32 Chapter 4. How to Conduct Urodynamic Studiesdo help to dissect out the relative severity of the differentcomponents in patients with mixed incontinence and thusguide you as to the main thrust of treatment.This is describedin the case history at the end of this chapter.In general, urodynamics are very worthwhile in the follow-ing cases (in descending order):Patients with failed continence surgery need detailed uro-dynamic studies.Patients with symptoms or a past history of voiding difﬁculty(previous prolonged catheter or self-catheterization post-op or postpartum) need voiding cystometry.Patients with mixed symptoms and cystocele who are con-sidering surgery should have detailed urodynamics,possibly with ring pessary in situ (see “Occult” StressIncontinence).Patients with mixed stress and urge leak need cystometryat least, to determine the relative severity of the twoproblems.Patients with pure stress incontinence symptoms who havefailed physiotherapy should have cystometry with someform of imaging, to check whether there is undiagnoseddetrusor overactivity or incomplete emptying.Patients with pure urge symptoms who have failed bladdertraining and anticholinergic therapy should also havecystometry with imaging, to look for an undiagnosedstress incontinence component or incomplete emptying(the latter may be worsened by the anticholinergicdrugs).Different Forms of Urodynamic StudiesThe term “urodynamics” is a general phrase, used to describea group of tests that assess the ﬁlling and voiding phase of themicturition reﬂex, to determine speciﬁc abnormalities.Some of these tests are not “physiological.” For example,inserting catheters into the urethra and a pressure ballooninto the rectum, then expecting the patient to ﬁll and empty
33Different Forms of Urodynamic Studiesas she normally does, may not give a “true” picture of thatwoman’s micturition cycle. Nevertheless, the tests have beenstandardized over the last 40 years, in accordance with theStandardization Committee of the International Conti-nence Society (ICS), and are performed in a similar fashionacross the world. Therefore, abnormalities are interpretedin a standard way and have a common meaning in clinicalpractice.The tests that are generally used include the following:Uroﬂowmetry: Measuring the patient’s ﬂow rate whenvoiding in private, onto a commode that is connected to acollecting device that measures the rate of fall of urine uponthe device.Simple cystometry: Inserting a single catheter into thebladder that measures pressure, with no correction forabdominal pressure, during a ﬁlling cycle, not widely used inthe Western world.Twin channel subtracted cystometry: Inserting a pressurerecording line into the bladder as well as a ﬁlling catheter,along with an abdominal pressure recording line (rectal bal-loon), that records a ﬁlling cycle. The abdominal pressure issubtracted from the bladder pressure to give the detrusorpressure (see Fig. 4.1 and later ﬁgures).Voiding cystometry: The same as twin channel cystometryabove, but the patient is asked to void into a uroﬂow com-mode while the pressure lines are in situ, so that the contrac-tility of the detrusor muscle during the voiding phase ismeasured.Videourodynamics: The same as voiding cystometry above,but radiopaque X-ray contrast dye is used to ﬁll the bladder.The test is done in the X-ray department, and the bladder/urethra is ﬁlmed during cough and other provocation. Inmales, ﬁlming is continued during the voiding phase, but60 % of women are not able to void in these public condi-tions. Post-void ﬁlms are taken to check residual.Voiding cystometry with ultrasound: The same as voidingcystometry, but ultrasound imaging is undertaken duringcough and other provocation, and post-void image is taken.
34 Chapter 4. How to Conduct Urodynamic StudiesUrethral pressure proﬁle: Tests the function of the externalurethral sphincter, performed in selected cases. Similar infor-mation is available from leak point pressure testing.The frequency volume chart and the pad test are also partof urodynamic assessment, but these are discussed in Chap. 5(Outcome Measures).Practical Advice About How to PerformUrodynamic StudiesThis section gives practical advice for a registrar or resident/house ofﬁcer who is newly attached to a urogynecologydepartment. For information about the medical physics of thetests, books by Abrams  or Cardozo and Staskin  arerecommended.FILLINGwarmsterilewaterSubtractionWater Inflow CatheterBladderPressure CatheterTransducerTransducerPvesPabdoRectal Pressure CatheterFigure 4.1 Schematic diagram of twin channel cystometry
35PracticalAdviceAbout How to Perform Urodynamic StudiesCalibration of the EquipmentIn essence, one must check that the equipment is correctlyfunctioning and measures what it is supposed to measure.Calibration of the urine ﬂow machine involves pouring aknown quantity of ﬂuid into the uroﬂow equipment at a rea-sonably slow rate and then checking that the volume pouredin equals the volume measured and that the computer calcu-lated the ﬂow rate correctly.Calibration of the cystometry equipment involves check-ing that a column of ﬂuid 100 cm high yields a pressure read-ing of 100 cmH2O water pressure,then zeroing the transducersto atmospheric pressure (room air) so that zero pressuregives a zero reading. For detailed discussion, see suggestedfurther reading.General Clinical GuidelinesWhen a patient presents for urodynamics studies, you need to“troubleshoot” to make sure that the test can be correctlyperformed on the day.If she has symptoms of acute urinary tract infection (dysu-ria, foul-smelling urine, excessive frequency, strangury, orhematuria), then the test should be postponed, a midstreamurine culture taken,and antibiotics prescribed.This is becauseinstrumentation of the lower urinary tract in the presence ofinfection can cause septicemia.In many units, there is a substantial delay between the ﬁrstvisit date and the date of the urodynamic test. In these cases,you should review the patient’s status quickly before startingthe test.If the patient was given a therapeutic trial of anticholin-ergic therapy at the ﬁrst visit but was not given clear instruc-tions to stop them 1–3 weeks before the test (and is still takingthem), then cystometry may not diagnose detrusor overactiv-ity, so the test may need to be postponed so anticholinergictablets can be stopped.
36 Chapter 4. How to Conduct Urodynamic StudiesIf the patient had mild symptoms and has been attendinga physiotherapist or nurse continence advisor in the mean-time, she may be cured of her incontinence and no longerneed the test.Explaining the Test to the PatientThis is best done by the urodynamics nurse, who must form atrusting relationship with the patient. In our unit, that samenurse may have been involved in taking her initial history orwill often be involved in following up the patient’s responseto treatment subsequently.Urodynamic testing does involve some minor discomfortwith passage of urethral and rectal catheters, but if performedin a digniﬁed and sympathetic manner, most patients say thatit was just slightly uncomfortable. In a teaching unit, only onemedical student should “watch” the procedure. Actually, weask the student to position the lamp, type in data on the com-puter, and help the patient off the couch, so they do not“watch” the patient but are actively involved. Patients do notlike to feel like a goldﬁsh in a bowl, especially when they arebeing asked to leak.Before starting to ﬁll, the nurse or doctor also explains theconcepts of ﬁrst desire to void, strong desire to void, andmaximum cystometric capacity (see below). It is importantfor patients to know we will stop ﬁlling if they have too muchdiscomfort.UroﬂowmetryIdeally, the patient should come to the urodynamics test witha comfortably full bladder, then pass urine in a privateuroﬂowmetry cubicle. Because many patients empty theirbladder just before seeing a doctor, this is not always possible(no matter what letter you send beforehand).A normal urine ﬂow rate (shown in Fig. 4.2) looks like abell-shaped tracing.The maximum ﬂow rate should be at least
37Uroﬂowmetry15 ml/s, but this cannot be judged unless the voided volume isat least 150–200 ml. This is because ﬂow rate depends on thevolume in the bladder. For example, if you drink several pintsof beer, you will pass urine rapidly. If you only drink the occa-sional small cup of tea, your ﬂow rate will trickle out.Other parameters that are measured include the totalduration of ﬂow time to empty the bladder and the averageﬂow rate (i.e., the volume voided divided by the ﬂow time).Typical abnormalities of ﬂow rate in women include inter-mittent prolonged ﬂow rate with evidence of abdominalstraining, suggestive of outﬂow obstruction. This most com-monly occurs after surgery for stress incontinence that hasovercompensated the urethral support. It is also seen inwomen with a cystourethrocele, in which the urethra may bekinked during voiding.Normal values for ﬂow rate in relation to volume voidedhave been derived from a study of several hundred normalwomen (Haylen et al. ; see Fig. 4.3). These “nomograms”Figure 4.2 Normal uroﬂow curve. Maximum ﬂow rate 23 ml/s, aver-age 14 ml/s, voided volume 410 ml/s, ﬂow time 31 s
38 Chapter 4. How to Conduct Urodynamic Studiesallow you to determine what centile of the population apatient’s ﬂow rate represents. Flow rates below the tenthcentile are considered abnormal.The other common abnormality in elderly women is anunderactive detrusor; see Fig. 4.4c.The peak ﬂow rate is poor;15Urineflow(ml/sec)Time (sec)a b cFigure 4.4 (a) Normal. (b) Abdominal straining. (c) Underactivedetrusor (Reprinted with permission from Prolapse and urinaryincontinence. Leader ; Reproduced by permissions of EdwardArnold)70 95th90th75th50th25th10th5th6050403020100VOIDED VOLUME (ml)MAXIMUMURINEFLOWRATE(ml/s)0 100 200 300 400 500 600Figure 4.3 Liverpool nomogram for maximum urine ﬂow rate inwomen
39Uroﬂowmetrythe average ﬂow rate is poor, but there is no evidence ofabdominal straining. The detrusor contraction is intrinsicallyweak, but this needs to be proven by voiding cystometry.Less common voiding abnormalities are described in thesection on voiding cystometry (detrusor hyperactivity withimpaired contractility, DHIC, seen in the elderly with mildneurological dysfunction and detrusor sphincter dyssynergia,seen only in neuropathic disease such as multiple sclerosis).After uroﬂowmetry, residual urine volume is measuredeither by catheterization, if the patient is about to undergocystometry, or by ultrasound.A simple “bladder scan” (Bard)may be used, which automatically calculates the residual vol-ume. Alternatively, standard transabdominal or trans-vaginalultrasound is used to measure the residual volume, and for-mulae that calculate the volume of a sphere are then used bythe clinician to calculate the residual amount (e.g.,width×depth×height×0.7).Performance of CystometryTo pass the bladder catheters, the urethra is cleansed withsterile saline; a sterile drape is placed around the urethra;Lignocaine gel is applied to the urethra, then the ﬁlling lineand the pressure recording line (similar to a central venouspressure manometry line) are inserted into the urethra.Usually, the manometry line is inserted into the distal cathe-ter hole, so the patient only feels one line going into the ure-thra, then the manometry line is disconnected from the ﬁllingline by pulling it backward slightly once it is in the bladder.The vesical pressure line is then attached to the domed trans-ducer unit, which feeds into the software of the urodynamicequipment. See Fig. 4.5.Some units employ a catheter that has a micro-tip pressuretransducer embedded into the distal end, so that an externaltransducer is not needed and the slight artifactual delayencountered in the ﬂuid-ﬁlled system is avoided. Such micro-tip transducer catheters are quite costly (1,500–1,800 Eurosper catheter) and are quite delicate, so they may last roughly
40 Chapter 4. How to Conduct Urodynamic Studies6 months to 2 years of normal use. The ﬂuid-ﬁlled pressurerecording lines are single-use items, costing a few Euros perset. Each unit makes its own decision about which cathetertype to use, generally on the basis of cost.Passing the Rectal CatheterThe very small rectal balloon/transducer catheter is attached tothe abdominal pressure recording line (usually prepackaged bythe manufacturer).The balloon is coated in sterile lubricant,thenplaced into the rectum. One should not push the ﬁnger into thepatient’s rectum; this is unpleasant and unnecessary. Just gentlyinsert the balloon about 3 cm into the rectal ampulla.As an alter-native, a vaginal balloon may also be used to record intravaginalFigure 4.5 Bladder ﬁlling line, vesical pressure line, and rectal bal-loon
41Twin Channel Cystometrypressure which is equivalent, but this is usually not successful inparous women as the balloon slips out in the erect position.Twin Channel CystometryAfter connecting the bladder pressure recording line and theabdominal pressure recording line to the transducer domes,insert ﬂuid into the line to exclude air bubbles, then zero therecording pressure using the software of the urodynamic pro-gram. The software program will subtract the abdominalpressure (Pabdo) from the vesical pressure (Pves) to yieldthe true detrusor pressure (Pdet).The bladder is then ﬁlled with warm sterile water. Mediumﬁlling rate (10–100 ml) is advised in nonneuropathic patients.Generally a rate of 50–75 ml is used, via a peristaltic pump toprevent backﬂow into the bladder during a rise in detrusorpressure. The following parameters are important in a fullurodynamic report:Results of free uroﬂowmetry if available.Initial residual urine volume (after the patient has per-formed free uroﬂowmetry)—normal residual=less than50 ml.Whether pain or resistance to catheterization is noted(may suggest urethral stenosis).The ﬁrst desire to void, when patient ﬁrst notes that shewould look for a toilet—normal FDV=150–200 ml.Normal desire, when patient would normally stop workand go to toilet—normal desire usually=350–400 ml.Maximum cystometric capacity, when patient would nottolerate any more ﬂuid. Although the patient shouldnot be pushed to the point of bladder pain, we use theexample that if she were driving in the country, shewould get out of her car and go behind the bushes tovoid—normal MCC=450–500 ml.The ﬁlling line is then removed (because it has a diametersufﬁcient to obstruct the outﬂow of urine during thenext steps).
42 Chapter 4. How to Conduct Urodynamic StudiesA supine cough is performed, while the urethra is visuallyinspected to look for a stress leak. Reassure the patientthat there is only sterile water in the bladder and thatall linen is discarded after each test, so her leaking willnot spoil the linen. At this point, a cough-provokeddetrusor contraction may be seen.Supine tap water provocation is performed, while asking ifurgency is increased by the sound of running water (andrise in detrusor pressure is checked for).The patient then stands erect.The transducer levels are readjusted so that they remain atthe level of the symphysis pubis (e.g., raise them for atall patient).Erect tap water stimulus is performed (as for supine).Erect cough is performed, with the legs widely apart.Reassure the patient again that if any ﬂuid escapes, it isonly sterile water; there is no urine in the bladder, andthis is an important part of the test.The patient then sits down on the uroﬂow commode; thetransducers are lowered so they remain at the symphy-sis pubis, and voiding cystometry commences.Urodynamic Diagnoses Availablefrom the Filling PhaseThe diagnoses that may be made during the ﬁlling phaseAbrams et al.  are as follows:Urodynamic stress incontinence (USI) is the involuntaryleakage of ﬂuid during increased abdominal pressure, in theabsence of a detrusor contraction (Fig. 4.6).Detrusor overactivity is a urodynamics observation charac-terized by involuntary detrusor contractions during the ﬁllingphase which may be spontaneous or provoked.The most com-mon picture is that of systolic detrusor pressure waves, seenduring the ﬁlling phase (Fig. 4.7). The same picture is seenwhen the sound of running tap water provokes a detrusorcontraction.
43Urodynamic Diagnoses Available from the Filling PhaseA less well-understood phenomenon is detrusor overactiv-ity seen as a gradual linear rise in bladder pressure (Fig. 4.8)that persists after ﬁlling stops, in association with urgency.This is often termed “low compliance DO.”Finally, two less common but important variants of systolicoveractivity are cough-provoked DO and erect-provokedDO. Cough-provoked DO is usually quite clearly seen on thetracing (Fig. 4.9).But erect-provoked DO often needs careful scrutiny toexclude artifact. A common problem is that the abdominalpressure transducer is not readjusted when the patient standsup (it is not repositioned to the level of the pubic symphysis).If a short patient stands up from the table, her pubic bonemay drop to well below its original site when she was lying onFDVSDVMAX CAP150300leak450FillingVolumemlsmls/seccmH2OcmH2OcmH2OPvesPabdoPdetVolVoided50025006040200604020060402006040200Figure 4.6 Urodynamic stress incontinence, with a normal FDV,SDV, and MCC, no detrusor contractions (Pves and Pdet remainﬂat) but obvious leak of ﬂuid with cough
44 Chapter 4. How to Conduct Urodynamic Studiesthe couch; Pabdo then becomes negative. Because Pvesminus Pabdo equals Pdet, if you subtract a falsely negativePabdo, you will get a falsely positive Pdet when the patientstands (see Fig. 4.18 given as part of the case history at end ofthis chapter).What Is Sensory Urgency, Now Termed BladderOversensitivity?For many years, patients who suffered from frequency,urgency, and nocturia, in whom urodynamic testing revealeda stable bladder but a very early ﬁrst desire to void (less than100–150 ml) and a small maximum cystometric capacity (lessthan 400 ml), were diagnosed as having sensory urgencyJarvis . These patients often found bladder ﬁlling undulyFDVMAX CAPleakCoughFillingVolumemlsmls/seccmH2OcmH2OcmH2OPvesPabdoPdetVolVoided50025006040200604020060402006040200Figure 4.7 Detrusor overactivity with systolic waves of detrusorcontractions, seen at FDV and at MCC. Stress leak does not occur
45Urodynamic Diagnoses Available from the Filling Phaseuncomfortable. More recently, the International ContinenceSociety has termed such patients as being on the mild end ofthe spectrum of “bladder pain syndrome.” The severe end ofthe spectrum is frank interstitial cystitis (see Chap. 12, thesepatients mainly complain of suprapubic pain).The milder endof the spectrum is now called bladder oversensitivity.A problem arises in that repeat twin channel cystometry(and ambulatory cystometry, a research tool) will revealdetrusor overactivity in at least one third of cases of “sensoryurgency.”The management of patients with a small capacity stablebladder is therefore usually empirical. One starts out treatingas for detrusor overactivity, because they do meet the clinicalmlsmls/secleakFDVMAX CAP120280cmH2OcmH2OcmH2O50025006040200604020060402006040200FillingPvesPabdoPdetVol.VoidedVolumeFigure 4.8 Low compliance detrusor overactivity
46 Chapter 4. How to Conduct Urodynamic Studiescriteria for the symptom complex of overactive bladder. Ifthe patient does not respond, then cystoscopy to look forfeatures of interstitial cystitis is reasonable. This area iscontroversial.Features of the Atonic BladderDuring the Filling PhasePatients with a very late FDV (more than 400–500 ml) and avery large MCC (more than 650–750 ml) have characteristicsof an atonic bladder, but this condition should not really bediagnosed until voiding cystometry has been performed, toprove that the detrusor is underactive.Before going on to describe voiding cystometry, a sum-mary of videourodynamic testing and twin channel cystometrywith ultrasound imaging is given.500250FillingPvesPabdoPdetmls/secFlow RateVolumemlsFDVMax capleak06040200604020060402006040200Figure 4.9 Cough-provoked detrusor overactivity
47VideourodynamicsVideourodynamicsVideourodynamic TestingThis involves installation of a radiopaque dye (e.g., Hypaque)dissolved in warm water, while screening intermittently usinga ﬂuoroscopy unit with image intensiﬁer in the radiologydepartment. A ﬂuoroscopy table that rises to the erect posi-tion is needed, with a platform on the bottom of the table, sothat the erect patient can turn to the side for ﬁlming of thelateral view of the bladder neck and urethra (see Fig. 4.10).This study is termed videocystourethrography (VCU) where avideotape can be made of the screening images that mostsoftware packages can superimpose upon the cystometrytracing and store for later review.Because VCU involves exposure to X-ray and installationof iodine-containing medium which patients may be allergicto, not to mention the costs of using the ﬂuoroscopy unit, it isonly needed in selected cases.Figure 4.10 Patient in erect position during screening on videocys-tourethrography
48 Chapter 4. How to Conduct Urodynamic StudiesVCU was the initial “gold-standard” urodynamics test andis still important for male patients in whom prostatic outﬂowobstruction needs to be delineated from simple detrusoroveractivity. In men, the voiding phase is always screened.Also, in men with neurogenic incontinence, VCU allowsclearer deﬁnition of any contribution from prostatic outﬂowobstruction. Finally, VCU allows detection of vesicouretericreﬂux which may threaten the upper urinary tract.In the female, studies have shown that about 60 % ofwomen cannot void in the upright position on a screeningtable with a collecting funnel between their legs.During a cough, the bladder neck may be slightly open,forming the shape of a bird’s beak, with ﬂuid entering theproximal urethra (called “beaking”; see Fig. 4.11). In moresevere cases, the urethra may open widely in the shape of afunnel during cough (called “funneling”). In the worst-casescenario, as soon as the patient stands, the bladder funnelsopen widely, and ﬂuid pours out onto the ﬂoor. TheseFigure 4.11 “Beaking” on VCU
49“Occult” Stress Incontinenceﬁndings have been classiﬁed using various grading systemsHerschorn .VCU is very helpful in women with failed previous conti-nence surgery. In the anteroposterior view, typical features ofprevious colposuspension or sling can be seen, with slightly“dog-ear”-shaped indentation just lateral to the bladderneck. Sometimes although these lateral indentations arepartly evident, the urethrovesical junction may still be hyper-mobile on the lateral view, suggesting that the sutures are nolonger effective.The patient in Fig. 4.11 had undergone Macroplastiqueinjections to the midurethra, which explains the slightlyasymmetrical picture of the “beak.”In other cases, the sutures are very evident; the bladderneck does not open appreciably, but ﬂuid still leaks out. Thisis typically suggestive of intrinsic sphincteric deﬁciency; thatis, the urethral musculature is intrinsically weak. Many clini-cians would seek to quantify this by performing an abdomi-nal leak point pressure or a urethral pressure proﬁle (seebelow).Value of VCU in CystoceleIn patients symptomatic of cystocele (often worse at the endof the day, not when you examine them in the morningclinic), a cystocele may be very evident in the erect positionwith a full bladder that was not clearly seen when examinedin the supine position. At the end of the voiding phase, youmay also see urine trapping in the cystocele (when screeningin the erect position to check post-void residual; seeFig. 4.12).“Occult” Stress IncontinenceOne problem in urogynecology is that a patient with cysto-cele but no appreciable incontinence may begin leaking afteran anterior repair. This is because the cystocele may involve
50 Chapter 4. How to Conduct Urodynamic Studiesthe upper portion of the urethra, so when the cystoceledescends during cough, the urethra is kinked off, masking theincipient incontinence. It is very disturbing when the patientcomes to the postoperative visit complaining of stress incon-tinence for the ﬁrst time. This is known as “occult” stressincontinence. The likelihood of this occurring ranges from 7to 28 %, depending upon the publication (for review, seeHaessler et al. ).Such patients may have to replace their cystocele manu-ally before they can have a good stream of urine. If they donot digitate the cystocele, they can have initial hesitancy, needto strain to start, and have terminal dribble. In such cases, it isFigure 4.12 Urine trapping in a dependant cystocele after voiding
51Ultrasoundworthwhile to conduct VCU (or twin channel cystometry)with a ring pessary in situ, as this is likely to unmask theoccult incontinence. This allows one to incorporate a speciﬁcprocedure for incontinence into the repair operation (forexample see Schierlitz et al. ).UltrasoundBecause of the costs and X-ray exposure involved with VCU,ultrasound imaging has become popular as part of urody-namic testing.Initially, ultrasound imaging of the pelvis used transab-dominal scanning which gave poor deﬁnition of the bladderneck. The next step was to use trans-vaginal scanning, whichallowed better deﬁnition of the bladder neck but could not beperformed during a stress provocation test (because the vagi-nal probe interfered with urethral leakage). In the lastdecade, trans-perineal scanning has allowed good visualiza-tion of the bladder neck. See Fig. 4.13. Using this technique,one can assess the following:Hypermobility of the bladder neck regionFluid in the proximal urethra (Fig. 4.13)Beaking and funneling of the urethraThe main difﬁculties are that:Ultrasound scanning is not easy to perform in the erectposition.Trans-perineal scanning does not easily yield a lateralview that is helpful in previous failed continencesurgery.Therefore, trans-perineal scanning occupies an intermedi-ate position in terms of accurate anatomical assessment ofcomplex incontinence (somewhere between simple “eyeball-ing” of leakage on twin channel cystometry and full radio-logical imaging with VCU).
52 Chapter 4. How to Conduct Urodynamic StudiesabFigure 4.13 Determination of bladder neck descent and retrovesi-cal angle: ultrasound images show the midsagittal plane at rest (a)and on Valsalva (b). S symphysis pubis, U urethra, B bladder, Ututerus, V vagina, A anal canal, R rectal ampulla, L levator ani (From:Dietz , with permission)
53Voiding CystometryVoiding CystometryDuring voiding cystometry, the patient sits on the uroﬂowcommode with the pressure transducers in situ.All staff leavethe room while she voids in private (Fig. 4.14).The maximumand average ﬂow rates (Q Max and Q Ave) are measured, asin a free uroﬂow, but the maximum detrusor pressure at thepoint of maximum ﬂow (Pdet at Q Max) is also measured.The ﬁndings may be as follows.Figure 4.14 Voiding cystometry
54 Chapter 4. How to Conduct Urodynamic StudiesIn outﬂow obstruction, Q Max and Q Ave are low, but thedetrusor pressure is high (the detrusor is trying to overcomethe obstruction, so Pdet at Q Max is high, called “high pres-sure, low ﬂow”).Also in outﬂow obstruction, abdominal straining may beseen on Pabdo channel.In an underactive detrusor, the Q Max and Q Ave are low,but the detrusor pressure at Q Max is also low (called “lowpressure, low ﬂow”), which is a feature of the atonic bladder.Diagnoses Made After Voiding CystometryOutﬂow ObstructionIn women, the most common cause of obstruction is previouscontinence surgery or prolapse kinking the urethra (seeFig. 4.15).The high detrusor pressure with the low ﬂow rate istypical. If sufﬁcient voiding efﬁciency can be generated (oftenwith abdominal straining, giving an intermittent pattern),then the residual may be minimal.Atonic BladderAs mentioned, some features of bladder atony (large volumeat FDV and MCC) are seen during ﬁlling, but during voiding,the most important feature emerges, of low detrusor pressurewith low ﬂow rate. Generally, there is a substantial residual.In women, this may be seen with diabetic autonomic neu-ropathy, or it may be a marker of a neurological lesion at thelevel of the sacral cord.Detrusor Hyperactivity with ImpairedContractility (DHIC)This is another cause of an underactive detrusor in elderlywomen. During the ﬁlling phase, there may be mild detrusoroveractivity (see Fig. 4.16). During voiding, there is an initial
55Voiding CystometryH:VfillF:PabdE:PvesE-F:PdetB:VvoidA:QvuoidmlcmH2OcmH2OcmH2Omlml.sec-170060050040015:50 16:40300200100-20-200020204060806040-20020602004006001020304040Figure 4.15 Obstructed voiding pattern on voiding cystometry.Note detrusor contracting vigorously, then abdominal strainingadded, to achieve bladder emptying.Although ﬂow was intermittentand prolonged, the residual was 90 ml (Qvoid=ﬂow rate, ml/s)
56 Chapter 4. How to Conduct Urodynamic Studiesburst of detrusor activity at the start of ﬂow (detrusor hyper-activity), but it is not sustained through the whole ﬂow(impaired contractility). This condition is thought to be dueto atherosclerotic changes of the blood vessels supplying thespinal cord, so that there is relative impairment of the coor-dination of the micturition reﬂex Resnick and Yalla .Detrusor Sphincter Dyssynergia (DSD)In women with multiple sclerosis or spinal cord injury, you maysee severe detrusor overactivity during the ﬁlling phase, thenduring voiding,very high detrusor pressures and an intermittentﬂow rate without abdominal straining,due to intermittent spasmof the urethra. It is due to poor coordination of the spinal relaysmlsmls/secleakFDVMAX CAP300480cmH2OcmH2OcmH2O50025006040200604020060402006040200FillingPvesPabdoPdetVol.VoidedVolumeFigure 4.16 Detrusor hyperactivity with impaired contractility. Notedetrusor overactivity during ﬁlling phase, but poorly sustained con-tractility during voiding. Q Max 8 ml/s, Q Ave 3.5 ml/s, and residualvolume was 120 ml
57Special Urodynamic Testsof the impulses that signal the command to void. These shouldevoke synchronous relaxation of the urethra with contraction ofthe detrusor,but in DSD the synchrony is impaired due to spinalcord pathology (for review, see Jung and Chancellor ).Special Urodynamic TestsUrethral Pressure ProﬁlometryWith about 200 ml ﬂuid in the bladder, a double lumenﬂuid-ﬁlled manometry catheter or a ﬂexible micro-tippedpressure recording catheter with one transducer mountedat the end and one 6 cm along is withdrawn from the blad-der into the urethra. A mechanical puller device is used sothat withdrawal occurs at about 5–10 cm/min. First, a restingurethral pressure proﬁle (UPP) is made, to record the rise inpressure as the catheter at the 6 cm position passes throughthe urethral sphincter area. See Fig. 4.17. The urethral clo-sure pressure equals urethral pressure (Pura) minus thebladder pressure (Pves). In a continent woman, Puraexceeds Pves. In most continent women, the urethral clo-sure pressure is greater than 60 cmH2O pressure (althoughthe UPP has been criticized because there is no absolutecutoff between continence and incontinence for this test).Aresting closure pressure of less than 20 cmH2O is consid-ered very low and is one indicator of intrinsic sphinctericdeﬁciency (ISD).Next, the catheter is reinserted into the bladder and with-drawn through the urethra while the patient gives a series ofshort hard coughs (a stress UPP). Even while coughing, Purashould exceed Pves. In the incontinent woman, the Pvesrepeatedly exceeds the Pura during the cough, yielding a“negative stress proﬁle.”Abdominal or Valsalva Leak Point Pressure TestAt a volume of 200–250 ml, with a simple manometry linein the bladder (as for cystometry setup), the patient is
58 Chapter 4. How to Conduct Urodynamic Studiesasked to give a series of progressively harder coughs orValsalva maneuvers. The intravesical pressure required toproduce leakage from the external meatus (in the absenceof a detrusor contraction) is called the leak point pressure(LPP). An LPP of less than 60 cm is thought to indicateintrinsic sphincteric deﬁciency: 60–100 cmH2O is equivocal,and a pressure of more than 100 cm is often taken to indi-cate that the leak is due to urethral hypermobility. The testD-E:PucD-E:PuraE:Pves12.7.11UPP12/7/11 9:31.cmH2O1:05.5MUCP23CM1*cmH2OcmH2O020406080-20-200 1:15 1:401020406080-20020406080Figure 4.17 Urethral pressure proﬁle test in stress incontinence
59Special Urodynamic Testsis controversial because test–retest reliability has beendifﬁcult to document and correlation with other measuresof incontinence severity is not high.Triple Lumen (Trantner) Catheter Test for UrethralDiverticulum, Now Replaced by MRIThe triple lumen catheter test, with radiological screening,was previously the standard test for diagnosis of urethraldiverticulum. The catheter had two balloons; the smaller bal-loon was ﬁlled with 8 ml water and compressed gently againstthe internal urethral meatus. The larger balloon was ﬁlledwith 20 ml of water and compressed against the external ure-thral meatus, so that ﬂuid could not escape the urethra.Radiopaque dye injected into the urethra would be forcedinto the urethral diverticulum, thus delineating it on X-rayscreening.In the last 5 years, urogynecological MRI and ultrasoundimaging have improved, so that these are the preferred diag-nostic test for detection of urethral diverticulum.See Fig.4.18,for ultrasound image of diverticulum.Although excluding the diagnosis of urethral diverticu-lum is an important part of urogynecology investigation, thecondition is not commonly encountered (about 3 % ofwomen with recurrent UTI and post-micturition dribbling).Therefore, it is not further discussed in this “practical” text(but see Nichols and Randall  or Cardozo  for fullreview).Note Regarding Diagnostic Testsfor Vesicovaginal FistulaeBecause vesicovaginal ﬁstulae are not common in theWesternworld, details of diagnosis and management are outside thescope of this text. For full review, see Hilton .
60 Chapter 4. How to Conduct Urodynamic StudiesExample of ReportCase History, with Example of a Full UrodynamicReport, Illustrating Contribution of UrodynamicStudies to ManagementMrs. Brown is a 47-year-old para 2+0 lady. Twelve years ago,after her second delivery (Kielland’s forceps), she notedleakage with standing up from the sitting position, with mixedFigure 4.18 MRI of urethral diverticulum (arrow)
61Example of Reportstress and urge incontinence.She had twin channel cystometryelsewhere; results are lost. Afterward, she was given 6 weeksof Ditropan 5 mg TDS, which she did not tolerate because ofdry mouth. Pelvic ﬂoor physiotherapy was not performed. Shetold the doctor she did not want any more tablets but wouldlike an operation. She underwent a colposuspension and wenthome with a suprapubic catheter for 10 days.She was dry for about 2 years but did notice persistentdaytime urge with nocturia. Since then, she has had graduallyincreasing leakage when arising from a sitting position. Sheoften has to go back to the toilet to revoid.On examination, with bladder partly full, stress leak is notseen.The anterior vaginal wall is not hypermobile.The retro-pubic area is rather ﬁxed to the back of the pubic bone, moreso on the left than the right. She had a weak 2-s pelvic ﬂoorcontraction.Summary, provisional diagnosis: This patient may havefailed continence surgery with recurrent stress leak, or shemay have an overactive bladder, or she may have both.Obstruction is also a possibility to explain her need to revoid.Clearly, careful urodynamics are essential.Urodynamic ResultInitial Residual: 90 ml. First desire to void=190 ml. Strongdesire to void=230 ml. Maximum capacity=380 ml.During ﬁlling phase, systolic detrusor contractions wereseen, Max P det of 21 cm. Supine tap water=increase in Pdet to28 cmH2O. Supine cough=no stress leak. Erect provoca-tion=increased detrusor pressure to Pdet 35 cmH2O with leak.During multiple erect coughs, the patient leaked a smallamount of ﬂuid; on screening, asymmetrical beaking of thebladder neck was seen, with ﬂuid leak.In lateral view, the bladder neck did not descend.Voiding cystometry—Q Max 25 ml/s; Q Ave 9 ml/s. Flowrate was intermittent and prolonged, with abdominal strain-ing. Pdet at Q Max was 45 cmH2O; ﬁnal residual was 110 ml.See Fig. 4.19
62 Chapter 4. How to Conduct Urodynamic StudiesCommentsMrs. Brown has a reduced bladder capacity (380 ml), withdetrusor contractions provoked by ﬁlling, supine tap water,and erect provocation to a maximum of 38. She does havesome stress incontinence with an asymmetrical appearance ofthe urethra, in keeping with ﬁndings on examining the retro-pubic vagina. Her maximum ﬂow rate is ﬁne, but her averageﬂow rate is poor, with abdominal straining suggesting relativeoutﬂow obstruction, in keeping with initial and ﬁnal residualsof 90 ml/110 ml.mlsmls/secFDVMAX CAP190380cmH2OSupinetapwaterSupineCoughErectpositioncommencesErectprovokedD.O.Erectcoughstressleakintermittentprolongedflow withAbdominalstratiningcmH2OcmH2O50025006040200604020060402006040200FillingPvesPabdoPdetFlowVoidedVolumeFigure 4.19 Urodynamic study of Mrs. Brown
63ReferencesDiagnosis: Marked Detrusor Overactivity (DO)with Mild Degree of Obstruction; Mild StressIncontinence ManagementTreat the DO with bladder training, including pelvic ﬂoormuscle physiotherapy.Teach double emptying techniques.At6 weeks, start anticholinergics, for example, tolterodine (lessdry mouth), but recheck post-void residual 6 weeks later.If increased, you may need to consider clean intermittentself-catheterization. After this therapy, if stress incontinencepersists, consider collagen/Macroplastique.Note: If this patient had undergone pelvic ﬂoor traininginitially, with alternative anticholinergic therapy, the currentsituation may not have arisen.ConclusionsUrodynamic testing requires careful attention to detail, bothin the selection and counseling of the patient during the test,in performance of the provocation maneuvers, and in analysisof the results, to obtain precise diagnoses of the componentsof the continence disorder. Unlike an ECG that can be per-formed by a technician, this test requires a trained clinician inorder to yield the maximum information.References1. Abrams P. Urodynamics. 3rd ed. London: Springer; 2006.2. Abrams P, Cardozo L, Fall M, Grifﬁths D, Rosier P, Ulmsten U, et al.The standardisation of terminology of lower urinary tract function:report from the standardisation Sub-committee of the InternationalContinence Society. Neurourol Urodyn. 2002;21:167–78.3. Cardozo L. Urethral problems. In: Urogynaecology. New York:Churchill Livingstone; 1997. p. 377–86. Chapter 24.4. Cardozo L, Staskin D, editors. Textbook of female urology andurogynaecology. Thirdth ed. London: Martin Dunitz; 2010. p. 257–304. Chapters 29–32.5. Dietz HP. Pelvic ﬂoor imaging in incontinence: what’s in it for thesurgeon? Int Urogynecol J. 2011. doi:10.1007/s00192-011-1402-7.
64 Chapter 4. How to Conduct Urodynamic Studies6. Haessler AL, Lin LL, Ho MH, Betson LH, Bhatia NN. Reevaluatingoccult incontinence. Curr Opin Obstet Gynecol. 2005;17:535–40.7. Haylen BT,Ashby D, Sutherst JR, et al. Maximum and average urineﬂow rates in normal male and female populations – the Liverpoolnomograms. Br J Urol. 1989;64:30–8.8. Herschorn S. Videourodynamics. In: Cardozo L, Staskin D, editors.Textbook of female urology and urogynaecology. London: MartinDunitz; 2001. p. 264–74. Chapter 24.9. Hilton P. Surgical ﬁstulae and obstetric ﬁstulae. In: Cardozo L,Staskin D, editors. Textbook of female urology and urogynaecology.London: Martin Dunitz; 2001. p. 691–720. Chapters 55, 56.10. Jarvis GJ. The management of urinary incontinence due to primaryvesical sensory urgency by bladder drill. Br J Urol. 1982;54:374–6.11. Jung SY, Chancellor MB. Neurological disorders. In: Cardozo L,Staskin D, editors. Textbook of female urology and urogynaecology.London: Martin Dunitz; 2001. p. 837–53. Chapter 65.12. Leader LR, et al. Handbook of obstetrics and gynaecology. 4th ed.London: Chapman & Hall; 1996. p. 406.13. Nichols DH, Randall CL. Urethral diverticulum and ﬁstulae. In:Vaginal surgery. 4th ed. Baltimore: Williams and Wilkins; 1996.p. 422–5. Chapter 18.14. Resnick NM, Yalla SV. Detrusor hyperactivity with impairedcontractile function: an unrecognized but common cause of inconti-nence in elderly patients. JAMA. 1987;257:3076–81.15. Schierlitz L, Dwyer P, Rosamilia A, Murray C, Thomas E, FitzgeraldE, Hiscock R, De Souza A. A prospective randomised controlledtrial comparing vaginal prolapse repair with and without tensionfree vaginal tape (TVT) in women with severe genital prolapse andoccult stress incontinence: long term follow up. Int UrogynecolJ. 2010;21(Suppl):S2–3.