Tarsal Tunnel Syndrome Treatment & Management

Medical therapy for tarsal tunnel syndrome may consist of local injection of steroids into the tarsal canal. An acceptable conservative approach in the early treatment of tarsal tunnel neuropathy includes the use of local anesthetics and soluble steroids, which may aid in the reduction of the patient's pain. These therapies may occasionally produce complete relief of symptoms, but they need to be performed judiciously, as additional nerve injury may occur from improperly placed syringe needles. Physical therapy may be of some value in reducing local soft-tissue edema, thereby easing pressure on the compartment.

Also, in symptomatic patients who exhibit a contracture of the gastrocnemius muscle of the triceps surae, stretching exercises that are designed to improve the flexibility of the gastrocnemius should be initiated. In cases in which the patient has a pes planovalgus foot type, a well-designed foot orthosis may reduce tension on the tibial nerve by decreasing the load on the medial column. This is accomplished by providing a medial longitudinal posting on the orthotic for both the hindfoot and forefoot.

The use of night splints with the foot in plantar flexion and varus may be considered in patients with a valgus foot. The long-term efficacy of this modality lacks well-controlled comparison studies with outcome measures, but it is commonly used in clinical practice.^[14]

When conservative therapy fails to alleviate the patient's symptoms, surgical intervention may be warranted. Space-occupying masses require removal. Numerous reports exist of neurilemoma of the tibial nerve, which may need to be removed. A thorough knowledge of the local anatomy is a prerequisite before attempting release of the affected nerve.

External neurolysis of the nerve may be necessary if surgical exploration demonstrates adhesions or scar tissue as the cause of the nerve impingement. Moreover, if scarring or entrapment encapsulates the nerve tissue, in addition to external neurolysis, a release of the epineurium is warranted.

The patient may be placed in either the supine or the lateral recumbent position to facilitate exposure of the medial aspect of the operative foot. Use of a pneumatic tourniquet is recommended.

A curved incision should be made approximately 1 cm posterior to the distal tibia and carried in the plantar direction, paralleling the shaft and malleolus and curving gradually toward the sustentaculum tali. The retinaculum should be identified and carefully released in its entirety. The posterior tibial nerve should be identified, visualized, and left undisturbed along the course until its bifurcation at the porta pedis. Care should be exercised to avoid cutting the small calcaneal branches that arise from the posterior tibial nerve; these branches are often surrounded by fatty tissue and may be difficult to easily visualize.

The medial plantar branch of the posterior tibial nerve should be identified and traced along the margin of the flexor sheath of the hallucis longus. The lateral branch should be followed into the abductor hallucis. Any fibrous bands that are noted to be constricting the nerves should be carefully released.

After release, all the branches of the tibial nerve should be lying free of any fascial covering. The tourniquet should be deflated to observe for and control bleeding. A layered closure should be performed, including the subdermal layer but not the flexor retinaculum. The skin may be closed with sutures or staples; a drain is not necessary. In a tarsal tunnel release, a layer closure of the wound should be performed by taking care not to reapproximate the extensor retinaculum, because this is the most common cause of the entrapment neuropathy.

A mild compression dressing and the initial immobilization should be applied with slight inversion to the affected area by using a splint for 3 weeks of non — weight bearing. After the splint is discontinued, the patient may begin joint mobilization and a graduated return to weight bearing.

The patient should be non — weight bearing for a period of 3 weeks to allow for proper healing. Early mobilization should be initiated to decrease the formation of scar tissue, which may itself contribute to compression neuropathy. The use of surgical shoe aids in reducing pressure on the surgical site is recommended. Formal physiotherapy may be helpful for the patient to regain strength and motion and for the relief of residual pain.

After suture removal, the patient should be able to resume the use of soft shoes, taking care to avoid shoes that may cause pressure or irritation of the surgical site. In patients who have a pes planus foot type, insole orthoses should be considered to stabilize the medial column.

Because of the anatomy of the affected region, several complications of compression release surgery may arise, most of which can be minimized with meticulous dissection and careful identification of the local anatomy.

Laceration of the nerve or posterior artery could have significant deleterious effects on foot function. A failure to adequately release the retinaculum along its entire course may lead to poor postoperative results. This is the most likely etiology of surgical failure.

Additionally, associated plantar fasciitis may be a cause of persistent pain in the medial heel region after decompression, which may need to be addressed separately. A case study by Kim and Dellon demonstrated that a neuroma of the distal saphenous nerve may need to be considered as a causative factor if pain continues after surgical release.^[15]

Properly performed decompression may yield satisfactory results. An initial marked decrease in pain and paresthesias may occur, followed by a reduction of symptoms to the extent that the patient may be able to tolerate the symptoms. Complete resolution of symptoms may not be possible because the disorder has numerous etiologies and because the likelihood of irreversible nerve damage exists. An increase in pain after decompression, however, is extremely rare.

Studies by Mann demonstrated that approximately 75% of patients who undergo surgical decompression have appreciable pain relief, and 25% obtain little or no relief.^[16] Mann also stated that a repeat surgical exploration of a previous tarsal canal release rarely causes appreciable benefit to the patient.

Some concern exists regarding whether decompression of the tibial nerve in patients with marked pes planovalgus deformity may cause a deleterious effect because decompression of the medial retinacular compartment may be associated with an increase in nerve tension. Questions arise regarding whether a joint stabilization procedure may be a necessary adjunct in determining long-term postoperative success. To the author's knowledge, no studies have been performed to assess the long-term efficacy of decompression and stabilization, decompression and orthoses management, and decompression alone.