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EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY: Complications and Their Prevention

PANKAJ N MAHESHWARI*, MUKUND G ANDANKAR**, AMIT L SAPLE***, AJAY T OSWAL****

*Chief Urologist, RG Stone Urological Research Institute, Mumbai; **Lecturer, BYL Nair Hospital, Mumbai; ***Urologist, Seven Hills Hospital, Vishakhapatnam; ****Urologist, Kamalnayan Bajaj Hospital and MMRC, Aurangabad; India.

As the world moves from invasive modalities of therapy to non-invasive ones in all fields of medicine, one invention stands out as the most revolutionary invention of the century : Extra corporeal shock-wave lithotripsy. What was a mere figment of some-one’s imagination has become an actual reality with the advent of ESWL. The Hippocratic Oath that "I will never cut for a Stone" has become a welcome reality with the help of ESWL! ESWL has shown excellent success rates in treatment of urinary calculi. ESWL has now become the leading mode of management of urinary calculi. It has come a long way from the day of its accidental discovery in relation to aircraft technology unto its safe use in humans.

However, that leaves us with the question : How safe is ESWL?

ESWL is unparalleled modality of treating urinary stones as regards its non-invasive nature; minimal morbidity; decreased length of hospitalization and anaesthesia requirements. But as our experience with ESWL grows, we are uncovering an ever-increasing number of complications of ESWL. What was touted as a modality with no side effects is proving to be not so innocuous! Many consider ESWL a panacea for the urinary stone disease. Lay press and the general population also carries the false perception that ESWL is a cure for all, absolutely safe and without long-term adverse effects. This has sadly been a belief that has been popularized by many business enterprises. It is an established fact that ESWL is safe and effective in ‘properly selected patients’. Contrarily there are innumerable animal studies and human trials that have documented injury to the kidney and adjacent structures that are apparent either immediately or on long follow-up.

For the sake of discussion the complications of ESWL can be divided in either immediate or delayed (Table 1). Proper evaluation and care can avoid most of these undesirable adverse effects. The vital components of this evaluation are complete urological investigations like sonography, intravenous urography and other radiological tests when indicated.[1] Complete coagulation profile and urine culture and sensitivity tests are necessary before ESWL.

TABLE 1
Complications of ESWL
Immediate Delayed
Pain Renal functional loss
Urinary infection Hypertension
Obstructive uropathy Steinstrasse
Haematuria Residual calculi
Disrhythmias Recurrent calculi
Renal and perirenal haematoma  
Surrounding organ injury  


ESWL is contraindicated during active urinary infection. At this time if ESWL is administered, there can be flare-up of infection, septicaemia and pyelonephritis.[2] The incidence of pain, fever and haematomas is also higher. Urinary infection needs to be treated before ESWL. This is achieved by a proper selection of antibiotics. Some patients may need double J stent or percutaneous nephrostomy for control of infection.[3]

A proper case selection goes a long way in reduction of ESWL related complications. Only those patients would be ideal for treatment if complete, stone clearance can be achieved in less than three sessions of ESWL. Larger stone load for ESWL would entail need for multiple sessions, steinstrasse, residual calculi and renal functional loss.[4] A need for frequent endourological treatment of steinstrasse and residual calculi is a definite sign of wrong case selection for ESWL.

Pain during ESWL depends on the type of energy source and the amount of energy used. Need for analgesia is higher in women, younger patients or patients where a higher voltage is applied.[5] Pain also correlates directly to patient’s anxiety status;[6] hence patients perceive more pain in the first session of ESWL and are more comfortable later on. It is important to start the ESWL at a lower voltage and gradually increase the voltage as the treatment progresses. This gives patient time to be acclimatized to the treatment.

Pain during ESWL depends on the type of energy source and the amount of energy used. Need for analgesia is higher in women, younger patients or patients where a higher voltage is applied.[5] Pain also correlates directly to patient’s anxiety status;[6] hence patients perceive more pain in the first session of ESWL and are more comfortable later on. It is important to start the ESWL at a lower voltage and gradually increase the voltage as the treatment progresses. This gives patient time to be acclimatized to the treatment.

Minor, self-limiting haematuria after ESWL is quite frequent. Severe haematuria should raise a suspicion of coagulopathy or uncontrolled infection. Renal and perirenal haematoma occur in about 0.1 to 0.3% patients. Haematoma are more common in patients with uncontrolled hypertension, diabetes mellitus or coagulopathy. They are more frequent in elderly patients, recurrent calculi or patients with past history of ESWL.[7] Haematoma should be suspected in patients with unexplained continuous or unjustified pain after ESWL. An ultrasonography or a CT scan confirms the diagnosis. Treatment is conservative in most patients. Mere presence of haematoma is not a contraindication for further ESWL treatments. However, there are instances where angiography, embolization, and even nephrectomy has been required.

Injuries to surrounding organs are very rare. There are stray reports of the injury to the lungs, liver,[8] pancreas[9] and intestine.[10] Injury to the lung is more frequent in children. This can be avoided by the use of styrofoam pads on the chest during ESWL. Even dissection of abdominal aorta[11] has been reported. Renal failure[12] needing dialysis has been reported after bilateral ESWL. In few patients, this has been due to Anti-glomerular basement membrane disease.[13] These injuries are very rare. They are more frequent in patients with uncontrolled diabetes, urinary infections, and coagulopathies. It is important to be aware of these problems and look for them in patients with unexplained symptoms after ESWL.

Steinstrasse, or street of stones is an unusual complication of ESWL, wherein the stone fragments are linked up in the ureter causing obstruction. The patient may be asymptomatic or may present with ureteric colic. This may be prevented to some extent by placing a JJ stent before the procedure.[4] Since this complication is usually associated with larger stone load, it is advisable to place JJ stent in any patient with stone larger than 2 cm. Steinstrasse may be managed by URS or ESWL to the lead fragment. In case of severe obstruction or infection a primary percutaneous nephrostomy would be preferable.

There are few raging controversies about ESWL.

Does ESWL cause hypertension?

There have been many controlled trials on this issue. While Elves et al[14]from Bristol have inferred that ESWL does not cause hypertension, there are other studies like the French study by Bataille P[15] that indicate a link. It is suggested that hypertension after ESWL is frequent in elderly patients and the patients who have renal failure. In practice in patients over 60 years of age and/or with a plasma creatinine of > 3000 micromol/l, ESWL should be performed with caution, and renal function and blood pressure should be carefully monitored.

Does ESWL cause renal functional loss?

ESWL has been found safe in hundreds of clinical trials. It has been found safe in patients of all ages, even in neonates.[16] There are very few studies that suggest a reduction in function after ESWL. It is shown that the resistive index in renal vessels rises after ESWL. This rise is more pronounced in the elderly patients.[17] This may suggest post-ESWL renal damage. In a very interesting physiological study by Eterovic et al[18] it is concluded that ESWL does not achieve substantial improvements in kidney function, which can be achieved by other methods of stone removal.

What are clinically insignificant residual fragments?

Does this entity really exist? Fancy like CIRF have been given to this, but this probably was a result of improper case selection and treatment. Studies with extensive follow-up of these patients showed that only about one-third patients passed these fragments and attained stone free status. About a third of them had increase in the size of these fragments that needed endourological intervention. Candau C[19] et al suggest that the term clinically insignificant residual fragments should not be employed to describe RF after ESWL. Efforts should be performed to obtain true stone-free status after ESWL. Shigeta M et al[20] have performed an interesting study to document the causes of persistence of residual fragments. They examined factors like gender, a history of urolithiasis, the number, location and size of stones and hydronephrosis and found that hydronephrosis highly correlated with persistence of residual fragments after ESWL.

Does ESWL increase the incidence of recurrent calculi?

It was always presumed that ESWL would increase the risk of calculus recurrence. The cause was thought to be persistent small calculus fragments after ESWL. Kosar A et al[21] have analyzed their patients over a follow-up of fourty months and concluded that ESWL does not increase the incidence of recurrent calculi. Recurrence may be higher if ESWL is attempted for larger calculi.

CONCLUSION

ESWL has a proven safety in properly selected patients. Caution is needed in elderly patients or patients with hypertension, diabetes and urinary infection. Any short cuts in investigations and follow-up could be a important cause for ESWL treated complications.

REFERENCES

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2.Fujita K, Mizuno T, Ushiyama T, Suzuki K, Hadano S, Satoh S, Kambayashi T, Mugiya S, Nakano M. Complicating risk factors for pyelonephritis after extracorporeal shock wave lithotripsy. Int J Urol 2000 Jun.; 7 (6) : 224-30.

3.Joshi HB, Obadeyi OO, Rao PN. A comparative analysis of nephrostomy, JJ stent and urgent in situ extracorporeal shock wave lithotripsy for obstructing ureteric stones. BJU Int 1999 Aug.; 84 (3) : 264-9.

4.Al-Awadi KA, Abdul Halim H, Kehinde EO, Al-Tawheed A. Steinstrasse : a comparison of incidence with and without J stenting and the effect of J stenting on subsequent management. BJU Int 1999 Oct.; 84 (6) : 618-21.

5.Salinas AS, Lorenzo-Romero J, Segura M, Calero MR, Hernandez-Millan I, Martinez-Martin M, Virseda JA. Factors determining analgesic and sedative drug requirements during extracorporeal shock wave lithotripsy. Urol Int 1999; 63 (2) : 92-101.

6.Mahmood N, Turner W, Rowgaski K, Almond D. The patients perspective of extracorporeal shock wave lithotripsy. Int Urol Nephrol 1998; 30 (6) : 671-5.

7.Collado Serra A, Huguet Perez J, Monreal Garcia de Vicuna F, Rousaud Baron A, Izquierdo de la Torre F, Vicente Rodriguez J. Renal hematoma as a complication of extra corporeal shock wave lithotripsy. Scand J Urol Nephrol 1999 Jun.; 33 (3) : 171-5.

8. Hirata N, Kushida Y, Ohguri T, Wakasugi S, Kojima T, Fujita R. Hepatic subcapsular hematoma after extracorporeal shock wave lithotripsy (ESWL) for pancreatic stones. J Gastroenterol 1999 Dec.; 34 (6) : 713-6.

9. Abe H, Nisimura T, Osawa S, Miura T, Oka F. Acute pancreatitis caused by extracorporeal shock wave lithotripsy for bilateral renal pelvic calculi. Int J Urol 2000 Feb.; 7 (2) : 65-8.

10. Kurtz V, Muller-Sorg M, Federmann G. Perforation of the small intestine after nephro-uretero-lithotripsy by ESWL- a rare complication. Chirurg 1999 Mar.; 70 (3) : 306-7.

11. Neri E, Capannini G, Diciolla F, Carone E, Tripodi A, Tucci E, Sassi C. Localized dissection and delayed rupture of the abdominal aorta after extracorporeal shock wave lithotripsy. J Vasc Surg 2000 May; 31 (5) : 1052-5.

12. Treglia A, Moscoloni M. Irreversible acute renal failure after bilateral extracorporeal shock wave lithotripsy. J Nephrol 1999 May-Jun.; 12 (3) : 190-2.

13. Iwamoto I, Yonekawa S, Takeda T, Sakaguchi M, Ohno T, Tanaka H, Hasegawa H, Imada A, Horiuchi A, Umekawa T, Kurita T. Anti-glomerular basement membrane nephritis after extracorporeal shock wave lithotripsy. Am J Nephrol 1998; 18 (6) : 534-7.

14.Elves AW, Tilling K, Menezes P, Wills M, Rao PN, Feneley RC. Early observations of the effect of extracorporeal shockwave lithotripsy on blood pressure : a prospective randomized control clinical trial. BJU Int 2000 Apr.; 85 (6) : 611-5.

15.Bataille P, Pruna A, Cardon G, Bouzernidj M, el Esper N, Ghazali A, Westeel PF, Achard JM, Fournier A. Renal and hypertensive complications of extracorporeal lithotripsy. Presse Med 2000 Jan. 15; 29 (1) : 34-8.

16. Lottmann HB, Archambaud F, Traxer O, Mercier-Pageyral B, Helal B. The efficacy and parenchymal consequences of extracorporeal shock wave lithotripsy in infants. BJU Int 2000 Feb.; 85 (3) : 311-5.

17.Aoki Y, Ishitoya S, Okubo K, Okada T, Maekawa S, Maeda H, Arai Y. Changes in resistive index following extracorporeal shock wave lithotripsy. Int J Urol 1999 Oct.; 6 (10) : 483-92.

18.Eterovic D, Juretic-Kuscic L, Capkun V, Dujic Z. Pyelolithotomy improves while extracorporeal lithotripsy impairs kidney function. J Urol 1999 Jan.; 161 (1) : 39-44.

19. Candau C, Saussine C, Lang H, Roy C, Faure F, Jacqmin D. Natural history of residual renal stone fragments after ESWL. Eur Urol 2000 Jan.; 37 (1) : 18-22.

20. Shigeta M, Kasaoka Y, Yasumoto H, Inoue K, Usui T, Hayashi M, Tazuma S. Fate of residual fragments after successful extracorporeal shock wave lithotripsy. Int J Urol 1999 Apr.; 6 (4) : 169-72.

21.Kosar A, Sarica K, Aydos K, Kupeli S, Turkolmez K, Gogus O. Int J Urol 1999 Mar; 6 (3) : 125-9. Comparative study of long-term stone recurrence after extracorporeal shock wave lithotripsy and open stone surgery for kidney stones.



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