Objective
We sought to determine age-adjusted rates (AARs) of lower urinary tract injury and incidence in selected inpatient gynecologic and obstetric procedures.
Study Design
We utilized the National Hospital Discharge Survey, 1979–2006. AARs of nonobstetric bladder and ureteral injuries and incidence of lower urinary tract injury for various hysterectomy types and deliveries were calculated for women >18 years old.
Results
Overall AARs of ureteral injury decreased from 0.06–0.03 per 1000 women (1979–2006). AARs of inpatient gynecologic procedures decreased from 24.9–11.8 per 1000 women (1979–2006). By hysterectomy type, bladder injury was highest in laparoscopic-assisted vaginal hysterectomy (VH) (13.8 per 1000) and VH (13.1 per 1000). Ureteral injury recognized during hysterectomy was most common with radical hysterectomy (7.7 per 1000) and least common with laparoscopic-assisted VH (0 per 1000).
Conclusion
Ureteral injuries at time of inpatient surgical procedures have decreased from 1979–2006. This corresponds with a sharp decrease in inpatient gynecologic procedures.
Lower urinary tract (LUT) injury is a potentially devastating complication of gynecologic and obstetric procedures. Bladder and ureteral injury may be associated with significant short-term and long-term morbidity, including increased initial operative time, return to the operating room for subsequent procedures, need for prolonged indwelling catheter drainage, urinary tract infection, fistula formation, and loss of renal function. Urinary tract injury may also lead to socioeconomic sequelae, including temporary or permanent loss of employment, anxiety, depression, and deterioration of interpersonal relationships. Physicians involved in gynecologic surgery resulting in urinary tract injury may experience significant personal and financial costs related to the high relative risk of litigation.
The incidence of LUT injury at time of gynecologic surgery and obstetric procedures has been poorly studied. Based on systematic review of benign gynecologic surgery, estimated rates of bladder injury associated with hysterectomy ranged from 0.3–6.0 per 1000 surgeries, and ureteral injury ranged from 0.2–7.3 per 1000 surgeries. The estimated rate of bladder injury associated with other gynecologic or urogynecologic surgery was 11.2 per 1000 surgeries, and the rate of ureteral injury was 2.2 per 1000 surgeries. The data regarding the risk of urinary tract injury at time of obstetric procedures are also limited. Case-control data demonstrate an incidence of bladder injury of 0.28% at time of cesarean delivery.
The primary objective of this study was to determine age-adjusted rates (AARs) of nonobstetric LUT injury in the United States from 1979–2006. Secondarily, we sought to determine the incidence of LUT injury among women undergoing selected inpatient gynecologic and obstetric procedures. LUT injury associated with various types of hysterectomy was calculated. The incidence of bladder and urethral injury at time of spontaneous vaginal delivery, operative vaginal delivery, and cesarean delivery was determined.
Materials and Methods
The National Hospital Discharge Survey (NHDS) is a federal dataset compiled by the National Center for Health Statistics. This dataset is a national probability sample of nonfederal short-stay hospitals in the United States based on approximately 270,000 inpatient records acquired from 466 hospitals annually. The overall dataset error rate for final diagnoses and procedures is 1.0% and 0.7%, respectively.
University of Pittsburgh Institutional Review Board exempt status was obtained. Using International Classification of Diseases, Ninth Revision, Clinical Modification ( ICD-9-CM ) procedure codes, this dataset was used to identify women who sustained bladder injuries (obstetric and nonobstetric) and ureteral injuries. ICD-9-CM procedure codes were also used to estimate the annual number of inpatient gynecologic procedures, 1979–2006.
Women who sustained a bladder and/or ureteral injury at time of hysterectomy were identified using ICD-9-CM procedure codes for nonobstetric bladder and/or ureteral injury ( Table 1 ) and hysterectomy. Hysterectomy types included: subtotal abdominal hysterectomy (SAH) (68.3, 68.39), laparoscopic supracervical hysterectomy (LSH) (68.31), total abdominal hysterectomy (TAH) (68.4), vaginal hysterectomy (VH) (68.5, 68.59), laparoscopic-assisted VH (LAVH) (68.51), and radical abdominal hysterectomy (RAH) (68.6).
| Variable | Procedure name | ICD-9-CM procedure code |
|---|---|---|
| Obstetric bladder and urethral injury | Repair of current obstetric laceration of bladder and urethra | 75.61 |
| Nonobstetric bladder injury | Suture of laceration of bladder | 57.81 |
| Closure of cystotomy | 57.82 | |
| Other repair of bladder | 57.89 | |
| Ureteral injury | Ureteroneocystostomy | 56.74 |
| Transureteroureterostomy | 56.75 | |
| Other anastomosis or bypass of ureter | 56.79 | |
| Suture of laceration of ureter | 56.82 | |
| Closure of ureterostomy | 56.83 | |
| Closure of other fistula of ureter | 56.84 | |
| Urethropexy | 56.85 | |
| Removal of ligature from ureter | 56.86 | |
| Other repair of ureter | 56.89 |
Similarly, women who sustained a bladder injury at time of delivery were identified. Deliveries were classified as spontaneous vaginal, operative vaginal (forceps assisted and vacuum assisted), or cesarean. Both diagnosis and procedure codes were used to identify deliveries to reflect a change in coding practices in the late 1980s that favored the use of procedure codes. Obstetric bladder injuries also include urethral injuries, since 1 ICD-9-CM code exists for this type of injury ( Table 1 ).
To determine disease classes associated with nonobstetric bladder and ureteral injuries, ICD-9-CM diagnosis codes were used. The NHDS dataset contains up to 7 diagnosis codes. Only the primary (first) diagnosis code was considered in this analysis.
Incidence of bladder and ureteral injury and obstetric bladder/urethral injury was calculated for various hysterectomy types and delivery types, respectively. AARs for bladder injuries, ureteral injuries, inpatient gynecologic procedures, and cesarean delivery were calculated using 1990 census data for women >18 years of age. For accuracy, age adjustment and frequencies were calculated for each year, 1979–2006. Population-weighting ratio adjustments were performed according to the NHDS study design. Linear regression was used to assess trends in bladder (obstetric and nonobstetric) and ureteral injury rates over the study time period. Statistical analysis was performed using software (SPSS, version 17.0; SPSS, Inc, Chicago, IL). Statistical significance was evaluated at the P < .05 level.
Results
During the study period, AARs of inpatient gynecologic procedures decreased from 35.2 per 1000 women (1979) to 11.9 per 1000 women (2006) ( P < .001). AARs of ureteral injury per 1000 women decreased from 0.06 (1979) to 0.03 (2006) ( P < .001). AARs of nonobstetric bladder injury per 1000 women varied from 0.13 (1979) to 0.05 (2006) ( P = .11) ( Figure 1 ). In 2006, 64% of ureteral injuries recognized at the time of surgery were associated with nongynecologic procedures ( Figure 2 ). In contrast, 87% of nonobstetric bladder injuries in 2006 recognized at the time of surgery were associated with gynecologic procedures ( Figure 3 ).
