British Journal of CJro1og.v (1977), 49, 605-610
0
Partial Nephrectomy for Stone Disease M. B. ROSE
and
0. J. FOLLOWS
Lee& and Bradford Hospitals and Bradford Royal Infirmary
Renal calculi frequently recur after they have been passed or removed, even though no cause for their formation can be found. The rate of recurrence increases the longer patients are observed (Williams, 1963; Blacklock, 1968). The risk of recurrence is not decreased by simple removal of the stone (Williams, 1972). However, it has been claimed that partial nephrectomy does reduce this risk (Stewart, 1960; Papathanassiadis and Swinney, 1966; Hans and Backer, 1972). Recently the operation has been condemned as unsuitable for the majority of renal stones because it involves loss of renal tissue without proven benefit (Anderson, 1974; Marshall et al., 1975). However, there have been very few studies with the necessary prolonged and detailed follow-up after surgery to compare the results of partial nephrectomy with other operations. At Bradford partial nephrectomy was for many years commonly performed for renal calculi. The long-term results of this experience are now reported. Patients and Methods The hospital records of 253 patients who had a partial nephrectomy performed for stone between 1945 and 1973 were obtained from the records of the 2 urological surgeons at the Bradford Royal Infirmary. The patients were asked to attend the hospital. 63 came, 146 failed to come but their hospital records were adequate; 44 patients had inadequate records and were excluded. From the notes of the 209 available patients, details were obtained about preoperative stone incidents and X-rays, operative details and X-rays, and postoperative complications. A stone incident was defined as the spontaneous passage of a stone, its removal or radiological evidence of a stone (Williams, 1963). Ureteric colic alone was not accepted as proof of a stone. Nearly all patients had X-rays taken soon after operation, and any stones shown on the first postoperative films (provided they were taken within a year of surgery) were considered to be residual calculi. The aetiology of all stones was determined from the patient’s history, stone analysis, urine culture, urography and biochemical investigations as recorded in the notes. If no cause for stone formation (apart from hypercalciuria) was found, it was assumed to be idiopathic. The patients who attended hospital were asked about postoperative stone incidents. Plain X-rays of the renal tract were taken, and if suspicious opacities were seen, further films were taken. These were studied (by 0. J. F.) without knowledge of the patient’s history, and a decision made as t o whether stones were present. From the records of patients who did not attend, postoperative stone incidents were diagnosed from the history and X-ray reports. In doubtful cases the films were again reviewed independently. True ipsilateral stone recurrences were defined as those occurring in the operated kidney when postoperative films had shown no residual stones, Stones first seen more than 1 year postoperatively and in the absence of previous films were assumed to be recurrences. True contralateral recurrences were those forming in the unoperated kidney if it was free of stones at the time of partial nephrectomy. Kidneys with residual stones and with contralateral stones present at operation were thus excluded from the calculation of the true recurrence rates, which were defined Read at the 33rd Annual Meeting of the British Association of Urological Surgeons in Aberdeen, June 1977. 605
606
BRITISH JOURNAL OF UROLOGY
Table I
Partial Nephrectomies for Stone : Bradford 1945-73 Number of partial nephrectomies Number of patients
1
2
3
Total
Male Female
135 74
124 69
10 4
1
1
147 80
Total
209
193
14
2
227
Table II
227 Partial Nephrectomies : Indications Small stones Single
Multiple
Large stones
Male Female
57 31
61 25
19 15
Total
94
86
34
Anatomical abnormality and previous stones
Unknown
Total
8 3
2 0
147 80
11
2
227
Table III
227 Partial Nephrectomies : Stone Aetiology Metabolic
Anatomical
Infective
Idiopathic
Total
Male Female
2 7
8 4
10 18
127 51
147 80
Total
9
12
28
178
227
-~
Table IV
227 Partial Nephrectomies: Part of Kidney Removed Side
Pole removed
Right
Left
Upper
106
121
36
Middle Lower 6
Combination
179
6
Table V
227 Partial Nephrectomies: Length of Follow-up Length of follow-up (years) Number of patients
1-5
44
6-10 58
11-15 51
16-20 46
21-25 19
Over26
7
Unknown 2
607
PARTIAL NEPHRECTOMY FOR STONE DISEASE
as the number of kidneys with true recurrences expressed as a percentage of kidneys under surveillance and at risk of recurrences at any given time after operation. In this way an accurate recurrence rate was determined for each year of follow-up.
Results The partial nephrectomies are analysed in Table I ; 12 patients had bilateral operations and 4 kidneys were operated on twice. The patients’ ages at operation ranged from 2 to 76, with a mean of 44 years. Preoperatively 24% of patients had had more than 1 ipsilateral stone incident, and 37 7, 1 or more contralateral incident. The indications for operation are shown in Table 11; large stones were those filling the renal pelvis or occupying more than 1 calyx. Anatomical abnormalities considered to be the site of stone formation were deformed calyces and localised renal calcification. The number of true ipsilateral recurrent stones was not significantly different after operations for single or multiple stones, small or large stones, or for first or recurrent stones. The aetiology of the stones is given in Table 111. Metabolic causes were hyperparathyroidism (5) and cystinuria (4). Anatomical causes were hydronephrosis (4), duplex kidney (2), calyceal cyst (2), medullary sponge kidney (2) and prolonged recumbency (2). All 28 infective stones were associated with persistent urinary infection ; the 15 that were analysed contained magnesium ammonium phosphate. Of the 178 presumed idiopathic stones all the 83 analysed contained calcium oxalate with or without phosphate. 137 patients with these stones had serum calcium estimations; all were normal. The urinary calcium excretion of 96 of these patients was measured, Table VI
227 Partial Nephrectomies : Further Stone Formation Ipsilateral Stone aetiology
Operations
Metabolic Anatomical Infective Idiopathic
9 12 28 178
Total
227
Residual stones
Contralateral
Recurrent stones
2
Stones present at operation
Recurrent stones
3 10
2 2 3 36 (21%)
2 I 1I 36
3 3 2 26 (18%)
16
43 (20%)
50
34 (1 9 %I
1
Percentage recurrences are of kidneys at risk.
Table VII Operative X-rays and Further Stone Formation
Calcification remaining No calcification remaining
Kidneys
Residual stones
True recurrent stones
Mean time to recurrence (years)
Mean follow-up (years)
21 66
6 0
6 8
9.3 14.5
11.0 11.7
608
BRITISH JOURNAL OF UROLOGY
and hypercalciuria (24-hour excretion over 250 mg (6.25 mmol) for males, 200 mg (5 mmol) for females) found in 62. The part of the kidney removed is shown in Table IV. Complications recorded included death in hospital (2 patients), nephrectomy (3 kidneys), secondary haemorrhage (once) and urinary fistula (3 times). The mean follow-up time was 11.9 years from operation, with a range of 1 to 34 years. The distribution is shown in Table V. The total number of residual and true recurrent stones after operation is given in Table VI. Of the 43 ipsilateral recurrent stones, 12 were removed by later operation and 7 passed spontaneously, the other 24 remained in the kidney. For the 34 contralateral recurrences the equivalent numbers were 5, 7 and 22. The results of X-rays of the exposed kidney taken at operation were recorded on 93 occasions. When calcification was still seen at the end of the operation 44 % of these kidneys formed more stones, but when none was seen only 12% did so (Table VII). This difference is statistically significant (P < 0.005). The true recurrence rates of ipsilateral and contralateral stones for each postoperative year are shown in Fig. 1 and Table VIII; the differences between the 2 rates are not statistically significant. In Fig. 2 the true ipsilateral recurrence rate for idiopathic stones alone is compared with the equivalent recurrence rate after other operations for calcium stones (Williams, 1972). At 15 and 20 years there is a statistically significant difference between the rate after partial nephrectomy and that after the other 3 operations (P
0
Partial Nephrectomy for Stone Disease M. B. ROSE
and
0. J. FOLLOWS
Lee& and Bradford Hospitals and Bradford Royal Infirmary
Renal calculi frequently recur after they have been passed or removed, even though no cause for their formation can be found. The rate of recurrence increases the longer patients are observed (Williams, 1963; Blacklock, 1968). The risk of recurrence is not decreased by simple removal of the stone (Williams, 1972). However, it has been claimed that partial nephrectomy does reduce this risk (Stewart, 1960; Papathanassiadis and Swinney, 1966; Hans and Backer, 1972). Recently the operation has been condemned as unsuitable for the majority of renal stones because it involves loss of renal tissue without proven benefit (Anderson, 1974; Marshall et al., 1975). However, there have been very few studies with the necessary prolonged and detailed follow-up after surgery to compare the results of partial nephrectomy with other operations. At Bradford partial nephrectomy was for many years commonly performed for renal calculi. The long-term results of this experience are now reported. Patients and Methods The hospital records of 253 patients who had a partial nephrectomy performed for stone between 1945 and 1973 were obtained from the records of the 2 urological surgeons at the Bradford Royal Infirmary. The patients were asked to attend the hospital. 63 came, 146 failed to come but their hospital records were adequate; 44 patients had inadequate records and were excluded. From the notes of the 209 available patients, details were obtained about preoperative stone incidents and X-rays, operative details and X-rays, and postoperative complications. A stone incident was defined as the spontaneous passage of a stone, its removal or radiological evidence of a stone (Williams, 1963). Ureteric colic alone was not accepted as proof of a stone. Nearly all patients had X-rays taken soon after operation, and any stones shown on the first postoperative films (provided they were taken within a year of surgery) were considered to be residual calculi. The aetiology of all stones was determined from the patient’s history, stone analysis, urine culture, urography and biochemical investigations as recorded in the notes. If no cause for stone formation (apart from hypercalciuria) was found, it was assumed to be idiopathic. The patients who attended hospital were asked about postoperative stone incidents. Plain X-rays of the renal tract were taken, and if suspicious opacities were seen, further films were taken. These were studied (by 0. J. F.) without knowledge of the patient’s history, and a decision made as t o whether stones were present. From the records of patients who did not attend, postoperative stone incidents were diagnosed from the history and X-ray reports. In doubtful cases the films were again reviewed independently. True ipsilateral stone recurrences were defined as those occurring in the operated kidney when postoperative films had shown no residual stones, Stones first seen more than 1 year postoperatively and in the absence of previous films were assumed to be recurrences. True contralateral recurrences were those forming in the unoperated kidney if it was free of stones at the time of partial nephrectomy. Kidneys with residual stones and with contralateral stones present at operation were thus excluded from the calculation of the true recurrence rates, which were defined Read at the 33rd Annual Meeting of the British Association of Urological Surgeons in Aberdeen, June 1977. 605
606
BRITISH JOURNAL OF UROLOGY
Table I
Partial Nephrectomies for Stone : Bradford 1945-73 Number of partial nephrectomies Number of patients
1
2
3
Total
Male Female
135 74
124 69
10 4
1
1
147 80
Total
209
193
14
2
227
Table II
227 Partial Nephrectomies : Indications Small stones Single
Multiple
Large stones
Male Female
57 31
61 25
19 15
Total
94
86
34
Anatomical abnormality and previous stones
Unknown
Total
8 3
2 0
147 80
11
2
227
Table III
227 Partial Nephrectomies : Stone Aetiology Metabolic
Anatomical
Infective
Idiopathic
Total
Male Female
2 7
8 4
10 18
127 51
147 80
Total
9
12
28
178
227
-~
Table IV
227 Partial Nephrectomies: Part of Kidney Removed Side
Pole removed
Right
Left
Upper
106
121
36
Middle Lower 6
Combination
179
6
Table V
227 Partial Nephrectomies: Length of Follow-up Length of follow-up (years) Number of patients
1-5
44
6-10 58
11-15 51
16-20 46
21-25 19
Over26
7
Unknown 2
607
PARTIAL NEPHRECTOMY FOR STONE DISEASE
as the number of kidneys with true recurrences expressed as a percentage of kidneys under surveillance and at risk of recurrences at any given time after operation. In this way an accurate recurrence rate was determined for each year of follow-up.
Results The partial nephrectomies are analysed in Table I ; 12 patients had bilateral operations and 4 kidneys were operated on twice. The patients’ ages at operation ranged from 2 to 76, with a mean of 44 years. Preoperatively 24% of patients had had more than 1 ipsilateral stone incident, and 37 7, 1 or more contralateral incident. The indications for operation are shown in Table 11; large stones were those filling the renal pelvis or occupying more than 1 calyx. Anatomical abnormalities considered to be the site of stone formation were deformed calyces and localised renal calcification. The number of true ipsilateral recurrent stones was not significantly different after operations for single or multiple stones, small or large stones, or for first or recurrent stones. The aetiology of the stones is given in Table 111. Metabolic causes were hyperparathyroidism (5) and cystinuria (4). Anatomical causes were hydronephrosis (4), duplex kidney (2), calyceal cyst (2), medullary sponge kidney (2) and prolonged recumbency (2). All 28 infective stones were associated with persistent urinary infection ; the 15 that were analysed contained magnesium ammonium phosphate. Of the 178 presumed idiopathic stones all the 83 analysed contained calcium oxalate with or without phosphate. 137 patients with these stones had serum calcium estimations; all were normal. The urinary calcium excretion of 96 of these patients was measured, Table VI
227 Partial Nephrectomies : Further Stone Formation Ipsilateral Stone aetiology
Operations
Metabolic Anatomical Infective Idiopathic
9 12 28 178
Total
227
Residual stones
Contralateral
Recurrent stones
2
Stones present at operation
Recurrent stones
3 10
2 2 3 36 (21%)
2 I 1I 36
3 3 2 26 (18%)
16
43 (20%)
50
34 (1 9 %I
1
Percentage recurrences are of kidneys at risk.
Table VII Operative X-rays and Further Stone Formation
Calcification remaining No calcification remaining
Kidneys
Residual stones
True recurrent stones
Mean time to recurrence (years)
Mean follow-up (years)
21 66
6 0
6 8
9.3 14.5
11.0 11.7
608
BRITISH JOURNAL OF UROLOGY
and hypercalciuria (24-hour excretion over 250 mg (6.25 mmol) for males, 200 mg (5 mmol) for females) found in 62. The part of the kidney removed is shown in Table IV. Complications recorded included death in hospital (2 patients), nephrectomy (3 kidneys), secondary haemorrhage (once) and urinary fistula (3 times). The mean follow-up time was 11.9 years from operation, with a range of 1 to 34 years. The distribution is shown in Table V. The total number of residual and true recurrent stones after operation is given in Table VI. Of the 43 ipsilateral recurrent stones, 12 were removed by later operation and 7 passed spontaneously, the other 24 remained in the kidney. For the 34 contralateral recurrences the equivalent numbers were 5, 7 and 22. The results of X-rays of the exposed kidney taken at operation were recorded on 93 occasions. When calcification was still seen at the end of the operation 44 % of these kidneys formed more stones, but when none was seen only 12% did so (Table VII). This difference is statistically significant (P < 0.005). The true recurrence rates of ipsilateral and contralateral stones for each postoperative year are shown in Fig. 1 and Table VIII; the differences between the 2 rates are not statistically significant. In Fig. 2 the true ipsilateral recurrence rate for idiopathic stones alone is compared with the equivalent recurrence rate after other operations for calcium stones (Williams, 1972). At 15 and 20 years there is a statistically significant difference between the rate after partial nephrectomy and that after the other 3 operations (P
