The significance of the best puncture side bone cement/vertebral volume ratio to prevent paravertebral vein leakage of bone cement during vertebroplasty: a retrospective study

OBJECTIVES

To verify the clinical significance of the best puncture-side bone cement/vertebral volume ratio (PSBCV/VV%) and bone cement leakage in paravertebral veins during vertebroplasty.

METHODS

This was a retrospective analysis of a total of 210 patients from September 2021 to December 2022, who were divided into an observation group (110 patients) and a control group (100 patients). In the observation group, patients' preoperative computed tomography (CT) data were imported into Mimics software, and the VV was calculated using the three-dimensional (3D) reconstruction function. Then, based on the best PSBCV/VV% of 13.68% determined in a previous study, the optimal PSBCV to be injected during vertebroplasty was calculated. In the control group, vertebroplasty was performed directly using the conventional method. The incidence of cement leakage into paravertebral veins was observed postoperatively in both groups.

RESULTS

There were no statistically significant differences (P > 0.05) in the evaluated indicators between the two groups pre- or postoperatively, including the anterior vertebral margin height, mid-vertebral height, injured vertebral Cobb angle, visual analogue scale (VAS) score, and Oswestry Disability Index (ODI). Intragroup comparisons showed improvements in the anterior vertebral height, mid-vertebral height, injured vertebral Cobb angle, VAS score, and ODI after surgery compared with before surgery (P < 0.05). In the observation group, there were 3 cases of cement leakage into the paravertebral veins, for a leakage rate of 2.7%. In the control group, there were 11 cases of cement leakage into the paravertebral veins, for a leakage rate of 11%. The difference in the leakage rate between the two groups was statistically significant (P = 0.016).

CONCLUSION

In vertebroplasty, preoperative VV calculations using Mimics software, combined with calculation of the PSBCV according to the best PSBCV/VV% (13.68%), can effectively prevent leakage of bone cement into paravertebral veins and further prevent serious life-threatening complications such as pulmonary embolism.

Correlation analysis of the puncture-side bone cement/vertebral body volume ratio and bone cement leakage in the paravertebral vein in vertebroplasty

Objectives

To explore the influencing factors of bone cement leakage in the paravertebral vein after vertebroplasty for the treatment of osteoporotic vertebral compression fractures (OVCFs) and to determine the correlation between the puncture-side bone cement/vertebral body volume ratio and bone cement leakage in the paravertebral vein.

Methods

This was a retrospective analysis of 495 patients (585 vertebral bodies) with OVCFs treated from August 2018 to May 2021 in our hospital. The patients’ postoperative CT data were imported into Mimics software, and the three-dimensional(3D) reconstruction function was used to calculate the bone cement volume (BCV), puncture-side bone cement volume (PSBCV), and vertebral body volume (VBV); the bone cement/vertebral body volume ratio (BCV/VCV%) and puncture-side bone cement/vertebral body volume ratio (PSBCV/VCV%) were additionally calculated. Sex, Age, Body mass index(BMI), Bone density, BCV, PSBCV, VBV, BCV/VCV%, and PSBCV/VCV were compared between the leakage group and the non-leakage group. Logistic regression analysis was used to assess the correlations between the factors that statistically significantly differed between the two groups and the presence of leakage in the paravertebral veins. A receiver operating characteristic (ROC) curve was used to determine the diagnostic value of the PSBCV/VCV% and to obtain the optional cut-off value.

Results

A total of 102 males and 393 females with an average age of 72.89 (52 ~ 93) years were included in our study. There were 57 cases of cement leakage (59 vertebral bodies) in the paravertebral vein. There were 438 patients (526 vertebral bodies) without paravertebral cement leakage. Univariate analysis showed that the differences in sex, bone density, PSBCV, and PSBCV/VCV% between the two groups were statistically significant (P < 0.05). Logistic regression analysis showed that there were correlations between sex, bone density, and PSBCV/VCV% and the presence of paravertebral cement leakage (P < 0.05). The ROC curve showed that the area under the curve of the PSBCV/VCV% for the diagnosis of cement leakage in the paravertebral vein was greater than 0.65, and P < 0.05, indicating a diagnostic value. The best cut-off point for the diagnosis of paravertebral cement leakage with the PSBCV/VCV% was 13.68%, with a sensitivity of 84.7% and specificity of 37.8%.

Conclusion

Sex, bone density, and PSBCV/VCV% are risk factors for cement leakage in the paravertebral veins after vertebroplasty for the treatment of OVCFs; the PSBCV/VCV% is strongly associated with paravertebral venous leakage, and the optimal PSBCV/VCV% is 13.68%. When the PSBCV/VCV% exceeds the optimal value, the risk of cement leakage in the paravertebral vein becomes significantly increased.

3D-Printed Screw-Rod Auxiliary System for Unstable Atlas Fractures: A Retrospective Analysis

Objective

To develop and validate the efficacy of a 3D‐printed screw‐rod auxiliary system for unstable atlas fractures.

Methods

This research is a retrospective analysis, and a total of 14 patients, including 11 males and three females, were enrolled in our hospital from January 2017 to March 2019 who underwent occipitocervical fusion assisted by the 3D‐printed screw‐rod auxiliary system were reviewed, and with an average age of 53.21 ± 14.81 years, an average body mass index (BMI) of 23.61 ± 1.93 kg/m². The operation time, blood loss and radiation times during the operation were recorded. The maximum fracture displacement values of pre‐ and post‐operation were measured based on CT imaging. All screw grades were evaluated after surgery. The occipital‐cervical 2 (O‐C₂) angle and occipitocervical inclination (OCI) angle of pre‐operation, post‐operation and the last following‐up were measured. The dysphagia scale 3 months after surgery and at the last follow‐up, the Neck Disability Index (NDI) 3 months after surgery and at the last follow‐up were assessed.

Results

All patients were completed the surgery successfully. There was no patient with severe dysphagia or aggravation of nerve injury. The follow‐up was from 12 to 14 months, and with an average of 12.5 months. The average surgery time, average blood loss and average radiation times for the 14 patients were 112.14 min, 171.43 mL and 5.07 times, respectively. There was a significant difference in maximum fracture displacement between pre‐ and post‐operation values (P < 0.05). A total of 56 screws were inserted in 14 patients, among them, three screws were classified as grade 1, and the other screws were classified as grade 0. There was a significant difference in the O‐C₂ between pre‐operation and 3 days after operation (P = 0.002); There was a significant difference in OCI angles between pre‐operation and 3 days after operation (P < 0.05); there was no significant difference in the O‐C₂ or OCI angle between 3 days after the operation and the last follow‐up (P = 0.079; P = 0.201). The dysphagia scales of two patients were assessed as mild at 3 months after surgery, and the others were assessed as normal at 3 months after surgery. All patients' dysphagia scores returned to normal at the last follow‐up. The average NDI and average neck Visual Analogue Scale (VAS) scores at the last follow‐up were 2.53 and 8.41, respectively.

Conclusion

It can objectively restore the OCI to normal with few post‐operative complications under the assistance of a screw‐rod auxiliary system to perform occipitocervical fusion for unstable atlas fractures and atlantooccipital joint instability.

[Cone beam CT-derived adaptive radiotherapy for setup error assessment and correction in whole breast intensity modulated radiotherapy]

OBJECTIVE

To quantify the setup error (SE) in breast cancer patients treated with intensity modulated radiotherapy (IMRT) based on cone beam CT (CBCT), and to explore the feasibility of using several CBCT scans to presume and correct SE in the treatment for breast cancer patients.

METHODS

Eighteen breast cancer patients after breast conserving surgery who underwent whole breast IMRT were included in this study. Three dimensional interfraction motion before and after on-line CBCT-based corrections were quantified. The on-line CBCT-based corrections were performed using automated greyscale match. The system SE (Σ) and random error (σ) were calculated for each patient based on the consecutive multiple online scanning based on CBCT (≥5). The trends in magnitudes of Σ and σwere assessed during the treatment.

RESULTS

The magnitude variation of Σ was less than 1 mm before and after on-line CBCT-based corrections. As the CBCT scanning times increase (before 10 times), the Σ in anteroposterior (AP) direction was increased significantly, and σin three dimensional directions was also increased after 7 times of CBCT scanning. After on-line CBCT-based corrections, the Σ showed a steady trend by variation near zero for the first 20 times irradiation; but after 20 times, the Σ in AP and superoinferior (SI) directions was increased slightly (less than 0.5 mm), and σdecreased in three-dimensional directions. There were no significant differences for Σ, σand setup margin (SM) before and after on-line CBCT-based corrections in all three directions (P>0.05).

CONCLUSIONS

For breast cancer patients who underwent IMRT after breast conserving surgery, the setup error is relatively stable during the whole irradiation. The first 5 CBCT scans are suitable to presume and correct SE, and also can be used as the right time for adaptive radiotherapy planning revision.

Pharmacokinetics and tissue distribution of zidovudine in rats following intravenous administration of zidovudine myristate loaded liposomes

Liposomes accumulating in the reticuloendothelial system (RES) appear to be a promising vehicle to improve the therapeutic index of anti-HIV drugs such as zidovudine (AZT). Since the entrapment efficiency of AZT in liposomes was found to be low and AZT leakage from liposomes is fast, zidovudine myristate (AZT-M) was synthesized as a prodrug, and AZT-M incorporated liposomes in a lyophilized form were prepared with an average diameter of 90 nm and an encapsulation efficiency of 98% after reconstitution. The pharmacokinetic profiles and tissue distribution of AZT after i.v. administration of AZT-M liposomes in rats were investigated, and the results were compared with those after i.v. administration of AZT solution. AZT levels in plasma were significantly higher following application of AZT-M liposomes compared with AZT solution, and AUC0_infinity increased from 5.0 +/- 0.7 micromol x min x ml(-1) to 8.2 +/- 1.7 micromol x min x ml(-1) accordingly. Tissue distribution studies also confirmed higher concentrations of AZT in organs of RES and brain, suggesting that AZT-M liposomes might be promising candidates for therapy of HIV infections.

Phylogenetic relationships among two species of golden monkey and three species of leaf monkey inferred from rDNA variation

Restriction maps of rDNA repeats of five species of Colobinae and three outgroup taxa, Hylobates leucogenys, Macaca mulatta, and Macaca irus, were constructed using 15 restriction endonucleases and cloned 18S and 28S rRNA gene probes. The site variation between Rhinopithecus roxellana and Rhinopithecus bieti is comparable to that between Presbytis françoisi and Preshytis phayrei, implying that R. bieti is a valid species rather than a subspecies of R. roxellana. Phylogenetic analysis on the 47 informative sites supports the case for Rhinopithecus being an independent genus and closely related to Presbytis. Furthermore, branch lengths of the tree seem to support the hypothesis that the leaf monkeys share some ancestral traits as well as some automorphic characters.