Extracorporeal shockwave lithotripsy (SWL or lithotripsy) has successfully been used to treat renal tract stones since the early 1980s. The treatment relies on the human body being mostly made of water to allow the passage of shockwaves through tissues which impact on the stones within the kidney or ureter and break them up into small pieces which can be easily passed out through urine. Lithotripsy has revolutionised the treatment of stones which previously relied on operations that left patients in hospital for days and took many weeks for recovery.
The initial machines were so powerful that patients had to have a general anaesthetic and be held in a bath of water, but over time the machines have become smaller, the technology more reliable and anaesthetic requirements have reduced. With more experience it has been discovered that there are limitations to the types of stones that can be treated and the initial hope that all stones could be cleared using this non-invasive treatment have been tempered.
It is now reserved for stones less than 2cm in maximum size and there may also be patient factors that make successful treatment less likely, such as a long calyceal infundibulum or a calyceal diverticulum. Lithotripters are extremely good at breaking up stones but the fragments may not drain away. Patient selection is therefore critical.
Direct GP access to lithotripsy service at Monash Health
A Storz Medical Modulith SLK In-line lithotripter was installed within a specially designed room within Diagnostic Imaging at Casey Hospital in December 2014. This is only the second public lithotripter in Victoria. The new service had been in the planning phase for over 2 years and was a unique collaboration between the Imaging, Paediatric Surgery and Urology departments. It allows Monash adult and paediatric urologists to offer patients with urinary stones all possible treatments on one site and confirms Casey Hospital’s position as one of the busiest and most innovative stone units in the country. It is the only site in the state where children with stones can be fully treated.
Since installation over 1000 treatments have been successfully performed.
The new service differs in a number of ways to those offered elsewhere in Australia:
1. Adult patients are treated without general anaesthesia, routinely being given just non-steroidal anti-inflammatories with top-up opiates as necessary. This allows treatment outside the confines of operating theatres with a more rapid turnover and access to treatment up to 10 sessions/week.
2. Not all stones are suitable for lithotripsy and all referrals are assessed at a weekly stone meeting. If felt appropriate other treatments can be suggested and booked.
3. Patients are reviewed in a dedicated stone clinic both to ensure continuity of treatment and to enable auditing of results. Complex stone forming patients will be assessed by a multi-disciplinary team to try and prevent further stone formation.
4. Patients with urgent admissions for renal colic due to ureteric stones can be treated immediately (in-situ lithotripsy) which reduces the need for urgent operations that may need to be repeated.
By using the Casey Lithotripsy Consultation form (or the on-line form) any doctor, including General Practitioners, can directly access the service. We have created a streamlined route for all patients, both public and private, with renal tract stones. It is important that all elements of the form are completed, particularly the radiology provider details. We can access most imaging throughout the state which means patients will not have unnecessary repeat radiation exposure. There will be no need for referral letters, patients can avoid waiting for out-patient appointments and the information provided will be assessed by dedicated stone specialists ensuring the most appropriate treatment. If the stones are considered not suitable for lithotripsy then the patient can be advised which other treatment may be the best for their particular problem.
Our intention is to provide all elective patients lithotripsy within 28 days of referral, and treat urgent stones (patients with colic) within 24 hours.
We want to provide as much support to GPs as possible and are happy to provide roadshows or demonstrations within the unit.
Further information can be obtained from the urologists Philip McCahy, Shekib Shahbaz and Tony De Sousa or from the unit secretary, Annette Swaby (87681490).
Picture above: Storz SLK Modulith In-line lithotripter in dedicated treatment room
Picture above: listening to iPad during treatment
Picture above: Control Monitor (243 shocks into treatment – normal about 3000/session)
Picture above: Ultrasound monitor for stone localisation showing kidney
Picture above: First pediatric treatment with Nathalie Webb, Shekib Shahbaz, Fritz Knödgen (Storz Medical technician), Philip McCahy and Brad Newell
Picture above: The Lithotripsy Team