Plenary Lecture at 24 Malaysian Urological Conference, Johor Baru, 21 November 2015
The "Perfect" ESWL
by Dr Clarence
C M Lei
Kidney &
Urology Centre, Normah Hospital, Kuching, Malaysia
Introduction:
Urinary stone
management comprises at least a third of urology practice. The classical
presentation is a loin to groin acute colic in a young (30 to 60 years old)
man. Prevalence is about 5 to 15%. Microhaematuria
is a useful clue to diagnosis. Imaging
to confirm the stone is often possible with clinic ultrasound and plain
x-ray. Nevertheless, the gold standard
investigation is a non-contrast low dose CT urography.
Methods:
ESWL,
extracorporeal shockwave lithotripsy is the greatest advance in modern urology.
It was first reported by Chaussy C et al in the Journal of Urology, 1982; 127:
417. The author has been using ESWL since
1989. His personal experience with
lithotripters include Siemens (GHKL, 1991 – 1995), Edap (1996 – 1997) and the
Dornier Compact (since 1998). Early
experience in GHKL recorded about 2000 cases of ESWL per annum. In more recent years, the number of cases
done is about 200 per annum.
Results:
Selection of
the appropriate patient and stone is the most important factor for a successful
ESWL. If the patient has an obvious urinary tract infection, this
should be treated. Parenteral antibiotics should be given during ESWL in such
cases. More than 50% of the stones would
be suitable for ESWL: more than 6 mm in size, but with a maximum diameter of <
20 mm. Upper urinary tract stones
(except for the lower pole) are ideally suitable, whereas lower urinary tract
stones can be treated endoscopically with a success rate of almost 100%. The few contraindications for ESWL include: pregnancy,
gross obesity, uncorrected coagulopathy, nearby vascular calcifications and a non-functioning
kidney. Informed consent is should be obtained. The patient should be aware that the overall stone free rate is
about 80%. I would also not persist if there is little fragmentation after 3
sessions, usually given every other day.
The alternative options with its complications and success rates should
also be made known to the patient during the informed consent process. The patient should also be informed of the
complications of ESWL, viz bleeding (1 in 178 patients with significant
perinephric haematoma in the author’s series), obstruction by the stone
fragments, with up to 5% of patients requiring urgent ureteric stenting
especially if there is fever.
The following
technical points deserve attention during the ESWL: air pockets trapped in the
coupling gel between the shockhead and the patient significantly reduced the
delivery of shockwave energy. Delivery of the shockwave at 60/min versus 90/min
results in a stone free rate at 3 months of 91 versus 80% respectively. There
should be adequate analgesia: pre-medication with analgesics, anaesthetic cream
and intravenous analgesia during ESWL. With sufficient analgesia, ESWL can be
delivered with maximal power and number of shocks. Accurate localisation of the stone with x-ray
or ultrasound is important and this must be continuously monitored, say, every
200 shocks. The patient should have
follow-up documentation to show that the patient is stone free or has stable
stone fragments.
ESWL treatment
should be part of holistic management: e.g. co-existing diabetes, hypertension
and chronic kidney disease. All the
lithotripsy medical staff should be credentialed in ESWL. Stone Clinic staff should know about stone
management, treatment of complications, other treatment options and the
prevention of further stone episodes. The most important prevention is the
adequate intake of fluid such that the patient produces 2 to 3 litres of urine
per day. Serum calcium, uric acid and urine culture should be reviewed in all
patients.
Conclusion:
ESWL remains a
mainstay treatment for urinary stones.
The treatment of most upper urinary tract stones less than 20 mm is
rewarding. Selection of stone size,
localisation, ESWL techniques, follow-up and stone prevention are important. Stone treatment should be given as part of the
holistic management of patient.
