Table 4.

Criteria of postoperative complications after endoscopic surgery for nephrolithiasis

Grade	Cases
I	Hematuria through the nephrostomic tube or during self-urination that requires additional infusion therapy (more than 1 liter) and/or the use of diuretics;
	Fever above 38°C that remains elevated for less than 24 h and that requires the use of antipyretics or another therapy;
	Loss of the nephrostomic tube, not due to any intervention but requiring further observation;
	Urine leakage around the tube up to 48 h, with adequate functioning of the drainage;
	Transient elevation of the serum creatinine.
II	Infectious and inflammatory processes in the urinary tract that require additional antibiotic therapy (other than prophylactic) (acute pyelonephritis, acute prostatitis, acute urethritis, or acute cystitis), including when infusion-detoxification therapy prolongs the hospital stay of the patient;
	The need for analgesics within 48 hours of the operation or later, in connection with a previous intervention;
	Inadequate drainage of the kidney cavities that can be eliminated without further intervention but requires extra care and drugs other than those included in grade I;
	Urine leakage around the tube that lasts longer than 48 h and can be eliminated without further intervention but requires additional follow-up and the use of drugs beyond those included in grade I;
	The absence of a ureteral passage, leading to prolonged nephrostomy drainage in the kidney and the need for additional therapy;
	Any additional drug therapy that results in an exacerbation of the chronic comorbidities or transferred anesthesia (pneumonia, pleuritis, chronic bronchitis, repeated vomiting, prolonged headache, etc.);
	The treatment of wound infections (a rare occurrence after endoscopic interventions); Parenteral nutrition.
IIIa	Parenchymal bleeding combined with tamponade of the PCS* or the bladder, leading to the removal of blood clots (without general anesthesia);
	Replacement of the nephrostomic drainage, regardless of the cause (inadequate drainage of the cavities of the kidneys, loss of drainage, urine leakage around the tube, or a urinoma);
	Implementation of therapeutic and diagnostic FNAB** of the kidney[15,16] (e.g., a patient with acute pyelonephritis is categorized as grade II, but if he underwent a FNAB, the patient qualifies for IIIa);
	Installation of a ureteral stent (due to prolonged swelling of the mucous ureter because of damage to the pelvis and UPJ***);
	Setting a double-J stent due to getting wet with urine;
	Puncture of the pleural cavity with or without draining (caused by pneumothorax, hemothorax, or hydrothorax);
	X-ray radiological interventions (except routine antegrade pyeloureterography before removing the drainage);
	Obstruction and renal colic due to blood clots;
	Blood transfusions (?).
IIIb	PC nephrostomy or renephrostomy (drainage loss, bleeding, or the development of a urinoma);
	Ureteroscopy;
	Nephroscopy;
	Open intervention (due to a postoperative ureteral stricture or parenchymal bleeding);
	Arteriovenous fistula;
	Perirenal abscesses;
	Any other intervention under general anesthesia;
	Clinically significant residual stones after surgery for simple stones and additional interventions (?).
IVa	Dysfunction of one organ that developed after the intervention (kidney, lungs, liver, heart (heart attack), CNS**** (stroke)) that requires treatment in the intensive care unit;
	Monitoring during the postoperative period due to damage to a neighboring organ;
	Nephrectomy;
	Hemodialysis due to newly acquired renal failure;
	Urosepsis: severe sepsis (?).
IVb	Urosepsis: septic shock and refractory shock syndrome (multiorgan dysfunction) (?).
V	Death of the patient.
	Chronic renal failure during the intermittent phase. During the postoperative period: a forced session or sessions of hemodialysis (grade IIIa).

^*PCS: Pyelocaliceal system;

^**FNAB: Fine-needle aspiration biopsy^[15,16];

^***UPJ: Ureteropelvic junction;

^****CNS: Central nervous system; (?): interpretation provided in the discussion