A Phase 3 interventional study of Tizanidine in Postoperative Urinary Retention, Sacrospinous Vaginal Vault Suspension and Reconstructive Pelvic Surgery, sponsored by Endeavor Health. Completed at 1 site in United States. Open to female participants aged 18 Years to 99 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-11-24.
Sponsored by Endeavor Health · Phase 3, Interventional, and Prevention
Postoperative urinary retention has been defined as the inability to void despite having fluid in the bladder during the postoperative period. Urinary retention after pelvic reconstructive surgery requiring indwelling catheter or self-catheterization usage occurs in approximately 30-60% of patients postoperatively. Our prior retrospective chart review reviewing postoperative urinary retention rates after pelvic reconstructive surgery demonstrated postoperative urinary retention after a sacrospinous vaginal vault suspension to be approximately 78.9%. Many women consider being discharged home with a Foley catheter to be a surgical complication and describe catheter use as the worst aspect of their surgery. Indwelling catheters are the leading cause of hospital-acquired urinary tract infections (UTIs), are often a source of embarrassment and inconvenience for patients, and often require additional office visits and healthcare utilization. Tizanidine is a muscle relaxant which can work to alleviate this spasm and, theoretically, prevent postoperative urinary retention. Tizanidine also works as an alpha-adrenergic receptor blocker which can increase smooth muscle relaxation around the urethra specifically and, theoretically, improve urine flow. Postoperative urinary retention is extremely common after pelvic reconstructive surgery involving a sacrospinous vaginal vault suspension and is extremely bothersome to patients. Tizanidine is a low-risk, well tolerated, cost-effective medication. No study to date has evaluated preoperative administration of tizanidine for postoperative urinary retention.
Postoperative urinary retention has been defined as the inability to void despite having fluid in the bladder during the postoperative period. Urinary retention after pelvic reconstructive surgery requiring indwelling catheter or self-catheterization usage occurs in approximately 30-60% of patients postoperatively. Our prior retrospective chart review reviewing postoperative urinary retention rates after pelvic reconstructive surgery demonstrated postoperative urinary retention after a sacrospinous vaginal vault suspension to be approximately 78.9%.
Each patient after surgery undergoes a "voiding trial" where their voided volume is compared to their post-void residual volume. "Passing" a voiding trial has traditionally been defined as voiding a greater volume than the post-void residual volume. If the patient does not "pass" the voiding trial, the patient is characterized as having postoperative urinary retention and is discharged home with an indwelling catheter to prevent detrusor injury from bladder over-distention, pain and urinary tract infection.
Many women consider being discharged home with a Foley catheter to be a surgical complication and describe catheter use as the worst aspect of their surgery. Indwelling catheters are the leading cause of hospital-acquired urinary tract infections (UTIs), are often a source of embarrassment and inconvenience for patients, and often require additional office visits and healthcare utilization.
The leading hypotheses regarding the incidence of postoperative urinary retention after sacrospinous ligament suspension includes postoperative pain and pelvic floor muscle spasm leading to retention. The sacrospinous suspension includes a suture that is passed through the sacrospinous ligament and, therefore, through the coccygeus muscle with irritation of the pudendal nerve. The pelvic floor is a synergistic team of muscles that work together to support the pelvic organs and spasm of the coccygeus muscle, rather than an isolated muscle, can cause spasm of the entirety of the pelvic floor leading to retention. Tizanidine is a muscle relaxant which can work to alleviate this spasm and, theoretically, prevent postoperative urinary retention. Tizanidine also works as an alpha-adrenergic receptor blocker which can increase smooth muscle relaxation around the urethra specifically and, theoretically, improve urine flow.
Tizanidine is also frequently given for postoperative pain after sacrospinous ligament suspension and may act as an adjunct to a non-narcotic pain regimen to improve postoperative pain while reducing narcotic use after surgery. Postoperative buttock and posterior thigh pain are common symptoms after SSLF, with immediate pain reported in 6-84% of patients and persistent pain at 6 weeks occurring in 1-15%. Untreated acute postoperative pain has been shown to lead to increased morbidity and mortality. Pain is the most common reason for a postoperative unplanned hospital admission and poor postoperative pain control can lead to decreased ambulation, increased incidence of thromboembolism, and decreased inspiratory effort leading to postoperative pneumonia, therefore postoperative pain control is critical. In a country with rising narcotic-use and dependence, it is critical that we continue to explore non-narcotic alternatives for patients after surgery.
Postoperative urinary retention is extremely common after pelvic reconstructive surgery involving a sacrospinous vaginal vault suspension and is extremely bothersome to patients. Tizanidine is a low-risk, well tolerated, cost-effective medication. No study to date has evaluated preoperative administration of tizanidine for postoperative urinary retention.
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Exclusion Criteria:
Tizanidine 2mg will be given preoperatively prior to scheduled sacrospinous ligament suspension
Drug: Tizanidine
Tizanidine 2mg will be given preoperatively prior to scheduled sacrospinous ligament suspension
Also known as: Zanaflex
Number of Participants With Postoperative Urinary Retention
Determine the postoperative urinary retention rates in patients undergoing a sacrospinous ligament suspension after postoperative administration of tizanidine. This will be determined immediately postoperative in the postoperative recovery room based on whether patients pass or fail their voiding trial described above. The result will be documented in electronic medical records and obtained from chart review.
Time frame: Immediate postoperative evaluation (1 day)
Average Postoperative Pain Score
Determine average postoperative pain score after postoperative administration of tizanidine utilizing a 10-point Likert scale for pain (0 = no pain, 10 = extreme pain). This data will be obtained by electronic data pull and chart review.
Time frame: Immediate postoperative evaluation (1 day)
Number of Participants With Postoperative Unanticipated Healthcare Encounters
Determine the number of participants with postoperative unanticipated healthcare encounters, including readmissions, office visits or emergency department visit within 30 days after surgery. This data will be collected via chart review.
Time frame: 30 days
| Milestone | Tizanidine |
|---|---|
| Started | 20 |
| Completed | 20 |
| Not completed | 0 |
Determine the postoperative urinary retention rates in patients undergoing a sacrospinous ligament suspension after postoperative administration of tizanidine. This will be determined immediately postoperative in the postoperative recovery room based on whether patients pass or fail their voiding trial described above. The result will be documented in electronic medical records and obtained from chart review.
| Participants | Tizanidine |
|---|---|
| Number of Participants With Postoperative Urinary Retention | 11 |
Determine average postoperative pain score after postoperative administration of tizanidine utilizing a 10-point Likert scale for pain (0 = no pain, 10 = extreme pain). This data will be obtained by electronic data pull and chart review.
| score on a scale | Tizanidine |
|---|---|
| Average Postoperative Pain Score | 3 ± 3 |
Determine the number of participants with postoperative unanticipated healthcare encounters, including readmissions, office visits or emergency department visit within 30 days after surgery. This data will be collected via chart review.
| Participants | Tizanidine |
|---|---|
| Number of Participants With Postoperative Unanticipated Healthcare Encounters | 1 |
Collected over 30 days. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Tizanidine | 0/20 (0%) | 0/20 (0%) | 0/20 (0%) |
| Age, Continuous(years) | Tizanidine |
|---|---|
| Mean | 69 ± 11 |
| Sex: Female, Male(Participants) | Tizanidine |
|---|---|
| Female | 20 |
| Male | 0 |
| Ethnicity (NIH/OMB)(Participants) | Tizanidine |
|---|---|
| Hispanic or Latino | 1 |
| Not Hispanic or Latino | 19 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | Tizanidine |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 0 |
| White | 19 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Smoking Status(Participants) | Tizanidine |
|---|---|
| Non-smoker | 14 |
| Prior smoker | 5 |
| Current smoker | 1 |
| Menopausal Status(Participants) | Tizanidine |
|---|---|
| Pre-menopausal | 1 |
| Post-menopausal | 19 |
| BMI(kg/m^2) | Tizanidine |
|---|---|
| Mean | 28 ± 7 |
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