PUJ Obstruction & Ureteric
Stricture Specialist, London
Expert robotic-assisted reconstruction of the kidney drainage system — including pyeloplasty and ureteric reimplantation — with faster recovery than open surgery.
Book a Consultation Send an EnquiryImportant: Obstruction to the flow of urine from the kidney — whether at the pelvi-ureteric junction or along the ureter — can cause pain, recurrent infections, and progressive kidney damage if left untreated. Early specialist assessment and, where appropriate, surgical reconstruction can protect kidney function and resolve symptoms. All reconstructive procedures performed by Mr Sri are robotic-assisted.
Understanding the two conditions
The kidney drains urine into the bladder through a collecting system. Obstruction can occur at two key points — at the junction between the kidney and the ureter (the PUJ), or along the ureter itself. Each has distinct causes and a tailored surgical approach.
The pelvi-ureteric junction (PUJ) is the point where the kidney's renal pelvis narrows into the ureter. When this junction is obstructed — either congenitally (present from birth) or acquired — urine cannot drain freely from the kidney, causing it to swell (hydronephrosis).
PUJ obstruction is often discovered incidentally on imaging — either during investigation for loin pain or recurrent infections, or as an incidental finding on a scan performed for another reason. It is one of the most common causes of hydronephrosis in young adults.
A ureteric stricture is a narrowing of the ureter — the tube connecting the kidney to the bladder — that restricts urine flow. Strictures may arise from prior surgery, endoscopic procedures, radiotherapy, previous stone disease, infection, or inflammatory conditions. They can affect the upper, mid, or lower ureter.
The site and length of the stricture guide the surgical approach. Lower ureteric strictures — close to the bladder — are typically managed with ureteric reimplantation, while upper ureteric strictures may require more complex reconstruction.
How these conditions are diagnosed
Diagnosis requires a combination of imaging and functional assessment. Mr Sri will review all existing investigations at consultation and arrange any further tests needed before planning treatment.
A MAG3 renogram — an isotope scan measuring differential kidney function and drainage — is a critical investigation before any reconstructive procedure. It establishes how much the affected kidney is contributing relative to the other side, and whether obstruction is present on drainage. This guides the decision between reconstruction and, in cases of very poor function, nephrectomy.
Treatment options
The right treatment depends on the site and cause of obstruction, the degree of hydronephrosis, kidney function on the affected side, symptom burden, and patient fitness. Mr Sri will discuss all options clearly at your consultation.
The definitive treatment for PUJ obstruction. The narrowed segment at the pelvi-ureteric junction is excised and the kidney pelvis is refashioned and joined to the ureter below — creating a wide, unobstructed drainage pathway. This is an Anderson-Hynes dismembered pyeloplasty in the majority of cases, which also allows crossing lower pole vessels to be transposed where they are contributing to the obstruction.
Performed entirely robotically, Mr Sri uses the da Vinci system to achieve the precision suturing that this reconstruction demands — working in a small operative field around delicate structures. The robotic approach avoids a large flank incision, significantly reducing recovery time compared to open surgery.
A ureteric stent is placed at the time of surgery to protect the repair and allow it to heal. This is typically left in place for 4–6 weeks and removed with a flexible cystoscopy under local or general anaesthetic.
Where the stricture is in the lower ureter — close to the bladder — the affected segment of ureter is excised and the healthy ureter above is reimplanted directly into the bladder through a new opening. This is the treatment of choice for lower ureteric strictures, whether caused by previous surgery, radiotherapy, endoscopic injury, or stone-related scarring.
For longer strictures where the ureter has shortened, a Psoas hitch or Boari flap — techniques that mobilise and advance the bladder to bridge the gap — may be used to achieve a tension-free anastomosis. All of these techniques are performed robotically, offering the precision and visualisation needed for reconstructive work in the pelvis.
As with pyeloplasty, a ureteric stent is placed at the time of surgery and removed by flexible cystoscopy at 4–6 weeks.
A ureteric stent — a soft plastic tube running from the kidney to the bladder — can be placed endoscopically to bypass an obstruction and restore drainage. Stenting is used as a temporary measure while awaiting definitive reconstruction, in patients not fit for surgery, or in palliative settings where definitive repair is not appropriate.
Stents require regular exchange (typically every 3–6 months) and carry associated symptoms including urinary frequency, urgency, and occasionally discomfort. They are not a long-term solution in most patients who are fit for reconstruction.
Where the affected kidney has lost the majority of its function — typically shown by contributing less than 20% of overall renal function on isotope scanning — reconstruction may not be beneficial and removal of the kidney (nephrectomy) is the appropriate treatment. This relieves symptoms, eliminates the risk of recurrent infections, and removes a non-contributing organ.
As with all surgery in Mr Sri's practice, nephrectomy is performed robotically — typically using a retroperitoneal approach — with the benefits of minimally invasive surgery in terms of recovery.
The stent — what to expect
A ureteric stent — a soft, flexible tube running internally from the kidney to the bladder — is placed at the time of reconstruction. It sits entirely inside the body and is invisible externally. Its purpose is to protect the repair, maintain drainage, and allow the anastomosis to heal securely.
The stent is typically left in place for 4–6 weeks. During this time, it is common to experience some urinary frequency, urgency, or a mild aching sensation in the loin — particularly when passing urine. These symptoms resolve completely once the stent is removed.
Stent removal is performed at an outpatient flexible cystoscopy appointment under local anaesthetic. The procedure takes only a few minutes and patients go home immediately afterwards. Most find it well tolerated.
Why robotic surgery — recovery compared
Pyeloplasty and ureteric reimplantation were historically performed through large open incisions requiring a prolonged hospital stay and weeks of restricted activity. Robotic surgery achieves the same reconstruction through small keyhole incisions, with significantly better recovery for patients.
The precision of robotic instrumentation — wristed instruments, 10x magnification, and three-dimensional visualisation — is particularly valuable in reconstructive surgery, where the quality of the anastomosis (join) directly determines the long-term success of the repair. Robotic reconstructive surgery for this reason is considered suprior to laparascopic and open techniques. Mr Sri has extensive experience in robotic upper and lower tract reconstruction as part of his subspecialty practice.
Related Conditions
PUJ obstruction and ureteric stricture can present with blood in the urine or recurrent urinary tract infections. If either of these is a feature of your presentation, please also visit the relevant pages — haematuria investigation runs in parallel to obstruction assessment and should not be delayed.
Frequently asked questions
Clinic locations
Mr Sri sees patients at three private hospital locations in and around London.
Cheam, Surrey SM3 9DW
Tel: 020 8337 6691
Wimbledon SW19 5NX
Tel: 020 8971 8000
Marylebone W1G 7AF
Tel: 020 379 77248
Diagnosed with obstruction or a ureteric stricture?
Same-week appointments available. No GP referral required.
Self-pay and all major insurers accepted.