Another (Internal) Epineurium: Beyond the Anatomical Barriers of Nerves

Sciatic nerve fascicle differentiation on high-resolution ultrasound with histological verification: An ex vivo study

INTRODUCTION/AIMS

The development of high-resolution ultrasound (HRUS) has enabled the depiction of peripheral nerve microanatomy in vivo. This study compared HRUS fascicle differentiation to the structural depiction in histological cross-sections (HCS).

METHODS

A human cadaveric sciatic nerve was marked with 10 surgical sutures, and HRUS image acquisition was performed with a 22-MHz probe. The nerve was excised and cut into five segments for HCS preparation. Selected HCS were cross-referenced to HRUS, with sutures to improve orientation. Sciatic nerve and fascicle contouring were performed to assess nerve and fascicular cross-sectional area (CSA), fascicle count, and interfascicular distances. Three groups were defined based on HRUS fascicle differentiation in comparison to HCS, namely single fascicle (SF), fascicular cluster (FC), and no depiction (ND) group.

RESULTS

On cross-referenced HRUS to HCS images, 58% of fascicles were differentiated. On HRUS, significantly larger fascicle CSA and smaller fascicle count were observed compared with HCS. Group analysis showed that 41% of fascicles were defined as SF, 47% as FC, and 12% as ND. The mean fascicle CSA in the ND group was 0.05 mm2. Compared with the SF, the FC had significantly larger fascicle CSA (1.2 ± 0.7 vs. 0.6 ± 0.4 mm2; p < .001) and shorter interfascicular distances (0.1 ± 0.04 vs. 0.5 ± 0.3 μm; p < .001).

DISCUSSION

While HRUS can depict fascicular anatomy, only half of the fascicles visualized on HRUS directly correspond to single fascicles observed on HCS. The amount of interfascicular epineurium appears to influence the ability of HRUS to differentiate individual fascicles.

Nerve block, nerve damage, and fluid injection pressure: overturning the myth

Histological and micro-ultrasound evidence rebuffs deep-rooted views on the nature of nerve block, nerve damage, and injection pressure monitoring. We propose that the ideal position of the needle tip for nerve block is between the innermost circumneural fascial layer and outer epineurium, with local anaesthetic passing circumferentially through adipose tissue. Thin, circumferential, subepineural expansion that is invisible to the naked eye was identified using micro-ultrasound, and could account for variability of outcomes in clinical practice. Pressure monitoring cannot differentiate between intrafascicular and extrafascicular injection. High injection pressure only indicates intraneural extrafascicular spread, not intrafascicular spread, because it is not possible to inject into the stiff endoneurium in most human nerves.

Recent advances in enhances peripheral nerve orientation: the synergy of micro or nano patterns with therapeutic tactics

Several studies suggest that topographical patterns influence nerve cell fate. Efforts have been made to improve nerve cell functionality through this approach, focusing on therapeutic strategies that enhance nerve cell function and support structures. However, inadequate nerve cell orientation can impede long-term efficiency, affecting nerve tissue repair. Therefore, enhancing neurites/axons directional growth and cell orientation is crucial for better therapeutic outcomes, reducing nerve coiling, and ensuring accurate nerve fiber connections. Conflicting results exist regarding the effects of micro- or nano-patterns on nerve cell migration, directional growth, immunogenic response, and angiogenesis, complicating their clinical use. Nevertheless, advances in lithography, electrospinning, casting, and molding techniques to intentionally control the fate and neuronal cells orientation are being explored to rapidly and sustainably improve nerve tissue efficiency. It appears that this can be accomplished by combining micro- and nano-patterns with nanomaterials, biological gradients, and electrical stimulation. Despite promising outcomes, the unclear mechanism of action, the presence of growth cones in various directions, and the restriction of outcomes to morphological and functional nerve cell markers have presented challenges in utilizing this method. This review seeks to clarify how micro- or nano-patterns affect nerve cell morphology and function, highlighting the potential benefits of cell orientation, especially in combined approaches.

Analysis of the Characteristics and Intricacies of Arrangement of Neural Elements in the Costoclavicular Block Using Ultrasound: A Retrospective Qualitative Study

Background

Ultrasound (US)-guided costoclavicular block (CCB) is a promising new approach to brachial plexus (BP) block which is increasingly being utilized. Conventionally, the costoclavicular space (CCS) has been described to contain three cords. However, there may be variations in the neural pattern of the BP which is important to know to prevent inadvertent injury. We intend to describe the variations in neural patterns from retrospective scans of patients receiving costoclavicular BP block.

Methods

The stored US images of patients who had received BP block using the CCB for surgery at the level of the elbow or below in the last year (from March 2021 to March 2022) were analyzed by two investigators independently. The clinical data were retrieved from the records of the same patients for the study outcomes. We collated the variations of the neural pattern, the number of neural structures seen, and the echogenicity of the structures in the costoclavicular BP space.

Results

In the CCS, the median number of neural structures was 4.5 (minimum of 3 to maximum of 8). With the BP lateral to the axillary artery and sandwiched between the subclavius-pectoralis minor superiorly and the serratus anteriorly inferiorly, numerous variations in the neural structures were noted. The most common arrangement was caterpillar-like (28.6%) and pecker-like (20.3%). The neural structures were found to be hypoechoic in the majority (66%).

Conclusion

The CCS hosts several mostly hypoechoic neural structures which may be the variations of the cords or the extension of BP divisions. These new findings have been unreported in the recent past.

Dislodgment of continuous suprascapular nerve block catheters after physiotherapy: A cadaver study

BACKGROUND

Continuous peripheral nerve blocks are commonly used for pain management. However, the incidence of catheter dislodgement or migration is unclear, and may be underestimated and underreported. Our objective was to assess suprascapular catheter tip positioning before and after routine simulated shoulder physiotherapy manipulation in an anatomical cadaver model.

METHOD

Eight ultrasound-guided continuous suprascapular nerve block catheters were placed in cryopreserved fresh cadavers. Computed tomography (CT) confirmed the location of the catheter tip after injection of 1 ml of contrast medium. We performed a series of standardized shoulder movements during a simulated shoulder physiotherapy session in cadavers. Following this, we administered 1 ml of methylene blue through the catheters, and then performed anatomical dissections to accurately identify the location of the catheter tips and compare them to their placement prior to the 'physiotherapy'.

RESULT

CT imaging confirmed the location of the catheter tips at the suprascapular notch in all cases. However, following physiotherapy, 2 catheters (25%) were found to have migrated - specifically, 1 was located in the supraspinatus muscle, and the other was located in the trapezius muscle.

CONCLUSION

Our findings suggest that catheter dislodgement may occur in approximately 25% of cases following simulated physiotherapy manipulation. However, further research is needed to determine the read incidence of catheter dislodgement in clinical practice.

Proposal for Manual Osteopathic Treatment of the Phrenic Nerve

The article reviews the anatomical path of the phrenic nerve and its anastomoses, with the most up-to-date knowledge reported in the literature. We have briefly reviewed the possible phrenic dysfunctions, with the final aim of presenting an osteopathic manual approach for the treatment of the most superficial portion of the nerve, using a gentle technique. The approach we propose is, therefore, a theory based on clinical experience and the rationale that we can extrapolate from the literature. We hope that the article will be a stimulus for further experimental investigations using the technique illustrated in the article. To the authors' knowledge, this is the first article that takes into consideration the hypothesis of an osteopathic treatment with gentle techniques for the phrenic nerve.

Supercharged End-to-Side Nerve Transfer for Ulnar Neuropathy: Redefining Nomenclature and Recommendations for Standardisation of Surgical Technique Description

Supercharged end-to-side (SETS) nerve transfers have been described as a treatment option for ulnar neuropathy, however, there is inconsistency in the nomenclature used to describe the microsurgical technique. The purpose of this article is to systematically review the available literature on the SETS nerve transfer technique and to provide an overview of the technical variations to facilitate standardisation of surgical method. A literature review was performed through PubMed, MEDLINE, and Ovid databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that reported surgical technique of anterior interosseous nerve (AIN) to ulnar nerve SETS transfer were included. Studies were excluded when not referencing SETS/reverse end-to-side (RETS) nerve transfers, studies referencing nerve transfers other than AIN to motor fascicle bundle of the ulnar nerve (MUN), animal studies, and studies not reporting technique. Of the 168 studies found, 14 articles were included. In five articles, distal visualisation of the MUN in Guyon's canal was specifically cited. In the four studies that commented on donor preparation, sharp neurectomy proximal to the AIN branching point was undertaken. Recipient preparation was commented on in seven of the included studies. Two studies referred to an epineurial window only while five specifically recommended a perineurial window. Coaptation site was specified in four studies and all studies used sutures for coaptation, with four articles stipulating that 9-0 nylon was used. Additionally, fibrin glue was used in conjunction with suture technique in four studies. Consistency in nomenclature used to describe SETS microsurgical technique is needed before case series measuring outcome can be reliably interpreted. This review allowed for the development of suggestions for standardisation of nomenclature and minimal reporting requirements when describing SETS technique. Standardisation of technique will allow for reproducibility and facilitate future evaluations of outcome in prospective randomised control trials.

Accuracy of injection pressure measurement at peripheral nerves using high-resolution 40 MHz ultrasound in an anesthetized porcine model

BACKGROUND

Fluid injection pressure measurement is promoted as a marker of needle tip position that discriminates between tissue layers. However, clinical ultrasound has insufficient resolution to identify the exact position of the needle tip. Our primary objective was to use 40 MHz ultrasound in anesthetized pigs in order to precisely locate the tip of the needle and measure opening injection pressure in muscle, at epineurium and in subepineurium.

METHODS

We surgically exposed the axillae of four anesthetized pigs. Two operators placed a 40 MHz ultrasound transducer over the pectoral muscle and imaged axillary, median and radial nerves. Injections (0.5 mL) were randomized to in-plane and out-of-plane needle trajectories and flow rates of 1, 6 and 12 mL/min.

RESULTS

We identified 541 fascicles in 23 nerves. The ratio of fascicle area to nerve area remained constant at ~0.30 for all nerves. Axillary nerves were smaller than median and radial nerves, difference in diameter (95% CI) 1.61 (0.87 to 2.36) mm, p<0.001 and 1.59 (0.82 to 2.36) mm, p=0.001, respectively. Axillary nerves had less fascicles per nerve than median nerves, difference 7.63 (2.43 to 12.83) and radial nerves, difference 9.02 (3.64 to 14.40). We visualized the circumneurium and injection within the subcircumneural compartment. Intraneural injection increased nerve area (SD) from 5.7 (2.2) mm2 to 13.7 (5.5) mm2, difference 8.0 (5.4-10.6) mm2, p<0.001. Mean injection pressure was greater in subepineurium compared with muscle, geometric ratio 2.29 (1.30 to 4.10), p<0.001; and greater on epineurium compared with muscle, geometric ratio 1.73 (1.03 to 3.00), p=0.01. Twenty-two out of 23 injections in muscle, 14 out of 23 injections at epineurium and 11 out of 22 injections in subepineurium were <138 kPa (20 psi).

CONCLUSION

Needle tip position was not discernible using pressure monitoring. The circumneurium and subcircumneural injection compartment were observed but not intrafascicular injection.

An Extremely Rare Case of a Sciatic Nerve Variant

The sciatic nerve (SN) is the nerve of the posterior compartment of the thigh and typically traverses beneath the piriformis muscle (PM) before continuing along a vertical course deep to the gluteus maximus and biceps femoris. However, cadaveric studies have often revealed significant variations in the structural features of the SN in relation to the piriformis. Knowledge of such variations is not only useful for clinicians treating pathophysiologies such as piriformis syndrome and sciatica but is also essential for surgeons carrying out procedures involving the hip and sacroiliac joints to avoid iatrogenic injury to the SN. During routine cadaveric dissection, one such anatomical variant was identified with the SN passing over the superior border of the piriformis muscle. To our knowledge, such a variant is exceedingly rare.

Quantitative assessment of ultrasound-guided sciatic nerve block - A comparison of a single-point versus two-point injection technique: A randomised controlled, double-blinded trial

Background and Aims

Sciatic nerve block at the popliteal level for lower limb procedures provides unpredictable success rates even with ultrasonographic (USG) guidance. This study aimed to compare USG-guided single-point versus two-point injection techniques.

Methods

Sixty patients posted for foot surgeries under USG-guided sciatic nerve block were randomised into Group Single Point, receiving a single injection of 20 mL of 1.5% lignocaine with adrenaline just proximal to the sciatic nerve bifurcation, and Group Double Point, receiving two injections of 10 mL of 1.5% lignocaine with adrenaline, one at the point similar to the first group and a second injection 6 cm above the first point. Sensory blockade onset, time to complete sensory blockade, time to complete motor blockade, length of the nerve exposed and analgesia duration were evaluated. Statistical analysis was performed with Statistical Package for the Social Sciences (SPSS) statistics version 20 software.

Results

Double-point injection technique showed a significantly faster time to complete motor blockade [14.46 (9.93) min], increased length of nerve exposed to local anaesthetic [23.23 (7.209) cm] and extended duration of analgesia [420.40 (99.34) min] compared to the single-point injection technique [20.89 (12.62) min, 18.78 (5.95) cm and 344.28 (125.97) min, respectively]. The onset of sensory blockade and the time to complete sensory blockade were comparable between the two groups.

Conclusion

USG-guided popliteal sciatic nerve block with a double-point injection technique does not significantly shorten the time to complete the sensory block. However, the time to complete motor nerve block and duration of analgesia are prolonged significantly, which may be clinically beneficial for postoperative analgesia.

[Post-traumatic pain mononeuropathies]

Neuropathic pain syndrome (NPS) caused by peripheral nerve (PN) injury is a serious clinical problem due to its prevalence, complexity of pathogenesis, significant impact on the quality of life of patients. The issues of epidemiology, pathogenesis and treatment of patients with NBS with PN injury are considered. Modern possibilities of invasive treatment of such patients are discussed.

Pathological Analysis of Encased Resected Recurrent Nerves in Locally Invasive Thyroid Cancer

Simple Summary

Thyroid cancer encasing the recurrent nerve is rare, and the decision to resect or preserve the nerve is multifactorial. The aim of this retrospective study was to evaluate the rate of actual invasion of the nerve beyond the nerve sheath in cancers encasing the nerve. Fifty-two patients were included: 7 cases of medullary thyroid carcinoma, 8 papillary thyroid carcinomas in children and 37 follicular derived cancers in adults. Tumor-related vocal fold paralysis was present in 30% of cases. The nerve was invaded in 82% of follicular cell-derived tumors, 88% of pediatric cases, and 100% of medullary carcinomas. Only agressive histology was a risk factor for nerve invasion. Vocal fold paralysis was not predictive. To our knowledge, this is one of the largest series with pathologic analysis of resected recurrent nerves, showing a high rate of nerve invasion in these rare cases of cancer encasing the reucrrent nerve.

Abstract

Objective: Thyroid cancer encasing the recurrent nerve is rare, and the decision to resect or preserve the nerve is multifactorial. The objective of this study was to histopathologically analyze resected encased nerves to assess the rate of nerve invasion and risk factors. Materials and Methods: A retrospective study was carried out on consecutive patients with resection of the recurrent nerve for primary or recurrent follicular cell-derived or medullary thyroid carcinoma from 2005 to 2020. Demographics, pathology, locoregional invasion, metastases, recurrences and survival were analyzed. Slides were reviewed blindly by two specialized pathologists (AAG, RC) for diagnosis of invasion deep to the epineurium. Results: Fifty-two patients were included: 25 females; average age, 55 (range 8–87). In total, 87% percent (45/52) were follicular cell-derived with 17/45 (37.8%) aggressive variants; 13% (7/52) were medullary carcinoma. Preoperative vocal fold (VF) paralysis was present in 16/52 (30.7%). Pathologically, the nerve was invaded in 44/52 cases (85%): 82% of follicular cell-derived tumors (37/45), 88% of pediatric cases, and 100% of medullary carcinomas (7/7). Nerve invasion was observed in 11/16 (69%) with preoperative VF paralysis and 33/36 (92%) with normal VF function. Only aggressive histology was correlated with nerve invasion in follicular cell-derived tumors (p = 0.019). Conclusions: The encased nerves were pathologically invaded in 82% of follicular cell-derived tumors and in 100% of medullary carcinomas. Nerve invasion was statistically correlated with aggressive histopathological subtypes and was observed in the absence of VF paralysis in 92% of cases.

Fascial Nomenclature: Update 2022

The connective tissue or fascia plays key roles in maintaining bodily function and health. The fascia is made up of solid and fluid portions, which interpenetrate and interact with each other, forming a polymorphic three-dimensional network. In the vast panorama of literature there is no univocal thought on the nomenclature and terminology that best represents the concept of fascia. The Foundation of Osteopathic Research and Clinical Endorsement (FORCE) organization brings together various scientific figures in a multidisciplinary perspective. FORCE tries to find a common nomenclature that can be shared, starting from the scientific notions currently available. Knowledge of the fascial continuum should always be at the service of the clinician and never become an exclusive for the presence of copyright, or commodified for the gain of a few. FORCE is a non-profit organization serving all professionals who deal with patient health. The article reviews the concepts of fascia, including some science subjects rarely considered, to gain an understanding of the broader fascial topic, and proposing new concepts, such as the holographic fascia.

Effects of double vs triple injection on block dynamics for ultrasound-guided intertruncal approach to the supraclavicular brachial plexus block in patients undergoing upper limb arteriovenous access surgery: study protocol for a double-blinded, randomized controlled trial

Background

Ultrasound-guided intertruncal approach (IA) has been proposed to be an alternative and promising approach to the supraclavicular block (SCB), in which double injection (DI) of local anesthetics (LA) is sequentially administered between intertruncal planes. We would like to apply a refined injection technique, named triple injection (TI) technique, based on the 3 separate compartments visualized by ultrasound. The aim of this study is to compare the percentage of patients with complete sensory blockade at 20 min of DI vs TI technique, when they are applied in patients undergoing upper limb arteriovenous access surgery.

Methods

This study is a prospective parallel-group randomized controlled trial. A total of 86 end-stage renal disease patients will be randomly allocated to receive IA-SCB using either DI or TI technique with identical LA (0.5% ropivacaine 24 mL). The primary outcome is the percentage of patients with complete sensory blockade of all 4 terminal nerves (median, ulnar, radial, and musculocutaneous nerves) of the brachial plexus measured at 20 min after injection. The secondary outcomes will consist of the sensory or motor blockade of all individual nerves, onset times, performance time, diaphragmatic paralysis, surgical anesthesia, and adverse events.

Discussion

It is expected that ultrasound-guided IA-SCB with the TI technique results in better block dynamic in patients undergoing upper limb arteriovenous access surgery.

Trial registration

Chinese Clinical Trial Registry ChiCTR2100045075.

Microscopy of Structures Surrounding Typical Acupoints Used in Clinical Practice and Electron Microscopic Evaluation of Acupuncture Needles

Background and objectives Although the general functionality and structures of acupoints have been studied, there has been little insight into their underlying morphology and physical characteristics. We describe the microanatomical structures surrounding acupoints, the electron microscopic appearance of the needles, and the physical effects of acupuncture needling on the fascia. We injected heparinized blood solution through thin needles at seven known and commonly used "sweat acupoints" in eight fresh, unembalmed, cryopreserved human cadavers to mark the needle positions, and later, during histological examination, to identify them. After the solution was injected, samples were dissected and prepared for histological examination. We examined 350 cross-sections of five different paraffin wax sections from each acupoint microscopically. Acupuncture needles were photographed and superimposed on the cross-sectioned tissues at similar magnifications. Needles were also examined under a scanning electron microscope to judge the roughness or smoothness of their surfaces. A greater conglomeration of nerve endings surrounded the acupoints than in tissues more than 1-3 cm distant from them. Nerve endings and blood vessels were in close contact with a complex network of membranes formed by interlacing collagen fibers, and were always enclosed within those collagen membranes. Nerve endings were found within hypodermis, muscles, or both. Scanning electron microscopy demonstrated the three-dimensional shapes and sizes of the needles, and the degree of roughness or smoothness of their polished external surfaces. We demonstrate a delicate arrangement of nerve endings and blood vessels enclosed within complex collagen membrane networks at acupoints within the hypodermis and muscle. This arrangement could explain why needling is an essential step in the acupuncture process that provides favorable outcomes in clinical practice.

Sciatic nerve movement in the deep gluteal space during hip rotations maneuvers

We hypothesize that the sciatic nerve in the subgluteal space has a specific behavior during internal and external coxofemoral rotation and during isometric contraction of the internal and external rotator muscles of the hip. In 58 healthy volunteers, sciatic nerve behavior was studied by ultrasound during passive internal and external hip rotation movements and during isometric contraction of internal and external rotators. Using MATLAB software, changes in nerve curvature at the beginning and end of each exercise were evaluated for longitudinal catches and axial movement for transverse catches. In the long axis, it was observed that during the passive internal rotation and during the isometric contraction of external rotators, the shape of the curve increased significantly while during the passive external rotation and the isometric contraction of the internal rotators the curvature flattened out. During passive movements in internal rotation, on the short axis, the nerve tended to move laterally and forward, while during external rotation the tendency of the nerve was to move toward a medial and backward position. During the isometric exercises, this displacement was less in the passive movements. Passive movements of hip rotation and isometric contraction of the muscles affect the sciatic nerve in the subgluteal space. Retrotrochanteric pain may be related to both the shear effect of the subgluteus muscles and the endoneural and mechanosensitive aggression to which the sciatic nerve is subjected.

High-definition ultrasound imaging defines the paraneural sheath and fascial compartments surrounding the cords of the brachial plexus at the costoclavicular space and lateral infraclavicular fossa

BACKGROUND AND OBJECTIVES

The paraneural sheath is a multilayered network of collagen fibers that surround the brachial plexus. Currently, there are no sonographic data on the paraneural sheath of the brachial plexus, which this study aimed to evaluate.

METHODS

Ultrasound imaging datasets of 100 patients who received a costoclavicular brachial plexus block, using high-definition ultrasound imaging, were retrospectively reviewed. Video files, representing sonograms before and after the local anesthetic injection, from the costoclavicular space and lateral infraclavicular fossa were collated and reviewed by three experienced anesthesiologists. Frequency (yes/no) of ultrasound visualization of the paraneural sheath, septum, and the anterior and posterior compartments was assessed. Representative sonograms from the costoclavicular space and lateral infraclavicular fossa were visually correlated with archived cadaver microanatomic sections from the same location.

RESULTS

Datasets of the 98 patients who achieved surgical anesthesia were evaluated. The paraneural sheath, septum, and the anterior and posterior compartments were visualized in 17.3%, 7.1%, 5.1% and 5.1%, respectively, at the costoclavicular space before the brachial plexus block; this contrasts (p<0.001) with their visibility post-block (94.9%, 75.5%, 75.5% and 75.5%, respectively). At the lateral infraclavicular fossa, the corresponding visibility of these structures post-block were 67.7%, 81.5%, 81.5% and 81.5%, respectively. Ultrasound images of the paraneural sheath and septum correlated well with that in the cadaver microanatomic sections.

CONCLUSION

We have demonstrated the paraneural sheath and fascial compartments surrounding the cords of the brachial plexus at the costoclavicular space and lateral infraclavicular fossa using high-definition ultrasound imaging.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04370184), (https://www.clinicaltrials.gov/).

Topography and evidence of a separate "fascia plate" for the femoral nerve inside the iliopsoas - A dorsal approach

The femoral nerve stretch test is an essential part of clinical neurological examinations. This test is performed alongside Magnetic Resonance Imaging (MRI) to determine if there is any evidence of nerve root irritation, usually as a consequence of disc prolapse. The test occasionally gives false positive results. Why such false positives can occur, is subject to continued research, however, no obvious reason has yet emerged. We hypothesize that connectives of the femoral nerve may explain such a phenomenon. To see these connectives, we approached the femoral nerve from dorsal in 12 cases. With the use of ink injection into the subparaneural compartment of the femoral nerve and dissections, a thin transparent structure can clearly be seen that is separate from the epineurium, perineurium, and a paraneural sheath. A continuation of the paraneural sheath produces a fascia plate approximately 1.5 cm in width and with a thickness of around 3 mm, which not only circumnavigates the nerve but projects into the surrounding tissues. Our qualitative observations show that not only does this femoral nerve fascia plate exists, but it also contains nerves and vessels. Furthermore, we show that the femoral nerve is connected to the myofascial complex of the iliopsoas, and in a separate fascia plate from the iliopsoas fascia. This plate is a hitherto neglected connective which extends as far as the spinal dura mater. Evidence from our plastinates and histological sections suggests that when tension is applied to the femoral nerve during the femoral nerve stretch test, tension is also applied to the femoral nerve fascia plate. The femoral nerve fascia plate could be a specific factor that contributes to pain resulting in a false positive femoral nerve stretch test.

Ultrasound-guided subparaneural popliteal sciatic nerve block: there is more to it than meets the eyes

The popliteal sciatic nerve block is routinely used for anesthesia and analgesia during foot and ankle surgery. This article reviews our current understanding of the anatomy of the sciatic nerve and discusses how fascial tissue layers associated with the nerve may affect block outcomes . The anatomy of the sciatic nerve is more complex than previously described. The tibial and common peroneal nerves within the sciatic nerve trunk appear to be centrally separated by the Compton-Cruveilhier septum and encompassed by their own paraneural sheaths. This unique internal architecture of the sciatic nerve appears to promote proximal spread of local anesthetic to the internal aspect of the sciatic nerve trunk after a subparaneural injection at or below the divergence of the tibial and common peroneal nerves.

The Five Diaphragms in Osteopathic Manipulative Medicine: Neurological Relationships, Part 2

The main objective of the osteopath and that of osteopathic manipulative medicine (OMM) is to create space between the different tissues. The sliding capacity of the various tissue layers and between the different body components, up to the possibility of movement between cells is the salutogenic stimulus to allow the circulation of fluids, the biochemical exchange, and the adequate management of the multiple internal and external stimuli that perturb the body living. Movement is allowed by space and space is life. In this second part, the exposure of the anatomical neurological relationships of the five diaphragms continues, highlighting the relationships of the thoracic outlet, the respiratory diaphragm, and the pelvic floor. Finally, there will be clinical reflections to further corroborate the existence of the anatomical continuum and to lay the scientific foundations for an OMM approach to body diaphragms.

Comparison of the effectiveness of circumferential versus non-circumferential spread in median and ulnar nerve blocks. A double-blind randomized clinical trial

BACKGROUND AND OBJECTIVES

Circumferential (C) spread of local anesthetic around the nerve is recommended for a successful nerve block. We tested the hypothesis that C spread produces a more complete block than non-circumferential (NC) spread.

METHODS

We randomized 124 patients undergoing open carpal tunnel syndrome surgery to receive C or NC spread ultrasound-guided median and ulnar nerve blocks. The primary outcome was the proportion of patients who developed complete sensory block measured at 5, 15 and 30 min. The loss of cold sensation was graded as: 0 (complete block), 1 (incomplete block), or 2 (no block). Secondary outcomes included motor block, nerve swelling and adverse events.

RESULTS

In group C, complete sensory block at 5 min was 2.4 (95% CI 1.0 to 5.7; p=0.04) times more frequent in the median nerve and 3.0 (95% CI 1.2 to 7.2; p=0.01) times more frequent in the ulnar nerve compared with group C. However, at 15 and 30 min, it was similar between groups. Complete motor block was more frequent in group C than in group NC for both the median nerve: 1.5 (95% CI 1.1 to 2.2; p<0.01) at 15 min, 1.1 (95% CI 1.0 to 1.2; p=0.02) at 30 min, and the ulnar nerve: 1.7 (95% CI 1.2 to 2.6; p<0.01) at 15 min, 1.2 (95% CI 1.0 to 1.4; p<0.01) at 30 min. The incidence of nerve swelling and adverse effects was similar between groups.

CONCLUSIONS

C spread around the median and ulnar nerves at the level of the antecubital fossa generates more complete sensory and motor blocks compared with NC spread.

TRIAL REGISTRATION NUMBER

EudraCT 2011-002608-34 and NCT01603680.