Renal blood flow and pelvic pressure after 4 weeks of total upper urinary tract obstruction in the pig

Summary In 8 female pigs complete unilateral ureteral obstruction was investigated over a 4 weeks period. The pigs were monitored with intrapelvic pressure measurements and by 131-I-hippuran scintigraphy twice a week; one group without and one with TxA₂ blocking, UK-38,485 [3-(1H-imidazol-1-yl-methyl)-2methyl-1H-indol-1-propanoic acid], which is a well-known selective thromboxane synthetase inhibitor. During the course of obstruction there was an ipsilateral linear reduction of split function to background level and a net reduction in total hippuran clearance in both groups. On the obstructed side there was a linear reduction of hippuran clearance from 116±26 ml/min to 11±3 ml/min during the first 2 weeks of obstruction. The TxA₂ synthetase inhibitor, 5 mg/kg reduced se-TxB₂ to almost zero for at least one hour after i.v. administration. One week after obstruction the pelvic pressure was 45±5 cm H₂O administration of the TxA₂ synthetase inhibitor. The pelvic pressure remained elevated throughout the period of observation. The study confirmed earlier work which showed that total ureteral obstruction caused complete cessation of kidney function within a few weeks, but contradicts previous studies because there was no increase in renal blood flow after thromboxane blockade. These differences may be explained by several mechanisms. The continuing increase in pelvic pressure suggested that it was not only a preglomerular vasoconstriction which was responsible for the renal flow reduction, but that there was also a postglomerular vasoconstriction.     

Obstruction of the upper and lower urinary tract

Obstruction of the urinary tract in the adult can occur at any point from the calyces to the external urethral meatus. Obstruction within the urinary tract is best divided into upper tract and lower tract obstruction and obstruction can be acute or chronic. Acute upper tract obstruction is most commonly due to a calculus and acute lower tract obstruction in men is often due to benign prostatic enlargement. Chronic upper tract obstruction in the Western world is most commonly due to calculi or pelvi-ureteric junction obstruction. Chronic lower tract obstruction in men will again be due to benign prostatic enlargement in a majority of cases.     

Obstruction of the upper and lower urinary tract

Obstruction of the urinary tract can occur at any point from the calyces to the external urethral meatus. Obstruction within the urinary tract is best divided into upper tract and lower tract obstruction. Obstruction can be acute or chronic. Acute upper tract obstruction is most commonly due to a calculus and acute lower tract obstruction in men is often due to benign prostatic enlargement. Chronic upper tract obstruction in the Western world is most commonly due to calculi or pelvi-ureteric junction obstruction. Chronic lower tract obstruction in men will again be due to benign prostatic enlargement in a majority of cases.     

The relationship of urethral resistance pressure and pressure flow parameters in women with lower urinary tract symptoms

This prospective study aims to evaluate the relationship between urethral resistance pressure (URP) and pressure flow parameters in women with lower urinary tract symptoms (LUTS). Consecutive women with LUTS attending three tertiary referral urodynamic clinics were asked to undergo urodynamic evaluation, pressure flow studies and URP measurement. The pressure flow parameters such as detrusor pressures at the start of flow (ODP), detrusor pressure at peak flow rate (PdetQmax), peak flow rate (Qmax) and detrusor pressure at the end of flow (CDP) were measured. The relationship between URP and pressure flow parameters was evaluated as well as differences between each urodynamic group. Two hundred seventy-nine women attended for urodynamic investigations. Two hundred twenty-three (79.9%) women had good quality pressure flow measurements and were included in the study. The mean age was 58 years (range 21–83). Women with urodynamic stress incontinence had significantly lower URP and ODP than those with detrusor over-activity [54.8 (±17.9) and 12.4 (±4.1) cmH₂O, respectively, vs 85.6 (±21.4) and 33.7 (±13.3) cmH₂O, respectively) (p<0.05, Bonferroni test). Furthermore, women with urodynamic stress incontinence have significantly lower PdetQmax values as well as higher Qmax than women with competent urethral sphincters (p<0.05, Bonferroni test). There was a significant correlation between ODP, PdetQmax, Qmax and URP measurements. In urodynamic stress incontinence, both URP and pressure flow parameters are reduced. Although the trend for values of both tests were similar and there was a significant correlation between these tests, we should consider that urethral function at rest differ from that during voiding due to activation of additional mechanisms. Therefore, further study is needed to confirm our results.     

Pressure flow study: a useful diagnostic test of female lower urinary tract symptoms

AIMS: To compare pressure flow parameters in the different urodynamic diagnoses in women with lower urinary tract symptoms (LUTS). MATERIALS AND METHODS: Urodynamic traces of women with LUTS were prospectively studied. Detrusor pressures at the start of flow (ODP), detrusor pressure at peak flow rate (PdetQmax), peak flow rate (Qmax) and detrusor pressure at the end of flow (CDP) were measured and compared with different urodynamic diagnoses. RESULTS: Six hundred and twenty one women were prospectively investigated between September 2000 and February 2002. Only 85% (529/621) of women had good quality pressure flow studies and was included in the study. Women with detrusor overactivity have higher ODP, CDP and PdetQmax than women with urethral sphincter incompetence. All these pressure flow parameters are significantly lower in women with urethral sphincter incompetence than continent women (P < 0.05, Bonferroni test). Qmax was significantly greater in women with urodynamic stress incontinence compared to women who had detrusor overactivity (P < 0.05, Bonferroni test). Women with mixed incontinence had pressure flow parameters intermediate between women with detrusor overactivity and those with urodynamic stress incontinence. CONCLUSIONS: Pressure flow parameters appear to be useful urodynamic tools in the evaluation of women with LUTS as they help the clinician in assessing the urethral and detrusor function.     

肾动态显像定位诊断上尿路梗阻

静脉注射９９ｍＴｃＥＣ后立即动态采集双侧肾脏、输尿管及膀胱影像２０分钟，获得上尿路显像图、肾图曲线、输尿管曲线及高峰时间、高峰幅度、半排时间和２０分钟排泄率等定量参数。３００例受检病人中正常９３例，单纯显像异常９例，动态显像及肾功能、肾血流均异常１９８例，其中肾性梗阻１４２例，输尿管上段梗阻１９例、中段１６例、下段２１例。４０例病人同时作肾图，２０例作血清尿素氮和肌酐检查，４０例做Ｂ超、ＫＵＢ、ＩＶＵ检查，符合率分别为７３％、７５％和９０％。１０例经手术对照均符合诊断。结果表明：肾动态显像对于上尿路梗阻定位诊断、肾功能及肾血流判断具有较高价值，可常规用于临床。     

磁共振尿路造影在上尿路梗阻诊断中的应用

目的　评估磁共振尿路造影技术在诊断上尿路梗阻性疾患中的价值。　方法　采用磁共振尿路造影术（ Ｍ Ｒ Ｕ） 诊断上尿路梗阻患者３５ 例。　结果　所有病例均清晰显示梗阻部位及尿路积水情况。　结论　 Ｍ Ｒ Ｕ 是一种无创性、无需造影剂的诊断上尿路梗阻的方法。     

A novel quantitative method for measuring obstruction in the upper urinary tract: The 'obstruction coefficient'

Objectives:   To define an exact pressure-flow correlation in the upper urinary tract using an improved measurement method, to quantitatively characterize the degree of postrenal obstruction and to find a simple way of calculating it in everyday urological practice.
Methods:   The data of 112 cases were included in the analysis. The dynamic method of a multistep, constant pressure perfusion study was used to precisely measure a wide range of pressure-flow dependences. Values of established parameters measuring the degree of obstruction were compared: the intrapelvic pressure, the ureteral opening pressure and the newly introduced 'obstruction coefficient'.
Results:   Pressure-flow relations can be best presented by a parabolic curve described by the simple formula Y = AX² + B. Depending on the degree of obstruction, the shape of this curve can be characterized by a single number, that we defined as the 'obstruction coefficient'. Computer-based evaluation software for the easy calculation of this coefficient is presented here and freely available on demand. The Whitaker-test, the ureteral opening pressure, and the 'obstruction coefficient' showed significant correlation proving that the latter was clinically applicable in measuring the degree of obstruction.
Conclusion:   Calculation of the 'obstruction coefficient' enables us to exactly define the degree of upper urinary tract obstruction and to safely monitor for a long period conditions inhibiting ureteric passage.     

恒压肾盂灌注试验在判断上尿路手术疗效中的作用

用恒压肾盂灌注（ＣＰＰ）试验检测了１０例解除上尿路梗阻术后病上尿路功能，并将其结果与夹管试验和造影检查比较，以评价手术疗效。ＣＰＰ试验结果通畅者术后随记肾功能均改善，不通畅者则肾功能恶化。夹管试验阴性者在部分肾功能改善，小部分肾功能恶化。造影检查通畅者肾功能均改善，但有部分梗阻得，其预后难以估计。我们认为ＣＰＰ试验判断上尿路梗阻解除手术疗效准确可靠。     

经皮肾穿刺造瘘在上尿路梗阻性疾病的应用

目的:探讨经皮肾穿刺造瘘在上尿路梗阻性疾病(UUTO)的应用价值.方法:对42例UUTO患者,先行经皮肾穿刺造瘘引流,待肾功能改善、机体状况好转或经引流及造影确定诊断之后,12例行经皮肾取石碎石术,11例行开放肾、输尿管切开取石术,4例行开放肾切除术,4例行肾盂输尿管成型(3例加行取石)术,3例经造瘘管注射硬化剂治疗,3例行输尿管肾盏吻合术,3例行输尿管狭窄段切除端端吻合术,1例行输尿管松解术,1例行输尿管皮肤造瘘术.结果:38例患者一次穿刺成功.全部病例均及时解除了上尿路梗阻,肾功能得到改善,或为进一步诊治创造了条件.在保肾治疗的35例,31例治愈出院;4例肾功能改善,维持在轻度氮质血症水平;4例肾切除患者和3例注射硬化剂治疗患者均治愈出院.结论:经皮肾穿刺造瘘安全、有效,在UUTO的诊治中具有重要的应用价值.     

急性上尿路结石梗阻的影像学分析

目的：探讨超声、腹部平片（ＫＵＢ）、静脉尿路造影（ＩＶＵ）对急性输尿管结石梗阻的诊断价值。方法：回顾性分析３５２例急性输尿管结石梗阻患者的Ｂ超、利尿性Ｂ超、ＫＵＢ、ＩＶＵ的诊断结果。结果：对肾积水的诊断,常规Ｂ超诊断率８３．２％（２９３／３５２）,而５９例可疑病例利尿性Ｂ超的诊断率７９．７％（４７／５９）,利用常规Ｂ超加利尿Ｂ超检查,对梗阻性肾积水的诊断率９６．６％（３４０／３５２）;对输尿管结石     

Consequences to the upper urinary tract after ureteric torsion

Summary The effects of ureteric torsion on the upper urinary tract were studied in 8 pigs. With 5 pigs the distal ureter was mobilised, torted 1 to 5 times and reimplanted into the bladder. With three pigs the proximal ureter was torted 1 to 3 times and re-anastomosed to the renal pelvis. It was shown that a torsion of 1 or 2 times in the distal ureter does not result in ureteral obstruction. However, as little as 360 degrees torsion in the proximal ureter may lead to dysfunction secondary to mechanical obstruction. Histological examination of the ureter showed ischaemic changes only after multiple torsions.     

MRU诊断上尿路梗阻性疾病的价值

目的 探讨磁共振尿路造影（MRU）诊断上尿路梗阻性疾病的意义。方法 59例上尿路梗阻性疾病患者接受检查，MRU为冠状位快速自旋回波T2加权像。结果 所有病例MRU尿路梗阻部位及扩张状况均显示良好，其中54例经手术或病理确诊，仅2例术前MRU误诊。结论 MRU作为一种非侵袭性、无辐射损伤和不需造影剂的新技术，对上尿路梗阻性疾病的定位及定性诊断具有特殊价值，是一种可供选择的有临床实用价值的尿路成像方法。     

The length and collapsibility of the ureter play roles in the augmented reflection of intraabdominal pressure into the renal pelvis

Background/purpose

Flow of a fluid through a collapsible tube is under the influence of various factors including the external compressing pressure. The intraabdominal pressure (IAP) should influence the flow through the ureter. Therefore, an experimental study was planned to investigate the effects of ureteral length and external compressing pressure onto the intrapelvic pressure (IPP) in rabbits.

Methods

Nineteen adult rabbits were used for the experiment. Under general anesthesia, an intraperitoneal and an intrapelvic catheter were placed to measure IAP and IPP. A urethral catheter was placed for bladder decompression. After this standard preparation, a ureteric stent was placed in the ureter in group 1 (n = 7). Distal or proximal ureter transection was performed in group 2 (n = 6) and group 3 (n = 6), respectively. Basal pressure measurements have been recorded. Then the pressures were recorded every 5 minutes, and IAP was increased gradually for 4 cm of water pressure in each subsequent 30-minute period. All analyses were performed for a standard IAP interval (5 to 25 cm H₂O).

Results

IAP did not differ between groups (P = .08). IPP values were significantly higher than the corresponding IAP values in each group (P = .0001). IPP showed significant difference between IAP values of groups (P = .0001). IPP was significantly increased in group 2 when compared with group 1 and group 3 (P = .0001; P = .0001), but no difference was encountered between groups 1 and 3 (P = .1). There has been a strong relationship between IPP and IAP values in all groups. The Rsq values were 0.912, 0.783, and 0.943 for group 1, group 2, and group 3, respectively (P < .0001). Mathematic relations between IPP and IAP also were analyzed. The relations were IPP = 3.9 + 1.10 × IAP, IPP = 10.3 + 1.10 × IAP, and IPP = 3.3 + 1.12 × IAP for groups 1, 2, and 3, respectively.

Conclusions

Renal pelvis pressure responds with augmented increases to increments in IAP in urinary tracts with different ureteric lengths. Increase in IPP is more pronounced in longer ureters possibly owing to increased resistance to flow. Prevention of ureteric wall collapse reverses the augmented increase in IPP responses. Therefore, both the length and collapsibility of the ureter play a detrimental role in the generation of augmented IPP responses to increments in IAP. The magnitude of IPP as a response to increments in IAP can be estimated by using mathematical relations between IPP and IAP. Increases in IAP may simulate proximal ureteric obstruction and may take part in the pathogenesis of hydronephrosis.     

磁共振水成像对上尿路梗阻的诊断价值

目的:评价磁共振水成像(MRU)对泌尿系梗阻性疾病的临床诊断价值。方法:采用快速自旋回波重T2加权序列和脂肪抑制技术,对56例经B超和IVP怀疑上尿路梗阻患者,进行泌尿系冠状位扫描,将图像按最大强度投影法重建出MRU图像。结果:其中32例MRU均能清晰显示尿路梗阻的部位和肾盂积水,解剖结构清楚,可对梗阻作出定性诊断,并经手术和病理证实为尿路梗阻者。其中尿路结石16例,尿路先天性梗阻4例,输尿管炎性狭窄2例,移植肾输尿管狭窄2例,其他8例。余26例排除上尿路梗阻。结论:MRU是无创伤的检查方法,不接触射线,不需碘对比剂,诊断尿路梗阻性疾病定位、定性准确,尤其适用于因严重梗阻IVP显影不良的病例。     

A comparison of spontaneous and intubated urinary flow in female patients

In 60 female patients with lower urinary tract disorders the natural urinary flow was compared with the flow obtained with two 5 F urethral catheters in place. For the group as a whole there was no significant decrease in the intubated maximum flow rate whereas the intubated average flow decreased significantly. Among patients with a spontaneous flow rate of < 15 ml/sec no effect of the catheters was observed; actually the maximum flow rate increased significantly, which, however, may be due to increased voided volume. The transurethral technique for pressure-flow studies offers a simple method for the assessment of detrusor contractility and for the identification of patients with infravesical obstruction. It can be performed without further invasion in conjunction with routine cystometry studies. Therefore this technique is recommended in the routine urodynamic workup in females with lower urinary tract disorders.     

An evaluation of 170 diagnostic pressure flow studies of the upper urinary tract.

An analysis of 170 pressure flow perfusion studies reveals that they can be valuable in patients of all ages, but particularly so in children, and in a variety of clinical conditions. The complication rate is low and there are few patients in whom these studies do not provide a clear-cut answer on the degree of obstruction. They can be recommended as useful and, at times, invaluable clinical tools.     

上尿路梗阻性无尿的原因及处理

目的：提高上尿路梗阻性无尿的认识和诊治水平。方法：回顾分析45例上尿路梗阻性无尿的梗阻原因和治疗方法。结果：肾功能恢复正常者34例,术后3个月仍有氮质血症9例。结论：上尿路梗阻性无尿以结石梗阻为主,占77.8％。膀胱镜下输尿管插管,置入双J管内支架引流手术是解除梗阻的主要方法。