J Anat. Soc. India 49(2) 161-164 (2000)
Efficacy of Manual Bladder Expression in Relieving Urine Retention After Traumatic Paraplegia In Experimental Animals.
Preeths, T.S., Sankar, V. Muthusamy, R. Department of Anatomy, Dr. A. Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai 600 113, India.
Abstract : Urine retention is one of the serious complications of traumatic paraplegia. It leads to infection with subsequent renal failure. Various strategies like indwelling or intermittent catheterization, supra pubic cystostomy, electrical stimulation of bladder and manual expression of bladder (MEB) may be adopted to relieve the urine retention. Intermittent catheterization evolved as the method of choice over MEB in human paraplegics. Such therapeutic dilemma does not seem to prevail in relieving urine retention in experimental paraplegic animals as invariably in all studies, MEB was practised. However, there is no experimental study dealing with the efficacy of this method in animals. In the present work, using paraplegic bonnet monkeys as non-human primate model, the efficacy of MEB was assessed through microbiological, biochemical and histological parameters. A comparison was also made between MEB and intermittent catheterization. The observations indicate that MEB was highly effective and except for the mild occurrence of urinary tract infection, there was no major complications contraindicating its usage. In the long term both MEB and intermittent catheterization should give identical results in experimental animals. As MEB is relatively a simple, quick, economical and complication free procedure when compared with intermittent catheterization, its usage in experimental animals may be justified. Owing to the advantages listed above, it is tempting to postulate that MEB may be practised as a routine procedure to relieve urine retention in human paraplegics also.
Keywords : Urine retention - Manual Bladder Expression-Traumatic Paraplegia-Bonnet monkey
Introduction :
Urine retention due to paralysed bladder after any spinal cord injury is a serious problem since it can lead to irreversible damage to the urinary system (Bannister, 1984). Over several decades, various strategies were adopted to relieve urine retention in a spinal cord injury victim. These include indwelling catheter (Nanninga, et al., 1982), supra pubic cystostomy (MacDiarmid, et al., 1995), bladder stimulation (Madersbacher, et al., 1982), Sacral root stimulation (Creasey, 1993), and intermittent catheterization (Nanninga, et al., 1982). Surgical interventions such as bladder neck resection and/or external sphincterotomy (Al-Ali and Haddad, 1996) and sacral posterior rhizotomy (Schurch, et al., 1997) were also carried out based on various rationals. Manual expression of bladder (MEB) is a method in which either patients themselves or by a assistant, strain the abdomen so that voiding occurs due to compression of the urinary bladder (Smith, et al., 1972). This method was practised in 1970s after which the interest swung towards intermittent catheterization as more and more reports came in favour of it (Hill and Davies, 1988).
In the bladder management of spinal cord injury experimental animal models, many of the above mentioned techniques were not used. Manual expression of bladder (MEB) was the single method used since the early part of this century (Sugar and Gerard, 1940). In a few works involving paraplegic animals, simple urine analysis using urine sediment microscopy and urine culture studies had been undertaken (Rivlin and Tator, 1977). Except these early works conducted in rats, the efficacy of MEB was never assessed. Review of literature revealed that there is no comprehensive work about the efficacy of MEB especially in the long term postoperative survival of paraplegic monkeys. In this context, the present work was aimed to study the effectiveness of MEB in paraplegic monkeys. Its usefulness in the case of human paraplegics has been discussed.
Materials and Methods :
Twelve paraplegic female bonnet monkeys ranging in body weight from 0.5 to 1.75 kilograms were used. These monkeys were group of animals used in the project on neural transplantation after traumatic paraplegia. Paraplegia was produced by microsurgical transection of the spinal cord at T11 - T 12 spinal segment junction under thiopentane anaesthesia (30mg/Kg of body weight). Animals were divided into the following two groups.
Group I | - Urine retention relieved by manual expression of bladder 4 times daily (n = 10) |
Group II | - Urine retention relieved by intermittent catheterization 4 times daily. (n = 2) |
At random, in a few group I animals, catheterization was performed after MEB, to assess the residual urine. Every week, microbial culture of supra pubically aspirated urine samples were carried out to detect any urinary tract infection. In the case of growth in culture plates, antibiotic sensitivity was studied. Suitable antibiotic therapies were instituted. Fortnightly, serum urea and creatinine analyses were done to assess renal function. Due to various complications, animals were sacrificed at different postoperative periods ranging from 10 days to 2 years. The animals of Group II were sacrificed after 60 days of postoperative survival.
Animals were fixed by vascular perfusion using formal saline. The kidney was dissected out and post fixed in the same fixative. The tissues were processed for standard Paraffin Technique, sections were cut at five micron thickness and were stained with
Haematoxylin and Eosin | - for general histological evaluation |
Gram Stain | - for the presence of gram-positive bacteria |
Twort Stain | - to stain gram negative bacteria |
Congo red | - for the demonstration of amyloid if present. |
Observations :
In the MEB group of animals, incidence of urinary tract infection was quite high during the first month of postoperative survival beyond which, there was no incidence of urinary tract infection. Except for this, there was no significant difference between the two groups. In three animals of group I and one animal of group II, kidneys showed mild collecting tubular damage (Fig. 1). However, in the other animals including long-term animals of MEB group tubules appeared normal (Fig. 2). Comparison between the two groups of animals is given in Table 1.
Most of the animals were sacrificed due to septic complications, which resulted from the infection of pressure sores. Some of the animals with septic complications showed overall body edema and there was a sudden increase in the serum urea and creatinine levels (serum urea 41 mgs %, normal value being 11 mgs % and serum creatinine 0.6 mgs%; normal value being 0.5 mgs %). Severe anaemia [1.9 million RBC/cu. mm and 4.9 gm% haemoglobin against the normal value of 13.5gm%] was seen in such animals. Histological sections of the kidney from such animals showed bacterial seeding in the cortex (Fig. 3). No amyloid depositions were seen in the kidneys.
Discussion :
Except for increased incidence of urinary tract infection in the first month, MEB offers results equal to that of intermittent catheterization. More residual urine volume after MEB could be the cause of this as stagnant urine would promote bacterial growth. Once automatic bladder was established, urinary
Table 1. Comparison between manual expression of bladder and intermittent catheterization.
Parameter | Group I Manual Expression of Bladder (n = 10) | Group II Intermittent Catheterization (n = 2) |
Residual urine after the procedure (i.e. after bladder expression or catheterization) | 1 to 2 ml (Total Bladder capacity is 10-15 ml) | Nil |
Automatic bladder Establishment | 8-15 days (average 10 days) | |
Residual urine after the automatic bladder | Less than 1 ml | Less than 1 ml. |
Presence of urinary tract infection | Not present beyond one month of post operative period | Not present beyond one month of post operative period |
Incidence of urinary tract infection in first month of post-operative period | >80% (12 out of 15 cultures were positive | 16.66% (1 out of 6 cultures was positive) |
Commonly isolated bacteria during urinary tract infections | E. Coli, Klebsiella | E. Coli, Klebsiella |
Evidence of renal failure in long term (>30 days) assessed using biochemical parameter - serum urea and creatinine | Nil | Nil |
Histological changes in kidney (at comparable post-operative survival i.e. <60 days) | Present-Mild collecting tubular damage seen in three animals | Present - Mild tubular damage seen in one animal |
Histological appearance in long term (i.e. > 60 days) | No evidence of damage | Not applicable (As POP is 60 days only) |

Fig.1. Photomicrograph showing damage of renal collecting tubules in some of the paraplegic bonnet monkeys during short-term postoperative survival. Hyaline degeneration is evident from eosionophilic nature and loss of details in the tubulus. DT-a degenerated tubule. Arrow shows a breakage in the walls of a tubule which is in the process of degeneration. Arrow head points to a infiltrated cell. Haematoxylin and Eosin staining. Transverse Section. Magnification 200 X.

Fig. 2. Renal collecting tubules of a long term-survived paraplegic bonnet monkey. Tubules appear normal with distinct lumen
and lining cells. Can be compared with Fig. 1. Haematoxylin and Eosin staining. Transverse
Section. Magnification 200 X.

Fig. 3. Heavy seeding of the renal cortex with bacteria and infiltrated cells in a paraplegic bonnet monkey
with septicemia. Glomeruli (G) were normal ruling out any glomerulo nephropathy. Arrow points to distal convoluted tubule and arrow head indicates a proximal tubule. Unlike collecting tubules shown about, proximal and distal tubules did not show any degenerating signs as evident from this illustration. Haematoxylin and Eosin staining. Transverse Section. Magnification 40 X.
tract infection became rare in these animals. In this context, MEB excel intermittent catheterization in establishing automatic bladder in a shorter time (however due to the lack of enough sample size, statistical significance could not be drawn to support this statement). It has been established that ; earlier the bladder stimulation after spinal cord injury, better will be the outcome (Hassouna, et al., 1992). MEB may serve as a non-invasive bladder stimulation as during which, increased bladder pressure may reach spinal cord through afferent routes thus serving as a stimulation source. Such early conditioning of spinal circuits with afferent stimulation might help in the better re-organisation of the same leading to early establishment of automatic bladder. In short term, there was slight renal tubular atrophy evident in both groups. As tubular atrophy was present irrespective of the method employed to resolve urine retention, the effectiveness of MEB and intermittent catheterization can not be assessed based on this. Thus in the long term, both the methods should offer almost identical results.
At the terminal stage of animals with septicaemia, there was evidence of the impairment of renal function. However, this sort of renal failure could be due to the complications of septicaemia rather than any thing in connection with urine retention and its management. The supporting points for this view are listed below.
1. Urine culture before the terminal episode was sterile, indicating the infection free state of lower portions of urinary tract.
2. Bacterial seeding was seen in the cortex, suggesting a haematogenous route. Such seeding in the cortex prevented there shedding in the secreted urine; thus giving negative urine cultures (Ritchie, 1961).
3. Bacteria seen in the kidney tissue planes were identified to be Group D streptococci (Smith and Easman, 1990), which are the commensal of large intestine. Blood cultures taken before sacrifice of the animals grew the same kind of organisms.
Thus, the bacteria might have gained entry into blood from the faecal matter soiled pressure sores.
Thus in our experimental animals, although initially there were urinary tract infection and mild renal tubular damage, in long term, MEB was found to offer good results and its efficacy was clearly established.
Some method to relieve urine retention has to be practised continuously in human paraplegics as even after automatic bladder development there will be some residual urine and more importantly automatic bladder may some times fail to develop (Lynn, 1970). Intermittent catheterization has evolved as the method of choice in human paraplegics (Maynard and Diokno, 1982; Maynard and Glass, 1987; Bennett et al., 1995). However, studies on intermittent catheterization revealed several blemishes, which question its superiority. These include; need for constant monitoring, periodical hospitalisation, urinary tract infections and other complications, patient's unacceptability, need of a understanding patient with good hand skill for self catheterization or need of a good assistance etc. (Maynard and Diokno, 1982; Maynard and Glass, 1987; Yadav, et al., 1993; Bennett, et al., 1995). On the other hand some of the practices like supra pubic cystostomy and indwelling catheterization which were condemned long before were now found to offer good results in selected cases (MacDiarmid, et al, 1995). In this context, MEB is less commonly advocated as a single method. This is mainly because MEB results in small quantities of residual urine after its performance. However, in our opinion, MEB may be advocated, as it only requires periodical assessment of renal function against any possible damage due to infections. It may be recalled here such constant monitoring was required even for the so-called method of choice `clean intermittent self catheterization' during long term management.
The advantages of adopting manual bladder expression in experimental animals were given by comparing this with intermittent catheterization through Table 2.
Table 2. Advantages of Adopting manual expression of bladder over intermittent catheteresation
Manual Expression of Bladder | Intermittent Catheterization |
Does not involve any expensive materials | Involves expensive sterile disposable items to perform it in an aseptic manner. |
Experimenter alone can perform this | Requires manpower to retain the animal in convenient position and to assist. |
Quick procedure and no physical embarrassment to the animal. | May be prolonged as it is difficult to catheterise urethra due to its small size and animals may have to be restrained for a longer time. |
No secondary complication | Secondary complications such as urethral stricture due to the injury caused by repeated catheterization and allergic reactions to the catheter material or lubricant used may arise. |
Automatic bladder is quickly established* | Automatic bladder establishment may be delayed* |
* Needs statistical confirmation | |
Our study clearly justifies the effectiveness of MEB at least in paraplegic animals, leave alone our assumptions about its usefulness in human paraplegics. From our observations, there are no contra-indications for the practise of MEB in paraplegic animals. The success achieved in animals may however be due to the following two possibilities.
1. In monkeys, the anterior abdominal wall is very thin and a satisfactory palpation of the bladder is possible. Thick, muscular anterior abdominal wall of human may not allow effective expression of bladder.
2. Voiding control in monkeys may be at a spinal level and the supra-spinal influence may be negligible, as voiding is not related to socio-environmental conditions. Therefore, pressure created manually may stimulate spinal centres through afferent connections, thus mimicking condition as in the case of natural voiding. In human, the spinal centres that control voiding are also under the control of cerebral cortex. The role of supra spinal centres in such voluntary control must be taken into account. In human paraplegics, though manual expression can stimulate spinal centres as in the case of monkeys, they may not empty the bladder very effectively since the dependence of spinal cord on cerebral cortex increases with the increase in the phylogenetic level of the organism.
Conclusion :
Efficacy of manual bladder expression in relieving urine retention after traumatic paraplegia in bonnet monkeys was studied. The results were analysed using microbiological, biochemical and histological methods and were compared with results obtained from animals in which urine retention was relieved through intermittent catheterization. From the observations, manual bladder expression was found to offer results equal to that of intermittent catheterization and therefore its usage in experimental animals may be fully justified. Its effectiveness as a single method to relieve urine retention in human paraplegics is worth a study.
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