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Research Review By Dr. Michael Haneline©

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Date Posted:

May 2021

Study Title:

Diagnostic tests in the clinical diagnosis of lumbar spinal stenosis: Consensus and Results of an International Delphi Study

Authors:

Tomkins-Lane C, Melloh M & Wong A

Author's Affiliations:

Department of Health and Physical Education, Mount Royal University, Calgary, Canada; Zurich University of Applied Sciences, Switzerland; Hong Kong Polytechnic University, Hong Kong

Publication Information:

European Spine Journal 2020; 29(9): 2188-2197. doi: 10.1007/s00586-020-06481-w.

Background Information:

Lumbar spinal stenosis (LSS) is a degenerative condition that may lead to low back and leg pain, as well as significant functional limitations and disability (1).

The prevalence and economic burden of LSS is increasing globally (and will continue to do so as the population ages), yet there is no gold standard for its diagnosis, which is currently based on a combination of information gathered from the patient’s history, physical examination, imaging, and other diagnostic studies (2, 3).

Given that there were no clinical guidelines regarding the diagnostic criteria for LSS, the authors of this study considered that a consensus-based set of diagnostic criteria for LSS was necessary to refine outcomes assessment and lead to optimized clinical care. To address this gap in clinical care, the International Taskforce on the Diagnosis and Management of Lumbar Spinal Stenosis (Taskforce) was formed at the International Society for the Study of the Lumbar Spine (ISSLS) Annual Meeting in Amsterdam in 2012. The Taskforce was composed of researchers and clinical spine specialists from across the globe including neurosurgeons, orthopedic surgeons, rheumatologists, physiatrists, physical therapists, and chiropractors.

The approach utilized to develop this consensus was the Delphi method, which is a process whereby the results of multiple rounds of questionnaires are sent to a panel of experts (in this case, globally). A phased Delphi process was employed which firstly considered examination of historical items and secondly considered which diagnostic tests were most important when confirming the diagnosis of clinical LSS.

An innovative online survey methodology was utilized to reach the international group of LSS experts. The questionnaires were completed by 279 LSS experts from 29 different countries.

Pertinent Results:

Phase 1:
A Taskforce, comprised of 22 international spine experts, generated a list of 35 diagnostic tests (items) that were used to develop an online survey. This survey was completed by 20 members of the Taskforce, after which the members met in-person to review of the items and select which items should be included in the next round of the Delphi process. Sixteen items were unanimously confirmed by the Members of the Taskforce for inclusion in the online survey.

Phase 2, Round 1:
The 16-item online survey was then distributed to all ISSLS members, with 54 of them completing the survey. The most selected diagnostic tests in this phase were:
  • magnetic resonance imaging (MRI),
  • motor examination,
  • foot pulses,
  • hip examination,
  • reflex examination,
  • x-ray,
  • gait observation, and
  • sensory examination.
Phase 2, Round 2:
After the online survey was completed, 15 Taskforce members met in a focus group meeting to review the results of the survey and to develop a consensus on its contents. As a result, several changes were made to the survey that were designed to focus and streamline the set of diagnostic items. The number of questions was reduced to 10, with all neurological tests being combined into one item and gait observation included as part of the walking test item.

Phase 3:
Invitations to participate in the final survey were sent internationally, with 769 individuals visiting the survey website, 754 providing consent and 562 claiming to be familiar with LSS. Ultimately, 432 individuals (response rate = 56.2%) from 28 different countries completed the survey. 17% were from North and South America, 47% from Europe and Africa, and 32% from Asia, Australia, and New Zealand. The participants’ specialties included orthopedics, physiotherapy, chiropractic, physiatry, primary care, neurosurgery, rheumatology, and geriatrics. Most of the participants were in private practice (33%) or at an academic institution (28%).

The participants certainty of the diagnosis was 60% after selecting the first test, 72% after the second test and 80% after the third. There was no statistically significant change in certainty after 8 items were selected (90.8% certainty).

The most frequently selected tests in this phase included:
  • MRI/CT scan (selected by 88% of respondents),
  • neurological examination (73%),
  • walking test with gait observation (41%),
  • foot pulses and ankle brachial index (ABI)(37%), and
  • hip examination (29%).
The diagnostic test selected most frequently as the first test was neurological examination, followed by MRI/CT scan.

Fourteen of the Taskforce members then met to review the international survey and develop the final consensus.

The following 3 tests were agreed upon as “diagnostic core tests” for confirming the diagnosis of LSS:
  1. Neurological examination (including neural tension sign).
  2. MRI/CT scan.
  3. Walking test with gait observation.
Three additional tests were recommended to rule out other conditions and/or diseases:
  1. Foot pulses/ABI.
  2. Hip examination.
  3. Checking cervical myelopathy.

Clinical Application & Conclusions:

This study expanded on a prior project (4) with similar methodology that resulted in a consensus-based list of historical items/questions that clinicians should use in practice. The following 7 historical questions were deemed most relevant for diagnosing lumbar spinal stenosis:
  1. Does the patient have leg or buttock pain while walking?
  2. Does the patient flex forward to relieve symptoms?
  3. Does the patient feel relief when using a shopping cart or bicycle?
  4. Does the patient have motor or sensory disturbance while walking?
  5. Are the pulses in the foot present and symmetric?
  6. Does the patient have lower extremity weakness?
  7. Does the patient have low back pain?
Spine care practitioners who encounter a patient suspected of having LSS should include these historical questions and then perform the core diagnostic tests:
  1. Neurological examination,
  2. MRI/CT scan, and
  3. a walking test with gait observation.
These tests, when combined with a list of historical items listed above, provide a complete depiction of the clinical diagnosis for LSS. Three additional tests were recommended to rule out other conditions and/or diseases:
  1. Foot pulses/ABI.
  2. Hip examination.
  3. Checking cervical myelopathy.
Practitioners can gain increasing certainty of a correct diagnosis as the historical items and diagnostic tests are applied. After receiving positive responses to the 7 history items and performing the first diagnostic test, one can be roughly 60% certain of the diagnosis of LSS. Certainty increases to 73% after conducting a second test and 80% with a third test. When the full set of historical items and diagnostic tests are combined, certainty in a correct diagnosis increases to 90%.

Study Methods:

A multidisciplinary team of experts developed the initial Delphi items by compiling a list of 35 diagnostic tests that were considered important in the diagnosis of LSS. The list of 35 items was distributed to the taskforce members via an online survey which asked them which items should be included using a yes/no response.

Following the initial online survey, taskforce members met to confirm the list of questions which were to be distributed to ISSLS members via a recursive online survey. The survey was designed such that respondents could indicate the logical order in which they select the diagnostic tests as well as the degree of certainty ascertained by each test when confirming the diagnosis of LSS. Certainty was rated on a visual analog scale that ranged from 0, “not at all certain” to 100, “completely certain.” The same survey approach was used at each stage of the Delphi study. The final survey can be accessed HERE.

After completion of the online survey of ISSLS members, the Taskforce met in-person to participate in a focus group that reviewed the results of the survey to determine whether any changes to the survey items or structure were necessary before conducting an international survey. The final version was distributed to a range of experts who were members of 23 established specialist societies, with the goal of obtaining 200 responses. Data were included in the analysis only from respondents who self-reported as being familiar with the diagnosis and treatment of LSS.

After compilation of the results from the survey of experts, the Taskforce met in another focus group to discuss the results of the international survey and to confirm the final set of recommended diagnostic tests.

Study Strengths / Weaknesses

This was a well-done Delphi study that was able to develop an international consensus on which diagnostic tests are the most important in confirming the clinical diagnosis of LSS. The authors considered that the consensus on diagnostic tests, which incorporated input from 432 multidisciplinary spine experts from around the world, was strong enough, when combined with the set of historical items they developed, to form the basis for a common language and approach in both LSS research and clinical care.

While input was collected anonymously from more than 400 spine experts from around the world, there were some limitations, including:
  • The sample of respondents came from willing members of the 23 participating societies that were ask to distribute the survey, so it is possible that these results may not truly represent the opinions of all spinal experts globally.
  • The results of this study represent a consensus of spinal experts; however, the diagnostic accuracy of these tests remains to be validated.

Additional References:

  1. Deyo RA. Treatment of lumbar spinal stenosis: a balancing act. Spine J 2010; 10: 625–27.
  2. Haskins R, Osmotherly PG, Rivett DA. Diagnostic clinical prediction rules for specific subtypes of low back pain: a systematic review. J Orthop Sports Phys Ther 2015; 45: 61–76.
  3. Genevay S, Atlas SJ. Lumbar spinal stenosis. Best Pract Res Clin Rheumatol 2010; 24: 253–265.
  4. Tomkins-Lane C, Melloh M, Lurie J et al. ISSLS Prize Winner: consensus on the clinical diagnosis of lumbar spinal stenosis: results of an International Delphi Study. Spine 2016; 41:1239-46.

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