Dr Sameerkumar Shah, Consultant Radiologist, Founder, Canpic Medical and Education Foundation, Pune, India, explains the usefulness in diagnosis, quantification, classification and follow up of pelvic floor disorders
Pelvic floor disorder affects about 50 per cent of women worldwide in different conditions like physical, psychological, sexual, social, domestic relationships, financial,etc. There is limited knowledge amongst doctors as well, apart from little awareness of pelvic floor health amongst general people. This results in lesser efforts to prevent or treat these disorders. These disorders remain asymptomatic in about 10 – 20 per cent cases.
Why pelvic floor ultrasound?
In the next 30 years, 45 per cent increase in diagnosis and management of pelvic floor disorders is expected and imaging (especially sonography) will play a major role in this. Ultrasound can be helpful in evaluating both men and women with a variety of pelvic floor disorders. Including under-diagnosed disorders like e.g. pudendal canal syndrome. Trans-vaginal and trans-abdominal ultrasound has been used for a long time to visualise the uterus and adnexa for various pathologies like fibroid , ovarian cyst, and endometrioma. Pelvic floor ultrasound helps in visualisation of pelvic floor organs, muscles and other related structures. It is a useful tool for diagnosis, quantification, classification and follow up of pelvic floor disorders. Dynamic and multi-compartmental anatomical and functional assessment is possible with ultrasound.
E.g. assessment of pelvic floor muscle activity plays a major role in urogynaecology. Presence of levator avulsion/injury is a major risk factor for female pelvic organ prolapse and recurrence after surgical correction. This can be diagnosed clinically using vaginal palpation which is subjective, less reproducible, and difficult to teach than imaging methods. Ultrasound plays an important role here.
Ultrasound has many advantages over other imaging modalities like defaecation proctography and defaecation MRI. These include wide availability, intra-operative usage, no radiation, less time consuming, low cost, portability, better evaluation with dynamic studies, easy reproducibility, safety, better visualisation of mesh and implants. Disadvantages of sonography are few and include smaller field of view and operator dependency.
Technique of pelvic floor ultrasound
Study is done after emptying the urinary bladder. Positions used are modified lithotomy , standing or lateral decubitus position. Pelvic floor structures are evaluated at rest and during Valsalva exercise. Precautions are taken to avoid simultaneous levator ani muscle contraction during Valsalva and avoid probe pressure on the introitus allowing the organs free mobility. All types of probes are useful including 2D linear , convex and trans-vaginal probe, 3D convex and trans-vaginal probe. Transperineal, translabial, introital scanning with convex probe is usually done. A radial endocavitary probe with 360° cross-sectional image- for endoanal and endovaginal studies- allows in detail anatomical visualisation of the pelvic floor and provides minute details of levator plate integrity and pelvic organ alignment. All scan planes sagittal ,axial and coronal provide excellent images of various pelvic floor structures like urinary bladder, urethra,vagina,uterus,rectum, anal canal and levator ani muscles.
Indications and clinical impact of pelvic floor ultrasound
Ultrasound allows evaluation of the anterior, middle and posterior pelvic floor compartments. Multi-compartmental assessment is essential for planning the treatment as multiple pathologies often co-exist. Treatment must address all components, failing which results in suboptimal outcomes.
All types of pelvic organ prolapse are diagnosed and quantified using ultrasound. Green classification of cystocele is useful and depends upon the degree of retrovesical angle on Valsalava exercise. Surgical management is different for Green type II and type III cystolceles. This explains high recurrence rate in cases which are managed without considering this important aspect.
Stress urinary incontinence can be easily diagnosed clinically. Urinary bladder neck mobility is well visualised in sonography. It is useful in diagnosing it in situations where it is clinically masked (potential incontinence)with its cause like a pelvic organ prolapse. It’s useful in selecting appropriate site for a sling (TOT or TVT sling ) placement and detecting various complications of a sling like abnormal position, migration, outlet obstruction, urethral erosion and transaction. Under or over correction is possible to assess by studying the shape of the sling. Urinary incontinence after radical prostatectomy in males is studied in a similar way quantifying the bladder neck descent.
Three dimensional ultrasound can diagnose Fowler Syndrome by measuring the volume of the urethral rhabdosphincter in females. Skene’s gland cyst and abscess is visualised excellently.
Various lesions affecting central compartment, apart from organ prolapse are diagnosed, which include Bartholin’s gland cyst and abscess, vaginal inclusion cyst, sebaceous cyst, epidermoid cyst , edema, varicose veins, and tumours like lipoma, fibroma. Lesions like haematocolpos and haematometrocolpos are better evaluated through transperineal approach. Diagnosis of vulval, cervical and lower uterine segment varices during pregnancy is essential and life saving. A caesarean section is planned in advance to avoid post partum haemorrhage which could be torrential and fatal. Pneumovagina(excessive air in vaginal canal) and its etiology like pelvic floor laxity, infectious vaginitis and ano or recto-vaginal fistula are also diagnosed.
Patients who have chronic constipation may have anterior or posterior rectocele, enterocele, recto-enterocele, sigmoidocele, rectal intussusception or anorectal dyssynergia. All are diagnosed, graded and the response to treatment is studied using dynamic sonography.
Cause of faecal incontinence is easily diagnosed and accurate measurements of anal sphincters is possible especially with 360 degree radial endoanal ultrasound probe. The same probe is of immense help to classify and study various types of anal fistula and anorectal abscess. Special anatomical types of fistula like anovaginal and anovulvar fistula are excellently evaluated.
Anal sphincter injuries due to obstetric trauma or any other cause are seen best on 360 degree radial endocavitary probe. Intra-operative study measures the reconstructed sphincter accurately in all three dimensions and is useful to close the surgery after endorsing successful reconstruction. Both endovaginal and endoanal approach provides better results. This prevents re-exploration.
Chronic perineal pain is common and it is difficult to find out the etiology. Sonographic evaluation of muscles here diagnoses the trigger points in myo-fascial pain syndrome. Trigger points are better evaluated using ultrasound elastography with pre and post treatment assessment of the stiffness and size. Pudendal canal syndrome is diagnosed on Colour Doppler evaluation of internal pudendal artery and venous channels. It is quite rewarding to do justice with these patients as this disease is under-diagnosed.
Male and female sexual dysfunction is an area for which ultrasound is underused. Atrophy of superficial perineal muscles — which are best assessed using sonography — could be the etiology of erectile dysfunction in males. An interesting phenomenon known as persistent sexual arousal disorder (PSAD) is seen in females and one of the cause is clitoral and vulval varices — seen on ultrasound — most likely secondary to pelvic congestion syndrome .
Various guided procedures are made easy with ultrasound e.g. pudendal nerve block in pudendal neuralgia, dry needling for trigger points in myo-fascial pain syndrome, etc.
Pelvic floor ultrasound is a simple, inexpensive, useful yet under-utilised tool for diagnosis, quantification, classification and follow up of pelvic floor disorders. Dynamic and multi-compartmental anatomical and functional assessment is possible which avoids exclusion of co-existing disorders. It is justified to suggest pelvic floor sonography in a patient with suspected pelvic floor disorder, considering the several indications and high prevalence. This article is an attempt to create awareness amongst general people as well as medical fraternity, to do justice with patients with pelvic floor disorders.