Co-exposure to nanoplastics and acetaminophen causes skeletal dysplasia and behavioral abnormalities in zebrafish.

Nanoplastics (NPs) and acetaminophen (APAP) are thought to be common contaminants and are invariably detected in the environment. Despite the increasing awareness of their toxicity to humans and animals, the embryonic toxicity, skeletal development toxicity, and mechanism of action of their combined exposure have not been clarified. This study was performed to investigate whether combined exposure to NPs and APAP induces abnormal embryonic and skeletal development in zebrafish and to explore the potential toxicological mechanisms. All zebrafish juveniles in the high-concentration compound exposure group showed some abnormal phenomena such as pericardial edema, spinal curvature, cartilage developmental abnormality and melanin inhibition together with a significant downward trend in body length. Behavioral data also implicated that the exposure of APAP alone, as well as the co-exposure of NPs and APAP, caused a depression in the total distance, swimming speed and the maximum acceleration. Furthermore, real-time polymerase chain reaction analysis showed that compared with exposure alone, the expression level of genes related to osteogenesis, runx2a, runx2b, Sp7, bmp2b and shh was significantly reduced with compound exposure. These results suggest that the compound exposure of NPs and APAP has adverse impacts on zebrafish embryonic development and skeletal growth.

The establishment of a novel upper cervical complex fracture classification system.

BACKGROUND CONTEXT: Upper cervical complex fractures are associated with high rates of neurological damage and mortality. The Dickman's classification is widely used in the diagnosis of upper cervical complex fractures. However, it falls short of covering the full spectrum of complex fractures. This limitation hinders effective diagnosis and treatment of these injuries. PURPOSE: To address the diagnostic gap in upper cervical complex fractures, the study introduces a novel classification system for these injuries, assessing its reliability and usability. STUDY DESIGN: Proposal of a new classification system for upper cervical complex fractures. PATIENT SAMPLE: The study comprised the clinical data of 242 patients with upper cervical complex fractures, including 32 patients treated at our hospital, along with an additional 210 cases from the literature. OUTCOME MEASURES: The inter-observer and intra-observer reliability (kappa coefficient, κ) of this classification system were investigated by 3 spine surgeons. The 3 researchers independently re-evaluated the upper cervical complex fracture classification system 3 months later. METHODS: The proposed classification categorizes upper cervical complex fractures into 3 main types: Type I combines odontoid and Hangman's fractures into 2 subtypes; Type II merges C1 with odontoid/Hangman's fractures into 3 subtypes; and Type III encompasses a combination of C1, odontoid, and Hangman's fractures, divided into 2 subtypes. Meanwhile, a questionnaire was administered in 15 assessors to evaluate the system's ease of use and clinical applicability. RESULTS: A total of 45 cases (18.6%) unclassifiable by Dickman's classification were successfully categorized using our system. The mean κ value of inter-observer reliability was 0.783, indicating substantial reliability. The mean κ value of intra-observer reliability was 0.862, indicating almost perfect reliability. Meanwhile, thirteen assessors (87.7%) stated that the classification system is easy to remember, easy to apply, and they expressed intentions to apply it in clinical practice in the future. CONCLUSIONS: This system not only offers high confidence and reproducibility but also serves as a precise guide for clinicians in formulating treatment plans. Future prospective applications are warranted to further evaluate this classification system.

The Comparison between Spinal Facet Joint Toothed Plate and Traditional Pedicle Screw-rod on Reduction of Thoracolumbar Fracture.

OBJECTIVE: Thoracolumbar fractures are one of the most common fractures in clinical practice. Surgical intervention is recommended to restore spinal alignment or decompress the nerves when there are unstable fractures or neurological injuries. However, after excessive forward thrust force restoration, facet joint dislocation often occurs between the upper vertebra and the fractured vertebra, which usually leads to unsatisfactory reduction outcomes. Herein, we propose a novel spinal facet joint toothed plate to assist in fracture reduction. The purpose of this study is to evaluate the effectiveness of the new spinal facet joint toothed plate in preventing facet joint dislocation, and its advantages compared to traditional pedicle screw-rod decompression. METHODS: A total of 26 patients in the toothed plate group and 93 patients in the traditional group who experienced thoracolumbar fracture with reduction were retrospectively included. Relevant patients' information and clinical parameters were collected. Furthermore, visual analogue scores (VAS) scores and Oswestry disability index (ODI) scores were also collected. Moreover, imaging parameters were calculated based on radiographs. Correlated data were analyzed by χ2 test and t test. RESULTS: All patients in this study had no postoperative complications. Postoperative VAS scores and ODI scores (p < 0.001) were statistically significant (p < 0.001) in both groups compared with preoperative scores and further decreased (p < 0.001) at final follow-up. In addition, the postoperative vertebral margin ratio (VMR) (p < 0.001) and vertebral angle of the injured vertebrae (p < 0.001) were significantly improved compared with the preoperative period. There were no significant differences in postoperative VAS scores and ODI scores between the two groups. However, toothed plate reduction significantly improved the VMR (p < 0.05) and vertebral angle (p < 0.05) compared with conventional reduction. Ultimately, the total screw accuracy was 98.72% (sum of levels 0 and I), with 100% screw accuracy in the segment related to the tooth plate in the tooth plate group. The dislocation rate was higher in the conventional group (6.45%) than in the new serrated plate repositioning group (0.00%). CONCLUSION: The facet toothed plate assisted reduction method prevents facet joint dislocation and improves fracture reduction compared to traditional reduction technique, hence it could be considered as a novel surgical strategy for thoracolumbar fracture reduction.

The comparison of clinical outcome of fresh type II odontoid fracture treatment between anterior cannulated screws fixation and posterior instrumentation of C1-2 without fusion: a retrospective cohort study.

BACKGROUND: Recently, the excellent outcomes of temporary fixation of C1-2 without fusion in the treatment of odontoid fracture had been reported. It is still unclear if this technique could achieve the equivalent outcomes as the golden standard technique of anterior screw fixation. The objective of this study is to compare the clinical outcome of two treatments of fresh type II odontoid fracture: anterior cannulated screws fixation (ACSF) versus posterior instrumentation of C1-2 without fusion (PIWF). METHODS: This is a retrospective study. This series included 28 males and 8 females, and the mean age was 41.5 years (range, 22 to 70 years). Eleven patients were treated with ACSF, and 25 patients with PIWF. For PIWF, the implants were removed after fracture union was confirmed at 0.75~1.5 years later. All patients underwent preoperative and serial postoperative clinical examinations at approximately 3 months, 6 months, and annually thereafter. The neck disability index (NDI) was used to assess the neck discomfort caused by the operation. The range of rotary motion was evaluated at each visit. All fractures were reassessed postoperatively with serial X-films and CT scans of the cervical spine at each follow-up visit, to evaluate screw position, fracture alignment, and fusion status. RESULTS: All patients achieved immediate spinal stabilization after surgery, and none experienced neurologic deterioration. The follow-up periods ranged from 24 to 60 months. The average range of neck rotation was dramatically lost in PIWF after fixation (46° and 89° respectively in ACSF and PIWF), and recovered to 83° after the implant was removed. The NDI in PIWF was statistically higher than that in ACSF (5 and 13% respectively in ACSF and PIWF) after the first operation and decreased to 8% 1 year after the secondary operation. The fusion rates were 90.9 and 96% respectively in ACSF and PIWF. Both groups had a case of fracture non-union. CONCLUSIONS: For fresh type II odontoid fractures, high rate of fracture union can be achieved by both ACSF and PIWF. For most fresh type II odontoid fractures, anterior screw fixation was the best option for its simplicity and preservation of normal atlanto-axial rotary function. Posterior instrumentation without fusion could preserve most of the atlanto-axial rotary function and lead to moderate neck discomfort and is also a good alternative if anterior screw fixation is contraindicated.

Posterior temporary C1-2 fixation for 3-part fractures of the axis (odontoid dens and Hangman fractures).

Case series study.To report the clinical outcomes of posterior temporary C1-2 fixation for 3-part fracture of the axis (Type II odontoid fracture according to Grauer classification combined with Hangman fracture).The 3-part fracture of the axis is rare and the treatment is controversy.A total of 8 patients with 3-part fracture of the axis were included in this study. X-rays, CT, and MRI prior to surgery were used to evaluate the cervical spine injury. Grauer classification, fracture angulation, and fracture translation were used to evaluate the fracture of dens. The neck disability index (NDI) and range of neck rotary motion were used to assess the neck function.The preoperative fracture angulation and fracture translation were 4.6 ±â€Š1.3° and 2.4 ±â€Š0.6 mm, respectively. The average operation time and blood loss were 109 ±â€Š27 minutes and 49 ±â€Š15 mL. No infection, vascular injuries or neural structure injuries was observed. All patients acquired bone healing at 5.9 ±â€Š2.0 months. The temporary instrumentation was removed at 10.8 ±â€Š1.3 months. The average NDI before and 2 days after removal of instrumentation were 10.1 ±â€Š4.0 and 7.1 ±â€Š3.0, respectively. At 1-year follow-up after instrumentation removal, the NDI was 1.8 ±â€Š0.7, which was much better than immediate NDI after instrumentation removal. The neck rotary motion (left rotation + right rotation) before and 2-day after instrumentation removal were 70.4 ±â€Š6.3° and 119.6 ±â€Š13.1°, respectively. At 1-year follow-up, the average neck rotary motion was 153.1 ±â€Š9.1°, which had significant different with rotary motion 2-day after the removal of temporary instrumentation.With regard to the high fracture fusion rates, low complications, and excellent predictable outcomes in patients treated with posterior temporary C1-2 pedicle screw fixation, the technique may be a suitable choice for 3-part fracture of the axis.