Patients
From September 2017 to September 2019, 80 patients diagnosed with staghorn renal stones by ultrasound (US), plain film of kidney-ureter-bladder (KUB) or computed tomography (CT) at the Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (Shanghai, China) were retrospectively analyzed. The Ethics Committee of Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine has approved the study (reference number: XHEC-D-2020-101), and verbal consents were obtained from all the participants because all the information was required from historic electronic records. The inclusion criteria for this study were: i) Age, ༞12 and ≤ 75 years; ii) staghorn renal stones with refractory infections, or without infections; iii) PCNL assisted by the fifth-generation EMS lithotripsy; and iv) one-phase treatment. The exclusion criteria were: i) Patients with other complex renal stones, ureteral stones, bladder stones, renal tumor, renal tuberculosis, acute and chronic nephritis, or nephrotic syndrome; ii) patients with severe lung, heart, urinary system abnormalities, or blood system diseases; and iii) patients with incomplete clinical data, or poor compliance, or those who interrupted treatment.
Patients with staghorn renal stones were divided into A group (n = 48, with refractory infections) and B group (n = 32, without infections) according to whether they were complicated with refractory infections. In A group, there were 23 males (47.92%) and 25 females (52.08%), and an average age of 53.54 ± 9.50 years (age range, 31–71 years). The average value of body mass index (BMI) was 24.16 ± 3.15 kg/m2 (BMI range, 18.08–32.05 kg/m2). There were 11 patients (22.92%) with hypertension and six patients (12.50%) with diabetes. The surface area (SA) of stones ranged from 91.61 to 4541.78 mm2, with an average of 733.67 ± 760.25 mm2. There were 28 stones (58.33%) on the left side and 20 stones (41.67%) on the right side. The CT value of stones ranged from 336.90 to 1372.30 Hu, and an average of 957.87 ± 269.00 Hu. Before operation, there were 47 cases (97.92%) with white blood cell (WBC) count (≤ 10 × 109/L), and only 1 case (2.08%) with WBC count (༞10 × 109/L). There were ten patients (20.83%) with preoperative C-reactive protein (CRP;≥8 mg/L). The range of preoperative hemoglobin (Hb) was 85.00-177.00 g/L, with an average value of 132.42 ± 18.70 g/L. Moreover, there were 25 patients (52.08%) with hydronephrosis and seven patients (14.58%) with renal insufficiency.
In B group, there were 22 males (68.75%) and ten females (31.25%), with an average age of 54.19 ± 14.61 years (age range, 14–73 years). The range of BMI was 16.98–31.28 kg/m2, and an average of 23.58 ± 3.15 kg/m2. Among them, there were 12 cases (37.50%) of hypertension and 3 cases (9.38%) of diabetes. The patients had staghorn renal stones of 134.77-2718.15 mm2 in SA and an average of 613.74 ± 493.79 mm2, with 11 stones (34.38%) on the left side, and 21 stones (65.63%) on the right side. The CT value of stones ranged from 374.10 to 1416.40 Hu, with an average of 883.77 ± 286.98 Hu. Before operation, there were 31 patients (96.88%) with WBC count (≤ 10 × 109/L), and only 1 case (3.13%) with WBC count (༞10 × 109/L). There was one patient (3.13%) with preoperative CRP (≥ 8 mg/L). The preoperative Hb ranged from 108.00 to 166.00 g/L, with an average of 136.56 ± 17.51 g/L. In addition, there were 16 cases (50.00%) of hydronephrosis and 6 cases (18.75%) of renal insufficiency. Before operation, there was statistical significance in the location of stones between the two groups (P = 0.036), while there were no statistical significances in other general clinical data between the two groups (P༞0.05), as shown in Table 1.
Table 1
Comparison of preoperative general clinical data between A group and B group
Variables | A group (n = 48) | B group (n = 32) | P value |
Gender | | | |
Male | 23 (47.92%) | 22 (68.75%) | 0.066 |
Female | 25 (52.08%) | 10 (31.25%) | |
Age, years | 53.54 ± 9.50 | 54.19 ± 14.61 | 0.811 |
BMI, kg/m2 | 24.16 ± 3.15 | 23.58 ± 3.15 | 0.423 |
Hypertension | 11 (22.92%) | 12 (37.50%) | 0.158 |
Diabetes | 6 (12.50%) | 3 (9.38%) | 0.942 |
Location of stones | | | |
Left | 28 (58.33%) | 11 (34.38%) | 0.036 |
Right | 20 (41.67%) | 21 (65.62%) | |
SA of stones, mm2 | 733.67 ± 760.25 | 613.74 ± 493.79 | 0.433 |
CT value of stones, Hu | 957.87 ± 269.00 | 883.77 ± 286.98 | 0.243 |
WBC count (༞10 × 109/L) | 1 (2.08%) | 1 (3.13%) | 1.000 |
CRP (≥ 8 mg/L) | 10 (20.83%) | 1 (3.13%) | 0.055 |
Hb, g/L | 132.42 ± 18.70 | 136.56 ± 17.51 | 0.322 |
Hydronephrosis | 25 (52.08%) | 16 (50.00%) | 0.855 |
Renal insufficiency | 7 (14.58%) | 6 (18.75%) | 0.621 |
BMI, Body mass index; SA, Surface area; CT, Computed tomography; WBC, White blood cell; CRP, C-reactive protein; Hb, Hemoglobin. |
Surgical procedures
After general anesthesia, patients with staghorn renal stones were in the position of lithotomy. The Wolf F8/9.8 rigid ureteroscope (Richard Wolf GmbH, Knittlingen, Germany) was retrogradely inserted into the F5 ureteral catheter (Shanghai Shangyi Kangge Medical Equipment Co., Ltd, Shanghai, China) to renal pelvis or upper ureter of the affected side, and was fixed together with the F18 Bard urinary catheter. Subsequently, change the patients to a prone position and raise the patients' waist. The percutaneous puncture sites of patients with staghorn renal stones were guided by US in vitro. The method of puncture adopted a combination of US in-plane and out-of-plane (as well as the head and sides of the US probe). After the puncture needle entered the renal calices on the dorsal side, a black loach guide wire (Cook Medical, Inc., Bloomington, IN, USA) was inserted. F8 fascial dilator was placed along the black loach guide wire and pre-expanded, followed by the balloon dilator. Infuse normal saline into a pressure pump. When the pressure reached 25 Kpa, the balloon was expanded to F24, and the F24 sheath was pushed along the balloon dilator (C. R. Bard, Inc., Covington, Georgia, USA) to establish the F24 skin renal channel. After establishing the F24 skin renal channel, the operator placed a nephroscope to observe the condition of each patient's renal calves and staghorn renal stones, and then crushed the stones with the fifth-generation EMS Swiss LthoClast®LCM21. For staghorn renal stones with refractory infections, the surgeon adopted the negative pressure suction of the fifth-generation EMS lithotripsy to clear the purulent fluid in the affected kidney. Under the condition of continuous low pressure, stones in the renal pelvis and the renal calices were quickly crushed by US lithotripsy and sucked out by negative pressure suction. After the stones were cleared, the F6 D-J tube (Cook Medical, Inc., Limerick, Ireland) was inserted antegrade through the nephroscope, and the F22 silicone drainage tube was inserted. If there was no active bleeding, the nephrostomy tube was opened; If there was active bleeding, the nephrostomy tube was clamped for 1 to 3 hours.
After PCNL, the patients took antibiotics for prophylactic anti-infection treatment. KUB was reexamined 2-3 days after operation in order to understand the position of F6 D-J tube and the residual situation of stones. If the stones were not removed during operation, extracorporeal shock wave lithotripsy (ESWL), flexible ureteroscopy lithotripsy (FURL) or PCNL of the two-phase were performed; If the stones were removed during operation, the urinary catheter was removed on the 5th day after operation, and the F22 nephrostomy tube was clamped for 1 day. If there was no swelling or fever, the nephrostomy tube was removed on the 6th day after operation. After 4-6 weeks, KUB or CT were reexamined in the outpatient department to understand the stones discharge and remove the F6 D-J tube.
Observation indexes and detection methods
The differences on gender, age, BMI, hypertension, diabetes, location of stones, SA of stones, CT value of stones, preoperative WBC count, preoperative CRP, preoperative Hb, hydronephrosis, renal dysfunction, operation time, hospitalization time, WBC count on the first day after operation, CRP on the first day after operation, procalcitonin (PCT) on the first day after operation, postoperative Hb, SFR, complications including fever (≥38.5 °C), using analgesics after operation, UTI, systemic inflammatory response syndrome (SIRS), blood transfusion and collecting system perforation between the two groups were compared. At present, there is still a lack of unified standards for refractory infection. Therefore, we defined refractory infection in this study as patients with staghorn renal stones before operation who still had UTI, or urine culture was still positive after treatment with sensitive antibiotics, or purulent urine or infectious flocculent was still observed in the renal pelvis and renal calices during operation. Operation time was from the establishment of the channel to the placement of nephrostomy tube. Hospitalization time was from the first day after operation to the day of discharge. SFR referred to the fragments of retained stone with a size of <0.40 cm or no retained stone found and free from any clinical symptoms under CT, KUB or US examination within 3 months after operation. Modified Clavien-Dindo grading system was used to grade postoperative complications.
Statistical analysis
The statistical analysis of all the clinical data was performed with SPSS 25.0 software (IBM SPSS, Armonk, NY, USA). Measurement data were expressed as the mean ± standard deviation, and comparison between the groups was analyzed using the t-test. Qualitative data were expressed as number (percentage), and comparison between the groups was made applying the χ2 test. P<0.05 was deemed to be statistically significant.