The aetiological and clinical pattern of childhood urolithiasis in Saudi Arabia

The clinical and aetiological pattern in 85 stone-forming children presenting to an integrated nephrourological service in Riyadh is reviewed. All patients were below the age of 15 years, the male to female ratio being 2∶1. Only 2 children presented with bladder calculi. The remaining all had upper tract stone and, in 12 cases, these were bilateral. Of 34 calculi recovered for analysis, one-third was predominantly calcium oxalate and a further third was composed of uric acid or urate. Four patients had cystine stones and the remaining 7 presented mixed calcium stones, 6 (17.6%) being struvite and infection-related. Of the 85 patients 55 were treated successfully with extracorporeal shock wave lithotripsy, 16 underwent surgery and 7 had their stones removed by endourological procedures. In the remaining 7 children, stones dissolved or were passed spontaneously during medical therapy. Nine children (10.6%) showed a primary metabolic defect leading to their stone formation, 10 (11.8%) had a predisposing anatomical anomaly and 15 (17.6%) presented with urinary tract infection. Of the remaining 51 patients (60%) with idiopathic disease, 6 showed hypercalciuria on investigation and 2 children may have formed their stones due to prolonged recumbency.     

复杂性肾结石的早期诊断及预防

目的通过分析复杂性肾结石病史,结石成分等临床特点,为其诊疗及预防提供帮助。方法回顾性研究2009年8月至2010年5月于北京大学人民医院进修期间118例复杂性肾结石病例,对患者病史、既往史、结石化学成分及尿常规、肾功能等临床资料进行总结分析。结果118例患者中,7例(5.9%)接受过定期规律体检,97例(82.2%)从未曾接受过健康体检,64例(54.2%)曾有结石病史,86例(72.9%)以疼痛、血尿及发热等不适症状为主诉,92例(78.0%)伴有泌尿系感染,18例(15.3%)伴有肾功能不全,结石成分中含钙结石94例(79.7%),感染石55例(46.6%),含尿酸结石28例(23.7%)。结石以混合成分为主,其中感染石与草酸钙的混合成分所占比例最大,共51例(43.2%)。结论应通过定期规律体检提高早期诊断比例,控制结石进展,根据不同结石成分,采取有针对性的预防措施,同时必须重视抗感染治疗,以减少患者损伤,降低结石复发率。     

Clinical experience of extracorporeal shock wave lithotripsy for cystine calculi

Thirty patients (16 men and 14 women) with cystine urinary stones were treated by extracorporeal shock wave lithotripsy (Dormer HM-3) from December 1984 through October 1989. The average patient age was 35.2 years with a range of 14 to 59 years. Seventy per cent of these subjects had had previous open surgical operations for stones. The cases consisted of 7 ureteral stones and 37 renal stones, including 15 staghorn calculi. An average of 1.3 session of ESWL was carried out to treat ureteral stones. Thirty-seven renal units with renal stone required 96 sessions of lithotripsy (average 2.6 sessions per unit). Seven patients with ureteral stones required auxiliary procedures, i.e., one transurethral lithotripsy (TUL), two percutaneous nephrostomies (PNS) and one open surgery. Thirty-seven renal stones, including staghorn calculi was treated by ESWL and auxiliary treatment of 21 TUL procedures, one PNS, 16 PNL procedures and one chemical chemolysis. Successful fragmentation (residual debris less than or equal to 4 mm) was achieved in 85.7% of ureteral stones, 90.9% of renal stones and 73.3% of staghorn calculi. The stone free rates of patients with ureteral stones, renal stones and staghorn calculi were 71.4%, 50.0% and 53.5%, respectively, at 3 months after ESWL. No serious complications were seen in this series. Fever above 38.5 degrees C was the most common complications (13.5%). Ureteral perforation was encountered once in TUL procedures. Transfusion and selective arterial embolization were needed for one case treated by PNL procedures. Although cystine stone is harder to be fragmented by ESWL than other stone composition, ESWL and endourology may be effective and safe procedures for cystine stone patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

输尿管软镜碎石术治疗上尿路结石的疗效和安全性

目的探讨输尿管软镜碎石术(retrograde intrarenal stone surgery,RIRS)治疗上尿路结石的疗效和安全性。方法回顾性分析2016年4月至2019年1月武汉大学人民医院行RIRS的640例上尿路结石患者的临床资料。男424例,女216例。年龄(46.2±12.8)岁。结石最大径(1.4±0.7)cm。肾下盏结石126例,非肾下盏结石514例。单侧输尿管上段结石196例,单侧输尿管上段结石合并肾结石118例,单侧肾结石236例,双肾结石90例。104例术前留置双J管。马蹄肾8例,孤立肾合并肾功能不全30例,盆腔异位肾合并旋转不良4例,先天性输尿管畸形6例,海绵肾2例。术前血红蛋白(133.2±5.6)g/L,血清肌酐(84.4±12.2)μmol/L。手术均采用全麻,患者取截石位。采用输尿管软镜联合钬激光碎石,软镜顺利进入肾盂后首先观察肾盂及各肾盏并寻及结石。使用200μm光纤碎石,钬激光功率为12~45 W(0.5~1.5 J/10~30 Hz),根据实际情况辅助取石网篮套取结石。术中检查各肾盂、肾盏,确保结石已完全粉末化(结石最大径<0.3 cm),留置双J管和尿管。手术均由同等资历的术者完成。结果所有手术均顺利完成,手术时间(45.6±14.6)min。术后第1天复查血清肌酐(76.0±10.6)μmol/L,与术前比较差异有统计学意义(t=64.76,P<0.05);血红蛋白(126.4±9.6)g/L,与术前比较差异无统计学意义(t=2.02,P=0.064)。术后住院时间(4.8±1.5)d。术后3例(0.9%)发生严重并发症,分别为2例脓毒血症,1例包膜下血肿。术后3个月596例获得随访,其中552例达到结石清除标准,结石清除率(stone-free rate,SFR)为92.6%;余44例未达到结石清除标准者采用体外冲击波碎石、再次输尿管软镜手术或拔除双J管后观察。结石大小(χ^2=29.569,P<0.05)和位置(χ^2=44.949,P<0.05)是SFR的影响因素。多因素回归分析结果显示结石大小不是影响SFR的独立危险因素(P=0.639),结石位置是影响SFR的独立危险因素(P=0.013)。结论RIRS对于上尿路中小结石患者是一种可靠的治疗方式,疗效确切,并发症少,安全性高。但对于大结石及肾下盏结石的治疗还存在一定的局限性。肾下盏结石是影响RIRS疗效的独立危险因素。     

开放手术治疗上尿路结石667例回顾分析

目的 总结开放手术治疗上尿路结石的有效性,探讨在微创时代开放手术治疗上尿路结石的手术适应证.方法 回顾分析1995年1月至2004年12月在四川大学华西医院泌尿外科行开放手术治疗的上尿路结石病例.结果 共667例上尿路结石行开放手术治疗,同期约有9000例上尿路结石病例在我科治疗,开放手术比例约7.4%.开放手术原因包括:复杂结石及巨大结石297例,结石致患肾无功能137例,结石合并上尿路解剖畸形134例,微创治疗失败57例,结石合并各种内科疾病30例,结石合并肾肿瘤5例,结石合并黄色肉芽肿性肾盂肾炎3例,结石合并肾外伤2例,结石合并同侧其他手术2例.145例肾切除病例中共16例出现术中并发症,6例出现术后并发症;522例肾输尿管切开取石病例中,7例出现术中并发症,34例出现术后并发症;术后57例结石残留,总结石清除率为89.1%;围手术期无一例死亡.结论 开放手术在上尿路结石的治疗中仍然有重要作用,结石性无功能肾切除、复杂及巨大肾结石、结石合并解剖畸形、微创治疗失败及合并内科疾病的部分选择性病例适合选择开放手术治疗,治疗效果确切,并发症低.     

移植肾尿路结石的腔内治疗

目的探讨腔内治疗移植。肾尿路结石的效果和策略。方法采用腔内技术治疗13例移植。肾尿路结石，其中。肾结石3例，金属支架结石1例，输尿管结石9例，合并输尿管口狭窄2例。结石最大直径8～48mm，接受肾移植的时间1个月～8年。结果3例。肾结石和1例金属支架结石行经皮微造瘘输尿管镜取石术成功取石。4例输尿管结石行逆行输尿管镜取石治疗；3例行经皮顺行输尿管镜取石成功，其中1例合并移植输尿管口狭窄者同时行内切开取石；1例移植输尿管口狭窄合并下端结石者，改行开放手术；1例输尿管结石直接行体外冲击波碎石术2次后排净结石。术后随访1～8年，人肾存活均良好，12例患者。肾功能恢复正常，无结石复发。结论移植肾尿路结石处理应选择创伤小、效果好的腔内微创治疗，尽可能保护。肾功能。     

Management of impacted urethral stones in children

Objective: To find out the clinical presentation, site of impaction, management and outcome of children presenting with urinary retention due to urethral stone. Study Design: Case series. Place and Duration of Study: Surgical Unit B of National Institute of Child Health (NICH), Karachi, from April 2009 to January 2010. Methodology: All the patients under the age of 12 years, who presented with urinary retention due to impacted urethral stones were included. Urinary retention due to other causes like trauma, stricture, pelvic masses etc. were excluded. Diagnosis was made on clinical examination (palpable stone in penile urethra) and with the help of radiology. Surgical procedure was tailored according to the site of impaction in urethra. All stones were sent for chemical analysis and patients were followed in Nephrology OPD (stone clinic) for further work-up. Results: There were a total of 19 patients with mean age of 3.94 ± 2.27 years. All were males. Twelve patients (63.1%) had stones impacted in anterior urethra while 7 (36.9%) were found in posterior urethra. Stones in penile urethra were removed in emergency either by meatotomy (when impacted at urethral meatus, n = 3) or following initial supra-pubic decompression of urinary bladder (using wide bore cannula) by urethrolithotomy (n = 6). Stones in bulbous (n = 3) and posterior urethral (n = 7) locations were pushed back into bladder and later removed on elective list by supra-pubic vesicolithotomy. No patient had proximal urinary tract calculi on further work-up. All patients remained well except one who developed retention of urine after a week of discharge. He had urinary tract infection and was treated with antibiotics. All the stones were of calcium oxalate type. Conclusion: Urethral stones must be kept in differential diagnosis in a child who presents with acute urinary retention. Clinical examination can identify causes in significant number of cases. Simple procedures like meatotomy, supra-pubic bladder decompression and urethrolithotomy can relieve the misery in these children.     

延安地区泌尿系结石成分分析的研究

目的利用红外光谱法测定延安大学附属医院泌尿外科手术获得的泌尿系结石成分,探讨延安地区泌尿系结石成分与年龄、性别等关系,比较上、下尿路结石成分特点,分析延安地区泌尿系结石发生的流行病学情况,为临床制定有效的个体化治疗及预防措施提供参考依据。方法收集2013年1月至2017年1月在延安大学附属医院泌尿外科治疗1984例尿路结石患者的年龄、性别、结石部位等临床资料,对比分析延安地区泌尿系结石在不同年龄、不同性别、不同解剖部位的分布特点。结果在1984例泌尿系结石的患者中,按每10岁年龄大小分组排序,统计各年龄阶段泌尿系结石发病情况,男性患者有1346例,女性患者有638例,男性年龄(50.23±14.48)岁,女性年龄(47.87±14.51)岁,男、女患者比例约2.11∶1。在66~75岁年龄段,尿路结石发病率性别差异具有统计学意义(P<0.05)。结石成分以混合性结石为主,以混合性结石为主,共1582例,占79.76%。其中1665例(83.92%)为上尿路结石,上、下尿路结石的比例为5.22∶1,其余为肾结石合并膀胱结石。上尿路结石中男性1062例,女性603例,男女比例为1.76∶1;下尿路结石中男性284例,女性35例,男女比例为8.11∶1。青壮年(年龄≤45岁)泌尿系结石患者草酸钙为主结石、感染性结石多见;中老年(年龄>45岁)泌尿系结石者草酸钙为主结石、尿酸类结石多见。感染性结石患者性别差异具有统计学意义(P<0.05)。结论在延安地区男性较女性更容易患泌尿系结石。同时,不同年龄段结石构成成分具有差异。对于年龄≤45岁患者,主要以草酸钙为主结石、感染性结石多见,这与结石整体发病率基本一致;而对于年龄>45岁患者,主要以草酸钙为主结石、尿酸性结石多见。表明对于不同年龄段的结石患者,可以根据上述结果在结石的预防和治疗上综合考量,给予明确而更加合理的治疗。     

ESWL与输尿管镜碎石联合处理上尿路结石

目的：探讨对部分上尿路结石采用ESWI．与输尿管镜碎石联合处理的方法。方法：对70例上尿路结石患者采用ESWI。与输尿管镜下钬激光碎石（URS）联合交替治疗。其中输尿管结石48例,。肾结石22例。结果：结石总排净率为91．4％00（64／70）,其中输尿管结石排净率为95．8％（46／48）,肾结石排净率为81．8％（18／22）。3例治疗失败,其中1例输尿管结石因输尿管狭窄无法入镜;另2例肾结石,1例因交替治疗次数过多中途停止治疗,1例因结石硬度过大ESWI,不佳,均改为PCNL术。结论：ESW[。与URS联合交替进行的疗法处理上尿路结石,避免了创伤性治疗,扩大了ESWI,治疗范围,降低了URS手术难度,缩短了URS操作时间,提高了结石排净率,患者创伤微小、恢复快、并发症少,是治疗上尿路结石,特别是部分复杂性上尿路结石较理想的方法之一。     

影响第二次冲击波碎石术治疗上尿路结石患者成功的因素分析

目的 探讨影响第二次冲击波碎石术（extracorporeal shock wave lithotripsy, ESWL）治疗上尿路结石患者成功的因素。方法 回顾性分析2008年1月至2012年12月来本院接受第二次ESWL治疗的上尿路结石患者120例。根据患者上尿路结石有无完全排出分为成功组（n=80）和失败组（n=40）。回顾性分析所有患者的病历资料,相关因素分析包括性别、年龄、病程、BMI、结石侧别、结石位置、结石长度、结石宽度、结石数目、肾绞痛、血尿、肾积水程度、非增强螺旋CT值、冲击次数、冲击能量等指标。应用单因素、多因素非条件Logistic回归分析上尿路结石患者第二次ESWL治疗成功与否的危险因素分析。结果 120例上尿路结石患者临床特征显示,两组在病程、BMI、结石长度、结石宽度、结石数量、肾绞痛、肾积水程度、CT值、冲击次数方面差异有统计学意义（P＜0.05）,在性别、年龄、结石侧别、结石位置、血尿、冲击能量方面差异无统计学意义（P＞0.05）。经单因素、多因素 Logistic 回归分析结果显示,BMI偏高、结石长度＞2 cm、存在肾绞痛、肾积水程度严重、CT值＞750 HU会增加上尿路结石患者第二次ESWL治疗失败的风险（P＜0.05）。结论 临床医师利用ESWL第二次治疗上尿路结石患者过程中,应格外注意患者BMI、结石长度、肾绞痛、肾积水程度、CT值等关键指标。     

Results of 5,035 stone analyses: a contribution to epidemiology of urinary stone disease

Between 1978 and 1988 5,035 urinary calculi have been analysed by X-ray diffractometry. 1,615 of these stones have additionally been investigated by scanning electron microscopy (SEM). The overall sex-ratio was 1.86 (m/f). Ca-stones and uric acid containing stones are more frequent in male patients (m/f = 2.08 and 3.86, respectively) whereas infection stones and cystine stones show a higher rate of appearance in female patients (m/f = 0.6 and 0.88, respectively). The percentage of open surgery ranged about 30% in the first few years but decreased to 5-7% in the last few years due to the new methods of stone removal. The rate of occurrence of the crystalline phases does not differ remarkably from other statistics except for a higher incidence of apatite because of the high sensitivity of detection of this phase by SEM. The recurrence rate of brushite stones amounting to 66.7% is very high and exceeds even that of cystine stones (60.7%).     

Treatment of staghorn calculi. Strategies and results of the combined use of new technics

From January 1984 to June 1986, 270 patients with staghorn calculi were treated by ESWL, PCNL, or a combination of both. The indications were determined according to stone burden, distribution of stone load, architecture of the renal collecting system, radiopacity, and chemical composition of the calculi. Another group (83 patients) treated from January 1982 to October 1983 exclusively with open surgery was also examined. In a retrospective study, the treatment and follow-up data of the two groups were evaluated and compared. At discharge, 78 (29%) of the patients treated by the new techniques were free of stones, while 192 (71%) still had residual fragments in the kidney or in the ureter. Among the group treated by open surgery, 54 (65.1%) were free of stones at discharge, 17 (20.4%) still had residual fragments, and 12 (14.5%) had to undergo nephrectomy. The follow-up data (18 months n = 186) for the ESWL-PCNL-group revealed a stone-free rate of 54.8%. Residual fragments were observed in 40.3% and recurrent stone formation occurred in only 4.9%. Follow-up examination of group treated by open surgery (42 months, n = 61) revealed a stone-free rate of 72.1%, while residual stones persisted in 8.2% and recurrent stone formation occurred in 19.7%. The incidence of urinary tract infection was only 11.3% after ESWL/PCNL, as against 30% after open surgery. It is remarkable that 80% of the patients with residual fragments after ESWL-PCNL did not have any such symptoms as infection or colic.     

2015~2018年达州市尿路结石患者人口学特征及结石化学成分分析

目的对2015~2018年四川省达州地区尿路结石患者人口学特征及结石化学成分进行分析。方法选择2015年1月至2018年12月四川省达州市中西医结合医院进行治疗的583例尿路结石患者,经体外振动波碎石、手术、自排等方式获得结石标本583份进行研究。所有患者入组后均采集性别、年龄、居住地等一般资料,获取结石标本后以结石红外光谱自动分析系统对其化学成分进行分析。结果583例患者中单纯性结石289例(49.75%),二重混合性结石288例(49.40%),三重混合性结石6例(1.03%)。从结石成分分布上看草酸钙占比最高,为94.00%,其次是磷酸磷灰石37.04%、尿酸及尿酸铵14.92%。女性患者磷酸铵镁占比为4.31%,明显高于男性的1.35%(P<0.05)。其他成分不同性别患者分布情况差异无统计学意义(P>0.05)。60岁以下的患者结石成分为草酸钙占比为96.69%,明显高于60岁及以上者的89.55%(P<0.05)。其他成分不同年龄段患者分布情况差异无统计学意义(P>0.05)。城镇居民患者草酸钙、磷酸磷灰石占比分别为96.69%、40.38%,均明显高于农村居民的89.82%、28.74%(P<0.05)。其他成分不同居住环境患者分布情况差异无统计学意义(P>0.05)。结论四川达州地区尿路结石患者结石化学成分易草酸钙为主,其次为磷酸磷石灰石、尿酸及尿酸铵。不同性别、年龄、居住环境对尿路结石化学成分分布有一定的影响。     

Recurrence of upper urinary tract calculi

Treatment of upper urinary tract stones has changed greatly. The recurrence of calculi after the discharge was studied in the 634 patients with urolithiasis admitted to our department during the 9 years up to the end of 1984. The recurrence rate in the 325 cases followed for more than 3 months after the disappearance of the original stones, was 15.6% after 2 years, 27.6% after 5 year and 51.4% after 8 years. In recurrent stone formers, the rate of recurrence thereafter was greater than that of primary stone formers. The growth of calculi was rapid in the renal stone former concomitant with urinary tract infection together with a past history of renal surgery. In relation to the composition of the stone, uric acid calculi tended to recur more often than calculi composed of other substances. In view of recurrence, pyelolithotomy is preferred to renal parenchymal incision.     

Clinical studies on childhood urolithiasis during the past 22 years

We have studied retrospectively 68 children who presented with urolithiasis between 1965 and 1986. Male to female ratio was 1.83 to 1 and the mean age was 9.5 years. Fifty four children (79%) had calculi in the upper urinary tract, 9 (13%) had in the lower, and 4 (6%) had calculi both in the upper and lower urinary tract. The most common presenting symptoms were gross hematuria (53%) and abdominal or flank pain (38%). Predisposing factors could be found only in 21 children (31%). Twenty four of the 68 patients (35%) had open surgery and 16 patients (24%) passed their stones spontaneously. Twenty one stones were analyzed by infrared spectroscopy. Infectious stone was more frequent than in adult cases. Among children five years old and younger, infectious stone was the most frequent. Among children over five years old, the number of idiopathic calcium stone has been on the increase with the years.     

A study on bacteria within stones in urolithiasis

The bacteria in 37 stones obtained from 37 patients with urinary stone diseases, that is, 11 renal stones (containing 2 staghorn calculi), 21 ureteral stones, 4 bladder stones and 1 urethral stone, were studied, according to the Nemoy & Stamey's method. The stones were collected by partial nephrectomy (1 case), nephrolithotomy (1 case), pyelolithotomy (1 case), percutaneous nephrolithotripsy (PNL) (6 cases), 12 ureterolithotomies, transurethral ureterolithotripsy (2 cases), cystolithotripsies (4 cases) and spontaneous deliveries (10 cases). According to a stone analysis by infrared spectrophotometer revealed 30 were noninfection stones (81.1%) and 7 infection stones (18.9%). Of these 37 stones, 5 stones (13.5% of 11 stones) had bacteria within them. These stones consisted of 4 infection stones (57.1% of all infection stones) and 1 noninfection stone (3.3% of all noninfection stones). Out of 4 patients having bacteria within their stones, urine culture of whom were carried out before stones were collected, only one patient (25%) had the same species of bacterium (E. coli) both within the stone and in urine. The E. coli within the stone and that in urine, however, showed quite different reactions to some antibiotics. The fact that all organisms within stones cannot be detected by urine culture before collecting stones of the patients in our present study, suggests that patients undergoing endourological surgery, such as extracorporeal shock wave lithotripsy and PNL, may have a risk of complications, such as severe urinary tract infection and urosepsis, if the possibility of the presence of organisms within stones is not taken into consideration.     

Risk factors for developing renal stones in inflammatory bowel disease

OBJECTIVE: To correlate renal calculi and other clinical factors with urinary biochemical analytes in patients with inflammatory bowel disease, and to investigate the relative importance of hyperoxaluria (associated with fat malabsorption) or reduced stone inhibitors in the development of calculi in these patients. PATIENTS, SUBJECTS AND METHODS: Samples were obtained from 25 patients with Crohn's disease (CD), 15 with ulcerative colitis (UC) and 17 normal subjects (controls). Evidence for the presence of renal calculi was obtained from plain films, ultrasonography or intravenous urography. Urine oxalate and citrate were analysed using commercial enzymatic assays; magnesium was measured using atomic absorption and other analytes assayed using standard methods on automated analysers. RESULTS: Renal calculi were found in two patients with CD and in none with UC. Hyperoxaluria was present in 36% of patients with CD but was absent in those with UC. Analysis of covariance showed an association between low urinary citrate/creatinine ratio and renal stones (P=0.02), and between a combined urinary citrate and magnesium deficit relative to calcium, as expressed in the CMC index ((citratexmagnesium)/calcium), and renal stones (P=0.017). Changes in urinary calcium, oxalate, urate, magnesium or the calcium oxalate index were not associated with the presence of stones. There was no independent relationship between any clinical factor and the presence of stones. CONCLUSION: Lower urinary concentrations of magnesium and citrate (stone inhibitors), relative to calcium (stone promoter; the CMC index) may be more important in lithogenesis in inflammatory bowel disease than is hyperoxaluria. In patients with a functioning colon, a low CMC index may predict likely stone-formers; this requires a prospective evaluation. Avoiding low urinary levels of magnesium and citrate may aid in preventing and treating renal calculi.     

川西地区500例泌尿系结石成分构成及相关因素分析

目的：探讨川西地区泌尿系结石的成分构成及其相关因素。方法：前瞻性收集2011年11月～2013年11月经确诊为泌尿系结石的患者500例,采用红外光自动分析仪（LIIR一20型）分析结石成分构成。用SPSS13．0软件描述性分析相关研究指标。结果：泌尿系结石患者的性别比（男：女）为1．86：1,且以中青年（29～48岁）居多（46．8％）。少年患者以肾结石为主（55％）,青年、中年和老年患者以输尿管结石为主（分别占69．9％、65．2％和53．6％）。泌尿系结石成分主要为纯一水草酸钙（28．4％）,但青年患者以混合结石（一水草酸钙／二水草酸钙和碳酸）居多（38．2％）。汉族患者结石成分主要为纯一水草酸钙（29．8％、）;藏族多为混合结石（38．0％）。结论：川西地区泌尿系结石成分主要为草酸钙,且具有民族和地区差异,建议针对结石成分的特点采取相应的预防和治疗措施。     

Hounsfield units on computerized tomography predict stone-free rates after extracorporeal shock wave lithotripsy

PURPOSE: Studies suggest that HU values on non-contrast computerized tomography may predict the ability to fragment urinary calculi. We determined whether the HUs of in vivo urinary stones could be used to predict the stone-free rates after extracorporeal shock wave lithotripsy. MATERIALS AND METHODS: We evaluated 50 patients who underwent extracorporeal shock wave lithotripsy for 5 to 10 mm. upper urinary tract stones. Chemical analyses and HU calculations were performed for each stone and posttreatment radiographic assessment categorized patients into a stone-free or a residual stone group. Statistical analysis was performed using the Student t test to compare mean HU values in the 2 groups. RESULTS: Of the patients 32 (64%) were stone-free and 18 (36%) had residual stones. Mean values +/- SEM for the stone-free and residual stone groups were significantly different (551.20 +/- 46.66 versus 926.20 +/- 51.42 HU, p <0.0001). A total of 30 calculi (60%) were located in the ureter, including 21 in the stone-free group and 9 in the residual stone group with a mean value of 505.10 +/- 46.66 and 888.70 +/- 102.00 HU, respectively, which was significantly different (p = 0.0005). A total of 20 calculi (40%) were located in the kidney, including 11 in the stone-free group and 9 in the residual stone group with a mean value of 558.40 +/- 62.38 and 905.10 +/- 61.49 HU, respectively, which was significantly different (p = 0.001). CONCLUSIONS: These findings suggest that HU measurement of urinary calculi on pretreatment non-contrast computerized tomography may predict the stone-free rate. This information may be beneficial for selecting the preferred treatment option for patients with urinary calculi.     

Prediction of calcium level in melamine-related urinary calculi with helical CT: diagnostic performance evaluation and clinical significance

The aim of the study was to investigate the relationship between CT-attenuation and stone calcium level in melamine-related urinary calculi (MRUC). A total of 25 MRUC with known composition and calcium level were included (11 uric acid stones, 2 calcium oxalate stones and 12 mixture stones of uric acid and calcium oxalate). Of all, 18 renal stones accepted alkalization therapy except for 5 lower urinary tract stones and 2 stones of unknown position. With well-matched composition, 61 adult urinary stones were included as controls. Every stone was scanned by helical CT (80 kV/120 kV, 300 mA, pitch 0.625 mm) and the highest CT-attenuation value measured. CT-attenuation values of MRUC increased gradually from uric acid stones, mixture stones to calcium oxalate stones, but were always lower than the values of controls. Furthermore, a strong positive correlation was found between stone CT-attenuation value and stone calcium level (n = 25, r (80kV) = 0.883, p = 0.000; r (120kV) = 0.855, p = 0.000). Compared with alkalization-therapy-alone group, stone CT-attenuation values and stone calcium level in the comprehensive-therapy group were significantly greater (CT(80kV) 1,057 ± 639 vs. 172 ± 61 HU, p = 0.001; CT(120kV) 783 ± 476 vs. 162 ± 60 HU, p = 0.001; Ca 19.83 ± 7.48% vs. 1.30 ± 1.51%, p = 0.000). Fisher's exact test suggested that the stones with higher CT-attenuation values tended to resist alkalization when 400 HU served as the cutoff value (P (80kV) = 0.002, P (120kV) = 0.000). In conclusion, the study was the first to illustrate that the CT-attenuation value could reflect calcium level in MRUC and found that stones with higher CT-attenuation value were not amenable to alkalization because they probably contained greater calcium. For those patients, we believe that comprehensive therapy will be the best choice.