Korean J Urol.  2008 Apr;49(4):320-324.

The Factor Affecting Radical Retropubic Prostatectomy: The Bony Pelvic Shape Imaged by Magnetic Resonance Imaging

• Kim JS
• Im CM
• Kwon DD
• Park K
• Ryu SB

Abstract

PURPOSE: We investigated how the bony pelvic shape, as imaged by preoperative magnetic resonance imaging(MRI), affects radical retropubic prostatectomy(RRP).
MATERIALS AND METHODS
We investigated 27 patients who underwent radical prostatectomy between January 2004 and December 2006 in our hospital. We obtained images of their pelvic bone size on the sagittal plane by performing pelvic MRI. We measured the true conjugate diameter, the obstetric conjugate diameter and the difference between the former and the latter. In addition, we examined the age, body mass index(BMI), prostate-specific antigen(PSA), prostate volume, Gleason's score, pathologic stage, operative time, the estimated blood loss and the surgical margin involvement. We analyzed the factors that affected the estimated blood loss, operative time and surgical margin involvement by multiple linear regression analysis and multiple logistic regression analysis.
RESULTS
The mean age of the patients was 66.7+/-5.3 years, the true conjugate diameter and obsteric conjugate diameter were 105+/-8.9mm and 94.5+/-9.2 mm respectively, the difference of the diameters was 10.7+/-4.3mm, the BMI was 24.1+/-2.6kg/m(2), the PSA was 22.9+/-34.2ng/ml and the prostate volume was 33.7+/-14g. The estimated blood loss was 1,152.2+/-356.4cc, the operation time was 144.4+/-28.6 minutes and 8 patients had positive surgical margins. On the multiple linear regression analysis, the estimated blood loss increased 66cc in proportion to a 1mm difference between the true conjugate diameter and the obstetric conjugate diameter(p<0.001). The BMI was associated with the operative time on the multiple linear regression analysis(p=0.048).
CONCLUSIONS
For patients with RRP, the BMI was associated with the operative time. The estimated blood loss increased in proportion to the difference between the true conjugate diameter and the obstetric conjugate diameter, as measured by pelvic MRI before operation. We suggest that the symphyseal surface variability can be the one of the factors that affects the degree of operative difficulty.

Keyword

Radical retropubic prostatectomy; Magnetic resonance imaging; Pelvic bones

MeSH Terms

Humans
Linear Models
Logistic Models
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Magnetics
Magnets
Operative Time
Pelvic Bones
Prostate
Prostatectomy

Figure

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  Fig. 1 Reconstructed sagittal image by Workstation®, from the prostate magnetic resonance imaging (MRI) and schematic image. *A: true conjugate, †B: obstetric conjugate, ‡C: the closest distance between true conjugate and prostate apex.

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  Fig. 2 Regression plot between the estimated blood loss and the difference of the true conjugate and obstetric conjugate diameters. A: true conjugate, B: obstetric conjugate.

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