Kerry K. Gilbert

2006 Young Investigator Award Winner: lumbosacral nerve root displacement and strain: part 2. A comparison of 2 straight leg raise conditions in unembalmed cadavers.

Study Design. An inferential cadaveric study. Objectives. To compare the displacement and strain of the lumbosacral nerve roots during different conditions of straight leg raise (SLR) with intact foraminal ligaments. Summary of Background Data. Clinicians use sensitizing movements such as dorsiflexion during neurodynamic testing, assuming that these prepositions influence the displacement or strain to the lumbosacral nerve roots. Little is known about the effect of these prepositions on neurodynamic behavior. Methods. Lower limbs and associated nerve roots of 5 unembalmed cadavers (n = 10) were used to evaluate the displacement and strain of the L4, L5, and S1 roots during 2 different SLR conditions. Fluoroscopic images of intraneural metal markers were digitized to evaluate displacement and strain during SLR with no preposition (SLR NPP) of the ankle and SLR with dorsiflexion preposition (SLR DF) of the ankle, respectively. Results. SLR NPP produced larger distal displacement at L5 and S1, (P < 0.001) when compared with SLR DF. Displacement comparisons at L4 were nonsignificant (P = 0.051). While nonsignificant, medium to large effect sizes (0.60–0.96) suggest that SLR DF may produce more strain than the SLR NPP condition. Conclusions. Prepositions of the SLR test alter the displacement and possibly the strain of the lumbosacral nerve roots in the lateral recess.

2006 young investigator award winner : Lumbosacral nerve root displacement and strain Part 1. A novel measurement technique during straight leg raise in unembalmed cadavers

Study Design. A descriptive cadaveric study incorporating a novel nerve root marking technique. Objectives. To describe the displacement and strain of the lumbosacral nerve roots in the lateral recess during straight leg raise (SLR) without disrupting the foraminal ligaments. Summary of Background Data. Previous studies document 2 to 8 mm of lumbosacral nerve root displacement during SLR. Prior dissection methods incorporated laminectomy and facetectomy. Methods. Lower limbs and associated nerve roots of 5 unembalmed cadavers (n = 10) were studied. Metal markers were inserted intraneurally within the lateral recess of L4, L5, and S1 with a modified spinal needle. Fluoroscopic images were digitized to evaluate displacement and strain during SLR. Results. The lumbosacral nerve roots in the lateral recess moved less and experienced less strain during SLR than described in previously published reports. Statistically significant distal displacement occurred at hip positions greater than 60° of flexion at all nerve root levels (P < 0.01). Conclusions. The lumbosacral nerve roots (L4, L5, S1) moved less and underwent less strain during SLR testing than previously reported and may require hip motion greater than 60° to produce substantive displacement in the lateral recess. Additional research is needed to examine the effects of prepositioning during SLR.

The effects of neurodynamic mobilization on fluid dispersion within the tibial nerve at the ankle: an unembalmed cadaveric study

Abstract Objective: To evaluate the effects of neurodynamic mobilization on the fluid dynamics of the tibial nerve in cadavers. Background: Evidence showing patients benefit from neural mobilization is limited. Mechanisms responsible for changes in patient symptoms are unclear. Methods: Bilateral lower limbs of six unembalmed cadavers (n = 12) were randomized into matched pairs and dissected to expose the tibial nerve proximal to the ankle. Dye composed of Toulidine blue and plasma was injected into the nerve. The longitudinal dye spread was measured pre‐ and post‐mobilization. The experimental group received the intervention consisting of 30 repetitions of passive ankle range of motion over the course of 1 minute. The matched control limb received no mobilization. Data were analysed using a 2×2 repeated measures ANOVA with subsequent t‐tests for pairwise comparisons. Results: Mean dye spread was 23·8±10·2 mm, a change of 5·4±4·7% in the experimental limb as compared to 20·7±6·0 mm, a change of −1·5±3·9% in the control limb. The ANOVA was significant (P⩽0·02) for interaction between group (experimental/control) and time (pre‐mobilization/post‐mobilization). t‐test results were significant between pre‐ and post‐mobilization of the experimental leg (P = 0·01), and between control and experimental limbs post‐mobilization (P⩽0·02). Conclusion: Passive neural mobilization induces dispersion of intraneural fluid. This may be clinically significant in the presence of intraneural edema found in pathological nerves such as those found in compression syndromes.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 1: A Minimally Invasive Assessment in Unembalmed Cadavers.

Study Design. A cross-sectional cadaveric examination of displacement and strain measured at the level of the cervical nerve roots during upper limb neural tension testing (ULNTT) with median nerve bias. Objective. To determine the displacement and strain of cervical nerve roots C5–C8 during ULNTT with minimal disruption of surrounding tissues. Summary of Background Data. Clinical examination of neural pathology involving cervical nerve roots is difficult because of the transient nature of pathologies, such as cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Cadaveric studies have demonstrated significant displacement and strain in lumbosacral nerve roots during neurodynamic testing of the lower extremity. Examination into the biomechanical behaviors of cervical nerve roots during ULNTT has not been performed. Methods. Eleven unembalmed cadavers were positioned supine as though undergoing ULNTT. Radiolucent markers were implanted into cervical nerve roots C5–C8. Posteroanterior fluoroscopic images were captured at resting and ULNTT positioning. Images were digitized and displacement and strain were calculated. Results. ULNTT resulted in significant inferolateral displacement (average, 2.16 mm–4.32 mm, P < 0.001) of cervical nerve roots C5–C8. There was a significant difference in inferolateral displacement between the C5 and C6 nerve roots (3.15 mm vs. 4.32 mm, P = 0.009). ULNTT resulted in significant strain (average, 6.80%–11.87%, P < 0.001) of cervical nerve roots C5–C8. There was a significant difference in strain between the C5 and C6 nerve roots (6.60% vs. 11.87%, P = 0.03). Conclusion. ULNTT caused significant inferolateral displacement and strain in cervical nerve roots C5–C8. These results provide the mechanical foundation for the use of ULNTT in clinical evaluation of pathology in the cervical region, such as in cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Level of Evidence: 2

Rate of False Positive Using the Cyriax Release Test for Thoracic Outlet Syndrome in an Asymptomatic Population

Abstract The purpose of this study was to determine the rate of false positive findings during the Cyriax Release Test for Thoracic Outlet Syndrome (TOS) in an asymptomatic population. The 119 subjects (238 shoulder girdles) with a mean age of 36.3 years included in the study were asked to report any symptoms noted at 1, 3, 5, 10 and 15 minutes of holding the Cyriax Release Test position, which consisted of passive shoulder girdle elevation. Specificity was calculated for each time interval and was highest at 1 minute (97.4%), with a progressive decrease to 77.4% at 15 minutes. Correlation and chi-square analyses were run between demographic data/medical history and positive test results. Neck pain was the only statistically significant variable (p < 0.001). The high specificity of the Cyriax Release Test at 1 and 3 minutes justifies its continued use in clinical setting for the diagnosis of Thoracic Outlet Syndrome.

Diagnosis and management of the painful shoulder. Part 2: examination, interpretation, and management.

Abstract: Diagnosis, interpretation and subsequent management of shoulder pathology can be challenging to clinicians. Because of its proximal location in the schlerotome and the extensive convergence of afferent signals from this region to the dorsal horn of the spinal cord, pain reference patterns can be broadly distributed to the deltoid, trapezius, and or the posterior scapular regions. This pain behavior can make diagnosis difficult in the shoulder region, as the location of symptoms may or may not correspond to the proximity of the pain generator. Therefore, a thorough history and reliable physical examination should rest at the center of the diagnostic process. Effective management of the painful shoulder is closely linked to a tissue‐specific clinical examination. Painful shoulder conditions can present with or without limitations in passive and or active motion. Limits in passive motion can be classified as either capsular or noncapsular patterns. Conversely, patients can present with shoulder pain that demonstrates no limitation of motion. Bursitis, tendopathy and rotator cuff tears can produce shoulder pain that is challenging to diagnose, especially when they are the consequence of impingement and or instability. Numerous nonsurgical measures can be implemented in treating the painful shoulder, reserving surgical interventions for those patients who are resistant to conservative care.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 2: Role of Foraminal Ligaments in the Cervical Spine.

Study Design. A cross-sectional cadaveric examination of the mechanical effect of foraminal ligaments on cervical nerve root displacement and strain. Objective. To determine the role of foraminal ligaments by examining differences in cervical nerve root displacement and strain during upper limb neural tension testing (ULNTT) before and after selective cutting of foraminal ligaments. Summary of Background Data. Although investigators have determined that lumbar spine foraminal ligaments limit displacement and strain of lumbosacral nerve roots, similar studies have not been conducted to prove that it is true for the cervical region. Because the size, shape, and orientation of cervical spine foraminal ligaments are similar to those in the lumbar spine, it is hypothesized that foraminal ligaments in the cervical spine will function in a similar fashion. Methods. Radiolucent markers were implanted into cervical nerve roots C5–C8 of 9 unembalmed cadavers. Posteroanterior fluoroscopic images were captured at resting and upper limb neural tension testing positioning before and after selective cutting of foraminal ligaments. Results. Selective cutting of foraminal ligaments resulted in significant increases in inferolateral displacement (average, 2.94 mm [ligaments intact]–3.87 mm [ligaments cut], P < 0.05) and strain (average, 9.33% [ligaments intact]–16.31% [ligaments cut], P < 0.03) of cervical nerve roots C5–C8 during upper limb neural tension testing. Conclusion. Foraminal ligaments in the cervical spine limited cervical nerve root displacement and strain during upper limb neural tension testing. Foraminal ligaments seem to have a protective role, reducing displacement and strain to cervical nerve roots during tension events. Level of Evidence: 2

Effects of lower limb neurodynamic mobilization on intraneural fluid dispersion of the fourth lumbar nerve root: an unembalmed cadaveric investigation

Objectives: Manual and physical therapists incorporate neurodynamic mobilisation (NDM) to improve function and decrease pain. Little is known about the mechanisms by which these interventions affect neural tissue. The objective of this research was to assess the effects of repetitive straight leg raise (SLR) NDM on the fluid dynamics within the fourth lumbar nerve root in unembalmed cadavers. Methods: A biomimetic solution (Toluidine Blue Stock 1% and Plasma) was injected intraneurally, deep to the epineurium, into the L4 nerve roots of seven unembalmed cadavers. The initial dye spread was allowed to stabilise and measured with a digital calliper. Once the initial longitudinal dye spread stabilised, an intervention strategy (repetitive SLR) was applied incorporating NDMs (stretch/relax cycles) at a rate of 30 repetitions per minute for 5 minutes. Post-intervention calliper measurements of the longitudinal dye spread were measured. Results: The mean experimental posttest longitudinal dye spread measurement (1.1 ± 0.9 mm) was significantly greater (P = 0.02) than the initial stabilised pretest longitudinal dye spread measurement. Increases ranged from 0.0 to 2.6 mm and represented an average of 7.9% and up to an 18.1% increase in longitudinal dye spread. Discussion: Passive NDM in the form of repetitive SLR induced a significant increase in longitudinal fluid dispersion in the L4 nerve root of human cadaveric specimen. Lower limb NDM may be beneficial in promoting nerve function by limiting or altering intraneural fluid accumulation within the nerve root, thus preventing the adverse effects of intraneural oedema.

Effects of simulated neural mobilization on fluid movement in cadaveric peripheral nerve sections: implications for the treatment of neuropathic pain and dysfunction

Abstract Background and purpose: Neural mobilization techniques are used clinically to treat neuropathic pain and dysfunction. While selected studies report efficacy of these techniques, the mechanisms of benefit are speculative. The purpose of this study was to evaluate the effects of in vitro simulated stretch/relax neural mobilization cycles on fluid dispersion within sections of unembalmed cadaveric peripheral nerve tissue. Methods: Bilateral sciatic nerve sections were harvested from six cadavers. Matched pairs of nerve sections were secured in a tissue tester and injected with a plasma/Toluidine Blue dye solution. Once the initial dye spread stabilized, the experimental nerve sections underwent 25 stretch/relaxation cycles (e.g. simulated neural mobilization) produced by a mechanical tissue tester. Post-test dye spread measurements were compared to pre-test measurements as well as control findings (no simulated mobilization). Data were analyzed using paired t-tests. Results: Individual dye spread measurements were reliable [ICC(3,1) = 0·99]. The post-test intraneural fluid movement (dye spread) in the experimental section increased significantly with simulated neural mobilization compared to pre-test measurements (3·2±2·1 mm; P = 0·015) and control measurements (3·3±2·7 mm; P = 0·013). Conclusion: Repetitive simulated neural mobilization, incorporating stretch/relax cycles, of excised cadaveric peripheral nerve tissue produced an increase in intraneural fluid dispersion. Neural mobilization may alter nerve tissue environment, promoting improved function and nerve health, by dispersing tissue fluid and diminishing intraneural swelling and/or pressure.

Diagnosis and Management of the Painful Shoulder. Part 1: Clinical Anatomy and Pathomechanics

Abstract: Distinctive anatomical features can be witnessed in the shoulder complex, affording specific pathological conditions. Disorders of the shoulder complex are multifactoral and features in both the clinical anatomy and biomechanics contribute to the development of shoulder pain. The sternocalvicular, acromioclavicular, glenohumeral, and scapulothoracic joints must all participate in function of the shoulder complex, as each biomechanically contributes to functional movements and clinical disorders witnessed in the shoulder region. A clinicians ability to effectively evaluate, diagnose, and treat the shoulder is largely reliant upon a foundational understanding of the clinical anatomy and biomechanics of the shoulder complex. Thus, clinicians are encouraged to consider these distinctions when examining and diagnosing disorders of the shoulder.