Nerve and Arterial Supply Pattern of the Popliteus Muscle and Clinical Implications.

INTRODUCTION: The aim of this study was to investigate the nerve and artery supply and the tibial attachment of the popliteus muscle using anatomical methods. METHODS: Forty-four nonembalmed and embalmed extremities were dissected for this study. To measure the attachment area of the popliteus, the most prominent points of the medial epicondyle of the femur and the medial malleolus of the tibia were identified before dissection. A line connecting these two prominent points was used as the reference line, with the most prominent point of the medial epicondyle of the femur as the starting point. This study also investigated the area where the popliteus attaches to the bone and the points where nerves and arteries enter the popliteus muscle when it is divided into three equal parts in the coronal plane. RESULTS: The mean length of the reference line was 34.6 ± 2.1 cm. The origin of the popliteus was found to be at a distance of 16.6% to 35.2% on the tibial bone from the proximal region. The popliteus was innervated by only the tibial nerve in 90% of the cases and by the tibial and the sciatic nerves in the remaining 10% of the cases. The inferior medial genicular artery and the posterior tibial artery supplied blood to the popliteus in 90% and 65% of the cases, respectively. When the popliteus muscle was divided into three equal parts in the coronal plane, the nerve and the artery were found to enter the muscle belly in zones II and III and zones I and II in 92% and 98% of the specimens, respectively. Discussion. The anatomical investigation of the popliteus in this study will help identify patients with clinically relevant syndromes.

Effect of melatonin on peripheral nerve damage resulting from tibial defect in rats / Efecto de la melatonina sobre el daño de los nervios periféricos como resultado de un defecto tibial en ratas

SUMMARY: Peripheral nerve damage (PNI) can cause demyelination, axonal degeneration and loss of motor and sensory function. Melatonin with its antioxidative effect, has been reported to reduce scar formation in nerve injury, take a role in repair process by suppressing fibroblast proliferation in the damaged area. It was aimed to investigate the effect of melatonin in the repair of peripheral nerve damage and the relationship between S100 proteins and angiogenic regulation. Wistar albino rats were divided into 3 groups. In the Defect group, 6 mm tibial bone defect using a motorized drill was created and kept immobile for 28 days. In Defect + graft group, tibial bone defect with allograft treatment was applied and kept immobile for 28 days. In Defect + graft + Melatonin group, melatonin was administered to defect + allograft group. All rats were sacrified by decapitation, skin and tibia bone were removed then fixed with 10 % neutral buffered formalin and embedded in paraffin, sections were examined under light microscopy. In the Defect+Graft group, enlargement and occlusion of the vessels with degeneration of the epineural sheath, thickening of the endoneural sheath and mild hyperplasia of schwannocytus (Schwann cells) were remarkable. In the Defect+Graft+Melatonin group, the epineural sheath was tight and regular, the axonal structures were prominent in the endoneural area. Mild S100 expression was observed in Defect+Graft group in fibers of the endoneural region with a prominent expression in schwannocytus. In Defect+Graft+Melatonin group (10mg/kg), S100 expression was moderate in areas where schwannocytus proliferated and nerve-connective tissue sheaths were reconstructed. VEGF expression was moderate in endoneural, perineural and epineural connective tissue sheaths in the Defect+Graft+Melatonin group, with negative expression in blood vessel endothelial cells, but with a positive expression in schwannocytus. We conclude that with the application of melatonin; oxidative stress decreases, schwannocytus proliferation increases, having positive influence on nerve repair with the regulation of S100 signaling and angiogenetic structuring.

RESUMEN: El daño a los nervios periféricos puede causar desmielinización, degeneración axonal y pérdida de la función motora y sensorial. Se ha informado que la melatonina, con su efecto antioxidante, reduce la formación de cicatrices en lesiones nerviosas y desempeña un papel en el proceso de reparación al suprimir la proliferación de fibroblastos en el área dañada. El objetivo de este trabajo fue investigar el efecto de la melatonina en la reparación del daño de los nervios periféricos y la relación entre las proteínas S100 y la regulación angiogénica. Ratas albinas Wistar se dividieron en 3 grupos. En el grupo Defecto, se creó un defecto óseo tibial de 6 mm con un taladro motorizado y se mantuvo inmóvil durante 28 días. En el grupo Defecto + injerto, se aplicó tratamiento de defecto óseo tibial con aloinjerto y se mantuvo inmóvil durante 28 días. En el grupo Defecto + injerto + Melatonina, se administró melatonina al grupo defecto + aloinjerto. Todas las ratas fueron sacrificadas por decapitación, se extrajo la piel y el hueso de la tibia y luego se fijaron con formalina tamponada neutra al 10 % y se incluyeron en parafina, las secciones se examinaron bajo microscopía óptica. En el grupo Defecto+Injerto, fueron notables el agrandamiento y la oclusión de los vasos con degeneración de la vaina epineural, engrosamiento de la vaina endoneural e hiperplasia leve de los schwannocitos (neurolemnocitos). En el grupo Defecto+Injerto+Melatonina, la vaina epineural era estrecha y regular, las estructuras axonales eran prominentes en el área endoneural. Se observó expresión leve de S100 en el grupo Defecto+Injerto en fibras de la región endoneural con una expresión prominente en los schwannocitos. En el grupo Defecto+Injerto+Melatonina, la expresión de S100 fue moderada en áreas donde proliferaron los schwannocitos y se reconstruyeron las vainas de tejido conectivo nervioso. La expresión de VEGF fue moderada en vainas de tejido conectivo endoneural, perineural y epineural en el grupo Defecto+Injerto+Melatonina, con expresión negativa en células endoteliales de vasos sanguíneos, pero con expresión positiva en schwannocitos. Concluimos que con la aplicación de melatonina; disminuye el estrés oxidativo, aumenta la proliferación de schwannocitos, influyendo positivamente en la reparación nerviosa con la regulación de la señalización S100 y la estructuración angiogenética.

Tocotrienol-Rich Vitamin E (Tocovid) Improved Nerve Conduction Velocity in Type 2 Diabetes Mellitus Patients in a Phase II Double-Blind, Randomized Controlled Clinical Trial.

Diabetic peripheral neuropathy (DPN) is the most common microvascular complication of diabetes that affects approximately half of the diabetic population. Up to 53% of DPN patients experience neuropathic pain, which leads to a reduction in the quality of life and work productivity. Tocotrienols have been shown to possess antioxidant, anti-inflammatory, and neuroprotective properties in preclinical and clinical studies. This study aimed to investigate the effects of tocotrienol-rich vitamin E (Tocovid SuprabioTM) on nerve conduction parameters and serum biomarkers among patients with type 2 diabetes mellitus (T2DM). A total of 88 patients were randomized to receive 200 mg of Tocovid twice daily, or a matching placebo for 12 months. Fasting blood samples were collected for measurements of HbA1c, renal profile, lipid profile, and biomarkers. A nerve conduction study (NCS) was performed on all patients at baseline and subsequently at 2, 6, 12 months. Patients were reassessed after 6 months of washout. After 12 months of supplementation, patients in the Tocovid group exhibited highly significant improvements in conduction velocity (CV) of both median and sural sensory nerves as compared to those in the placebo group. The between-intervention-group differences (treatment effects) in CV were 1.60 m/s (95% CI: 0.70, 2.40) for the median nerve and 2.10 m/s (95% CI: 1.50, 2.90) for the sural nerve. A significant difference in peak velocity (PV) was also observed in the sural nerve (2.10 m/s; 95% CI: 1.00, 3.20) after 12 months. Significant improvements in CV were only observed up to 6 months in the tibial motor nerve, 1.30 m/s (95% CI: 0.60, 2.20). There were no significant changes in serum biomarkers, transforming growth factor beta-1 (TGFß-1), or vascular endothelial growth factor A (VEGF-A). After 6 months of washout, there were no significant differences from baseline between groups in nerve conduction parameters of all three nerves. Tocovid at 400 mg/day significantly improve tibial motor nerve CV up to 6 months, but median and sural sensory nerve CV in up to 12 months of supplementation. All improvements diminished after 6 months of washout.

Smad2 and Smad3 expressed in skeletal muscle promote immobilization-induced bone atrophy in mice.

Skeletal muscle is known to regulate bone homeostasis through muscle-bone interaction, although factors that control this activity remain unclear. Here, we newly established Smad3-flox mice, and then generated skeletal muscle-specific Smad2/Smad3 double conditional knockout mice (DcKO) by crossing Smad3-flox with skeletal muscle-specific Ckmm Cre and Smad2-flox mice. We show that immobilization-induced gastrocnemius muscle atrophy occurring due to sciatic nerve denervation was partially but significantly inhibited in DcKO mice, suggesting that skeletal muscle cell-intrinsic Smad2/3 is required for immobilization-induced muscle atrophy. Also, tibial bone atrophy seen after sciatic nerve denervation was partially but significantly inhibited in DcKO mice. Bone formation rate in wild-type mouse tibia was significantly inhibited by immobilization, but inhibition was abrogated in DcKO mice. We propose that skeletal muscle regulates immobilization-induced bone atrophy via Smad2/3, and Smad2/3 represent potential therapeutic targets to prevent both immobilization-induced bone and muscle atrophy.

Effectiveness of transcutaneous tibial nerve stimulation at two different thresholds for overactive bladder symptoms in older women: a randomized controlled clinical trial.

OBJECTIVES: To compare the effectiveness of transcutaneous tibial nerve stimulation (TTNS) at two different current amplitude thresholds (sensory and motor) in terms of urinary habit, symptoms and the degree of discomfort of overactive bladder (OAB) in older women. STUDY DESIGN: This is a randomized, controlled, 3-arm blinded trial. One hundred and one patients attending secondary care with OAB were randomized into one of three groups: group 1, TTNS sensitivity threshold (n = 39); group 2, TTNS motor threshold (n = 33); and control group 3 (n = 29). MAIN OUTCOME MEASURES: Participants allocated to groups 1 and 2 had 8 sessions of TTNS for 30 min, twice a week. Group 3 received no intervention. The results measured were the symptoms of overactive bladder (ICIQ-OAB, overall score), bother scales (to indicate the impact of individual symptoms for the patient) and urinary habit (3-day bladder diary). A blind assessor measured outcomes at baseline and 5 weeks after randomization. RESULTS: After five weeks, a statistically significant difference between group 3 (control) and group 1 (TTNS sensitivity threshold) and group 2 (TTNS motor threshold) was observed in the intergroup analysis, but no difference in the outcomes analyzed was detected between the two groups receiving intervention (groups 1 and 2). CONCLUSION: TTNS is effective in the treatment of OAB in older women, with no difference between the sensitivity and motor thresholds. CLINICAL TRIAL REGISTRATION NUMBER: Registro Brasileiros de Ensaios Clínicos (RBR-39DZ5V).

Sensory nerves protect from the progression of early stage osteoarthritis in mice.

PURPOSE: Osteoarthritis (OA) is a chronic degenerative joint disease. Sensory nerves play an important role in bone metabolism and in the progression of inflammation. This study explored the effects of sensory nerve on OA progression at early stage in mice. MATERIALS AND METHODS: OA was induced via destabilization of the medial meniscus (DMM) in C57BL/6 mice. Sensory denervation was induced by subcutaneous injection of capsaicin (90 mg/kg) one week prior to DMM. One week after capsaicin injection, sensory denervation in the tibia was confirmed by immunofluorescent staining. Four weeks after DMM, micro-CT scans, histological analysis, and RT-PCR tests were performed to evaluate OA progression. RESULTS: Subcutaneous injection of capsaicin successfully induced sensory denervation in tibia. The Osteoarthritis Research Society International (OARSI) score and synovitis score of the capsaicin+DMM group were significantly higher than the score of the vehicle+DMM group. The BV/TV of the tibial subchondral bone in the capsaicin+DMM group was significantly lower than in the vehicle+DMM group. In addition, the level of expression of inflammatory factors in the capsaicin+DMM group was significantly higher than in the vehicle+DMM group. CONCLUSIONS: Capsaicin-induced sensory denervation accelerated OA progression at early stage in mice. To put it another way, sensory nerve protects from OA progression at early stage in mice.

Investigation of genicular neurotomy of the knee: MRI characterization of anatomy and implications for intervention.

BACKGROUND: Genicular nerve block and subsequent radiofrequency neurotomy (RFN) has emerged as a novel intervention and alternative for total knee arthroplasty in patients with refractory pain from knee osteoarthritis (OA). To our knowledge, there is no cited report correlating the accuracy of localizing the genicular nerves using bony landmarks on magnetic resonance imaging (MRI). OBJECTIVES: To quantify the proximity of superomedial genicular nerve (SMGN), superolateral genicular nerve (SLGN), and inferomedial genicular nerve (IMGN) from a target point. The target point was an intersection marked by a line parallel to the diaphysis and a separate line parallel to the metaphyseal flare along the cortical surfaces of both the femur and tibia. DESIGN: Retrospective chart review. PATIENTS: A total of 25 de-identified knee MRIs were reviewed. METHODS: The coronal proton density fat suppressed sequence was used for identification and localization of the SLGN, SMGN, and IMGN. The neurovascular bundles were traced from posterior location along their origin as they wrap around the distal diaphysis. The nerve locations were determined by consensus measurements performed by two board-certified radiologists with certificates of added qualification in neuroradiology and interventional radiology. The proximity of each respective genicular nerves was measured by drawing a perpendicular line from each genicular nerve to the height of the target point. All measurements were taken on the mid-coronal view at the point of maximal epiphyseal flare. MAIN OUTCOME MEASUREMENTS: Positive values indicated the location of the neurovascular bundle to be superior to the target point. Negative values indicated the location of the neurovascular bundle to be inferior to the target point. RESULTS: The distance between our target point and the inferior border of SLGN ranged from -3 mm to 6 mm. Twenty-three out of 25 (92%) SLGN lied exactly at or above our target intersection. The distance between our target point and the inferior border of SMGN ranged from -1 mm to 2 mm with twenty-two out of 25 (88%) SMGN lied exactly at or above our target point. The distance between our target point and the superior border of IMGN ranged from 0 mm to 3 mm with all (100%) IMGN lying exactly at or above the target point. CONCLUSION: The intersection of the femoral diaphyseal shaft to a line along the metaphyseal flare and the intersection of the tibial diaphyseal shaft to a line along the medial metaphyseal can be used as a target point to localize the genicular nerves with close proximity.

Sciatic Nerve Variants in Patients Diagnosed With Sciatica: Is There a Correlation?

PURPOSE: Compression of the sciatic nerve in its path along the piriformis muscle can produce sciatica-like symptoms. There are 6 predominant types of sciatic nerve variations with type 1 being the most common (84.2%), followed by type 2 (13.9%). However, there is scarce literature on the prevalence of sciatic nerve variation in those diagnosed with sciatica. MATERIALS AND METHODS: The charts of 95 patients clinically diagnosed with sciatica who had a magnetic resonance imaging of the pelvis/hip were retrospectively studied. All patients had T1-weighted axial, coronal, and sagittal images. Magnetic resonance imagings were interpreted separately by 2 board-certified fellowship-trained musculoskeletal radiologists to identify the sciatic nerve variant. RESULTS: Seven cases were excluded because of inadequate imaging. Of the remaining 88 patients, 5 had bilateral sciatica resulting in a sample size of 93 limbs. Fifty-two (55.9%) had type 1 sciatic nerve anatomy, 39 (41.9%) had type 2, and 2 (2.2%) had type 3. The proportions of type 1 and 2 variations were significantly different from the normal distribution (P < 0.001), whereas type 3, 4, 5, and 6 variants were not (P = 1.00). CONCLUSIONS: There is strong statistical significance regarding the relationship between sciatic nerve variation and the clinical diagnosis of sciatica. Preoperative magnetic resonance imaging can be considered in sciatica patients to prevent iatrogenic injury in pelvic surgery.

Visual inputs and postural manipulations affect the location of somatosensory percepts elicited by electrical stimulation.

The perception of somatosensation requires the integration of multimodal information, yet the effects of vision and posture on somatosensory percepts elicited by neural stimulation are not well established. In this study, we applied electrical stimulation directly to the residual nerves of trans-tibial amputees to elicit sensations referred to their missing feet. We evaluated the influence of congruent and incongruent visual inputs and postural manipulations on the perceived size and location of stimulation-evoked somatosensory percepts. We found that although standing upright may cause percept size to change, congruent visual inputs and/or body posture resulted in better localization. We also observed visual capture: the location of a somatosensory percept shifted toward a visual input when vision was incongruent with stimulation-induced sensation. Visual capture did not occur when an adopted posture was incongruent with somatosensation. Our results suggest that internal model predictions based on postural manipulations reinforce perceived sensations, but do not alter them. These characterizations of multisensory integration are important for the development of somatosensory-enabled prostheses because current neural stimulation paradigms cannot replicate the afferent signals of natural tactile stimuli. Nevertheless, multisensory inputs can improve perceptual precision and highlight regions of the foot important for balance and locomotion.

Study of the mechanisms of action of the hypoalgesic effect of pressure under shock waves application: A randomised controlled trial.

OBJECTIVE: To determine if the perceived pain intensity during the application of shock waves (SWs) is a determinant mechanism in producing hypoalgesic changes in pressure pain thresholds (PPTs) in asymptomatic individuals. DESIGN: A randomised, single-blind controlled trial [NCT03455933]. SETTING: University. PARTICIPANTS: Sixty-three asymptomatic individuals. INTERVENTIONS: Participants were randomised into three groups: 1-SWs causing mild pain (SW-DP); 2-SWs generating moderate pain (SW-MP); and 3-cold pressor test (CPT). MAIN OUTCOME MEASUREMENTS: Before and after the intervention, the PPT was evaluated bilaterally at the following points: lateral epicondyle, median nerve in the flexure of the elbow, and tibia. RESULTS: The results showed differences between various groups over time for all PPTs assessments, due to the existence of statistically significant differences in the interaction group x times (dominant arm lateral epicondyle [P < 0.001; η2p = 0.255]; dominant arm median nerve [P = 0.001; η2p = 0.212]; nondominant arm lateral epicondyle [P < 0.001; η2p = 0.275]; nondominant arm median nerve [P < 0.001; η2p = 0.268]; tibia [P = 0.012, η2p = 0.138]). The SW-MP group obtained a significant increase in all the PPT evaluations compared with the SW-DP group (d > 0.80). The CPT group only showed significantly higher results, and of high magnitude (d > 0.80), regarding the SW-DP group for the PPT evaluation in the dominant member. The SW-MP group showed differences compared with the CPT only for the PPT obtained in the nondominant arm. CONCLUSIONS: The findings show that SW treatment generates a hypoalgesic effect on the application point, with moderate pain. Further studies are necessary in order to link these hypoalgesic changes to the activation of the descending inhibitory systems.

Posterior tibial perforators relationship with superficial nerves and veins: A cadaver study.

BACKGROUND: Most authors have evaluated the location of lower leg arterial perforators, but little is still known about the relationship between the arterial network and great saphenous vein (GSV) and saphenous nerve (SN). The aim of this study is to evaluate the relationship between the arterial network of the posterior tibial artery perforators, the cutaneous nerves, and the superficial venous system in the lower one third of the leg. METHODS: Eighteen lower limbs from cadavers were used for this study. The arterial and venous compartment were selectively injected with a mixture of barium sulfate and epoxy. The specimen were CT scanned and the superficial veins, nerves, and the arterial perforators were dissected. RESULTS: A large perforator of the posterior tibial artery was found at a mean distance of 6.23 cm ± 0.88, with a 95% CI: 5.79-6.67, from the medial malleolus. The average diameter was 0.9 mm ± 0.17, with a 95% CI: 0.81-0.99. In 67% the connection of the venae comitantes to the superficial venous system was established with the GSV, in the other cases, with Leonardo's vein. Both dissection and imaging studies showed perineural interperforator connections along the branches of SN in all the specimens examined. CONCLUSIONS: The distribution pattern of posterior tibial artery perforators followed the superficial nerves in this region. There is an interperforator anastomotic network along the SN. The various patterns of the venous drainage system, in relationship to the distribution of the branches of posterior tibial artery perforators, have been clarified.

Two accessory muscles of leg: potential source of entrapment of posterior tibial vessels.

Accessory muscles can be found in any part of the body. In most of the regions, they go unnoticed. However, in some cases, they become symptomatic or of cosmetic concern. In this particular case, the presence of two accessory muscle slips was observed in the flexor compartment of the leg. Among the two, the first accessory muscle belly connected the lower part of flexor hallucis longus to the tibialis posterior. The muscle crossed superficial to the posterior tibial vessels. The second accessory muscle took origin from the connective tissue around the lower part of the posterior tibial vessels and was inserted to the upper part of the lateral border of tibia near the attachment of the interosseous membrane. One of the accessory muscles crossed the posterior tibial vessels, while the other surrounded them. The above accessory muscles were supplied by the branches of tibial nerve.

Innervation of the tibial epiphysis through the intercondylar foramen.

The periosteum and mineralized bone are innervated by nerves that sense pain. These include both myelinated and unmyelinated neurons with either free nerve endings or bearing nociceptors. Parasympathetic and sympathetic autonomic nerves also innervate bone. However, little is known about the route sensory nerves take leaving the epiphyses of long bones at the adult knee joint. Here, we used transgenic mice that express fluorescent Venus protein in Schwann cells (Sox10-Venus mice) to visualize myelinated and unmyelinated nerves in the tibial epiphysis. Immunofluorescence to detect a pan-neuronal marker and the sensory neuron markers calcitonin gene-related peptide (CGRP) and tropomyosin receptor kinase A (TrkA) also revealed Schwann cell-associated sensory neurons. Foramina in the intercondylar area of the tibia were conserved between rodents and primates. Venus-labeled fibers were detected within bone marrow of the proximal epiphysis, exited through foramina along with blood vessels in the intercondylar area of the tibia, and joined Venus-labeled fibers of the synovial membrane and meniscus. These data suggest that innervation of the subchondral plate and trabecular bone within the tibial epiphysis carries pain signals from the knee joint to the brain through intercondylar foramina.

How many nerve fibres can be separated as donor from an integral nerve trunk when reconstructing a peripheral nerve trauma with amplification method by artificial biochitin conduit?

Using portion of a nearby nerve trunk to reconstruct a severe nerve lesion by artificial biodegradable chitin conduit is the core practicable method based on peripheral nerve amplification regeneration. However, the quantitative influences on skeletal muscle function corresponding to the injury of the donated nerve fibres were not previously reported. Here, we aimed to explore the compensative capacity in tibialis anterior muscles of rats with the models of acute tibialis anterior nerve branch injuries. The tibialis anterior branch of deep peroneal nerve was transected in various levels each time. Both the decreased treads of maximal compound muscle action potential (CMAP) amplitude and complete tetanic tension of the tibialis anterior muscle in rats were similar with the increasing numbers of damaged nerve fibres, which showed two S-shaped curves. When the nerve injury level was less than approximately 10%, the skeletal muscle function remained normal through complete compensation of motor endplates. As the injury degree went from 10% to 85%, the muscle function was partially impaired due to the broken compensation of motor endplates. When the nerve injury level was over approximately 85%, the skeletal muscle function was totally lost. It suggests that within a certain level of nerve injury, the skeletal muscle function maintained basically unchanged via complete compensation of motor endplates. Such nerve fibres may be used as donor nerve to repair peripheral nerve injury.

Cutaneous sensitivity in unilateral trans-tibial amputees.

AIM: To examine tactile sensitivity in the leg and foot sole of below-knee amputees (diabetic n = 3, traumatic n = 1), and healthy control subjects (n = 4), and examine the association between sensation and balance. METHOD: Vibration perception threshold (VPT; 3, 40, 250Hz) and monofilaments (MF) were used to examine vibration and light touch sensitivity on the intact limb, residual limb, and homologous locations on controls. A functional reach test was performed to assess functional balance. RESULTS: Tactile sensitivity was lower for diabetic amputee subjects compared to age matched controls for both VPT and MF; which was expected due to presence of diabetic peripheral neuropathy. In contrast, the traumatic amputee participant showed increased sensitivity for VPT at 40Hz and 250Hz vibration in both the intact and residual limbs compared to controls. Amputees with lower tactile sensitivity had shorter reach distances compared to those with higher sensitivity. CONCLUSION: Changes in tactile sensitivity in the residual limb of trans-tibial amputees may have implications for the interaction between the amputee and the prosthetic device. The decreased skin sensitivity observed in the residual limb of subjects with diabetes is of concern as changes in skin sensitivity may be important in 1) identification/prevention of excessive pressure and 2) for functional stability. Interestingly, we saw increased residual limb skin sensitivity in the individual with the traumatic amputation. Although not measured directly in the present study, this increase in tactile sensitivity may be related to cortical reorganisation, which is known to occur following amputation, and would support similar findings observed in upper limb amputees.

Avoiding Neurovascular Risk During Percutaneous Clamp Reduction of Spiral Tibial Shaft Fractures: An Anatomic Correlation With Computed Tomography.

The use of percutaneous clamps is often a helpful tool to aid reduction and intramedullary nailing of distal tibial spiral diaphyseal fractures. However, the anterior and posterior neurovascular bundles are at risk without careful clamp placement. We describe our preferred technique of percutaneous clamp reduction for distal spiral tibial fractures with a distal posterolateral fracture spike, with care to protect the adjacent neurovascular structures. We also investigated the relationship between these neurovascular structures and the site of common percutaneous clamp placement. Preoperative computed tomography images of surgically managed patients who sustained this specific common fracture pattern (distal third spiral diaphyseal tibia fracture with a posterolateral fragment) were retrospectively reviewed. On computed tomography, we extrapolated the ideal virtual clamp site on the posterolateral fracture fragment to facilitate reduction. The average distance of this clamp position from the anterior neurovascular bundle was 14 mm (SD = 7.6), with a range of 6-32 mm. The average distance of the clamp site from the posterior neurovascular bundle was 19 mm (SD = 6.1), with a range of 11-30 mm. In 31% of patients, the distal fragment's apex extended anterior to the interosseous membrane, and in 69% of patients, the apex was posterior to the interosseous membrane. We also describe our preferred surgical technique with percutaneous clamping and tibial nailing, which involves sliding the posterolateral tine of the percutaneous clamp along the lateral tibial cortex to prevent neurovascular bundle injury.

Anatomical feasibility study of flexor hallucis longus transfer in treatment of Achilles tendon and posteromedial portal of ankle arthroscopy.

PURPOSE: The aim of this study was to evaluate the occurrence of anatomical variations of the musculotendinous junction of the flexor hallucis longus (FHL) muscle, the relationship between FHL tendon or muscle and the tibial neurovascular bundle at the level of the posterior ankle joint in human cadavers. METHODS: Seventy embalmed feet from 20 male and 15 female cadavers, the cadavers' mean age was 65.4 (range from 14 to 82) years, were dissected and anatomically classified to observe FHL muscle morphology define the relationship between FHL tendon or muscle and the tibial neurovascular bundle. The distance between the musculotendinous junction and the relationship between FHL tendon or muscle and the tibial neurovascular bundle was determined. RESULTS: Three morphology types of FHL muscle were identified: a long lateral and shorter medial muscle belly, which was observed in 63 specimens (90%); equal length medial and lateral muscle bellies, this variant was only observed in five specimens (7.1%); one lateral and no medial muscle belly, which was observed in two specimens (2.9%). No statistically significant difference was observed according to gender or side (p > 0.05). Two patterns were identified and described between FHL tendon or muscle and the tibial neurovascular bundle. Pattern 1, the distance between the neurovascular bundle and FHL tendon was 3.46 mm (range 2.34-8.84, SD = 2.12) which was observed in 66 specimens (94.3%); Pattern 2, there was no distance which was observed in four specimens (5.7%). CONCLUSION: Knowing FHL muscle morphology, variations provide new important insights into secure planning and execution of a FHL transfer for Achilles tendon defect as well as for the interpretation of ultrasound and magnetic resonance images. With posterior arthroscopic for the treatment of various ankle pathologies, posteromedial portal may be introduced into the posterior aspect of the ankle without gross injury to the tibial neurovascular structures because of the gap between the neurovascular bundle and FHL tendon.

Optical Read-out of Neural Activity in Mammalian Peripheral Axons: Calcium Signaling at Nodes of Ranvier.

Current neural interface technologies have serious limitations for advanced prosthetic and therapeutic applications due primarily to their lack of specificity in neural communication. An optogenetic approach has the potential to provide single cell/axon resolution in a minimally invasive manner by optical interrogation of light-sensitive reporters and actuators. Given the aim of reading neural activity in the peripheral nervous system, this work has investigated an activity-dependent signaling mechanism in the peripheral nerve. We demonstrate action potential evoked calcium signals in mammalian tibial nerve axons using an in vitro mouse model with a dextran-conjugated fluorescent calcium indicator. Spatial and temporal dynamics of the signal are presented, including characterization of frequency-modulated amplitude. Pharmacological experiments implicate T-type CaV channels and sodium-calcium exchanger (NCX) as predominant mechanisms of calcium influx. This work shows the potential of using calcium-associated optical signals for neural activity read-out in peripheral nerve axons.

Electrical stimulation attenuates morphological alterations and prevents atrophy of the denervated cranial tibial muscle.

OBJECTIVE: To investigate if electrical stimulation through Russian current is able to maintain morphology of the cranial tibial muscle of experimentally denervated rats. METHODS: Thirty-six Wistar rats were divided into four groups: the Initial Control Group, Final Control Group, Experimental Denervated and Treated Group, Experimental Denervated Group. The electrostimulation was performed with a protocol of Russian current applied three times per week, for 45 days. At the end, the animals were euthanized and histological and morphometric analyses were performed. Data were submitted to statistical analysis with a significance level of p<0.05. RESULTS: The Experimental Denervated Group and the Experimental Denervated and Treated Group had cross-sectional area of smaller fiber compared to the Final Control Group. However, there was significant difference between the Experimental Denervated Group and Experimental Denervated and Treated Group, showing that electrical stimulation minimized muscle atrophy. The Experimental Denervated and Treated Group and Initial Control Group showed similar results. CONCLUSION: Electrical stimulation through Russian current acted favorably in maintaining morphology of the cranial tibial muscle that was experimentally denervated, minimizing muscle atrophy. OBJETIVO: Investigar se a estimulação elétrica pela corrente russa é capaz de manter a morfologia do músculo tibial cranial de ratos desnervados experimentalmente. MÉTODOS: Foram utilizados 36 ratos Wistar, distribuídos em quatro grupos: Grupo Controle Inicial, Grupo Controle Final, Grupo Experimental Desnervado Tratado, Grupo Experimental Desnervado. A eletroestimulação foi realizada com um protocolo de corrente russa aplicada três vezes por semanas, durante 45 dias. Ao final, os animais foram eutanasiados e, em seguida, foram realizadas as análises histológica e morfométrica. Os dados foram submetidos à análise estatística, com nível de significância de p<0,05. RESULTADOS: Os Grupos Experimental Desnervado e o Grupo Experimental Desnervado Tratado apresentaram área de secção transversal da fibra menor quando comparados ao Grupo Controle Final. Entretanto, constatou-se diferença significativa entre o Grupo Experimental Desnervado e o Grupo Experimental Desnervado Tratado, mostrando que a estimulação elétrica minimizou atrofia muscular. Ainda, observou-se que o Grupo Experimental Desnervado Tratado apresentou resultados semelhantes ao Grupo Controle Inicial. CONCLUSÃO: A estimulação elétrica por meio da corrente russa foi favorável na manutenção da morfologia do músculo tibial cranial desnervado experimentalmente, minimizando a atrofia muscular.