Transforaminal Lumbar Interbody Fusion SurgeryNCT06204900
A Post-marketing Study to Evaluate a Novel Surgical Monitoring Technique Using the EARP Nerve Cuff in TLIF Surgery.
A study testing Nerve Cuff and Retractor System in people with Transforaminal Lumbar Interbody Fusion Surgery, run by Retropsoas Technologies, LLC at 2 sites in United States.
Trial summary
The purpose of this study is to evaluate the differences (the effectiveness and the safety) between two different nerve and muscle monitoring devices currently available during a TLIF surgery. Read more about this study
- Who is it for?
- Ages 22 to 80 years
- Conditions the study is for
- Transforaminal Lumbar Interbody Fusion Surgery
- What is being tested?
- Nerve Cuff and Retractor System
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 5 participants
- Where
- 2 sitesUnited States
- Study dates
- 7 Jun 2024to 1 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 22 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Undergoing TLIF between L2-S1
Who cannot join
- Requiring TLIF surgery only at the L5-S1 level
- Acute lumbar spine trauma requiring immediate intervention
- Allergy or contraindication to propofol
- Lower extremity amputation
- Significant lower extremity edema noted on clinical exam
- Current treatment with chemotherapy, radiation, or immunosuppression
- Pregnant, or plans on becoming pregnant in the near future
- History of allergy to titanium, platinum, aluminum, stainless steel, or silicon
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Rothman Orthopaedic Institute
Philadelphia, Pennsylvania, 19107
Allegheny-Singer Research Institute
Pittsburgh, Pennsylvania, 15212
About this study
Official title: Evaluation Of A Novel Technique To Monitor Neurophysiological Activity During TLIF Surgery Using The Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and Retractor With A Commercially Available Lumbar Spine Retractor System
The purpose of this study is to evaluate the differences (the effectiveness and the safety) between two different nerve and muscle monitoring devices currently available during a TLIF surgery.
The Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and Retractor surgical and nerve monitoring tools will be used in addition to standard nerve monitoring tools during the surgery. The choice of standard nerve monitoring equipment is based on the decision of the surgeon and technologist and is not dictated by this study.
These tools will be compared with regards to safety and ability to accurately monitor the nervous system during the surgery.
Read the detailed description
The application of traditional SSEPs and tcMEPs to lumbar nerve root monitoring during TLIF surgery is both challenging and problematic. When applied to lumbar nerve root monitoring, SSEPs and tcMEPs unfortunately suffer in specificity, sensitivity, or both. A surgeon thus cannot confidently rely on these techniques to monitor nerve root function and must guess the likelihood of dysfunction.
Spontaneous EMG (sEMG) is also used to monitor nerve root activity. While sEMG is an excellent indicator of spinal nerve root manipulation, it is a poor diagnostic indicator of dysfunction. 90-95% of sEMG alerts are not associated with dysfunction yielding a high false positive rate and poor specificity, and postoperative deficits are often not associated with sEMG alerts yielding many false negatives and poor sensitivity. The primary utility of sEMG is to use as an indicator of manipulation, which prompts the acquisition of tcMEPs to assess function.
There is a clear need to take the guesswork out of monitoring the functional status of nerve roots at risk during lumbar decompressions and select interbody fusions. During TLIFs, the exiting nerve root is at risk as it courses obliquely across disc space encroaching on the surgical corridor. Standardly, a hand-held retractor is used to retract and protect the nerve root during disc space preparation, implant insertion or even simple decompression. This maneuver and retraction place a particular nerve root at risk, but again, traditional SSEP and tcMEPs are not ideal for monitoring that risk.
The EARP Nerve Cuff Electrode (Retropsoas Technologies) is a novel, Class II, device that is 510(k) cleared by FDA. It conducts electrical signals as a component of intraoperative neuromonitoring, is used with commercially available neuromonitoring systems, and does not stimulate or record the signal itself. The standard connectors at the proximal end interface with the neuromonitoring equipment. The distal nerve cuff electrode partially encircles and contacts the target nerve root. It uses a bipolar configuration to limit current spread. It is available in several inner diameters to accommodate variability in patient nerve root size anatomy.
The EARP Retractor is a Class I device used with a commercially available Retractor system and is only used as an additional 4th blade.
In TLIF surgery, the exiting nerve must be retracted to allow for sufficient access to the intervertebral disc space. The retraction is applied at the medial portion of the nerve root. The application of this retraction may produce activity in the nerve root and/or conduction changes in the nerve root due to temporary manipulation, compression, or ischemia related to the retraction.1
The objective of the study is to demonstrate the ability to safely monitor lumbar nerve root activity and function during retraction using an Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and an EARP Retractor system during a standard Transforaminal Lumbar Interbody Fusion (TLIF), with improved specificity and sensitivity over traditional monitoring techniques.
- Being tested
- Nerve Cuff and Retractor System
- Keywords
- TLIF Surgery
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nerve Cuff and Retractor SystemDevice
Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and an EARP Retractor system to safely monitor lumbar nerve root activity and function during a standard Transforaminal Lumbar Interbody Fusion (TLIF).
| Study group | Role | What they receive |
|---|---|---|
| Undergoing a single-level or two-level TLIF between L2-S1 | Experimental | During the surgery, the standard monitoring devices and the EARP monitoring study devices and techniques will be used. Receives: Device: Nerve Cuff and Retractor System |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of patients that experience an Adverse Device Effect (ADE)
Adverse device effect (ADE) - Adverse event (AE) judged by the clinician related to the use of an investigational devices. This includes any AE resulting from insufficient or inadequate instructions for use or the deployment, implantation, installation, or operation, or any malfunctioning of the investigational devices and any event resulting from use error or from unintentional misuse of the investigational devices.
Measured: From enrollment through the end of the follow-up assessment at week 6
Ability of EARP System to alert the surgeon to nerve irritation during surgery compared to standard IONM monitoring techniques
Signal amplitude at baseline, during initial retraction, and maintenance of retraction will be analyzed for changes using a 50% decrease as a surgeon alert. IONM assessments using traditional electrodes: SSEPs, tcMEPs and tfMEP. IONM assessments using EARP cuff: cuff SSEPs, cuff tcMEPs, and cuff tfMEPs.
Measured: During the TLIF surgery.
Secondary outcomes (3)
Evaluate the specificity and sensitivity of alerts to neurological deficits.
Evaluate the sensitivity and specificity of alerts to neurological deficits (by modality and overall). This will include neurological deficits noted on exams as well as a surrogate measure of deficit defined as an alert which resolves with relaxation of retraction.
Measured: From time of surgery through the end of the follow-up assessment at week 6
Assess monitorability of muscles/nerves
Compare the number of evaluable muscles during the surgery by modality and overall.
Measured: During the TLIF surgery.
Assess the change from baseline to end of surgery for each muscle and modality
Assess the lower extremity motor deficits post-surgery based on the ipsilateral lower extremity motor exam performed at Baseline, Post-Surgery, and at the 6-week follow-up visit.
Measured: From enrollment through the end of the follow-up assessment at week 6
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Jan 2024
- Study start7 Jun 2024
- Primary completion1 Dec 2025
- Study completion1 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Transforaminal Lumbar Interbody Fusion SurgeryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Lead sponsor
- Retropsoas Technologies, LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Nicholas Poulos, MD, Study director, Retropsoas Technologies, LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06204900
- Sponsor's protocol ID
- EARP-1-1001
- Status last verified
- Apr 2026
- First submitted
- 3 Jan 2024
- Last updated
- 13 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Individual participant data that underlie the results reported in publications, after deidentification (text, tables, figures, and appendices).
Study at a glance
From the registry record, last updated by the sponsor on 13 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation Of A Novel Technique To Monitor Neurophysiological Activity During TLIF Surgery Using The Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and Retractor With A Commercially Available Lumbar Spine Retractor System
- ClinicalTrials.gov ID
- NCT06204900
- Acronym / sponsor ID
- EARP-1-1001
- Keywords
- TLIF Surgery
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 5 participants (actual)
- Lead sponsor
- Retropsoas Technologies, LLCIndustry (pharma, biotech, devices)
- Study start
- 7 Jun 2024 (actual)
- Primary completion
- 1 Dec 2025 (actual)
- Study completion
- 1 Dec 2025 (actual)
- First posted
- 12 Jan 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to evaluate the differences (the effectiveness and the safety) between two different nerve and muscle monitoring devices currently available during a TLIF surgery.
The Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and Retractor surgical and nerve monitoring tools will be used in addition to standard nerve monitoring tools during the surgery. The choice of standard nerve monitoring equipment is based on the decision of the surgeon and technologist and is not dictated by this study.
These tools will be compared with regards to safety and ability to accurately monitor the nervous system during the surgery.
Detailed description
The application of traditional SSEPs and tcMEPs to lumbar nerve root monitoring during TLIF surgery is both challenging and problematic. When applied to lumbar nerve root monitoring, SSEPs and tcMEPs unfortunately suffer in specificity, sensitivity, or both. A surgeon thus cannot confidently rely on these techniques to monitor nerve root function and must guess the likelihood of dysfunction.
Spontaneous EMG (sEMG) is also used to monitor nerve root activity. While sEMG is an excellent indicator of spinal nerve root manipulation, it is a poor diagnostic indicator of dysfunction. 90-95% of sEMG alerts are not associated with dysfunction yielding a high false positive rate and poor specificity, and postoperative deficits are often not associated with sEMG alerts yielding many false negatives and poor sensitivity. The primary utility of sEMG is to use as an indicator of manipulation, which prompts the acquisition of tcMEPs to assess function.
There is a clear need to take the guesswork out of monitoring the functional status of nerve roots at risk during lumbar decompressions and select interbody fusions. During TLIFs, the exiting nerve root is at risk as it courses obliquely across disc space encroaching on the surgical corridor. Standardly, a hand-held retractor is used to retract and protect the nerve root during disc space preparation, implant insertion or even simple decompression. This maneuver and retraction place a particular nerve root at risk, but again, traditional SSEP and tcMEPs are not ideal for monitoring that risk.
The EARP Nerve Cuff Electrode (Retropsoas Technologies) is a novel, Class II, device that is 510(k) cleared by FDA. It conducts electrical signals as a component of intraoperative neuromonitoring, is used with commercially available neuromonitoring systems, and does not stimulate or record the signal itself. The standard connectors at the proximal end interface with the neuromonitoring equipment. The distal nerve cuff electrode partially encircles and contacts the target nerve root. It uses a bipolar configuration to limit current spread. It is available in several inner diameters to accommodate variability in patient nerve root size anatomy.
The EARP Retractor is a Class I device used with a commercially available Retractor system and is only used as an additional 4th blade.
In TLIF surgery, the exiting nerve must be retracted to allow for sufficient access to the intervertebral disc space. The retraction is applied at the medial portion of the nerve root. The application of this retraction may produce activity in the nerve root and/or conduction changes in the nerve root due to temporary manipulation, compression, or ischemia related to the retraction.1
The objective of the study is to demonstrate the ability to safely monitor lumbar nerve root activity and function during retraction using an Endoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and an EARP Retractor system during a standard Transforaminal Lumbar Interbody Fusion (TLIF), with improved specificity and sensitivity over traditional monitoring techniques.
Study design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Undergoing a single-level or two-level TLIF between L2-S1 | Experimental | Device: Nerve Cuff and Retractor SystemDuring the surgery, the standard monitoring devices and the EARP monitoring study devices and techniques will be used. |
Who may qualify
- Ages
- 22 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Undergoing TLIF between L2-S1
Key exclusion criteria (8 listed)
- Requiring TLIF surgery only at the L5-S1 level
- Acute lumbar spine trauma requiring immediate intervention
- Allergy or contraindication to propofol
- Lower extremity amputation
- Significant lower extremity edema noted on clinical exam
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Nerve Cuff and Retractor SystemEndoscopic Assisted Retropsoas (EARP) Nerve Cuff Electrode and an EARP Retractor system to safely monitor lumbar nerve root activity and function during a standard Transforaminal Lumbar Interbody Fusion (TLIF). | Device | Undergoing a single-level or two-level TLIF between L2-S1 |
Primary outcome
Number of patients that experience an Adverse Device Effect (ADE)
Time frame: From enrollment through the end of the follow-up assessment at week 6
Adverse device effect (ADE) - Adverse event (AE) judged by the clinician related to the use of an investigational devices. This includes any AE resulting from insufficient or inadequate instructions for use or the deployment, implantation, installation, or operation, or any malfunctioning of the investigational devices and any event resulting from use error or from unintentional misuse of the investigational devices.
Ability of EARP System to alert the surgeon to nerve irritation during surgery compared to standard IONM monitoring techniques
Time frame: During the TLIF surgery.
Signal amplitude at baseline, during initial retraction, and maintenance of retraction will be analyzed for changes using a 50% decrease as a surgeon alert. IONM assessments using traditional electrodes: SSEPs, tcMEPs and tfMEP. IONM assessments using EARP cuff: cuff SSEPs, cuff tcMEPs, and cuff tfMEPs.
3 secondary outcomes
Evaluate the specificity and sensitivity of alerts to neurological deficits.
Time frame: From time of surgery through the end of the follow-up assessment at week 6
Assess monitorability of muscles/nerves
Time frame: During the TLIF surgery.
Assess the change from baseline to end of surgery for each muscle and modality
Time frame: From enrollment through the end of the follow-up assessment at week 6
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Apr 2026.
- Individual participant dataSharing planned: Yes. Individual participant data that underlie the results reported in publications, after deidentification (text, tables, figures, and appendices).
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Nicholas Poulos, MD study director
Retropsoas Technologies, LLC
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nerve Cuff and Retractor System in people with Transforaminal Lumbar Interbody Fusion Surgery, run by Retropsoas Technologies, LLC at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of patients that experience an Adverse Device Effect (ADE) (time frame: From enrollment through the end of the follow-up assessment at week 6). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Apr 2026.