Review question
We wanted to know how important it is to leave a nephrostomy tube (which connects the inside of the kidney to the skin) or a ureteral stent (a small tube that goes from the inside of the kidney through the ureter to the bladder) in people after a percutaneous kidney stone removal operation (percutaneous nephrolithotomy [PNL]).
Background
Kidney stones is a common disease worldwide. PNL is a method to remove stones from the kidney by creating a connection between the skin and the inside of the kidney where the stones are. This connection allows the urologist to put a small scope and other instruments into the kidney. The surgeon can use these instruments to break up and remove the stones. Based on the size of the connection, this procedure is referred to as simply PNL or mini-PNL. After the procedure, urologists oftentimes leave a nephrostomy tube, which ensures the channel from the kidney to the skin and might help to stop bleeding within the channel; this is known as standard PNL. However, the surgeon may also push a ureteral tube (stent) from the kidney to the bladder to ensure the urine drainage from the kidney to the bladder, with no nephrostomy tube (tubeless PNL). A third alternative is to leave the patient without a nephrostomy tube or a stent (so-called totally tubeless PNL). However, it is unclear which of these methods is best.
Study characteristics
The information in this review is current to September 2022. We included studies where chance determined what treatment people in the study would get. We evaluated participant data on severe adverse effects, pain at day one, length of hospital stay, and necessity for blood transfusions. We also investigated whether people in the different treatment groups had fever or signs of infection after surgery or had to be rehospitalized after discharge.
Key results
Tubeless PNL versus standard PNL: We are very uncertain how severe adverse events compare between the two approaches. Pain on day one after surgery may be no different, and operating room time is probably not different between treatment groups. Tubeless PNL may reduce length of hospital stay. We are very uncertain how blood transfusions, sepsis/fever, or readmissions compare between the two approaches.
Totally tubeless PNL versus standard PNL: Totally tubeless PNL may reduce severe adverse events compared to standard PNL. It may also reduce pain on day one after surgery, but there is probably little to no difference between groups in operating room time. Totally tubeless PNL probably reduces length of stay. We are very uncertain how blood transfusions and readmissions compare. Totally tubeless PNL may result in little to no difference in sepsis/fever.
Tubeless mini-PNL versus standard mini-PNL: We did not find any studies for this comparison.
Totally tubeless mini-PNL versus standard mini-PNL: We did not find any studies for this comparison.
Certainty of evidence
The certainty of evidence by outcome ranged from moderate to very low, mainly because of study limitations and imprecision due to small studies with few events. This means that we have moderate to very little confidence in these results, respectively.
When comparing tubeless to standard PNL with regard to the predefined primary outcomes of this review, there may be little difference in early postoperative pain, while we are very uncertain of the effect on SAEs. People treated with tubeless PNL may benefit from a reduced length of stay compared to standard PNL. When comparing totally tubeless to standard PNL, early postoperative pain and severe adverse events may be reduced with totally tubeless PNL. The certainty of evidence by outcome was mostly very low (range: moderate to very low) for the comparison of tubeless to standard PNL and low (range: moderate to very low) for the comparison of totally tubeless to standard PNL. The most common reasons for downgrading the certainty of the evidence were study limitations, inconsistency, and imprecision. We did not find randomized trial evidence for other comparisons. Overall, further and higher-quality studies are needed to inform clinical practice.
Percutaneous nephrolithotomy (PNL) is the standard of care for removing large kidney stones (> 2 cm). Once the procedure is complete, different exiting strategies exist to manage the percutaneous tract opening, including placement of an external nephrostomy tube, placement of an internal ureteral stent, or no external or internal tube. The decision to place or not place a tube is handled differently among clinicians and may affect patient outcomes.
To assess the effects of tubeless PNL (with ureteral stenting), totally tubeless PNL (without ureteral stenting or nephrostomy), and standard PNL (nephrostomy only) for the treatment of kidney stones in adults.
We performed a systematic literature search in multiple biomedical databases (CENTRAL, MEDLINE, Embase, Web of Science), as well as in two clinical trial registries. We also handsearched reference lists of relevant publications and conference proceedings. We applied no language restrictions. The latest search update was conducted in September 2022.
We included randomized controlled and quasi-randomized controlled trials of adult patients who received tubeless, totally tubeless, or standard PNL for treating kidney stones. We defined tubeless PNL as no nephrostomy tube, but ureteral stenting, while totally tubeless PNL meant no nephrostomy tube or ureteral stenting. Both interventions were compared to standard PNL with placement of a nephrostomy tube (only). We considered access tubes of any sizes. We only considered unilateral PNL with single-tract access. There were no exclusions on stone composition, size, or location.
Two review authors independently screened the literature, extracted data, assessed risk of bias, and rated the certainty of evidence using GRADE. Primary outcomes were severe adverse events and postoperative pain, and secondary outcomes were operating time, length of hospital stay, and stone-free rate. We used the random-effects model for meta-analysis.
We included 10 studies in the review. Participant age varied among studies, ranging from 20 to 60 years. Detailed information on stone characteristics was rarely presented.
Tubeless PNL versus standard PNL
We are very uncertain whether there is a difference in severe adverse events (SAEs) between tubeless PNL and standard PNL (risk ratio (RR) 1.53, 95% confidence interval (CI) 0.14 to 16.46; I2 = 42%; 2 studies, 46 participants; very low-certainty evidence). Tubeless PNL may have little to no effect on pain on postoperative day one (mean difference (MD) 0.56 lower, 95% CI 1.34 lower to 0.21 higher; I2 = 84%; 4 studies, 186 participants; low-certainty evidence), and probably results in little to no difference in operating room time (MD 0.40 longer (in minutes), 95% CI 4.82 shorter to 5.62 longer; I2 = 0%; 3 studies, 81 participants; moderate-certainty evidence). Tubeless PNL may reduce length of hospital stay (MD 0.90 shorter, 95% CI 1.45 shorter to 0.35 shorter; I2 = 84%; 6 studies, 238 participants; low-certainty evidence). We are very uncertain of the effect of tubeless PNL on blood transfusions (RR 0.64, 95% CI 0.16 to 2.52; I2 = 0%; 4 studies, 161 participants; very low-certainty evidence), sepsis or fever (RR 0.50, 95% CI 0.05 to 4.75; I2 = not applicable; 2 studies, 82 participants; very low-certainty evidence), or readmissions (RR 1.00, 95% CI 0.07 to 14.21; I2 = not applicable, 1 study, 24 participants; very low-certainty evidence).
Totally tubeless versus standard PNL
Totally tubeless PNL may result in lower SAE rates (RR 0.49, 95% CI 0.19 to 1.25; I2 = 0%; 2 studies, 174 participants; low-certainty evidence) and pain on postoperative day one (MD 3.60 lower, 95% CI 4.24 lower to 2.96 lower; I2 = Not applicable; 1 study, 50 participants; low-certainty evidence). Totally tubeless PNL may result in little to no difference in operating room time (MD 6.23 shorter (in minutes), 95% CI 14.29 shorter to 1.84 longer; I2 = 72%; 2 studies, 174 participants; moderate-certainty evidence) and sepsis or fever (RR 0.33, 95% CI 0.01 to 7.97; I2 = not applicable; 1 study, 90 participants; low-certainty evidence). Totally tubeless PNL likely shortens the length of hospital stay (MD 1.55 shorter, 95% CI 1.82 shorter to 1.29 shorter; I2 = 0%; 4 studies, 274 participants; moderate-certainty evidence). We are very uncertain of the effect of totally tubeless PNL on blood transfusions (RR 0.62, 95% CI 0.26 to 1.48; I2 = 0%; 4 studies, 274 participants; very low-certainty evidence) or readmissions (RR not estimable, 95% CI not estimable; I2 = not applicable; 1 study, 50 participants; very low-certainty evidence).
We found no studies comparing tubeless mini versus standard mini-PNL or totally tubeless mini versus standard mini-PNL.