Trial Outcomes & Findings for Study Evaluating the Safety and Effectiveness of the FLEXUS(TM) Interspinous Spacer (NCT NCT01156675)

Last Updated: 2018-06-01

Results Overview

Change in the Zurich Claudication Questionnaire (ZCQ) score at 24 months compared with the score at baseline as follows: * Change of \>0.5 points in Physical Function on a scale of 1-4 points (lower values are considered a better outcome) * Change of \>0.5 points in Symptom Severity on a scale of 1-5 points (lower values are considered a better outcome) * Satisfaction of \<2.5 points on a scale of 1-4 points (lower values are considered a better outcome) The Zurich Claudication Questionnaire is a three part form that quantifies severity of symptoms, physical function characteristics, and patient's satisfaction after treatment.

Recruitment status

TERMINATED

Study phase

Target enrollment

215 participants

Primary outcome timeframe

24 months

Results posted on

2018-06-01

Participant Flow

Participant milestones

Participant milestones
Measure	FLEXUS™ Interspinous Spacer FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Overall Study STARTED	107	106	2
Overall Study COMPLETED	73	81	0
Overall Study NOT COMPLETED	34	25	2

Reasons for withdrawal

Reasons for withdrawal
Measure	FLEXUS™ Interspinous Spacer FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Overall Study Death	5	3	0
Overall Study No data	29	22	2

Baseline Characteristics

Study Evaluating the Safety and Effectiveness of the FLEXUS(TM) Interspinous Spacer

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	FLEXUS™ Interspinous Spacer n=107 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=106 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the X-STOP® Spacer	No Treatment n=2 Participants Not treated with FLEXUS or X-STOP	Total n=215 Participants Total of all reporting groups
Age, Continuous	68.2 years STANDARD_DEVIATION 8.93 • n=5 Participants	67.3 years STANDARD_DEVIATION 8.88 • n=7 Participants	71.5 years STANDARD_DEVIATION 4.95 • n=5 Participants	67.8 years STANDARD_DEVIATION 8.87 • n=4 Participants
Sex: Female, Male Female	54 Participants n=5 Participants	46 Participants n=7 Participants	1 Participants n=5 Participants	101 Participants n=4 Participants
Sex: Female, Male Male	53 Participants n=5 Participants	60 Participants n=7 Participants	1 Participants n=5 Participants	114 Participants n=4 Participants
Race/Ethnicity, Customized Race · Caucasian	98 Participants n=5 Participants	102 Participants n=7 Participants	2 Participants n=5 Participants	202 Participants n=4 Participants
Race/Ethnicity, Customized Race · Black	7 Participants n=5 Participants	3 Participants n=7 Participants	0 Participants n=5 Participants	10 Participants n=4 Participants
Race/Ethnicity, Customized Race · Asian	1 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	1 Participants n=4 Participants
Race/Ethnicity, Customized Race · Hispanic	1 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	1 Participants n=4 Participants
Race/Ethnicity, Customized Race · Other	0 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	1 Participants n=4 Participants
Weight (lbs)	181.8 lbs STANDARD_DEVIATION 33.87 • n=5 Participants	193.2 lbs STANDARD_DEVIATION 37.75 • n=7 Participants	195.0 lbs STANDARD_DEVIATION 77.78 • n=5 Participants	187.5 lbs STANDARD_DEVIATION 36.45 • n=4 Participants
Height (inches)	67.0 inches STANDARD_DEVIATION 3.62 • n=5 Participants	67.2 inches STANDARD_DEVIATION 3.94 • n=7 Participants	66.0 inches STANDARD_DEVIATION 11.31 • n=5 Participants	67.1 inches STANDARD_DEVIATION 3.84 • n=4 Participants

PRIMARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed is not consistent with numbers provided in the Participant Flow module. The discrepancy in the numbers is due to an additional subject having ZCQ data at 24 months in the FLEXUS arm and one less subject with ZCQ data at 24 months in the X-STOP group. No data was collected for the "No Treatment" arm.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=74 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=80 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Number of Participants With Less Pain/Disability Using the Zurich Claudication Questionnaire (ZCQ) Score	42 Participants	50 Participants	0 Participants

PRIMARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed is not consistent with numbers in the Participant Flow module. The discrepancy is due to two less subjects having neurologic status data at 24 months in the FLEXUS arm and one less subject with neurologic status data at 24 months in the X-STOP arm. No data was collected for the "No Treatment" arm.

Neurological status is based on four types of measurement parameters: motor, sensory, reflexes, and special assessments. Each parameter will be coded as follows: Motor 0 Total Paralysis 1. Palpable or Visible Contraction 2. Active Movement, Gravity Eliminated 3. Active Movement, Against Gravity 4. Active Movement, Against Some Resistance 5. Active Movement, Against Full Resistance Sensory 0 Absent 1. Impaired 2. Normal Reflexes 0 Absent or Trace 1. Hyper-reflexic 2. Normal or hypo-reflexic Straight Leg Raise 0 0°-70° (abnormal) 1 \>70°-90° (normal) If all evaluations for the parameter are determined to be normal, then the parameter is given a normal status. If any evaluations for the parameter are abnormal, then the parameter is given an abnormal status. The overall neurological status will be considered a success if and only if all the four parameters are stable or improved.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=71 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=80 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Number of Participants With a Successful Neurologic Status	60 Participants	69 Participants	0 Participants

PRIMARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed in the FLEXUS arm and X-STOP arm is the number of subjects who started the Study in the respective arm. No data was collected for the "No Treatment" arm.

Measures the number of participants who did not have another surgery for treatment of lumbar spinal stenosis at the same spinal level that was originally treated. Data, including adverse events, were monitored, evaluated and assessed for evidence of additional surgical treatment at the spinal level that was originally treated.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=107 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=106 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Number of Participants With no Additional Surgery for Lumbar Spinal Stenosis at the Spinal Level That Was Treated	90 Participants	99 Participants	0 Participants

PRIMARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed in the FLEXUS arm and X-STOP arm is the number of subjects who started the Study in the respective arms. No data was collected for the "No Treatment" arm.

Absence of implant-related complications, including device dislodgement, defined as: * Failure of implant material (e.g. fracture); * Implant migration outside of the interspinous space (posteriorly beyond the posterior margin of the spinous processes, anteriorly within the spinal canal, or laterally more than half of the implant width); or * Other complications that can be specifically associated with the implanted device.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=107 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=106 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Number of Participants With an Absence of Implant-related Complications	84 Participants	97 Participants	0 Participants

SECONDARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed is not consistent with numbers in the Participant Flow module. The discrepancy is due to ten less subjects having ODI data at 24 months in the FLEXUS arm and four less subject with ODI data at 24 months in the X-STOP arm. No data was collected for the "No Treatment" arm.

The Oswestry Disability Index (ODI) questionnaire contains ten topics concerning intensity of pain, lifting, ability to care for oneself, ability to walk, ability to sit, sexual function, ability to stand, social life, sleep quality, and ability to travel. Each topic is followed by 6 statements describing different potential scenarios in the patient's life relating to the topic. The subject chooses the statement which most closely resembles their situation. Each question is scored on a scale of 0-5 with the first statement being zero and indicating the least amount of disability and the last statement is scored 5 indicating most severe disability. Scores for all questions answered are summed, then multiplied by two to obtain the index (range 0 to 100). Zero is equated with no disability and 100 is the maximum disability.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=63 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=77 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Mean Oswestry Disability Index (ODI) at 24 Months	19.2 score Standard Deviation 17.97	17.4 score Standard Deviation 14.15	—

SECONDARY outcome

Timeframe: 24 months

The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with "no pain" on the left border and "as severe as it could be" on the right border. The subject is instructed to make a mark along the line to represent the intensity of back pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=62 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=77 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Mean Visual Analog Scale (VAS) - Back Pain at 24 Months	20.2 millimeters Standard Deviation 27.77	18.8 millimeters Standard Deviation 27.36	—

SECONDARY outcome

Timeframe: 24 months

Population: The Overall Number of Participants Analyzed is not consistent with numbers in the Participant Flow module. The discrepancy is due to eleven less subjects having VAS data at 24 months in the FLEXUS arm and four less subject with VAS data at 24 months in the X-STOP arm. No data was collected for the "No Treatment" arm.

The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with "no pain" on the left border and "as severe as it could be" on the right border. The subject is instructed to make a mark along the line to represent the intensity of right leg pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=62 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=77 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Mean Visual Analog Scale (VAS) - Right Leg Pain at 24 Months	16.2 millimeters Standard Deviation 26.72	9.2 millimeters Standard Deviation 15.77	—

SECONDARY outcome

Timeframe: 24 months

The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with "no pain" on the left border and "as severe as it could be" on the right border. The subject is instructed to make a mark along the line to represent the intensity of left leg pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale.

Outcome measures

Outcome measures
Measure	FLEXUS™ Interspinous Spacer n=62 Participants FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=77 Participants X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the XSTOP® Spacer	No Treatment Not treated with FLEXUS or X-STOP
Mean Visual Analog Scale (VAS) - Left Leg Pain at 24 Months	13.2 millimeters Standard Deviation 27.43	10.7 millimeters Standard Deviation 20.11	—

SECONDARY outcome

Timeframe: 24 months

Population: The short form SF36 was administered to study patients; however, we do not have the proprietary scoring system. Hence the scores could not be calculated.

Change in mental or physical composite score of the short form SF36

Outcome measures

Outcome data not reported

Adverse Events

FLEXUS™ Interspinous Spacer

Serious events: 41 serious events

Other events: 77 other events

Deaths: 5 deaths

X-STOP® Interspinous Spacer

Serious events: 28 serious events

Other events: 72 other events

Deaths: 3 deaths

No Treatment

Serious events: 0 serious events

Other events: 2 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

Director, Clinical Affairs

Globus Medical

Phone: 610-930-1800

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	FLEXUS™ Interspinous Spacer n=107 participants at risk FLEXUS(TM) Interspinous Spacer: Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer	X-STOP® Interspinous Spacer n=106 participants at risk X-STOP® Interspinous Spacer: Treatment of lumbar spinal stenosis with the X-STOP® Spacer	No Treatment n=2 participants at risk Not treated with FLEXUS or X-STOP
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Cancer	1.9% 2/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Cardiac disorders Cardiovascular	7.5% 8/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	4.7% 5/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
General disorders Carpal Tunnel Syndrome	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Vascular disorders Cerebrovascular	1.9% 2/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Nervous system disorders Compressive Peripheral Neuropathy (Non-CTS)	0.00% 0/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.94% 1/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
General disorders Death	4.7% 5/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	2.8% 3/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Gastrointestinal disorders Gastrointestinal	1.9% 2/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.94% 1/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Infections and infestations Infection - Superficial Wound	0.00% 0/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.94% 1/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Musculoskeletal	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.94% 1/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
General disorders Other	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain - Back	0.00% 0/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.94% 1/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain - Hip	2.8% 3/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	2.8% 3/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain - Lower Extremities	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	1.9% 2/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain - Neck and/or Upper Extremities	1.9% 2/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	1.9% 2/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
General disorders Pseudoarthrosis	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Surgical and medical procedures Surgery - Index Level	19.6% 21/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	11.3% 12/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Surgical and medical procedures Surgery - Non-Index Lumbar	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Social circumstances Trauma	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).
Renal and urinary disorders Urogenital	0.93% 1/107 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/106 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).	0.00% 0/2 Adverse events were reviewed and classified by a Clinical Events Committee (CEC).