Anatomical principles of ankle denervation - An update.

BACKGROUND: Denervation is a surgical option in ankle arthrosis when conservative therapy has failed. Sectioning all joint branches is essential for its success. The locations of the articular branches of the saphenous (Sa), tibial (Ti), sural (Su), superficial (Ps) and deep peroneal (Pp) nerves are specified. METHODS: In 16 cryopreserved specimens, the courses of the nerves were prepared. Their articular branches were identified, and their respective locations documented by using a new reference system. RESULTS: The articular branches to the ankle ranged from 5 to 30 cm measured from the foot sole. The Sa should be transected at 22.5 cm, the Su at 20 cm, and the Pp at 15 cm. The Ti should be skeletonized up to 25 cm. Epifascial dissection of the Ps is to be performed below 15 cm. CONCLUSION: The study specifies the joint branches of the ankle in an intraoperatively reproducible reference system and thus minimizes the required skin incisions.

Proximity of percutaneous tibial nerve stimulation needle insertion to surrounding anatomic structures: a cadaveric study.

BACKGROUND: Percutaneous tibial nerve stimulation is a third-line treatment for overactive bladder and urgency urinary incontinence. During the procedure, a needle is inserted cephalad to the medial malleolus and posterior to the tibia. In recent years, permanent implants and leads have been developed for insertion into the medial ankle via a small incision. There are many important structures present in the medial compartment of the ankle, including the great saphenous vein, saphenous nerve, tibial nerve, posterior tibial vessels, and tendons of the posterior compartment leg muscles. OBJECTIVE: The primary objective of this study was to identify the proximity of the percutaneous tibial nerve stimulation needle placed per Food and Drug Administration-approved device instructions to nearby important anatomic structures. The secondary objectives were to identify the proximity of the tibial nerve to the needle site, identify clinically relevant ankle anatomic structures, and confirm the tibial nerve and posterior tibial vasculature by histologic analysis. STUDY DESIGN: Detailed medial ankle dissections were performed bilaterally on 10 female lightly embalmed anatomic donors (cadavers) obtained from the Willed Body Program at the University of Louisville. A pin was inserted at the percutaneous tibial nerve stimulation needle site, and the medial ankle was minimally dissected so the surrounding anatomic structures were visible but not disrupted. The shortest distance from the pin to the selected structures of the medial ankle region was measured. On completion of each dissection and set of measurements, tissue was harvested for histologic examination. The distances between the pin and each structure were assessed using means and standard deviations. A paired t test was used to assess the difference in the locations between the left and right ankles. Statistical analysis was performed on left-sided, right-sided, and combined measurements. An 80% prediction interval was found to represent the expected range of values for the measurement of a new cadaver or patient, and the 95% confidence interval of the mean was computed to characterize the average distance across all cadavers or patients. RESULTS: The medial ankle of 10 adult female lightly embalmed cadavers were examined bilaterally. Dissections were completed from October 2021 to July 2022. Of note, 80% prediction intervals for the tibial nerve, the posterior tibial artery or vein, and the flexor digitorum longus tendon had a lower range of 0.0 mm from the pin and extending to 12.1, 9.5, and 13.9 mm, respectively. Moreover, 2 of the structures were found to be asymmetrical between the right and left ankles. The great saphenous vein was further from the pin on the left (20.5 mm [standard deviation of 6.4 mm] on the left vs 18.1 mm [standard deviation of 5.3 mm] on the right; P=.04). The calcaneal (Achilles) tendon was further from the pin on the right side (13.2 mm [standard deviation of 6.8 mm] vs 7.9 mm [standard deviation of 6.7 mm]; P=.04). Tibial neurovascular structures were confirmed with microscopic analysis. CONCLUSION: The anatomic structures within the medial ankle lie unexpectedly close to the percutaneous tibial nerve stimulation needle site as noted per Food and Drug Administration-approved device instructions. There is a possibility that some medial ankle structures are not symmetrical. It is crucial that practitioners understand medial ankle anatomy when performing percutaneous tibial nerve stimulation or permanent device insertion.

[Ultrasound-guided radiofrequency ablation of the sural nerve for chronic ankle pain: A case report]. / Técnica de radiofrecuencia ablativa ecoguiada del nervio sural para el dolor crónico de tobillo. A propósito de un caso.

Chronic lateral ankle pain related to sural neuralgia is a rare pathology. The sural nerve innervates the sensitivity of the posterolateral border of the leg, as well as the dorsolateral border of the foot. On occasions, sural neuralgia is resistant to conservative treatment and can affect the patient's psycho-emotional and social sphere. We describe the case of a 54-year-old patient with neuropathic pain in the sural territory and a history of several ankle surgeries. After unsuccessful conservative treatment, ultrasound-guided ablative radiofrequency is performed in the sural nerve with subsequent complete cessation of pain without side effects. We propose to give importance to ecopalpation in the consultation of a rehabilitation physician, as well as to describe ultrasound-guided ablative radiofrequency as a safe and effective technique for sural neuralgia that does not respond to conservative treatment. However, more quality studies are needed to corroborate these results.

Sural nerve: imaging anatomy and pathology.

High resolution ultrasound (US) and magnetic resonance (MR) neurography are both imaging modalities that are commonly used for assessing peripheral nerves including the sural nerve (SN). The SN is a cutaneous sensory nerve which innervates the lateral ankle and foot to the base of the fifth metatarsal. It is formed by contributing nerves from the tibial and common peroneal nerves with six patterns and multiple subtypes described in literature. In addition to the SN being a cutaneous sensory nerve, the superficial location enables the nerve to be easily biopsied and harvested for a nerve graft, as well as increasing the susceptibility to traumatic injury. As with any peripheral nerves, pathologies such as peripheral nerve sheath tumors and neuropathies can also affect the SN. By utilizing a high frequency probe in US and high-resolution MR neurography, the SN can be easily identified even with the multiple variations given the standard distal course. US and MRI are also useful in determining pathology of the SN given the specific image findings that are seen with peripheral nerves. In this review, we evaluate the normal imaging anatomy of the SN and discuss common pathologies identified on imaging.

Bloqueo de tobillo ecoguiado en paciente con síndrome de Ledderhosepara intervención bajo régimen ambulatorio / Ultrasound-guided ankle block in a patient with Ledderhose syndrome for outpatient surgery

El bloqueo de tobillo ecoguiado resulta una técnica anestésica segura y eficaz en la cirugía de pie bajo régimen ambulatorio. Su principal ventaja respecto a otras técnicas regionales, como el bloqueo del nervio ciático, es la ausencia de bloqueo motor proximal al tobillo, permitiendo una deambulación precoz tras la cirugía. Se presenta el caso clínico de un paciente con síndrome de Ledderhose, en el cual se realiza fasciectomía plantar subtotal mediante bloqueo ecoguiado del pie en régimen ambulatorio (AU)

The ultrasound-guided ankle block is a safe and effective anesthetic technique for outpatient foot surgery. Its main advantage over other regional techniques such as sciatic nerve block is the absence of motor block proximal to the ankle, allowing early ambulation after surgery. We report a case of a patient with Ledderhose Syndrome, in which we perform subtotal plantar fasciectomy on an outpatient basis (AU)

Gait Characteristics Following Stroke: A Prospective Crossover Study to Compare Ankle-Foot Orthosis with Functional Electrical Stimulation.

Background: Management of foot-drop following stroke can be addressed with ankle-foot orthosis (AFO) or functional electrical stimulation (FES) of the peroneal nerve. There is limited evidence regarding the efficacy of FES as a substitute for a conventional ankle-foot orthosis. Objective: The aim of this study was to compare efficacy of FES against AFO in management of foot-drop in patients following stroke. Materials and Methods: Twenty patients (ten per group) were enrolled in this prospective crossover trial. Group A patients received gait training with AFO during first week followed by training with FES during second week and vice-versa for group B. Outcome parameters following AFO/FES training included Ten-meter, Six-minute walk test and spatiotemporal gait parameters. Patient satisfaction level was assessed using feedback questionnaire. Friedman test and Wilcoxon signed-rank test were performed to compare outcomes between barefoot, AFO and FES. The P value < 0.05 was considered statistically significant. Results: Nineteen males and one female aged 45.5 ± 9.45 years were recruited. Statistically significant improvement was observed in Ten-meter and Six-minute walk tests, gait speed, Timed up and go test (TUG), stance-swing ratio and single-limb support among users of FES as compared to AFO and barefoot. There was no statistical difference observed in other gait parameters. Physiological cost index (PCI) showed trend in improvement among FES users. Patient satisfaction scores were higher for FES users. Conclusions: Quantitative and qualitative results were in favour of FES as compared to AFO and barefoot suggesting that FES can be a potential orthotic intervention in hemiplegic patients.

"High ankle block" for surgery at the ankle joint.

BACKGROUND: Surgery around the ankle is increasingly embedded in outpatient treatment concepts. Unfortunately, the classic "ankle block" as a concept of regional anesthesia is inappropriate for surgery around the ankle because the injection sites are too distal to block this specific region. METHODS: The "high ankle block" avoids this disadvantage by dislocating the injection points 15 cm proximal to the malleoli. Three of five peripheral nerves necessary to perform the block can be reached by a circumferential subcutaneous wall. The Posterior Tibial Nerve and the Deep Peroneal Nerve are addressed by an ultrasound guided approach. RESULTS: The efficacy of the technique is highlighted by a case series (3 cases) in which the new blockade was used as a stand-alone procedure, i.e. without additional general anesthesia. CONCLUSIONS: The "high ankle block" may serve as an ultrasound guided expansion to the classic techniques, extending the operative spectrum to the ankle region.

Imaging of Entrapment Neuropathies in the Ankle.

Entrapment neuropathies of the ankle and foot pose a major diagnostic challenge and thus remain underdiagnosed. Recent advancements in imaging modalities, including magnetic resonance neurography (MRN), have resulted in considerable improvement in the anatomical localization and identification of pathologies leading to nerve entrapment. MRN supplements clinical examination and electrophysiologic studies in the diagnosis of neuropathies, aids in assessing disease severity, and helps formulate management strategies. A comprehensive understanding of the anatomy and imaging features of the ankle is essential to diagnose and manage entrapment neuropathies accurately. Advancements in imaging and their appropriate utilization will ultimately lead to better diagnoses and improved patient outcomes.

Complications Associated with Peripheral Nerve Blocks.

Outpatient orthopedic surgery is gradually becoming the standard across the country, as it has been found to significantly lower costs without compromising patient care. Peripheral nerve blocks (PNBs) are largely what have made this transition possible by providing patients excellent pain control in the immediate postoperative period. However, with the increasing use of PNBs, it is important to recognize that they are not without complications. Although rare, these complications can cause patients a significant amount of morbidity. It is important for surgeons to know the risks of peripheral nerve blocks and to inform their patients.

An MRI study of the tibial nerve in the ankle canal and its branches: a method of multiplanar reformation with 3D-FIESTA-C sequences.

BACKGROUND: The visualization of the tibial nerve and its branches in the ankle canal is helpful for the diagnosis of local lesions and compression, and it is also useful for clinical observation and surgical planning. The aim of this study was to investigate the feasibility of three-dimensional dual-excitation balanced steady-state free precession sequence (3D-FIESTA-C) multiplanar reformation (MPR) display of the tibial nerve and its branches in the ankle canal. METHODS: The subjects were 20 healthy volunteers (40 ankles), aged 22-50 years, with no history of ankle joint disease. The 3D-FIESTA-C sequence was used in the 3.0 T magnetic resonance equipment for imaging. During scanning, each foot was at an angle of 90° to the tibia. The tibial nerve of the ankle canal and its branches were displayed and measured at the same level through MPR. RESULTS: Most of the tibial nerve bifurcation points were located in the ankle canal (57.5%), few bifurcation points (42.5%) were located at the proximal end of the ankle canal, and none of them were found away from the distal end. The bifurcation between the medial plantar nerve and the lateral plantar nerve was on the line between the tip of the medial malleolus and the calcaneus, and it's angle ranged between 6° and 35°. In MPR images, the display rates of both the medial calcaneal nerve and the subcalcaneal nerve were 100%, and the starting point of the subcalcaneal nerve was always at the distal end of the starting point of the medial calcaneal nerve. In 55% of cases, there were more than two medial calcaneal nerve innervations. CONCLUSION: The 3D-FIESTA-C MPR can display the morphological features and positions of the tibial nerve and its branches and the bifurcation point's projection position can be marked on the body surface. This method not only benefited the imaging diagnosis of the tibial nerve and branch-related lesions in the ankle canal, but it also provided a good imaging basis to plan a clinical operation of the ankle canal and avoid surgical injury.

The relationship of the Phantom® Lapidus Intramedullary Nail System to neurologic and tendinous structures in the foot: An anatomic study.

BACKGROUND: The purpose of our cadaveric study was to determine the proximity of nail insertion and interlocking mechanisms in the Phantom® Lapidus Intramedullary Nail System to neurologic and tendinous structures in the foot. METHODS: We used 10 fresh-frozen human lower-extremity specimen cadavers. For each specimen, the Nail System was inserted as described in the published technique guide. We then performed dissection on the tibialis anterior tendon, extensor hallucis longus tendon, and medial dorsal cutaneous branch of the superficial peroneal nerve and we measured and averaged the distances from each of these structures from the nail. RESULTS: The tibialis anterior tendon was in closest proximity to the insertion of the proximal medial interlock K-wire with an average distance of 0.4mm from the tendon. The extensor hallucis longus tendon was in closest proximity to nail insertion with an average distance of 1.2mm. The medial dorsal cutaneous branch of the superficial peroneal nerve was in closest proximity to the distal interlock K-wire with an average distance of 7.5mm. CONCLUSIONS: The tibialis anterior tendon, extensor hallucis longus tendon, and the medial dorsal cutaneous branch of the superficial peroneal nerve are at risk with the insertion of the nail system. Blunt dissection should be performed using this system with a path to bone before instrumentation to reduce the risk of nerve and tendon injury in the foot.

Ultrasound-Guided Proximal and Distal Tarsal Decompression: An Analysis of Pressures in the Tarsal, Medial Plantar, and Lateral Plantar Tunnels.

Objectives. To analyze the reliability of measurements of tarsal tunnel and medial and lateral plantar tunnel pressures before and after ultrasound-guided release. Measurements taken were guided by ultrasound to improve reliability. This novel approach may help surgeons make surgical decisions. The second objective was to confirm that decompression using ultrasound-guided surgery as previously described by the authors is technically effective, reducing pressure to the tarsal and medial and lateral plantar tunnels. Methods. The study included 23 patients with symptoms compatible with idiopathic tarsal tunnel syndrome (TTS). The first step was to measure intracompartmental pressure of the tarsal tunnel, medial plantar tunnel, and lateral plantar tunnel preoperatively. The second step was ultrasound-guided decompression of the tibial nerve and its branches. Subsequently, pressure was measured again immediately after decompression in the 3 tunnels. Results. After surgery, the mean values significantly dropped to normal values. This represents a validation of effective decompression of the tibial nerve and its branches in TTS with ultra-minimally invasive surgery. Conclusions. The ultrasound-guided surgical technique to release the tibial nerve and its branches is effective, significantly reducing pressure in the tunnels and, thereby, decompressing the nerves.Level of evidence: Level IV.

Lateral popliteal block in foot and ankle surgery: Comparing ultrasound guidance to nerve stimulation. A prospective randomized trial.

BACKGROUND: The popliteal block has several benefits in foot and ankle surgery. It reduces postoperative pain, limits the use of narcotics and facilitates early discharge. The aim of this prospective randomized trial was to evaluate whether ultrasound guidance improves block characteristics compared to the nerve stimulation technique in lateral popliteal blocks. METHODS: Patients were randomized to receive either a lateral popliteal block using neurostimulation or ultrasound guidance. Block performance time, number of needle pricks, number of redirections were recorded. Pain upon admission to and discharge from post anesthesia care unit (PACU) was recorded. Block duration, patient satisfaction, pain at block site and amount of opioids used in PACU and between subsequent followup visits was recorded. Patients were followed for 12 weeks postoperatively. RESULTS: There was no statistically significant difference between the two groups in terms of number of pricks, time for the block to wean, pain upon admission to PACU, amount of opioids received in PACU, pain upon discharge from PACU, pain at the operative site, pain at the block site, toe motor function and toe sensation. There was a statistically significant difference in the block procedure performance time between the two groups, with the control group being faster (P<0.0001). A significantly larger number of patients in the control group required more than three needle redirections (P=0.0060). CONCLUSIONS: The lateral sciatic popliteal block using nerve stimulation had similar block characteristics and patient satisfaction with a significantly faster performance time compared to the ultrasound guided technique. LEVEL OF EVIDENCE: Level I, prospective randomized study.

Ankle and Foot Spasticity Patterns in Chronic Stroke Survivors with Abnormal Gait.

Chronic stroke survivors with spastic hemiplegia have various clinical presentations of ankle and foot muscle spasticity patterns. They are mechanical consequences of interactions between spasticity and weakness of surrounding muscles during walking. Four common ankle and foot spasticity patterns are described and discussed through sample cases. The patterns discussed are equinus, varus, equinovarus, and striatal toe deformities. Spasticity of the primary muscle(s) for each deformity is identified. However, it is emphasized that clinical presentation depends on the severity of spasticity and weakness of these muscles and their interactions. Careful and thorough clinical assessment of the ankle and foot deformities is needed to determine the primary cause of each deformity. An understanding of common ankle and foot spasticity patterns can help guide clinical assessment and selection of target spastic muscles for botulinum toxin injection or nerve block.

Musculoskeletal ultrasonography combined with electromyography in the diagnosis of massage-inducted lateral plantar nerve injury: A case report.

INTRODUCTION: It is well known that foot massage is a very prevalent stress relief method in China. Literatures have reported various massage-inducted peripheral nerve injuries. However, massage-inducted lateral plantar nerve (LPN) injury is very rare. Here, we represent an unusual case of massage-inducted LPN damage, and we also report the diagnostic method of this patient using musculoskeletal ultrasonography combined with electromyography (EMG). PATIENT CONCERNS: A 21-year-old woman presented symptoms of redness, swelling, pain and numbness in the medial right ankle joint for 2 days. DIAGNOSIS: The results of musculoskeletal ultrasonography and EMG provide great help for doctors to make accurate diagnosis. The patient was eventually diagnosed with LPN injury. INTERVENTIONS: No further foot massage was allowed. Vitamin B12 was taken orally for 2 months. Conservative therapy, including electrical stimulation therapy and infrared therapy, was conducted. Besides, active rehabilitation training was also performed. OUTCOMES: The discomfort symptoms were relieved significantly after 2 months conservative treatment. Clinical symptoms and EMG examination illustrated satisfactory result during follow up time. CONCLUSION: The report showed that the masseur should be very careful when doing foot massage to prevent nerve damage. Besides, musculoskeletal ultrasonography combined with EMG can provide important evidence for accurate and effective diagnosis of LPN injury.

[Ankle block]. / Fußblock.

OBJECTIVE: The so-called ankle block represents a local anesthesia form which enables easy performance of all surgical procedures of the foot and ankle. INDICATIONS: Interventions distal to the medial and lateral malleoli. CONTRAINDICATIONS: Acute and chronic infections in the area of injection; allergy to the local anesthesia. SURGICAL TECHNIQUE: All five sensory foot nerves are blocked. The two deep lying nerves, the tibial nerve and the deep fibular nerve, can be directly anesthetized perineurally using anatomical landmarks. The other three nerves are subcutaneously infiltrated near their branches. RESULTS: The success rate ranges from 88 to 94%; smaller areas may also be further blocked intraoperatively. The ankle block is a cost-effective procedure which can also be performed without problems in multimorbid patients due to its minor side effects.

Central command increases muscle sympathetic nerve activity more to contracting than noncontracting muscle during rhythmic isotonic leg exercise.

We have previously shown that the increase in muscle sympathetic nerve activity (MSNA) to contracting muscle during sustained isometric exercise is due primarily to central command and that contracting muscle does not express a metaboreceptor-driven increase in MSNA. Here we tested the hypothesis that MSNA increases to the contracting muscle also during rhythmic isotonic exercise, in which muscle metabolites will not accumulate because the contraction is performed without external load. MSNA was recorded from the common peroneal nerve in 10 participants, and negative-going sympathetic spikes were extracted during 50 cycles of sinusoidal (0.15 Hz) isotonic dorsiflexions of the ipsilateral or contralateral ankle. Electromyographic activity (EMG) was recorded from the tibialis anterior muscle on both sides. Cross-correlation analysis between MSNA and EMG revealed a marked cyclic modulation of MSNA to the contracting (ipsilateral) muscle. This modulation, in which MSNA increased during the contraction phase, was three times greater than that to the noncontracting muscle (modulation index = 27.4 ± 3.2% vs. 9.2 ± 1.5%; P < 0.002). There were no differences in either the intensity or the magnitude of modulation of EMG during ipsilateral and contralateral contractions. We conclude that central command increases MSNA to the contracting muscle during rhythmic isotonic exercise. NEW & NOTEWORTHY Muscle sympathetic nerve activity (MSNA) increases to contracting muscle during isometric exercise, but whether this occurs during rhythmic isotonic exercise is unknown. We recorded MSNA to the pretibial flexors during cyclic dorsiflexion of the ipsilateral or contralateral ankle. MSNA showed a cyclic increase during the contraction phase that was significantly higher to the contracting than the noncontracting muscle, supporting central command as the primary mechanism responsible for increasing MSNA.

The development of functional and directed corticomuscular connectivity during tonic ankle muscle contraction across childhood and adolescence.

In adults, oscillatory activity in the sensorimotor cortex is coherent with contralateral muscle activity at beta frequencies (15-35 Hz) during tonic contraction. This functional coupling reflects the involvement of the sensorimotor cortex, the corticospinal pathway, and likely also ascending sensory feedback in the task at hand. However, little is known about the developmental trajectory of task-related corticomuscular connectivity relating to the voluntary control of the ankle muscles. To address this, we recorded electroencephalography (EEG) from the vertex (Cz) and electromyography (EMG) from ankle muscles (proximal and distal anterior tibial, TA; soleus, SOL; gastrocnemius medialis, GM) in 33 participants aged 7-23 yr during tonic dorsi- and plantar flexion requiring precise maintenance of a submaximal torque level. Coherence was calculated for Cz-TA, Cz-SOL, TA-TA, and SOL-GM signal pairs. We found strong, positive associations between age and beta band coherence for Cz-TA, Cz-SOL, and TA-TA, suggesting that oscillatory corticomuscular connectivity is strengthened during childhood development and adolescence. Directionality analysis indicated that the primary interaction underlying this age-related increase was in the descending direction. In addition, performance during dorsi- and plantar flexion tasks was positively associated with age, indicating more precise control of the ankle joint in older participants. Performance was also positively associated with beta band coherence, suggesting that participants with greater coherence also exhibited greater precision. We propose that these results indicate an age-related increase in oscillatory corticospinal input to the ankle muscle motoneuron pools during childhood development and adolescence, with possible implications for maturation of precision force control. Within the theoretical framework of predictive coding, we suggest that our results may reflect an age-related increase in reliance on feedforward control as the developing nervous system becomes better at predicting the sensory consequences of movement. These findings may contribute to the development of novel intervention strategies targeting improved sensorimotor control in children and adolescents with central motor disorders.

Pretreatment of ankle nerve block provides better postoperative analgesia than peri-incisional local anesthetic infiltration in hallux valgus correction surgery.

Adequate postoperative analgesia after hallux valgus (HV) correction surgery improves early mobilization and decreases hospital stay. Peripheral nerve block and peri-incisional local anesthetic (LA) infiltration are both widely used for pain management in orthopedic surgeries. The aim of this study was to compare the analgesic effects between the ankle block and peri-incisional infiltration technique in patients undergoing HV correction surgery. Ninety patients scheduled for hallux valgus correction surgery were randomly allocated into three groups. In group N, patients were pretreated with tibial and peroneal nerve blocks with 8-10 mL of 0.25% bupivacaine before surgery. In group P, patients received the same LA for peri-incisional infiltration preoperatively. In group C, patients underwent surgery without regional analgesic pretreatment. All patients had intravenous fentanyl patient control analgesia as part of multimodal postoperative pain management. Fentanyl consumption, rest and moving pain scale, and adverse effects were evaluated at postoperative 6 h (Poh6), Poh12, Poh 24, and Poh36, respectively. Patients receiving bilateral feet surgeries were excluded in this study. Seventy-five patients were enrolled into final analysis. The patients in group N expressed lower resting and moving pain scores at Poh6, but the pain scores turned similarly among the three groups following Poh12 and then. The total fentanyl consumption was significantly less in group N than in group P. The postoperative activities and mood disturbance were not significantly different between groups after Poh12 and then. We conclude that ankle block is better than peri-incisional LA infiltration in HV correction surgery in pain relief and fentanyl consumption.