Ureteral Stent Placement and Removal

Obstructed infected kidney - pyonephrosis behind a stone is drained mechanically, not treated with antibiotics, and instrumenting it pushes bacteria into the circulation. Expect SVR to fall minutes after the surgeon enters the system: antibiotic in first, pressor running before the scope goes in.

Decompression is the resuscitation - source control takes fifteen minutes, and every minute the pus stays under pressure the patient stays septic. Get large-bore access and a vasopressor going, and put the arterial line in while they prep rather than holding the case for it.

Induction in the septic patient - they are vasodilated and volume-depleted, and the pressure they arrived with is held up by sympathetic tone that a standard propofol dose removes. Cut the dose and give it slowly, or use ketamine or etomidate, with vasopressor support around induction rather than after.

Low irrigation pressure, minimal contrast - pressurized retrograde irrigation and a hand-injected pyelogram both raise pressure in a space with nowhere to vent, and that is what drives the backflow. Ask out loud for gravity irrigation, minimal contrast, and drainage as the only goal today.

The elective stent - a scheduled exchange in a well patient is fifteen minutes of cystoscopy with no incision, so a supraglottic airway or propofol sedation covers it and paralysis buys nothing. Only the scope through the external sphincter and the ureteric orifice stimulate, and there is no closure to warn you.

Lithotomy for a short case - the stirrup compresses the common peroneal nerve against the fibular head, so pad both legs laterally and raise and lower them together and slowly. Dropping the legs takes preload abruptly, which is unremarkable in a well patient and is not in a septic or elderly one.

Bladder distension - filling against a closed outlet gives vagal bradycardia and hypotension in some patients, so ask for it to be drained rather than escalating treatment. Above T6 cord injury it is autonomic dysreflexia instead, and those patients come back repeatedly for exchanges.

The C-arm in the room - fluoroscopy runs through every part of this case, so lead and a thyroid shield go on beforehand and a few feet back drops your scatter dose. Expect the table turned and the C-arm swung into your circuit, and expect pregnant patients, who need the plan agreed before the case starts.

Renal function and post-obstructive diuresis - obstruction damages the kidney behind it, so a raised creatinine is the rule and renally cleared drugs are dosed against that. After drainage the diuresis is real salt and water and runs to liters on the ward, so hand it over and ask for measured output.

Stent discomfort, not surgical pain - the distal curl irritates the trigone, giving frequency, urgency, and flank pain exactly on voiding as bladder contraction refluxes urine up the stent. Warn the patient beforehand, do not chase it with opioid in recovery, and treat severe or febrile pain as sepsis.

A ureteric stent is a double-J tube that sits with one curl in the renal pelvis and the other in the bladder, restoring drainage past an obstruction. The obstruction is usually a stone, but it can equally be a urothelial tumor, a stricture, or a pelvic mass compressing the ureter from outside. Obstructed urine backs pressure up the collecting system, producing hydronephrosis and a falling filtration rate on that side. If that trapped urine is infected, the closed system becomes pyonephrosis: pus under pressure that no antibiotic reaches in useful concentration because nothing is flowing through it. Raised intrapelvic pressure then drives pyelovenous and pyelolymphatic backflow, pushing bacteria and endotoxin straight into the venous and lymphatic circulation. That is why an obstructed infected kidney is decompressed as an emergency, and why the pressure generated inside that system during the case is an anesthetic problem and not only a surgical one.

Cystoscopy - The patient is in lithotomy and a rigid cystoscope is passed per urethra into the bladder. The urethra and bladder are inspected and the ureteric orifice on the affected side is identified. In a stent exchange, the old stent is grasped and pulled down first, often over a wire so ureteric access is never lost.

Guidewire up the ureter - A guidewire is advanced through the ureteric orifice, usually through a 5 or 6 French open-ended ureteric catheter for support, and pushed until its floppy tip coils in the renal pelvis under fluoroscopy. This is the step that fails: impacted stones, tight strictures, tumor, and tortuous ureters can all stop the wire, and the surgeon may work through several wire types before it passes. The obstruction only has to be crossed once.

Retrograde pyelogram - Dilute contrast is injected retrograde through the open-ended catheter to outline the renal pelvis and show where the obstruction is. Only a small amount of dilute contrast is used deliberately, because an opaque pelvis hides the catheter and the stent tip. Contrast is being injected into a closed space upstream of an obstruction, which matters enormously if that space is infected.

Length measurement and stent selection - Ureteric length is measured off the markings on the ureteric catheter, and a stent is chosen to match. Stiffer and larger diameter stents are chosen for infected kidneys and tight strictures because they resist compression and drain better; a metallic stent may be used for malignant compression or when the stent will be permanent.

Stent deployment - The double-J is railroaded over the wire with a pusher until the proximal curl forms in the renal pelvis and the distal curl sits in the bladder, confirmed on fluoroscopy and by seeing the stent marker at the ureteric orifice. The wire is withdrawn last, so ureteric access is preserved until the surgeon is satisfied with the position.

Dangler thread or no thread - A safety string may be left attached to the distal end and taped to the inner thigh or penis so the stent can be pulled out on the ward or in clinic without a scope. This is used when the stent is only needed for a week or so, because the string is also easy for the patient to dislodge accidentally. Otherwise the thread is cut and removed and the stent is retrieved later cystoscopically.

The infected case is a different operation - When the indication is an obstructed infected kidney, the goal is drainage and nothing else: cross the obstruction, drop a stent, drain the pus, get out. Definitive stone treatment is deferred until the infection is controlled. For the sickest patients the urologist or interventional radiologist may choose a percutaneous nephrostomy instead, because it avoids manipulating the infected stone at all and does not risk failing to bypass the obstruction from below.

Stent removal - Most stents come out in clinic, either by pulling the string or with a flexible cystoscope under topical lidocaine gel, with no anesthesia provider involved. A stent that has been in too long is a different problem: it encrusts, becomes adherent, can migrate or fragment, and may need a formal cystoscopic or even percutaneous operation to retrieve, sometimes with lithotripsy to clear the encrustation off it.

Most stent removals never reach an anesthesia provider, and knowing why yours did tells you what case you have - The routine removal is a clinic procedure: the string is pulled, or a flexible cystoscope goes in under lidocaine gel, and it takes a minute. Four things bring it to your list instead. Children, who will not tolerate a scope awake and need a general anesthetic for what is a thirty-second procedure. Adults who genuinely cannot tolerate cystoscopy awake, including those with severe anxiety, chronic pelvic pain, or a hostile urethra from stricture or prior surgery. A retained or encrusted stent that has been in for months and needs a formal operation with rigid instruments, sometimes lithotripsy to break the encrustation off it, and sometimes a percutaneous approach as well. And spinal cord injured patients, where the autonomic reflex rather than the pain is the reason for anesthesia. Ask which of those it is, because the first two are a five-minute mask or supraglottic case and the third is a proper operation on a patient who has had an infected foreign body in situ for a long time.

The forgotten stent is a real clinical entity and it arrives as a much bigger operation - Stents have a maximum indwelling time and are supposed to be exchanged or removed on schedule, and in pregnancy that interval is short because encrustation is rapid. Patients get lost to follow-up, move, or simply forget, and the stent that was left for six weeks has been in for two years. It encrusts, forms stones on both curls, migrates, and can fragment, and retrieving it becomes a combined cystoscopic and percutaneous case with lithotripsy, real time, real irrigation, and a colonized urinary tract. If the booking says stent removal but the history says the stent has been in for over a year, plan the anesthetic for the retrieval operation rather than for the two-minute clinic procedure the name implies.

Percutaneous nephrostomy is the alternative, and it takes you somewhere else - For the sickest patients the plan may switch from a retrograde stent to a percutaneous nephrostomy, because puncturing the kidney from the flank avoids manipulating the infected stone at all and does not risk failing to cross the obstruction from below. That decision changes your day completely: the patient is prone or in a flank position rather than lithotomy, the procedure is frequently done in interventional radiology rather than the operating suite, and you are now anesthetizing a septic patient in a room designed around a scanner. If that is on the table as a possibility, settle before the patient moves whether you are going with them, what monitoring and drugs travel, and how help arrives in that room.