The repeatability of measurements of male pelvic floor anatomy and function made from transperineal ultrasound images of healthy men and those before and after prostatectomy

Transperineal pelvic floor ultrasound in male

INTRODUCTION

The pelvic floor (PF) is a highly complex structure which may be affected by various stimulating factors like decreased PF support. As ultrasound can dynamically observe the position and mobility of anatomical structures, However, there are very few studies on PF ultrasound in males.

MATERIALS AND METHODS

Twenty-one male patients with normal conditions underwent transperineal pelvic floor ultrasound (TPFU) examination. Ultrasound was performed in a supine lithotomy position. The probe was pressed on the sagittal plane of the perineum and adjusted till the anorectal angle, as well as bladder, were located and the median prostate and pubic symphysis were visible on the sagittal plane. TPFU was carried out to observe the patterns of pelvic floor movement during different phases, measure ultrasound parameters of the PF in men, and assess the potential applications and prospects of the male PF.

RESULTS

Two-dimensional male PF ultrasound can detect the bladder, prostate, male urethra, anus, rectum. Resting, Valsalva, and contraction phases of the PF are clearly shown, the pelvic organs in the Valsalva phase shift to the dorsal foot side, and shift to the cephalic ventral side when the levator ani muscle (LAM) contracts. Three-dimensional male PF ultrasound can visually show the shape and structure of the levator ani muscle hiatus.

CONCLUSION

It is a feasible examination tool for detecting PF disorders. However, there are still many fields to explore in the future.

Pelvic floor muscle length changes with breathing in males: A preliminary report

The study aimed to identify whether pelvic floor muscles modulate length with breathing, and if any length changes induced by breathing relate to abdominal cavity displacement and intra-abdominal pressure. To investigate these relationships, displacement of pelvic landmarks that related to pelvic floor muscle length using transperineal ultrasound imaging, breath volume, intra-abdominal pressure, abdominal and ribcage displacement, and abdominal and anal sphincter muscle electromyography were measured during quiet breathing and breathing with increased dead-space in ten healthy men. Pelvic floor muscle landmark displacement modulated with ribcage motion during breathing. This relationship was stronger for: i) motion of the urethrovesical junction (puborectalis muscle length change) than the mid-urethra landmark (striated urethral sphincter muscle length change), and ii) dead-space breathing in standing than dead-space breathing in supine or quiet breathing in standing. In most (but not all) participants, the urethrovesical junction descended during inspiration and elevated during expiration. Striated urethral sphincter length changes during the respiratory cycle was independent of intra-abdominal pressure. In summary, breathing involves pelvic floor muscle length changes and is consistent with the role of these muscles during respiration to aid maintenance of continence, lung ventilation and/or provision of support to the abdominal cavity. Clinicians who train pelvic floor muscles need to be aware that length change of pelvic floor muscles is expected with breathing.

The relationship between pre- and postprostatectomy measures of pelvic floor muscle function and development of early incontinence after surgery

AIMS

The aim of this study is to investigate (i) whether pelvic floor muscle (PFM) shortening can be enhanced by provision of training focused on striated urethral sphincter (SUS) with feedback before prostatectomy, (ii) whether PFM shortening during voluntary efforts and coughing before and after prostatectomy differs between men who do and do not report symptoms of urinary incontinence 1 month after prostatectomy, and (iii) the relationship between severity of incontinence after prostatectomy and features of pelvic floor function (muscle shortening) and urethral length before and after prostatectomy.

METHODS

Sixty men referred for preoperative PFM training before radical prostatectomy participated. The International Continence Society Male Short Form questionnaire was used to quantify continence status. Transperineal ultrasound (US) imaging was used to record pelvic displacements related to activation of striated urethral sphincter, bulbocavernosus (BC) and puborectalis muscles during cough, "natural" voluntary contraction following pamphlet instruction, and trained voluntary contraction after formal physiotherapist instruction including US feedback.

RESULTS

Pelvic floor displacements following training differed between continent and incontinent men; continent participants demonstrated increased SUS shortening after training (compared with "natural"), but no difference was observed between trained and "natural" contractions for incontinent participants. Motion at ano-rectal junction during cough was reduced following surgery, but voluntary and involuntary activation of SUS or BC was not consistently affected by surgery.

CONCLUSIONS

Participants' capacity to improve function of the SUS with training appears related to postprostatectomy continence outcome.

Evaluation of inter- and intra-observer variations in prostate gland delineation using CT-alone versus CT/TPUS

Background

This study aims to explore the role of four-dimensional (4D) transperineal ultrasound (TPUS) in the contouring of prostate gland with planning computed tomography (CT) images, in the absence of magnetic resonance imaging (MRI).

Materials and methods

Five radiation oncologists (ROs) performed two rounds of prostate gland contouring (single-blinded) on CT-alone and CT/TPUS datasets obtained from 10 patients who underwent TPUS-guided external beam radiotherapy. Parameters include prostate volume, DICE similarity coefficient (DSC) and centroid position. Wilcoxon signed-rank test assessed the significance of inter-modality differences, and the intraclass correlation coefficient (ICC ) reflected inter- and intra-observer reliability of parameters.

Results

Inter-modality analysis revealed high agreement (based on DSC and centroid position) of prostate gland contours between CT-alone and CT/TPUS. Statistical significant difference was observed in the superior-inferior direction of the prostate centroid position (p = 0.011). All modalities yielded excellent inter-observer reliability of delineated prostate volume with ICC > 0.9, mean DSC > 0.8 and centroid position: CT-alone (ICC = 1.000) and CT/TPUS (ICC = 0.999) left-right (L/R); CT-alone (ICC = 0.999) and CT/TPUS (ICC = 0.998) anterior-posterior (A/P); CT-alone (ICC = 0.999) and CT/TPUS (ICC = 1.000) superior-inferior (S/I). Similarly, all modalities yielded excellent intra-observer reliability of delineated prostate volume, ICC > 0.9 and mean DSC > 0.8. Lastly, intra-observer reliability was excellent on both imaging modalities for the prostate centroid position, ICC > 0.9.

Conclusion

TPUS does not add significantly to the amount of anatomical information provided by CT images. However, TPUS can supplement planning CT to achieve a higher positional accuracy in the S/I direction if access to CT/MRI fusion is limited.

The influence of prostatectomy and body position on location and displacement of pelvic landmarks with pelvic floor muscle contraction

AIMS

To compare pelvic floor muscle (PFM) anatomy and function (i) between pre- and post-prostatectomy in standing, and (ii) between sitting and standing postprostatectomy.

METHODS

Thirty-two men scheduled to undergo a prostatectomy volunteered to participate. Transperineal ultrasound imaging was used to visualize five anatomical pelvic landmarks that have been validated to reflex anatomy and activity of PFMs (pubic symphysis, anorectal junction [ARJ], mid-urethra [MU], bulb of penis [BP], and urethrovesical junction [UVJ]). Both before and after prostatectomy, participants performed three submaximal PFM contractions in sitting and/or standing positions while ultrasound data were recorded.

RESULTS

Postprostatectomy the UVJ location was more caudal and dorsal, the ARJ (puborectalis) vector was longer, the BP was more ventral than preprostatectomy, and these landmarks moved less ventrally with contraction. After prostatectomy, the MU, BP, and ARJ were more ventral in standing than sitting. The UVJ was more caudal and elevated more with contraction in standing than sitting after prostatectomy.

CONCLUSION

These data demonstrate differences in the anatomy and mechanics of PFMs post- versus pre-prostatectomy, and between sitting and standing positions postprostatectomy. Findings are consistent with surgical changes to the bladder and urethral anatomy. Reduced passive support for the urethra and bladder are likely to may contribute to differences between standing and sitting postprostatectomy.