor quality of life in patients. OBJECTIVE: The present study aimed to investigate the clinical value of using 3.0T magnetic resonance contrast-enhanced three-dimensional (MR CE-3D) nerve view magnetic resonance neurography (MRN) in the diagnosis and management of a sacral fracture accompanied by a sacral plexus injury. METHODS: Thirty-two patients with a sacral fracture accompanied by a sacral plexus injury, including 24 cases of Denis spinal trauma type II and 8 cases of type III, were enrolled in the study. All patients had symptoms or signs of lumbosacral nerve injury, and an MRN examination was performed to clarify the location and severity of the sacral nerve injury. Segmental localization of the sacral plexus was done to indicate the site of the injury as being intra-spinal (IS), intra-foraminal (IF), or extra-foraminal (EF), and the severity of the nerve injury was determined as being mild, moderate, or severe. Surgical nerve exploration was then conducted in six patients with severe nerve injury. The location and severity of the nerve injury were recorded using intra-operative direct vision, and the results were statistically compared with the MRN examination results. RESULTS: MRN showed that 81 segments had mild sacral plexus injuries (8 segments of IS, 20 segments of IF, 53 segments of EF), 78 segments had moderate sacral plexus injuries (8 segments of IS, 37 segments of IF, and 33 segments of EF), and 19 segments had severe sacral plexus injuries (7 segments of IS, 9 segments of IF, and 3 segments of EF). The six patients who underwent surgery had the following intra-operative direct vision results: 3 segments of moderate injury (IF) and 20 segments of severe injury (7 segments of IS, 10 segments of IF, 3 segments of EF). There was no statistically significant difference in the results between the intra-operative direct vision and those of the MRN examination (p> 0.05). CONCLUSION: MR CE-3D nerve view can clearly and accurately demonstrate the location and severity of sacral nerve injury accompanied by a sacral fracture, and has the potential for being the first choice of examination method for this kind of injury, which would be of important clinical value.