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Published on: March 23, 2019
Radiographic indices for lumbar developmental spinal stenosis
Jason Pui Yin Cheung1, Karen Ka Man Ng1, Prudence Wing Hang Cheung1
1Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR China.
Background:
Patients with developmental spinal stenosis (DSS) are susceptible to developing symptomatic stenosis due to pre-existing narrowed spinal canals. DSS has been previously defined by MRI via the axial anteroposterior (AP) bony spinal canal diameter. However, MRI is hardly a cost-efficient tool for screening patients. X-rays are superior due to its availability and cost, but currently, there is no definition of DSS based on plain radiographs. Thus, the aim of this study is to develop radiographic indices for diagnosing DSS.
Methods:
This was a prospective cohort of 148 subjects consisting of patients undergoing surgery for lumbar spinal stenosis (patient group) and asymptomatic subjects recruited openly from the general population (control group). Ethics approval was obtained from the local institutional review board. All subjects underwent MRI for diagnosing DSS and radiographs for measuring parameters used for creating the indices. All measurements were performed by two independent investigators, blinded to patient details. Intra- and interobserver reliability analyses were conducted, and only parameters with near perfect intraclass correlation underwent receiver operating characteristic (ROC) analysis to determine the cutoff values for diagnosing DSS using radiographs.
Results:
Imaging parameters from a total of 66 subjects from the patient group and 82 asymptomatic subjects in the control group were used for analysis. ROC analysis suggested sagittal vertebral body width to pedicle width ratio (SBW:PW) as having the strongest sensitivity and specificity for diagnosing DSS. Cutoff indices for SBW:PW were level-specific: L1 (2.0), L2 (2.0), L3 (2.2), L4 (2.2), L5 (2.5), and S1 (2.8).
Conclusions:
This is the first study to define DSS on plain radiographs based on comparisons between a clinically relevant patient group and a control group. Individuals with DSS can be identified by a simple radiograph using a screening tool allowing for better cost-saving means for clinical diagnosis or research purposes.
Insights
New radiographic indices can now identify developmental spinal stenosis (DSS) using simple X-rays. This cost-effective screening tool aids in diagnosing DSS, improving patient care and research accessibility.
Area of Science:
- Radiology
- Orthopedics
- Spinal Surgery
Background:
- Developmental spinal stenosis (DSS) presents a challenge due to pre-existing narrow spinal canals.
- Current MRI-based definitions are not cost-efficient for widespread screening.
- Plain radiographs offer a more accessible and economical alternative for DSS assessment.
Purpose of the Study:
- To develop and validate radiographic indices for diagnosing developmental spinal stenosis (DSS).
- To establish a cost-effective screening tool for DSS using plain radiographs.
Main Methods:
- A prospective cohort study included 148 subjects (DSS patients and asymptomatic controls).
- Both MRI and plain radiographs were utilized for parameter measurement.
- Receiver operating characteristic (ROC) analysis determined cutoff values for diagnosing DSS via radiographs.
Main Results:
- The sagittal vertebral body width to pedicle width ratio (SBW:PW) demonstrated high sensitivity and specificity.
- Level-specific cutoff indices for SBW:PW were established for L1-S1.
- The study successfully defined DSS on plain radiographs.
Conclusions:
- This study provides the first radiographic definition of DSS.
- A simple X-ray-based screening tool can now identify individuals with DSS.
- This approach offers a cost-saving method for clinical diagnosis and research.
