0022-5347 /91/1453-04 77$03.00/0 VoL 145, 477-480, March 1991

'THE JOURNA:. 05 UROLOGY

Copyright© 1991 by AMERICAN UROLOGICAL ASSOCIATION,

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PERCUTANEOUS NEPHROLITHOTOivIY AND THE SOLITARY KIDNEY DAVID J. JONES,* MICHAEL J. KELLETT

AND

JOHN E. A. WICKHAM

From the Institute of Urology and St. Paul's Hospital, London, England

ABSTRACT

We reviewed 53 patients with stones in a solitary kidney who had undergone percutaneous nephrolithotomy. Previous surgery on that kidney had been performed in 35.8%, and 50.9% had other medical conditions including 26.4 % who had impaired renal function. Staghorn or partial staghorn calculi were present in 52.9% and an additional 18.8% had multiple stones. Postoperative complications in 18.8% of the patients included sepsis, the need for transfusion and 1 death of bronchopneumonia. Percutaneous nephrolithotomy alone resulted in a 77.3% rate free of stone or fragments of 2 mm. or less. This rate increased to 86.8% with the addition of extracorporeal shock wave lithotripsy, ureteroscopy or open surgery (2 patients). Only 1 patient suffered long-term deterioration in renal function. Percutaneous nephrolithotomy is a safe procedure in the solitary kidney. It should be considered in those patients with complex stone burdens and impaired renal function when reduction in stone bulk and improved renal function may allow other treatment modalities to be used. KEY

WORDS: kidney calculi, lithotripsy

Percutaneous nephrolithotomy is now a well established and effective method of treating renal stones with success rates of greater than 90% reported. 1 Even in patients with multiple medical problems and complex stone burdens it is possible to achieve success rates of 83% especially when other treatment modalities, such as extracorporeal shock wave lithotripsy (ESWLt) and ureteroscopy, are used. 2 There has been little reported about the use of percutaneous nephrolithotomy in kidneys that are congenitally solitary or solitary as a result of surgery, stones or infection affecting the opposite kidney. An early series of percutaneous nephrolithotomy reported from Germany included 14 of 54 patients with a solitary kidney but this subgroup was not analyzed further. 3 The largest American series of 1,000 cases included 15 patients with solitary kidneys whose postoperative renal function did not differ from the entire group. 1 Other percutaneous nephrolithotomy series mention occasional cases of solitary kidney but they are not analyzed to determine whether such patients fare better or worse due to the lack of a contralateral kidney contributing to over-all renal function. Before the advent of percutaneous nephrolithotomy, the effect of hypothermic nephrolithotomy on solitary kidneys was studied by some 4 - 6 and it was recognized that the use of intravenous inosine further protected the kidney during ischemic nephrolithotomy. 7 Indeed, in patients with already severely compromised renal function open nephrolithotomy and reduction in stone burden may result in improvement in renal function and save patients from dialysis. 8 To document the results of percutaneous nephrolithotomy in the solitary kidney and to determine how this therapy affected renal function we reviewed such patients who had undergone percutaneous nephrolithotomy at our hospital. PATIENTS AND METHODS

All patients undergoing percutaneous nephrolithotomy for stones in solitary kidneys at St. Paul's Hospital between 1981 and 1988 were reviewed. The term solitary kidney was used for patients with a congenitally solitary kidney, those who had undergone previous nephrectomy and those with a nonfunctioning kidney or a kidney that was shown to be contributing Accepted for publication July 24, 1990. * Requests for reprints: Gloucestershire Royal Hospital, Great Western Rd., Gloucester GLl 3NN, England. t Dornier Medical Systems, Inc., Marietta, Georgia. 477

5% or less to over-all renal function on 99 mtechnetium dimercaptosuccinic acid (DMSA) isotope renography. The technique of percutaneous nephrolithotomy was a standard 1-stage procedure, except some of the early patients underwent a 2-stage procedure. 9 Percutaneous nephrolithotomy was performed with the patient under general anesthesia with perioperative antibiotic coverage and the placement of a retrograde ureteral catheter when possible. Stones or fragments were removed with alligator or triradiate forceps and stone disintegration was performed with ultrasound or electrohydraulic lithotripsy. Preoperative assessment included history, physical examination, urine culture, complete blood count, electrolyte, urea and creatinine estimation, excretory urography (IVP) and DMSA renography. In the immediate postoperative period renal function was assessed with serial electrolyte, urea and creatinine measurements. A plain abdominal x-ray was taken at 48 hours. When nephrostomy drainage was necessary a nephrostogram was performed and if satisfactory the tube was removed. Long-term followup included renal function measurements, plain x-ray and DMSA renography when indicated. Those patients with poor preoperative renal function were managed in consultation with nephrologists. The results reported for stone clearance or eventual renal function are those available at the last followup review or at the time of discharge of the patient from our care. RESULTS

Between 1981 and 1988, 1,000 patients underwent percutaneous nephrolithotomy at our hospital, of whom 53 had a solitary kidney as previously defined. The kidney was on the left side in 30 and on the right side in 23 patients. There were 24 men and 29 women, with an age range of 17 to 82 years (mean 50.9). Of the patients 19 (35.8%) had undergone previous surgery on the solitary kidney and medical problems were present in 27 (50.9%) (table 1). Causes of the solitary kidney are shown in table 2. It should be noted that stone disease accounted for loss of the other kidney, or its poor function or nonfunction in 33 patients (62.3%). There were 14 patients with abnormal renal function at presentation. Details of the preoperative and postoperative creatinine levels are shown in table 3. Solitary stones were present in 15 patients, including 10 stones 10 mm. or greater in diameter. More complex stones were present in the remaining 38 patients (71.7%), including

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JONES, KELLETT AND WICKHAM

1. Medical problems in 27 patients undergoing percutaneous

TABLE

nephrolithotomy on a solitary kidney No. Pts. 14 4

Impaired renal function Ilea! conduit Ileostomy (extensive Crohn's disease) Cysteinuria Idiopathic hypercalciuria Medullary sponge kidney Renal tubular acidosis Nephrostomy since 1955 (no ureter, tuberculosis) Hyperparathyroidism Severe ischemic heart disease Severe hypertension Hypertension and renal artery stenosis Severe respiratory disease Total

2 5 2

1 1 1 1 1 1 1

1 35*

* Some patients had more than 1 medical problem.

TABLE

2. Causes of solitary, nonfunctioning or poorly functioning

kidney No. Pts. Congenital Nephrectomy due to stones Nephrectomy following pyonephrosis and stones Nephrectomy due to ureteropelvic junction obstruction Nephrectomy due to tuberculosis Nephrectomy for xanthogranulomatous pyelonephritis Poor function or nonfunction due to stones Poor function or nonfunction due to pyelonephritis or old reflux Total

TABLE

6

11 8

4 3

1 14 6

53

3. Results in 14 patients with impaired preoperative renal

function Pt. No.

Creatinine (µmo!./ I., normal range 60-120) Preop.

Postop.

1

287

550

2 3 4 5

323 545 240 585

134 330 215 420

6 7 8 9 10

205 235 237 295 870

185 160 205 205 140

11 12 13 14

365 265 330 726

220 195 310 500

TABLE

Comments

Matrix staghorn Pyonephrosis, 82 yrs. old, died of bronchopneumonia Ilea! conduit, spina bifida Complete staghorn Ilea! conduit, spina bifida Ring nephrostomy, no ureter, tuberculosis Renal tubular acidosis Matrix staghorn Hyperparathyroid, obstructing stone, emergency percutaneous nephrostomy Complete staghorn Partial staghorn Medullary sponge kidney

4. Results after percutaneous nephrolithotomy alone and with

other treatment modalities in 53 patients

After Percutaneous N ephrolithotomy No.(%)

Free of stone Fragments ;e,2 mm. Total% Fragments >2 mm.

20 (37.7) 21 (39.6) 77.3 12 (22.7)

After Percutaneous Nephrolithotomy and Other Procedures No.(%) 29 (54.7) 17 (32.1) 86.8 7 (13.2)

multiple stones in 10, partial staghorns in 9 and complete staghorns in 19. More than 1 access tract was necessary in 15 patients (28.3%). The stones were extracted intact in 8 patients with the remainder (85%) requiring ultrasound or electrohy-

draulic lithotripsy. Nephrostomy drainage was used in 33 patients (62.3% ). Perioperative problems were minimal and included a high ureteral calculus that could not be pushed in 3 patients, an unexpected pyonephrosis in 1, perforation of the renal pelvis in 2 and heavy bleeding in 1. Postoperative complications were seen in 10 patients (18.8%). Blood transfusion was necessary in 6 patients (1 to 2 units, mean 1.8), pyrexia requiring antibiotics was seen in 4, and severe ureteral colic, postoperative confusion and a urethral stricture were seen in 1 patient. There was 1 death of an 82-year-old woman who died of renal failure and bronchopneumonia. More than 1 attempt at percutaneous nephrolithotomy was necessary in 10 patients with 1 requiring 3 and 1 requiring 4 sessions. Other forms of treatment were used in 9 patients (17%). ESWL was performed in 7 patients with 1 requiring ultrasound and basket retrieval of a ureteral fragment. Another 2 patients who underwent ESWL required ultrasound and subsequently open surgery (1 pyelolithotomy and 1 ureterolithotomy). Followup varied from 2 to 31 months (mean 12.7). The results with regard to stone clearance after percutaneous nephrolithotomy alone and after addition of other treatments are shown in table 4. Of the 20 patients in whom nephrostomy drainage was deemed unnecessary 14 were free of stone at a followup of between 4 and 29 months. In 4 patients who were thought to be free of stone at the conclusion of percutaneous nephrolithotomy small fragments remained, which were successfully treated by ESWL. In 1 patient with poor renal function a fragment less than 2 mm. was noted in a parallel calix to the initial puncture. We decided to leave this stone in situ and at 16-month followup it remains the same size and causes no symptoms. The remaining patient had a complex staghorn and presented with acute and chronic renal failure. Initial percutaneous needle nephrostomy to establish drainage was only partially successful and, therefore, percutaneous nephrolithotomy was performed leaving multiple fragments that are being treated by ESWL. Stone analysis was available in 46 cases (86.8%). Mixed triple phosphate and calcium phosphate stones were found in 35 patients, calcium oxalate in 6 and cysteine stones in 5. DISCUSSION

To our knowledge this is the largest series of patients with solitary kidneys who have undergone percutaneous nephrolithotomy and the only study to address the issue of performing this therapy and other procedures in the solitary kidney, although previous reports have noted the effects of open surgery in such patients. 4- 6 Many surgeons are wary of the use of a "blind" technique such as percutaneous nephrolithotomy for stone removal in the solitary kidney. The reason for their skepticism is the risk of damage to the kidney or severe hem orrhage necessitating embolization or partial nephrectomy with further loss of functioning renal parenchyma. Instead most surgeons prefer the more controlled milieu of open surgery in the ischemic kidney using inosine or hypothermia. In fact uncontrolled bleeding after percutaneous nephrolithotomy requiring angiographic embolization has developed in few patients, with only 6 (0.6%) reported in a recent review of 1,000 patients from our hospital, none of whom required nephrectomy for complications of the procedure. 2 Other large series have similarly reported low incidences of such complications. 1• 10 It has been shown that damage to the renal parenchyma by a serially dilated percutaneous nephrostomy tract results in only a small linear scar 11 and that the effects on renal function from percutaneous nephrolithotomy are minimal. 12 Even open surgery, if careful techniques such as the extended sinus approach and radial nephrostomy are used, will cause little functional or parenchymal loss.13 A large number of our patients had other medical problems (50.9%), including more than 26 % with impaired renal function.

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In such patients, who often have large and infected stone burdens, many factors in addition to percutaneous nephrolithotomy will contribute to the eventual outcome. The patients with impaired renal function did surprisingly well as a group, and the results confirm that operative intervention is worthwhile in terms of improved renal function and reduced stone burden. The statement that, "one should temper obsessive attempts at clearance of small fragments with caution in the kidney with severely damaged function" is equally true for percutaneous nephrolithotomy as it is for open surgery. 8 We have found it preferable to abandon lengthy percutaneous nephrolithotomy sessions in kidneys with large stone burdens and to perform 1 or more repeat procedures rather than submit these often ill patients to the complications of a prolonged anesthetic, transurethral resection type syndromes and other postoperative problems. It is equally important that preoperative preparation of these patients is meticulous and that there is close collaboration with nephrologists. The availability of acute dialysis facilities is essential. The only death occurred in this subgroup and, in retrospect, this elderly patient was too ill to undergo any procedure. More than 60% of the patients had lost the other kidney because of stone disease. Therefore, it was important to pursue an active treatment policy for stones in the remaining kidney. The low incidence of patients with congenitally solitary kidneys seems to confirm that these patients generally suffer no impairment to life because of the healthy solitary kidney. The stone burden in these patients was high with 72% having multiple or staghorn calculi, compared to our incidence of 38. 7% in all patients undergoing percutaneous nephrolithotomy. There have been no problems with access and minimal perioperative problems. A postoperative complication rate of 19% is similar to that of 18.8% experienced in our review of 1,000 patients recently reported. 2 Except for the single death, only 1 complication, a urethral stricture, led to long-term problems. More than 77% of the patients were rendered free of stone or had fragments of 2 mm. or less. With the addition of other treatment modalities this rate increased to 86.8%. These figures are lower than the best quoted from other series but it must be stressed that they reflect a desire to preserve renal parenchyma, often at the expense of leaving stone fragments in situ. It is important to realize that with the availability of many methods of stone removal that are noninvasive or relatively noninvasive, the preservation or improvement in renal function is paramount. It could be argued that by omitting nephrostomy drainage after primary percutaneous nephrolithotomy in all patients, those with residual fragments would require a repeat session or other form of therapy to treat the remaining stones satisfactorily. In fact, of 20 patients who did not have nephrostomy drainage only 4 had unsuspected residual stones that were easily treated ESWL. Thus, it seems that the discomfort and inconvenience of a nephrostomy tube postoperatively can be avoided in some patients on the basis of clinical judgment aloneo We conclude that in experienced hands the use of percutaneous nephrolithotomy for calculi in solitary kidneys is safe and effective. Complication rates are acceptably low and, with the addition of ESWL and ultrasound, the objectives of preservation of renal function and reduced stone burden even in patients with substantially impaired renal function can be achieved. Ms. Margaret Gay and Sarah Reed provided assistance in the preparation of this report. REFERENCES

1. Segura, J. W., Patterson, D. E., LeRoy, A. J., Williams, H.J., Jr., Barrett, D. M., Benson, R. C., Jr., May, G. R. and Bender, C. E.: Percutaneous removal of kidney stones: a review of 1,000 cases. J. Urol., 134: 1077, 1985.

2. Jones, D. Jo, Russell, G. L., Kellett, Mo J. and Wickham, J. E. A.: The changing practice of percutaneous stone surgery: a review of 1,000 cases 1981-1988. Brit. J. Urol., 66: 1, 1990. 3. Alken, P., Hutschenreiter, G., Gunther, R. and Marberger, M.: Percutaneous stone manipulation. J. Urol., 125: 463, 1981. 4. Perry, N. M., Wickham, J.E. A. and Whitfield, H. N.: Hypothermic nephrolithotomy in solitary kidneys. Brit. J. Urol., 52: 415, 1980. 5. Redman, J. F. and Bissada, N. K.: Extensive nephrolithotomy in previously operated solitary kidneys. J. Urol., 115: 502, 1976. 6. Stubbs, A. J., Resnick, M. I. and Boyce, W. H.: Anatrophic nephrolithotomy in the solitary kidney. J. Urol., 119: 457, 1978. 7. Wickham, J.E. A., Fernando, A. R., Hendry, W. F., Whitfield, H. N. and Fitzpatrick, J. M.: Intravenous inosine for ischaemic renal surgery. Brit. J. Urol., 51: 437, 1979. 8. Witherow, R. 0. and Wickham, J. E. A.: Nephrolithotomy in chronic renal failure: saved from dialysis! Brit. J. Urol., 52: 419, 1980. 9. Wickham, J. E. A., Miller, R. A., Kellett, M. J. and Payne, S. R.: Percutaneous nephrolithotomy: one stage or two? Brit. J. Urol., 56: 582, 1984. 10. Lee, W. J., Smith, A. D., Cubelli, V. and Vernace, F. M.: Percutaneous nephrolithotomy: analysis of 500 consecutive cases. Urol. Rad., 8: 61, 1986. 11. Webb, D. R. and Fitzpatrick, J. M.: Percutaneous nephrolithotripsy: a functional and morphological study. J. Urol., 134: 587, 1985. 12. Tasca, A., D'Angelo, A., Zattoni, F., Ferrarese, P., Calo, L., Bui, F. and Cagnato, P.: Short-term and stabilized effects of percutaneous nephrolithotomy on the kidney. Eur. Urol., 14: 120, 1988. 13. Fitzpatrick, J.M., Sleight, M. W., Braack, A., Marberger, M. and Wickham, J. E. A.: Intrarenal access: effects on renal function and morphology. Brit. J. Urol., 52: 409, 1980.

EDITORIAL COMMENTS Knowledge that a given kidney is solitary certainly "focuses one's attention" on the procedure at hand and the results in this series should be comforting to the endourologist. This is the largest series reporting the results of percutaneous nephrolithotomy in solitary kidneys, and it is particularly useful in its demonstration of the success of percutaneous nephrolithotomy in a group of patients unprotected by a contralateral kidney and further supports the use of percutaneous techniques in patients with 2 normal kidneys. The indications for percutaneous lithotripsy have changed considerably during the period represented in this study. In the last few years percutaneous lithotripsy has been used mainly in complicated situations and for large stones. A number of points made in the series are worth repeating. Although there is no substitute for a state free of stone, particularly if the stone is infected, the price of achieving this goal should not be damage to the kidney. A given stone may require more than 1 session for removal, especially if the stone is large. This second session is almost always easier than the first, because of lack of bleeding and because the urologist is working through a matured tract. I disagree that there are occasional patients in whom a nephrostomy tube is not necessary. While it is true that an inadvertent residual stone can be treated with shock wave lithotripsy, it can be removed more easily through the matured tract and I am convinced that nephrostomy tube drainage minimizes postoperative perinephric bleeding. Percutaneous procedures continue to be safe and useful in the shock wave world, particularly in complicated situations, and their availability will ensure optimum treatment of stone patients. Joseph W. Segura

Mayo Clinic Rochester, Minnesota This study demonstrates convincingly that in the hands of those experienced in endourology percutaneous nephrolithotomy is a safe technique in patients with a solitary renal unit. As the authors clearly state the complications associated with percutaneous nephrolithotomy in this group of patients are no higher than in patients with 2 functioning renal units. Nonetheless, the decision not to leave a nephrostomy tube indwelling following percutaneous nephrolithotomy in 14 patients is needlessly daring. Animal studies suggest that nonuse of a nephrostomy tube is associated with significant risk of hemorrhage from the nephrostomy site. 1 Additionally, the nephrostomy tube en-