2006 Young Investigator Award Winner: Lumbosacral Nerve Root Displacement and Strain

Gilbert, Kerry K.; Brismée, Jean‐Michel; Collins, Dwayne L.; James, C. Roger; Shah, Rinoo V.; Sawyer, Stanley; Sizer, Phillip S.

doi:10.1097/brs.0b013e318067dd55

Cited by 47 publications

(5 citation statements)

References 20 publications

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“…8 Last, a study using 5 unembalmed cadavers (age range, 72-88 years) found that ankle mobility was limited to between -5° and 5° of dorsiflexion without cutting the calcaneal tendon. 9,10 These findings suggest that the limitations in hip and ankle ranges of motion found in the present study are likely due to age-related changes in this specific sample. Despite the limited range of motion, the maximal increase in strain that was observed in our study (7% at the hip and ankle) is representative of maximal increases in nerve strain when using fresh or unembalmed cadavers.…”

Section: Discussionmentioning

confidence: 45%

Impact of Movement Sequencing on Sciatic and Tibial Nerve Strain and Excursion During the Straight Leg Raise Test in Embalmed Cadavers

Boyd¹,

Topp²,

Coppieters³

2013

Journal of Orthopaedic & Sports Physical Therapy

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Study Design Laboratory study, repeated-measures design. Objectives To quantify differences in sciatic and tibial nerve biomechanics (strain and excursion) during common variations of the straight leg raise (SLR) test. Background Hip flexion and ankle dorsiflexion are the primary movement components of the SLR. It has been suggested that the nervous system is loaded differently when ankle dorsiflexion is added before or after hip flexion. There are, however, no data to either support or refute this suggestion. Methods Strain and excursion in the sciatic and tibial nerve were measured in the hip, knee, and ankle regions during 2 movement sequences for the SLR test in 10 embalmed cadavers. The proximal-to-distal sequence consisted of hip flexion followed by ankle dorsiflexion; the distal-to-proximal sequence consisted of ankle dorsiflexion followed by hip flexion. Results In the SLR end position, strain and excursion were comparable for both sequences for the sciatic and tibial nerve at the knee (P>.24). Strain in the tibial nerve at the ankle was greater with the proximal-to-distal sequence (P = .008), but the actual difference was small (0.8%). The pattern of strain increase and nerve excursion varied between sequences (P≤.009), with nerve strain increasing earlier and being maintained longer in regions closest to the joint that was moved first in the movement sequence. Conclusion Varying the movement sequence does not substantially impact excursion and strain in the end position of the SLR. Therefore, if neurodynamic test sequencing is useful in the differential diagnosis of neuropathies, it is not likely due to differences in strain in the end position of testing. J Orthop Sports Phys Ther 2013;43(6):398–403. Epub 30 April 2013. doi:10.2519/jospt.2013.4413

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Section: Discussionmentioning

confidence: 45%

Impact of Movement Sequencing on Sciatic and Tibial Nerve Strain and Excursion During the Straight Leg Raise Test in Embalmed Cadavers

Boyd¹,

Topp²,

Coppieters³

2013

Journal of Orthopaedic & Sports Physical Therapy

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“…Thus, dissections performed by Smith and Kobayashi may in fact exaggerate movement. Gilbert et al 27 found the L4, L5 and S1 to move on average less than 1 mm during SLR when hip flexion was greater than 60° with intact foraminal ligaments in unembalmed cadavers. Thus, this little motion which can also relate to standing and sitting would likely result in the DRG remaining within the neuroforamen.…”

Section: Discussionmentioning

confidence: 99%

Lumbar Dorsal Root Ganglia Location: An Anatomic and MRI Assessment

et al. 2015

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BackgroundThe dorsal root ganglion (DRG) is a key structure in the mechanism of symptomatic radicular pain, weakness and change in sensation. DRG localization can assist in the decision making process of which areas require decompression, and type of procedure that should be performed to treat radicular symptoms. In this study we determine dimensions of lumbar foramina, DRG and its relationship to the neuroforamina through anatomic and magnetic resonance imaging (MRI) evaluation Agreement between MRI and anatomic assessment of DRG location will be determined.MethodsSixteen embalmed cadavers, 10 females and 6 males, aged 68 to 106 years had an MRI of the thoracolumbar spine followed by dissection. Measurements made included foraminal height and width, DRG size and nerve root take off angle. The center of the DRG and its relationship to the foramina were measured and the probability of agreement between anatomic and MRI assessment were made.ResultsThe greatest width of the DRG was 6.5mm bilaterally at L5 (range 3.2-6.5mm). The nerve root take off angle was largest at L5 on the left (range 50.5o-58.8o) and L4 on the right (range 50.5o-57.2o). The center of the DRG was found bilaterally in the medial zone of the foramen of L1-4 and lateral zone at L5. Foramina size increased from L1 to L5 in the ventral to dorsal and cephalad to caudal direction. Pedicle width increased from L1 to L5. The estimated overall probability of agreement between anatomic and MRI DRG location was 86.3% (95% confidence interval = 77.5% − 92.0%).ConclusionsThe percentage of agreement between MRI and anatomic evaluation of lumbar DRG location significantly exceeded our pre-defined threshold of 70% (p = 0.0013).Clinical RelevanceOur results aid in surgical decision-making as true anatomic position can be directly correlated to what's seen on MRI.

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“…Nerve biomechanics during hip flexion includes increased strain in L4-S1 spinal nerves (Smith et al, 1993), sciatic nerve in the posterior thigh (Babbage et al, 2007, Boyd et al, 2005, Coppieters et al, 2006), and tibial nerve at the knee and ankle (Coppieters et al, 2006). In addition, hip flexion induces measureable distal excursion (means 0.48-2.5 mm) of the L4-S1 spinal nerves (Brieg and Troup, 1979, Smith et al, 1993, Gilbert et al, 2007) and proximal excursion (means 2.4-28.0 mm) of the sciatic nerve in the thigh (Boyd et al, 2005, Coppieters et al, 2006) and tibial nerve at the knee (mean 12.2 mm) and ankle (mean 6.4 mm) (Coppieters et al, 2006). …”

Section: Introductionmentioning

confidence: 99%

The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus

Boyd

Gray

Dilley

et al. 2012

Clinical Biomechanics

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Background The peripheral nervous system has an inherent capability to tolerate the gliding (excursion), stretching (increased strain), and compression associated with limb motions necessary for functional activities. The biomechanical properties during joint movements are well studied but the influence of other factors such as limb pre-positioning, age and the effects of diabetes mellitus are not well established for the lower extremity. The purposes of this pilot study were to compare the impact of two different hip positions on lower extremity nerve biomechanics during an active ankle dorsiflexion motion in healthy individuals and to determine whether nerve biomechanics are altered in older individuals with diabetes mellitus. Methods Ultrasound imaging was used to quantify longitudinal motion of the tibial nerve and transverse plane motion of the tibial and common fibular nerves in the popliteal fossa during active ankle movements. Findings In healthy individuals, ankle dorsiflexion created mean tibial nerve movement of 2.18 millimeters distally, 1.36 millimeters medially and 3.98 millimeters superficially. When the hip was in a flexed position there was a mean three-fold reduction in distal movement. In people with diabetes mellitus there was significantly less distal movement of the tibial nerve in the neutral hip position and less superficial movement of the nerve in both hip positions compared to healthy individuals. Interpretation We have documented reductions in tibial nerve excursion due to limb pre-positioning thought to pre-load the nervous system using a non-invasive methodology. Thus, lower limb pre-positioning impacts nerve biomechanics during ankle motions common in functional activities. Additionally, our findings indicate that nerve biomechanics have the potential to be altered in older individuals with diabetes mellitus compared to younger healthy individuals.

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2006 Young Investigator Award Winner: Lumbosacral Nerve Root Displacement and Strain

Cited by 47 publications

References 20 publications

Impact of Movement Sequencing on Sciatic and Tibial Nerve Strain and Excursion During the Straight Leg Raise Test in Embalmed Cadavers

Impact of Movement Sequencing on Sciatic and Tibial Nerve Strain and Excursion During the Straight Leg Raise Test in Embalmed Cadavers

Lumbar Dorsal Root Ganglia Location: An Anatomic and MRI Assessment

The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus

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