Int Urol Nephrol DOI 10.1007/s11255-017-1674-z
UROLOGY - ORIGINAL PAPER
Perioperative serum creatinine changes and ureteral injury Sam Siddighi1,5 · Junchan J. Yune2 · Nicole B. Kwon1 · Jeffrey S. Hardesty1 · Joo H. Kim3 · Philip J. Chan4
Received: 10 May 2017 / Accepted: 5 August 2017 © Springer Science+Business Media B.V. 2017
Abstract Purpose To illustrate a simple method that screens for ureteral injury in the acute postoperative period after urogynecologic surgeries. Methods Serum creatinine measurements in the preoperative (baseline) and postoperative periods of urogynecologic surgeries were determined and the correlation of the change to ureteral injury and/or obstruction analyzed. The sample size calculation showed 7 cases and 28 controls were sufficient to detect significant changes in creatinine. Each of the seven cases was matched for age and type of surgery with a control patient in a 1:4 ratio following standard protocol. Results Chart review of patients (273 cases) undergoing urogynecologic surgeries from October 2009 to June 2014 were undertaken. There were 7 cases of ureteral injury and 28 matching control cases. All cases had intraoperative cystoscopy confirming bilateral ureteral flow. In the ureteral injury group, blockage of ureter was confirmed by CT scan
with IV contrast. There was a 59.8% increase in serum creatinine levels postoperative in the ureteral injury group versus a 3.8% decrease in controls. A difference of creatinine levels greater than or equal to 0.3 mg/dL over baseline was evident in ureteral injury cases. Conclusion A small change in serum creatinine level over baseline after urogynecologic surgery alerted the possibility of ureteral injury or obstruction. A simple and inexpensive evaluation of perioperative creatinine levels can promptly diagnose ureteral damage in the acute postoperative period for gynecologic reconstructive surgeries.
* Sam Siddighi [email protected]
2
Junchan J. Yune [email protected]
Urology Department, Loma Linda University School of Medicine, 11234 Anderson St., Coleman Suite 11105, Loma Linda, CA 92354, USA
3
Nicole B. Kwon [email protected]
Loma Linda University School of Medicine, 11234 Anderson St., Loma Linda, CA 92354, USA
4
Gynecology and Obstetrics Department, Loma Linda University School of Medicine, 11370 Anderson St., Suite 3950, Loma Linda, CA 92354, USA
5
11350 Anderson St., Suite 3900, Loma Linda, CA, USA
Jeffrey S. Hardesty [email protected] Joo H. Kim [email protected]
Keywords Creatinine · Ureter · Surgery injury · Urogynecology
Philip J. Chan [email protected] 1
Female Pelvic Medicine and Reconstructive Surgery, Loma Linda University School of Medicine, 11234 Anderson St., Coleman Suite 11105, Loma Linda, CA 92345, USA
13
Vol.:(0123456789)
Introduction Ureteral injury during gynecological surgery although uncommon is a complication that requires prompt diagnosis in order to avoid significant morbidity. The incidence of ureteral injury from pelvic reconstructive surgery ranges from 0.3 to 11% [1]. According to Doweling and colleagues, a reported 75% of iatrogenic ureteral injuries result from gynecological surgeries [2]. Ureteral injury occurs from direct or indirect damage via crush injury, ligation, transection of the ureter or tissue distortion resulting in kinking and obstruction of the ureter [1, 3, 4]. The result is a varying degree of ureteral obstruction. The effect of obstruction results in increased ureteral pressure proximal to the point of obstruction, leading to elevated intrarenal pressures and transient change in renal function. Consequently, a decrease in GFR up to 4% of normal renal function can incur in the first 24 h after injury. The insult to renal function from such injuries leads to a transient increase in serum creatinine in the first 24 h until the contralateral kidney can adequately compensate for the compromised kidney. Irreversible injury to renal function can occur within 4–6 weeks after ureteral injury if undiagnosed and unrepaired [5]. Ureteral injury can manifest with a myriad of symptoms including fever, flank or groin pain, abdominal mass or urinary discharge from vagina; emergency department visit; admission to the hospital; and possibly unnecessary procedures to establish diagnosis. Complications include postoperative ileus, abscess formation, post-obstructive renal atrophy, fistula formation and ureteral stenosis. These, however, are delayed findings that indicate a progression of the initial ureteral injury that could have been avoided with a prompt diagnosis and resolution of the injury. In the present study, the null hypothesis was that changes in the serum creatinine levels were not associated with postoperative ureteral injury or obstruction. The objective was to determine the difference in serum creatinine level between the preoperative and the postoperative period and relate the difference to surgical outcome. The goal of the study was to obtain supporting data for the development of a simple inexpensive screening method to diagnose ureteral injury in the postoperative period and therefore prevent permanent damage and long-term complications.
Materials and methods Evaluation and selection of cases For this retrospective case control study, a chart review of all patients undergoing urogynecologic surgeries from October 2009 to June 2014 was done. IRB exempt status was obtained from the institution. The number of cases needed
13
Int Urol Nephrol
for each group was determined using the Kelsey calculation for unmatched sample size for case–control studies with 95% confidence, 80% power and proportion 1:4 case/control populations (OpenEpi.com, Open Source Epidemiologic Statistics for Public Health, Atlanta, GA). The calculation estimated a minimum of seven ureteral injury cases needed for the study. All surgeries were performed by two boardcertified female pelvic medicine and reconstructive surgeons at Loma Linda University Medical Center. Charts were evaluated for patient demographics, type of surgery done looking especially at urogynecologic procedures at high risk for ureteral injury, i.e., high uterosacral ligament suspension (HUSLS), robotic-assisted sacrocolpopexy (SCP) and abdominal sacrocolpopexy. Laboratory values were evaluated looking at pre- and postoperative findings, specifically serum creatinine levels before and after surgery. Imaging studies and other significant findings were reviewed, and any interventions were noted. Exclusion criteria included: missing data, co-surgeries involving other surgical departments and surgeries that varied significantly from the above-mentioned high-risk surgeries for ureteral injury. In this study, 3 cases were excluded due to missing data. There were no ureteral injuries in patients in the missing data group. Review of selected cases A total of 790 charts were reviewed, and 517 cases were excluded based on exclusion criteria (Fig. 1). The remaining 273 charts consisted of 230 HUSLS, 39 robotic sacrocolpopexies and 24 abdominal sacrocolpopexies. Among these cases, 7 undiagnosed ureteral injuries were identified. Indications for surgery primarily consisted of pelvic organ prolapse. Four of the 6 HUSLS cases were preceded by transvaginal hysterectomy. Cystoscopy was performed using the 70° lens in a systematic fashion. Intravenous fluorescein was administered and urine flow confirmed. All cases demonstrated normal bilateral ureteral flow during surgery before the patient left the operating room. Postoperative creatinine level was obtained within 24 h after surgery. Preoperative and postoperative serum creatinine levels were obtained with a significant increase in serum levels in all cases involving injury or obstruction. Ureteral injury was diagnosed with CT urogram with findings consistent with either no ureteral flow or reduced flow with or without extravasation in the distal ureter. The CT urograms were ordered following observations of increased serum creatinine after surgery. Identified obstructions were treated with ureteral stent placement with a resultant normalization of serum creatinine levels. One case involving vaginal hysterectomy with HUSLS demonstrated moderate flow from right ureter. Stent placement was unsuccessful, and therefore, patient underwent exploratory laparotomy displaying significant tissue distortion that resulted in obstructive ureteral kinking. Sutures were
Int Urol Nephrol Fig. 1 Diagram of the data collection process. Evaluation and selection of cases for the study
removed, the ureter was re-implanted into the bladder and a stent was placed. Subsequently, serum creatinine levels normalized. Controls were chosen in a similar and standardized fashion after consulting with an epidemiologist. Controls were obtained using a 1:4 ratio (case to control) from the eligible charts from October 2009 to June 2014. Controls were matched for type of surgery received and patient age at the time of surgery (Table 1). Absolute difference Δ between pre‑ and postoperative serum creatinine values Postoperative serum creatinine values were compared with preoperative levels and analyzed for net change and evaluated for any trends associated with complications, specifically ureteral injury or obstruction. The measurement endpoint was the change in serum creatinine levels from pre- to postoperative surgery. The measured endpoints determined for the cases with identified ureteral injuries were then compared with the level of change found in the control cases. Statistical analysis The changes in serum creatinine levels of the 2 groups (control cases versus ureteral injury cases) were presented as
Table 1 Retrospective case–control study of serum creatinine and the association with postoperative ureteral injury
No of cases (N) Age distribution (years) 20–54 55–64 65–74 75+ Patient age (years; mean ± standard deviation) Surgery type HUSLS SCP
Control group
Diagnosed postsurgery ureteral injury group
28
7
3 1 13 11 69.7 ± 10.2
0 1 3 3 69.7 ± 7.4
24 4
6 1
HUSLS high uterosacral ligament suspension, SCP robotic-assisted sacrocolpopexy
mean ± standard deviation. The mean of each group was compared using the Student’s two tailed t test statistics. Variances were tested using Hartley’s f test for equality of variance and found to be similar (OpenEpi.com, Open Source
13
Int Urol Nephrol
Epidemiologic Statistics for Public Health, Atlanta, GA). Statistical relevance was considered when p
UROLOGY - ORIGINAL PAPER
Perioperative serum creatinine changes and ureteral injury Sam Siddighi1,5 · Junchan J. Yune2 · Nicole B. Kwon1 · Jeffrey S. Hardesty1 · Joo H. Kim3 · Philip J. Chan4
Received: 10 May 2017 / Accepted: 5 August 2017 © Springer Science+Business Media B.V. 2017
Abstract Purpose To illustrate a simple method that screens for ureteral injury in the acute postoperative period after urogynecologic surgeries. Methods Serum creatinine measurements in the preoperative (baseline) and postoperative periods of urogynecologic surgeries were determined and the correlation of the change to ureteral injury and/or obstruction analyzed. The sample size calculation showed 7 cases and 28 controls were sufficient to detect significant changes in creatinine. Each of the seven cases was matched for age and type of surgery with a control patient in a 1:4 ratio following standard protocol. Results Chart review of patients (273 cases) undergoing urogynecologic surgeries from October 2009 to June 2014 were undertaken. There were 7 cases of ureteral injury and 28 matching control cases. All cases had intraoperative cystoscopy confirming bilateral ureteral flow. In the ureteral injury group, blockage of ureter was confirmed by CT scan
with IV contrast. There was a 59.8% increase in serum creatinine levels postoperative in the ureteral injury group versus a 3.8% decrease in controls. A difference of creatinine levels greater than or equal to 0.3 mg/dL over baseline was evident in ureteral injury cases. Conclusion A small change in serum creatinine level over baseline after urogynecologic surgery alerted the possibility of ureteral injury or obstruction. A simple and inexpensive evaluation of perioperative creatinine levels can promptly diagnose ureteral damage in the acute postoperative period for gynecologic reconstructive surgeries.
* Sam Siddighi [email protected]
2
Junchan J. Yune [email protected]
Urology Department, Loma Linda University School of Medicine, 11234 Anderson St., Coleman Suite 11105, Loma Linda, CA 92354, USA
3
Nicole B. Kwon [email protected]
Loma Linda University School of Medicine, 11234 Anderson St., Loma Linda, CA 92354, USA
4
Gynecology and Obstetrics Department, Loma Linda University School of Medicine, 11370 Anderson St., Suite 3950, Loma Linda, CA 92354, USA
5
11350 Anderson St., Suite 3900, Loma Linda, CA, USA
Jeffrey S. Hardesty [email protected] Joo H. Kim [email protected]
Keywords Creatinine · Ureter · Surgery injury · Urogynecology
Philip J. Chan [email protected] 1
Female Pelvic Medicine and Reconstructive Surgery, Loma Linda University School of Medicine, 11234 Anderson St., Coleman Suite 11105, Loma Linda, CA 92345, USA
13
Vol.:(0123456789)
Introduction Ureteral injury during gynecological surgery although uncommon is a complication that requires prompt diagnosis in order to avoid significant morbidity. The incidence of ureteral injury from pelvic reconstructive surgery ranges from 0.3 to 11% [1]. According to Doweling and colleagues, a reported 75% of iatrogenic ureteral injuries result from gynecological surgeries [2]. Ureteral injury occurs from direct or indirect damage via crush injury, ligation, transection of the ureter or tissue distortion resulting in kinking and obstruction of the ureter [1, 3, 4]. The result is a varying degree of ureteral obstruction. The effect of obstruction results in increased ureteral pressure proximal to the point of obstruction, leading to elevated intrarenal pressures and transient change in renal function. Consequently, a decrease in GFR up to 4% of normal renal function can incur in the first 24 h after injury. The insult to renal function from such injuries leads to a transient increase in serum creatinine in the first 24 h until the contralateral kidney can adequately compensate for the compromised kidney. Irreversible injury to renal function can occur within 4–6 weeks after ureteral injury if undiagnosed and unrepaired [5]. Ureteral injury can manifest with a myriad of symptoms including fever, flank or groin pain, abdominal mass or urinary discharge from vagina; emergency department visit; admission to the hospital; and possibly unnecessary procedures to establish diagnosis. Complications include postoperative ileus, abscess formation, post-obstructive renal atrophy, fistula formation and ureteral stenosis. These, however, are delayed findings that indicate a progression of the initial ureteral injury that could have been avoided with a prompt diagnosis and resolution of the injury. In the present study, the null hypothesis was that changes in the serum creatinine levels were not associated with postoperative ureteral injury or obstruction. The objective was to determine the difference in serum creatinine level between the preoperative and the postoperative period and relate the difference to surgical outcome. The goal of the study was to obtain supporting data for the development of a simple inexpensive screening method to diagnose ureteral injury in the postoperative period and therefore prevent permanent damage and long-term complications.
Materials and methods Evaluation and selection of cases For this retrospective case control study, a chart review of all patients undergoing urogynecologic surgeries from October 2009 to June 2014 was done. IRB exempt status was obtained from the institution. The number of cases needed
13
Int Urol Nephrol
for each group was determined using the Kelsey calculation for unmatched sample size for case–control studies with 95% confidence, 80% power and proportion 1:4 case/control populations (OpenEpi.com, Open Source Epidemiologic Statistics for Public Health, Atlanta, GA). The calculation estimated a minimum of seven ureteral injury cases needed for the study. All surgeries were performed by two boardcertified female pelvic medicine and reconstructive surgeons at Loma Linda University Medical Center. Charts were evaluated for patient demographics, type of surgery done looking especially at urogynecologic procedures at high risk for ureteral injury, i.e., high uterosacral ligament suspension (HUSLS), robotic-assisted sacrocolpopexy (SCP) and abdominal sacrocolpopexy. Laboratory values were evaluated looking at pre- and postoperative findings, specifically serum creatinine levels before and after surgery. Imaging studies and other significant findings were reviewed, and any interventions were noted. Exclusion criteria included: missing data, co-surgeries involving other surgical departments and surgeries that varied significantly from the above-mentioned high-risk surgeries for ureteral injury. In this study, 3 cases were excluded due to missing data. There were no ureteral injuries in patients in the missing data group. Review of selected cases A total of 790 charts were reviewed, and 517 cases were excluded based on exclusion criteria (Fig. 1). The remaining 273 charts consisted of 230 HUSLS, 39 robotic sacrocolpopexies and 24 abdominal sacrocolpopexies. Among these cases, 7 undiagnosed ureteral injuries were identified. Indications for surgery primarily consisted of pelvic organ prolapse. Four of the 6 HUSLS cases were preceded by transvaginal hysterectomy. Cystoscopy was performed using the 70° lens in a systematic fashion. Intravenous fluorescein was administered and urine flow confirmed. All cases demonstrated normal bilateral ureteral flow during surgery before the patient left the operating room. Postoperative creatinine level was obtained within 24 h after surgery. Preoperative and postoperative serum creatinine levels were obtained with a significant increase in serum levels in all cases involving injury or obstruction. Ureteral injury was diagnosed with CT urogram with findings consistent with either no ureteral flow or reduced flow with or without extravasation in the distal ureter. The CT urograms were ordered following observations of increased serum creatinine after surgery. Identified obstructions were treated with ureteral stent placement with a resultant normalization of serum creatinine levels. One case involving vaginal hysterectomy with HUSLS demonstrated moderate flow from right ureter. Stent placement was unsuccessful, and therefore, patient underwent exploratory laparotomy displaying significant tissue distortion that resulted in obstructive ureteral kinking. Sutures were
Int Urol Nephrol Fig. 1 Diagram of the data collection process. Evaluation and selection of cases for the study
removed, the ureter was re-implanted into the bladder and a stent was placed. Subsequently, serum creatinine levels normalized. Controls were chosen in a similar and standardized fashion after consulting with an epidemiologist. Controls were obtained using a 1:4 ratio (case to control) from the eligible charts from October 2009 to June 2014. Controls were matched for type of surgery received and patient age at the time of surgery (Table 1). Absolute difference Δ between pre‑ and postoperative serum creatinine values Postoperative serum creatinine values were compared with preoperative levels and analyzed for net change and evaluated for any trends associated with complications, specifically ureteral injury or obstruction. The measurement endpoint was the change in serum creatinine levels from pre- to postoperative surgery. The measured endpoints determined for the cases with identified ureteral injuries were then compared with the level of change found in the control cases. Statistical analysis The changes in serum creatinine levels of the 2 groups (control cases versus ureteral injury cases) were presented as
Table 1 Retrospective case–control study of serum creatinine and the association with postoperative ureteral injury
No of cases (N) Age distribution (years) 20–54 55–64 65–74 75+ Patient age (years; mean ± standard deviation) Surgery type HUSLS SCP
Control group
Diagnosed postsurgery ureteral injury group
28
7
3 1 13 11 69.7 ± 10.2
0 1 3 3 69.7 ± 7.4
24 4
6 1
HUSLS high uterosacral ligament suspension, SCP robotic-assisted sacrocolpopexy
mean ± standard deviation. The mean of each group was compared using the Student’s two tailed t test statistics. Variances were tested using Hartley’s f test for equality of variance and found to be similar (OpenEpi.com, Open Source
13
Int Urol Nephrol
Epidemiologic Statistics for Public Health, Atlanta, GA). Statistical relevance was considered when p
