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Staghorn calculi treated by percutaneous nephrolithotomy: risk factors for recurrence
STAGHORN CALCULI TREATED BY PERCUTANEOUS NEPHROLITHOTOMY: RISK FACTORS FOR RECURRENCE FRED SAAD, M.D. RAYMOND FAUCHER, M.D. FRANCOIS MAUFFETTE, M.D.
JEAN-MARIE PAQUIN, M.D. JEAN-PAUL PERREAULT, M .D s LUC VALIQUETTE, M.D.
From the Division of Urology, Hopital Saint-Luc and Department of Surgery, Universite de Montreal, Montreal, Quebec, Canada
ABSTRACT-Since 1985 OUTprimary mode of theTapy foT staghorn calculi ht;6 been by percutaneous nephrolithotomy. Between lanuay 1985 and June 198,s we have treated 57 cases using this method. We reviewed the rate of recurrem:,? at a minimum of one-year follow-up and observed a 17 percent TecuTTencerate. Factors identified that were associated with an increased rate of recurremx were: positive urine CultuTes during follow-up (55 % TecuTTence vs 12 %); StOni? Temnant greater than 5 mm (27.3 % recurrence vs 13.8 %); and stone complexity (25 % recurrence for complex OT complete staghorn vs 9.7% for noncomplex OT partial staghorn). By identifying these risk factors we think that stone recurrence can be reduced and, with close follow-up, detected earlier to permit Lear invasive therapy if needed.
Since 1980 percutaneous nephrolithotomy has replaced, to a large extent, the need for open operation in the treatment of renal calculi. The addition of extracorporeal shock-wave lithotripsy (ESWL) has succeeded in reducing the use of the percutaneous approach. There remains however, the staghorn calculus which still requires percutaneous nephrolithotomy according to the majority of centers treating these complex stones. 1-5 We have used the percutaneous approach for the treatment of calculi in over 666 cases since 1984. Of these, 57 were staghorn calculi treated in 55 patients from January 1985 to July 1988. Our interest was to determine the recurrence rate in these patients at a minimum of twelve months and to identify risk factors for recurrence . Material and Methods From January 1985 to July 1988 we treated 55 patients with 57 staghorn calculi by percuta-
UROLOGY
/ FEBRUARY
1993
/
VOLUME
41, NUMBER 2
neous nephrolithotomy. Thirty-four women and 21 men between seventeen and seventythree years made up the group. Eval~lation of calculus was done using the PICA systlm.6 This system quantifies stone burden using I he linear dimension of the stone and the anatiomic complexity is determined by the number of infundibulocaliceal (IC) extensions. We arbitrarily divided these stones inbo two groups: Group l-complex stones, had a linear dimension of more than 109 mm and ,3 or more infundibulocaliceal extensions. ‘Rventy renal units were in this group. Group 2-noncomplex stones, had a linear dimension of less than 100 mm or less than 3 infundibulocaliceal extensions. Thirty-seven renal units were in this group. The main symptom was pain in 44 percent, urinary tract infection in 31 percent, and hematuria 14 percent; 9.0 percent were asymptomatic. A positive urine culture was found i,n 49 percent of patients. The bacteria identified was proteus in 55 percent, Escherichia coli in 18
141
TABLE I.
TABLE II.
Treatment
Average
Group 1
(no.) Operative sessions
1.98
1.72
2.56
(no.) Operative time (min) (first session) Operative time (min) (total)
1.89
1.59
2.45
98.2 171
98.1 139
percent, Klebsiella in 18 percent, coccus in 9 percent.
98.5 228
and entero-
Treatment Patients were treated by percutaneous nephrolithotomy under general anesthesia. The number of percutaneous tracts necessary for treatment was 1.9 on average (range l-5). We noted a significantly greater number of tracts if the stone was complex vs noncomplex, average 2.6 (range 2-5) vs 1.7 (range l-4), respectively. The number of operative sessions required was also greater if the stone was complex. One to four sessions for complex stones (average 2.45) and one to three sessions for noncomplex (average 1.59). Operative time was similar for the first operative session but significantly greater when total operative time was calculated for complex vs noncomplex stones (Table I)*
Stone analysis was done and showed struvite in 52 percent, calcium oxalate in 32 percent, and calcium phosphate, cystine, uric acid, and matrix in 4 percent each. Additional therapy was done on the majority of patients: in 34 patients renal irrigation was done with renacidin for an average of 6.7 days (range 2-25 days); 7 had a flexible nephroscopy; 6 had a Double J stent installed; 5 had ESWL (of a possible 18 since the acquisition of the lithotriptor); and 2 had ureteroscopy. Complications are listed in Table II. Results Based on x-ray film (KUB) or renal tomograms the following results were obtained. After treatment, 68.4 percent of patients were stone-free, 12.3 percent had a residual stone of less than 5 mm, and 19.3 percent had a stone fragment of >5 mm. Follow-up of at least twelve months (range 12-48 months) in 47 units showed a stone-free rate of 53 percent, 15 percent having calculi of less than 5 mm and 32
142
Complication
Group 2
Percutaneous tracts
Complications No.
Major Septicemia Hemorrhage ( > 2 units transfusion) Hemo/pneumothorax Death Nephrectomy Minor Bleeding (< 2 units transfused) Fever >38.5” Pelvic perforation Ureteral stone requiring reintervention
3 3 1
0 0 10
7 3 2
percent with calculi of greater than 5 mm. The overall rate of recurrence (defined as the appearance of a new stone or an increase in volume of an existing residual stone) was seventeen percent. Review of these cases identified three main risk factors which significantly increased the rate of recurrence. The first risk factor was urinary tract infection. Urine cultures done during follow-up showed that in patients with persistently positive urine cultures despite treatment (asymptomatic or symptomatic) the risk of recurrence was 55.6 percent versus a risk of only 12 percent if cultures were negative. The relative risk was 4.58. The second risk factor was stone status. In reviewing whether residual stones significantly altered the risk of recurrence we noted that stone-free units had a 13.8 percent risk of recurrence vs 14.3 percent if a stone fragment of less than 5 mm was present (no significant difference) and 27.3 percent risk if a stone fragment of greater than 5 mm was left behind. The relative risk was 1.98. The third risk factor was stone complexity. Overall if a staghorn calculi was complex (or complete staghorn) the risk of recurrence was 25 percent versus 9.7 percent if the calculus was noncomplex (or partial staghorn) giving a relative risk of 2.58. Comment The treatment of staghorn calculi remains a difficult task even with the advent of percutaneous nephrolithotomy and more recently ESWL. Numerous authors have confirmed the advantages of combining these two modalities
UROLOGY
I
FEBRUARY 1993
I VOLUME 41, NUMBER 2
of treatment to reduce morbidity in the treatment of large calculi. lm5Few articles however, report on the follow-up of these calculi with identifiable risk factors for recurrence.3 Boyce and Elkins report on anatrophic nephrolithotomy in 94 patients with a 17 percent recurrence rate at one to three years. In terms of residual stone rate percutaneous nephrolithotomy appears to be as effective as open surgery.8-e The addition of ESWL has permitted the reduction of the number of percutaneous tracts in the treatment of staghorn calculi but on the other hand the number of stone-free patients are reduced at hospital discharge with the hope that the post ESWL fragments will evacuate spontaneously.3 This mode of therapy may contribute to the increased recurrence rate with regard to two of the three risk factors identified. The persistent stone fragments of greater than 5 mm increased the risk of recurrence by twofold. Urinary tract infection which may persist due in part to the retained stone fragments after ESWL may also contribute to recurrence. We noted an increased rate of residual fragments in complex vs noncomplex stones (42 % vs 22 % ) . This difference, however, was not enough to explain the difference in recurrence. We believe these patients present additional risk factors to explain the increased rate of recurrence, but the exact nature of these risk factors remains to be determined. In conclusion percutaneous nephrolithotomy, with or without ESWL, is an acceptable mode of therapy for the treatment of staghorn calculi. A stone-free status remains the ultimate goal of
UROLOGY
/
FEBRUARY
1993
/ VOLUME 41, NUMBER 2
therapy. Patients must be followed regularly after treatment to control any identifiable metabolic risk factors for stone formation. Regular imaging procedures as well as urine cultures must be done to detect and hopefully to reduce recurrence. Particular attention must be given to highrisk patients with positive urine cultures, residual stone fragments of greater than 5 mm, and patients who initially presented with complex calculi. 1058 Saint-Denis Montreal, Quebec, Canada H2X 3J4 (DR. VALIQUETTE) References 1. Winfield HN, et al: Monotherapy of staghorn calculi: a comparative study between percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy, J Urol 139: 895 (1988). 2. Kahnoski RJ, et al: Combined percutaneous and extracorporeal shock wave lithotripsy for staghorn calculi: an alternative to anatrophic nephrolithotomy, J Urol 135: 679 (1986). 3. Schulze H, et al: Critical evaluation of treatment of staghorn calculi by percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy, J Urol 141: 822 (1989). 4. Eisenberger F, et al: Extracorporeal shock wave lithotripsy (ESWL) and endourology: an ideal combination for the treatment of kidney stones, World J Uro13: 41 (1985). 5. Schulze H, et al: Combined treatment of branched calculi by percutaneous nephrolithotomy and extracorporeal shock wave lithotrinsv. I Ural 135: 1138 (1986). 6. Griffith DP, and Valiquette L: PICA/burden: a staging system for upper tract urinary stones, J Urol 138: 253 (1987). 7. Boyce WH, and Elkins IB: Reconstructive renal surgery following anatrophic nephrolithotomy: follow-up of 100 consecutive cases, J Urol 111: 307 (1974). 8. Snyder JA, and Smith AD: Staghorn calculi: percutaneous extraction versus anatrophic nephrolithotomy, J Urol 136: 351 (1986). 9. Patterson DE, Segura JW, and LeRoy AJ: Longterm followup of patients treated by percutaneous ultrasonic lithotripsy for struvite staghorn calculi, J Endourol 1: 177 (1987).
143
JEAN-MARIE PAQUIN, M.D. JEAN-PAUL PERREAULT, M .D s LUC VALIQUETTE, M.D.
From the Division of Urology, Hopital Saint-Luc and Department of Surgery, Universite de Montreal, Montreal, Quebec, Canada
ABSTRACT-Since 1985 OUTprimary mode of theTapy foT staghorn calculi ht;6 been by percutaneous nephrolithotomy. Between lanuay 1985 and June 198,s we have treated 57 cases using this method. We reviewed the rate of recurrem:,? at a minimum of one-year follow-up and observed a 17 percent TecuTTencerate. Factors identified that were associated with an increased rate of recurremx were: positive urine CultuTes during follow-up (55 % TecuTTence vs 12 %); StOni? Temnant greater than 5 mm (27.3 % recurrence vs 13.8 %); and stone complexity (25 % recurrence for complex OT complete staghorn vs 9.7% for noncomplex OT partial staghorn). By identifying these risk factors we think that stone recurrence can be reduced and, with close follow-up, detected earlier to permit Lear invasive therapy if needed.
Since 1980 percutaneous nephrolithotomy has replaced, to a large extent, the need for open operation in the treatment of renal calculi. The addition of extracorporeal shock-wave lithotripsy (ESWL) has succeeded in reducing the use of the percutaneous approach. There remains however, the staghorn calculus which still requires percutaneous nephrolithotomy according to the majority of centers treating these complex stones. 1-5 We have used the percutaneous approach for the treatment of calculi in over 666 cases since 1984. Of these, 57 were staghorn calculi treated in 55 patients from January 1985 to July 1988. Our interest was to determine the recurrence rate in these patients at a minimum of twelve months and to identify risk factors for recurrence . Material and Methods From January 1985 to July 1988 we treated 55 patients with 57 staghorn calculi by percuta-
UROLOGY
/ FEBRUARY
1993
/
VOLUME
41, NUMBER 2
neous nephrolithotomy. Thirty-four women and 21 men between seventeen and seventythree years made up the group. Eval~lation of calculus was done using the PICA systlm.6 This system quantifies stone burden using I he linear dimension of the stone and the anatiomic complexity is determined by the number of infundibulocaliceal (IC) extensions. We arbitrarily divided these stones inbo two groups: Group l-complex stones, had a linear dimension of more than 109 mm and ,3 or more infundibulocaliceal extensions. ‘Rventy renal units were in this group. Group 2-noncomplex stones, had a linear dimension of less than 100 mm or less than 3 infundibulocaliceal extensions. Thirty-seven renal units were in this group. The main symptom was pain in 44 percent, urinary tract infection in 31 percent, and hematuria 14 percent; 9.0 percent were asymptomatic. A positive urine culture was found i,n 49 percent of patients. The bacteria identified was proteus in 55 percent, Escherichia coli in 18
141
TABLE I.
TABLE II.
Treatment
Average
Group 1
(no.) Operative sessions
1.98
1.72
2.56
(no.) Operative time (min) (first session) Operative time (min) (total)
1.89
1.59
2.45
98.2 171
98.1 139
percent, Klebsiella in 18 percent, coccus in 9 percent.
98.5 228
and entero-
Treatment Patients were treated by percutaneous nephrolithotomy under general anesthesia. The number of percutaneous tracts necessary for treatment was 1.9 on average (range l-5). We noted a significantly greater number of tracts if the stone was complex vs noncomplex, average 2.6 (range 2-5) vs 1.7 (range l-4), respectively. The number of operative sessions required was also greater if the stone was complex. One to four sessions for complex stones (average 2.45) and one to three sessions for noncomplex (average 1.59). Operative time was similar for the first operative session but significantly greater when total operative time was calculated for complex vs noncomplex stones (Table I)*
Stone analysis was done and showed struvite in 52 percent, calcium oxalate in 32 percent, and calcium phosphate, cystine, uric acid, and matrix in 4 percent each. Additional therapy was done on the majority of patients: in 34 patients renal irrigation was done with renacidin for an average of 6.7 days (range 2-25 days); 7 had a flexible nephroscopy; 6 had a Double J stent installed; 5 had ESWL (of a possible 18 since the acquisition of the lithotriptor); and 2 had ureteroscopy. Complications are listed in Table II. Results Based on x-ray film (KUB) or renal tomograms the following results were obtained. After treatment, 68.4 percent of patients were stone-free, 12.3 percent had a residual stone of less than 5 mm, and 19.3 percent had a stone fragment of >5 mm. Follow-up of at least twelve months (range 12-48 months) in 47 units showed a stone-free rate of 53 percent, 15 percent having calculi of less than 5 mm and 32
142
Complication
Group 2
Percutaneous tracts
Complications No.
Major Septicemia Hemorrhage ( > 2 units transfusion) Hemo/pneumothorax Death Nephrectomy Minor Bleeding (< 2 units transfused) Fever >38.5” Pelvic perforation Ureteral stone requiring reintervention
3 3 1
0 0 10
7 3 2
percent with calculi of greater than 5 mm. The overall rate of recurrence (defined as the appearance of a new stone or an increase in volume of an existing residual stone) was seventeen percent. Review of these cases identified three main risk factors which significantly increased the rate of recurrence. The first risk factor was urinary tract infection. Urine cultures done during follow-up showed that in patients with persistently positive urine cultures despite treatment (asymptomatic or symptomatic) the risk of recurrence was 55.6 percent versus a risk of only 12 percent if cultures were negative. The relative risk was 4.58. The second risk factor was stone status. In reviewing whether residual stones significantly altered the risk of recurrence we noted that stone-free units had a 13.8 percent risk of recurrence vs 14.3 percent if a stone fragment of less than 5 mm was present (no significant difference) and 27.3 percent risk if a stone fragment of greater than 5 mm was left behind. The relative risk was 1.98. The third risk factor was stone complexity. Overall if a staghorn calculi was complex (or complete staghorn) the risk of recurrence was 25 percent versus 9.7 percent if the calculus was noncomplex (or partial staghorn) giving a relative risk of 2.58. Comment The treatment of staghorn calculi remains a difficult task even with the advent of percutaneous nephrolithotomy and more recently ESWL. Numerous authors have confirmed the advantages of combining these two modalities
UROLOGY
I
FEBRUARY 1993
I VOLUME 41, NUMBER 2
of treatment to reduce morbidity in the treatment of large calculi. lm5Few articles however, report on the follow-up of these calculi with identifiable risk factors for recurrence.3 Boyce and Elkins report on anatrophic nephrolithotomy in 94 patients with a 17 percent recurrence rate at one to three years. In terms of residual stone rate percutaneous nephrolithotomy appears to be as effective as open surgery.8-e The addition of ESWL has permitted the reduction of the number of percutaneous tracts in the treatment of staghorn calculi but on the other hand the number of stone-free patients are reduced at hospital discharge with the hope that the post ESWL fragments will evacuate spontaneously.3 This mode of therapy may contribute to the increased recurrence rate with regard to two of the three risk factors identified. The persistent stone fragments of greater than 5 mm increased the risk of recurrence by twofold. Urinary tract infection which may persist due in part to the retained stone fragments after ESWL may also contribute to recurrence. We noted an increased rate of residual fragments in complex vs noncomplex stones (42 % vs 22 % ) . This difference, however, was not enough to explain the difference in recurrence. We believe these patients present additional risk factors to explain the increased rate of recurrence, but the exact nature of these risk factors remains to be determined. In conclusion percutaneous nephrolithotomy, with or without ESWL, is an acceptable mode of therapy for the treatment of staghorn calculi. A stone-free status remains the ultimate goal of
UROLOGY
/
FEBRUARY
1993
/ VOLUME 41, NUMBER 2
therapy. Patients must be followed regularly after treatment to control any identifiable metabolic risk factors for stone formation. Regular imaging procedures as well as urine cultures must be done to detect and hopefully to reduce recurrence. Particular attention must be given to highrisk patients with positive urine cultures, residual stone fragments of greater than 5 mm, and patients who initially presented with complex calculi. 1058 Saint-Denis Montreal, Quebec, Canada H2X 3J4 (DR. VALIQUETTE) References 1. Winfield HN, et al: Monotherapy of staghorn calculi: a comparative study between percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy, J Urol 139: 895 (1988). 2. Kahnoski RJ, et al: Combined percutaneous and extracorporeal shock wave lithotripsy for staghorn calculi: an alternative to anatrophic nephrolithotomy, J Urol 135: 679 (1986). 3. Schulze H, et al: Critical evaluation of treatment of staghorn calculi by percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy, J Urol 141: 822 (1989). 4. Eisenberger F, et al: Extracorporeal shock wave lithotripsy (ESWL) and endourology: an ideal combination for the treatment of kidney stones, World J Uro13: 41 (1985). 5. Schulze H, et al: Combined treatment of branched calculi by percutaneous nephrolithotomy and extracorporeal shock wave lithotrinsv. I Ural 135: 1138 (1986). 6. Griffith DP, and Valiquette L: PICA/burden: a staging system for upper tract urinary stones, J Urol 138: 253 (1987). 7. Boyce WH, and Elkins IB: Reconstructive renal surgery following anatrophic nephrolithotomy: follow-up of 100 consecutive cases, J Urol 111: 307 (1974). 8. Snyder JA, and Smith AD: Staghorn calculi: percutaneous extraction versus anatrophic nephrolithotomy, J Urol 136: 351 (1986). 9. Patterson DE, Segura JW, and LeRoy AJ: Longterm followup of patients treated by percutaneous ultrasonic lithotripsy for struvite staghorn calculi, J Endourol 1: 177 (1987).
143