A Novel Surgical Landmark to Identify the Recurrent Laryngeal Nerve

Background: Although several surgical landmarks have been proposed to localize the recurrent laryngeal nerve (RLN), there is still no reliable landmark. Aims: To validate the reliability of a novel reference point at the intersection of the inferior border of the cricopharyngeal muscle and the inferior cornu of thyroid cartilage for locating the RLN. Study Design: Cadaver dissection study in the academic department of otolaryngology-head and neck surgery. Methods: Sixty-four RLNs in cadavers were assessed, and measurements of different surgical landmarks in conjunction with the proposed surgical landmark were obtained. Descriptive statistics, Pearson's chi-squared test, and Student's t-test were performed to analyze the data using GraphPad Prism (version 9.4.1; Dotmatics, Boston, Massachusetts, USA). Results: The average distance from the proposed landmark to the RLN was 2.3 ± 0.85 mm. The RLN was located just posterior to the reference point in 95.31% of the cadavers. The RLN passed under the inferior constrictor muscle in 90.63% of the cadavers. There was no statistically significant difference between right- and left-sided RLNs in terms of their relation with the reference point. Conclusion: The proposed reference point can be used as a reliable landmark to locate the RLN. This reference point may help surgeons during difficult thyroidectomy surgeries by providing an additional anatomical landmark.

Upper limb neurodynamic mobilization disperses intraneural fluid in cervical nerve roots: A human cadaveric investigation.

BACKGROUND: Cervical radiculopathy is a common cause of neck pain with resultant intraneural edema and impaired nerve function. One strategy to treat radiculopathy is neurodynamic mobilization (NDM); however, little is known about the effect of this treatment on nerve tissue fluid dynamics. OBJECTIVE: Investigate the impact of upper limb, median nerve-biased NDM on longitudinal intraneural fluid dispersion in the C5,C6,C7 nerve roots in un-embalmed cadavers. DESIGN: In situ repeated measures. METHODS: Human cadavers (n = 8) were dissected to expose and inject C5,C6,C7 cervical nerve roots with a dying agent. Initial longitudinal dye spread was recorded after dye spread stabilization. Cadavers were taken through 150 repetitions of upper limb, median nerve-biased NDM followed by dye spread re-measurement. Paired-samples t-tests with Bonferroni correction (α = 0.017) were used to compare pre-vs post-NDM dye spread measurements at C5,C6,C7 nerve roots; a one-way repeated measures ANOVA (α = 0.05) was used to examine differences between change scores for C5,C6,C7 nerve roots. RESULTS: Median nerve-biased NDM resulted in significant intraneural longitudinal dye spread at C5 and C6 nerve roots of 0.6 ± 0.6 mm and 3.4 ± 3.9 mm, respectively (p < 0.014). Dye spread was not significant at C7 nerve root (0.4 ± 0.7 mm). There was no between root difference in change of longitudinal dye spread between C5, C6, and C7 nerve roots. CONCLUSIONS: The results of this study show median nerve-biased NDM produced internal fluid movement within C5 and C6 cervical nerve roots. Results provide insight regarding possible mechanism of action and feasibility of NDM in treatment of patients with cervical radiculopathy.

Biomechanical Strength of a Novel Tendon Splicing Open Book Technique Compared to the Pulvertaft Method Using Unembalmed Human Cadaveric Tissue.

Background: Extensor pollicis longus (EPL) tendon rupture is a known complication of distal radius fractures. The Pulvertaft graft technique is currently used for tendon transfer of extensor indicis proprious (EIP) to EPL. This technique can produce unwanted tissue bulkiness and cosmetic concerns as well as hinder tendon gliding. A novel "open book" technique has been proposed, but relevant biomechanical data are limited. We designed a study to examine the biomechanical behaviours of the "open book" versus Pulvertaft techniques. Methods: Twenty matched forearm-wrist-hand samples were harvested from 10 fresh frozen cadavers (2 female, 8 male) with a mean age of 61.7 (±19.25) years. The EIP was transferred to EPL using the Pulvertaft versus "open book" techniques for each matched pair (sides randomly assigned). The repaired tendon segments were mechanically loaded using a Materials Testing System to examine graft biomechanical behaviours. Results: Mann-Whitney U test outcomes demonstrated that there was no significant difference between "open book" versus Pulvertaft techniques for peak load, load at yield, elongation at yield, or repair width. The "open book" technique demonstrated a significantly lower elongation at peak load and repair thickness, as well as significantly higher stiffness when compared with the Pulvertaft technique. Conclusions: Our findings support the use of the "open book" technique, producing comparable biomechanical behaviours compared to the Pulvertaft technique. Incorporating the "open book" technique potentially requires smaller repair volume, producing size and appearance that is more anatomic when compared with the Pulvertaft.

Contexte: La rupture du tendon du long extenseur du pouce (EPL - Extensor pollicis longus) est une complication connue des fractures distales du radius. La technique de greffe de Pulvertaft est actuellement utilisée pour un transfert tendineux de l'extenseur propre de l'index (EIP - extensor indicis proprious) à l'EPL. Cette technique peut produire une masse de tissu volumineuse non désirée et des préoccupations cosmétiques, mais aussi gêner le glissement du tendon. Une nouvelle technique en « livre ouvert ¼ a été proposée, mais les données biomécaniques pertinentes sont limitées. Nous avons conçu une étude visant à examiner les comportements biomécaniques de la technique « en livre ouvert ¼ comparativement à la technique de Pulvertaft. Méthodes: Vingt échantillons appariés avant-bras-poignet-main ont été prélevés sur 10 cadavres récemment congelés (2 femmes, 8 hommes) d'âge moyen 61,7 (± 19,25) ans. Les EIP ont été transférés aux EPL en utilisant la technique de Pulvertaft et la technique en livre ouvert pour chaque paire appariée (l'affectation du côté à chaque technique a été faite de manière aléatoire). Les segments tendineux réparés ont été chargés mécaniquement au moyen d'un système pour tester les matériaux afin d'étudier les comportements biomécaniques des greffes. Résultats: Les résultats du test U de Mann-Whitney ont montré qu'il n'y avait pas de différence significative entre la technique « en livre ouvert ¼ et la technique de Pulvertaft pour la charge maximum, la charge à la limite apparente d'élasticité, l'allongement à la limite apparente d'élasticité ou la largeur de réparation. La technique « en livre ouvert ¼ a démontré un allongement à la charge maximum et une épaisseur de réparation significativement moindres, ainsi qu'une significativement plus grande raideur, comparativement à la technique de Pulvertaft. Conclusions: Nos constatations étayent l'utilisation de la technique « en livre ouvert ¼ qui procure des comportements biomécaniques comparables à ceux de la technique de Pulvertaft. L'incorporation de la technique « en livre ouvert ¼ requiert potentiellement un plus petit volume de réparation, aboutissant à des dimensions et à un aspect plus anatomiques par rapport à la technique de Pulvertaft.

Correlation between thoracic kyphosis and dry needle length required to reach the pleural space needling the upper trapezius: A cadaveric fluoroscopic assessment.

BACKGROUND: It is unknown whether greater prone thoracic kyphosis increases pneumothorax risk during upper trapezius dry needling. OBJECTIVES: To fluoroscopically assess for a correlation between prone thoracic kyphosis and needle length required to reach the pleural space dry needling the upper trapezius in prone. DESIGN: Cadaveric study. METHODS: Prone thoracic kyphosis was assessed using dual bubble inclinometers. A 30 mm dry needle was inserted into the midsubstance of the upper trapezius perpendicular to the thoracic kyphosis. A single C-arm fluoroscopic image was obtained. This procedure was repeated with 40, 50, and 60 mm needles. Images were independently viewed by a radiologist to make a binary decision (yes vs. no) whether the needle had potentially broached the pleural space. RESULTS: Fifteen cadaveric specimens with a mean age of 74.9 ± 9.7 and mean kyphosis of 21.5° ±7.7 were used. A 30 mm needle never reached the pleural space. The pleural space was potentially broached on one, four and six occasions by the 40, 50, and 60 mm needle respectively. The correlation between needle depth penetration and kyphosis was not significant (r = 0.03, p = 0.93). Longer needles (50 and 60 mm) were significantly (p = 0.0049) more likely to reach the pleural space than shorter needles (30 and 40 mm). CONCLUSION: Thoracic kyphosis was not correlated with needle length required to reach the pleural space. Clinicians may consider selecting shorter needles (<40 mm) to mitigate potential risk while dry needling the upper trapezius in prone.

Influence of clinical experience on accuracy and safety of obliquus capitus inferior dry needling in unembalmed cadavers.

BACKGROUND: Suboccipital myofascial trigger points are common in tension-type headaches. OBJECTIVES: Compare the influence of clinical experience on the accuracy and safety of dry needle placement on the C2 laminar arch using a cranial-medial and caudal-medial technique to target obliquus capitus inferior in unembalmed cadavers. METHODS: Three physical therapists inserted three 50 mm dry needles, per technique, individually toward the C2 laminar arch targeting the obliquus capitus inferior. Ultrasound video of each trial was recorded, and an investigator trained in ultrasound interpretation and blinded to experience level recorded needling accuracy. RESULTS: The novice, experienced and expert clinicians were accurate on 73.8%, 59.5% and 71.4% of caudal-medial trials, and 14.3%, 16.7% and 66.7% of cranial-medial trials, respectively, with each clinician striking the spinal cord at least once. The expert clinician was 10 times more likely to accurately reach the C2 laminar arch using the cranial-medial direction than the experienced and novice clinicians. CONCLUSION: Increased clinical experience improved accuracy reaching the C2 laminar arch, with all investigators being more accurate with the caudal-medial technique. Greater experience did not eliminate risk as all investigators recorded at least one incident of striking the spinal cord. Fewer spinal cord strikes occurred with the cranial-medial than the caudal-medial technique.

Upper limb neurodynamic testing with radial and ulnar nerve biases: An analysis of cervical spinal nerve mechanics.

BACKGROUND: Clinical research supports a combination of upper limb neurodynamic testing (ULNT) strategies to rule out upper limb and cervical neurogenic pathology; however, knowledge of the biomechanical response of spinal nerves during ULNT is lacking for radial and ulnar nerve biases. OBJECTIVE: To assess whether radial and ulnar nerve biased strategies of ULNT elicit significant displacement and strain of cervical spinal nerves. STUDY DESIGN: Cross-sectional. METHODS: Radiolucent markers were implanted into spinal nerves C5-C8 proximal and distal to the intervertebral foramen in nine unembalmed cadavers (six male; three female) age 80.1 ± 13.2 years. Fluoroscopic images were captured during ULNT with radial and ulnar nerve biases. Images at rest and maximum tension were digitized and displacement and strain were measured. All data were analyzed using one sample t-tests and a generalized linear mixed models approach. RESULTS: Upper limb neurodynamic testing with radial nerve bias resulted in displacement (2.44-3.04 mm) and strain (7.99-11.98%) and ULNT with ulnar nerve bias resulted in displacement (2.16-4.41 mm) and strain (7.12 and 12.95%). Significant extraforaminal displacement occurred during radial and ulnar nerve biases for all spinal nerves (all P < 0.05) whereas significant strain occurred during ulnar nerve biases for all spinal nerves but only in C6-C8 during radial nerve bias. CONCLUSION: Upper limb neurodynamic testing using both radial and ulnar nerve biases resulted in cervical spinal nerve displacement and strain. Such techniques could be used to tension load or mobilize or cervical spinal nerves to evaluate for pathology.

The relationship between measures of foot mobility and subtalar joint stiffness using vibration energy with color Doppler imaging-A clinical proof-of-concept validation study.

INTRODUCTION: Subtalar joint (STJ) dysfunction can contribute to movement disturbances. Vibration energy with color Doppler imaging (VECDI) may be useful for detecting STJ stiffness changes. OBJECTIVES: (1) Support proof-of-concept that VECDI could detect STJ stiffness differences; (2) Establish STJ stiffness range in asymptomatic volunteers; (3) Examine relationships between STJ stiffness and foot mobility; and (4) Assess VECDI precision and reliability for examining STJ stiffness. METHODS: After establishing cadaveric testing model proof-of-concept, STJ stiffness (threshold units, ΔTU), ankle complex passive range-of-motion (PROM) and midfoot-width-difference (MFWDiff) data were collected in 28 asymptomatic subjects in vivo. Three reliability measurements were collected per variable; Rater-1 collected on all subjects and rater-2 on the first ten subjects. Subjects were classified into three STJ stiffness groups. RESULTS: Cadaveric VECDI measurement intra-rater reliability was 0.80. A significantly lower STJ ΔTU (p = .002) and ankle complex PROM (p < .001) was observed during the screw fixation versus normal condition. A fair correlation (r = 0.660) was observed between cadaveric ΔTU and ankle complex PROM. In vivo VECDI measurements demonstrated good intra-rater (0.76-0.84) versus poor inter-rater (-3.11) reliability. Significant positive correlations were found between STJ stiffness and both dorsum (r = .440) and posterior (r = .390) PROM. MFWDiff exhibited poor relationships with stiffness (r = .103) and either dorsum (r = .256) or posterior (r = .301) PROM. STJ stiffness ranged from 2.33 to 7.50 ΔTUs, categorizing subjects' STJ stiffness as increased (n = 6), normal (n = 15), or decreased (n = 7). Significant ANOVA main effects for classification were found based on ΔTU (p< .001), dorsum PROM (p = .017), and posterior PROM (p = .036). Post-hoc tests revealed significant: (1) ΔTU differences between all stiffness groups (p < .001); (2) dorsum PROM differences between the increased versus normal (p = .044) and decreased (p = .017) stiffness groups; and (3) posterior PROM differences between the increased versus decreased stiffness groups (p = .044). A good relationship was found between STJ stiffness and dorsum PROM in the increased stiffness group (r = .853) versus poor, nonsignificant relationships in the normal (r = -.042) or decreased stiffness (r = -.014) groups. CONCLUSION: PROM may not clinically explain all aspects of joint mobility. Joint VECDI stiffness assessment should be considered as a complimentary measurement technique.

THE TENSILE BEHAVIORS OF THE ILIOTIBIAL BAND - A CADAVERIC INVESTIGATION.

BACKGROUND: Clinical stretching is frequently recommended for iliotibial band syndrome management. Current literature lacks conclusive findings regarding isolated human iliotibial band tissue elongation and stiffness behaviors. Applying clinical-grade stretching force results to iliotibial band tissue behavior is thus challenging. PURPOSE: This study's objectives were to determine isolated iliotibial band tissue tensile behaviors during tension-to-failure testing and to relate the results to previously reported iliotibial band stretch findings. STUDY DESIGN: Descriptive in vitro laboratory study. METHODS: Ten isolated un-embalmed iliotibial band specimens were exposed to tension-to-failure testing using a 10kN material testing system. Peak load, load at yield point, and ultimate failure load were measured in Newtons. Corresponding absolute (mm) and relative (%) tissue deformation was recorded. Load-deformation curves were established to calculate iliotibial band stiffness (N/mm). RESULTS: A mean peak load of 872.8 ± 285.9N and resulting 9.0 ± 3.9% tissue deformation from initial length was recorded. An 805.5 ± 249.7N mean load at yield point and resulting 7.0 ± 1.9% tissue deformation was observed. A 727.6 ± 258.4N mean load was recorded directly prior to ultimate tissue failure. Mean tissue deformation at ultimate failure was 11.3 ± 4.2%. Mean iliotibial band system stiffness was 27.2 ± 4.5N/mm. CONCLUSION: The iliotibial band can withstand substantial tensile forces. Clinical stretching forces likely fall within the load-deformation curve elastic region and may not result in permanent iliotibial band tissue deformation. Sustained elongation resulting from stretching the ITB may require substantial patient compliance. Future studies should investigate potential underlying factors related to positive symptom relief from iliotibial band stretching that include immunological responses, fluid accumulation, altered proprioception, and pain perception. LEVEL OF EVIDENCE: 3.

Accuracy of unguided and ultrasound guided Coracohumeral ligament infiltrations - a feasibility cadaveric case series.

BACKGROUND: Coracohumeral ligament (CHL) thickening, contracture, and fibroplasia have been identified in glenohumeral idiopathic adhesive capsulitis (GHIAC). The CHL is the main structure responsible for the range of motion limitations. Favorable outcomes have been reported with CHL surgical release. Intra-articular glenohumeral joint corticosteroid infiltrations are utilized to disrupt the inflammatory process and reduce pain in GHIAC. The aim of this study was to investigate whether the CHL could be accurately targeted with a periligamentous infiltration. METHODS: A convenience sample of 12 unembalmed cadaver shoulders (mean age: 74.5 years, range 66-87 years) without evidence of previous injury or surgery were utilized in this exploratory double factor feasibility cadaveric (unguided and ultrasound (US) guided) case series. Two clinicians trained in musculoskeletal infiltration techniques carried out the infiltrations on each shoulder with colored latex. One clinician infiltrated without guidance, the other with US-guidance. The injecting clinicians were blinded to the others infiltration procedure and the order was randomized. An anatomist blinded to the infiltration order performed a shoulder dissection and recorded the infiltrate location. Percentage calculation for accuracy of infiltration and a chi-square evaluation of the difference between unguided and US-guided infiltrations was applied. RESULTS: An accuracy of 75% was achieved for unguided infiltration and 80% for US-guided infiltration techniques. Chi-squared indicated there was no significant difference (p = 0.82) between the unguided and US-guided techniques. CONCLUSION: US-guided and unguided infiltrations achieved good accuracy targeting the CHL, suggesting infiltrations can specifically and accurately target the CHL. In vivo investigation using such infiltration techniques are warranted.

Glenohumeral joint capsular tissue tension loading correlates moderately with shear wave elastography: a cadaveric investigation.

PURPOSE: The purpose of this study was to investigate changes in the mechanical properties of capsular tissue using shear wave elastography (SWE) and a durometer under various tensile loads, and to explore the reliability and correlation of SWE and durometer measurements to evaluate whether SWE technology could be used to assess tissue changes during capsule tensile loading. METHODS: The inferior glenohumeral joint capsule was harvested from 10 fresh human cadaveric specimens. Tensile loading was applied to the capsular tissue using 1-, 3-, 5-, and 8-kg weights. Blinded investigators measured tissue stiffness and hardness during loading using SWE and a durometer, respectively. Intraobserver reliability was established for SWE and durometer measurements using intraclass correlation coefficients (ICCs). The Pearson product-moment correlation was used to assess the associations between SWE and durometer measurements. RESULTS: The ICC3,5 for durometer measurements was 0.90 (95% confidence interval [CI], 0.79 to 0.96; P<0.001) and 0.95 (95% CI, 0.88 to 0.98; P<0.001) for SWE measurements. The Pearson correlation coefficient values for 1-, 3-, and 5-kg weights were 0.56 (P=0.095), 0.36 (P=0.313), and -0.56 (P=0.089), respectively. When the 1- and 3-kg weights were combined, the ICC3,5 was 0.72 (P<0.001), and it was 0.62 (P<0.001) when the 1-, 3-, and 5-kg weights were combined. The 8-kg measurements were severely limited due to SWE measurement saturation of the tissue samples. CONCLUSION: This study suggests that SWE is reliable for measuring capsular tissue stiffness changes in vitro at lower loads (1 and 3 kg) and provides a baseline for the non-invasive evaluation of effects of joint loading and mobilization on capsular tissues in vivo.

Anatomical relationship of palmar carpal bone landmarks used in locating the lunate and capitate during palpation: A cadaveric investigation.

STUDY DESIGN: Descriptive in situ cadaveric study. INTRODUCTION: Performing accurately directed examination and treatment to the wrist requires clinicians to orient to carpal bone structures. PURPOSE OF THE STUDY: To examine the anatomical relationships that exist within the wrist-hand complex and identify the accuracy of surface anatomy mapping strategies for localizing anatomical landmarks using a palmar approach. METHODS: Twenty-three embalmed cadavers were dissected using standardized procedures. Metal markers were placed in the most prominent palmar landmark of key carpal structures. Relationships between the most prominent palpation landmarks and the carpal bones of interest were visualized using fluoroscopy. RESULTS: The most successful methods of palmar capitate localization included the midpoint of a line from trapezium tubercle to pisiform; the midpoint of a line from scaphoid tubercle to hamate hook; or the intersection (cross) of these 2 diagonal lines, with successful capitate identification 100% (23/23) of the time. The most successful method for locating the lunate included the midpoint of a line from the radial styloid process to the ulnar styloid process, which identified the lunate in 100% (23/23) of cases. DISCUSSION: The results of this cadaveric anatomical relationship study support the use of the midpoint of a line from pisiform to trapezium tubercle, the midpoint of a line from scaphoid tubercle to hamate hook, or a combination (cross) of these lines to locate the capitate from a palmar approach. In addition, the anatomical relationships examined in this study support the use of the midpoint of a line from the radial styloid process to ulnar styloid process to locate the lunate from a palmar approach. Knowledge of these anatomical relationships may improve the clinician's confidence in locating the capitate and lunate during intercarpal examination, special testing, and treatment. CONCLUSION: Results of this study provide information of the anatomical relationships of the carpal bones from a palmar approach, giving clinicians a foundation for proper orientation to the carpal bones during clinical examination and intervention. Further research is needed to evaluate the reliability and accuracy of these methods for surface palpation on live patients.

Accuracy and safety of dry needle placement in the piriformis muscle in cadavers.

OBJECTIVES: The purpose of this anatomic investigation is to (1) establish accuracy of dry needle placement into the medial third of the piriformis muscle as it exits the pelvis from the greater sciatic notch in unembalmed cadaveric specimens, while avoiding puncture of the sciatic nerve, and (2) establish guidelines for dry needle length selection. METHODS: Dry needles were placed in nineteen unembalmed cadaveric posterior hips. Dissection of the posterior hip musculature was performed to confirm location of the needle. A binary decision (yes/no) was made to determine whether the needle reached the piriformis muscle, went through the piriformis muscle, and/or pierced the sciatic nerve. Additionally, mean adipose tissue thickness, gluteus maximus muscle thickness, and perpendicular distance from the needle to the exiting sciatic nerve were recorded. RESULTS: The needle reached the medial third of the piriformis in 16 out of 19 hips (84.2% accuracy) and never punctured the sciatic nerve. There was a fair (r = 0.493) and good (r = 0.759) correlation between the needle length and the mean fat thickness for the left and right hips, respectively. DISCUSSION: A physical therapist was able to use bony landmark palpation to locate the piriformis muscle and use estimated adipose tissue thickness to choose a sufficient needle length to reach the medial third of the piriformis muscle. While the needle placement technique was safe and no sciatic nerve puncture occurred, the proximity of the piriformis muscle to the sciatic nerve warrants caution during needle placement. LEVEL OF EVIDENCE: 2c.

DEFORMATION RESPONSE OF THE ILIOTIBIAL BAND-TENSOR FASCIA LATA COMPLEX TO CLINICAL-GRADE LONGITUDINAL TENSION LOADING IN-VITRO.

BACKGROUND: Iliotibial Band (ITB) syndrome is a troublesome condition with prevalence as high as 12% in runners. Stretching has been utilized as a conservative treatment. However, there is limited evidence supporting ITB elongation in response to a stretching force. PURPOSE/HYPOTHESES: The purpose of this study was to describe the iliotibial band tensor fascia lata complex (ITBTFLC) tissue elongation response to a simulated clinical stretch in-vitro. The authors hypothesized that the ITBTFLC would undergo statistically significant elongation when exposed to a clinical-grade stretching regimen, with the majority of the elongation occurring within the proximal ITBTFLC region. STUDY DESIGN: Within subjects repeated measures in-vitro design. METHODS: The strain response of six un-embalmed ITBTFLCs to a simulated clinical stretch of 2.75% elongation was assessed. Four sets of array marks were placed along the length of the ITBTFLC. Photographic images were taken in resting position (with 1.0% in-situ elongation) and with an additional 2.75% elongation. Tissue elongation was compared between proximal, middle, and distal ITBTFLC regions. RESULTS: A paired samples t-test demonstrated a significantly longer ITBTFLC in the "stretched" versus resting condition (p = 0.001). Significant elongation was observed in the proximal (3.96mm (SD = 1.35); p = 0.001), middle (2.12mm (SD = 1.49); p = 0.018) and distal (2.25mm (SD = 1.37); p = 0.01) regions during the "stretched" versus the resting condition. A one-way ANOVA demonstrated a significant main effect for region (p = 0.002). The proximal region exhibited significantly greater elongation versus the middle (p = 0.003) and distal (p = 0.007) regions, with no significant difference between the middle and distal regions (p = 0.932). CONCLUSION: The results of this study demonstrate that the ITBTFLC is capable of elongation in response to a clinically simulated stretch. The proximal ITB region underwent significantly greater elongation than the middle and distal regions and may be more likely to respond to "stretching" in clinical situations. Future investigation should assess the ITBTFLC load/deformation properties to determine whether a short-term clinically available stretch translates into permanent tissue elongation. LEVEL OF EVIDENCE: III.

Dynamic balance as measured by the Y-Balance Test is reduced in individuals with low back pain: A cross-sectional comparative study.

OBJECTIVES: To determine the effects of current LBP (cLBP) and LBP history (hxLBP) on Y-Balance Test (YBT) reach and establish relationships between YBT performance and demographic, behavioral, and disability measures. DESIGN: Cross-sectional comparative study. SETTING: Research laboratory. PARTICIPANTS: Forty-two participants (24 males, 18 females) aged 18-50 years (30.9 ± 8.2 yr) in three groups: cLBP, hxLBP, and healthy controls. INTERVENTIONS: Three YBT trials in anterior (ANT), posterolateral (PL), and posteromedial (PM) directions. MAIN OUTCOME MEASURES: YBT reach (relative to leg length) was measured and compared amongst groups. Pearson correlations were calculated between reach distances and pain, disability, and fear avoidance scores in the cLBP and hxLBP groups and age and activity level in all participants. RESULTS: For PL reach, cLBP (94.7 ± 10.6 cm) and hxLBP (94.2 ± 9.2 cm) groups demonstrated shorter distances versus controls (105.8 ± 6.6 cm). For PM reach, cLBP (100.7 ± 8.4 cm) and hxLBP (102.3 ± 7.6 cm) groups' distances were shorter versus controls (109.3 ± 6.7 cm). No significant difference was found for ANT reach (control = 66.4 ± 7.0 cm; cLBP = 66.2 ± 6.2 cm; hxLBP = 66.4 ± 3.1 cm). No significant correlations were identified. CONCLUSION: YBT performance is reduced in individuals with cLBP and hxLBP in the PL and PM directions but not ANT. The YBT is useful for measuring balance deficits in these populations.

Reliability and validation of in vitro lumbar spine height measurements using musculoskeletal ultrasound: A preliminary investigation.

BACKGROUND: Stadiometry measures total trunk height variations but cannot quantify individual spinal segment height changes. Different methods exist to measure both intervertebral disc and lumbar spine height (LSH) variations but they are either limited by radiation exposure or cost. Musculoskeletal ultrasound could be a valuable alternative to measure spinal segmental height changes as a result of intervention. OBJECTIVE: To validate the use of musculoskeletal ultrasound (MSU) and new anatomical landmark references used in assessing inter-mammillary distances (IMD) and LSH changes resulting from lumbar spine traction. METHODS: Two unembalmed cadaveric lumbar spines were extracted to assess (1) the reliability and validity of MSU, as compared to caliper, for measuring in vitro IMD and LSH using alternative anatomical landmarks than previously reported, and (2) the reliability of MSU for measuring in vitro IMD and lumbar spine height changes recorded during standardized mechanical traction up to 1.20 cm. RESULTS: Intra- and inter-rater reliability of musculoskeletal ultrasound for within and between sessions and for all experimental design, Standard Error ranged from 0.01 to 0.02 and from 0.03 to 0.04 cm for IMDs and LSHs, respectively. Root Mean Square Errors ranged from 1.6 to 6.8% and from 1 to 1.1% for IMDs and LSHs, respectively and mean ICC ranged from 0.98 to 1 for LSH. During traction, mean lumbar spine height measurement change using MSU was 1.15 ± 0.03 cm. Bland and Altman plots demonstrated confidence intervals included in the limits of agreement. Nevertheless, there were significant differences (p< 0.001) for both IMD measurements and lumbar spine height between caliper and ultrasound measurements. Musculoskeletal ultrasound overestimated distances of about 5.5 ± 1.5%. CONCLUSIONS: Musculoskeletal ultrasound is reliable and accurate for measuring intersegmental spinal distances and lumbar spine height with an apparent slight overestimation of distances. Based on mean differences, ultrasound technology seems to be valid for measuring lumbar spine height changes and could be suitable for in vivo research.

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.

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

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.

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.

The relationship between various anatomical landmarks used for localizing the first rib during surface palpation.

OBJECTIVES: To assess the relationship between anatomical landmarks used to locate the first rib during surface palpation. One currently cited technique suggests locating the width of the transverse processes (TPs) of the first cervical vertebrae (C1) to determine the estimated width of the first thoracic vertebrae (T1) TP, allowing for subsequent palpation of the first rib laterally to the transverse process of T1. Based on anatomical structural relationships, the authors propose an additional method of locating the first rib, lateral to T1 TP, by palpating through the trapezius muscle at the width of the mastoid process (MP). METHODS: Overlying tissue of the bilateral MP, C1 TPs, and T1 TPs of 28 cadavers were removed. Measurements of the left to right spans at the following structures were collected using a digital caliper: mastoid process, C1 TP, and T1 TP. Measurements were used to determine the agreement between each anatomical structural span. RESULTS: The mean absolute difference (standard deviation, SD) between C1 TP span versus T1 TP span was 3.9 (±2.58) mm with an intraclass correlation coefficient (ICC) of 0.88 (95% CI = 2.9-4.9). The mean absolute difference between MP span and T1 TP span was 35.4 (±6.46) mm with an ICC of 0.71 (95% CI = 33.0-37.8). DISCUSSION: This study confirms the anatomical accuracy and feasibility of using the C1 TP span to determine the general width of the T1 TP span while palpating for the first rib just lateral to the T1 TP. Additionally, this study demonstrates that the more easily palpated mastoid process serves as an effective landmark to identify a width sufficiently lateral to the T1 TP, appropriate for first rib palpation through the trapezius muscle.