Width of the presacral space in Nigerian adults

Determination of the width of the presacral space on magnetic resonance imaging among adults in south-western Nigeria

BACKGROUND

The presacral space is a clinically relevant potential space and contents may give rise to a variety of benign and malignant conditions, hence the need for detailed knowledge of its dimensions.

PURPOSE

To determine the width of the presacral space and existing variations among adults in south-western Nigeria using a magnetic resonance imaging (MRI) technique.

MATERIAL AND METHODS

A total of 369 consenting adults were included in the study. Measurements of the presacral space were then made electronically by consensus of two radiologists. Values derived were recorded and subjected to analyses of variance.

RESULTS

The mean normal widths of the presacral space in men and women were 11.7 mm and 11.1 mm at the S1 level, 11.7 mm and 10.35 mm at the S2 level, and 12.3 mm and 9.7 mm at the S3 level, respectively. Measurements of the presacral space width were significantly larger in the male population. Variations in the dimensions due to age greater than 40 years, male sex, and increasing body mass index (BMI) were also noted.

CONCLUSION

This study provides baseline dimensions under more physiological conditions and gives more accurate information about the true width of the space in Nigerian adults. Variations due to age, sex, and BMI may also be considered while interpreting abnormal values.

Suspensory Ligaments of the Female Genital Organs: MRI Evaluation with Intraoperative Correlation

The uterus, which plays an important role in the reproductive process, provides a home for the developing fetus and so must be in a stable, though flexible, location. Various structures with suspensory ligaments help provide this berth. MRI with high spatial resolution allows us to detect and evaluate these relatively fine structures. Under physiologic conditions, MRI can be used to depict uterine and ovarian ligaments (ie, the uterosacral, cardinal, and round ligaments, as well as the suspensory ligament of the ovary). In the presence of pathologic conditions (inflammation, endometriosis, tumors), the suspensory ligaments may appear thickened or invaded, which makes their delineation easier. Understanding the normal anatomy of the suspensory ligaments of the female genital organs and using a standardized nomenclature are essential for identifying and reporting related pathologic conditions. The female pelvic anatomy and the suspensory ligaments of the female genital organs are described as depicted with MRI. Also, the compartmental anatomy of the female pelvis is explained, including the extraperitoneal pelvic spaces. Finally, a checklist is provided for structured reporting of the MRI findings in the female pelvis. Online supplemental material is available for this article. ^©RSNA, 2018.

The presacral space and its impact on sacral neuromodulator implantation

PURPOSE

We describe the presacral space and its potential impact on sacral neuromodulator implantation and bowel injury.

MATERIALS AND METHODS

Parasagittal images containing bilateral sacral foramina (S2-S4) were examined on 45 pelvic magnetic resonance images. Images were excluded from analysis if they were poor quality or had any history causing distortion of normal anatomy. We measured the natural angle between the foramina and the dorsal skin to approximate the needle angulation during neuromodulator electrode placement. Using these angles we measured the distance from the skin to any bowel (D1), the skin to the dorsal sacrum (D2) and then calculated the distance from the dorsal sacrum to any bowel (D3).

RESULTS

Mean subject age was 45 years (range 19 to 78) and body mass index was 27.9 kg/m(2) (range 18.6 to 56.2). At S3 the mean foraminal angle and D3 were 46 +/- 8.4 degrees and 27.4 +/- 11.7 mm, respectively. Increasing age was moderately correlated to widening D3 at each foramina (r = 0.3, Pearson's p <0.05). Body mass index did not consistently vary with D3 at any foramina.

CONCLUSIONS

Our measurements suggest that the presacral space can be expected to be approximately 27 mm at the level of S3 where the neuromodulator electrode is implanted. It is possible to encounter bowel while performing this implantation using standard techniques and equipment. We recommend the standard use of fluoroscopy during placement.

Determination of the width of the presacral space on magnetic resonance imaging

Presacral space enlargement may be the first sign of certain diseases. The normal width of the presacral space has not been widely investigated and in all previous studies was calculated from lateral radiographs obtained at barium enema examination. Our study determined the normal width of the presacral space on MRI and investigated a possible difference between men and women. The width of the presacral space was measured retrospectively from sagittal T2-weighted MR images of 193 patients (87 males; 106 females, aged 18-83 years). Presacral space width was measured separately for S1, S2, and S3 vertebral levels from the anterior surface of the vertebral bodies to the closest part of the posterior wall of the rectum. Differences between male and female subjects were analyzed by t-tests. Normal mean widths of the presacral space in men and women were 16.2 mm and 11.9 mm for S1, 14.9 mm and 11.2 mm for S2, and 13.0 mm and 10.6 mm for S3, respectively. Measurements of the presacral space width in men were significantly larger than in women at all three levels (P < 0.001 for S1, P < 0.001 for S2, P = 0.006 for S3). In summary, the presacral space width measured on MRI was found to be significantly larger in the male than in the female population.