Diagnostic accuracy of the upper limb neurodynamic test 1 using neurodynamic sequencing in diagnosis of carpal tunnel syndrome.

BACKGROUND: The upper limb neurodynamic test 1 is used in the diagnosis of median nerve neuropathies such as carpal tunnel syndrome but its diagnostic validity remains limited. Neurodynamic sequencing has been suggested to increase the specificity of the neurodynamic tests, however, to date, information on the diagnostic accuracy of this variation in neurodynamic testing is required. OBJECTIVES: The aim of this study was to analyze the diagnostic validity of the local sequence of ULNT1 (LS-ULNT1) (i.e. a sequence that begins at the joint where the problem is (wrist) and progressively moves joints further away from it), in the diagnosis of CTS. A secondary aim was to describe the location of sensory responses to this modified neurodynamic test sequence. DESIGN: A prospective diagnostic accuracy study was designed. METHOD: Nerve conduction studies were used as the gold standard. The LS-ULNT1 was performed in 58 consecutive patients (17 men, 44 women) with suspected CTS. RESULTS: Sensitivity of the LS-ULNT1 was 65.7% (CI 48.0-80.9%) and the specificity was 95.7% (CI 78.1-99.9%). The positive and negative likelihood ratios were >5 and < 0.5, respectively, indicating the ability of the test to generate small but sometimes important changes in post-test probability. CONCLUSIONS: The overall results of this study showed that the LS-ULNT1 could be useful in confirming the diagnosis of CTS. The test demonstrated high specificity and the +LR indicated the ability of the test to generate changes in posttest probability, especially with a positive LS-ULNT1 result.

Treatment of Sciatica and Lumbar Radiculopathy with an Intervertebral Foramen Opening Protocol: Pilot Study in a Hospital Emergency and In-patient Setting.

AIMS: Perform a pilot study of a static nerve root foramen opening protocol for lumbar radiculopathy from disc hernia in an emergency hospital setting to establish if patients could execute the protocol, consistency would occur across outcomes, superior outcomes would occur in the experimental group, and if the protocol would be safe. METHODS: Patients with sciatica arrived of their own volition at the local emergency hospital department, were admitted for care and were randomized into two groups: 1) control (n = 10): forward bending, walking, and medication; and 2) experimental (n = 10) as control subjects, plus a static lumbar foramen opening protocol using flexion and contralateral lateral flexion (side-lying). Outcomes were back and leg pain (i.e. visual analog scale), disability (i.e. EuroQol5D5L and Oswestry) and straight leg raise. RESULTS: At admission, the baseline outcome variables between groups were not significantly different. All patients had moderate or large disc hernias on MRI and 75% had neurological deficits in electrophysiology. At discharge, patients in the experimental group were significantly better (p ≤ .05) than controls in all outcomes. Statistical analysis of the outcomes produced greater significance, effect sizes and minimal clinically important differences in the experimental group. Patients in the experimental group consumed less medication than control patients (21% versus 79%), including less than half the opioids (tramadol). No adverse responses occurred. CONCLUSIONS: Patients could perform the protocol and superior outcomes occurred, with no adverse effects. The data support more detailed study of therapeutic efficacy, days in hospital, costs, conversion to surgery, and medication consumption, including opioids.

Differential movement of the median nerve and biceps brachii at the elbow in human cadavers.

BACKGROUND: It is important to establish if mechanical testing for physical problems in the human is specific or non-specific for structures - e.g. muscle and nerve. The median nerve at the wrist can be moved in preference to its adjacent flexor digitorum longus muscle, but it is necessary to know if this specificity extends to the elbow. We therefore measured mechanical behaviour of the median nerve at the elbow compared to its adjacent muscle - biceps brachii. METHODS: This cross-sectional study on nine fresh frozen cadaver upper limbs used differential variable reluctance transducers and Vernier callipers to measure strain and excursion in the median nerve and biceps brachii during cervical contralateral lateral flexion in glenohumeral abduction: 0°, 30°, 60° and 90°. FINDINGS: Proximal excursion and strain with contralateral lateral flexion occurred in the median nerve primarily at 60° and 90° abduction (p < 0.05), but no changes occurred in the muscle (p > 0.05). INTERPRETATION: This study provides evidence of emphasising load to peripheral nerve over biceps at the elbow during cervical contralateral lateral flexion.

Extending the straight leg raise test for improved clinical evaluation of sciatica: validity and diagnostic performance with reference to the magnetic resonance imaging.

BACKGROUND: The straight leg raise test (SLR) is one of the most utilized and studied physical tests in patients with low back pain (LBP) for the detection of lumbar disc herniation (LDH), showing high sensitivity and heterogeneous or low specificity. The high incidence of asymptomatic 'pathologic' findings in the magnetic resonance imaging (MRI) scans may cause verification bias to these results. We studied an extended SLR (ESLR) by adding location-specific structural differentiation movements (hip internal rotation or ankle dorsiflexion) to the traditional SLR for it to better differentiate neural symptoms from musculoskeletal. Previously, the ESLR has shown almost perfect interrater reliability between examiners and ability to detect sciatic patients. In this study, we investigated whether a 'positive' ESLR finding is associated with pathology seen on MRI. METHODS: Forty subjects comprised the study population, 20 in sciatic group and 20 in control group. The ESLR was performed 'blinded' to the subjects. After the ESLR, each subject's lumbar MRI was evaluated. The MRIs were analyzed independently by 2 senior radiologists and a spine specialist clinician. The ESLR and MRI results were cross-tabulated. To obtain the odds ratio (OR) with positive ESLR or SLR results for LDH or nerve root compression (NC), a binary logistic regression analysis with subjects' age, gender, height and weight was performed. ESLR's validity was assessed by combination of interrater agreement and percentage prevalence of both LDH and NC. RESULTS: Of sciatic (ESLR+) patients, 85 % had LDH and 75 % NC in the MRI. Not surprisingly, MRI showed a very high incidence of 'false-positive' findings with the ESLR negative group. The ESLR showed 0.85 sensitivity and 0.45 specificity for LDH and 0.75 sensitivity and 0.50 specificity for NC. A positive result in the ESLR was found to be strongly associated with for both LDH and NC: the OR was 8.0 (p = 0.028) and 5.6 (p = 0.041), respectively. CONCLUSIONS: The ESLR shows high validity in detecting neural symptoms and is strongly associated with pathology seen in the MRI when judged positive. We suggest the use of ESLR in clinical practice as a part of clinical examination, where it may prove to be a valuable tool in detecting patients with sciatic symptoms.

Extending the straight leg raise test for improved clinical evaluation of sciatica: reliability of hip internal rotation or ankle dorsiflexion.

BACKGROUND: The straight leg raise (SLR) is the most commonly applied physical tests on patients with sciatica, but the sensitivity and specificity ratings for disc hernia and neural compression leave areas for improvement. Hip internal rotation tensions the lumbosacral nerve roots and ankle dorsiflexion tensions the sciatic nerve along its course. We added these movements to the SLR (extended SLR = ESLR) as structural differentiators and tested inter-rater reliability in patients with LBP, with and without sciatica. METHODS: Forty subjects were recruited to the study by the study controller (SC), 20 in the sciatic group and in the control group. Two independent examiners (E1&E2) performed the ESLR and did not communicate to the subjects other than needed to determine the outcome of the ESLR. First, SLR was performed traditionally until first responses were evoked. At this hip flexion angle, a location-specific structural differentiation was performed to confirm whether the emerged responses were of neural origin. Cohen's Kappa score (CK) for interrater reliability was calculated for ESLR result in detection of sciatic patients. Also, the examiners' ESLR results were compared to the traditional SLR results. RESULTS: The interrater agreement between Examiner 1 and Examiner 2 for the ESLR was 0.85 (p < 0.001, 95%CI: 0.71-0.99) translating to almost perfect agreement as measured by Cohen's Kappa When the ESLR was compared to the traditional SLR, the overall agreement rate was 75% (30/40). Kappa values between the traditional SLR and the E1's or E2's ESLR results were 0.50 (p < 0.0001; 95%CI 0.27-0.73) and 0.54 (p < 0.0001; 95%CI 0.30-0.77), respectively. CONCLUSIONS: ESLR with the addition of location-specific structural differentiation is a reliable and repeatable tool in discerning neural symptoms from musculoskeletal in patients with radiating low back pain. We recommend adding these movements to the standard SLR with aim of improving diagnostic ability.

Effect of cervical contralateral lateral flexion on displacement and strain in the median nerve and flexor digitorum superficialis at the wrist during the ULNT1 - Cadaveric study.

INTRODUCTION: A key issue in neurodynamic testing is whether a manoeuvre designed to produce differential biomechanical behaviour (structural differentiation) of nerve compared to adjacent muscle is mechanically accurate. The aim of this study was to investigate the capacity of cervical contralateral lateral flexion to produce differential biomechanical behaviour of the median nerve at the wrist (mechanical specificity) in relation to the adjacent muscle (flexor digitorum superficialis) at different ranges of upper limb neurodynamic test 1 in cadavers. MATERIAL AND METHODS: A cross-sectional study was carried out. In fresh frozen cadavers, with microstrain devices and Vernier calipers, strain and excursion in the median nerve and flexor digitorum superficialis muscle were measured during cervical contralateral lateral flexion at 0°, 30°, 60° and 90° of elbow flexion of the upper limb neurodynamic test 1. RESULTS: The cervical movement resulted in proximal excursion and significant changes in strain in the median nerve at 0°, 30° and 60° of elbow flexion during the upper limb neurodynamic test 1 (p < 0.05). In contrast, the structural differentiation manoeuvre did not affect the strain nor the excursion in the muscle at any position of the elbow (p > 0.05). CONCLUSION: Adding CCLF to each ULNT1 median elbow angle increased strain and created proximal excursion of the median nerve at the wrist. Neck movement produced no changes in strain nor excursion of the flexor digitorum superficialis. This study adds to evidence that, in certain circumstances, neck movement may be used in differentiation of nerve and muscle disorders in the wrist.

Effect of ankle dorsiflexion on displacement and strain in the tibial nerve and biceps femoris muscle at the posterior knee during the straight leg raise: Investigation of specificity of nerve movement.

BACKGROUND: A structural differentiation maneuver has been proposed to differentiate between muscle and nerve involvement during the straight leg raise test. However, to date, the mechanical specificity of this maneuver for the tibial nerve at the posterior knee has not been tested. The aim of this study was to investigate the specificity of ankle dorsiflexion as a differentiation maneuver between the tibial nerve and the biceps femoris muscle at the posterior knee during the straight leg raise in cadavers. METHODS: A cross-sectional study was carried out. In fresh frozen cadavers, with microstrain devices and Vernier calipers, strain and excursion in the tibial nerve and distal biceps femoris muscle were measured during ankle dorsiflexion at 0°, 30°, 60° and 90° of hip flexion of the straight leg raise. FINDINGS: Ankle dorsiflexion resulted in significant distal excursion and increased strain in the tibial nerve (p < 0.05) whilst the muscle was not affected by the dorsiflexion (p > 0.05) at all hip flexion angles. INTERPRETATION: Ankle dorsiflexion was mechanically specific between the tibial nerve and biceps femoris during the straight leg raise. This study adds to evidence that, in certain circumstances, dorsiflexion may be used in differentiation of nerve and muscle disorders in the posterior knee.

Differential movement of the sciatic nerve and hamstrings during the straight leg raise with ankle dorsiflexion: Implications for diagnosis of neural aspect to hamstring disorders.

INTRODUCTION: In hamstrings injuries, sciatic nerve and muscle disorders can coexist. Therefore, differential diagnosis to include or exclude nerve involvement is an important aspect of evaluation. The objective of this paper is to investigate the mechanical behaviour of the sciatic nerve and biceps femoris muscle in the proximal thigh with the ankle dorsiflexion manoeuvre at different degrees of hip flexion during the straight leg raise in cadavers. MATERIAL AND METHODS: A cross-sectional study was carried out. Linear displacement transducers were inserted into the sciatic nerve and the biceps femoris muscle of 11 lower extremities from 6 fresh cadavers to measure potential strain of both structures during ankle dorsiflexion at 0°, 30°, 60° and 90° of hip flexion during the straight leg raise. Excursion was also measured with a digital calliper. RESULTS: Ankle dorsiflexion resulted in significant strain and distal excursion of the sciatic nerve at all ranges of hip flexion during the straight leg raise (p < 0.05). In contrast, the ankle movement did not affect the strain in biceps femoris at any position of the hip (p > 0.05). CONCLUSION: Ankle dorsiflexion at different degrees of hip flexion during the straight leg raise produces changes in the strain and excursion of the sciatic nerve in the upper thigh. In contrast, the biceps femoris muscle at the same location was not affected by ankle movement. These findings show differential behaviour between the nerve and muscle with ankle dorsiflexion at this location that could be used as differential diagnosis in posterior hip pain.

Normalization of Spinal Cord Displacement With the Straight Leg Raise and Resolution of Sciatica in Patients With Lumbar Intervertebral Disc Herniation: A 1.5-year Follow-up Study.

STUDY DESIGN: A controlled radiologic follow-up study. OBJECTIVE: The aim of this study was to ascertain whether changes in cord excursion with straight leg raise test (SLR) at 1.5-year follow-up time accompany changes in clinical symptoms. SUMMARY OF BACKGROUND DATA: Lumbar intervertebral disc herniation (LIDH) is known to be a key cause of sciatica. Previously, we found that a significant limitation of neural displacement (66.6%) was evident with the SLR on the symptomatic side of patients with subacute single level posterolateral LIDH. METHODS: Fourteen patients with significant sciatic symptoms due to a subacute single-level posterolateral LIDH were reassessed clinically and radiologically at 1.5 years follow-up with a 1.5T MRI scanner. Displacement of the conus medullaris during the unilateral and bilateral SLR was quantified reliably with a randomized procedure and compared between SLRs and to data from baseline. Multivariate regression models and backward variable selection method were employed to identify variables more strongly associated with a decrease in low back pain (LBP) and radicular symptoms. RESULTS: Compared with previously presented baseline values, the data showed a significant increase in neural sliding in all the quantified maneuvers (P ≤ 0.01), and particularly of 2.52 mm (P ≤ 0.001) with the symptomatic SLR.Increase in neural sliding correlated significantly with decrease of both radicular symptoms (Pearson = -0.719, P ≤ 0.001) and LBP (Pearson = -0.693, P ≤ 0.001). Multivariate regression models and backward variable selection method confirmed the improvement of neural sliding effects (P ≤ 0.004) as the main variable being associated with improvement of self-reported clinical symptoms. CONCLUSION: To our knowledge, these are the first noninvasive data to objectively support the association between increase in magnitude of neural adaptive movement and resolution of both radicular and LBP symptoms in in vivo and structurally intact human subjects. LEVEL OF EVIDENCE: 2.

Dimensional changes of the carpal tunnel and median nerve during manual mobilization of the carpal bones - Anatomical study.

STUDY DESIGN: Cross-sectional study. BACKGROUND: The carpal tunnel is a clinically important fibro-osseous conduit for the median nerve and associated tendons. It is mechanically dynamic and therapeutic manual techniques that appear to move and change tunnel shape is part of clinical practice. OBJECTIVES: To measure changes in dimensions of the carpal tunnel and median nerve with manual mobilization of the carpal bones in cadavers. METHODS: A total of 20 cryopreserved upper extremities from cadaveric specimens were used in the study. The wrist was cut using an anatomical saw at the level of the pisiform. Measurements of the cross-sectional area (CSA), anteroposterior diameter (APD), transverse diameter (TD), perimeter, flattening ratio and circularity of the carpal tunnel and of the median nerve, were taken, both in the anatomical position of the wrist and during the mobilization technique of the carpal bones. RESULTS: During the mobilization technique, the tunnel CSA (p < 0.011), APD (p < 0.001) and circularity (p < 0.001) significantly increased, while TD (p < 0.001), perimeter (p < 0.004) and flattening ratio (p < 0.001), decreased. The median nerve showed similar behavioral tendencies to the tunnel but only the CSA (p < 0.005), APD (p < 0.005) and flattening ratio (p < 0.004) of the nerve showed significant differences. CONCLUSION: Application of external manually applied compressive force across the wrist can increase the CSA of the carpal tunnel and the median nerve in cadavers. These results are consistent with other studies in which similar results were found non-invasively using ultrasound.

Dimensional changes of the carpal tunnel and the median nerve during manual mobilization of the carpal bones.

INTRODUCTION: The carpal tunnel is a clinically important fibro-osseous conduit for the median nerve and associated tendons. It is mechanically dynamic, such that the dimensions of the tunnel and median nerve change with position, movement and application of externally applied force with mechanical devices. Therapeutic manual techniques that appear to move and change tunnel shape are part of clinical practice. The aim of this study was therefore to measure changes in dimensions of the carpal tunnel and median nerve with manual mobilization of the carpal bones. MATERIAL AND METHODS: An analytical descriptive study with 18 volunteer subjects and a total of 33 records was designed. Ultrasound measurements of the cross-sectional area (CSA), anteroposterior diameter (APD), transverse diameter (TD), perimeter, flattening ratio and circularity of the carpal tunnel and of the median nerve, were measured, both in the anatomical position of the wrist and during mobilization techniques of the carpal bones. RESULTS: During the mobilization technique, the tunnel (p = 0.003) CSA significantly increased. APD also increased significantly for the tunnel (<0.001) while TD decreased. The median nerve showed similar and significant (p < 0.001) changes than the tunnel. However, because several of the obtained differences where smaller than the SDD obtained in a previous study, these differences were considered as irrelevant. CONCLUSIONS: Manual mobilization of the carpal bones produced significant changes in the dimensions of the carpal tunnel.

Reliability of measurement of the carpal tunnel and median nerve in asymptomatic subjects with ultrasound.

BACKGROUND: Morphology of the carpal tunnel changes with varying wrist postures and compressive forces applied to the wrist. These changes may affect the morphology and pressure on the median nerve and could be used as part of the treatment of the carpal tunnel syndrome patients. Reliability of the ultrasonographic measurements of the median nerve has been widely studied. However, there is a lack of investigation regarding reliability of ultrasonographic measurements of the carpal tunnel. OBJECTIVE: The purpose of this study was to assess intra-tester and inter-tester reliability of measurement of dimensions of the carpal tunnel and median nerve with ultrasound in asymptomatic volunteers. DESIGN: A cross-sectional methodological study. METHODS: Aspects measured were mediolateral and anteroposterior diameters, flattening ratio, circularity, perimeter and cross-section area of the carpal tunnel and median nerve. RESULTS: Intra-tester reliability was excellent for the carpal tunnel (ICCs from 0.91 to 0.97) and for the median nerve (ICCs from 0.79 to 0.94) measurements. The flattening ratio of the median nerve showed good agreement (ICC = 0.68). Inter-tester reliability was excellent for the carpal tunnel measurements (ICCs from 0.76 to 0.95) and, for the cross sectional area, the perimeter and mediolateral diameter of the median nerve, the ICC values were 0.89, 0.84 and 0.81, respectively. CONCLUSION: In the context of this study, ultrasound was a reliable instrument for measuring carpal tunnel and median nerve dimensions in asymptomatic subjects. LEVEL OF EVIDENCE: 1b.

Reduced Spinal Cord Movement With the Straight Leg Raise Test in Patients With Lumbar Intervertebral Disc Herniation.

STUDY DESIGN: Controlled radiological study. OBJECTIVE: To explore whether impairment of neural excursion during the straight leg raise test occurs in patients with sciatic symptoms secondary to lumbar intervertebral disc herniation (LIDH). SUMMARY OF BACKGROUND DATA: Earlier studies have shown that during the straight leg raise (SLR) test in asymptomatic volunteers tensile forces are consistently transmitted throughout the neural system and the thoracolumbar spinal cord slides distally. METHODS: Fifteen patients with sciatic symptoms due to subacute LIDH were studied with a 1.5 T magnetic resonance scanner. First, a spine specialist diagnosed the LIDH using conventional scanning sequences. Following this subjects were scanned using different scanning sequences for planning and measurement purposes. Displacement of the conus medullaris during the unilateral and bilateral SLR was quantified reliably with a randomized procedure and compared between manoeuvres. RESULTS: The results showed 66.6% less excursion of conus medullaris with SLR performed on the symptomatic side compared with excursions measured with SLR performed on the asymptomatic side (p ≤ 0.001). CONCLUSION: In patients with LIDH, the neural displacement on the symptomatic side is significantly reduced by the compressing IVD herniation. To our knowledge, these are the first data in intact human subjects to support the limitation of neural movements in the vertebral canal with LIDH. LEVEL OF EVIDENCE: 3.

Efficacy of Manual Therapy Including Neurodynamic Techniques for the Treatment of Carpal Tunnel Syndrome: A Randomized Controlled Trial.

OBJECTIVE: The purpose of this randomized trial was to compare the efficacy of manual therapy, including the use of neurodynamic techniques, with electrophysical modalities on patients with mild and moderate carpal tunnel syndrome (CTS). METHODS: The study included 140 CTS patients who were randomly assigned to the manual therapy (MT) group, which included the use of neurodynamic techniques, functional massage, and carpal bone mobilizations techniques, or to the electrophysical modalities (EM) group, which included laser and ultrasound therapy. Nerve conduction, pain severity, symptom severity, and functional status measured by the Boston Carpal Tunnel Questionnaire were assessed before and after treatment. Therapy was conducted twice weekly and both groups received 20 therapy sessions. RESULTS: A baseline assessment revealed group differences in sensory conduction of the median nerve (P < .01) but not in motor conduction (P = .82). Four weeks after the last treatment procedure, nerve conduction was examined again. In the MT group, median nerve sensory conduction velocity increased by 34% and motor conduction velocity by 6% (in both cases, P < .01). There was no change in median nerve sensory and motor conduction velocities in the EM. Distal motor latency was decreased (P < .01) in both groups. A baseline assessment revealed no group differences in pain severity, symptom severity, or functional status. Immediately after therapy, analysis of variance revealed group differences in pain severity (P < .01), with a reduction in pain in both groups (MT: 290%, P < .01; EM: 47%, P < .01). There were group differences in symptom severity (P < .01) and function (P < .01) on the Boston Carpal Tunnel Questionnaire. Both groups had an improvement in functional status (MT: 47%, P < .01; EM: 9%, P < .01) and a reduction in subjective CTS symptoms (MT: 67%, P < .01; EM: 15%, P < .01). CONCLUSION: Both therapies had a positive effect on nerve conduction, pain reduction, functional status, and subjective symptoms in individuals with CTS. However, the results regarding pain reduction, subjective symptoms, and functional status were better in the MT group.

Normal multiplanar movement of the spinal cord during unilateral and bilateral straight leg raise: Quantification, mechanisms, and overview.

The purpose of this investigation was to provide a full set of normal data describing neural biomechanics within the vertebral canal in all three planes with unilateral and bilateral SLR tests to allow for clinical comparison with clinical cases. This is done following the notion that, due to neural continuum, tensile forces are transmitted through the lumbosacral nerve roots and dura to the conus medullaris (linear dependency principle). In this controlled radiologic study 10 asymptomatic volunteers were scanned with 1.5T magnetic resonance scanner (Siemens Magnetom Aera, Erlangen, Germany) using different scanning sequences for planning and for measurement purposes. Conus displacement in both antero-posterior direction (sagittal slices) and lateral direction (axial slices) was quantified during unilateral passive left, right SLR, and bilateral SLR and compared with the position of the conus in the neutral (anatomic) position. It is shown that the conus medullaris displaced laterally and anteroposteriorly in response to unilateral and bilateral SLRs. Pearson's correlations were higher than 0.95 for both intra- and inter-observer reliability. The observed power was higher than 0.99 for all the variables tested. Following this, the authors conclude that lateral and antero-posterior displacement of conus medullaris into the vertebral canal occurs consistently with unilateral and bilateral SLRs following directions predicted by tension vectors. Summative information collected in this line of research in neuroradiology is here presented. We believe we have presented the first conclusive and complete full set of normal data on non-invasive, in vivo, normative measurement of spinal cord displacement with the SLR ever presented. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1335-1342, 2017.

Correlation analysis of demographic and anthropometric factors, hip flexion angle and conus medullaris displacement with unilateral and bilateral straight leg raise.

PURPOSE: It has been shown that the conus medullaris displaces significantly and consistently in response to both unilateral and bilateral SLRs. Point of interest is represented by whether the magnitude of this displacement can be predicted in asymptomatic subjects. The purpose was to investigate whether any correlations existed between demographic and anthropometric factors and hip flexion angle with magnitude of conus medullaris displacement with the unilateral and bilateral SLR. This was done following the notion that there is the possibility that cord movement may contain aspects of predictability in asymptomatic subjects. METHODS: Using the same methods as in our previous MRI studies, we further investigated whether any correlations existed between age, height, weight, BMI or hip flexion angle and magnitude of conus medullaris displacement with the unilateral and bilateral SLR. RESULTS: Moderate to strong positive correlation was found between degree of hip flexion and magnitude of conus medullaris caudal displacement with unilateral and bilateral SLRs and CuMeD. A negligible inverse correlation between subjects' height and magnitude of conus medullaris displacement in response to unilateral SLR was found, while no correlation (r < 0.1) emerged with bilateral SLR and CuMeD. No correlation was found for other values such as age, weight or BMI. CONCLUSIONS: The data show that in in vivo and structurally intact asymptomatic volunteers, the degree of hip flexion may have strong predictive values for magnitude of neural displacement in response to unilateral and bilateral SLRs. This provides further justification to its quantification in clinical settings. Magnitude of conus medullaris displacement in response to unilateral and bilateral SLRs is not likely to be predicted from easily clinically collectable measures such as age, height, weight and BMI. This study offers information relevant to investigation of prediction of neuromechanical responses in neurodynamic tests.

Slump Test: Effect of Contralateral Knee Extension on Response Sensations in Asymptomatic Subjects and Cadaver Study.

STUDY DESIGN: Part 1: A randomized, single-blind study on the effect of contralateral knee extension on sensations produced by the slump test (ST) in asymptomatic subjects. Part 2: A cadaver study simulating the nerve root behavior of part 1. OBJECTIVE: Part 1: Test if contralateral knee extension consistently reduces normal stretch sensations with the ST.Part 2: Ascertain in cadavers an explanation for the results. SUMMARY OF BACKGROUND DATA: In asymptomatic subjects, contralateral knee extension reduces stretch sensations with the ST. In sciatica patients, contralateral SLR also can temporarily reduce sciatica. We studied this methodically in asymptomatic subjects before considering a clinical population. METHODS: Part 1: Sixty-one asymptomatic subjects were tested in control (ST), sham, or intervention (contralateral ST) groups and their sensation response intensity compared.Part 2: Caudal tension was applied to the L5 nerve root of 3 cadavers and tension behavior of the contralateral neural tissue recorded visually. RESULTS: Part 1: Reduction of stretch sensations occurred in the intervention group but not in control and sham groups (P ≤ 0.001).Part 2: Tension in the contralateral lumbar nerve roots and dura reduced in a manner consistent with the responses in the intervention (contralateral ST) group. CONCLUSION: Part 1: In asymptomatic subjects, normal thigh stretch sensations with the ST reduced consistently with the contralateral ST, showing that this is normal and may now be compared with patients with sciatica.Part 2: Contralateral reduction in lumbar neural tension with unilateral application of tension-producing movements also occurred in cadavers, supporting the proposed explanatory hypothesis.

Part 3: Developing Methods of In Vivo MRI Measurement of Spinal Cord Displacement in the Thoracolumbar Region of Asymptomatic Subjects With Unilateral and Bilateral Straight Leg Raise Tests.

STUDY DESIGN: Controlled radiological study. OBJECTIVE: Verify (1) whether conus medullaris displacement varies with the range of hip flexion and (2) whether the acquired data support the "principle of linear dependence." SUMMARY OF BACKGROUND DATA: We have previously quantified normal displacement of the conus with unilateral and bilateral straight leg raise (SLR) and have described the "principle of linear dependence." However, we have since effected methodological advances that have produced data that surpass previous studies. METHODS: Ten asymptomatic volunteers were scanned with a 1.5-T magnetic resonance scanner using T2-weighted spc 3-dimensional scanning sequences and a device that permits greater ranges of SLR. Displacement of the conus medullaris during the unilateral and bilateral SLRs was quantified reliably with a randomized procedure. RESULTS: Pearson correlations were higher than 0.99 for both intra- and interobserver reliability and the observed power was 1 for each tested maneuver. The conus displaced caudally in the spinal canal by 3.54 ± 0.87 mm (µ ± SD) with unilateral (P ≤ 0.001) and 7.42 ± 2.09 mm with bilateral SLR (P ≤ 0.001). CONCLUSION: To the authors' knowledge, these are the first data on noninvasive, in vivo, normative measurement of spinal cord displacement with the SLR test at 60° of hip flexion. Conus medullaris displacement increased with hip flexion angle, while maintaining the relationship between magnitude of conus displacement and number of nerve roots involved into the movement, supporting the "principle of linear dependence." The use of T2-weighted spc 3-dimensional sequence allows for better reliability testing, which is important for future clinical utility. LEVEL OF EVIDENCE: 5.