Effect of Pre-operative Tizanidine on Postoperative Urinary Retention After Sacrospinous Vaginal Vault Suspension: a Pilot Study
Phase: PHASE3
Conditions: Postoperative Urinary Retention, Sacrospinous Vaginal Vault Suspension, Reconstructive Pelvic Surgery
Sponsor: Endeavor Health

Effect of pre-operative tizanidine on postoperative urinary retention after sacrospinous vaginal vault 
suspension: a pilot study 
  
Principal Investigator 
Claudia Paya Ten, MD 
 
Co-PI 
Angela Leffelman, MD 
 
Clinical Research Supervisor 
Ghazaleh Rostami, MD 
 
Sub-Investigator(s) 
Roger Goldberg, MD MPH 
Sonia Dutta, MD 
Adam Gafni-Kane, MD 
Ghazaleh Rostami, MD 
Henry Chill, MD 
  
Sponsor 
None 
  
Site of Investigation 
Northshore University Health System 
  
Date of Protocol:  6/4/2025 
 
Protocol Version:  1 

Purpose 
The purpose of this study is to evaluate the effect of tizanidine on postoperative urinary retention after 
sacrospinous vaginal vault suspension compared with baseline data. 
  
Background 
Postoperative urinary retention has been defined as the inability to void despite having fluid in the 
bladder during the postoperative period (1). Urinary retention after pelvic reconstructive surgery 
requiring indwelling catheter or self-catheterization usage occurs in approximately 30-60% of patients 
postoperatively (1,2,3). 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 (4). 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 overdistention, pain and urinary tract 
infection (5). 
 
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 (1,6). 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 (7). 
 
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 (8). 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 (9). Tizanidine also works as an alpha-adrenergic receptor 
blocker which can increase smooth muscle relaxation around the urethra specifically and, theoretically, 
improve urine flow (9). 
 
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% (7). Untreated acute postoperative pain has been shown to lead to increased morbidity and 
mortality (10). 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 (11,12). 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 (9). No study to date has evaluated preoperative 
administration of tizanidine for postoperative urinary retention. 
  
Hypothesis 
We hypothesize that providing tizanidine preoperatively will improve postoperative urinary retention 
rates compared with our previously defined baseline data. 
  
Objectives 
The primary objective of this study is to evaluate whether preoperative administration of tizanidine will 
decrease the rate of postoperative urinary retention sacrospinous vaginal vault suspension compared 
with previously defined data. The secondary objective of this study is to evaluate for any differences in 
postoperative pain after administration of tizanidine compared to previously defined data. 
  
Specific Aims 
1.  
Evaluate the postoperative urinary retention rate in patients undergoing sacrospinous 
ligament suspension after postoperative administration of tizanidine.  
2.  
Evaluate the postoperative pain scores after postoperative administration of tizanidine 
in patients undergoing sacrospinous vaginal vault suspension (postoperative nursing 
documentation performed in the recovery area based on a Likert scale of 0-10) and compare the 
differences in postoperative pain with previously collected data.  
3.  
Evaluate the difference in unplanned admission the day or surgery or unplanned 
admission within 30 days after surgery, unplanned office visits within 30 days after surgery or 
Northshore encounters within 30 days after surgery after postoperative administration of 
tizanidine. These medical encounters will include any need for additional medical treatment, 
phone calls, complications or patient concerns within 30 days postoperatively. This data will be 
collected via chart review. 
  
Outcome measures 
1.  
Primary outcome measure: 
a.           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. 
2.           Secondary outcome measures: 
a.           Determine differences in postoperative pain after postoperative administration of tizanidine. 
This data will be obtained by electronic data pull and chart review. 
b.           Determine the difference in unplanned admissions, office visits or Northshore encounters within 
30 days after surgery after postoperative administration of tizanidine. This data will be collected via 
chart review. 
  
Methods 
This is a prospective trial of patients who are undergoing sacrospinous ligament suspension with or 
without concomitant incontinence or pelvic reconstructive surgery with the Center for Pelvic Health at 
the Northshore University Health System.  
  

Women presenting to our tertiary urogynecology clinic with pelvic organ prolapse who decide to 
proceed with surgical treatment via a sacrospinous ligament suspension will be invited to participate in 
this study. This study will be discussed with the patient by their surgeon during their clinic initial 
screening visit or preoperative visit based on inclusion and exclusion criteria listed below. This study will 
involve no additional pre-operative tests or questionnaires, beyond our routine clinical pathway for 
women presenting with stress urinary incontinence. Written consent will be obtained.  
 
During the initial clinic visit or at a subsequent encounter prior to their surgery, patients will be provided 
information on the research study by their care provider and given the opportunity to ask any questions. 
Patients will then be given a consent form to take home and review, discuss with others and consider 
participation. At the second preoperative encounter, patients will have another opportunity to discuss 
the study and ask any questions to their care provider. At that point, patients will be given the 
opportunity to sign the consent form if they would like to participate in the study. Participation is 
voluntary. For patients who will not have a second preoperative clinic visit prior to surgery, during the 
initial clinic visit, the care provider will discuss the research study, provide a consent form to the patient 
to review and ask for permission from the patient to be contacted by a study team member. If 
permission is granted, a study team member will contact the patient via telephone to discuss the study 
further and allow for the patient to consider participation in the study and ask any questions. If at that 
time the patient decides to participate in the study, written consent will be obtained the morning of 
surgery. All consent documentation and research participation will be documented in the patient’s 
chart. 
  
Patients who are undergoing a sacrospinous ligament suspension will be enrolled (after the previously 
described informed consent discussion) to receive a single preoperative dose of tizanidine 2mg or in the 
preoperative holding area on the day of their scheduled surgery as well as continued tizanidine 
postoperatively as needed every 6 hours. 
  
After surgery, patients will then undergo a voiding trial in the recovery area. As described in prior 
studies, the patient will fail the voiding trial if voided volume is less than the PVR volume. Upon failing 
the voiding trial, the patient will be discharged home with a Foley catheter with plan for outpatient 
Foley catheter removal, consistent with our current protocol. According to our current protocol, patients 
discharged with a Foley catheter can either remove the catheter at home in 48-72 hours after surgery or 
call our office to have it removed at the next available appointment within 2-5 days postoperatively. 
  
We will then evaluate the rate of postoperative urinary retention after administration of tizanidine 
compared with our previously studied and documented postoperative urinary retention incidence after 
sacrospinous ligament. Any collected information will be de-identified. 
 
The current rate of postoperative urinary retention at our institution based on chart review after 
sacrospinous ligament suspension is 78.9%. Based on a sample size calculation to achieve 80% power, to 
evaluate for a 50% decrease in our urinary retention rate (from 78.9% to approximately 39.5%) we will 
need 23 subjects total. We aim to complete 23 subjects and expect to enroll 30 subjects to account for 
participant dropout. 
 
Postoperative pain data will be evaluated by reviewing postoperative pain scales documented by the 
nursing staff in the postoperative area on a Likert scale 0-10. We will also evaluate narcotic 
administration in the postoperative area as a proxy for pain. 
  
 

Inclusion criteria 
Sacrospinous ligament suspension (CPT 57282) 
  
Exclusion criteria 
Age <18 
Planned combined cases with colorectal surgery, general surgery, or gynecology-oncology 
Known history of urinary retention 
Known contraindication to tizanidine 
Concomitant use of the following: 
- 
Fluvoxamine, Ciprofloxacin (Patients are eligible if 3-5 half-lives have passed since they have 
taken Fluvoxamine, Ciprofloxacin) 
- 
Potent CYP1A2 inhibitors 
- 
Oral contraceptive 
- 
Alpha-adrenergic agonists  
Stage 4 Chronic Kidney Disease (eGFR <30), or worse  
Breastfeeding 
Hypersensitivity to tizanidine 
Pre-existing psychiatric illness  
Hypotension and chronic hypotension (<90/50 mmHg) 
  
Variables 
MRN 
Age (at time of surgery) 
Gravity and para 
Race/ethnicity 
Smoking status  
Menopausal status  
BMI 
Comorbid conditions  
          
Diabetes 
          
Hypertension 
          
Other cardiovascular disease  
          
Respiratory disease 
          
Obstructive sleep apnea 
          
Chronic pain conditions 
Prior hysterectomy  
Prior abdominal surgery  
History of prior prolapse surgery 
History of prior incontinence surgery 
Continence status 
Prolapse stage 
Location of surgery (Highland Park Hospital, Evanston) 
Type of anesthesia 
ASA grade 
Incontinence procedure 
Mid-urethral sling placement: CPT 57228 
Concomitant prolapse procedures 
Anterior colporrhaphy: CPT 57240 

Posterior colporrhaphy: CPT 57250 
Combined anterior and posterior colporrhaphy: CPT 57265 
 
Hysterectomy 
 
Rectopexy 
Intraoperative complications  
Additional procedures (ie. lysis of adhesions) 
Intraoperative consultations 
Length of procedure 
Estimated blood loss 
Surgeon  
Surgeon experience (< 5 years, > 5 years) 
Total time in PACU 
Time of day in ASU 
Total time in ASU 
Immediate postoperative complications 
Uncontrolled pain  
Postoperative pain scores upon admission to the ASU 
Postoperative pain scores at discharge 
Reason for postoperative admission (surgeon choice, comorbid conditions, nausea/vomiting, etc.) 
Time from voiding trial to void 
Postoperative urinary retention 
Postoperative urinary tract infection (UTI) 
Unanticipated healthcare encounters 
          
Urogynecology office visit (excluding voiding trial(s)) 
          
ED visit 
          
Readmission within 30 days of discharge 
          
Unplanned phone calls 
Complications 30 days after discharge 
          
Urinary tract infection 
          
Reoperation 
          
Venous thrombotic event   
  
Statistical Methodology 
A statistician from the NorthShore Research Institute will assist with statistical analysis. Data will be 
analyzed using SAS 9.4 (SAS Inc., Cary, NC). Demographic and clinical characteristics between groups will 
be compared using Student t-test (parametric) or Mann-Whitney U test (nonparametric) for continuous 
variables and Chi-squared test or Fisher exact test for categorical variables.  Multivariable logistic 
regression models will be constructed to examine the relationship of an outcome with demographic and 
clinical covariates. Statistical significance will be defined at p-value < 0.05. 
  
 
Literature review 
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