A consensus approach toward the standardization of spinal stiffness measurement using a loaded rolling wheel device: results of a Delphi study

Abstract

Background Spinal stiffness assessment has the potential to become an important clinical measure. Various spinal stiffness-testing devices are available to help researchers objectively evaluate the spine and patient complaints. One of these is VerteTrack, a device capable of measuring posteroanterior displacement values over an entire spinal region. This study aimed to develop a best-practice protocol for evaluating spinal stiffness in human participants using VerteTrack. Methods Twenty-five individuals with research experience in measuring spinal stiffness, or who were trained in spinal stiffness measurement using the VerteTrack device, were invited to participate in this 3-Round Delphi study. Answers to open-ended questions in Round 1 were thematically analyzed and translated into statements about VerteTrack operation for spinal stiffness measurements. Participants then rated their level of agreement with these statements using a 5-point Likert scale in Rounds 2 and 3. A descriptive statistical analysis was performed. Consensus was achieved when at least 70% of the participants either strongly agreed, agreed, (or strongly disagreed, disagreed) to include a statement in the final protocol. Results Twenty participants completed Round 1 (80%). All these participants completed Rounds 2 and 3. In total, the pre-defined consensus threshold was reached for 67.2% (123/183) of statements after three rounds of surveys. From this, a best-practice protocol was created. Conclusions Using a Delphi approach, a consensus-based protocol for measuring spinal stiffness using the VerteTrack was developed. This standard protocol will help to improve the accuracy, efficiency, and safety of spinal stiffness measurements, facilitate the training of new operators, increase consistency of these measurements in multicenter studies, and provide the synergy and potential for data comparison between spine studies internationally. Although specific to VerteTrack, the resulting standard protocol could be modified for use with other devices designed to collect spinal stiffness measures.

Static palpation ain’t easy: Evaluating palpation precision using a topographical map of the lumbar spine as a reference

“…We used three raters to conduct the translational process to reduce bias in this approach. Although there may be other ways to complete this spatial synchronization of stiffness data, we have confidence in our approach [ 17 ]. Any mistranslations should not have resulted in more than minor changes.…”

“…The result was a topographical mapping of the lumbar lordosis. The digitization was completed by one of two research assistants who carefully located the center of the location previously marked by the clinician with a device that measures spinal stiffness [ 17 ]). Before each assessment, the participants were provided with clear introductions on remaining still and holding their breath during testing.…”

“…The position of these markings was then digitized in threedimensional space and served as reference points for the original study [21]. The same digitizing equipment was then used to continuously collect three-dimensional position data of a wheel that rolled along the back's surface through a trajectory that connected the previously digitized locations of the spinous processes [17,[23][24][25].…”

“…In this study, we used a new approach that employed the topography of the lumbar spine as the standard by which experienced clinicians identified locations of spinous processes. Along that topography, palpation could be assessed for their precision [17]. This approach distinguishes itself from designs typically used in previous validation studies, which have been dedicated palpation studies that investigated the precision of static palpation without a reference [9][10][11] or with an ultrasonic reference [14,16,[18][19][20], which is not without challenges.…”

Neurological update: consult the neurosurgical oracle for a standard operating procedure

“…There are some points of discussion on the methods we have applied: first, how does one define consensus? In our approach, we choose ≥ 80%, but this is arbitrary [ 16 , 17 , 23 , 24 ]. Ideally, one may perform a sensitivity analysis investigating the influence of the consensus threshold on medical decisions.…”