The oblique supine decubitus position: technical description and comparison of results with the prone decubitus and dorsal supine decubitus positions

Our objective was to analyze the advantages of the percutaneous nephrolithotomy in oblique supine decubitus compared to the prone and dorsal supine position. In 87 patients diagnosed with urolithiasis (495.5–530.8 mm²), percutaneous nephrolithotomy (PNL) was performed from 2000 to 2011. The patients were divided into three groups: Group A, 32 patients, PNL in the prone decubitus position; Group B, 24 patients, PNL in the dorsal supine position; Group C, 31 patients, PNL in the oblique supine position. We analyzed intraoperative parameters, complications, and results among the three groups. The three procedures were performed with a single access, 24-30 Ch. No statistically significant differences were found among the three groups regarding the patients’ characteristics, or the morphology or size of the kidney stone treated. The operation time was shorter in the cases of PNL in dorsal supine and oblique supine compared to the prone position. The complication rate was very similar in the three groups. The main advantage of the PNL in oblique supine compared to the dorsal supine was that the puncture could in all cases be directed by ultrasonography, with greater precision, more safety, and more control of the percutaneous renal access. The oblique supine decubitus position is a safe position for the percutaneous treatment of urolithiasis and it becomes easier when the puncture is guided by ultrasound.     

A study on comparative outcomes of percutaneous nephrolithotomy in prone, supine, and flank positions

Purpose

To compare percutaneous nephrolithotomy (PCNL) safety and efficacy in prone, supine, and flank positions.

Methods

A total number of 150 candidates for PCNL were randomly assigned into prone, supine, and flank groups. Patients in groups 1 and 2 underwent fluoroscopy-guided PCNL in prone and supine positions, respectively, while patients in group 3 underwent ultrasonography-guided PCNL in lateral position.

Results

The success rates were 92, 86, and 88 % in prone, supine, and flank positions, respectively (P = 0.7). The mean access duration was 6.9 ± 4.2, 11.1 ± 5.8, and 10.8 ± 4.1 min (P = 0.08), and the mean operation time was 68.7 ± 37.4, 54.2 ± 25.1 and 74.4 ± 26.9 min (P = 0.04) in prone, supine, and flank groups, respectively. Pyelocaliceal perforation occurred in 2 (4 %), 2 (4 %), and 3 (6 %) patients in prone, supine, and flank positions, respectively (P = 1).

Conclusion

We believe that PCNL in both supine and flank positions are as safe and relatively effective as prone position in experienced hands. Preference of the surgeon and proper case selection for each procedure is very important and necessary.     

Lower intracuff pressure of laryngeal mask airway in the lateral and prone positions compared with that in the supine position

We compared the intracuff pressure (ICP) of a laryngeal mask airway (LMA) in the lateral and prone positions with that in the supine position. One hundred and eight patients, weighing 50-70 kg, scheduled for elective orthopedic and plastic surgery, were assigned to three groups, based on their body position during surgery. General anesthesia was induced and then a size 4 deflated LMA was inserted in each patient in the supine (group 1; n = 42), lateral (group 2; n = 45), or prone position (group 3; n = 21). The LMA cuff was inflated with 15 ml of air. Anesthesia was maintained without nitrous oxide, and the ICP was measured until LMA removal in the supine position. ICP in groups 2 and 3 was significantly lower than that in group 1 from immediately after insertion to the end of surgery. After surgery, turning from the lateral (group 2) or prone (group 3) position to the supine position significantly raised the ICP. Because the ICP is related to the seal pressure of the LMA and postoperative pharyngolaryngeal morbidity, we recommend evaluating and adjusting the ICP appropriately in each body position.     

仰卧位和俯卧位测量青少年特发性脊柱侧凸患者胸主动脉与椎体毗邻关系的差异

目的　通过术前仰卧位MRI和术中俯卧位O形臂X线机获得青少年特发性脊柱侧凸(AIS)患者横断面影像学资料,探讨2种体位下主胸弯顶椎与胸主动脉的毗邻关系。方法回顾性分析2013年4月—2018年7月美国梅奥医学中心骨科采用后路手术治疗的18例AIS患者资料。患者术前均行仰卧位全脊柱MRI平扫和术中俯卧位脊柱O形臂X线机平扫,将影像资料上传至临床图像显示系统(Qreads 5.10)。选取主胸弯顶椎为测量平面,测量顶椎椎体旋转角度(AVR),主动脉到椎体距离(a线),主动脉到左侧椎弓根置钉点距离(b线),主动脉到椎管垂直距离(c线),主动脉到椎弓根置钉点连线的垂直距离(d线),主动脉椎体角(AVA),左侧椎弓根置钉点和主动脉内侧切线与椎体中轴线平行线间的夹角(∠α),左侧椎弓根置钉点和主动脉中心点连线与椎体中轴线平行线间的夹角(∠β)。采用配对样本t检验比较2种体位下各参数变化,采用Pearson相关分析对数据进行相关性分析。结果俯卧位AVR、c线均大于仰卧位,差异均有统计学意义(P 0.05),平均差值分别为2.71°、2.24 mm。俯卧位与仰卧位AVA平均差值为4.45°,差异有统计学意义(P 0.05);俯卧位AVR、a线、b线、c线、d线、AVA、∠α、∠β与仰卧位相应指标呈正相关;俯卧位∠β与主胸弯Cobb角呈正相关,与俯卧位及仰卧位AVR均呈负相关;俯卧位d线与主胸弯Cobb角呈负相关,与俯卧位及仰卧位AVR呈正相关。结论相较于仰卧位,脊柱侧凸患者俯卧位时顶椎旋转度增大,主动脉到椎管的垂直距离增大,主动脉向椎体右前方移动。     

Hemodynamics during laparoscopy in the supine or prone position

During laparoscopy elevations in arterial pressure and a decrease in cardiac output have been reported. Laparoscopic surgery performed in the prone position may be advantageous for some surgical procedures, but the hemodynamic effects of pneumoperitoneum in this position have not been studied. We studied the effects of different levels of increased intraabdominal pressure on hemodynamics and oxygen transport in eight pigs in the prone and the supine position. Increases in intraabdominal pressure did not result in decreased cardiac output or in a reduction of oxygen transport and consumption in either position. These results suggest that laparoscopy in the prone position does not result in more severe hemodynamic depression than laparoscopy in the supine position.     

仰卧和俯卧位经皮肾镜碎石术在患者血气分析的对比研究

目的 探讨仰卧位和俯卧位经皮肾镜碎石术(PCNL)对患者血气分析指标的影响.方法 2012年1月～ 2014年1月本院110例经皮肾镜碎石术,分为仰卧位和俯卧位两组,每组55例,分别记录两种手术体位患者的术前、术中30min、手术结束各时间段血气分析的数据,比较两种不同体位上述数据的差异.结果 两组术中术后相比术前在PH值、剩余碱方面都有所下降,差异有统计学意义(P＜0.05),且俯卧位下降更明显;在血钠、血钾方面差异无统计学意义(P＞0.05).结论 仰卧位和俯卧位经皮肾镜碎石术两组对血气分析都各自有不同程度的影响,且仰卧位相比俯卧位经皮肾镜碎石术具有对血气分析影响更小、更轻,因此仰卧位经皮肾镜碎石术对年老体弱、肥胖、身体畸形体位搬动不便和有慢性心肺疾患的患者尤为适用,是一种安全和便利的治疗肾结石的微创手术方式.     

Topographic anatomy of the caliceal stem: the colonic risk

Body-section roentgenograms were taken of seventy five patients examined for non-urological complaints. These were studied and the axes of the ventral and dorsal calices were measure. The axis of the ventral calix passes through the left or right colon. The axis of the dorsal calix follows the avascular line and passes to the lateral border of the paravertebral muscles, avoiding the left and right colon. These anatomical data confirm that the dorsal calix is the route of choice in the percutaneous approach to the kidney.     

Evaluation of transesophageal atrial pacing in the prone and lateral positions

OBJECTIVE: To develop recommendations for positioning the second-generation pacing esophageal stethoscope for transesophageal atrial pacing in patients positioned prone (P), right lateral decubitus (RLD), and left lateral decubitus (LLD). DESIGN: Prospective; patients assigned consecutively. SETTING: Tertiary and university hospitals. PARTICIPANTS: Thirty (10 in each position group) adult patients undergoing surgery. INTERVENTIONS: The optimal depths of insertions (DOI) where pacing current threshold was minimal (THmin) were determined first when supine, then after positioning. MEASUREMENTS AND MAIN RESULTS: Transesophageal atrial pacing was successful in all patients supine and after positioning. The optimal DOI varied from 2 cm less deep to 4 cm deeper in positioned patients compared with supine patients. Patients positioned P required equal or up to 8 mA greater current outputs to achieve transesophageal atrial pacing; LLD and RLD patients may require up to 8 mA greater or lesser current compared with supine patients. CONCLUSION: Transesophageal atrial pacing can be used safely and effectively in patients positioned P, RLD, and LLD. Recommendations are presented for positioning the pacing esophageal stethoscope. Emphasis is given to using the lowest DOIs and smallest currents to reduce the chance of transesophageal ventricular pacing.     

Endoscopic combined intrarenal surgery in prone split-leg and inclined supine positions to treat renal cast and multiple calyx stones: An invited commentary

This Invited Commentary discusses the following article:Mulay A, Mane D, Mhaske S, Shah AS, Krishnappa D, Sabale V. Supine versus prone percutaneous nephrolithotomy for renal calculi: Our experience. Curr Urol 2022;16 (1):25-29. doi: 10.1097/CU9.0000000000000076.

Urolithiasis is a common disease encountered in urology. Its incidence is 0.1%-14.8% in Western countries and 5.94%-9.15% in China, with a significantly higher incidence in South China than in North China. In some areas of South China, the incidence of calculi exceeds 20%.^[1] Currently, percutaneous nephrolithotomy (PCNL) is the preferred treatment option for patients with multiple complex, renal cast, and multiple calyx stones.^[2] Complex multiple stones are associated with a lower stone clearance rate and a higher complication rate.^[3] Multichannel lithotripsy and endoscopic combined intrarenal surgery (ECIRS) in prone split-leg and inclined supine positions can improve the stone clearance rate.^[4] The 2016 American Urological Association guidelines established multi-channel PCNL as a safe and effective treatment for complex stones. In a previous study, the stone-free rate in a single operation was 79%, but the size and number of channels increased, followed by an increased risk of bleeding.^[5]In the article “Supine versus prone percutaneous nephrolithotomy for renal calculi—Our experience,” Mulay et al. evaluated the efficacy and safety of PCNL in modified supine and prone positions and showed that PCNL and ECIRS can be performed simultaneously in the supine position. In 1992, Ibarluzea et al. introduced ECIRS in the modified supine position.^[6] With the improvement and development of various urological surgical techniques and instruments, retrograde intrarenal surgery (RIRS) is no longer just an adjunctive or alternative surgery but an important part of clinical treatment. Better clinical outcomes and minimization of surgery-related complications can be achieved by combining RIRS with PCNL. A systematic review of 14 ECIRS cases showed that ECIRS had a stone-free rate of 61%-97%, a complication rate of 5.8%-42%, and a reduced risk of bleeding. Moreover, the bleeding risk was not correlated with the PCNL puncture channel size.^[7] Modified supine ECIRS has the following advantages over multichannel PCNL:

1. No position adjustment is required after anesthesia.
2. Direct vision puncture can be performed, and the puncture needle and dilator can enter the collecting system without being too deep under the direct vision of the transurethral ureteroscope, ensuring the safety and effectiveness of the puncture and reducing the incidence of complications when the channel is established.
3. The first choice for percutaneous renal puncture in ECIRS is the inferior calyx approach, and flexible ureteroscopy is performed to treat stones in the middle and upper calyces, which are relatively easy to access. Simultaneously, the advantages of flexible ureteroscopy for exploration include treating parallel calyx stones. For lower parallel calyx stones, the stone basket under the flexible scope can be used to move the stone to a position that can be treated with nephroscopy, after which the stone can be crushed and extracted.
4. Stone fragments entering the ureter can be treated without position adjustment, thereby reducing the rate of reoperation.
5. Combined PCNL and RIRS can treat ureteral and kidney stones simultaneously.
6. The stone clearance rate improves without increasing the risk of bleeding.
7. Combined with ureteral twisting and stenosis, it is difficult to insert the double J stent tube from the PCNL channel after lithotripsy. The double J stent tube can be placed retrogradely through the urethra using the ECIRS without position adjustment.

ECIRS can also be performed in the prone split-leg position, which has several advantages compared to the modified supine position as follows:

1. The prone split-leg position fully exposes the percutaneous renal puncture area of the affected kidney at the waist.
2. This position is simpler than the modified supine position and effectively reduces the workload of medical staff.
3. The peripheral organs, such as the intestines, are lowered by gravity, reducing the risk of organ damage.
4. The intrarenal perfusion effect is better in the prone position; therefore, the operative field of view is unaffected.
5. The modified supine position typically has a longer PCNL tract, particularly in patients with obesity, with decreased nephroscopic mobility and greater renal parenchymal mobility; thus, the bleeding risk is high, and extra-long devices should be provided.

However, the prone split-leg or inclined supine position is not significantly superior in terms of urological parameters, such as the stone clearance or complication rate.^[8]PCNL technology has evolved mainly owing to improvements in puncture technology, endoscopic instruments, lithotripsy devices, and drainage management. The introduction of the split-leg prone and improved supine positions is also part of the development. The development of ECIRS reflects the individualized management of patients with stones. ECIRS in split prone and modified supine positions is associated with a higher stone clearance rate, less blood loss, shorter operative time, and reduced perioperative complications when treating renal cast and multiple calyx stones. This is a new, safe, and effective procedure for PCNL.     

Continuously alternating prone and supine positioning in acute lung failure]

Acute respiratory failure is still one the main problems in surgical intensive care. Unknown pathophysiological mechanisms permit only symptomatic therapy. Today ventilatory strategies by using PEEP und IRV are established to improve gas exchange and FRC by recruiting collapsed alveoli, decreasing intrapulmonary shunting and returning V/Q matching to normal. Furthermore different studies have shown the effects of supine and lateral decubitus posture in patients with acute respiratory failure. There are only rare reports on using the prone position, which doesn't require two-lung ventilation in difference to lateral position. We have studied 16 patients with acute respiratory failure by using continuous changing between prone and supine position under mechanical ventilation. All were male, aged 41.3 years in the middle and showed an average "Injury Severity Score" of 30 (13-50). 15 were trauma patients with blunt chest trauma in 11 cases. We have used prone position on threatening or manifest ARDS. In all patients we observed an increment of PaO2 during prone position on to 48 mmHg so that FiO2 could be reduced on an average of 0.2 within the first 48 h since changing patient's position. Posture changing depends on blood gas analysis, specifically on decreasing PaO2 after previous increment. Patients remained in prone and supine position at a mean of 6.3 (4.5-20) h and posture changing was proceeded over a period of 15.4 (7-32) days. No problems recording to blood pressure or mechanical ventilation appeared during prone position. 11 of 16 patients survived (68.8%), 5 died of cardiac (2) and multi organic failure (3) in connection with sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Infundibulopelvic anatomy and clearance of inferior caliceal calculi with shock wave lithotripsy

PURPOSE: We evaluate the significance of inferior caliceal radiographic anatomy and determine its influence on successful fragmentation and clearance of inferior caliceal calculi with extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: Between November 1996 and February 1998, 88 patients and 90 renal units with single or multiple inferior caliceal calculi of all sizes and composition were treated with ESWL. The size, number and area of calculi, length and width of the stone bearing inferior calix and infundibulopelvic angle were determined on pretreatment excretory urography. The infundibulopelvic angle was measured by 2 methods using the angle between the inferior caliceal infundibular and ureteral axes (angle 1), and between the infundibular and ureteropelvic axes (angle 2). Cases with residual fragments not clearing within 6 months of satisfactory fragmentation after lithotripsy were considered failures. RESULTS: Overall stone clearance at 6 months was achieved in about 72% of the renal units. Infundibular length was 30 mm. or less in 77% of successful cases and in 64% of failures. Similarly, the smallest infundibular width of 5 mm. or more was found in 75% of successful cases compared to 41% of failures. Angle 1 of 35 degrees or more was observed in 73% of cases with compared to 18% without clearance. Angle 2 of 45 degrees or more was seen in 71% of successful cases compared to 9% of failures. The chances of a patient becoming stone-free with all favorable criteria of infundibular length 30 mm. or less, infundibular width 5 mm. or greater and infundibular ureteropelvic angle 45 degrees or greater was 100% (23 patients). CONCLUSIONS: Radiographic features of a stone bearing inferior calix and its relation to the renal pelvis can be easily measured on standard excretory urography. An infundibular width of 5 mm. or more and infundibulopelvic angle 1 of 35 degrees or more or angle 2 of 45 degrees or more were statistically significant factors of radiographic anatomy in stone clearance following ESWL. Inferior caliceal length was not statistically significant, although length of 30 mm. or less appeared to be more favorable for stone clearance. The ideal treatment of inferior caliceal calculi in patients with all 3 favorable criteria is ESWL.     

腰肋悬空位和俯卧位经皮肾镜碎石术对患者血流动力学影响的比较

目的探讨腰肋悬空位和俯卧位经皮肾镜碎石术对患者血流动力学的影响。方法 2010年1月～2011年1月我院100例经皮肾镜碎石术,随机分为腰肋悬空位和俯卧位两组,每组50例,分别记录两种手术体位患者的术前、改变体位后、术中30min、术毕各时间段患者血压、心率、呼吸、血氧饱和度的数据;统计并比较两种不同体位上述相关数据的差异。结果俯卧位组在改变体位后,其血压（收缩压/舒张压）相比术前血压基础值都呈明显下降趋势,而心率则无明显变化;腰肋悬空位组在改变体位后,其血压（收缩压/舒张压）相比术前血压基础值都呈下降趋势,而心率则无明显变化;在血流动力学方面,两组术中、术后相比术前在血压方面都有所下降,两组组内比较均有统计学意义（P〈0.05）;而两组间在血流动力学方面比较,俯卧位与腰肋悬空位组间比较,俯卧位对血压的影响相比仰卧位更明显（P〈0.05）。而两组在血氧饱和度、呼吸频率方面改变体位后与基础值相比两组均无明显变化,两组间和组内比较无统计学差异（P〈0.05）。结论腰肋悬空位经皮肾镜碎石术对血流动力学影响较俯卧位小,因此该术式对年老体衰、高危肥胖、身体畸形体位搬动不便和有慢性心肺疾患的患者尤为适用,是一种安全、有效、便利的治疗肾结石的微创方式。     

Computerized tomography imaging in adolescent idiopathic scoliosis: prone versus supine

Background

The aim of the present study was to assess the degree of apical vertebral rotation values in Adolescent Idiopathic Scoliosis (AIS) that were obtained on CT scans, and to analyze the influence of patient position (supine versus prone) on the degree of rotation.

Methods

The study included 50 apical vertebra rotation measurements of 34 patients with Type 1A and Type 3C curvature according to the Lenke classification. CT imaging was applied to the patients in supine and prone positions to measure the apical vertebral rotation (AVR). The average AVR angles were measured using the Aaro–Dahlborn method and the results were compared.

Results

No significant differences were found between the vertebral rotation measured in the prone and supine positions for the Lenke 1A subgroup and the Lenke 3C thoracic group (p = 0.848; p = 0.659, respectively). In the Lenke 3C lumbar group, however, the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position (difference ?1.40° ± 1.79°, p = 0.007).

Conclusion

The assessment of the apical vertebra rotation is crucial in AIS. Even though the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position, CT imaging in a prone position could not be considered clinically more relevant than the CT images in a supine position as there was less than 3° difference.

     

Kidney displacement in complete supine PCNL is lower than prone PCNL

To compare the amount of the kidney displacement in the complete supine percutaneous nephrolithotripsy (PCNL) to the prone PCNL during getting renal access. Thirty-three patients were randomly divided into two groups. The patients in group A were placed in the complete supine position and the patients in group B in the prone position. Amounts of the kidney displacement in three states and other data were analyzed. The mean amount of the kidney displacement in the complete supine PCNL was 10.1 ± 7.9 mm in stage 1, 10.7 ± 8.28 mm in stage 2 and 12.2 ± 10.4 mm in stage 3. The mean amount of the kidney displacement in prone PCNL was 16.6 ± 5.8 mm in stage 1, 16.2 ± 6.3 mm in stage 2 and 17.6 ± 6.7 mm in stage 3. In stages 1 and 2, a significant difference between the two groups derived from the mean amount of the kidney displacement, but the difference was not statistically significant in stage 3. Adjusted for age, gender, BMI, stone burden and position of PCNL, prone position was a predictor caused significantly more displacement in all three stages. Among other predictors, only BMI had a significant effect on the amount of the kidney displacement (in stages 2 and 3). Performing PCNL in the complete supine position is safe and effective and leads to less kidney displacement during getting renal access and therefore, it may be considered in most patients requiring PCNL.     

超声引导下仰卧位和俯卧位两种腘静脉穿刺方法的比较

背景与目的 超声引导下腘静脉穿刺是下肢静脉腔内手术的常用入路之一,目前多是采用俯卧位,但长时间的俯卧位手术会让患者感觉不适。因此,本研究探讨采用仰卧位在超声引导下穿刺腘静脉的可行性,并比较采取仰卧位和俯卧位两种方法的优劣。方法 将髂静脉狭窄性疾病患者随机分成两组,分别在仰卧位和俯卧位下使用超声引导进行腘静脉穿刺,分析术中穿刺所用时间、患者不适程度的视觉模拟评分（VAS）等指标以及术后并发症发生情况。结果 共纳入27例患者,其中仰卧位组14例（16条肢体）,俯卧位组13例（16条肢体）。两组患者的基线资料及病变静脉处理方法差异均无统计学意义（均P>0.05）。仰卧位穿刺腘静脉所用的操作时间与俯卧位穿刺腘静脉所用的操作时间差异无统计学意义［3.7（3.4~6.2）min vs. 4.2（3.5~4.4）min,P>0.05］。仰卧位组的VAS评分明显低于俯卧位组［2.0（1.0~2.8）vs. 6.0（4.0~8.0）,P<0.01］。仰卧位组有1例术后腘动脉分支出血,经过超声引导下压迫动脉破口后成功治愈。结论 与俯卧位穿刺腘静脉相比,仰卧位穿刺腘静脉不会延长手术时间,但明显减少了患者的不适感,因此,推荐临床使用。     

Efficacy of supine versus prone biliary lithotripsy: an in vitro study

Clinical extracorporeal shock wave lithotripsy (ESWL) results have shown that the smaller the gallstone fragments following ESWL, the faster the patient will become stone-free. At ESWL, an attempt is made to produce sand-like fragments that will easily pass through the cystic and common bile ducts. Sixteen pairs of gallstones of equal shape, size, and composition were harvested from cholecystectomy specimens and then fragmented on the Dornier MPL-9000 lithotripter (Dornier Medical Systems, Inc.), individually, in a phantom oriented to duplicate either supine or prone patient positions. The number and size of remaining fragments were compared following the supine versus prone treatments. The 32 stones, ranging from 5-15 mm in diameter, received 1,500 shock waves at 21 kV. Fragments with a maximal diameter of greater than or equal to 4 mm were measured and counted after 750 and 1,500 shock waves. Fragments greater than or equal to 4 mm were found in four out of 16 stones treated supine (25%) and 16 out of 16 stones treated prone (100%). The largest residual fragment regardless of size for each stone pair occurred in the prone group in 14 out of 16 cases (88%). Biliary lithotripsy performed with supine positioning results in more efficacious gallstone fragmentation in this in vitro model; these findings suggest that supine positioning for patients could improve fragmentation and treatment success.     

Erect and supine radiographs to assess effectiveness of SWL for stones in a caliceal diverticulum or dilated calix

BACKGROUND AND PURPOSE: There are patients who have been treated with shockwave lithotripsy (SWL) for stones in a caliceal diverticulum (CD) or a dilated calix in whom the degree of fragmentation is difficult to assess. The aim of this study was to see if adequate fragmentation could be confirmed by the demonstration of layering of fine fragments on an erect radiograph. PATIENTS AND METHODS: Over a period of 9 months, 13 patients with stones in a CD or a dilated calix with a stenosed infundibulum were studied 2 weeks after SWL with erect and supine radiographs. RESULTS: One of eight patients with a CD cleared all fragments. Two patients showed no change in the appearance of the stone on either the supine or the erect film, and of the remaining five patients, three demonstrated layering of sand at the base of the CD. Five patients with a dilated calix and a narrow infundibulum were also studied: two of these patients became stone free, two demonstrated complete fragmentation with layering of the sand, and in one patient, a 4-mm fragment, hidden within the sand, was revealed only on the erect film. CONCLUSION: There are patients who have been treated with SWL for stones in a CD or a dilated calix in whom adequate fragmentation is difficult to demonstrate. An erect radiograph in these patients may demonstrate layering of the fragments to confirm fragmentation and obviate repeat SWL.