Pulsed radiofrequency under ultrasound guidance for the tarsal tunnel syndrome: two case reports

Comparison of tibial nerve pulsed radiofrequency and intralesional radiofrequency thermocoagulation in the treatment of painful calcaneal spur and plantar fasciitis: a randomized clinical trial

OBJECTIVE

Ultrasound-guided tibial nerve pulsed radiofrequency (US-guided TN PRF) and fluoroscopy-guided intralesional radiofrequency thermocoagulation (FL-guided intralesional RFT) adjacent to the painful calcaneal spur are two interventions for pain management in painful calcaneal spur and plantar fasciitis. This study aimed to compare the effectiveness of the two procedures.

DESIGN

A prospective, randomized, single-blind study.

SETTING

Single-center pain clinic.

SUBJECTS

Forty-nine patients who met the inclusion criteria were randomized into two groups.

METHODS

Group U (25 patients) received US-guided TN PRF at 42°C for 240 s, whereas Group F (24 patients) received FL-guided intralesional RFT at 80°C for 90 s. The most severe numeric rating scale (NRS) score during the first morning steps and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores were used to evaluate the effectiveness of the procedures. The study's primary outcome assessed treatment effectiveness via the NRS, whereas the secondary outcomes included changes in the AOFAS score and the incidence of procedure-related mild adverse events.

RESULTS

NRS and AOFAS scores significantly improved in Groups U and F at 1 and 3 months compared with baseline (P < .05), and there was no significant difference between the groups. At month 1, 50% or greater pain relief was achieved in 72% of patients in Group U and 75% of patients in Group F. No significant difference was observed in the incidence of mild adverse events between the groups.

CONCLUSIONS

US-guided TN PRF and FL-guided intralesional RFT have shown significant effectiveness in the treatment of painful calcaneal spur and plantar fasciitis. Larger randomized controlled trials are needed.

CLINICAL TRIAL NUMBER

NCT06240507.

Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment: A Systematic Review

Introduction

Posterior tarsal tunnel syndrome involves entrapment of the posterior tibial nerve as it travels in the groove posterior to the medial malleolus. Conventional wisdom dictates that patients with tarsal tunnel syndrome be treated with conservative treatment and medical management, with surgical options available for patients with refractory symptoms and good candidacy. Minimally invasive options for neuropathic entrapment syndromes have developed in recent years and may provide a therapeutic role in tarsal tunnel syndrome.

Objective

The present investigation provides a summary of the current state of knowledge on tarsal tunnel syndrome and a comparison between minimally invasive and surgical treatment options.

Methods

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

Results

Most commonly tarsal tunnel syndrome is idiopathic. Other reported causes include post-traumatic, lipomas, cysts, ganglia, schwannomas, ganglia, varicose plantar veins, anatomic anomalies, and systematic inflammatory conditions. Several risk factors have been described including female gender, athletic participation, hypothyroidism, diabetes mellitus, systemic sclerosis, chronic renal failure, and hemodialysis use. A few recent studies demonstrate anatomic variants that have not previously been summarized. Three articles describe clinical outcomes after conservative treatment with acceptable results for first line treatment. Two primary articles report on the use of minimally invasive treatment for tarsal tunnel syndrome. Fourteen articles report on the clinical outcomes after surgical management.

Conclusion

Clinical understanding of tarsal tunnel syndrome has evolved significantly, particularly with regards to the pathoanatomy of the tarsal canal over the past twelve years. A few novel anatomic studies shed light on variants that can be helpful in diagnosis. Conservative management remains a good option that can resolve the symptoms of many patients. As more prospective cohorts and clinical trials are performed on minimally invasive options, pulsed radiofrequency and neuromodulation may evolve to play a larger role in the treatment of this condition. Currently, surgical treatment is only pursued in a very select group of patients with refractory symptoms that do not respond to medical or minimally invasive options. Surgical outcomes in the literature are good and current evidence is stronger than that for minimally invasive options.

An Update on Posterior Tarsal Tunnel Syndrome

Posterior tarsal tunnel syndrome (PTTS) is an entrapment neuropathy due to compression of the tibial nerve or one of its terminal branches within the tarsal tunnel in the medial ankle. The tarsal tunnel is formed by the flexor retinaculum, while the floor is composed of the distal tibia, talus, and calcaneal bones. The tarsal tunnel contains a number of significant structures, including the tendons of 3 muscles as well as the posterior tibial artery, vein, and nerve. Focal compressive neuropathy of PTTS can originate from anything that physically restricts the volume of the tarsal tunnel. The variety of etiologies includes distinct movements of the foot, trauma, vascular disorders, soft tissue inflammation, diabetes mellitus, compression lesions, bony lesions, masses, lower extremity edema, and postoperative injury. Generally, compression of the posterior tibial nerve results in clinical findings consisting of numbness, burning, and painful paresthesia in the heel, medial ankle, and plantar surface of the foot. Diagnosis of PTTS can be made with the presence of a positive Tinel sign in combination with the physical symptoms of pain and numbness along the plantar and medial surfaces of the foot. Initially, patients are treated conservatively unless there are signs of muscle atrophy or motor nerve involvement. Conservative treatment includes activity modification, heat, cryotherapy, non-steroidal anti-inflammatory drugs, corticosteroid injections, opioids, GABA analog medications, tricyclic antidepressants, vitamin B-complex supplements, physical therapy, and custom orthotics. If PTTS is recalcitrant to conservative treatment, standard open surgical decompression of the flexor retinaculum is indicated. In recent years, a number of alternative minimally invasive treatment options have been investigated, but these studies have small sample sizes or were conducted on cadaveric models.

Painful Traumatic Neuromas in Subcutaneous Fat: Visibility and Morphologic Features With Ultrasound

OBJECTIVES

Subcutaneous neuromas usually result from trauma and may lead to dissatisfaction in patients with a trigger point, loss of sensitivity in the relevant territory of innervation, and spontaneous neuropathic pain. Confirming clinically suspected cases of neuroma may prove difficult. The objective of this study was to evaluate the visibility and morphologic features of traumatic subcutaneous neuromas of the limbs with ultrasound (US).

METHODS

Between January 2012 and August 2016, 38 consecutive patients clinically suspected of having subcutaneous neuromas were investigated with US. The diagnosis was confirmed on the basis of a focal morphologic abnormality of the nerve associated with trigger pain. Each neuroma was classified into 1 of 3 subtypes based on its injury pattern. The subtypes were terminal neuroma, spindle neuroma, and scar encasement, either isolated or associated with these subtypes.

RESULTS

Forty-four lesions were found in the 38 patients, including 29 spindle neuromas (65.9%), 14 terminal neuromas (31.8%) and 1 scar encasement with no nerve caliber abnormality (2.3%). Fifteen neuromas (35% of all neuromas) were associated with scar encasement. In 13 cases that required surgery, the diagnosis of neuroma or scar encasement could be surgically proven and confirmed the validity of the US findings.

CONCLUSIONS

Ultrasound can be used to show and classify subcutaneous nerves of the upper and lower limbs with high accuracy. The US trigger sign provides an indication of neuroma involvement in pain. This modality can play a substantial role both in the preoperative planning of neuroma surgery and in therapeutic US-guided procedures.

Ultrasound-Guided Release of the Tibial Nerve and Its Distal Branches: A Cadaveric Study

OBJECTIVES

The purpose of the study was to determine whether ultrasound (US)-guided surgery is a viable type of surgery for performing an effective release/decompression of the constricting structures that are responsible for focal nerve compression in tarsal tunnel syndrome.

METHODS

Ultrasound guidance was used on cadaveric specimens to delineate the anatomic course of the nerves and vessels in the medial ankle that comprise the structures involved in tarsal tunnel syndrome. Ultrasound guidance was used on cadaveric specimens and assisted in delineating a safe surgical zone to adequately and effectively release these constrictive structures of the proximal and distal tarsal tunnels. The US-guided tarsal tunnel release/decompression was performed through 2 small 1- to 2-mm portals. After US-guided release, anatomic dissection was used to check the efficacy (release of the flexor retinaculum and deep abductor hallucis muscle) and safety (absence of neurovascular or tendon injury) of the procedure.

RESULTS

In 12 fresh cadaveric specimens, US-guided release of the tibial nerve (proximal tarsal tunnel) and its branches (distal tarsal tunnel) at the medial ankle was effective in all 12 specimens (100% release rate), without any signs of compromise or injury into the neurovascular structures.

CONCLUSIONS

Ultrasound-guided tarsal tunnel release is a feasible surgical procedure that can be safe and effective with the proper training, although further investigation is warranted. This type of surgery may promote faster recovery with less postoperative morbidity, including pain, but this will be the subject of a further investigation.

Efficacy of Ultrasound-Guided Pulsed Radiofrequency for Recalcitrant Metatarsalgia A Case Report

Metatarsalgia is characterized by pain in the forefoot, which is associated with increased stress over the metatarsal head region. Despite the availability of a variety of conservative or surgical treatments for this condition, a few cases have demonstrated relapse or poor response to treatment. Pulsed radiofrequency (PRF) can provide pain relief in patients with diverse chronic conditions without causing neural injury. Recently, studies have shown that ultrasound-guided PRF may be beneficial for adhesive capsulitis, carpal tunnel syndrome, tarsal tunnel syndrome, and recalcitrant plantar fasciitis. Here, we describe a successful case of significant pain relief achieved by using ultrasound-guided PRF targeting the posterior tibial nerve (PTN) at the ankle of a 67-year-old woman with recalcitrant metatarsalgia. Ten minutes after ultrasound-guided PRF was applied at the PTN, the patient reported decreased pain (from 8 to 3 on a visual analogue scale) and did not exhibit any particular side effects. Three months after PRF application, the patient's visual analogue scale score remained more than 50% below the baseline, and she did not need additional conservative treatment during the follow-up period. To the best of our knowledge, we present the first case report using ultrasound-guided PRF at the PTN for treatment of recalcitrant metatarsalgia. We hypothesize that ultrasound-guided PRF at the PTN may be a potentially novel approach for treating recalcitrant metatarsalgia.