SPINE Volume 39, Number 22, pp 1905-1909 ©2014, Lippincott Williams & Wilkins
SURGERY
Patient and Surgical Factors Associated With Postoperative Urinary Retention After Lumbar Spine Surgery Sapan D. Gandhi, MD,* Shyam A. Patel, BS,† Mitchell Maltenfort, PhD,‡ David Greg Anderson, MD,‡ Alexander R. Vaccaro, MD, PhD,‡ Todd J. Albert, MD,‡ and Jeffrey A. Rihn, MD‡
Study Design. Retrospective case series. Objective. The objectives of this study were to (1) determine the rate of postoperative urinary retention (POUR) in a series of patients undergoing lumbar spine surgery, (2) compare length of hospital stay between patients who developed POUR and patients who did not, and (3) identify the patient and surgical factors associated with the development of POUR. Summary of Background Data. Although POUR is a common complication in many surgical subspecialties, sparse literature is present regarding development of POUR after posterior lumbar surgical procedures. Methods. A retrospective review was conducted of all posterior lumbar surgery cases performed at single institute from July 2008 to July 2012. Data collected included demographic variables (age, sex, body mass index), length of stay, comorbid medical conditions, and surgical data. The Wilcoxon rank sum test with continuity correction was used to compare length of hospital stay between patients who developed POUR and patients who did not. A multivariate logistic regression model was created using all patient and surgical factors and systematically pruned of variables not improving overall predictive power. Results. A total of 647 patients (291 decompression, 356 decompression and fusion) were included in the study. Of 647 patients, 36 had urinary retention after lumbar spine surgery (5.6%). Patients who developed POUR had a longer length of stay than patients who did not develop POUR (3.94 d vs. 2.34 d;
From the *Department of Orthopaedics, William Beaumont Health System, Royal Oak, MI; †Drexel University College of Medicine, Philadelphia, PA; and ‡Department of Orthopaedics, Thomas Jefferson University Hospital, The Rothman Institute, Philadelphia, PA. Acknowledgment date: March 4, 2014. First revision date: June 23, 2014. Acceptance date: July 28, 2014. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. Relevant financial activities outside the submitted work: board membership, consultancy, employment, grants, royalties, stocks. Address correspondence and reprint requests to Sapan D. Gandhi, MD, Department of Orthopaedics, 3601 W. 13 Mile Rd, Royal Oak, MI 48073; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000572 Spine
P = 0.005). Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with development of POUR (odds ratio = 3.05, 9.82, 1.04, 3.32, and 2.51, respectively). Smoking was inversely associated with the development of POUR (odds ratio = 0.45). Conclusion. The risk of developing POUR after posterior lumbar spine surgery is approximately 5%. Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with the POUR group. Patients who developed POUR had a greater length of hospital stay. Key words: postoperative urinary retention, lumbar spine, spine surgery, spine surgery complications, postoperative complications, lumbar fusion, lumbar decompression, postoperative urinary function, postoperative urinary catheterization, lumbar fusion complication, lumbar decompression complication. Level of Evidence: 4 Spine 2014;39:1905–1909
P
ostoperative urinary retention (POUR) is common after operative procedures and anesthesia: reported rates range from 5% to 70%.1,2 The wide variation in reported rates is most likely attributed to differences in patient populations considered and types of procedures studied.2 POUR can cause patient discomfort and dissatisfaction, increase lengths of hospital stay, and increase total costs, especially if POUR is allowed to lead to overdistention of the bladder.1–3 Permanent damage of the detrusor muscle can significantly contribute to long-term morbidity.4 In the setting of orthopedic surgery, POUR predisposes patients to longer hospital stays, increased discomfort from bladder distension and catheterization, urinary tract infection, and possible urosepsis.5,6 The relationship between orthopedic procedures and urinary retention has been best described in patients undergoing total hip and knee arthroplasty. Retention after total hip arthroplasty has a reported incidence of 28%, with risk factors including epidural morphine, an older age, and hypertension.7,8 POUR after total knee arthroplasty has a reported incidence ranging from 8% to 19.7%.5,6,9 Reported risk factors include male sex, epidural analgesia, older age, history of urinary retention, and hypertension.5,6,8 www.spinejournal.com
1905
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140326_LR 1905
14/09/14 11:46 AM
SURGERY The literature is still sparse regarding patient factors involved in the development of POUR after lumbar spine surgery. Information related to factors involved with POUR would allow surgeons to better identify patients at risk, better inform patients of the risk of POUR, and possibly avoid the associated complications of urinary tract infection and deep sepsis in patients who develop POUR. Furthermore, management strategies can be altered to modify the incidence of POUR in high-risk patients, ultimately decreasing morbidity and unnecessary costs.3 The purpose of this study was to (1) determine the incidence of POUR after posterior lumbar spine surgery, (2) determine whether there is an increased length of hospital stay associated with POUR, and (3) identify any patient and surgical factors associated with the development of POUR after posterior lumbar spine surgery.
MATERIALS AND METHODS After institutional review board approval of the research protocol, a retrospective review of all posterior lumbar spine surgical procedures performed by the primary investigator from July 2008 to July 2012 was conducted (N = 647). The reviewed cases consisted entirely of lumbar decompression, posterior lumbar decompression and fusion, and transforaminal lumbar interbody fusion. Patient age, sex, body mass index, medical comorbidities, tobacco use, prior lumbar spine surgery, type of surgery performed (lumbar decompression vs. posterior lumbar decompression and fusion vs. transforaminal lumbar interbody fusion), use of rh-BMP2, number of operative levels, American Society of Anesthesiologists physical status classification, estimated blood loss, intraoperative and postoperative blood transfusion, intraoperative complications, and development of POUR were recorded for each surgery. Specifically, medical comorbid conditions included in the study were diabetes mellitus, hypertension, coronary artery disease, obesity, depression, benign prostatic hyperplasia (BPH), chronic obstructive pulmonary disease, and obstructive sleep apnea. Development of POUR was defined as documented patient inability to void requiring catheterization, a postvoid residual volume of greater than 300 mL, or diagnosis of POUR by urology consultation in the hospital in the absence of available documentation verifying other criteria. A Foley catheter was immediately inserted in patients who were identified to have POUR. The Wilcoxon rank sum test with continuity correction was used to compare length of hospital stay between patients who developed POUR and patients who did not (R Foundation for Statistical Computing, Vienna, Austria). A multivariate logistical regression model was performed using “rms” package in the R statistical language (R Foundation for Statistical Computing). A full model was created using all variables and was then systematically pruned of variables that did not improve model predictive power.
RESULTS A total of 647 consecutive patients during a 4-year period by a single surgeon were included in this study. Of 647 patients, 1906
www.spinejournal.com
Urinary Retention After Lumbar Surgery • Gandhi et al
36 had urinary retention after lumbar spine surgery (5.6%). The mean age of patients included in the study was 55.7 years (SD) = 14.6 yr; range, 18–89 yr). The series consisted of 51.5% males (n = 333) versus 48.5% females (n = 314). The average body mass index of the series was 30.5 (SD = 6.5; range, 16–55). Of the 647 patients included in the study, 356 patients underwent a lumbar fusion (posterior lumbar decompression and fusion: n = 178; transforaminal lumbar interbody fusion: n = 178) whereas 291 patients underwent a posterior lumbar decompression. The indications to undergo fusion in this series of patients were primarily degenerative spondylolisthesis, isthmic spondylolisthesis, recurrent disc herniation, and/or degenerative scoliosis that had failed conservative treatment. The indications to undergo lumbar decompression were symptomatic degenerative spinal stenosis and/or disc herniation that had failed conservative treatment. The number of levels decompressed or fused was 1 level (58.4%; n = 378), 2 levels (32.4%; n = 210), 3 levels (7.4%; n = 48), and 4 levels (1.5%; n = 10). The overall average length of hospital stay for the entire series was 2.4 days (SD = 2.2 d; range, 0–32 d). The Wilcoxon rank sum test with continuity correction was used to compare lengths of hospital stay between groups. The length of hospital stay of patients who developed POUR compared with patients who did not develop POUR was longer (3.9 d vs. 2.3 d; W = 8066; P = 0.005). A multivariate logistical regression model using the “rms” package in the R statistical language (R Foundation for Statistical Computing) was applied. A full model was created using all patient and surgical variables. Subsequently, the full model was systematically pruned of variables and a final model with only variables contributing to the accuracy of the model was created. Male sex, BPH, age, diabetes, depression, and tobacco use were included in the final logistic regression model (Table 1). BPH was associated with the development of POUR (odds ratio [OR] = 9.82; 95% confidence interval [CI], 3.22–29.95; P < 0.0001). In addition, male sex (OR = 3.05; 95% CI, 1.25–7.46; P = 0.015), age (OR = 1.04 per year; 95% CI, 1.01–1.07; P = 0.017), diabetes (OR = 3.32; 95% CI, 1.52–7.26; P = 0.003), and depression (OR = 2.51; 95% CI, 1.07–5.89; P = 0.035) were associated with the development of POUR and were included in the final model. Tobacco use decreased the odds of developing POUR (OR = 0.45; 95% CI, 0.21–0.95; P = 0.036). Body mass index, hypertension, coronary artery disease, American Society of Anesthesiologists class, prior lumbar surgery, type of lumbar surgery, number of operative levels, dural tear, operative time, and estimated blood loss were not associated with the development of POUR and were not included in the final model (P > 0.05).
DISCUSSION POUR is common after anesthesia and operative procedures and can cause patient discomfort and dissatisfaction, increase lengths of hospital stay, and increase total costs, especially if POUR is allowed to lead to overdistention of the bladder.1,2,10 October 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140326_LR 1906
14/09/14 11:46 AM
SURGERY
Urinary Retention After Lumbar Surgery • Gandhi et al
TABLE 1. Summary of Final Model of Patient Factors Related to POUR after Lumbar Spine Surgery Odds Ratio
95% Confidence Interval
P
Male (no BPH)
3.05
1.25–7.46
0.015
BPH
9.82
3.22–29.95
SURGERY
Patient and Surgical Factors Associated With Postoperative Urinary Retention After Lumbar Spine Surgery Sapan D. Gandhi, MD,* Shyam A. Patel, BS,† Mitchell Maltenfort, PhD,‡ David Greg Anderson, MD,‡ Alexander R. Vaccaro, MD, PhD,‡ Todd J. Albert, MD,‡ and Jeffrey A. Rihn, MD‡
Study Design. Retrospective case series. Objective. The objectives of this study were to (1) determine the rate of postoperative urinary retention (POUR) in a series of patients undergoing lumbar spine surgery, (2) compare length of hospital stay between patients who developed POUR and patients who did not, and (3) identify the patient and surgical factors associated with the development of POUR. Summary of Background Data. Although POUR is a common complication in many surgical subspecialties, sparse literature is present regarding development of POUR after posterior lumbar surgical procedures. Methods. A retrospective review was conducted of all posterior lumbar surgery cases performed at single institute from July 2008 to July 2012. Data collected included demographic variables (age, sex, body mass index), length of stay, comorbid medical conditions, and surgical data. The Wilcoxon rank sum test with continuity correction was used to compare length of hospital stay between patients who developed POUR and patients who did not. A multivariate logistic regression model was created using all patient and surgical factors and systematically pruned of variables not improving overall predictive power. Results. A total of 647 patients (291 decompression, 356 decompression and fusion) were included in the study. Of 647 patients, 36 had urinary retention after lumbar spine surgery (5.6%). Patients who developed POUR had a longer length of stay than patients who did not develop POUR (3.94 d vs. 2.34 d;
From the *Department of Orthopaedics, William Beaumont Health System, Royal Oak, MI; †Drexel University College of Medicine, Philadelphia, PA; and ‡Department of Orthopaedics, Thomas Jefferson University Hospital, The Rothman Institute, Philadelphia, PA. Acknowledgment date: March 4, 2014. First revision date: June 23, 2014. Acceptance date: July 28, 2014. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. Relevant financial activities outside the submitted work: board membership, consultancy, employment, grants, royalties, stocks. Address correspondence and reprint requests to Sapan D. Gandhi, MD, Department of Orthopaedics, 3601 W. 13 Mile Rd, Royal Oak, MI 48073; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000572 Spine
P = 0.005). Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with development of POUR (odds ratio = 3.05, 9.82, 1.04, 3.32, and 2.51, respectively). Smoking was inversely associated with the development of POUR (odds ratio = 0.45). Conclusion. The risk of developing POUR after posterior lumbar spine surgery is approximately 5%. Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with the POUR group. Patients who developed POUR had a greater length of hospital stay. Key words: postoperative urinary retention, lumbar spine, spine surgery, spine surgery complications, postoperative complications, lumbar fusion, lumbar decompression, postoperative urinary function, postoperative urinary catheterization, lumbar fusion complication, lumbar decompression complication. Level of Evidence: 4 Spine 2014;39:1905–1909
P
ostoperative urinary retention (POUR) is common after operative procedures and anesthesia: reported rates range from 5% to 70%.1,2 The wide variation in reported rates is most likely attributed to differences in patient populations considered and types of procedures studied.2 POUR can cause patient discomfort and dissatisfaction, increase lengths of hospital stay, and increase total costs, especially if POUR is allowed to lead to overdistention of the bladder.1–3 Permanent damage of the detrusor muscle can significantly contribute to long-term morbidity.4 In the setting of orthopedic surgery, POUR predisposes patients to longer hospital stays, increased discomfort from bladder distension and catheterization, urinary tract infection, and possible urosepsis.5,6 The relationship between orthopedic procedures and urinary retention has been best described in patients undergoing total hip and knee arthroplasty. Retention after total hip arthroplasty has a reported incidence of 28%, with risk factors including epidural morphine, an older age, and hypertension.7,8 POUR after total knee arthroplasty has a reported incidence ranging from 8% to 19.7%.5,6,9 Reported risk factors include male sex, epidural analgesia, older age, history of urinary retention, and hypertension.5,6,8 www.spinejournal.com
1905
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140326_LR 1905
14/09/14 11:46 AM
SURGERY The literature is still sparse regarding patient factors involved in the development of POUR after lumbar spine surgery. Information related to factors involved with POUR would allow surgeons to better identify patients at risk, better inform patients of the risk of POUR, and possibly avoid the associated complications of urinary tract infection and deep sepsis in patients who develop POUR. Furthermore, management strategies can be altered to modify the incidence of POUR in high-risk patients, ultimately decreasing morbidity and unnecessary costs.3 The purpose of this study was to (1) determine the incidence of POUR after posterior lumbar spine surgery, (2) determine whether there is an increased length of hospital stay associated with POUR, and (3) identify any patient and surgical factors associated with the development of POUR after posterior lumbar spine surgery.
MATERIALS AND METHODS After institutional review board approval of the research protocol, a retrospective review of all posterior lumbar spine surgical procedures performed by the primary investigator from July 2008 to July 2012 was conducted (N = 647). The reviewed cases consisted entirely of lumbar decompression, posterior lumbar decompression and fusion, and transforaminal lumbar interbody fusion. Patient age, sex, body mass index, medical comorbidities, tobacco use, prior lumbar spine surgery, type of surgery performed (lumbar decompression vs. posterior lumbar decompression and fusion vs. transforaminal lumbar interbody fusion), use of rh-BMP2, number of operative levels, American Society of Anesthesiologists physical status classification, estimated blood loss, intraoperative and postoperative blood transfusion, intraoperative complications, and development of POUR were recorded for each surgery. Specifically, medical comorbid conditions included in the study were diabetes mellitus, hypertension, coronary artery disease, obesity, depression, benign prostatic hyperplasia (BPH), chronic obstructive pulmonary disease, and obstructive sleep apnea. Development of POUR was defined as documented patient inability to void requiring catheterization, a postvoid residual volume of greater than 300 mL, or diagnosis of POUR by urology consultation in the hospital in the absence of available documentation verifying other criteria. A Foley catheter was immediately inserted in patients who were identified to have POUR. The Wilcoxon rank sum test with continuity correction was used to compare length of hospital stay between patients who developed POUR and patients who did not (R Foundation for Statistical Computing, Vienna, Austria). A multivariate logistical regression model was performed using “rms” package in the R statistical language (R Foundation for Statistical Computing). A full model was created using all variables and was then systematically pruned of variables that did not improve model predictive power.
RESULTS A total of 647 consecutive patients during a 4-year period by a single surgeon were included in this study. Of 647 patients, 1906
www.spinejournal.com
Urinary Retention After Lumbar Surgery • Gandhi et al
36 had urinary retention after lumbar spine surgery (5.6%). The mean age of patients included in the study was 55.7 years (SD) = 14.6 yr; range, 18–89 yr). The series consisted of 51.5% males (n = 333) versus 48.5% females (n = 314). The average body mass index of the series was 30.5 (SD = 6.5; range, 16–55). Of the 647 patients included in the study, 356 patients underwent a lumbar fusion (posterior lumbar decompression and fusion: n = 178; transforaminal lumbar interbody fusion: n = 178) whereas 291 patients underwent a posterior lumbar decompression. The indications to undergo fusion in this series of patients were primarily degenerative spondylolisthesis, isthmic spondylolisthesis, recurrent disc herniation, and/or degenerative scoliosis that had failed conservative treatment. The indications to undergo lumbar decompression were symptomatic degenerative spinal stenosis and/or disc herniation that had failed conservative treatment. The number of levels decompressed or fused was 1 level (58.4%; n = 378), 2 levels (32.4%; n = 210), 3 levels (7.4%; n = 48), and 4 levels (1.5%; n = 10). The overall average length of hospital stay for the entire series was 2.4 days (SD = 2.2 d; range, 0–32 d). The Wilcoxon rank sum test with continuity correction was used to compare lengths of hospital stay between groups. The length of hospital stay of patients who developed POUR compared with patients who did not develop POUR was longer (3.9 d vs. 2.3 d; W = 8066; P = 0.005). A multivariate logistical regression model using the “rms” package in the R statistical language (R Foundation for Statistical Computing) was applied. A full model was created using all patient and surgical variables. Subsequently, the full model was systematically pruned of variables and a final model with only variables contributing to the accuracy of the model was created. Male sex, BPH, age, diabetes, depression, and tobacco use were included in the final logistic regression model (Table 1). BPH was associated with the development of POUR (odds ratio [OR] = 9.82; 95% confidence interval [CI], 3.22–29.95; P < 0.0001). In addition, male sex (OR = 3.05; 95% CI, 1.25–7.46; P = 0.015), age (OR = 1.04 per year; 95% CI, 1.01–1.07; P = 0.017), diabetes (OR = 3.32; 95% CI, 1.52–7.26; P = 0.003), and depression (OR = 2.51; 95% CI, 1.07–5.89; P = 0.035) were associated with the development of POUR and were included in the final model. Tobacco use decreased the odds of developing POUR (OR = 0.45; 95% CI, 0.21–0.95; P = 0.036). Body mass index, hypertension, coronary artery disease, American Society of Anesthesiologists class, prior lumbar surgery, type of lumbar surgery, number of operative levels, dural tear, operative time, and estimated blood loss were not associated with the development of POUR and were not included in the final model (P > 0.05).
DISCUSSION POUR is common after anesthesia and operative procedures and can cause patient discomfort and dissatisfaction, increase lengths of hospital stay, and increase total costs, especially if POUR is allowed to lead to overdistention of the bladder.1,2,10 October 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140326_LR 1906
14/09/14 11:46 AM
SURGERY
Urinary Retention After Lumbar Surgery • Gandhi et al
TABLE 1. Summary of Final Model of Patient Factors Related to POUR after Lumbar Spine Surgery Odds Ratio
95% Confidence Interval
P
Male (no BPH)
3.05
1.25–7.46
0.015
BPH
9.82
3.22–29.95
