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Partial nephrectomy in surgical treatment of calculous disease
SCIIENTIFIC ARTICLES
PARTIAL NEPHRECTOMY TREATMENT
IN SURGICAL
OF CALCULOUS
DISEASE
URI WALD, M.D. MARCO CAINE,
M.S., F.R.C.S.
HARVEY SOLOMON,
M.D.
From the Department of Urology, Hadassah University Hospital, Jerusalem, Israel
ABSTRACT - Of a total of 158 partial nephrectomies, a detailed follow-up for up to sixteen years was obtained in 131. The rate of true ipsilateral recurrences was 26 per cent. Computer analysis of various parameters indicated that a previous history of a stone in the same or the contralateral kidney, or the presence of multiple or scattered stones in the affected side, were associated with a particularly high recurrence rate. Urinary infection at the time of or prior to operation was not of prognostic signijcance. The importance of complete excision of the calyceal neck was confirmed. It was concluded that the operation is logical for removal of a diseased segment of kidney, but generally cannot be recommended in the hope of removing a stone-bearing area of kidney and hence reducing the recurrence rate.
It has been widely accepted for many years that the operation of choice in many cases of renal calculi, particularly those involving a calyx or calyces, is partial nephrectomy. This has been based on the belief that this operation greatly reduces the likelihood of a true recurrence of stone in the operated kidney, and hence fully justifies any possible slight increase in operative or postoperative complications as compared with pyelolithotomy or even nephrolithotomy. The validity of this belief has been put in doubt by two reports from Scandinavia, that of Pedersenl reporting a recurrence rate of 20.6 per cent in 150 operations followed up for a mean of 3.9 years, and that of Myrvold and Fritjoffson2 in which a recurrence rate of 43 per cent in 65 patients followed up for a mean of 9 years, was reported. These and many other recent authors have stressed the paramount importance of a long follow-up when attempting to assess the recurrence rate of renal calculi, whether after operation or after spontaneous passage. Marshall et al., 3 for example, have pointed out that recurrence may take place more than ten years
338
after a previous stone, and in Williams’4 series the average time taken for an ipsilateral recurrence (not necessarily after operation) was 8.4 years. Another point that is considerably clear is that many recurrent calculi may be entirely silent, at any rate for a prolonged period, and thus any figures for recurrence that are not based on a follow-up including roentgenography are liable to be fallacious. Owing to the very high incidence of renal calculi in our population, we have obtained a relatively large experience with this operation in our department; therefore, we decided to carry out a long-term follow-up of our cases to determine whether our late results supported the belief that we were greatly reducing the recurrence rate or whether, perhaps, they corresponded to those authors who found a disturbingly high recurrence rate. In addition, we hoped to be able to analyze the various parameters in relationship to recurrence to identify any factors that could be recognized as being significantly related to it, and hence perhaps more precisely to define the indications for this operation.
UROLOGY
/ APRIL 1978 / VOLUME
XI, NUMBER 4
No.
10
20
30
40
50
60
70
80
nws
Age distribution of patients with partial
FIGURE 1.
nephrectomy.
clamp was used on the pedicle, and hemostasis was obtained by direct suturing of the individual vessels on the cut surface with 4-O catgut. The pelvicalyceal opening was closed with continuous 3-O catgut. The ischemic time, which was recorded in all cases by the anesthetist, was rarely more than twenty minutes, and it was never found necessary to use local cooling of the kidney. Some of our staff reflected the capsule and used it to cover the cut surface, buttonholing it to prevent hematoma formation, and others did not leave any capsule. One can record that there was no difference in any parameters examined via the computer between these two methods.
Material and Method
Results
We have reviewed the cases of partial nephrectomy performed in our department during the years 1960 to 1976 inclusive. All the patients were invited for a personal interview, at which time in addition to an updating history and physical examination, a midstream specimen of urine was examined and cultured, blood chemistry checked, and an x-ray film taken. In those patients in whom a satisfactory postoperative IVP had already been obtained, only a plain film was taken in the first instance on the follow-up examination, the IVP being repeated if there was any suggestion of a recurrence. If no postoperative IVP had been taken, this was done on the occasion of the follow-up. All our patients with calculi have a routine plain roentgenogram performed before leaving the hospital, so we had evidence as to the presence or absence of any residual stones, the so-called “false” recurrences. All relevant data were extracted from the patient’s hospital records, and the old x-ray films were reviewed to determine details of the number and distribution of the stones, the functional and anatomic condition of the kidney before operation, and so forth. All the information obtained from the past records, follow-up examination, and roentgenograms past and present, was suitably coded and analyzed with the aid of a computer, thus enabling us to examine and identify any interrelationships between the various parameters recorded. The operations were performed by the residents or senior staff of our department, and the technique used was practically standardized. All our cases were performed by a “guillotine” section across the kidney using a scalpel, and none was done by a wedge resection. A soft
UROLOGY
/ APRIL1978 / VOLUMEXI,
NUMBER4
A total of 158 partial nephrectomies on 151 patients was performed in the period reviewed. In 5 patients the operations were bilateral, and in 2 patients two separate partial nephrectomies were performed on the same kidney. In 8 patients the operations were performed on a solitary kidney. There were 94 males and 57 females in the series, and the ages ranged from eleven to seventy-eight years (Fig. 1). The complications encountered in the 158 operations performed are listed in Table I, and are found to compare favorably with those in other published series. A satisfactory follow-up was obtained on 131 operations up to sixteen years, with a mean follow-up time of 5.85 years. Among these we found a total of 34 true ipsilateral recurrences, or an incidence of 26 per cent. The question arises as to whether or not the fact that this country has an extremely high incidence of urinary tract calculi (1.18 per cent of all the population according to Frank et al.)” results in an increased likelihood of recurrence after operation as compared with countries with an over-all lower incidence of calculi. An indication of this is afforded by the recurrence rate
TABLE
I.
Operative complications in 158 operations
Complications Death Secondary hemorrhage Fistula for more than ten days Wound dehiscence Secondary nephrectomy Closure of fistula
Number 1
3 1
4 2 1
339
TABLE II.
Previous history of ipsilateral
Calculus None Previous stone
Number
Recurrences
TABLE III.
Previous history of contralateral calculus
History
Number
Per Cent
16
20.3
34.6
Distribution
of calculi in kidney
Calculi
Number
Recurrences
TOTALS
26
Per Cent
2 0 0
50 0 0 - 18
4
15
2
61.5 1
TABLE V.
Recurrences
51
25
2
TABLE IV.
4 7 4 11
39
16
Not known P = 0.001: highly significant
18
10
9 49
Unilateral only 79 Presence or history of contralateral 52 P = 0.02: significant
Per Cent
8
80 Passed, 23 Operated, 26
Solitary Pelvis Lower calyx Upper calyx Stagbom
calculus
Infection
50
Relationship of urinary infection to recurrence Number
Recurrences
Per Cent
Before operation 69 Yes 58 No 4 Not known P = 0.5: not significant
19 13 2
27.5 22.4 50
At operation 63 Yes 68 No Not known 0 P = 0.4: not significant
20 14 0
31.7 20.6 0
At follow-up Yes 65 62 No 4 Not known P = 0.05: significant
25 8 1
38.5 12.9 25
of 118
possible relationships to recurrences, and from these the following results of importance have emerged. The history of a previous stone in the same kidney was found to be associated with an approximately fivefold increase in the likelihood of recurrence, a statistically highly significant result, and this was apparently even greater if that stone had had to be removed by a previous operation (Table II). Although not so
such patients followed up from our department by Gertler,6 33 true recurrences were found, or an incidence of 28 per cent. This is well within the generally accepted range of recurrence after pyelolithotomy and does not suggest an exaggerated tendency to recurrence in our population. This was a comparable group to our present series of partial nephrectomies. It had a follow-up extending also up to sixteen years, with a mean follow-up time of 5.3 years. The close relationship of the two recurrence rates, 28 per cent and 26 per cent, is therefore striking and significant. A large number of parameters were investigated with the aid of the computer for their
impressive, there is also statistically significant evidence of an increased likelihood of recurrence if a contralateral stone is present at the time of operation or had been present in the past (Table III). The relationship between the number and distribution of the stones in the operated kidney and the recurrence rate is summarized in Table IV. In view of the disparity in the numbers, the results here are statistically not of significance. However, if the trend of the figures was to be maintained in larger groups, it would appear that multiple calculi are more likely to recur than solitary ones, and those scattered throughout the kidney more so than multiple calculi confined to a
Multiple Single calyx + pelvis Scattered TOTALS
after simple
340
81 24
19 _ll_
23.5 j5.8_
105
30
28.6
pyelolithotomy.
In a series
UROLOGY / APRIL 1978 I VOLUMEXI, NUMBER4
TABLE VI.
Composition Phosphate stones Others
Total 23 108
Relationship of stone composition to infection and recurrence
Infected at or Before Operation
Not Infected
Recurrences
17 (74)* 77 (71)
6 (26) 31 (29)
8 (34.8) 26 (24 )
*Figuresin parenthesessignifyper cent.
solitary calyx. with or without an associated calculus in the renal pelvis. The question of the relationship of recurrence to urinary infection is of interest. There was no correlation between the recurrence rate and the presence of urinary infection prior to operation (Table V), nor was the apparent correlation with urinary infection at the time of operation of statistical significance (Table V). The same conclusion was reached by Myrvold and Fritjoffson2 and by Williams4 in their series. A relationship did appear to exist between recurrent stone formation and infection at the follow-up examination (Table V). However, whether or not this is causally related to the new stone formation or is the result of the presence of the stone is not clear. Separation of the group of phosphate stones, which may be considered to be more likely associated with infection, from other stones did not show any appreciable difference (Table VI). Despite these negative findings regarding infection, an examination of the resected part of the kidney did appear to indicate a relationship between the condition of the renal tissue and the risk of recurrence (Table VII). The proportion of normal to pathologic specimens is similar to that in Pedersen’s’ and in Myrvold and Fritjoffson’s’ series. The problem here is the interpretation of the pathologic changes. It appears clear these days that the so-called pyelonephritic changes do not necessarily imply an infective lesion and may simply indicate a nonspecific reaction to the irritation produced by the stone. Thus, these results are not necessarily in conflict with those relating to infection. An attempt was made to determine if there was any difference in the recurrence rates between the kidneys in which the dilated or deformed calyces were caused by the contained stone, or those in which such calyces were produced secondarily by obstruction by a stone elsewhere, or by a primary hydronephrosis
UROLOGY / APRIL1978 / VOLUMEXI, NUMBER4
TABLE VII.
Pathology of excised tissue
Number Recurrences Per Cent
Pathology Normal Pathologic N~~;,$oJophritic”)
25
0
0
99 7 P = 0.041: significant
32 2
32.3 28.6
TABLE VIII.
Condition of kidney at operation
Conditions
Number
Recurrences Per Cent
Dilatation or deformity of calyx due to contained stone(s) 84
24
28.6
Dilatation of calyx secondary to obstruction by stone
47
18
38.3
6
2
33.3
Primary hydronephrosis with secondary stones
(Table VIII). Those in the latter groups would be more likely to return to normal after removal of the obstructing stone or after plastic correction of the hydronephrosis, which was performed together with the partial nephrectomy when indicated. Here as the conditions are not mutually exclusive, the sums of the numbers exceed the total number of cases and recurrences. As can be seen, there is no significant difference between these groups. However, they are not strictly comparable, because generally a deformed calyx containing a stone was removed by the operation, whereas secondarily dilated calyces remained. One cannot say what the recurrence rate in the deformed calyx might have been if it had not been removed. Some clue to this is perhaps given in Table IX in which the effect of leaving any remnant of the 341
TABLE IX.
Calyceal Neck
Znfluence of residual calyceal neck
Number
Per Cent
Recurrences
Incidence of Recurrence (Per Cent)
18
51.3
14 2
15.6 33.4
35 26.7 Remained Did not remain 90 68.7 4.6 Not clear 6 P = 0.0918: highly significant
calyceal neck is examined. Stewart’ has stressed the importance of this except in the upper calyx, where the proximity of the artery to the posterior segment renders this hazardous,8 and the dependent drainage makes it less essential. We have accordingly carefully and critically examined the postoperative IVPs to determine where any evidence of such a remnant could be detected. The figures apparently clearly indicate the great importance of this technical point in the operation. However, it is at the same time noteworthy that although there were eighteen recurrences in kidneys in which there was evidence of a residual calyceal neck, only nine of these actually recurred in the resected pole itself. An attempt was made to assess the importance of metabolic factors in these cases (Table X). All stone cases admitted for operation have routine biochemical investigations, including serum calcium, phosphorus and uric acid levels, tubular reabsorption of phosphate, and twenty-four-hour urinary excretion of calcium on the regular ward diet. These estimations, especially the serum levels, were repeated a number of times on each patient during hospitalization and on outpatient attendantes, and the serum levels were again checked on the follow-up examination. Table X indicates the number of cases in whom at least one result of the parameter indicated was conclusively outside normal limits. In the first row, it refers to one or more of the tests, not necessarily all three of them together. Six of these cases were
TABLE X.
Metabolic Factors Ca t, P i, TRP& Uric acid t Hypercalciuria
342
Evidence of metabolic defect
Number
Recurrences
Per Cent
23 34 17
9 5 5
39.0 14.7 29.4
found to have hyperparathyroidism and had a parathyroidectomy performed. It was not possible to detect any statistically significant difference between the different groups and the recurrence rates. Comment The present series of partial nephrectomies represents one of the largest series in terms of combined kidney-years followed up reported in the literature, with the notable exception of that recently reported by Rose and Fellow? extending the series of cases treated by Stewart.‘O Our results indicate that when an adequate follow-up is made, the ipsilateral true recurrence rate is much higher than generally believed in the past, and indeed, when compared with a similarly constituted group of simple pyelolithotomies performed in the same department, shows an insignificant difference in the recurrence rates. However, it should be noted that such a comparison, although often used, is not strictly valid because of differences in selection of the cases for the two operations. Those in whom simple pyelolithotomy was performed were usually those in whom calculi were present in the renal pelvis without evidence of localized renal involvement, whereas those in whom a specific calyx or calyces were implicated were usually treated by partial nephrectomy. It could well be argued that the latter group would have had a much higher incidence of recurrence than the former group if also treated by pyelolithotomy. The rationale for performing partial nephrectomy is generally considered to be twofold; first, that one is removing an anatomically distorted segment of the kidney in which stasis and infection are particularly likely to persist, and second, that one is removing a stone-bearing region of the kidney, whether one refers to Randall’s” plaques, Carr’s12 concretions, or a lithogenic
UROLOGY
/ APRIL1978 / VOLUMEXI,
NUMBER4
focus. The former of these premises is logical and receives support from the clear effect of leaving a calyceal neck remnant found in our series. With regard to the second premise, the in finding by Anderson I3 that calcification kidneys removed at postmortem is uniformly distributed throughout the whole kidney is of great importance. He concluded from his studies that although heavily mineralized renal tissue may be removed at partial nephrectomy, tissue which is just as heavily mineralized will remain. Our findings that 25 of the 34 recurrences (73.5 per cent) appeared in a region of the kidney other than that resected is of relevance here and fits in with Anderson’s conclusions. Moreover, it is of practical importance in indicating that although the performance of a more extensive partial nephrectomy might perhaps have prevented 9 recurrences, it could not be expected to have prevented the other 25. It would appear that the concept of a localized or segmental stone-bearing region of the kidney as a rationale for partial nephrectomy needs reconsideration. Our finding of a particularly high recurrence rate when there have been previous stones in the same kidney would appear to have important practical implications. In the past we have had a tendency to think that a history of recurrence in the same kidney, particularly if a previous conservative operation had been performed, strengthened the indication for a partial nephrectomy. It would now appear from our figures that this conclusion is not likely to be correct. Papathanassiadis and Swinney’* have suggested that partial nephrectomy has an additional advantage in encouraging the spontaneous passage of nascent calculi, which would otherwise lodge in a lower pole where they would enlarge. We have certainly seen the spontaneous passage of residual stones after partial nephrectomy, but as Singh, Marshall, and Blandy15 have shown, this may also frequently occur after other operations for stone, and we have been unable to draw any conclusions on this point from our series. The results of this survey may be summarized as indicating that there is a higher incidence of ipsilateral true recurrence of calculi after partial nephrectomy than has generally been believed
UROLOGY
/
APRIL 1978
/
VOLUME XI, NUMBER 4
in the past, and it is questionable whether there is any over-all advantage from this point of view in partial nephrectomy over the simpler pyelolithotomy. The history of previous stones in the same kidney or the contralateral one must be regarded as a point against rather than for the operation, as is the presence of multiple or scattered calculi. Factors such as the composition of the stone and the history or presence of infection do not appear to be of importance in this context. Where the operation is performed, the technical detail of careful removal of the neck of a calyx in the middle and lower groups, is confirmed to be of importance. The operation is logical when there is a clearly diseased or deformed segment of the kidney which on general surgical principles it would be unwise to leave, but cannot be recommended in the absence of this simply as a means of removing a stonebearing region of the kidney. Hadassah Medical Centre P.O.B. 499 Jerusalem, Israel (DR. CAINE) References 1. Pedersen JF: Partial nephrectomy for nephrolithiasis, Stand. J. Ural. Nephrol. 5: 171 (1971). 2. Myrvold H, and Fritjofsson A: Late results of partial nephrectomy for renal lithiasis, ibid. 5: 57 (1971). 3. Marshall V. et al: The natural historv of renal and ureteric calculi, Br. J. Urol. 47: 117 (1975). ’ 4. Williams RE: Long term survey of 538 patients with upper urinary tract stone, ibid. 35: 416 (1963). 5. Frank M, et al: Epidemiological investigation of urolithiasis in Israel, J. Ural. 81: 497 (1959). 6. Gertler R: Partial nephrectomy versus pyelolithotomy and nephrolithotomy in Hadassah Hospital, Jerusalem, M.D. Thesis, Hebrew University of Jerusalem (1971). 7. Stewart HH: Calcification and calculus formation in the upper urinary tract, Br. J. Urol. 27: 352 (1955). 8. Graves FT: The anatomy of the intrarenal arteries and its application to segmental resection of the kidney, ibid. 42: 132 (1954). 9. Rose MB, and Fellows OJ: Partial nephrectomy for stone disease, ibid. 49: 695 (1977). 10. Stewart HH: The surgery of the kidney in the treatment of renal stone. ibid. 32: 392 (1969). 11. Randall A: The origin and growth of renal calculi, Ann. Surg. 105: 1999 (1937). 12. Carr RJ: A new theory on the formation of renal calculi, Br. J. Urol. 26: 195 (1954). 13. Anderson CK: Partial nephrectomy a pathological evaluation, Proc. R. Sot. Med. 67: 459 (1974). 14. Papathanassiadis S, and Swinney J: Results of partial nephrectomy compared with pyelolithotomy and nephrolithotomy, Br. J. Urol. 38: 403 (1966). 15. Singh M, Marshall V, and Blandy J: The residual renal stone, ibid. 47: 125 (1975).
343
PARTIAL NEPHRECTOMY TREATMENT
IN SURGICAL
OF CALCULOUS
DISEASE
URI WALD, M.D. MARCO CAINE,
M.S., F.R.C.S.
HARVEY SOLOMON,
M.D.
From the Department of Urology, Hadassah University Hospital, Jerusalem, Israel
ABSTRACT - Of a total of 158 partial nephrectomies, a detailed follow-up for up to sixteen years was obtained in 131. The rate of true ipsilateral recurrences was 26 per cent. Computer analysis of various parameters indicated that a previous history of a stone in the same or the contralateral kidney, or the presence of multiple or scattered stones in the affected side, were associated with a particularly high recurrence rate. Urinary infection at the time of or prior to operation was not of prognostic signijcance. The importance of complete excision of the calyceal neck was confirmed. It was concluded that the operation is logical for removal of a diseased segment of kidney, but generally cannot be recommended in the hope of removing a stone-bearing area of kidney and hence reducing the recurrence rate.
It has been widely accepted for many years that the operation of choice in many cases of renal calculi, particularly those involving a calyx or calyces, is partial nephrectomy. This has been based on the belief that this operation greatly reduces the likelihood of a true recurrence of stone in the operated kidney, and hence fully justifies any possible slight increase in operative or postoperative complications as compared with pyelolithotomy or even nephrolithotomy. The validity of this belief has been put in doubt by two reports from Scandinavia, that of Pedersenl reporting a recurrence rate of 20.6 per cent in 150 operations followed up for a mean of 3.9 years, and that of Myrvold and Fritjoffson2 in which a recurrence rate of 43 per cent in 65 patients followed up for a mean of 9 years, was reported. These and many other recent authors have stressed the paramount importance of a long follow-up when attempting to assess the recurrence rate of renal calculi, whether after operation or after spontaneous passage. Marshall et al., 3 for example, have pointed out that recurrence may take place more than ten years
338
after a previous stone, and in Williams’4 series the average time taken for an ipsilateral recurrence (not necessarily after operation) was 8.4 years. Another point that is considerably clear is that many recurrent calculi may be entirely silent, at any rate for a prolonged period, and thus any figures for recurrence that are not based on a follow-up including roentgenography are liable to be fallacious. Owing to the very high incidence of renal calculi in our population, we have obtained a relatively large experience with this operation in our department; therefore, we decided to carry out a long-term follow-up of our cases to determine whether our late results supported the belief that we were greatly reducing the recurrence rate or whether, perhaps, they corresponded to those authors who found a disturbingly high recurrence rate. In addition, we hoped to be able to analyze the various parameters in relationship to recurrence to identify any factors that could be recognized as being significantly related to it, and hence perhaps more precisely to define the indications for this operation.
UROLOGY
/ APRIL 1978 / VOLUME
XI, NUMBER 4
No.
10
20
30
40
50
60
70
80
nws
Age distribution of patients with partial
FIGURE 1.
nephrectomy.
clamp was used on the pedicle, and hemostasis was obtained by direct suturing of the individual vessels on the cut surface with 4-O catgut. The pelvicalyceal opening was closed with continuous 3-O catgut. The ischemic time, which was recorded in all cases by the anesthetist, was rarely more than twenty minutes, and it was never found necessary to use local cooling of the kidney. Some of our staff reflected the capsule and used it to cover the cut surface, buttonholing it to prevent hematoma formation, and others did not leave any capsule. One can record that there was no difference in any parameters examined via the computer between these two methods.
Material and Method
Results
We have reviewed the cases of partial nephrectomy performed in our department during the years 1960 to 1976 inclusive. All the patients were invited for a personal interview, at which time in addition to an updating history and physical examination, a midstream specimen of urine was examined and cultured, blood chemistry checked, and an x-ray film taken. In those patients in whom a satisfactory postoperative IVP had already been obtained, only a plain film was taken in the first instance on the follow-up examination, the IVP being repeated if there was any suggestion of a recurrence. If no postoperative IVP had been taken, this was done on the occasion of the follow-up. All our patients with calculi have a routine plain roentgenogram performed before leaving the hospital, so we had evidence as to the presence or absence of any residual stones, the so-called “false” recurrences. All relevant data were extracted from the patient’s hospital records, and the old x-ray films were reviewed to determine details of the number and distribution of the stones, the functional and anatomic condition of the kidney before operation, and so forth. All the information obtained from the past records, follow-up examination, and roentgenograms past and present, was suitably coded and analyzed with the aid of a computer, thus enabling us to examine and identify any interrelationships between the various parameters recorded. The operations were performed by the residents or senior staff of our department, and the technique used was practically standardized. All our cases were performed by a “guillotine” section across the kidney using a scalpel, and none was done by a wedge resection. A soft
UROLOGY
/ APRIL1978 / VOLUMEXI,
NUMBER4
A total of 158 partial nephrectomies on 151 patients was performed in the period reviewed. In 5 patients the operations were bilateral, and in 2 patients two separate partial nephrectomies were performed on the same kidney. In 8 patients the operations were performed on a solitary kidney. There were 94 males and 57 females in the series, and the ages ranged from eleven to seventy-eight years (Fig. 1). The complications encountered in the 158 operations performed are listed in Table I, and are found to compare favorably with those in other published series. A satisfactory follow-up was obtained on 131 operations up to sixteen years, with a mean follow-up time of 5.85 years. Among these we found a total of 34 true ipsilateral recurrences, or an incidence of 26 per cent. The question arises as to whether or not the fact that this country has an extremely high incidence of urinary tract calculi (1.18 per cent of all the population according to Frank et al.)” results in an increased likelihood of recurrence after operation as compared with countries with an over-all lower incidence of calculi. An indication of this is afforded by the recurrence rate
TABLE
I.
Operative complications in 158 operations
Complications Death Secondary hemorrhage Fistula for more than ten days Wound dehiscence Secondary nephrectomy Closure of fistula
Number 1
3 1
4 2 1
339
TABLE II.
Previous history of ipsilateral
Calculus None Previous stone
Number
Recurrences
TABLE III.
Previous history of contralateral calculus
History
Number
Per Cent
16
20.3
34.6
Distribution
of calculi in kidney
Calculi
Number
Recurrences
TOTALS
26
Per Cent
2 0 0
50 0 0 - 18
4
15
2
61.5 1
TABLE V.
Recurrences
51
25
2
TABLE IV.
4 7 4 11
39
16
Not known P = 0.001: highly significant
18
10
9 49
Unilateral only 79 Presence or history of contralateral 52 P = 0.02: significant
Per Cent
8
80 Passed, 23 Operated, 26
Solitary Pelvis Lower calyx Upper calyx Stagbom
calculus
Infection
50
Relationship of urinary infection to recurrence Number
Recurrences
Per Cent
Before operation 69 Yes 58 No 4 Not known P = 0.5: not significant
19 13 2
27.5 22.4 50
At operation 63 Yes 68 No Not known 0 P = 0.4: not significant
20 14 0
31.7 20.6 0
At follow-up Yes 65 62 No 4 Not known P = 0.05: significant
25 8 1
38.5 12.9 25
of 118
possible relationships to recurrences, and from these the following results of importance have emerged. The history of a previous stone in the same kidney was found to be associated with an approximately fivefold increase in the likelihood of recurrence, a statistically highly significant result, and this was apparently even greater if that stone had had to be removed by a previous operation (Table II). Although not so
such patients followed up from our department by Gertler,6 33 true recurrences were found, or an incidence of 28 per cent. This is well within the generally accepted range of recurrence after pyelolithotomy and does not suggest an exaggerated tendency to recurrence in our population. This was a comparable group to our present series of partial nephrectomies. It had a follow-up extending also up to sixteen years, with a mean follow-up time of 5.3 years. The close relationship of the two recurrence rates, 28 per cent and 26 per cent, is therefore striking and significant. A large number of parameters were investigated with the aid of the computer for their
impressive, there is also statistically significant evidence of an increased likelihood of recurrence if a contralateral stone is present at the time of operation or had been present in the past (Table III). The relationship between the number and distribution of the stones in the operated kidney and the recurrence rate is summarized in Table IV. In view of the disparity in the numbers, the results here are statistically not of significance. However, if the trend of the figures was to be maintained in larger groups, it would appear that multiple calculi are more likely to recur than solitary ones, and those scattered throughout the kidney more so than multiple calculi confined to a
Multiple Single calyx + pelvis Scattered TOTALS
after simple
340
81 24
19 _ll_
23.5 j5.8_
105
30
28.6
pyelolithotomy.
In a series
UROLOGY / APRIL 1978 I VOLUMEXI, NUMBER4
TABLE VI.
Composition Phosphate stones Others
Total 23 108
Relationship of stone composition to infection and recurrence
Infected at or Before Operation
Not Infected
Recurrences
17 (74)* 77 (71)
6 (26) 31 (29)
8 (34.8) 26 (24 )
*Figuresin parenthesessignifyper cent.
solitary calyx. with or without an associated calculus in the renal pelvis. The question of the relationship of recurrence to urinary infection is of interest. There was no correlation between the recurrence rate and the presence of urinary infection prior to operation (Table V), nor was the apparent correlation with urinary infection at the time of operation of statistical significance (Table V). The same conclusion was reached by Myrvold and Fritjoffson2 and by Williams4 in their series. A relationship did appear to exist between recurrent stone formation and infection at the follow-up examination (Table V). However, whether or not this is causally related to the new stone formation or is the result of the presence of the stone is not clear. Separation of the group of phosphate stones, which may be considered to be more likely associated with infection, from other stones did not show any appreciable difference (Table VI). Despite these negative findings regarding infection, an examination of the resected part of the kidney did appear to indicate a relationship between the condition of the renal tissue and the risk of recurrence (Table VII). The proportion of normal to pathologic specimens is similar to that in Pedersen’s’ and in Myrvold and Fritjoffson’s’ series. The problem here is the interpretation of the pathologic changes. It appears clear these days that the so-called pyelonephritic changes do not necessarily imply an infective lesion and may simply indicate a nonspecific reaction to the irritation produced by the stone. Thus, these results are not necessarily in conflict with those relating to infection. An attempt was made to determine if there was any difference in the recurrence rates between the kidneys in which the dilated or deformed calyces were caused by the contained stone, or those in which such calyces were produced secondarily by obstruction by a stone elsewhere, or by a primary hydronephrosis
UROLOGY / APRIL1978 / VOLUMEXI, NUMBER4
TABLE VII.
Pathology of excised tissue
Number Recurrences Per Cent
Pathology Normal Pathologic N~~;,$oJophritic”)
25
0
0
99 7 P = 0.041: significant
32 2
32.3 28.6
TABLE VIII.
Condition of kidney at operation
Conditions
Number
Recurrences Per Cent
Dilatation or deformity of calyx due to contained stone(s) 84
24
28.6
Dilatation of calyx secondary to obstruction by stone
47
18
38.3
6
2
33.3
Primary hydronephrosis with secondary stones
(Table VIII). Those in the latter groups would be more likely to return to normal after removal of the obstructing stone or after plastic correction of the hydronephrosis, which was performed together with the partial nephrectomy when indicated. Here as the conditions are not mutually exclusive, the sums of the numbers exceed the total number of cases and recurrences. As can be seen, there is no significant difference between these groups. However, they are not strictly comparable, because generally a deformed calyx containing a stone was removed by the operation, whereas secondarily dilated calyces remained. One cannot say what the recurrence rate in the deformed calyx might have been if it had not been removed. Some clue to this is perhaps given in Table IX in which the effect of leaving any remnant of the 341
TABLE IX.
Calyceal Neck
Znfluence of residual calyceal neck
Number
Per Cent
Recurrences
Incidence of Recurrence (Per Cent)
18
51.3
14 2
15.6 33.4
35 26.7 Remained Did not remain 90 68.7 4.6 Not clear 6 P = 0.0918: highly significant
calyceal neck is examined. Stewart’ has stressed the importance of this except in the upper calyx, where the proximity of the artery to the posterior segment renders this hazardous,8 and the dependent drainage makes it less essential. We have accordingly carefully and critically examined the postoperative IVPs to determine where any evidence of such a remnant could be detected. The figures apparently clearly indicate the great importance of this technical point in the operation. However, it is at the same time noteworthy that although there were eighteen recurrences in kidneys in which there was evidence of a residual calyceal neck, only nine of these actually recurred in the resected pole itself. An attempt was made to assess the importance of metabolic factors in these cases (Table X). All stone cases admitted for operation have routine biochemical investigations, including serum calcium, phosphorus and uric acid levels, tubular reabsorption of phosphate, and twenty-four-hour urinary excretion of calcium on the regular ward diet. These estimations, especially the serum levels, were repeated a number of times on each patient during hospitalization and on outpatient attendantes, and the serum levels were again checked on the follow-up examination. Table X indicates the number of cases in whom at least one result of the parameter indicated was conclusively outside normal limits. In the first row, it refers to one or more of the tests, not necessarily all three of them together. Six of these cases were
TABLE X.
Metabolic Factors Ca t, P i, TRP& Uric acid t Hypercalciuria
342
Evidence of metabolic defect
Number
Recurrences
Per Cent
23 34 17
9 5 5
39.0 14.7 29.4
found to have hyperparathyroidism and had a parathyroidectomy performed. It was not possible to detect any statistically significant difference between the different groups and the recurrence rates. Comment The present series of partial nephrectomies represents one of the largest series in terms of combined kidney-years followed up reported in the literature, with the notable exception of that recently reported by Rose and Fellow? extending the series of cases treated by Stewart.‘O Our results indicate that when an adequate follow-up is made, the ipsilateral true recurrence rate is much higher than generally believed in the past, and indeed, when compared with a similarly constituted group of simple pyelolithotomies performed in the same department, shows an insignificant difference in the recurrence rates. However, it should be noted that such a comparison, although often used, is not strictly valid because of differences in selection of the cases for the two operations. Those in whom simple pyelolithotomy was performed were usually those in whom calculi were present in the renal pelvis without evidence of localized renal involvement, whereas those in whom a specific calyx or calyces were implicated were usually treated by partial nephrectomy. It could well be argued that the latter group would have had a much higher incidence of recurrence than the former group if also treated by pyelolithotomy. The rationale for performing partial nephrectomy is generally considered to be twofold; first, that one is removing an anatomically distorted segment of the kidney in which stasis and infection are particularly likely to persist, and second, that one is removing a stone-bearing region of the kidney, whether one refers to Randall’s” plaques, Carr’s12 concretions, or a lithogenic
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focus. The former of these premises is logical and receives support from the clear effect of leaving a calyceal neck remnant found in our series. With regard to the second premise, the in finding by Anderson I3 that calcification kidneys removed at postmortem is uniformly distributed throughout the whole kidney is of great importance. He concluded from his studies that although heavily mineralized renal tissue may be removed at partial nephrectomy, tissue which is just as heavily mineralized will remain. Our findings that 25 of the 34 recurrences (73.5 per cent) appeared in a region of the kidney other than that resected is of relevance here and fits in with Anderson’s conclusions. Moreover, it is of practical importance in indicating that although the performance of a more extensive partial nephrectomy might perhaps have prevented 9 recurrences, it could not be expected to have prevented the other 25. It would appear that the concept of a localized or segmental stone-bearing region of the kidney as a rationale for partial nephrectomy needs reconsideration. Our finding of a particularly high recurrence rate when there have been previous stones in the same kidney would appear to have important practical implications. In the past we have had a tendency to think that a history of recurrence in the same kidney, particularly if a previous conservative operation had been performed, strengthened the indication for a partial nephrectomy. It would now appear from our figures that this conclusion is not likely to be correct. Papathanassiadis and Swinney’* have suggested that partial nephrectomy has an additional advantage in encouraging the spontaneous passage of nascent calculi, which would otherwise lodge in a lower pole where they would enlarge. We have certainly seen the spontaneous passage of residual stones after partial nephrectomy, but as Singh, Marshall, and Blandy15 have shown, this may also frequently occur after other operations for stone, and we have been unable to draw any conclusions on this point from our series. The results of this survey may be summarized as indicating that there is a higher incidence of ipsilateral true recurrence of calculi after partial nephrectomy than has generally been believed
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in the past, and it is questionable whether there is any over-all advantage from this point of view in partial nephrectomy over the simpler pyelolithotomy. The history of previous stones in the same kidney or the contralateral one must be regarded as a point against rather than for the operation, as is the presence of multiple or scattered calculi. Factors such as the composition of the stone and the history or presence of infection do not appear to be of importance in this context. Where the operation is performed, the technical detail of careful removal of the neck of a calyx in the middle and lower groups, is confirmed to be of importance. The operation is logical when there is a clearly diseased or deformed segment of the kidney which on general surgical principles it would be unwise to leave, but cannot be recommended in the absence of this simply as a means of removing a stonebearing region of the kidney. Hadassah Medical Centre P.O.B. 499 Jerusalem, Israel (DR. CAINE) References 1. Pedersen JF: Partial nephrectomy for nephrolithiasis, Stand. J. Ural. Nephrol. 5: 171 (1971). 2. Myrvold H, and Fritjofsson A: Late results of partial nephrectomy for renal lithiasis, ibid. 5: 57 (1971). 3. Marshall V. et al: The natural historv of renal and ureteric calculi, Br. J. Urol. 47: 117 (1975). ’ 4. Williams RE: Long term survey of 538 patients with upper urinary tract stone, ibid. 35: 416 (1963). 5. Frank M, et al: Epidemiological investigation of urolithiasis in Israel, J. Ural. 81: 497 (1959). 6. Gertler R: Partial nephrectomy versus pyelolithotomy and nephrolithotomy in Hadassah Hospital, Jerusalem, M.D. Thesis, Hebrew University of Jerusalem (1971). 7. Stewart HH: Calcification and calculus formation in the upper urinary tract, Br. J. Urol. 27: 352 (1955). 8. Graves FT: The anatomy of the intrarenal arteries and its application to segmental resection of the kidney, ibid. 42: 132 (1954). 9. Rose MB, and Fellows OJ: Partial nephrectomy for stone disease, ibid. 49: 695 (1977). 10. Stewart HH: The surgery of the kidney in the treatment of renal stone. ibid. 32: 392 (1969). 11. Randall A: The origin and growth of renal calculi, Ann. Surg. 105: 1999 (1937). 12. Carr RJ: A new theory on the formation of renal calculi, Br. J. Urol. 26: 195 (1954). 13. Anderson CK: Partial nephrectomy a pathological evaluation, Proc. R. Sot. Med. 67: 459 (1974). 14. Papathanassiadis S, and Swinney J: Results of partial nephrectomy compared with pyelolithotomy and nephrolithotomy, Br. J. Urol. 38: 403 (1966). 15. Singh M, Marshall V, and Blandy J: The residual renal stone, ibid. 47: 125 (1975).
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