Cystometrogram: the low-cost method for rural areas and its benefits

Abstract

Cystometrography (CMG) is a means of studying bladder pressure. It is a very useful diagnostic tool in patients with lower urinary tract symptoms for which a simple cystoscopy will not offer sufficient information to form a diagnosis. Of the 8893 patients who underwent screening for urological conditions in rural northeast India during 2010–2014, 280 with lower urinary tract symptoms were investigated with a combination of cystoscopy and CMG. By corresponding CMG diagnosis and treatment, we could examine patients’ overall satisfaction with both the procedure and the treatment. We describe a low-cost method of CMG and our results using this method in rural areas of India.

Keywords

Low cost bladder pressure studies

Introduction

Lower urinary tract symptoms alone do not indicate a need for urological surgery. Further investigation of these symptoms is required. While basic cystoscopy may offer insight into the aetiology of a few symptoms (e.g. haematuria caused by bladder cancer), cystometrography (CMG) offers added insight into functional lower urinary tract symptoms (viz. bladder outlet obstruction and neurovesical dysfunction). Interpretation of the CMG may indicate whether surgery would be helpful.

CMG may be performed by introducing two infant feeding tubes into the bladder. One is used for measuring bladder pressure and the other for filling the bladder with fluid. In a normal person, the bladder may be filled to a volume of 300–400 mL without any significant change in overall bladder pressure. Thereafter, there is a mild pressure increase producing a desire to pass urine. The maximum voiding pressure is 60 cm of water in men and 40 cm in women. There should be no significant (<30 mL) post-voiding residual in a normal patient. This is represented by a normal CMG graph (Figure 3).

Where there is abnormal bladder function, for example, in bladder outlet obstruction, with a maximum voiding pressure of >90 cm of water, the chance of developing acute urinary retention is increased. In neurovesicular dysfunction, the bladder wall contracts intermittently thus stimulating the frequency of micturition.

Method

Patients with the following complaints were evaluated with CMG and diagnostic cystoscopy in rural and remote areas of northeast India during diagnostic camps:^1,2 (1) hesitancy, poor stream and sensation of incomplete voiding, urgency, increased frequency, nocturia, dysuria, intermittency and haematuria. An American Urological Association symptom score (assessed by a trained nurse) > 18 warranted evaluation; (2) bladder outflow obstruction suggested by benign prostatic hyperplasia.

Furthermore, follow-up for cases of neurovesical dysfunction and bladder outflow obstruction would routinely include CMG.

Two infant feeding tubes were introduced into the bladder. Through one tube, the bladder was filled with sterile normal saline while the other was used for measuring the bladder pressure (Figures 1 and 2).

Figure 1.

Two infant feeding tubes in the bladder.

Figure 2.

The manometer and the filling.

Figure 3.

Drawing of sample tracing.

Prophylactic antibiotics (1G Ceftriazxone for adults or equivalent third generation cefalosprorin) was given approximately 30 min before the procedure. The patient was requested to void completely before starting the CMG study. The zero level for manometry was chosen as the level of pubic symphysis.

The resting pressure was recorded and the filling started. The filling volume of saline was recorded along with the corresponding pressure were recorded. During the filling phase the following were noted: (1) the volume at which the patient had a first sensation of urine in the bladder and the pressure at that point in time; (2) the volume and pressure at the normal sensation to void; (3) the volume and pressure at the point of urgency; and (4) any unstable contractions or desire to pass urine which fluctuates was noted during the filling phase.

At the point of urgency, bladder filling was halted and the patient asked to void; the maximum voiding pressure was then noted. Once voiding was complete, a post-voiding residual volume was recorded before removing the infant feeding tubes.

Some patients were not able to void in public. Hence the observer was placed behind a curtain. It was sometimes necessary for a patient to stand or squat to encourage the passing of urine. Care was taken in such circumstances to prevent the tubes from falling out.

Diagnostic cystoscopy, usually performed under local anaesthesia, was included in the study protocol as additional information relating to urethral strictures, stress incontinence in women and vesical calculus, and any other abnormalities in the bladder or prostate were thereby identified.

Results

Patients did not usually experience discomfort during the procedure. Those with a urethral stricture were provided sufficient use of lubricant to enable easy insertion of the feeding tubes.

In the diagnostic camps of Samiti for Education, Environment, Health and Social Action (SEESHA) during the five years 2010–2014, 8893 patients were screened in rural and remote areas of northeast India. During these camps, 338 CMGs were carried out.

Patients were classified as not satisfied with the treatment if at the follow-up visit (usually three to six months later) the improvement in symptom score was <20% or side-effects or complications such as stricture formation, haemorrhage, recurrence of symptoms, etc. were identified.

Based on the findings, surgical procedures were carried out as shown in Table 1.

Table 1.

CMG in rural areas.

CMG finding	Surgery carried out/treatment given	n	Not fully satisfied with treatment
Maximum voiding pressure > 90 cm of water	Transurethral vaporisation/resection of prostate	57	1
Inability to pass the catheters or high voiding pressures	Endoscopic internal uretherotomy	7	0
Unstable detrussor contractions, poor compliance, increased voiding pressure, etc.	Cystolitholapaxy	13	0
Stress urinary incontinence	Burch operation	2	0
Unstable detrussor contractions, poor compliance, small capacity bladder, incontinence, etc.	Treatment with anticholinergics, etc.	78	8
Maximum voiding pressure 60–90 cm of water	Medical treatment for bladder outflow obstruction	123	19

Discussion

Without the CMG, some patients with neurovesical dysfunction and many with voiding pressures of 60–90 cm water would possibly have had surgical procedures recommended which would not have given them satisfactory results.

Normal bladder function consists of a filling phase where bladder filling occurs with relatively low pressure increases and an emptying phase requiring coordinated bladder contraction and urethral relaxation, all cerebrally coordinated at the pons. These require a functioning system of afferent nerves, spinal and hypothalamic centres, efferent pathways, and detrusor and sphincter muscles.³ Figure 3 illustrates how normal and abnormal CMG curves appear.

A urodynamic study is an interactive diagnostic study of the lower urinary tract. The American Urological Association has provided guidelines for performing these studies.⁴ However, owing to the high costs of the available testing equipment,⁵ many practitioners treat patients without proper workup. Commercial urodynamic testing may cost in the range of US$400–500.⁶ Such machines have transducers for measuring the pressures, sensors in the rectum to measure the abdominal pressure and computers to do the calculations and present them as a graph.⁷ From these investigations, a maximum voiding pressure of > 90 cm water suggests an obstructed outflow and pressures in the range of 70–90 are considered equivocal.^8,9

The cost of our method is less than US$10 per patient and gives adequately reliable valuable objective information. All patients appreciate the objective evidence offered by the CMG, so this should not be denied them. The results show that most were entirely satisfied with the treatment offered based on the findings. Our follow-up was very satisfactory (248 out of 280) as most patients had no alternate medical care on offer.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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