Introduction:
The “cut-to-the-light” technique was first performed by Bagley in 1985 in a patient with complete renal pelvis-ureteral junction obstruction after pyelolithotomy (a surgical procedure performed for removing the stone in the renal pelvis). With an increase in the prevalence of urolithiasis (kidney stones) worldwide, higher success rates and lower complication rates of ureteroscopy (the examination of the upper urinary tract, involving a ureteroscope that is passed through the urethra and the bladder, and then into the ureter) have been documented due to improvements in stone-disintegration devices.
The cut-to-the-light technique has shown great results. It has proved to be a minimally invasive technique that can be used as an alternative to conventional invasive methods. However, studies with larger samples are still required, with a long-term follow-up to understand the benefits and drawbacks of this method in detail.
Endoscopic treatments are usually used as the first line of treatment with a high success rate (around 55 to 85 percent). It is often used in patients with a short or less than two centimeters of stricture, a complex stricture, or an obliterated ureter with a renal function of greater than 20 percent. It has been documented that most stricture recurrences are identified within the first year after surgery.
What Is Ureteral Stricture?
A ureteral stricture is a serious and delayed complication of ureteroscopy. It is a narrowing lumen of the ureter. Further, leading to functional obstruction of the kidney, which is usually a silent process and leads to progressive loss of ipsilateral (occurring on the same side of the body) renal function.
Therefore, it is important to use correct and convenient ureteral stricture treatment methods to preserve renal function. The management of post-ureteroscopy stricture can be done with several options, including:
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Open repair.
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Laparoscopy (a diagnostic or therapeutic intervention where small incisions are made in the abdomen).
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Robotic and interventional techniques.
Ureteroscopic treatment of ureteric stones is now considered safe with high success rates owing to the ureteroscopic enhancements and improvements in intracorporeal lithotripsy devices. The rate of complications has reduced to less than two percent. Postoperative ureteral stricture accounts for less than 0.5 percent of complications.
The following features appear on histological examination of ureteral strictures:
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Collagen deposition.
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Fibrosis.
What Is a “Cut-to-the-Light” Technique Laser Endoureterotomy for Complete Ureteral Obstruction?
The ideal choice for endoureterotomy for complete ureteral obstruction is the holmium laser because of the following reasons:
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It is compatible with a flexible endoscope.
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It has a hemostatic effect.
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It is easily procurable.
The full-thickness incision is created in the endo-ureterotomy procedure done from the ureteral lumen up to the periureteral fat, including two to three millimeters of normal proximal and distal tissues. The procedure is started by making a tiny laser ureteral incision, followed by ureteral dilatation to complete a full-thickness incision as such to overcome any damage to nearby structures. It is a general rule to incise upper ureteral strictures posterolaterally. However, in distal ureteral strictures, the incision is made along the anteromedial wall to avoid damage or nearby vessel injury.
At the end of the procedure, a ureteral double J stent is placed as ureteral stent placement is a routine practice after endo-ureterotomy. This is done to prevent extra ureteral leakage of urine that helps ureteral healing and prevents ureteral stricture recurrence caused by an ischemic event of the ureter around the stent.
Contrast pyelography is a useful method for evaluating whether endo-ureterotomy can be performed. The main step is to pass a guidewire from one lumen to another under direct vision with fluoroscopic guidance. During the surgical procedure, the cut is made at one end and guided towards the light source from the ureteroscope on the opposite end of the stricture.
A study was conducted on 35 patients with benign ureteral stricture on whom laser endo-ureterotomy was performed, and the results showed that 79 percent had no radiological evidence of obstruction and 82 percent of patients were symptom-free.
Another study documented that a stricture length above two centimeters is responsible for treatment failure, and non-ischaemic strictures or stricture lengths less than one centimeter show greater success rates. Several studies suggest a combined approach for strictures less than two centimeters, as the use of the combined technique for complete ureteral obstruction, has demonstrated successful outcomes.
What Is the Success Rate of This Treatment?
The success rate of Ho: YAG laser fiber during endo-ureterotomy is around 53 to 88 percent. The main feature of an efficacious treatment is prompt diagnosis and early intervention to prevent obstructive complications. Since this treatment protocol has shown tremendous improvement in endoscopy, the less-invasive endo-ureterotomy is regarded as an important treatment option for treating post-ureteroscopy ureteral strictures and is now replacing older invasive interventions.
Several other treatment options can also be used, like cutting devices (cold knife, laser fiber, electrocautery) under direct ureteroscopic vision or cutting balloon catheters using fluoroscopic guidance. These methods have shown favorable results.
The patient must be monitored for two to four weeks after stent removal, and early follow-up imaging must be performed, like renal ultrasonography, intravenous pyelogram (IVP), or renal scintigraphy. If the patient is asymptomatic, this can be delayed by up to three months, and then imaging is done at an interval of six months for the first two years.
When the efficacy and safety of double versus single ureteral stent placement were compared after laser, it was documented that in the case of benign ureteral strictures of greater than 1.5 centimeters, a greater success rate was achieved with double stent placement of the ureter after laser endo-ureterotomy in comparison to single stent placement. However, the mechanism is still not understood completely, and further research is required to explain the benefits of this technique.
Conclusion:
Finally, the “cut-to-the-light” technique has shown excellent outcomes in treating ureteral strictures. However, longer follow-ups are required, along with comparative studies using traditional techniques, in order to completely understand the advantages of this method and to further elucidate its suitable uses and drawbacks. Other invasive techniques are now being used depending on the stringent criteria of patient selection, including patients with complex strictures who have undergone radiation or have been operated on in the past. Other techniques include robotic-assisted corrections and buccal mucosa graft urethroplasty. However, not much data is available associated with long-term monitoring of ureteral stricture treatment.
