Intraoperative Neuromonitoring of Sacral Reflexes to Predict Post Operative Function in Patients Undergoing Sacrectomy for Pelvic Bone Malignancy or Patients Undergoing Spinal Procedures Without Sacral Root Involvement

Phase 2a Prospective Study of Intraoperative Neuromonitoring of the Bulbocavernosus and External Urethral Sphincter Reflexes

This clinical trial tests how well monitoring the sacral reflexes during surgery (intraoperatively) works to predict the post operative function for patients undergoing removal of the lowest part of the spine (sacrectomy) for pelvic bone cancers or patients undergoing spinal procedures. These surgical procedures can lead to damage to sacral root nerves which can result in impairment to the lower extremities, bowel, bladder, and sexual function. Intraoperative monitoring of sacral reflexes can provide objective, real-time information about pelvic nerve function during surgery. This can aid surgical decision-making and help surgeons better prepare patients to understand the changes that may have occurred to their function as a result of surgery. Intraoperative neuromonitoring may work well to predict postoperative function in patients undergoing sacrectomy for pelvic bone malignancy or patients undergoing spinal procedures.

Study Overview

• Status: Not yet recruiting
• Conditions: Metastatic Malignant Neoplasm in the Bone; Bone Neoplasm
• Intervention / Treatment: Other: Survey Administration; Procedure: Surgical Procedure; Procedure: Intraoperative Nerve Monitoring

Detailed Description

PRIMARY OBJECTIVE:

I. To evaluate the feasibility of acquiring analyzable sacral reflex neuromonitoring data at baseline and case closure during surgery.

SECONDARY OBJECTIVES:

I. To characterize sacral reflex parameters amplitude, latency, waveform morphology, and Nerveana Power Index (NPI) at baseline under standardized intraoperative neuromonitoring conditions in patients undergoing spinal procedures without sacral nerve root involvement and patients undergoing sacrectomy.

II. To describe intraoperative changes in sacral reflex parameters from baseline to end-of-case during standardized intraoperative neuromonitoring in patients undergoing sacrectomy.

III. To characterize the relative contribution of individual sacral nerve roots to sacral reflex responses during intraoperative stimulation in patients undergoing sacrectomy.

IV. To characterize longitudinal changes in postoperative functional outcomes in patients undergoing sacrectomy.

EXPLORATORY OBJECTIVES:

I. To explore the association between intraoperative sacral reflex changes and postoperative functional outcomes in patients undergoing sacrectomy.

II. To explore the association between sacrifice of higher- versus lower-contributing sacral nerve roots and postoperative functional outcomes in patients undergoing sacrectomy.

OUTLINE:

Patients undergo neuromonitoring of the sacral reflexes at predefined time points during standard of care surgery.

After completion of study treatment, patients are followed up at 21 days, 6 weeks and 3, 6 and 12 months.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Duarte, California, United States, 91010
      • City of Hope Medical Center
      • Contact: Alana M. Munger; Phone Number: 808-384-0975; Email: amunger@coh.org
      • Principal Investigator: Alana M. Munger

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Documented informed consent of the participant and/or legally authorized representative.

  • Assent, when appropriate, will be obtained per institutional guidelines
• Age: ≥ 18 years
• Ability to complete study questionnaires
• Willingness to comply with all study procedures, including postoperative patient-reported outcome (PRO) assessments

• Undergoing surgery at City of Hope involving either:

  • Complete or partial sacrectomy for primary or metastatic bone tumors, or
  • Thoracolumbar intervention in which the sacral roots are not exposed or manipulated (reference cohort)

Exclusion Criteria:

• Prior sacrectomy or prior surgery resulting in complete sacral nerve transection
• For thoracolumbar cohort patients, prior diagnosis or patient report of bowel or bladder dysfunction
• Cognitive or psychiatric conditions preventing reliable completion of PRO instruments

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Diagnostic (Intraoperative neuromonitoring); Patients undergo neuromonitoring of the sacral reflexes at predefined time points during standard of care surgery.

Other: Survey Administration; Ancillary studies; Procedure: Surgical Procedure; Undergo standard of care surgery; Other Names: Operation; Surgery; Surgery Type; Surgical; Surgical Intervention; Surgical Interventions; Surgical Procedures; Type of Surgery; Surgery, NOS; Procedure: Intraoperative Nerve Monitoring; Undergo intraoperative neuromonitoring; Other Names: IONM; Intraoperative Neuromonitoring; Intraoperative Neurophysiological Monitoring

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Reproducible and interpretable bulbocavernosus reflex (BCR) and external urethral sphincter (EUS) reflex responses (feasibility)	Reproducible is defined as the ability to elicit a reflex response on repeated stimulation with consistent waveform presence and morphology at a given timepoint. Interpretable is defined as a recorded reflex response that is distinguishable from background noise and artifact and permits determination of response presence or absence and measurement of latency and amplitude. A two-sided 95% Clopper-Pearson confidence interval will be provided as a measure of precision.	From baseline, Up to 1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distribution of BCR reflex parameters	Amplitude, latency, frequency distribution, etc, measured via intraoperative neuromonitoring (IONM). ), Analyses will first be conducted separately within thoracolumber and sacrectomy patient groups. Descriptive statistics will be reported for BCR for each group. Next, to compare the mean values between the two groups, t-test or Mann-Whitney U-test will be implemented depending on the distribution of these parameters. Additionally, within the sacrectomy group, the changes of these parameters from baseline to the end-of-case will be assessed either through paired t-test or Wilcoxon's signed rank test, depending on the distribution of each parameter.	From baseline, Up to 1 year
Distribution of EUS reflex parameters	Amplitude, latency, frequency distribution, etc, measured via IONM. Analyses will first be conducted separately within thoracolumber and sacrectomy patient groups. Descriptive statistics will be reported for EUS for each group. Next, to compare the mean values between the two groups, t-test or Mann-Whitney U-test will be implemented depending on the distribution of these parameters. Additionally, within the sacrectomy group, the changes of these parameters from baseline to the end-of-case will be assessed either through paired t-test or Wilcoxon's signed rank test, depending on the distribution of each parameter.	From baseline, Up to 1 year
Change in BCR reflex parameters	Analyses will first be conducted separately within thoracolumber and sacrectomy patient groups. Descriptive statistics will be reported for BCR for each group. Next, to compare the mean values between the two groups, t-test or Mann-Whitney U-test will be implemented depending on the distribution of these parameters. Additionally, within the sacrectomy group, the changes of these parameters from baseline to the end-of-case will be assessed either through paired t-test or Wilcoxon's signed rank test, depending on the distribution of each parameter.	From baseline, Up to 1 year
Change in EUS reflex parameters	Analyses will first be conducted separately within thoracolumber and sacrectomy patient groups. Descriptive statistics will be reported for EUS for each group. Next, to compare the mean values between the two groups, t-test or Mann-Whitney U-test will be implemented depending on the distribution of these parameters. Additionally, within the sacrectomy group, the changes of these parameters from baseline to the end-of-case will be assessed either through paired t-test or Wilcoxon's signed rank test, depending on the distribution of each parameter.	From baseline, Up to 1 year
Relative contribution of individual right sacral nerve roots to BCR amplitude	Amplitudes among sacrectomy patients will be descriptively reported.	During intraoperative stimulation, Up to Day 21
Relative contribution of individual left sacral nerve roots to BCR amplitude	Amplitudes among sacrectomy patients will be descriptively reported.	During intraoperative stimulation, Up to Day 21
Relative contribution of individual right sacral nerve roots to EUS amplitude	Amplitudes among sacrectomy patients will be descriptively reported.	During intraoperative stimulation, Up to Day 21
Relative contribution of individual left sacral nerve roots to EUS amplitude	Amplitudes among sacrectomy patients will be descriptively reported.	During intraoperative stimulation, Up to Day 21
Bowel function scores	Assessed by Memorial Sloan Kettering Bowel Function Instrument. Will be described by graphs and descriptive statistics at each time point.	From baseline, Up to 1 year
Bladder function scores	Assessed by International Consultation on Incontinence Questionnaire. Will be described by graphs and descriptive statistics at each time point.	From baseline, up to 1 year
Sexual function scores	Assessed by Female Sexual Function Index (female patients only) and International Index of Erectile Function (male patients only). Will be described by graphs and descriptive statistics at each time point.	From baseline, up to 1 year
Lower extremity function	Assessed by Toronto Extremity Salvage Score for the Lower Extremity. Will be described by graphs and descriptive statistics at each time point.	From baseline, up to 1 year
Quality of life	Assessed by Functional Assessment of Cancer Therapy-General. Will be described by graphs and descriptive statistics at each time point.	From baseline, up to 1 year
Postoperative urologic function	Assessed by post-void residual (PVR) or cystometry. Will be described by graphs and descriptive statistics at each time point.	From baseline, up to 1 year

Collaborators and Investigators

• Sponsor: City of Hope Medical Center
• Collaborators: National Cancer Institute (NCI)
• Investigators: Principal Investigator: Alana M Munger, City of Hope Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): January 10, 2027
• Primary Completion (Estimated): June 10, 2029
• Study Completion (Estimated): June 10, 2029

Study Registration Dates

• First Submitted: July 10, 2026
• First Submitted That Met QC Criteria: July 10, 2026
• First Posted (Actual): July 16, 2026

Study Record Updates

• Last Update Posted (Actual): July 16, 2026
• Last Update Submitted That Met QC Criteria: July 10, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Neoplasms by Site; Neoplasms; Bone Neoplasms; Diagnostic Techniques and Procedures; Diagnosis; Monitoring, Physiologic; Monitoring, Intraoperative; Neurophysiological Monitoring; Surgical Procedures, Operative; Intraoperative Neurophysiological Monitoring
• Other Study ID Numbers: 25826 (Other Identifier: City of Hope Medical Center); P30CA033572 (U.S. NIH Grant/Contract); NCI-2026-04599 (Registry Identifier: CTRP (Clinical Trial Reporting Program))

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No