CClinicalTrials.gg
CompletedNCT03444168Updated Mar 13, 2026Results posted

Central Nervous System Amplification in Lumbar Failed Back Surgery Syndrome

An observational study in Chronic Pain, sponsored by University of Kansas Medical Center. Completed at 1 site in United States. Open to participants aged 22 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-13.

Sponsored by University of Kansas Medical Center · Observational

Study type
Observational
Model
Cohort
Time perspective
Prospective
Enrollment
158
Ages
22 Years to 70 Years
Sex
All
01

Study summary

The purpose of this study is to learn whether or not certain risk factors and patient characteristics are linked with and possibly can predict the development of chronic pain after lumbar spine surgery.

02

Conditions studied

  • Chronic Pain

Keywords

  • lumbar spine surgery
  • lumbar failed back surgery syndrome
03

Who can participate

Ages eligible
22 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Non-probability sample

Study population

Participants will be recruited directly by the Candidate and by referral from specialist physicians at the KUMC Marc A. Asher, MD, Comprehensive Spine and Pain Management Center.

Eligibility criteria

Inclusion Criteria For All Participants:

  • Ability to read and speak English to allow for written informed consent, phenotyping, and patient-reported outcomes measures

Exclusion Criteria For All Participants:

  • Individuals receiving or applying for compensation or disability and other aspects associated with potential secondary gain
  • Inability to provide written informed consent
  • Severe physical impairment
  • Co-morbid medical conditions that may significantly impair physical functional status
  • Illicit drug or unreported opioid use
  • Medical or psychiatric conditions that in the judgment of study personnel would preclude participation in this study
  • Pregnant or nursing
  • Liver failure
  • Self-reported liver cirrhosis
  • Self-reported hepatitis
  • Severe Cardiovascular disease

Inclusion Criteria for Candidates for Lumbar Spine Surgery:

  • Deemed to be a candidate for primary lumbar spine surgery including but not limited to: lumbar laminectomy, discectomy, and fusion/instrumentation
  • Diagnostic clinical and radiographic findings including but not limited to: lumbar degenerative disc disease, lumbar disc protrusion, herniation, or extrusion, lumbar spondylosis, lumbar spinal stenosis, lumbar spondylolisthesis or spondylolysis
  • Willingness to participate in longitudinal follow-up or 6-months after their surgery.

Exclusion Criteria for Candidates for Lumbar Spine Surgery:

  • History of previous lumbar spine surgery
  • Indication for lumbar spine surgery is due to spinal cancer-related diagnosis
  • Need for urgent or emergent lumbar spine surgery

Inclusion Criteria for Candidates with Lumbar Failed Back Surgery Syndrome:

  • Chronic low back pain (+/- leg pain) for >= to 6 months duration after lumbar spine surgery (with or without instrumented fusion)
  • Low back pain severity is moderate to severe (Numerical Rating Scale [NRS] Score >=4)

Exclusion Criteria for Candidates with Lumbar Failed Back Surgery Syndrome:

  • Have a structural spinal lesion that would make them a current candidate for a revision lumbar spine surgery

Inclusion Criteria for Healthy Volunteers:

  • No major diseases or diagnoses influencing pain or function

Exclusion Criteria for Healthy Volunteers:

  • No chronic pain condition
  • Score 3 or greater on the 2011 FM Survey Criteria (i.e. individuals with very mild fatigue or sleep problems will be allowed to participate as this is extremely common in the general population)
04

Study design

Observational model
Cohort
Time perspective
Prospective
Enrollment
158 participants (actual)
Patient registry
No

Groups and cohorts

  • Candidate for Lumbar Spine Surgery

    Participants have been designated to be a candidate for lumbar spine surgery to treat chronic low back and/or leg pain and you have agreed to proceed with the surgery.

  • Lumbar Failed Back Surgery Syndrome

    Participants have been diagnosed with having lumbar failed back surgery syndrome and have persistent and moderate-to-severe low back and/or leg pain for more than 6 months after a lumbar spine surgery.

  • Healthy Volunteer

    Participants are a healthy volunteer wishing to participate in a research study.

05

What researchers measure

Primary outcomes

  1. Clinical Pain Severity - 50% Reduction Responders vs Nonresponders

    Measured by the Brief Pain Inventory (BPI). The BPI scores are a numerical rating scale and range from 0 to 10. A score of 0 is equal to no pain and a score of 10 is equal to pain as bad as you can imagine.

    Time frame: Change from Baseline to Month 6

  2. Fibromylagia-ness (FMness)

    2011 Fibromyalgia Survey score is calculated by combining the widespread pain index (WPI) and the Symptom Severity Scale (SSI) to derive a score from 0-31. Scores greater than or equal to 13 indicate a diagnosis of Fibromyalgia. Higher scores indicate the degree of central sensitization present in a given individual.

    Time frame: Baseline

  3. PROMIS T-score - Fatigue, Physical Function, Sleep-Related Impairment

    PROMIS measures to be included are Depression, Anxiety, Physical Functioning, Fatigue, Sleep Impairment, Emotional Support, and Social Participation. Each questionnaire usually has 4-16 response options ranging in value from one to five. The total raw score for a short form with all questions answered is the sum of the values of the response to each question. The total range of potential raw scores depends on the number of questions being asked, for example, a 6 item form would have a range from is 6 to 30. After the raw score is calculated, a T-score metric is used to convert the raw score to a T-score. On the T-score metric, a score of 50 is the mean of a relevant reference population and 10 is the standard deviation of that mean. For PROMIS measures, higher scores equals "more of the concept being measured", this could be a desirable or undesirable outcome, depending on the concept being measured.

    Time frame: Baseline

  4. PROMIS T-score - Anxiety, Depression, Emotional Support, Pain Interference, Satisfaction With Social Roles

    PROMIS measures to be included are Depression, Anxiety, Physical Functioning, Fatigue, Sleep Impairment, Emotional Support, and Social Participation. Each questionnaire usually has 4-16 response options ranging in value from one to five. The total raw score for a short form with all questions answered is the sum of the values of the response to each question. The total range of potential raw scores depends on the number of questions being asked, for example, a 6 item form would have a range from is 6 to 30. After the raw score is calculated, a T-score metric is used to convert the raw score to a T-score. On the T-score metric, a score of 50 is the mean of a relevant reference population and 10 is the standard deviation of that mean. For PROMIS measures, higher scores equals "more of the concept being measured", this could be a desirable or undesirable outcome, depending on the concept being measured.

    Time frame: Baseline

  5. Oswestry Disability Index

    The Oswestry Disability Index will be used to assess low back pain. There are 10 sections on the index. Each section has a possible score of 5. The total possible range of scores is 0 to 50. A score of 0 indicates no pain. A score of 50 indicates the person is bed-bound or exaggerating their symptoms.

    Time frame: Baseline

Secondary outcomes

  1. Coping Strategies Questionnaire - CAT

    A 6-item catastrophizing scale that measures ways to cope or deal with pain. Each item is scored on a scale of 0-6. Scores can range from 0-36, with the higher the score the higher the rate of catastrophizing.

    Time frame: Baseline

Other outcomes

  1. Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Trapezius

    Pressure pain sensitivity is measured by Algometry (measured at the trapezius and lumbar spine). It yields a pressure pain threshold value measured in kPA. Tests were performed at the Left and Right trapezius in triplicate at each site and the average is calculated and used for analysis.

    Time frame: Baseline

  2. Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Lower Back

    Pressure pain sensitivity is measured by Algometry (measured at the trapezius and lumbar spine). It yields a pressure pain threshold value measured in kPA.Tests were performed at the Left and Right lumbar spine in triplicate at each site and the average is calculated and used for analysis.

    Time frame: Baseline

  3. Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Multimodal Automated Sensory Testing

    Pressure pain sensitivity is measured by the Multimodal Automated Sensory Testing (MAST) System (measured at the thumbnail). It yields a pressure pain threshold value measured in kg/cm2. Thumb Pain30, Pain40, and Pain50 are the pressure intensities that provoke a pain rating of 30/100, 40/100, and 50/100, respectively. Thumb Pain Tolerance is the pressure intensity that provokes a response greater than or equal to 80/100.

    Time frame: Baseline

  4. Quantitative Sensory Testing (QST) - Conditioned Pain Modulation (CPM)

    Conditioned Pain Modulation as measured at the thumbnail using the MAST. It yields a numerical pain rating difference on a 0-100 numerical scale that can either be positive or negative called CPM magnitude. CPM magnitude will be calculated as the difference (post-pre) in the mean of the three pain ratings given to the test stimulus prior to the conditioning stimuli and the three pain ratings of the test stimulus given during the conditioning stimuli. A reduction in test stimulus rating by conditioning stimulation implies functional (inhibitory) CPM, and the degree of reduction expresses the efficiency of CPM.

    Time frame: Change from Post-stimulus test at Baseline visit to Pre-stimulus test at Baseline visit

06

Results

Posted Mar 13, 2026
Limitations and caveats
Trial was conducted during the start of COVID-19, which drastically impacted surgery number and selection.

Participant flow

Participant flow — Overall Study
MilestoneCandidate for Lumbar Spine SurgeryLumbar Failed Back Surgery SyndromeHealthy Volunteer
Started645440
Completed554940
Not completed950

Outcome measures

PrimaryClinical Pain Severity - 50% Reduction Responders vs Nonresponders

Measured by the Brief Pain Inventory (BPI). The BPI scores are a numerical rating scale and range from 0 to 10. A score of 0 is equal to no pain and a score of 10 is equal to pain as bad as you can imagine.

Time frame:
Change from Baseline to Month 6
Reported as:
Median · percentage of change
Clinical Pain Severity - 50% Reduction Responders vs Nonresponders
percentage of changeLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-Responders
Clinical Pain Severity - 50% Reduction Responders vs Nonresponders-83 (-100 to -62.5)0 (-12.5 to 15.5)
PrimaryFibromylagia-ness (FMness)

2011 Fibromyalgia Survey score is calculated by combining the widespread pain index (WPI) and the Symptom Severity Scale (SSI) to derive a score from 0-31. Scores greater than or equal to 13 indicate a diagnosis of Fibromyalgia. Higher scores indicate the degree of central sensitization present in a given individual.

Time frame:
Baseline
Reported as:
Count of participants · Participants
Fibromylagia-ness (FMness)
ParticipantsLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
FM Negative17272640
FM positive44230
PrimaryPROMIS T-score - Fatigue, Physical Function, Sleep-Related Impairment

PROMIS measures to be included are Depression, Anxiety, Physical Functioning, Fatigue, Sleep Impairment, Emotional Support, and Social Participation. Each questionnaire usually has 4-16 response options ranging in value from one to five. The total raw score for a short form with all questions answered is the sum of the values of the response to each question. The total range of potential raw scores depends on the number of questions being asked, for example, a 6 item form would have a range from is 6 to 30. After the raw score is calculated, a T-score metric is used to convert the raw score to a T-score. On the T-score metric, a score of 50 is the mean of a relevant reference population and 10 is the standard deviation of that mean. For PROMIS measures, higher scores equals "more of the concept being measured", this could be a desirable or undesirable outcome, depending on the concept being measured.

Time frame:
Baseline
Reported as:
Median · units on a scale
PROMIS T-score - Fatigue, Physical Function, Sleep-Related Impairment
units on a scaleLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Fatigue v1.0 8a58.80 (51.40 to 64.40)56.40 (48.10 to 61.50)62.40 (57.10 to 66.10)42 (33.10 to 47.70)
Physical Function v2.0 8b34.70 (31.80 to 36.30)35.30 (30.40 to 40.60)34.30 (32.00 to 36.30)60.10 (52.80 to 60.10)
Sleep-Related Impairment v1.0 8a60.90 (52.50 to 66.00)59.70 (50.50 to 62.90)62.30 (53.10 to 66.10)44.60 (38.40 to 50.30)
PrimaryPROMIS T-score - Anxiety, Depression, Emotional Support, Pain Interference, Satisfaction With Social Roles

PROMIS measures to be included are Depression, Anxiety, Physical Functioning, Fatigue, Sleep Impairment, Emotional Support, and Social Participation. Each questionnaire usually has 4-16 response options ranging in value from one to five. The total raw score for a short form with all questions answered is the sum of the values of the response to each question. The total range of potential raw scores depends on the number of questions being asked, for example, a 6 item form would have a range from is 6 to 30. After the raw score is calculated, a T-score metric is used to convert the raw score to a T-score. On the T-score metric, a score of 50 is the mean of a relevant reference population and 10 is the standard deviation of that mean. For PROMIS measures, higher scores equals "more of the concept being measured", this could be a desirable or undesirable outcome, depending on the concept being measured.

Time frame:
Baseline
Reported as:
Median · units on a scale
PROMIS T-score - Anxiety, Depression, Emotional Support, Pain Interference, Satisfaction With Social Roles
units on a scaleLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Anxiety v1.0 8a50.3 (44 to 61)49.8 (43.9 to 54.6)51.00 (45.90 to 60.10)43.35 (37.10 to 50.60)
Depression v1.0 8a54.5 (49.6 to 56.8)52.0 (38.2 to 56.9)54.00 (45.50 to 58.60)41.35 (38.20 to 49.60)
Emotional Support v2.0 4a52.1 (48.9 to 62)62.0 (48.9 to 62.0)56.20 (48.90 to 62.00)62.00 (48.90 to 62.00)
Pain Interference v2.0 8b66.9 (64.7 to 72.2)61.6 (58.4 to 70.1)66.20 (61.60 to 67.60)40.70 (40.70 to 40.70)
Satisfaction with Social Roles v1.0 4a37.5 (30.1 to 44.8)41.8 (30.1 to 51.8)37.40 (34.90 to 43.00)57.50 (51.80 to 63.70)
PrimaryOswestry Disability Index

The Oswestry Disability Index will be used to assess low back pain. There are 10 sections on the index. Each section has a possible score of 5. The total possible range of scores is 0 to 50. A score of 0 indicates no pain. A score of 50 indicates the person is bed-bound or exaggerating their symptoms.

Time frame:
Baseline
Reported as:
Median · units on a scale
Oswestry Disability Index
units on a scaleLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Oswestry Disability Index42 (32 to 54)40 (28 to 58)44 (38 to 56)1 (0 to 3)
SecondaryCoping Strategies Questionnaire - CAT

A 6-item catastrophizing scale that measures ways to cope or deal with pain. Each item is scored on a scale of 0-6. Scores can range from 0-36, with the higher the score the higher the rate of catastrophizing.

Time frame:
Baseline
Reported as:
Median · score on a scale
Coping Strategies Questionnaire - CAT
score on a scaleLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Coping Strategies Questionnaire - CAT8 (5 to 16)2 (0 to 12)8 (3 to 13)0.50 (0 to 4)
Other pre-specifiedQuantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Trapezius

Pressure pain sensitivity is measured by Algometry (measured at the trapezius and lumbar spine). It yields a pressure pain threshold value measured in kPA. Tests were performed at the Left and Right trapezius in triplicate at each site and the average is calculated and used for analysis.

Time frame:
Baseline
Reported as:
Median · kPA
Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Trapezius
kPALumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Left Trapezius287.2 (209.8 to 377.7)303.7 (208.3 to 352.3)227.3 (175.3 to 310.3)280.3 (212 to 368.7)
Right Trapezius299.7 (197.8 to 381.7)263.7 (171.7 to 349.0)251.5 (198.3 to 309.0)285.7 (213.3 to 331.0)
Other pre-specifiedQuantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Lower Back

Pressure pain sensitivity is measured by Algometry (measured at the trapezius and lumbar spine). It yields a pressure pain threshold value measured in kPA.Tests were performed at the Left and Right lumbar spine in triplicate at each site and the average is calculated and used for analysis.

Time frame:
Baseline
Reported as:
Median · kPA
Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Algometry - Lower Back
kPALumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Left Back342.3 (178.2 to 456.5)291.5 (196.7 to 341)221.3 (108.3 to 363.0)332.7 (297.0 to 403.7)
Right Back344.2 (188 to 437)328 (168.3 to 413)173.3 (145.7 to 318.3)321.0 (274.0 to 433.3)
Other pre-specifiedQuantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Multimodal Automated Sensory Testing

Pressure pain sensitivity is measured by the Multimodal Automated Sensory Testing (MAST) System (measured at the thumbnail). It yields a pressure pain threshold value measured in kg/cm2. Thumb Pain30, Pain40, and Pain50 are the pressure intensities that provoke a pain rating of 30/100, 40/100, and 50/100, respectively. Thumb Pain Tolerance is the pressure intensity that provokes a response greater than or equal to 80/100.

Time frame:
Baseline
Reported as:
Median · kg/cm^2
Quantitative Sensory Testing (QST) - Pressure Pain Sensitivity by Multimodal Automated Sensory Testing
kg/cm^2Lumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Thumb Pain303.86 (2.66 to 4.37)3.69 (2.72 to 5.33)3.0 (2.0 to 3.7)4.0 (3.1 to 5.0)
Thumb Pain404.60 (3.26 to 5.08)4.01 (2.74 to 5.88)3.6 (2.5 to 4.2)4.6 (3.7 to 5.4)
Thumb Pain505.35 (3.86 to 5.78)4.23 (3.31 to 6.52)4.0 (2.8 to 4.6)5.3 (4.1 to 5.9)
Thumb Pain Tolerance7.50 (5.65 to 7.89)4.98 (4.13 to 8.47)5.6 (4.8 to 6.2)6.6 (5.7 to 7.9)
Other pre-specifiedQuantitative Sensory Testing (QST) - Conditioned Pain Modulation (CPM)

Conditioned Pain Modulation as measured at the thumbnail using the MAST. It yields a numerical pain rating difference on a 0-100 numerical scale that can either be positive or negative called CPM magnitude. CPM magnitude will be calculated as the difference (post-pre) in the mean of the three pain ratings given to the test stimulus prior to the conditioning stimuli and the three pain ratings of the test stimulus given during the conditioning stimuli. A reduction in test stimulus rating by conditioning stimulation implies functional (inhibitory) CPM, and the degree of reduction expresses the efficiency of CPM.

Time frame:
Change from Post-stimulus test at Baseline visit to Pre-stimulus test at Baseline visit
Reported as:
Median · units on a scale
Quantitative Sensory Testing (QST) - Conditioned Pain Modulation (CPM)
units on a scaleLumbar Spine Surgery - RespondersLumbar Spine Surgery - Non-RespondersLumbar Failed Back Surgery SyndromeHealthy Volunteer
Quantitative Sensory Testing (QST) - Conditioned Pain Modulation (CPM)-3.33 (-13.33 to 1.67)-1.67 (-15 to 1.67)-5.0 (-15.0 to 0)-1.7 (-8.3 to 3.3)

Adverse events

Collected over AEs were assessed via pt-report or via EMR notification for the duration of the study, approximately 6 months.. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Lumbar Spine Surgery Candidates1/55 (1.8%)1/55 (1.8%)0/55 (0%)
Healthy Control Participants0/40 (0%)0/40 (0%)0/40 (0%)
Failed Back Surgery Syndrome Participants0/49 (0%)0/49 (0%)0/49 (0%)
Most frequent serious events
Most frequent serious events
EventLumbar Spine Surgery CandidatesHealthy Control ParticipantsFailed Back Surgery Syndrome Participants
DeathGeneral disorders1/55——

Baseline characteristics

Age, Continuous
Age, Continuous(years)Candidate for Lumbar Spine SurgeryLumbar Failed Back Surgery SyndromeHealthy VolunteerTotal
Median55 (45 to 64)53 (44 to 61)52 (42 to 61)54 (43 to 62)
Sex: Female, Male
Sex: Female, Male(Participants)Candidate for Lumbar Spine SurgeryLumbar Failed Back Surgery SyndromeHealthy VolunteerTotal
Female32332186
Male23161958
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Candidate for Lumbar Spine SurgeryLumbar Failed Back Surgery SyndromeHealthy VolunteerTotal
Hispanic or Latino2237
Not Hispanic or Latino534737137
Unknown or Not Reported0000
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)Candidate for Lumbar Spine SurgeryLumbar Failed Back Surgery SyndromeHealthy VolunteerTotal
Race — White504237129
Race — Black, African American4318
Race — American Indian, Alaskan0101
Race — Asian0112
Race — Native Hawaiian or Pacific Islander1001
Race — Other, Unknown0213
07

Study locations

1 site
  • University of Kansas Medical Center
    Kansas City, Kansas 66160, United States
08

References and documents

Study documents

  • Protocol and statistical analysis plan · Aug 25, 2020

Documents are hosted by the registry — open the source record to download them.

09

Registry details

Key details

Study ID
NCT03444168
Lead sponsor
University of Kansas Medical Center
Collaborators
National Institute of General Medical Sciences (NIGMS)
Responsible party
Sponsor
First posted
Feb 23, 2018
Start date
Jun 29, 2018
Primary completion
Apr 20, 2023
Completion
Apr 20, 2023
Results posted
Mar 13, 2026
Last update
Mar 13, 2026

Study contacts

Andrea Chadwick, MD
principal investigator · University of Kansas Medical Center

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
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