Urinalysis and urine culture (if appropriate) are an integrated part of basic neurourological evaluation. If not already done by the referring physician, they should be performed as soon as reasonably possible, as SCI patients are at risk of urinary tract infection (UTI) and bacterial colonization, potentially contributing to the clinical presentation of patient’s overall condition. Furthermore, reported symptoms may not clearly indicate the presence of UTI [1].

Urine analysis may reveal leukocyturia, proteinuria, glycosuria, or hematuria, indicating relevant comorbidities or complications of NB requiring further assessment. Negative results for nitrite and leucocyte esterase in reagent strip (dipstick) analysis or absence of pyuria/bacteriuria on microscopic examination reliably exclude UTI in people without additional risk factors for infections of uncommon etiology [2]. As NB patients may be colonized by strains of resistant bacteria, a dipstick test may be more useful to exclude than to prove urinary tract infection in SCI patients [3]. Thus, urine culture with antibiotic sensitivity should be performed when any evidence of infection is detected [4, 5]. Physicians should also be aware that due to bacterial colonization, urine dipstick testing and bacterial culture may sometimes be unreliable for diagnosing active infection [6]. Of note, asymptomatic bacteriuria (>10⁵ CFU/mL), highly prevalent in individuals with SCI and NB, in older persons, and in diabetic and catheterized patients, should not be routinely treated except in pregnant women and before urological procedures within the urinary tract [7–9].

The interpretation of obtained results should also analyze bladder-emptying technique and the presence of an indwelling catheter [10]. The results should be interpreted in the context of previous urological history and treatment, as well as presence of confounding diseases and/or comorbidities. Appropriate urine samples include clean-catch midstream samples , samples taken from a freshly inserted intermittent sterile catheter, and samples taken from a catheter port [6]. Samples from leg bags should not be analyzed.

Blood tests allow physicians to assess the patient’s general condition, kidney function, and the presence of systemic inflammation [11, 12]. As patients after SCI are at higher risk of developing renal failure than individuals suffering from non-traumatic NB , measurement of serum creatinine levels and calculation of glomerular filtration rate (GFR) is significantly useful in the baseline evaluation of overall kidney function [13]. Of note, in patients after SCI who may be characterized by low muscle mass, lower upper limits for normal range of creatinine values are appropriate [14]. The blood urea nitrogen (BUN test) , along with the creatinine test , also helps to assess renal function and diagnose kidney disease. Electrolyte disorders described as abnormalities in levels of potassium, sodium, chloride, bicarbonate, phosphate, magnesium, and calcium may indicate advanced stages of renal failure [15].

The voiding diary is a simple, non-invasive method to semi-objectively quantify voiding behavior and fluid intake habits. The International Consultation on Incontinence describes three variants of voiding diaries [16]:

There is a paucity of studies evaluating optimal diary duration in patients with neurogenic lower urinary tract dysfunction [14, 17]. Nevertheless, data from studies investigating diary duration in patients with idiopathic overactive bladder stress that a voiding diary observation with 3–7 days duration should be recommended [18]. Researchers agree that the precision of data obtained from the diary is proportional to its length in days. However, opposite correlation exists between the length of the diary and the patient’s compliance with its completion. Patients should be motivated by clinicians to faithfully conduct the test.

To date no consensus exists on reference values for voiding diary parameters, as all of these quantities are strongly influenced by multiple factors [19]. Patients might also modify their behavior to obtain optimal results, leading to invalidation of the test. Nonetheless, the voiding diary still supports clinicians in their day-to-day clinical practice. It has been shown that more than 50% of patients may overestimate daytime urinary frequency when comparing subjective symptoms to objective findings obtained from bladder diaries [20]. The voiding diary also helps to identify polyuria and nocturnal polyuria as well as to calculate 24-h and nocturnal total urine volume [14]. Divergence between diary recordings and the patient’s rating of symptoms can be useful in patient counselling [20–23]. The bladder diary might help to identify dietary bladder irritants, abnormal voiding intervals, and abnormal volume intake. Presented factors can be successfully treated with behavioral and lifestyle changes [24]. The voiding diary can also be used to follow the effectiveness of treatment. Comparison of the first diary with subsequent records can help in quantifying the success of therapy. The voiding diary can help to properly conduct future urodynamic study. Decreased filling rates should be considered in patients who show low urine volumes during each void or catheterization, as well as consistent leakage between each micturition [25]. The accurate record of diary variables can allow for estimation of functional bladder capacity and may help to reveal variations in voided volumes, indicating detrusor overactivity [26].

Note that estimation of functional bladder capacity from voided volume is usually limited to patients with neurogenic detrusor overactivity. In those suffering from neurogenic detrusor underactivity or detrusor-sphincter dyssynergia, who usually present with elevated post-void residual or retention, the catheterization diary should be implemented [19]. It is used in the same manner as the voiding diary. Recorded parameters include time and volume of urine obtained at catheterization, as well as the same values obtained for any voids between catheterizations. When sensation is preserved, episodes of urgency may also be noted. Obtained quantities may help in the estimation of urodynamic results. When catheterization volumes exceed the volume at which filling pressures become unsafe for the upper urinary tract, appropriate management needs to be implemented [19]. The catheterization diary may also help to answer the question whether a full bladder elicits sensation in the patient. Moreover, careful record of catheterizations can show fluctuations in diuresis and could be used to determine the optimal catheterization frequency to adopt [10].

Concluding, although there is a paucity of reliable data investigating the usefulness of voiding diaries in neurologically impaired patients, it should be included in the initial patient’s evaluation as a diagnostic, management and outcomes assessment tool.

Post-void residual (PVR) urine volume should be assessed during the first appointment of SCI patients suffering from neurogenic lower urinary tract dysfunction. Where the bladder fails to empty completely, PVR is elevated and may predispose to incontinence, UTIs, bladder stones , and renal dysfunction [14]. An elevated PVR indicates dysfunctional voiding, but it cannot be used to discern whether this is caused by poor detrusor contractility (underactive detrusor) or by obstruction (detrusor-sphincter dyssynergia). However, measurement of PVR during the first appointment may detect patients at high risk of upper urinary tract complications and demand immediate introduction of bladder catheterization (if not already implemented) [6]. The PVR volume at which the patient’s bladder-emptying technique should be changed is related to the overall bladder capacity and remains a matter of dispute [27]. Nowadays, it is recommended to introduce patients to catheterization techniques when a PVR volume consistently exceeds 100 mL and patients present with related symptoms [10, 28]. Implementation of PVR measurement during the initial evaluation of SCI patients may also help in future evaluation of potential changes in bladder behavior. Currently available data suggest that ultrasound measurement of PVR is preferable to catheterization; portable scanners can be easily used in daily clinical practice [29–33].

As patients after SCI are at high risk for upper urinary tract deterioration by secondary reflux, hydronephrosis , ascending infection, and stones , baseline kidney evaluation with ultrasound should be performed during the first appointment [6, 34–36]. It is important to rule out any concomitant disorders or already developed complications at the start of management. Clinicians should also perform ultrasound as a benchmark for potential changes that may be found during future follow-up. Furthermore, ultrasound is considered a very safe procedure with minimal known adverse effects and no radiation exposure. Ultrasound gives information about renal size as well as position, cortical thickness, collecting system dilation, abnormal masses, scarring, stones , and other structural changes affecting the parenchyma (Fig. 5.2) [37]. Healthy adult kidneys commonly measure between 9 and 12 cm in length and have a cortical thickness measurement >1.5 cm [38]. Abnormal findings may indicate a wide variety of renal parenchymal disorders that can affect renal function, including end-stage renal disease (Fig. 5.3) [39, 40]. No consensus exists regarding a standardized definition of hydronephrosis . In daily clinical practice, when hydronephrosis presents, it is usually classified as mild, moderate, or severe (Fig. 5.4) [41]. As intra-observer variations in ultrasound assessment are well known, obtained results can significantly vary among clinicians. Nevertheless, severe hydronephrosis has characteristic ultrasound image, consisting of collecting system dilatation extended into renal parenchyma with cortical loss in long-standing cases [42]. Utilization of Doppler function with measurement of blood flow and resistance in the intrarenal arterial waveforms can also be used to assess the impact of hydronephrosis on renal function [42]. Besides, Doppler ultrasonography can help in differentiation between acute and chronic hydronephrosis [43, 44]. Color flow Doppler ultrasound may also support and eventually replace retrograde cystography in the detection of vesicoureteral reflux. It has been shown that color Doppler ultrasonography can diagnose all grade IV and V refluxes, almost 90% of grade III, more than 80% of grade II, and almost 60% of grade I [45].

Bladder ultrasound helps to detect bladder stones , which are reported in almost 30% of patients with indwelling catheters (Fig. 5.5) [46, 47]. Of note, the National Institute for Health and Care Excellence (NICE) recommends referral for cystoscopy in patients with NB and suspected bladder stones on the basis that cystoscopy is the most reliable investigation for detecting bladder calculi (which can be small and poorly calcified in some cases) [6]. Bladder ultrasound may also support in the detection of bladder tumors (Fig. 5.6) [47]. It has been hypothesized that frequent detrusor contractions may increase detrusor/bladder wall thickness (DWT/BWT) . Therefore, DWT/BWT and ultrasound-estimated bladder weight are being investigated as non-invasive tests in the assessment of patients suffering from NB (Fig. 5.7). However, recently published data suggest that routine clinical assessment of BWT for monitoring the effects of treatment of detrusor overactivity is not clinically useful [48, 49] and standardization of the technique has not been demonstrated [50]. In view of these findings, DWT/BWT should not be included in the initial assessment or as a follow-up screening tool for SCI patients.

Urethrocystoscopy may be part of the initial evaluation of SCI individuals with NB. It is required in patients with unexplained or alarm symptoms, such as hematuria, chronic or recurrent UTI, and recurrent catheter blockages, usually indicating complications of NB. These include urethral strictures, trabeculations, bladder stones , bladder cancer , and diverticula. Indwelling catheters, intermittent catheterizations, and multiple endoscopic procedures may lead to urethral strictures and false passages with difficult catheterization. Bladder wall trabeculations may indicate high bladder pressure related to overactivity or infravesical obstruction [51]. As patients with NB are at higher risk of UTI, bladder stones can also be found, particularly in patients who present with recurrent UTI, bladder pain, or microscopic hematuria. Bladder cancer in patients after SCI was the subject of several studies that concluded that SCI may increase the risk of bladder neoplasm [52, 53]. The exact pathomechanism of this phenomenon is still unknown and includes not only the utilization of chronic indwelling catheterization. Moreover, proper evaluation of bladder mucosa in chronically catheterized patients may be challenging. Local irritative effect of the catheter and the balloon, usually within bladder trigone, can be difficult to distinguish from an early carcinoma. Therefore, urethrocystoscopy should sometimes be combined with bladder washing cytology or biopsy. Iatrogenic (e.g., sutures, pieces of Foley catheter) and non-iatrogenic (e.g., hairs) foreign bodies are rare findings in NB patients. In patients with a suprapubic tube, endoscopic bladder examination can be performed per the urethra or through the suprapubic tract [51].

It should be noted that urethrocystoscopy should not be used for functional evaluation of the lower urinary tract. Voluntary contractions of the external urethral sphincter or status of the bladder neck (degree of opening), both assessed during endoscopic examination, cannot replace functional studies [51]. Well-conducted urethrocystoscopy should also assess ureteral orifices. As a result of high bladder pressure and changes in bladder wall thickness, they can become widely open. Similarly, vesicoureteral reflux cannot be diagnosed based on endoscopic examination but requires a voiding cystourethrogram.

Advanced imaging techniques should not be included in the initial evaluation of patients with NB. Computed tomography or magnetic resonance imaging may be required in those reporting worrisome symptoms such as hematuria, suprapubic pain, or recurrent UTI [54]. The use of these advanced diagnostic tests as well as other imaging techniques (e.g., X-ray of the urinary tract, intravenous urography, cystogram/voiding cystogram, nuclear scans) should be based on patient history and physical examination, and definitely considered in patients after bladder reconstructions [55]. The imaging techniques for investigating the upper and lower urinary tracts can be documented with the International Urinary Tract Imaging Basic SCI Data Set (Fig. 5.8) [56, 57].

Non-invasive uroflowmetry can be used as a screening test for voiding dysfunction. This technique involves measuring the speed, volume, and duration of release of urine and provides with objective information. Possible pathological findings include a low flow rate, intermittent flow, hesitancy, and low voided volume. It may help to select patients who require more sophisticated urodynamic studies. However, uroflowmetry is non-specific and may indicate bladder outlet obstruction, detrusor-sphincter dyssynergia, or bladder underactivity. Uroflowmetry does not allow for evaluation of bladder compliance, a critical component in the assessment of SCI patients [58]. Furthermore, the test requires voluntary control of voiding, making utilization of this test limited or even unfeasible in patients after SCI [10]. Finally, the results obtained describing flow pattern and rate may be modified by inappropriate positions during voiding, a significant issue in SCI patients .

Urodynamic study is the cornerstone of evaluation in patients with neurogenic lower urinary tract dysfunction. It provides objective data of the effect of neurological lesion on lower urinary tract function during bladder filling and eventual controlled voiding. As patient’s symptoms and signs and level of SCI do not always correlate with bladder dysfunction, urodynamic study helps to investigate the underlying dysfunction and consequently allows for the initiation of proper treatment [59]. Urodynamic results can significantly help to assess the patient’s prognosis and the risk of deterioration to the upper urinary tract, resulting in adequate follow-up monitoring. It is generally agreed that urodynamic study should be conducted to provide a precise diagnosis for each patient [60]. Multiple studies have demonstrated the clinical value of urodynamics, independent of factors relating to the spinal cord lesion [58, 61].

The urodynamic evaluation consists of several components. To properly perform this complex diagnostic procedure, it should be conducted with validated methods, recommendations, and standards. Technical points on how to undertake urodynamic testing and how to report findings have been set out and recently updated by the International Continence Society in their “Good urodynamic practices” document [62]. This data synthesis should be employed in the daily practice of clinicians who treat neurourological patients.

In individuals suffering from neurogenic lower urinary tract dysfunction, particularly after SCI , special consideration needs to be given to filling cystometry , pressure-flow study, and electromyography .

The technique of the filling cystometry , described as continuous fluid filling of the bladder via a transurethral catheter or other route (e.g., suprapubic, mitrofanoff), is used to mimic the bladder’s filling and storage as well as to record the pressure–volume relationship within the bladder. Therefore, cystometry allows for the evaluation of intravesical pressure, bladder wall compliance (ability of the bladder to accommodate the increasing volume with low pressure), bladder sensation, and involuntary detrusor contractions. The results obtained may include detrusor overactivity, low bladder compliance (leading to high bladder storage pressure), abnormal bladder sensation, incontinence, and incompetent or relaxing urethra [63]. Some technical aspects should also be considered. The bladder should be empty at the start of filling. As fast filling and room-temperature saline may provoke bladder instability, a physiological filling rate should be used with body-warm saline [63]. Bladder compliance also seems more reproducible using slower fill rates [14, 58]. Currently, it is advised to start filling at a low rate of 10 mL/min or less [25]. Then, the bladder filling can be maintained at a rate of 20–30 mL/min if no increase in detrusor pressure has been seen [58, 63]. Filling rates greater than 20% of estimated bladder capacity have been shown to artificially raise detrusor pressures [64]. If the detrusor pressure continues to increase with filling, decreasing the filling rate or stopping the infusion may be required [25]. This method can help to evaluate whether increased pressure has been induced by detrusor contraction or impaired compliance. Evaluation of the detrusor leak point pressure should be analyzed with caution due to low sensitivity in the estimation of the risk for upper urinary tract deterioration or secondary bladder damage [63]. Detrusor leak point pressure of 40 cm H₂O is considered as a cut-off value for upper urinary tract failure [65]. Similarly, urethral pressure profiles are seldom used in patients with SCI [10].