A Patient with Tarsal Tunnel Syndrome Associated with the Flexor Digitorum Accessorius Longus Muscle.

The flexor digitorum accessorius longus muscle (ALM) can be overlooked as the eliciting factor in patients with tarsal tunnel syndrome (TTS), an entrapment neuropathy of the posterior tibial nerve that elicits sole numbness and pain. Most elicitations are idiopathic, however, mass lesions within the tarsal tunnel can be also implicated. We report an 80-year-old woman whose flexor digitorum ALM led to the onset of bilateral TTS. She had suffered numbness in both soles for 3 years. Magnetic resonance imaging (MRI) of the bilateral tarsal tunnel showed that the posterior tibial nerve was compressed by the arteriovenous complex and in contact with the flexor digitorum ALM. We diagnosed bilateral TTS based on her symptoms and imaging findings, and performed bilateral decompression surgery of the posterior tibial nerve under local anesthesia. The artery on both sides was dislocated for nerve decompression. Because the posterior tibial nerve on the right side was strongly compressed in ankle plantar flexion we excised a portion of the tendon compressing the nerve. Postoperatively her symptoms gradually improved and she reported surgical satisfaction 6 months after the operation. In patients with flexor digitorum ALM-related TTS, the effect of dynamic factors on MRI findings and on surgical treatment decisions must be considered. Intraoperatively, not only the flexor digitorum ALM, but also other potential etiologic factors eliciting TTS must be kept in mind.

Safety and efficacy of ultrasound-guided percutaneous flexor retinaculum release of the ankle: an anatomical study.

Background: Tarsal tunnel syndrome (TTS) is a condition in which the tibial nerve (TN) (or its terminal branches) is compressed by the flexor retinaculum (FR) and the deep fascia of the abductor hallucis muscle at the tarsal tunnel, causing symptoms that negatively impact the patient's quality of life, including numbness, a sensation of a foreign object, coldness, and pain. FR release via microtrauma using needle-knife has proven to be effective in China and is widely used by clinicians. The traditional acupotomy, however, is the "blind knife" treatment, which cannot guarantee patient safety due to risk of injury to important structures, particularly the neurovascular bundle. Compared with the conventional treatments, ultrasound-guided percutaneous FR release possesses noteworthy advantages including high efficacy and safety. Methods: Percutaneous release of the FR was performed on 51 formalin-fixed specimens. The specimens were divided into two groups: an ultrasound-guided acupotomy pushing group comprising 20 legs (group U) and a nonultrasound-guided acupotomy pushing group comprising 31 legs (group N). After high-frequency ultrasound exploration, those with clear vascular imaging were included in group U; otherwise, they were included in group N. The FR was released percutaneously, soft tissue was dissected layer by layer, and anatomical data were recorded. Results: There no cases of injury in group U (0%) and four in group N (12.9%). Among the different intervention methods, there were no significant differences in tissue injury types (χ2=2.80; P=0.09). The percentage of released FR in group U was 80.00% while that in group N was 61.29% (χ2=1.977; P=0.16), which did not represent a significant difference between the two groups. However, group U had a significantly greater release length than that in the group N (t=3.359; P=0.002), indicating that the flexor release length guided by ultrasound is significantly greater than the unguided one. Conclusions: Ultrasound-guided percutaneous release of the FR using a needle-knife can provide greater length and percentage of released FR while maintaining a comparable safety rate to the unguided procedure.

A Rare Case of Hallux Saltans Treated using Ultrasound-guided Intralesional Steroid Injection: A Case Report.

Introduction: Stenosing tenosynovitis is a condition characterized by the inflammation and constriction of the tendons within a fibro-osseous tunnel. Case Report: We present a case of a 38-year-old man who presented with hallux saltans, a rare manifestation of this condition which was successfully treated with intralesional steroid injection. The patient experienced significant relief from pain and improved function following the procedure. Conclusion: This case highlights the importance of considering stenosing tenosynovitis as a potential cause of hallux saltans and the efficacy of non-surgical interventions in its management.

Weight-bearing Ultrasound to Diagnose Talar Dislocation Causing Tarsal Tunnel Syndrome.

The neuropathic compression of the tibial nerve and/or its branches on the medial side of the ankle is called tarsal tunnel syndrome (TTS). Patients with TTS presents pain, paresthesia, hypoesthesia, hyperesthesia, muscle cramps or numbness which affects the sole of the foot, the heel, or both. The clinical diagnosis is challenging because of the fairly non-specific and several symptomatology. We demonstrate a case of TTS caused by medial dislocation of the talar bone on the calcaneus bone impacting the tibial nerve diagnosed only by ultrasound with the patient in the standing position.

Common Peroneal Nerve and Tarsal Tunnel Release Surgery in an Adolescent Male with Hunter Syndrome: Illustrative Case.

BACKGROUND: Children with Hunter syndrome have a high prevalence of nerve compression syndromes given the buildup of glycosaminoglycans in the tendon sheaths and soft tissue structures. These are often comorbid with orthopedic conditions given joint and tendon contractures due to the same pathology. While carpal tunnel syndrome and surgical treatment has been well-reported in this population, the literature on lower extremity nerve compression syndromes and their treatment in Hunter syndrome is sparse. OBSERVATIONS: We report the case of a 13-year-old male with a history of Hunter syndrome who presented with toe-walking and tenderness over the peroneal and tarsal tunnel areas. He underwent bilateral common peroneal nerve and tarsal tunnel releases, with findings of severe nerve compression and hypertrophied soft tissue structures demonstrating fibromuscular scarring on pathology. Post-operatively, the patient's family reported subjective improvement in lower extremity mobility and plantar flexion. LESSONS: In this case, peroneal and tarsal nerve compression were diagnosed clinically and treated effectively with surgical release and postoperative ankle casting. Given the wide differential of common comorbid orthopedic conditions in Hunter syndrome and the lack of validated electrodiagnostic normative values in this population, the history and physical examination and consideration of nerve compression syndromes are tantamount for successful workup and treatment of gait abnormalities in the child with Hunter syndrome.

Cut-off value for a normal posterior tibial nerve to diagnose tarsal tunnel syndrome amongst people of different race in Pretoria, South Africa.

INTRODUCTION: Posterior tibial nerve (PTN) cross-sectional area (CSA) reference values for the diagnosis of tarsal tunnel syndrome (TTS) using ultrasound imaging exist in several countries but not in South Africa (SA). Therefore, the objective was to measure the CSA reference values for PTN in SA. METHODS: Ultrasound CSA measurements of PTN in both ankles on 112 participants were performed, the mean measurement was recorded, and the effect of race, age, gender, and body mass index (BMI) were recorded. RESULTS: In this study, the primary variables age and BMI affect the CSA measurement of the PTN. A positive correlation was found between PTN asymptomatic size and age (r = 0.196, P < 0.05), size and BMI (r = 0.200, P < 0.05). Age (categories) had a mean value of 3.17 for the age group 36-45 years (95% confidence interval (CI) 2.9-3.4). The mean BMI was 30.0 kg/m2 (CI 28.57-31.08). As for the asymptomatic PTN, a mean CSA reference value of 0.10 cm2 was obtained. CONCLUSION: With increase in age and BMI, a greater PTN measurement will occur. Race appears to be a contributing factor, but further research is needed in this regard. The reference CSA value for normal PTN should be set at 0.10 cm2 for all racial groups for a basic musculoskeletal ultrasound exam protocol in South Africa.

Lateralizing calcaneal osteotomy performed with a percutaneous burr results in a significantly lower increase in tarsal tunnel pressure.

PURPOSE: Tarsal tunnel syndrome is well documented following lateralizing calcaneal osteotomy to manage varus hindfoot deformity. Traditionally, calcaneal osteotomy is performed with an oscillating saw. No studies have investigated the effect of alternative surgical techniques on postoperative tarsal tunnel pressure. The purpose of this study was to investigate the difference in tarsal tunnel pressures following lateralizing calcaneal osteotomy performed using a high-torque, low-speed "minimally invasive surgery" (MIS) Shannon burr versus an oscillating saw. METHODS: Lateralizing calcaneal osteotomy was performed on 10 below-knee cadaveric specimens. This was conducted on 5 specimens each using an oscillating saw (Saw group) or MIS burr (Burr group). The calcaneal tuberosity was translated 1 cm laterally and transfixed using 2 Kirschner wires. Tarsal tunnel pressure was measured before and after osteotomy via ultrasound-guided percutaneous needle barometer. Mean pre/post-osteotomy pressures were compared between groups. Differences were analyzed using Student's t test. RESULTS: The mean pre-procedure tarsal tunnel pressure was 25.8 ± 5.1 mm Hg in the Saw group and 26.4 ± 4.3 mm Hg in the Burr group (p = 0.85). The mean post-procedure pressure was 63.4 ± 5.1 in the Saw group and 47.8 ± 4.3 in the Burr group (p = 0.01). Change in tarsal tunnel pressure was significantly lower in the Burr group (21.4 ± 4.5) compared to the Saw group (37.6 ± 12.5) (p = 0.03). The increase in tarsal tunnel pressure was 43% lower in the Burr group. CONCLUSION: In this cadaveric study, tarsal tunnel pressure increase after lateralizing calcaneal osteotomy was significantly lower when using a burr versus a saw. This is likely because the increased width ("kerf") of the 3 mm MIS burr, compared to the submillimeter saw blade width, causes calcaneal shortening. Given the smaller increase in tarsal tunnel pressure, using the MIS burr for lateralizing calcaneal osteotomy may decrease the risk of postoperative tarsal tunnel syndrome. Future research in vivo should explore this.

Postoperative Outcomes Between Positive and Negative Electrodiagnosis in Patients With Tarsal Tunnel Syndrome: A Retrospective Comparative Study.

BACKGROUND: The sensitivity of diagnosing tarsal tunnel syndrome with an electrodiagnostic study is just over 50%. Given this low reliability, many surgeons prefer to make a diagnosis solely from a physical examination, despite reported electrodiagnostic findings. Thus, to understand the clinical ramifications between these 2 methods of diagnosis, this investigation compared the postoperative outcomes following a tarsal tunnel release between patients with positive and negative preoperative electrodiagnosis (EDx). METHODS: This study retrospectively reviewed 53 consecutive patients who underwent tarsal tunnel release by a single surgeon between 2015 and 2022. The primary outcome was pain level using visual analog scale (VAS) whereas the secondary outcomes were 36-Item Short Form Health Survey questionnaire, Foot and Ankle Ability Measure, recovery times (time to return to activities of daily living, work, and sports), and complications. Pre- and postoperative functional outcomes were compared within each EDx group using a paired sample t test. Postoperative outcomes between groups were compared using a generalized linear model adjusted for potential confounders. RESULTS: Both EDx groups (positive studies = 31 patients and negative studies = 22 patients) demonstrated significant improvement of all functional outcomes (P < .001). We found no significant difference in recovery time or postoperative outcomes between the 2 groups (P > .05). Multivariable analysis showed diabetes (risk ratio [RR] = 1.79, 95% CI 1.11-2.90) and longer duration of symptoms before surgery (RR = 1.02, 95% CI 1.00-1.04) as prognostic factors for residual pain following tarsal tunnel release. CONCLUSION: In our series, we found that preoperative electrodiagnostic results did not prognosticate postoperative functional outcomes or recovery times after tarsal tunnel release.

The Effectiveness of Indonesia's Seven - Step Return to Work Assessment on a Distal Tarsal Tunnel Syndrome : A Case Report Study.

Tarsal tunnel syndrome (TTS) is a nerve entrapment of the posterior tibial nerve. This uncommon condition frequently goes undiagnosed or misdiagnosed even though it interferes with the daily activities of workers. Here we discuss the return to work status of a 37-year-old male patient who manages a manufacturing plant. He was identified as having Tarsal Tunnel Syndrome as a result of a foot abnormality and improper shoe wear. He had moderate pes planus and underwent tarsal tunnel release on his right foot. What are the determinant factors in defining a patient's status for returning to work after a tarsal tunnel release? We conducted a literature review using PubMed, Science Direct, and Cochrane. The Indonesian Occupational Medicine Association used the seven-step return-to-work assessment as a protocol to avoid overlooking the process. Duration of symptoms, associated pathology, and the presence of structural foot problems or a space-occupying lesion are factors affecting outcome. Post-operative foot scores, including Maryland Foot Score (MFS), VAS, and Foot Function Index, can be used to evaluate patient outcomes. Early disability limitation and a thorough return-to-work assessment are needed.

Ganglia-Induced Tarsal Tunnel Syndrome.

BACKGROUND: Tarsal tunnel syndrome (TTS) is a common entrapment neuropathy that is sometimes elicited by ganglia in the tarsal tunnel. METHODS: Between August 2020 and July 2022, we operated on 117 sides with TTS. This retrospective study examined data from 8 consecutive patients (8 sides: 5 men, 3 women; average age 67.8 years) with an extraneural ganglion in the tarsal tunnel. We investigated the clinical characteristics and surgical outcomes for these patients. RESULTS: The mass was palpable through the skin in 1 patient, detected intraoperatively in 1 patient, and visualized on MRI scanning in the other 6 patients. Symptoms involved the medial plantar nerve area (n = 5), lateral plantar nerve area (n = 1), and medial and lateral plantar nerve areas (n = 2). The interval between symptom onset and surgery ranged from 4 to 168 months. Adhesion between large (≥20 mm) ganglia and surrounding tissue and nerves was observed intraoperatively in 4 patients. Of the 8 patients, 7 underwent total ganglion resection. There were no surgery-related complications. On their last postoperative visit, 3 patients with a duration of symptoms not exceeding 10 months reported favorable outcomes. CONCLUSIONS: Because ganglia eliciting TTS are often undetectable by skin palpation, imaging studies may be necessary. Early surgical intervention appears to yield favorable outcomes.

[Ultrasound of nerves of the lower extremities]. / Nervensonographie der unteren Extremitäten.

The ability to visualize the nerves of the lower extremities differs from that of the upper extremities in sonography because the soft tissue cover is significantly larger in some cases. Landmarks are also defined for the lower extremities, which enable precise visualization of the nerves. Nerves and muscles are to be understood as a functional unit. In addition to the clarification of nerve compression syndromes, polyneuropathies and nerve tumors, sonography is also used to visualize muscle atrophy.

An anatomical approach to the tarsal tunnel syndrome: what can ankle's medial side anatomy reveal to us?

BACKGROUND: The heel is a complex anatomical region and is very often the source of pain complaints. The medial heel contains a number of structures, capable of compressing the main nerves of the region and knowing its anatomical topography is mandatory. The purpose of this work is to evaluate if tibial nerve (TN) and its main branches relate to the main anatomical landmarks of the ankle's medial side and if so, do they have a regular path after emerging from TN. METHODS: The distal part of the legs, ankles and feet of 12 Thiel embalmed cadavers were dissected. The pattern of the branches of the TN was registered and the measurements were performed according to the Dellon-McKinnon malleolar-calcaneal line (DML) and the Heimkes Triangle (HT). RESULTS: The TN divided proximal to DML in 87.5%, on top of the DML in 12,5% and distal in none of the feet. The Baxter's nerve (BN) originated proximally in 50%, on top of the DML in 12,5% and distally in 37.5% of the cases. There was a strong and significant correlation between the length of DML and the distance from the center of the medial malleolus (MM) to the lateral plantar nerve (LPN), medial plantar (MPN) nerve, BN and Medial Calcaneal Nerve (MCN) (ρ: 0.910, 0.866, 0.970 and 0.762 respectively, p <  0.001). CONCLUSIONS: In our sample the TN divides distal to DML in none of the cases. We also report a strong association between ankle size and the distribution of the MPN, LPN, BN and MCN. We hypothesize that location of these branches on the medial side of the ankle could be more predictable if we take into consideration the distance between the MM and the medial process of the calcaneal tuberosity.

Tarsal tunnel ganglion cyst: intraneural or extraneural site?

Intraneural ganglion cysts are very uncommon lesions, whose diagnosis has increased since the articular theory and the description of the MRI findings were established. We present a case report of a 59-year-old man with symptoms of tarsal tunnel syndrome. Foot and ankle MRI demonstrated the presence of an intraneural cystic lesion in the posterior tibial neve and its connection with the subtalar joint through an articular branch. The identification of the specific radiological signs like the «signet ring sign¼ allowed establishing an adequate preoperative diagnosis, differentiating it from an extraneural lesion and facilitating the articular disconnection of the nerve branch during surgery.

Sonographic assessment of the tarsal tunnel compared to cadaveric findings: a pictorial study.

Aim of the study: To present the anatomy of the tarsal tunnel and demonstrate the utility of high-resolution ultrasound for tarsal tunnel examination. Materials and methods: Anatomical dissection was performed on a defrosted cadaveric model to demonstrate relevant anatomical structures of the tarsal tunnel, namely tendons, vessels and nerves. The tibial nerve division was demonstrated; the bifurcation of the tibial nerve into the medial and lateral plantar nerve, two medial calcaneal nerve branches were identified originating from the tibial nerve and the Baxter's nerve was identified as the first branch of the lateral plantar nerve. An ultrasound examination of the tarsal tunnel region was performed on a healthy volunteer. A linear probe was used and sonographic images were obtained at different levels of the tarsal tunnel: the proximal tarsal tunnel, the tibial nerve division into the medial and lateral plantar nerves, the distal tarsal tunnel, the Baxter's nerve branching point and the Baxter's nerve crossing between the abductor hallucis and quadratus plantae muscle. Results: Sonographic images were correlated with anatomical structures exposed during cadaveric dissection. Conclusions: We presented the anatomic-sonographic correlation of the tarsal tunnel and showed that high-resolution ultrasound is a useful imaging modality for tarsal tunnel assessment.

Magnetic Resonance Neurography of the Foot and Ankle.

Peripheral neuropathies of the foot and ankle can be challenging to diagnose clinically due to concomitant traumatic and nontraumatic or degenerative orthopedic conditions. Although clinical history, physical examination, and electrodiagnostic testing comprised of nerve conduction velocities and electromyography are used primarily for the identification and classification of peripheral nerve disorders, MR neurography (MRN) can be used to visualize the peripheral nerves as well as the skeletal muscles of the foot and ankle for primary neurogenic pathology and skeletal muscle denervation effect. Proper knowledge of the anatomy and pathophysiology of peripheral nerves is important for an MRN interpretation.

The role of ultrasound-guided perineural injection of the tibial nerve with a sub-anesthetic dosage of lidocaine for the diagnosis of tarsal tunnel syndrome.

Background: Tarsal tunnel syndrome (TTS) involves entrapment of the tibial nerve at the medial ankle beneath the flexor retinaculum and its branches, the medial and lateral plantar nerves, as they course through the porta pedis formed by the deep fascia of the abductor hallucis muscle. TTS is likely underdiagnosed, because diagnosis is based on clinical evaluation and history of present illness. The ultrasound-guided lidocaine infiltration test (USLIT) is a simple approach that may aid in the diagnosis of TTS and predict the response to neurolysis of the tibial nerve and its branches. Traditional electrophysiological testing cannot confirm the diagnosis and only adds to other findings. Methods: We performed a prospective study of 61 patients (23 men and 38 women) with a mean age of 51 (29-78) years who were diagnosed with idiopathic TTS using the ultrasound guided near-nerve needle sensory technique (USG-NNNS). Patients subsequently underwent USLIT of the tibial nerve to assess the effect on pain reduction and neurophysiological changes. Results: USLIT led to an improvement in symptoms and nerve conduction velocity. The objective improvement in nerve conduction velocity can be used to document the pre-operative functional capacity of the nerve. USLIT may also be used as a possible quantitative indicator of whether the nerve has the potential to improve in neurophysiological terms and ultimately inform prognosis after surgical decompression. Conclusion: USLIT is a simple technique with potential predictive value that can help the clinician to confirm the diagnosis of TTS before surgical decompression.

Impact of Dynamic Change of Meandering of Parallel Artery to the Idiopathic Tarsal Tunnel Syndrome.

In idiopathic tarsal tunnel syndrome (TTS), walking seems to make symptoms worse. The findings imply that an ankle movement dynamic component may have an impact on the etiology of idiopathic TTS. We describe how the ankle movement affects the nerve compression caused by the surround tissue, particularly the posterior tibial artery. We enrolled 8 cases (15 sides) that had TTS surgery after tarsal tunnel (TT) MRI preoperatively. Dorsiflexion and plantar flexion were the two separate ankle positions used for the T2* fat suppression 3D and MR Angiography of TT. Based on these findings, we looked at how the two different ankle positions affected the posterior tibial artery's ability to compress the nerve. Additionally, we assessed the posterior tibial artery's distorted angle. We divided the region around the TT into four sections: proximal and distal to the TT and proximal half and distal half to the TT. Major compression cause was posterior tibial artery. Most severe compression point was proximal half in the TT in all cases without one case. In each scenario, the nerve compression worsens by the plantar flexion. The angle of the twisted angle of the posterior tibial artery was significantly worsened by the plantar flexion. In idiopathic TTS, deformation of posterior tibial artery was the primary compression component. Nerve compression was exacerbated by the plantar flexion, and it was attributable with the change of the distorted angle of the posterior tibial artery. This could be a contributing factor of the deteriorating etiology by walking in idiopathic TTS.

The bifurcation and topography of the posterior tibial artery within the tarsal tunnel.

PURPOSE: The tarsal tunnel (TT) is a fibro-osseous anatomical space coursing from the medial ankle to the medial midfoot. This tunnel acts as a passage for both tendinous and neurovascular structures, including the neurovascular bundle containing the posterior tibial artery (PTA), posterior tibial veins (PTVs) and tibial nerve (TN). Tarsal tunnel syndrome (TTS) is the entrapment neuropathy that describes the compression and irritation of the TN within this space. Iatrogenic injury to the PTA plays a significant role in both the onset and exacerbation of TTS symptoms. The current study aims to produce a method to allow clinicians and surgeons to easily and accurately predict the bifurcation of the PTA, to avoid iatrogenic injury during treatment of TTS. METHODS: Fifteen embalmed cadaveric lower limbs were dissected at the medial ankle region to expose the TT. Various measurements regarding the location of the PTA within the TT were recorded and multiple linear regression analysis performed using RStudio. RESULTS: Analysis provided a clear correlation (p < 0.05) between the length of the foot (MH), length of hind-foot (MC) and location of bifurcation of the PTA (MB). Using these measurements, this study developed an equation (MB = 0.3*MH + 0.37*MC - 28.24 mm) to predict the location of bifurcation of the PTA within a 23° arc inferior to the medial malleolus. CONCLUSIONS: This study successfully developed a method whereby clinicians and surgeons can easily and accurately predict the bifurcation of the PTA, to avoid iatrogenic injury that would previously lead to an exacerbation of TTS symptoms.