Trial Outcomes & Findings for Sagittal Plane Shear Index for Planning Lumbar Stenosis Surgery (NCT NCT03754972)

Last Updated: 2025-05-29

Results Overview

The surgeons will record their surgical plan (decompression alone or decompression plus fusion) prior to receiving the SPSI report. The surgeon will then integrate the data in the SPSI report into their surgical planning and record a post-SPSI report surgical plan. The proportion of lumbar spinal stenosis surgery plans that change after an objective metric for spinal stability is included in the surgical planning will be determined. If the proportion of plans that change after integration of the SPSI report is greater than expected due to subjectivity in surgical planning, then the SPSI report will be considered clinically effective and further research will be pursued.

Recruitment status

COMPLETED

Study phase

Target enrollment

100 participants

Primary outcome timeframe

Pre-surgery

Results posted on

2025-05-29

Participant Flow

Patients from four tertiary non-academic hospitals in The Netherlands were recruited by employing a non-probability purposive sampling method.

Participant milestones

Participant milestones
Measure	Lumbar Spinal Stenosis Surgery Candidate Patients with lumbar spinal stenosis and spondylolisthesis that have previously consented to surgical treatment. After recording the initial surgical plan, the Sagittal plane shear index (SPSI) will be provided to the surgeon. The surgeon may change the initial surgical plan based on the stability metric. Sagittal plane shear index (SPSI): Report SPSI to surgeon after surgeon records an initial surgical plan, and determine whether the objective spinal stability metric influences a change in the surgical plan.
Overall Study STARTED	100
Overall Study COMPLETED	75
Overall Study NOT COMPLETED	25

Reasons for withdrawal

Reasons for withdrawal
Measure	Lumbar Spinal Stenosis Surgery Candidate Patients with lumbar spinal stenosis and spondylolisthesis that have previously consented to surgical treatment. After recording the initial surgical plan, the Sagittal plane shear index (SPSI) will be provided to the surgeon. The surgeon may change the initial surgical plan based on the stability metric. Sagittal plane shear index (SPSI): Report SPSI to surgeon after surgeon records an initial surgical plan, and determine whether the objective spinal stability metric influences a change in the surgical plan.
Overall Study Protocol Violation	25

Baseline Characteristics

Sagittal Plane Shear Index for Planning Lumbar Stenosis Surgery

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Lumbar Spinal Stenosis Surgery Candidate n=100 Participants Patients were eligible for participation if they had i) symptoms consistent with single-level LSS, ii) central and/or foraminal stenosis between two adjacent vertebrae confirmed by MRI, iii) grades 1 (10 to 25%) or 2 (26 to 50%) anterior or retro-spondylolisthesis according to the Meyerding classification,28 iv) no history of prior lumbar spinal surgery and v) were suitable for Posterior Lumbar Interbody Fusion (PLIF) surgery using posterior pedicle screws, rods and/or a spinal cage in case instrumented fusion was considered. Patients were excluded if they had i) stenosis at the level of a transitional vertebra or severe stenosis that required a wide decompression that was judged to destabilize the spine, ii) lateral spondylolisthesis, iii) scoliosis involving a lumbar curve \> 10 degrees, iv) an American Society of Anesthesiologists (ASA) class IV or higher disease or v) were pregnant.
Age, Continuous	66.05 years STANDARD_DEVIATION 10.21 • n=5 Participants
Sex: Female, Male Female	64 Participants n=5 Participants
Sex: Female, Male Male	36 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	100 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	5 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	4 Participants n=5 Participants
Race (NIH/OMB) White	91 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Region of Enrollment Netherlands	100 participants n=5 Participants
ODI	39.6 units on a scale STANDARD_DEVIATION 16.6 • n=5 Participants

PRIMARY outcome

Timeframe: Pre-surgery

Population: Patients meeting all inclusion criteria, not meeting any exclusion criteria, and where intervertebral rotation at the treatment level was \>= 5 degrees between flexion and extension

Outcome measures

Outcome measures
Measure	Lumbar Spinal Stenosis Surgery Candidate n=75 Participants Patients with lumbar spinal stenosis and spondylolisthesis that have previously consented to surgical treatment. After recording the initial surgical plan, the Sagittal plane shear index (SPSI) will be provided to the surgeon. The surgeon may change the initial surgical plan based on the stability metric. Sagittal plane shear index (SPSI): Report SPSI to surgeon after surgeon records an initial surgical plan, and determine whether the objective spinal stability metric influences a change in the surgical plan.
Proportion of Surgical Plans Recorded Prior to the SPSI Report That Are Altered After Integration of SPSI Into the Surgical Planning SPSI supported surgeons initial surgical plan	47 Surgical plans
Proportion of Surgical Plans Recorded Prior to the SPSI Report That Are Altered After Integration of SPSI Into the Surgical Planning Surgical plan changed after using SPSI in planning	22 Surgical plans
Proportion of Surgical Plans Recorded Prior to the SPSI Report That Are Altered After Integration of SPSI Into the Surgical Planning Surgeons chose not to implament a change in surgical plan supported by the SPSI metric	6 Surgical plans

SECONDARY outcome

Timeframe: Pre-surgery

Prior research has reported that SPSI is significantly higher at lumbar levels where a facet fluid sign is observed in a MRI exam. Outcome 2 is intended to test the hypothesis that this prior finding can be repeated. SPSI will be calculated for all levels in the lumbar spine from preoperative lumbar flexion-extension radiographs. The surgeons will record whether they observe the fluid sign in the facet joints based on review of a preoperative MRI exam. Statistical tests will be performed for an association between preoperative SPSI and the presence or absence of a facet fluid sign observed by the treating surgeon in a preoperative MRI exam of the lumbar spine.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: One year after surgery

Prior research has documented that decompression surgery may compromise the stability of the treated level. To test whether this phenomena can be documented using the SPSI metric, SPSI measured at 12 months will be compared to SPSI measured preoperatively. This will be assessed only in patients treated with decompression alone (patients treated with fusion in addition to decompression will not be included). Statistical tests will be used to determine the proportion of levels treated using decompression only where the SPSI at 12 months was at least 1 standard deviation greater than preoperatively.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: 12 and 24 months

Multiple prior studies have documented reoperation rates following surgery for lumbar spinal stenosis. To test whether the reoperation rate in the current study is comparable to prior studies, clinical records will be reviewed to determine whether additional surgery was performed at the treated and/or adjacent levels. Statistical tests will be used to compare the reoperation rates at 12 and 24 months after the index surgery to reoperation rates previously reported in the peer-reviewed literature.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: 12 months

The existing peer-reviewed literature is inconsistent with respect to the hypothesis that the Oswestry Disability Index (ODI) is affected by a non-union of a lumbar level treated using fusion surgery. The ODI quantifies disability related to low back pain. The ODI is measured on a scale of 0 to 100, with higher scores indicating greater disability. The ODI will be recorded preoperatively and at 12 months following surgery. Each lumbar level will be classified as fused if intervertebral rotation between flexion and extension is \< 2 degrees and there is an absence of a discontinuity in bone bridging between vertebrae. The ODI at 12 months, as well as the change in ODI relative to preoperative outcomes will be compared for subjects classified as fused versus not-fused. This test will only be performed for subjects where the stenotic lumbar level was treated using decompression and fusion.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: 12 months

The existing peer-reviewed literature is inconsistent with respect to the hypothesis that leg pain assessed using a Numerical Rating Scale (NRS) is affected by a non-union of a lumbar level treated using fusion surgery. Leg pain is measured on a scale of 1 to 10, with higher scores indicating worse leg pain. Leg pain will be recorded preoperatively and at 12 months following surgery. Each lumbar level will be classified as fused if intervertebral rotation between flexion and extension is \< 2 degrees and there is an absence of a discontinuity in bone bridging between vertebrae. The leg pain NRS data at 12 months, as well as the change in leg pain relative to preoperative outcomes will be compared for subjects classified as fused versus not-fused. This test will only be performed for subjects where the stenotic lumbar level was treated using decompression and fusion.

Outcome measures

Outcome data not reported

Adverse Events

Per Protocol

Serious events: 26 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Per Protocol n=75 participants at risk Subject met all inclusion criteria, did not have any exclusion criteria, and had \>= 5 deg intervertebrakl rotation at the treatment level at PreOp.
Musculoskeletal and connective tissue disorders Recurrent leg pain after decompression surgery	1.3% 1/75 • 2 years
Musculoskeletal and connective tissue disorders Patient requested two level fusion after 1 level decompression	1.3% 1/75 • 2 years
Musculoskeletal and connective tissue disorders Not related to use of SPSI for surgical planning	22.7% 17/75 • 2 years
General disorders Not related to use of SPSI for surgical planning	9.3% 7/75 • 2 years

Other adverse events

Adverse event data not reported

Additional Information

Trevor Grieco

Medical Metrics, Inc

Phone: 713-850-7500

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place