Robert Mendez - Academia.edu (original) (raw)
Papers by Robert Mendez
Transplantation, 1997
As the number of patients on the United States kidney transplant list increases, investigation in... more As the number of patients on the United States kidney transplant list increases, investigation into the utility of transplanting organs formerly considered marginal or undesirable has intensified. Using kidneys from hepatitis B surface antigen (HBsAg)-positive donors is thought to place recipients at excessive risk of graft failure, morbidity, and mortality. However, the risks of using kidneys from HBsAg-negative but hepatitis B core antibody (HBcAb)-positive donors have not been defined. Between 1990 and 1994, our group transplanted 1067 cadaveric kidneys, including 38 from HBsAg(-)/HBcAb(+) donors. Of these 38 kidneys, 27 were transplanted into HBcAb(-) recipients (group 1) and 11 were transplanted into HBcAb(+) recipients (group 2). Group 1 and 2 patients received no hepatitis immunoglobulin therapy after transplantation and received the same immunosuppression and rejection therapies as recipients of kidneys from HBcAb(-) donors. After transplantation, none of the group 1 patients became HBsAg(+), three became hepatitis B surface antibody (HBsAb)-positive, and two became HBcAb(+). Of the group 2 patients, none became newly HBsAg(+) or HBsAb(+). No patient receiving a kidney from an HBsAg(-)/HBcAb(+) donor developed signs or symptoms of clinical hepatitis B. Graft and patient survival rates were similar in both groups and similar to the rates of the 1029 recipients of kidneys from HBcAb(-) donors. Recipients of kidneys from HBsAg(-)/HBcAb(+) donors are at a small risk of hepatitis B seroconversion but are at no excess risk of graft failure or short-term morbidity or mortality.
Journal of Clinical Virology, 2004
Background: Hepatitis C virus (HCV) is frequently a silent infection in hemodialysis (HD) patient... more Background: Hepatitis C virus (HCV) is frequently a silent infection in hemodialysis (HD) patients with a prevalence of 8-10%. Improving HCV detection in this population prior to transplantation is critical both for infection control and optimal patient care. Objectives: To assess the current HCV testing practice of the National Institute for Transplantation (PCR testing of enzyme immunoassay (EIA) positive HD patients) by evaluating a subset of EIA positive and EIA negative samples with the VERSANT ® HCV RNA Qualitative Assay based on transcription mediated amplification (HCV Qual (TMA)) (sensitivity ≤9.6 IU/ml) and in-house PCR (HCV Qual (PCR)) (sensitivity ∼149 IU/ml). Study design: 2321 HD patients were screened by Abbott HCV EIA 2.0. A subset of 80/169 E IA positive samples and 100/2152 EIA negative samples were tested by both assays. TMA/PCR discordant samples were genotyped. Results: PCR and TMA gave concordant results in 67/80 (83.8%) of EIA positive samples. 11/80 (14.7%) were reactive by HCV Qual (TMA), but not by HCV Qual (PCR); 2/80 (2.7%) were reactive by HCV Qual (PCR), but not by HCV Qual (TMA). 2/100 (2%) EIA negative samples were reactive and 95/100 (95%) were non-reactive by both assays. Three (3%) were only HCV Qual (TMA) reactive. 11/14 TMA+/PCR-samples with sufficient volume were genotyped. Conclusions: HCV Qual (TMA) identified active HCV infection in more EIA positive and EIA negative patients than HCV Qual (PCR) and should be part of our testing algorithm.
Urology, 1974
Over a three-{tear period, 23 kidneys with multiple renal arteries were transplanted. Four ~llpes... more Over a three-{tear period, 23 kidneys with multiple renal arteries were transplanted. Four ~llpes of vascular anastomoses were used: Carrel aortic patches; accessory artery to main renal arteryanastomoses; double renal artery anastomoses to the external iliac artery; and anastomoses of the conjoined arteries to the external iliac artery. The results in this series compared favorably with a similar group of single artery transplants. The indications and hemodynamic justification for each procedure are presented. 4].0 UROLOGY / AI~ILI974 / VOLUIVIEIII, NUMI31~4
Transplantation, 1997
Chronic red cell aplasia can develop in immunocompromised patients including transplant recipient... more Chronic red cell aplasia can develop in immunocompromised patients including transplant recipients infected with parvovirus B19 (PV B19). Renal involvement with PV B19 infection is not well-recognized. We diagnosed erythroid hypoplasia associated with PV B19 infection in three renal transplant recipients; one of them developed de novo collapsing glomerulopathy. These patients were treated with intravenous immunoglobulin (IVIG). In two patients, anemia responded promptly to IVIG therapy. One of them had recurrence of anemia that responded to a second course of IVIG. Despite IVIG treatment, persistent infection with PV B19, recurrent anemia, and de novo collapsing glomerulopathy leading to allograft failure developed in the third patient, who had received the most intense immunosuppression. These findings indicate that PV B19 infection in transplant recipients can cause chronic red cell aplasia that generally responds to IVIG therapy. In some patients, particularly those who are heavily immunosuppressed, infection may persist despite treatment. As the cellular receptor for PV B19 is expressed in the kidney, persistent infection may result in development of glomerulopathies in these patients.
American Journal of Nephrology, 1995
the control group showed signs compatible with recurrence of focal and segmental glomeruloscleros... more the control group showed signs compatible with recurrence of focal and segmental glomerulosclerosis and Background. Outcome and the issue of recurrence of disease in systemic lupus erythematosus (SLE ) renal membranous glomerulonephritis. There was a wide variation in serum levels of antinuclear antibodies. A transplant recipients is still a matter of controversy. There is a lack of comparative studies with non-SLE wide variation in complement levels was also observed, but with a tendency towards low C4 levels. patients. The aim of this paper is to compare renal transplantation in lupus patients with a similar Conclusions. The safety of renal transplantation in SLE patients is equivalent to a matched case-control matched non-SLE group. Methods. Forty-five patients with systemic lupus eryth-group with a similar rate of recurrence of disease. ematosus subjected to 48 kidney transplants were Key words: renal transplantation; systemic lupus studied. For comparative purposes, a case-control erythematosus population was selected, matched for gender, race, type of donor, age, and time of transplantation. Patients with non-glomerulonephritis diseases were excluded.
Transplantation, 1982
A donor-specific transfusion (DST) protocol was carried out in 25 recipients obtaining kidneys fr... more A donor-specific transfusion (DST) protocol was carried out in 25 recipients obtaining kidneys from live-related one-haplotype-disparate high stimulating mixed lymphocyte culture (MLC) donors. The protocol consisted of the recipient receiving a transfusion of 200 ml of donor ...
Transplantation, 1997
The optimal use of very young cadaveric kidneys (from donors less than 4 years old) remains contr... more The optimal use of very young cadaveric kidneys (from donors less than 4 years old) remains controversial. High rates of technical complications and poor functional results compared with adult donor kidneys have been reported. The use of en bloc transplantation to overcome these problems has been advocated, although en bloc transplantation halves the number of potential transplants from very young donors. We studied the technical and functional results of 91 transplants from very young donors performed at our institution between 1984 and 1995. This included 59 single and 22 en bloc procedures involving first transplants and 7 single and 3 en bloc procedures involving retransplantation. Individual surgeon preference dictated the use of either the single or en bloc technique. Kidneys smaller than 6 cm tended to be transplanted en bloc, and lighter patients were generally given preference for receiving pediatric kidneys. Patients received sequential cyclosporine-based quadruple immunosuppression. En bloc kidneys had a 1-year and 5-year graft survival of 82% and 70%, respectively. Single kidneys had a 1-year and 5-year graft survival of 64% and 40%. Kidneys that avoided acute rejection episodes and that were transplanted into heavier or male recipients had better long-term survival. Kidneys from donors less than 2 years old did poorly whether transplanted en bloc or singly. Better HLA matching improved short-term, but not long-term, graft survival, whereas cold ischemic time did not have statistically significant association with differences in graft survival. Eleven percent of the transplants had ureteral leaks, but only one kidney was lost. Ten transplants had vascular complications leading to graft loss, whereas two episodes of arterial stenosis were successfully treated with percutaneous angioplasty. En bloc transplantation optimizes the outcome of transplantation with very young kidneys. We recommend induction therapy and cyclosporine immunosuppression with cyclosporine levels similar to adult target levels to minimize rejection episodes and, thus, improve outcome. These kidneys should be distributed nationally, because better HLA matching is associated with improved short-term graft survival. Our high ureteral leak rate indicates that alternatives to unstented ureteroneocystostomy should be considered.
Transplantation, 1998
In this study, we compare cholesterol levels during the first year after renal transplantation in... more In this study, we compare cholesterol levels during the first year after renal transplantation in FK506 (Prograf)- and cyclosporine-treated patients matched for cumulative first-year steroid dose and hypercholesterolemia risk factors. All patients had pretransplant cholesterol levels < 200 mg/dl. At 3 months posttransplant, 68% of the cyclosporine-treated patients had at least one cholesterol level greater than 200 mg/dl compared with 30% of the FK506-treated patients (P < 0.05). At the end of the year, 26% of FK506- and 67% of cyclosporine-treated patients remained hypercholesterolemic (P < 0.05). We conclude that cyclosporine has inherently more effect on cholesterol levels than FK506 during the first year after kidney transplantation.
The lifetime incidence of low back pain in the general population is estimated to be 60% to 80%. ... more The lifetime incidence of low back pain in the general population is estimated to be 60% to 80%. At a cost of $24 billion per year, the medical treatment of low back pain is the leading compensable cost of injury in the workplace (1). Research suggests that degenerating intervertebral discs are the primary source of low back pain. Conservative management, to include medication, physical therapy, rest, modalities, and patient education, is ineffective in cases of chronic low back pain Background: To assess whether unilateral L2 infi ltration with local anesthetic can be used to identify patients who will have negative discograms and thus eliminate the need for the discogram. Discogenic low-back pain is considered to have afferent pathways in the sinuvertebral nerves, mainly originating from the ventral rami of the spinal nerves. There is evidence that pain arising from the lower lumbar intervertebral discs may be transmitted through the sympathetic afferent fi bers contained in the L2 spinal nerve root. Provocative discography, within the context of other clinical data, is the current "gold standard" by which to diagnose discogenic low-back pain, but a far more invasive procedure than L2 infi ltration.
Regional Anesthesia and Pain Medicine, 2006
Objective: The purpose of this study is to inform readers of potential catastrophic complications... more Objective: The purpose of this study is to inform readers of potential catastrophic complications associated with performing cervical transforaminal epidural steroid injections.
Transplantation, 2005
This 36-month, randomized, parallel-group study compared safety and efficacy of two doses of ever... more This 36-month, randomized, parallel-group study compared safety and efficacy of two doses of everolimus with mycophenolate mofetil (MMF) in de novo renal-transplant recipients. Renal-allograft recipients received 1.5 mg/day or 3 mg/day of everolimus or 2 g/day of MMF, plus full-dose cyclosporine (CsA) and corticosteroids after randomization. For at least their first year, patients received study medication according to a double-blinded, double-dummy design. Concerns over nephrotoxicity led to a protocol amendment to an open-label design with reduced CsA troughs. Incidences of primary efficacy failure at 36 months (biopsy-proven acute rejection, graft loss, death, or loss to follow-up) were everolimus 1.5 mg/day, 33.7% (65/193); everolimus 3 mg/day, 34.0% (66/194); and MMF, 31.1% (61/196) (P=0.810). Antibody-treated acute rejection at 36 months was significantly lower with everolimus 1.5 mg (9.8%) than MMF (18.4%, P=0.014). Discontinuation for adverse events was more frequent with everolimus and hemolytic uremic syndrome, lymphoproliferative disease, and proteinuria, and higher serum creatinine occurred at increased frequency relative to the MMF arm. Creatinine levels in the everolimus arms were stable in follow-up: the mean rise in creatinine over the first 6 months of the open-label phase was 3 micromol/L or greater with everolimus and 7 micromol/L with MMF. However, serum creatinine levels were lower in the MMF group throughout. Death and graft loss were higher in the everolimus arms (not significant). As part of triple-drug immunosuppression, everolimus (1.5 or 3 mg/day) was as efficacious as MMF, although the side-effect profile featured increased adverse events. Nephrotoxicity/calcineurin-inhibitor-related adverse events will require judicious lowering of CsA exposure with monitoring of everolimus troughs.
Urology, 1977
Review of ureteral injuries treated in the past ten years at the Los Angeles County-University of... more Review of ureteral injuries treated in the past ten years at the Los Angeles County-University of Souther California Medical Center revealed 9 cases of traumatic injury which escaped immediate recognition. These patients were found to have a poor prognosis with a higher incidence of nephrectomy when compared with those patients with immediate diagnosis and treatment.
Transplantation, 1997
As the number of patients on the United States kidney transplant list increases, investigation in... more As the number of patients on the United States kidney transplant list increases, investigation into the utility of transplanting organs formerly considered marginal or undesirable has intensified. Using kidneys from hepatitis B surface antigen (HBsAg)-positive donors is thought to place recipients at excessive risk of graft failure, morbidity, and mortality. However, the risks of using kidneys from HBsAg-negative but hepatitis B core antibody (HBcAb)-positive donors have not been defined. Between 1990 and 1994, our group transplanted 1067 cadaveric kidneys, including 38 from HBsAg(-)/HBcAb(+) donors. Of these 38 kidneys, 27 were transplanted into HBcAb(-) recipients (group 1) and 11 were transplanted into HBcAb(+) recipients (group 2). Group 1 and 2 patients received no hepatitis immunoglobulin therapy after transplantation and received the same immunosuppression and rejection therapies as recipients of kidneys from HBcAb(-) donors. After transplantation, none of the group 1 patients became HBsAg(+), three became hepatitis B surface antibody (HBsAb)-positive, and two became HBcAb(+). Of the group 2 patients, none became newly HBsAg(+) or HBsAb(+). No patient receiving a kidney from an HBsAg(-)/HBcAb(+) donor developed signs or symptoms of clinical hepatitis B. Graft and patient survival rates were similar in both groups and similar to the rates of the 1029 recipients of kidneys from HBcAb(-) donors. Recipients of kidneys from HBsAg(-)/HBcAb(+) donors are at a small risk of hepatitis B seroconversion but are at no excess risk of graft failure or short-term morbidity or mortality.
Journal of Clinical Virology, 2004
Background: Hepatitis C virus (HCV) is frequently a silent infection in hemodialysis (HD) patient... more Background: Hepatitis C virus (HCV) is frequently a silent infection in hemodialysis (HD) patients with a prevalence of 8-10%. Improving HCV detection in this population prior to transplantation is critical both for infection control and optimal patient care. Objectives: To assess the current HCV testing practice of the National Institute for Transplantation (PCR testing of enzyme immunoassay (EIA) positive HD patients) by evaluating a subset of EIA positive and EIA negative samples with the VERSANT ® HCV RNA Qualitative Assay based on transcription mediated amplification (HCV Qual (TMA)) (sensitivity ≤9.6 IU/ml) and in-house PCR (HCV Qual (PCR)) (sensitivity ∼149 IU/ml). Study design: 2321 HD patients were screened by Abbott HCV EIA 2.0. A subset of 80/169 E IA positive samples and 100/2152 EIA negative samples were tested by both assays. TMA/PCR discordant samples were genotyped. Results: PCR and TMA gave concordant results in 67/80 (83.8%) of EIA positive samples. 11/80 (14.7%) were reactive by HCV Qual (TMA), but not by HCV Qual (PCR); 2/80 (2.7%) were reactive by HCV Qual (PCR), but not by HCV Qual (TMA). 2/100 (2%) EIA negative samples were reactive and 95/100 (95%) were non-reactive by both assays. Three (3%) were only HCV Qual (TMA) reactive. 11/14 TMA+/PCR-samples with sufficient volume were genotyped. Conclusions: HCV Qual (TMA) identified active HCV infection in more EIA positive and EIA negative patients than HCV Qual (PCR) and should be part of our testing algorithm.
Urology, 1974
Over a three-{tear period, 23 kidneys with multiple renal arteries were transplanted. Four ~llpes... more Over a three-{tear period, 23 kidneys with multiple renal arteries were transplanted. Four ~llpes of vascular anastomoses were used: Carrel aortic patches; accessory artery to main renal arteryanastomoses; double renal artery anastomoses to the external iliac artery; and anastomoses of the conjoined arteries to the external iliac artery. The results in this series compared favorably with a similar group of single artery transplants. The indications and hemodynamic justification for each procedure are presented. 4].0 UROLOGY / AI~ILI974 / VOLUIVIEIII, NUMI31~4
Transplantation, 1997
Chronic red cell aplasia can develop in immunocompromised patients including transplant recipient... more Chronic red cell aplasia can develop in immunocompromised patients including transplant recipients infected with parvovirus B19 (PV B19). Renal involvement with PV B19 infection is not well-recognized. We diagnosed erythroid hypoplasia associated with PV B19 infection in three renal transplant recipients; one of them developed de novo collapsing glomerulopathy. These patients were treated with intravenous immunoglobulin (IVIG). In two patients, anemia responded promptly to IVIG therapy. One of them had recurrence of anemia that responded to a second course of IVIG. Despite IVIG treatment, persistent infection with PV B19, recurrent anemia, and de novo collapsing glomerulopathy leading to allograft failure developed in the third patient, who had received the most intense immunosuppression. These findings indicate that PV B19 infection in transplant recipients can cause chronic red cell aplasia that generally responds to IVIG therapy. In some patients, particularly those who are heavily immunosuppressed, infection may persist despite treatment. As the cellular receptor for PV B19 is expressed in the kidney, persistent infection may result in development of glomerulopathies in these patients.
American Journal of Nephrology, 1995
the control group showed signs compatible with recurrence of focal and segmental glomeruloscleros... more the control group showed signs compatible with recurrence of focal and segmental glomerulosclerosis and Background. Outcome and the issue of recurrence of disease in systemic lupus erythematosus (SLE ) renal membranous glomerulonephritis. There was a wide variation in serum levels of antinuclear antibodies. A transplant recipients is still a matter of controversy. There is a lack of comparative studies with non-SLE wide variation in complement levels was also observed, but with a tendency towards low C4 levels. patients. The aim of this paper is to compare renal transplantation in lupus patients with a similar Conclusions. The safety of renal transplantation in SLE patients is equivalent to a matched case-control matched non-SLE group. Methods. Forty-five patients with systemic lupus eryth-group with a similar rate of recurrence of disease. ematosus subjected to 48 kidney transplants were Key words: renal transplantation; systemic lupus studied. For comparative purposes, a case-control erythematosus population was selected, matched for gender, race, type of donor, age, and time of transplantation. Patients with non-glomerulonephritis diseases were excluded.
Transplantation, 1982
A donor-specific transfusion (DST) protocol was carried out in 25 recipients obtaining kidneys fr... more A donor-specific transfusion (DST) protocol was carried out in 25 recipients obtaining kidneys from live-related one-haplotype-disparate high stimulating mixed lymphocyte culture (MLC) donors. The protocol consisted of the recipient receiving a transfusion of 200 ml of donor ...
Transplantation, 1997
The optimal use of very young cadaveric kidneys (from donors less than 4 years old) remains contr... more The optimal use of very young cadaveric kidneys (from donors less than 4 years old) remains controversial. High rates of technical complications and poor functional results compared with adult donor kidneys have been reported. The use of en bloc transplantation to overcome these problems has been advocated, although en bloc transplantation halves the number of potential transplants from very young donors. We studied the technical and functional results of 91 transplants from very young donors performed at our institution between 1984 and 1995. This included 59 single and 22 en bloc procedures involving first transplants and 7 single and 3 en bloc procedures involving retransplantation. Individual surgeon preference dictated the use of either the single or en bloc technique. Kidneys smaller than 6 cm tended to be transplanted en bloc, and lighter patients were generally given preference for receiving pediatric kidneys. Patients received sequential cyclosporine-based quadruple immunosuppression. En bloc kidneys had a 1-year and 5-year graft survival of 82% and 70%, respectively. Single kidneys had a 1-year and 5-year graft survival of 64% and 40%. Kidneys that avoided acute rejection episodes and that were transplanted into heavier or male recipients had better long-term survival. Kidneys from donors less than 2 years old did poorly whether transplanted en bloc or singly. Better HLA matching improved short-term, but not long-term, graft survival, whereas cold ischemic time did not have statistically significant association with differences in graft survival. Eleven percent of the transplants had ureteral leaks, but only one kidney was lost. Ten transplants had vascular complications leading to graft loss, whereas two episodes of arterial stenosis were successfully treated with percutaneous angioplasty. En bloc transplantation optimizes the outcome of transplantation with very young kidneys. We recommend induction therapy and cyclosporine immunosuppression with cyclosporine levels similar to adult target levels to minimize rejection episodes and, thus, improve outcome. These kidneys should be distributed nationally, because better HLA matching is associated with improved short-term graft survival. Our high ureteral leak rate indicates that alternatives to unstented ureteroneocystostomy should be considered.
Transplantation, 1998
In this study, we compare cholesterol levels during the first year after renal transplantation in... more In this study, we compare cholesterol levels during the first year after renal transplantation in FK506 (Prograf)- and cyclosporine-treated patients matched for cumulative first-year steroid dose and hypercholesterolemia risk factors. All patients had pretransplant cholesterol levels < 200 mg/dl. At 3 months posttransplant, 68% of the cyclosporine-treated patients had at least one cholesterol level greater than 200 mg/dl compared with 30% of the FK506-treated patients (P < 0.05). At the end of the year, 26% of FK506- and 67% of cyclosporine-treated patients remained hypercholesterolemic (P < 0.05). We conclude that cyclosporine has inherently more effect on cholesterol levels than FK506 during the first year after kidney transplantation.
The lifetime incidence of low back pain in the general population is estimated to be 60% to 80%. ... more The lifetime incidence of low back pain in the general population is estimated to be 60% to 80%. At a cost of $24 billion per year, the medical treatment of low back pain is the leading compensable cost of injury in the workplace (1). Research suggests that degenerating intervertebral discs are the primary source of low back pain. Conservative management, to include medication, physical therapy, rest, modalities, and patient education, is ineffective in cases of chronic low back pain Background: To assess whether unilateral L2 infi ltration with local anesthetic can be used to identify patients who will have negative discograms and thus eliminate the need for the discogram. Discogenic low-back pain is considered to have afferent pathways in the sinuvertebral nerves, mainly originating from the ventral rami of the spinal nerves. There is evidence that pain arising from the lower lumbar intervertebral discs may be transmitted through the sympathetic afferent fi bers contained in the L2 spinal nerve root. Provocative discography, within the context of other clinical data, is the current "gold standard" by which to diagnose discogenic low-back pain, but a far more invasive procedure than L2 infi ltration.
Regional Anesthesia and Pain Medicine, 2006
Objective: The purpose of this study is to inform readers of potential catastrophic complications... more Objective: The purpose of this study is to inform readers of potential catastrophic complications associated with performing cervical transforaminal epidural steroid injections.
Transplantation, 2005
This 36-month, randomized, parallel-group study compared safety and efficacy of two doses of ever... more This 36-month, randomized, parallel-group study compared safety and efficacy of two doses of everolimus with mycophenolate mofetil (MMF) in de novo renal-transplant recipients. Renal-allograft recipients received 1.5 mg/day or 3 mg/day of everolimus or 2 g/day of MMF, plus full-dose cyclosporine (CsA) and corticosteroids after randomization. For at least their first year, patients received study medication according to a double-blinded, double-dummy design. Concerns over nephrotoxicity led to a protocol amendment to an open-label design with reduced CsA troughs. Incidences of primary efficacy failure at 36 months (biopsy-proven acute rejection, graft loss, death, or loss to follow-up) were everolimus 1.5 mg/day, 33.7% (65/193); everolimus 3 mg/day, 34.0% (66/194); and MMF, 31.1% (61/196) (P=0.810). Antibody-treated acute rejection at 36 months was significantly lower with everolimus 1.5 mg (9.8%) than MMF (18.4%, P=0.014). Discontinuation for adverse events was more frequent with everolimus and hemolytic uremic syndrome, lymphoproliferative disease, and proteinuria, and higher serum creatinine occurred at increased frequency relative to the MMF arm. Creatinine levels in the everolimus arms were stable in follow-up: the mean rise in creatinine over the first 6 months of the open-label phase was 3 micromol/L or greater with everolimus and 7 micromol/L with MMF. However, serum creatinine levels were lower in the MMF group throughout. Death and graft loss were higher in the everolimus arms (not significant). As part of triple-drug immunosuppression, everolimus (1.5 or 3 mg/day) was as efficacious as MMF, although the side-effect profile featured increased adverse events. Nephrotoxicity/calcineurin-inhibitor-related adverse events will require judicious lowering of CsA exposure with monitoring of everolimus troughs.
Urology, 1977
Review of ureteral injuries treated in the past ten years at the Los Angeles County-University of... more Review of ureteral injuries treated in the past ten years at the Los Angeles County-University of Souther California Medical Center revealed 9 cases of traumatic injury which escaped immediate recognition. These patients were found to have a poor prognosis with a higher incidence of nephrectomy when compared with those patients with immediate diagnosis and treatment.