I. Expectant therapy
Some patients with complicated renal stones often have insignificant symptoms or present only with recurrent urinary tract infections, which were often treated symptomatically in the past due to mild symptoms and lack of awareness of their risks.
However, a growing number of studies have shown that conservative treatment increases the complication rate and mortality in patients because obstruction and infection caused by stones can lead to destruction of renal function. The risk of chronic renal failure was 36% higher in patients treated conservatively than in the surgical group, with correspondingly higher rates of complications and mortality.
Teichman et al. retrospectively analyzed a mean follow-up of 7.7 years in 177 patients with antler-shaped kidney stones, in which the rate of deterioration of renal function was 28% and none of the patients with complete stone clearance died of kidney-related disease, whereas in patients who refused treatment, the mortality rate was 67%. Thus, they concluded that untreated complex kidney stones almost always impair renal function and can lead to end-stage renal failure and/or sepsis.
In a follow-up of 70 patients with kidney stones with chronic renal insufficiency, Singh et al. found a mean decrease in blood creatinine of 135.2 μmol/L (32%) and a mean improvement in renal function of 20.7% 9 months after removal of stones by surgical treatment, and 41 patients were spared from continued dialysis treatment.Paryani and Ather compared blood creatinine values before and after surgery in 43 patients with kidney stones. It was found that after surgical treatment, the blood creatinine decreased from a mean of 555 mmol/L before surgery to a mean of 193 mmol/L after surgery, and the patients’ renal function was significantly improved.
Therefore, patients with complex renal stones, except those with short life expectancy, poor general condition, or those who cannot tolerate anesthesia or surgery, should be treated aggressively to remove the stones and protect the residual renal function.
Extracorporeal shock wave lithotripsy (ESWL)
Since the first successful treatment of renal stones with DornierHM1 extracorporeal shock wave lithotripter by Chaussy et al. in Germany in 1980, ESWL technology has made rapid development, which is epoch-making in the treatment of urinary stones, but attention should be paid to the selection of cases in the application of ESWL for the treatment of complicated renal stones. Koko et al. performed a study on 61 cases of deerstalker-shaped renal stones treated with ESWL alone. Koko et al. conducted a 41-month follow-up of 61 patients with antler-shaped kidney stones treated with ESWL alone and found that other adjunctive modalities were needed 162 times during the treatment of all patients to manage complications of ESWL (e.g., “stone streets”).
The stone-free rate after 3 months of treatment was only 18.0%, and although the rate increased to 63.9% at the end of the treatment cycle (41 months), the authors concluded that ESWL alone is not sufficient for the treatment of deerstalker kidney stones because of its high complication rate, long treatment time and hospital stay. The American Urological Association (AUA) also concluded that ESWL alone is very limited in the treatment of complex renal stones, with a mean stone free rate of 54.0% (45.0% to 64.0%).
The stone removal rate of ESWL is related to the anatomy of the kidney, the size, composition and location of the stone. the stone free rate of ESWL for partial deerstalker stones is significantly higher than that for complete deerstalker stones, while the number of treatments and complications are significantly reduced; the stone free rate of ESWL alone for hard partial and complete deerstalker stones (e.g. cystine stones) is very low and therefore should not be performed.
ESWL alone should only be considered for partial deerstalker-shaped kidney stones located in the renal pelvis and upper and middle calyces if the patient has a contraindication to surgery and the surface area of the stone is small (≤500 mm2), and the insertion of a ureteral double J tube or placement of a nephrostomy tube is recommended before lithotripsy to prevent stone street formation after ESWL.
Compared with other treatment methods, ESWL has relatively mild complications, mainly subperitoneal or retroperitoneal hemorrhage and stone street formation. The occurrence of complications can be reduced by appropriately reducing the shock wave energy, increasing the number of shocks and inserting double J-tube before surgery.
Percutaneous nephrolithotomy (PNL)
PNL is a technique to remove stones by establishing a percutaneous nephrostomy channel under direct nephroscopic view using a lithotripter and stone extraction instruments. PNL can be used for the treatment of almost all complex renal stones (including cystine stones) and stones with coexisting pelvic-ureteral junction obstruction or diverticula.
PNL has the highest mean stone-free rate (78.0%, 74.0% to 83.0%) among the various methods for the treatment of complex renal stones. Especially with the widespread use of flexible nephrolithoscopy, the availability of better stone extraction forceps and lithotripsy baskets, and the promotion of holmium laser and ultrasound/pneumatic ballistic lithotripsy, the stone removal rate has been further improved, the number of percutaneous puncture channels has been reduced, and the risk of the procedure has been reduced. Currently, PNL-based endoluminal techniques have become the basic means of treating complex renal stones.
Although the establishment of multiple percutaneous renal channels can improve stone clearance, it also increases the damage, leading to the destruction of more renal units and reducing the renal reserve, so the ideal approach is to establish a single percutaneous renal channel that can access most or all of the collecting system.
Netto et al. compared the effectiveness and complication rates of supracostal and infrarenal access for deerstalker kidney stones and found that the stone free and complication rates were 87.5% and 25.0%, respectively, for supracostal access and 80.0% and 21.4%, respectively, for infrarenal access. They concluded that although the complications of the supracostal channel were more but still within the acceptable range, the stone clearance rate after treatment was higher and it could be applied optionally in certain patients with stones (especially those with stones located in the upper group of calyces).
In 45 patients with antler-shaped stones (stones ≥5 cm in diameter), Wong and Leveillee established only one suprarenal pole channel with a soft nephroscope and holmium laser lithotripsy and achieved a 95% stone clearance rate after an average of 1.6 courses of treatment. The success rate of single-channel flexible nephroscopy combined with holmium laser for the treatment of complex renal stones was over 90.0%, which significantly reduced the complication rate without reducing the stone free rate.
The main complications of PNL are bleeding and damage to the perirenal organs. In addition, there are infections, sepsis, arteriovenous fistulas, and perirenal hematomas. Supracostal access may also cause pneumothorax and pleural effusion. The incidence of complications is related to the number of percutaneous renal channels; the more the number of channels, the higher the incidence of complications.
IV. Combined treatment with PNL and ESWL
The combined application of PNL and ESWL is one of the main methods for the treatment of complicated renal calculi. The combination of ESWL and PNL was recommended by AUA as early as 1994 for the treatment of larger size of deerstalker-shaped kidney stones. Compared with PNL alone, the combination treatment reduces the number of percutaneous renal channels, thus helping to reduce the incidence of complications such as bleeding, urinary extravasation and sepsis; compared with EWSL alone, the combination treatment reduces the applied dose of ESWL, thus mitigating the possible harm to the organism caused by high-dose shock waves.
There are two types of combination therapy, one is ESWL followed by PNL, and the other is PNL followed by ESWL to crush stones in hard-to-reach areas by nephroscopy, and finally PNL to remove stone fragments. The stone free rate of combined treatment with PNL + ESWL + PNL (“sandwich” therapy) was significantly higher than that of ESWL + PNL + ESWL, but the average stone free rate of combined treatment (66.0%, 60.0%-72.0%) was lower than that of PNL alone (78.0%).
The main role of the second PNL is to remove stone fragments as soon as possible to shorten the time of stone removal and reduce the chance of urinary tract infection and stone recurrence, which is therefore very important. The average rate of stone removal using combined PNL+ESWL+PNL was 67.8%-90.5%, with an average of 80.8%.
Currently, there are different opinions on the timing of ESWL after PNL, but there is no significant difference in the efficacy of various methods, and it is generally considered more appropriate to perform ESWL 1 to 2 weeks after PNL. In recent years, due to the application of flexible nephroscopy, the use of ESWL after PNL has a decreasing trend.
V. Retrograde ureteroscopic lithotripsy
Retrograde ureteroscopy for the treatment of complex renal calculi is based on flexible ureteroscopy, and its damage is between ESWL and PNL. The use of bendable flexible ureteroscope can reach the areas that are not easily reached by rigid ureteroscope due to the angle, but the existence of the angle of the inferior pelvic calyx makes it difficult for the flexible ureteroscope to reach part of the inferior calyx.
In the choice of laser conduction fiber, clinical use of 200 μm laser conduction fiber is mostly used because as the laser fiber thickens, it will inevitably lead to increased stiffness, which will reduce the bendability of the ureteral flexible ureteroscope and affect the free steering of the end of the ureteroscope, especially the activity in the infrarenal calyces will be greatly restricted.
Due to the limitation of fiber optics, the operation time of ureteroscopy alone for the treatment of complex renal stones is long, so it is mostly used as an adjunct to other treatment methods. mugiya et al. used ureteroscopy combined with ESWL for the treatment of deerstalker stones, and the results showed that the clearance rate of complete deerstalker stones was 61.0% in 13 cases and 80.0% in 10 cases with partial deerstalker stones. complications include urinary tract injury and infection The complications included urinary tract injury and infection.
Therefore, they concluded that retrograde ureteroscopy combined with PNL can help to reduce the number of channels compared with multi-channel PNL in the treatment of complex renal stones. kidney stones helped to reduce the number of channels and decreased the surgical complications, but did not decrease the stone removal rate.
VI. Open surgery or laparoscopic stone extraction
Because PNL, ESWL and other techniques are less invasive and can achieve more satisfactory results, they have gradually replaced open surgery as the preferred method for deerstalker stones, and the proportion of open surgery in some European and American countries is only about 1.0% to 5.4%. However, when the stone size is large and accompanied by moderate to severe pelvic calyces dilatation, PNL often requires other adjuvant treatments, and the hospital stay is long and the treatment cost is high, and the stone residual rate can be as high as 50.0% to 75.0%.
When complex renal stones are combined with intrarenal anatomical abnormalities and simultaneous renal reconstruction is required, open surgery should be the first choice. In open surgery, combined with endoscopic techniques to assist in stone extraction, bleeding can be reduced, operating time shortened, and stone removal rate improved. Chen Shiwei et al. applied the lumpectomy technique in open surgery to treat 38 cases of complicated renal stones, 34 cases had the stones removed in 1 operation, 4 cases had residual stones visible on X-ray, but only 2 of them needed treatment, and these 2 cases were cured by ESWL 1 to 2 months after surgery.
The main modalities of open surgery include enlarged pelvic dissection for stone extraction, combined pelvic parenchymal dissection for stone extraction, non-atrophic parenchymal dissection for stone extraction, multiple radial parenchymal dissection for stone extraction, partial nephrectomy and nephrectomy. With the advancement of laparoscopic technology, most of the cases requiring open surgery can be done laparoscopically, which helps to reduce the surgical trauma.
However, it should be noted that all kinds of parenchymal lithotomy operations inevitably lead to different degrees of postoperative impairment of kidney function (average decrease of 2.0%-8.0%), and even for non-atrophic parenchymal lithotomy, 30.0%-50.0% of patients still have postoperative renal hypofunction; the average lithotripsy-free rate of open surgery is only 71.0% (56.0%-84.0%), and the residual stone rate is still 71.0% (56.0%-84.0%). The average stone free rate of open surgery is only 71.0% (56.0%-84.0%), the stone residual rate is still as high as 15.0%-20.0%, and 30.0% of patients will have stone recurrence in 6 years after surgery. Therefore, the indications for open surgery should be strictly grasped.
Lithotripsy treatment
Lithotripsy is the chemical dissolution of stones or stone fragments to achieve complete stone removal, and can be used as an adjunctive treatment after ESWL, PNL, ureteroscopic lithotripsy, laparoscopic or open surgical stone extraction. At least two nephrostomy channels should be established for percutaneous chemical lithotripsy to avoid or reduce the side effects caused by the flow of lithotripsy fluid into the bladder and increased pressure in the kidney during perfusion. Experimental and clinical evidence shows that lithotripsy is effective for uric acid, phosphate and cystine stones, but it is not yet effective for calcium oxalate stones, which account for the majority of the urinary system, and is therefore not commonly performed in clinical practice.
VIII. Conclusion
In conclusion, in order to avoid damage to renal function, complex stones need to be treated promptly, and the specific treatment method should be selected according to the experience of the operator, the condition of the stone, and the requirements of the patient in order to maximize the stone removal rate and reduce surgical complications.