Urinary lithiasis: evaluation of the use of laser vs. Pneumatic ureteral lithotripsy

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.


INTRODUCTION
Urinary lithiasis is a frequent pathology, which makes it noteworthy among pathologies of the uri-nary tract.Its diagnosis and treatment have changed with the incorporation of new technologies to extract stones via the urinary route.These changes have had a great impact on the cost of treatment, and the procedures need to be evaluated regarding their effectiveness and risks.
Procedure indication is based on the confirmation of the stone through exams that indicate precisely its size, location, and density, essential information to determine the type of technology to be used: the type of lithotritor [extracorporeal (EC) or intracorporeal (IC)] and the type of energy (ballistic/pneumatic (EC); ultrasound (US); Electro-hydraulic (EH) or laser (L).
The goal of this evaluation is to define the role of the use of laser power in comparison to the conventional method(s) for treating patients with an indication of fragmentation of urinary calculi through ureterolithotripsy.

COMPLICATIONS
Regarding the outcome of complications, we included eight studies 1-7.9 for analysis, totaling 1,457 patients (720 laser and 737 pneumatic).The analysis revealed a lower rate of complication risk with patients undergoing laser treatment: an increase of 10% (NNT: 10), ranging from 5% to 15%.Heterogeneity of <50%.

PROCEDURE TIME
Regarding the outcome of procedure time, we included five studies 1,4,5,7,9 for analysis, totaling 1,402 patients (704 laser and 698 pneumatic).The analysis showed no difference regarding the procedure time between the two modalities of treatment -heterogeneity of≥ 50%.
In the analysis of the outcomes of therapeutic success, stone free rate, and complications there was no bias of inconsistency (heterogeneity <50%).However, in the analysis of the outcomes of need for ureteral stent and procedure time, the heterogeneity was ≥50%.

SUMMARY OF EVIDENCE -WEAK
In patients with urinary lithiasis and stones <20 mm affecting the ureter.
There is no difference in the procedure time and the need for ureteral stent between the two types of treatment (laser and pneumatic ureterolithotripsy).
The laser treatment offers increased rates of therapeutic success and stone free rate outcomes and reduces the risk of complications when compared with pneumatic ureterolithotripsy.

Clinical question
In the treatment of urinary lithiasis by ureterolithotripsy, is the use of a laser energy source superior to the conventional one (pneumatic)?

Relevance -clinical importance
This guideline was prepared by means of a clinically relevant question in order to gather information in medicine to standardize approaches and assist in decision-making.

Reliability -Internal validity
The selection of the studies and the evaluation of the titles and abstracts obtained from the search strategy in the databases consulted were independently and blindly conducted in total accordance with the inclusion and exclusion criteria.Finally, studies with potential relevance were separated.When the title and the summary were not enlightening, we sought for the full article.Only studies with texts available in its entirety were considered for critical evaluation.

Results application -External validity
The level of scientific evidence was classified by type of study, according to Oxford 10 (Table 1).The selected evidence was defined as a randomized controlled clinical trial (RCT) and submitted to an appropriate critical evaluation checklist (Table 2).
The critical evaluation of RCTs allows to classify them according to the Jadad score 11 , considering Jadad trials < three (3) as inconsistent (grade B) and those with score ≥ three (3), consistent (grade A), and according to the Grade 13 score (strong or moderate evidence).
When the evidence selected was defined as a comparative study (observational cohorts, or non-randomized clinical trial), it was subjected to an adequate critical assessment checklist (Table 3), allowing for the classification of the study, according to the NEWCASTLE OTTAWA SCALE 12 , which considered consistent cohort studies with scores ≥ 6, and inconsistent <6.

Method of extraction and result analysis
For results with available evidence, the population, intervention, outcomes, presence or absence of benefits and/or harmful effects, and controversy will be specifically defined whenever possible.
The results will be presented, preferably in absolute data, absolute risk, number needed to treat (NNT) or number needed to harm (NNH) and, eventually, in mean and standard deviation values (Table 4).None of the studies is blinded, 30% did not properly randomize, 50% did not have blindfolded allocation, did not calculate the sample, and Jadad was inconsistent (<3), in 80% the analysis was not by intention to treat, and 10% had ≥20% losses, thus, by these criteria, with high overall risk of bias.

TABLE 1 .
GRADES FOR RECOMMENDATION AND LEVELS OF EVIDENCEA: Experimental or observational studies of higher consistency.B: Experimental or observational studies of lower consistency.

TABLE 2 .
PROCESS FOR CRITICAL EVALUATION OF RANDOMIZED CONTROLLED TRIALS

TABLE 3 .
PROCESS FOR CRITICAL EVALUATION OF COHORT STUDIES

TABLE 4 .
SPREADSHEET USED FOR DESCRIBING AND PRESENTING THE RESULTS OF EACH STUDY

TABLE 5 .
CHARACTERISTICS OF STUDIES INCLUDED RESULTS1.FLOWCHART OF STUDIES RETRIEVED AND SELECTED (PRISMA 2009) FIGURE 1. RISK OF BIAS OF THE STUDIES INCLUDED