Left testicular artery arching over the ipsilateral renal vein

Aim:To report two cases of the left testicular artery arching over the left renal vein(LRV)before running downwardto the testis.Methods:The subjects were obtained from two Japanese cadavers.During the student course ofgross-anatomical dissection,the anatomical relationship between the testicular vessels and the renal vein was specifi-cally observed.Results:The arching left testicular artery arose from the aorta below the LRV and made a looparound the LRV,which appeared to be mildly compressed between the arching artery and the psoas major muscle.Conclusion:Clinically,compression of the LRV between the abdominal aorta and the superior mesenteric arteryoccasionally induces LRV hypertension,resulting in varicocele,orthostatic protenuria and hematuria.Consideringthat the incidence of a left arching testicular artery is higher than that of a right one,an arching left artery could be anadditional cause of LRV hypertension.(Asian J Androl 2006 Jan;8:107-110)     

Total ligation of the left renal vein in the dog: an inappropriate model for varicocele

Induction of varicocele was attempted by ligation of the left renal vein (LRV) in male dogs (Group I). Before the operation and in the 4-month post-operative period, sperm count, sperm motility, and sperm morphology of Group I (n = 8) dogs were compared to sham operated animals (Group II, n = 5). Furthermore, haemodynamics as well as testicular and vascular morphology were studied. In Group I, changes in diameter and consistency of the spermatic cord were temporary. Semen quality was reduced significantly during the second month after ligation of the LRV, but improved thereafter. Haemodynamic studies revealed that LRV blood pressure was increased significantly in Group I dogs. An extensive venous collateral network replaced the occluded LRV. Retrograde blood flow in the left testicular vein (LTV) was observed only in the proximal part of the LTV of Group I dogs. In Group II dogs numerous pairs of sufficient valves prevented reflux into the LTV. Histological examination revealed that spermatogenesis was not impaired and that the left pampiniform plexus had not changed. The number of Leydig cells was decreased slightly in Group I dogs. Sufficient valves in the LTV prevented formation of a permanent varicocele.     

Diagnosis of nut-cracker phenomenon using renal Doppler ultrasound in orthostatic proteinuria.

BACKGROUND: We evaluated the efficacy of non-invasive renal Doppler ultrasound (US) to detect the nut-cracker phenomenon (NCP) and we studied the prevalence of NCP in children with orthostatic proteinuria. METHODS: Among a total 66 cases of orthostatic proteinuria, 39 cases of NCP were found, with 27 cases being detected in a normal control group. Using Doppler US, the anteroposterior (AP) diameter and peak velocity (PV) of the left renal vein (LRV) were measured at the hilar and aortomesenteric portion. We calculated the ratio of AP and PV diameters between the two portions. The parameters were analysed using Student's t-test. RESULTS: The AP diameters and the ratio in the hilar and narrow portions were all significantly different between the two groups (P<0.01). The PV in the narrow portion and the ratio of PV were significantly different (P<0.01), but the PV in the hilar portion was not statistically different between the two groups (P>0.05). If the diagnostic criteria for NCP was that the ratio of PV was more than 5, then 22 subjects (56.4%) in the orthostatic proteinuria group and none in the control group could be diagnosed as NCP. If, however, the cut-off values for the diagnosis of NCP were set at the mean+/-2 SD of the ratio (PV ratio 3.98 and size ratio 4.16), then the orthostatic proteinuria group showed abnormal AP diameter in 25 (64.1%), peak velocity in 28 (71.8%), and both in 21 patients (53.8%), and the control group showed an abnormal AP diameter in one subject (3.7%). CONCLUSIONS: NCP may be one of the leading causes of orthostatic proteinuria, and non-invasive renal Doppler US may be a useful diagnostic tool in the screening of NCP. In the future, the diagnostic criteria of NCP must be redefined in children.     

Renal vein entrapment syndrome: frequency and diagnosis. A lesson in conservatism

Two boys investigated for gross hematuria and left loin pain were found on ultrasound (US) to have left renal vein (LRV) entrapment associated with isomorphic urinary red blood cells, but normal renal venograms. Over the next 18 months ten children with gross hematuria were investigated and two more boys were discovered with the LRV entrapment syndrome, i.e., isomorphic red cells and a diagnostic US. Venography has a low yield in detecting renal venous compression, and since urinary red cell morphology may localize the origin of renal bleeding, we strongly recommend simple procedures, i.e., phase microscopy and renal US to evaluate all cases of hematuria before employing invasive or radiation dependent investigations. Since there is a range of LRV compression and associated dilatation in asymptomatic patients, strict criteria must be applied to diagnose renal vein entrapment.     

Intra-arterial digital subtraction angiography for children with idiopathic renal bleeding: a diagnosis of nutcracker phenomenon

Among children with asymptomatic hematuria, 28 cases of nonglomerular idiopathic renal bleeding were subjected to this series of study. Intra-arterial digital subtraction angiography (DSA) and/or renal venography were performed to investigate the hematuria of unknown etiology. DSA clearly demonstrated the entrapment of the left renal vein (LRV), or nutcracker phenomenon in the majority of our patients (22 out of 28 cases): obstruction of the LRV with well-developed collaterals were found in 8 cases, and in the remaining 14 cases, various degrees of LRV compression were demonstrated. A characteristic real-time DSA image was the congestion of LRV associated with collaterals and/or intermittent venous flow at the compressed segment of LRV. The pullback pressures from LRV to the inferior vena cava (IVC) that were obtained from 5 of these patients demonstrated gradients of 2 mmHg (3 cases), 3 mmHg (1 case), and 5 mmHg (1 case), respectively. The parallel application of ultrasonography has given positive signs for LRV entrapment, although they have not necessarily coincided with the existing criteria of nutcracker phenomenon. Considering the high incidence of LRV entrapment among children with nonglomerular hematuria, most nutcracker phenomenon should be diagnosed on ultrasonography. However, intra-arterial DSA is an important tool to establish the disease entity and ultrasonic criteria.     

Left renal vein obstruction associated with nonrenal malignancy: Detection by computed tomography and ultrasonography

Left renal vein (LRV) obstruction may result from retroperitoneal spread of nonrenal malignancy. Whereas, heretofore, renal venography has been necessary to confirm such an obstruction, computed tomography (CT) and ultrasonography (US) are presently the noninvasive imaging modalities of choice to substantiate the diagnosis. In 7 patients with LRV obstruction associated with carcinoma of the pancreas or lung or lymphoma, excretory urography (EU) demonstrated slight enlargement of the left kidney with attenuation of its pyelocalyceal system. Two patients showed ureteral notching. CT, performed in 6 patients, revealed retroperitoneal mass adjacent to the LRV in 5 and LRV dilatation in 3. Small round or tubular densities representing collateral veins were visualized medial to the left kidney in 3 patients. US, performed in 3 patients, revealed a generalized increase in renal parenchymal echogenicity, a mass adjacent to the LRV in 2 and an LRV clot in 1.     

彩超及CTA对胡桃夹综合征的诊断价值

目的探讨彩超及CTA对胡桃夹综合征（NCS）的诊断价值。方法分析50例NCS患者及50例健康人的资料。结果主诉肉眼及镜下血尿31例;疲乏伴纳差4例;左精索静脉曲张10例;蛋白尿伴左腰不适5例。13例女性有盆底淤血征,男性均有不同程度左精索静脉曲张。彩超肠系膜上动脉（SMA）和腹主动脉（AO）夹角（a）（25.08±11.83）°vs.（48.73±25.82）°;左肾静脉（LRV）受压管径（D1）（2.45±1.28）vs.（3.48±1.02）cm,血流速度（V1）（0.38±0.16）vs.（0.48±0.13）m/s;LRV远端管径（D2）（8.55±2.63）vs.（7.43±2.03）cm,血流速度（V2）（0.28±0.21）vs.（0.94±0.43）m/s。21例CTA示SMA与AO夹角减小,1例示胰头部压迫,3例SMA分支及下方纤维结构压迫;1例后胡桃夹征（腹主动脉和脊柱之间压迫）,15例膀胱镜左输尿管口喷血。结论彩超初步筛选胡桃夹征,CTA更清晰显示LRV周围结构。     

Entrapment of left renal vein in children with orthostatic proteinuria

We found that patients with orthostatic proteinuria had entrapment of the left renal vein (LRV) by the aorta and superior mesenteric artery (SMA). Of 15 patients studied, ultrasonographic examination showed 13 cases of typical LRV entrapment with prestenotic dilatation, and 2 cases of mild LRV compression between the aorta and SMA. Intra-arterial digital subtraction angiography and monitoring of pull-back pressure from LRV to the inferior vena cava (IVC) were performed on 2 patients with 4+ proteinuria. Accumulation of contrast medium was seen with mild back-flow to the collateral veins, and pressure gradients between LRV and IVC were 4 mmHg and 8 mmHg, respectively. Eighty school-children formed a control group and were investigated ultrasonically. Nine showed typical LRV entrapment, among whom 3 had moderate to massive orthostatic proteinuria. The discovery of LRV entrapment in patients with orthostatic proteinuria gives definite evidence of LRV congestion and may be possibly a cause of massive protein secretion from the left kidney.     

腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床分析

目的 探讨腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床疗效.方法 左肾静脉压迫综合征患者5例.男4例,女1例.年龄20～35岁,平均25岁.肉眼血尿3例,活动后加重,合并蛋白尿1例;左腰酸痛伴左精索静脉曲张2例.术前彩色多普勒超声及CT三维血管重建均提示左肾静脉压迫明显.扩张段与受压段直径比值均＞3.膀胱镜检查3例可见左输尿管口喷血尿.5例均于全麻下行腹腔镜下左肾静脉受压段外支架固定术治疗,术中用人造血管固定于下腔静脉与生殖静脉之间形成血管外支架以克服左肾静脉受压.结果 5例手术均顺利完成.手术时间65～70 min,平均67 min.术中出血量10～15 ml,平均13 ml.术中术后无明显外科并发症,术后恢复顺利,术后5～6 d出院.肉眼血尿消失3例,左精索静脉曲张减轻2例.术后随访9～39个月,平均28个月,1例术前肉眼血尿、术后仍有轻微镜下血尿,4例尿常规检查正常.5例其余症状均消失,超声检查示左肾静脉血流通畅、受压现象消失.结论 腹腔镜下左肾静脉外支架固定术采用人造血管环绕左肾静脉抵抗肠系膜上动脉压迫,是治疗左肾静脉压迫综合征的一种可供选择的微创技术,手术简单、方便、安全有效,创伤小、痛苦少、恢复快.     

腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床分析

目的 探讨腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床疗效.方法 左肾静脉压迫综合征患者5例.男4例,女1例.年龄20～35岁,平均25岁.肉眼血尿3例,活动后加重,合并蛋白尿1例;左腰酸痛伴左精索静脉曲张2例.术前彩色多普勒超声及CT三维血管重建均提示左肾静脉压迫明显.扩张段与受压段直径比值均＞3.膀胱镜检查3例可见左输尿管口喷血尿.5例均于全麻下行腹腔镜下左肾静脉受压段外支架固定术治疗,术中用人造血管固定于下腔静脉与生殖静脉之间形成血管外支架以克服左肾静脉受压.结果 5例手术均顺利完成.手术时间65～70 min,平均67 min.术中出血量10～15 ml,平均13 ml.术中术后无明显外科并发症,术后恢复顺利,术后5～6 d出院.肉眼血尿消失3例,左精索静脉曲张减轻2例.术后随访9～39个月,平均28个月,1例术前肉眼血尿、术后仍有轻微镜下血尿,4例尿常规检查正常.5例其余症状均消失,超声检查示左肾静脉血流通畅、受压现象消失.结论 腹腔镜下左肾静脉外支架固定术采用人造血管环绕左肾静脉抵抗肠系膜上动脉压迫,是治疗左肾静脉压迫综合征的一种可供选择的微创技术,手术简单、方便、安全有效,创伤小、痛苦少、恢复快.

Abstract：

Objective To report the experience in the use of laparoscopic extravascular stent for the treatment of the nutcracker syndrome. Methods Five patients (4 men and 1 woman) aged 20 to 35 years (mean 25) underwent laparoscopic extravascular stent of the left renal vein (LRV) for treatment of nutcracker syndrome associated with severe recurrent gross hematuria and left gonadal vein varices. All patients met the criteria for establishing the diagnosis of nutcracker syndrome. Ultrasonography, computed tomography, and magnetic resonance imaging revealed visible entrapment of the LRV between the superior mesenteric artery and aorta. Bleeding from the left ureteral orifice was detected by cystoscopy in 3 cases. An externally reinforced graft was selected to form an external stent around the LRV to relieve the compression. Results The mean operation time was 67 min (65-70min). No complications occurred during surgery. The postoperative follow-up was 9 to 39 months (mean 28). Total relief was achieved in 4 men without a relapse of symptoms and abnormalities were not found in urine tests. There was partial relief for the female patient due to microscopic hematuria after the operation. In all the 5 cases, Color Doppler ultrasonography showed that the blood outflow was smooth, the inner diameter and flow velocity of the aortomesenteric portion of the LRV were both decreased, and the gonadal vein varices had diminished in diameter. Conclusions The laparoscopic extravgscular stent of the renal vein could be a feasible approach for re-establishing free renal venous outflow in patients with nutcracker syndrome. This slightly invasive treatment could eliminate the symptoms of the condition.     

腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床分析

目的 探讨腹腔镜下左肾静脉外支架固定术治疗左肾静脉压迫综合征的临床疗效.方法 左肾静脉压迫综合征患者5例.男4例,女1例.年龄20～35岁,平均25岁.肉眼血尿3例,活动后加重,合并蛋白尿1例;左腰酸痛伴左精索静脉曲张2例.术前彩色多普勒超声及CT三维血管重建均提示左肾静脉压迫明显.扩张段与受压段直径比值均＞3.膀胱镜检查3例可见左输尿管口喷血尿.5例均于全麻下行腹腔镜下左肾静脉受压段外支架固定术治疗,术中用人造血管固定于下腔静脉与生殖静脉之间形成血管外支架以克服左肾静脉受压.结果 5例手术均顺利完成.手术时间65～70 min,平均67 min.术中出血量10～15 ml,平均13 ml.术中术后无明显外科并发症,术后恢复顺利,术后5～6 d出院.肉眼血尿消失3例,左精索静脉曲张减轻2例.术后随访9～39个月,平均28个月,1例术前肉眼血尿、术后仍有轻微镜下血尿,4例尿常规检查正常.5例其余症状均消失,超声检查示左肾静脉血流通畅、受压现象消失.结论 腹腔镜下左肾静脉外支架固定术采用人造血管环绕左肾静脉抵抗肠系膜上动脉压迫,是治疗左肾静脉压迫综合征的一种可供选择的微创技术,手术简单、方便、安全有效,创伤小、痛苦少、恢复快.     

Preoperative and intraoperative evaluation of diameter-reflux relationship of calf perforating veins in patients with primary varicose vein

OBJECTIVE: Interruption of incompetent perforating veins (PVs) is important for varicose vein surgery. The purpose of this study was to evaluate the preoperative and intraoperative diameter-reflux relationship of PVs and to evaluate the accuracy of preoperative duplex scanning in patients with varicose vein. METHODS: Patients with primary varicose veins were retrospectively investigated. Diameters and reflux of PVs were evaluated before surgery with color flow duplex ultrasound scan (US). During operation, the incompetent PVs were defined as those that showed an outward spurt of blood flow from the stump of the PVs. The sensitivity and specificity of US in the detection of reflux of PVs were calculated. Competent versus incompetent vein diameters were compared with the Student t test and one-way analysis of variance. RESULTS: Three hundred twenty-four calf PVs were detected in 304 legs of 175 patients with varicose vein. Diameters of competent and incompetent PVs confirmed with intraoperative finding averaged 2.67 +/- 1.10 mm (n = 28) and 3.28 +/- 1.01 mm (n = 58), respectively, at the upper calf (P =.012), 2.85 +/- 0.85 mm (n = 53) and 3.68 +/- 0.94 mm (n = 137), respectively, at the lower calf (p <.001), and 2.67 +/- 0.99 mm (n = 14) and 3.27 +/- 0.66 mm (n = 22), respectively, at the posterior calf (P =.036). The overall sensitivity of detection of reflux with US was 87.7%, and the specificity was 75.3%. Diameters of true-incompetent PVs and false-incompetent PVs were 3.59 +/- 0.94 mm (n = 199) and 3.31 +/- 0.84 mm (n = 24), respectively (P =.157). Diameters of true-competent PVs and false-competent PVs were 2.61 +/- 0.91 mm (n = 73) and 2.89 +/- 0.82 mm (n = 28), respectively (P =.158). CONCLUSION: Although the diameter of incompetent PVs was larger than that of competent PVs in both US and intraoperative findings, diameter measurement alone can not completely distinguish competent and incompetent PVs. The sensitivity and specificity of reflux obtained with US showed that the accuracy of preoperative duplex scanning to evaluate PV competency was not sufficient.     

Hemodynamics of the varicocele. Part I. Correlation among the clinical, phlebographic and scintigraphic findings

To determine whether the varicocele results from collateral circulation partially replacing an obstructed left renal vein, we developed a scintigraphic technique that provides not only information about the velocity of retrograde flow in the testicular veins but also quantitative information about the size of the varicocele. The reliability of this method was assessed by comparison with the results of phlebography and the clinical diagnosis in 104 patients. Furthermore, the diameter of the left testicular vein was determined on the phlebogram. Good correlation was found among the velocity of the retrograde flow in the left testicular vein, the size of the varicocele and the diameter of the left testicular vein.     

不阻断肾动脉的胡桃夹现象的手术治疗

目的：提高对胡桃夹现象（左肾静脉压迫综合征）的认识，改进治疗胡桃夹现象的手术方法。方法：对2例临床主要表现为反复发作肉眼血尿、1例表现为重度左侧精索静脉曲张的胡桃夹现象患者均行不阻断动脉的左肾静脉重建术，即在生殖腺静脉、肾上腺静脉与腔静脉之间阻断肾静脉，阻断部分腔静脉，袖状切除肾静脉起始处的腔静脉，将肾静脉下移并与纵形切开的腔静脉相吻合。结果：3例术后血尿均消失，曲张的精索静脉消失，术后尿量、肌酐均无变化，痊愈出院，平均随访6个月（2～12个月），症状均无复发。结论：左肾静脉重建手术是治疗血尿的有效方法，掌握熟练的血管吻合技术情况下，不阻断肾动脉在生殖腺和。肾上腺中央静脉以近阻断肾静脉进行肾静脉重建术是可行的，肾脏无冷热缺血时间，从而可减少肾功能损害。     

Induction of varicocele in the dog: I. Partial ligation of the left renal vein does not induce a varicocele in the dog

Induction of varicocele was attempted by partial ligation of the left renal vein in 10 male dogs. The effects on sperm count, sperm motility, and sperm morphology, as well as on hemodynamics, were assessed. Furthermore, testicular, vascular, and kidney morphology was studied. Changes in the diameter and consistency of the left spermatic cord were found to be temporary. Total sperm count, sperm motility, and the total number of oval forms were not significantly altered. Hemodynamic studies revealed a renocaval pressure gradient, but retrograde flow in the distal part of the left testicular vein could not be observed by arteriography. A collateral network was found to compensate for the restricted left renal vein. Histologic examination revealed no damage to the seminiferous epithelium. Changes were not found in the kidney and left pampiniform plexus. Although some temporary changes induced by the partial ligation of the left renal vein are suggestive of varicocele, this hemodynamic study shows that the presented dog model does not mimic varicocele as encountered in man.     

Intravascular pressure measurements and phlebography of the renal vein: a contribution to the etiology of varicocele

Phlebography of the left renal vein was performed in 80 patients with left-sided varicocele demonstrating the nutcracker phenomenon. In 39 cases we could prove a compression of the left renal vein. In 10 varicocele patients additional intravascular pressure measurements were studied in both renal veins in the supine and erect position. We found no significant difference between the pressure in the left and right renal vein in the supine position: values varied with respiration. Changing from the supine to the erect position one can note a significantly elevated pressure, higher on the left side than on the right side due to the longer excursion of the left kidney. Urine investigations were done in 153 patients before and in 191 after sclerotherapy to detect protein or blood. Only in 4 patients we found proteinuria but no microhematuria. The results suggest that the aetiology of the varicocele formation is not the nutcracker phenomenon or renal vein hypertension; the predominant cause is a congenital incompetence of the valves in the left testicular vein. The driving force for the retrograde blood flow from the left renal vein into the testicular vein was the increase in pressure: in the supine position caused by respiration, the continuous reflux in the erect position caused by the hydrostatic pressure. The varicocele does not cause a congested kidney with hematuria and proteinuria.     

左肾静脉压迫综合征的手术治疗(附四例报告)

目的　探讨左肾静脉压迫综合征 (胡桃夹现象 )的临床特点及诊治方法。　方法　左肾静脉压迫综合征男性患者 4例 ,年龄 16～ 2 2岁。临床主要表现为反复发作肉眼血尿 ,1例合并左侧精索静脉曲张。膀胱镜下均可发现左侧输尿管口喷血尿 ,B超及CT三维重建示腹主动脉与肠系膜上动脉夹角处左肾静脉明显受压 ,肾静脉近端扩张。结合文献讨论其发病特点 ,影像学特征和治疗。　结果　 4例患者术前均明确诊断 ,均行左肾静脉重建手术 ,术后血尿消失 ,痊愈出院。术后 6个月及 9个月分别复查B超、CT三维血管重建 ,4例患者肾脏大小正常 ,重建肾静脉通畅 ,受压现象消失 ,尿常规正常。　结论　左肾静脉压迫综合征临床特点为肾静脉高压 ,肉眼或镜下血尿 ,精索静脉曲张。左肾静脉重建手术是治疗血尿的有效方法。     

Radiologically assessed testicular changes in infertile males with varicocele

The aim of this study was to assess vascular disturbances in the testis of infertile males associated with varicocele. In total, 124 consecutive male subjects were divided into the following groups: healthy fertile controls (n = 10), Gp1 (n = 28); infertile males with subclinical varicocele, Gp2 (n = 26); infertile males with grade I left varicocele, Gp3 (n = 28); infertile males with grade II left varicocele and Gp4 (n = 32); infertile males with grade III left varicocele. They were subjected to colour duplex for pampiniform plexus and scrotal scintigraphy. There was significant decrease in arterial blood velocity, testicular arterial diameters and testicular perfusion especially in high grade varicocele compared with healthy controls. The mean vein diameter demonstrated significant negative correlation with arterial diameter, arterial blood velocity, perfusion index, testicular size and significant positive correlation with perfusion index. The mean testicular size demonstrated significant positive correlation with arterial blood velocity, perfusion index and nonsignificant correlation with arterial diameter. It is concluded that there are significant decreases in testicular volume, testicular perfusion, blood velocity and testicular artery diameter in infertile males with varicocele.     

左肾静脉压迫综合征(附10例报告)

目的　提高左肾静脉压迫综合征的诊治水平。　方法　回顾性分析 10例左肾静脉压迫综合征患者的临床资料。男 9例 ,女 1例。年龄 14～ 37岁 ,平均 2 4岁。临床表现血尿 7例 ,蛋白尿2例 ,血尿合并蛋白尿 1例。彩色多普勒超声示左肾静脉扩张段直径均为受压狭窄处 3倍以上 ,9例行磁共振血管成像 (MRA)示左肾静脉受压。　结果　患者行左肾静脉内支架植入术 7例 ,肠系膜上动脉切断再吻合术 3例 ,手术均获成功。术后电话或门诊随访 1～ 5年 ,患者症状消失 ,左肾静脉无明显受压。　结论　左肾静脉压迫综合征临床表现多为非肾小球性血尿或直立性蛋白尿。多普勒超声、MRA及膀胱镜检查结合临床症状并除外其他疾病可作出诊断。一般行保守治疗随访观察 ,对有肾功能损害或有并发症者行外科手术或介入治疗。     

Variability of venous anatomy of rat testis: application to experimental testicular surgery.

The venous drainage of the testis of the laboratory rat was observed in 31 animals. The right testicular (internal spermatic) vein drained directly into the right common iliac vein in 77.4%, and into the inferior vena cava in 22.6% of the animals. The left testicular vein drained into the left common iliac vein in all animals, but in 90.3% there was also an accessory branch of the testicular vein draining into the left renal vein. These observations suggest that in the rat the exact anatomy of the venous drainage of each testis should be identified prior to undertaking any surgical procedure on the testis where the venous vasculature plays a major role such as testicular transplantation or the creation of an experimental varicocele.