A radiographic simulation study of fixed superior pubic ramus fractures with retrograde screw insertion

Determinants for successful medullary fixation of the superior ramus

OBJECTIVES

The purpose of this study is to determine what demographic and anatomical variables affect successful placement of a superior medullary ramus screw, and how they affect the maximal diameter of that screw.

METHODS

Design: Prognostic Level IV SETTING: Level I Trauma Center Patients/Participants: Two hundred consecutive patients underwent computed tomography (CT) of the pelvis. We included those patients aged 18 and older without osseous injury or abnormalities precluding measurement.

INTERVENTION

3D reconstructions of the pelvis were created, and a virtual 3.5 mm cylindrical implant was placed from the pubic tubercle to the lateral cortex of the ilium. Success was defined as a bicortical virtual screw path from the ramus to the lateral ilium without cortical perforation. The cylinder was then expanded to model varying screw diameters. We then repeated this same process for unicortical retrograde screw insertion ending medial to the acetabular joint.

MAIN OUTCOME MEASURES

Successful screw placement and maximum screw diameter.

RESULTS

A 3.5 mm screw was successfully placed in 187 patients (93.5 %). One male (1/107, 0.9 %) and 12 females (12/93, 12.9 %) could not accommodate a 3.5 mm screw. All cases of perforation occurred lateral to the obturator foramen. Increasing height was associated with success, and male gender was associated with the ability to accommodate screws with a diameter 6.5 mm and larger.

CONCLUSIONS

Most patients can accommodate a 3.5 mm screw from the pubic tubercle to the ilium. Height and gender should be noted when planning medullary ramus fixation.

Dependable Automated Approach for Measuring the Retrograde Superior Ramus Screw Corridor in Pelvic Fracture Fixation

BACKGROUND

Precise measurement of the intraosseous corridor within the superior pubic ramus is essential for the accurate percutaneous placement of a retrograde superior ramus screw (SRS). However, conventional manual measurement methods are often subjective, leading to variations in results among observers. Our goal was to develop an automated and dependable method for determining the retrograde SRS corridor.

METHODS

We developed an automated technique that utilized a computed tomography (CT) image-based search algorithm to identify the retrograde SRS corridor with the maximum diameter. We evaluated the reliability of this automated approach in comparison to a manual method using 17 pelves. Subsequently, we used both methods to measure the diameter, length, and orientation of the retrograde SRS corridor in 204 pelves in a Chinese population and assessed the intra- and interobserver agreement of each method by calculating the root-mean-square error (RMSE) and constructing Bland-Altman plots. We determined the screw applicability (percentages of hemipelves that could be treated with specific sizes of screws) for each method. Additionally, we investigated potential factors influencing the corridor, such as sex, age, height, and weight, through regression analysis.

RESULTS

The intra- and interobserver intraclass correlation coefficients (ICCs) for the automated method (0.998 and 0.995) were higher than those for the manual approach (0.925 and 0.918) in the assessment of the corridor diameter. Furthermore, the diameter identified by the automated method was notably larger than the diameter measured with the manual method, with a mean difference and RMSE of 0.9 mm and 1.1 mm, respectively. The automated method revealed a significantly smaller corridor diameter in females than in males (an average of 7.5 and 10.4 mm, respectively). Moreover, use of the automated method allowed 80.6% of the females to be managed with a 4.5-mm screw while a 6.5-mm screw could be utilized in 19.4%, surpassing the capabilities of the manual method. Female sex had the most substantial impact on corridor diameter (β = -0.583).

CONCLUSIONS

The automated method exhibited better reliability than the manual method in measuring the retrograde SRS corridor, and showed a larger corridor diameter for screw placement. Females had a significantly smaller corridor diameter than males. Given the intricate nature of the automated approach, which entails utilizing different software and interactive procedures, our current method is not readily applicable for traumatologists. We are working on developing integrated software with the goal of providing a more user-friendly solution for traumatologists in the near future.

LEVEL OF EVIDENCE

Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Evaluation of the effect of pelvis type in percutaneous acetabular column fixation: a computed tomography study

This study aimed to evaluate the effect of pelvis type in percutaneous acetabular column fixation. What is the effect of pelvis type in percutaneous acetabular colon fixation? The available pelvic computed tomography (CT) scans which were obtained in the diagnostic imaging center with a 1 mm slice width were evaluated. The pelvic type was classified with the help of MPR (Multiplanar Reformat) and 3D (Three Dimensional) imaging modes. All evaluated bony pelvic structures were anatomically intact. 40 types of android, gynecoid, anthropoid, and platypelloid pelvis were determined. CT sections were created in MPR imaging mode. Anterior obturator oblique (AOO) and inlet images were created for anterior column evaluation, while iliac oblique (IO) and outlet images were created for posterior column evaluation. The possibility of obtaining a linear corridor for acetabular columns was investigated by measuring corridor width and lengthon images of pelvic CTs. A linear corridor could not be obtained between the pubic tubercle and the supraacetabular region of 12 (30%) CTs in the anterior column of gynecoid pelvis group. The diameter of the anterior column corridor was below 5.5 mm in 10 (25%) of Gynecoid pelvis group, 5 (12.5%) of Anthropoid pelvis group, and 10 of Platypelloid pelvis group, , and all those scans belonged to the female gender. There was a statistically significant difference between pelvis types in terms of anterior and posterior column diameters (p <0.001). While the android pelvis type had the highest diameter and corridor length in both anterior column and posterior column measurements, the gynecoid pelvic type had the lowest diameter and corridor length. In the evaluations made according to gender, both anterior and posterior column diameters were larger and longer in males than in females (p <0.001). Pelvis type is an important factor which can affect anterior and posterior column diameter and length of acetabulum. Pelvic typing before acetabular surgery can help the surgeon determining the most appropriate patient position, surgical approach, and implant selection. Level of Evidence: Level 2.

Is percutaneous fixation of the superior pubic ramus possible in all types of pelvis?

BACKGROUND

The impact of pelvis type on percutaneous fixation of the superior pubic ramus was investigated in this study.

METHODS

One hundred fifty pelvic CTs (female/male: 75/75) without anatomical changes in the pelvis were studied. Pelvis CT examinations with 1mm section width, pelvis typing, anterior obturator oblique, and inlet section images were created using the MPR and 3D imaging mode of the imaging system. In these images, whether a linear corridor could be obtained for the superior pubic ramus, corridor width, length, and angle values in the transverse and sagittal planes were measured in pelvic CT where linear corridor could be obtained.

RESULTS

In 11 samples (7.3 %) (group 1), no linear corridor for the superior pubic ramus could be obtained in any way. All pelvis types in this group were gynecoid, and all belonged to female patients. A linear corridor in the superior pubic ramus could be easily obtained in all pelvic CTs with Android pelvic type. The superior pubic ramus was 8.2±1.8 mm in width and 116.7±12.8 mm in length. The corridor width was measured below 5 mm in 20 (13.3%) pelvic CT images (group 2). Corridor width showed a statistically signif-icant difference depending on the pelvic type and gender.

CONCLUSION

The pelvic type is a determinat factor for the fixation of the percutaneous superior pubic ramus. For this reason, pelvic typing using MPR and 3D imaging mode in preoperative CT examination; is effective in surgical planning, implant, and surgical position selection.

[Research progress on minimally invasive treatment of anterior pelvic ring fracture]

OBJECTIVE

To summarize the related research results of minimally invasive treatment of anterior pelvic ring fracture, and to improve the understanding of minimally invasive treatment of anterior pelvic ring fracture.

METHODS

The literature of minimally invasive treatment of anterior pelvic ring fracture at domestic and overseas in recent years was reviewed, and the reduction and fixation methods of minimally invasive treatment were summarized and analyzed.

RESULTS

The pelvic reduction frame may be an effective auxiliary method for minimally invasive reduction of pelvis. The fixation methods of anterior pelvic ring include percutaneous screw fixation, stent fixation, and percutaneous plate fixation.

CONCLUSION

One kind of fixation is not applicable to all types of anterior pelvic ring fracture, and the fixation method should be selected according to the type of fracture and the patient's condition to minimize the complications.