Tibial neuropathy is a lesion of N. tibialis of traumatic, compression, dysmetabolic or inflammatory genesis, leading to a violation of the function of the lower leg muscles responsible for plantar flexion of the foot and the foot muscles, hypesthesia of the posterior surface of the lower leg, sole and toes, the occurrence of pain syndrome and vegetative—trophic changes in the foot. In the diagnosis of pathology, the main one is the analysis of anamnestic data and neurological examination, auxiliary methods — EMG, ENG, ultrasound of the nerve, radiography and CT of the foot and ankle. Conservative treatment is possible (anti-inflammatory, neurometabolic, analgesic, vasoactive therapy) and surgical (neurolysis, decompression, removal of a nerve tumor).
General information
Tibial neuropathy is included in the group of so-called peripheral mononeuropathies of the lower extremities, which includes sciatic neuropathy, femoral neuropathy, fibular neuropathy, external cutaneous neuropathy of the thigh. The similarity of the clinic of tibial neuropathy with the symptoms of traumatic injuries of the musculoskeletal system of the lower leg and foot, as well as the traumatic etiology of most cases of the disease makes it the subject of study and joint management of specialists in the field of neurology and traumatology. The connection of the disease with sports overloads and repeated injuries determines the relevance of the problem for sports doctors.
Anatomy of the tibial nerve
The tibial nerve (n. tibialis) is a continuation of the sciatic nerve. Starting at the top of the popliteal fossa, the nerve passes it from top to bottom medially. Then, passing between the heads of the calf muscle, the nerve lies between the long flexor of the first finger and the long flexor of the fingers. So it reaches the medial ankle. Approximately in the middle between the ankle and the Achilles tendon, you can feel the point of passage of the tibial nerve. Next, the nerve enters the tarsal canal, where it, together with the posterior tibial artery, is fixed by a powerful ligament — the flexor retainer. Upon exiting the channel, n. tibialis is divided into terminal branches.
In the popliteal fossa and further, the tibial nerve gives motor branches to the triceps muscle, the flexor of the thumb and flexor of the fingers, the popliteal, posterior tibial and plantar muscles; the sensory internal cutaneous nerve of the lower leg, which together with the fibular nerve innervates the ankle joint, the posterolateral surface of the lower 1/3 of the lower leg, the lateral edge of the foot and the heel. The terminal branches of N. tibialis — medial and lateral plantar nerves — innervate the small muscles of the foot, the skin of the inner edge of the sole, the first 3.5 fingers and the back surface of the remaining 1.5 fingers. The muscles innervated by the tibial nerve provide flexion of the lower leg and foot, lifting of the inner edge of the foot (i.e. internal rotation), flexion, reduction and dilution of the toes, extension of their distal phalanges.
Causes
Femoral neuropathy is possible as a result of nerve injury in fractures of the lower leg, isolated fracture of the tibia, dislocation of the ankle joint, wounds, damage to tendons and sprains of the foot. Repeated sports injuries of the foot, deformities of the foot (flat feet, hallux valgus), prolonged uncomfortable position of the lower leg or foot with compression of the foot can also serve as an etiological factor. tibialis (often in alcoholism sufferers), diseases of the knee or ankle joint (rheumatoid arthritis, deforming osteoarthritis, gout), nerve tumors, metabolic disorders (in diabetes mellitus, amyloidosis, hypothyroidism, dysproteinemia), nerve vascularization disorders (for example, in vasculitis).
Most often, tibial neuropathy is associated with its compression in the tarsal canal (the so-called tarsal canal syndrome). Nerve compression at this level can occur with fibrous changes of the canal in the post-traumatic period, tendovaginitis, hematomas, bone exostoses or tumors in the canal area, as well as with neurodystrophic disorders in the ligamentous-muscular apparatus of the joint of vertebrogenic genesis.
Symptoms
Depending on the topic of the lesion of N. tibialis, several syndromes are distinguished in the clinical picture of its neuropathy.
Tibial neuropathy at the level of the popliteal fossa is manifested by a disorder of bending the foot down and a violation of movements in the toes of the foot. The patient cannot stand on his toes. Walking with an emphasis on the heel is typical, without rolling the foot on the toe. There is atrophy of the posterior muscle group on the lower leg and the muscles on the foot. As a result of atrophy of the muscles on the foot, it becomes like a clawed paw. There is a decrease in the tendon reflex from the achilles. Sensory disorders include violations of tactile and pain sensitivity on the entire lower leg from behind and along the outer edge of its lower 1/3, on the sole, totally (on the back and plantar surface) on the skin of the first 3.5 fingers and on the back of the remaining 1.5 fingers. Tibial neuropathy of traumatic origin is characterized by a pronounced causalgic syndrome with hyperpathy (perverted hypersensitivity), edema, trophic changes and vegetative disorders.
Tarsal canal syndrome in some cases is provoked by long walking or running. It is characterized by burning pains in the sole, often radiating into the calf muscle. Patients describe pain sensations as deep, note an increase in their intensity in the standing position and when walking. There is hypesthesia of both the inner and outer edges of the foot, some flattening of the foot and a slight “clawiness” of the fingers. The motor function of the ankle joint is preserved in full, the Achilles reflex is not impaired. Nerve percussion at the point between the inner ankle and the Achilles tendon is painful, gives a positive Tinel symptom.
Neuropathy at the level of the medial plantar nerve is typical for long-distance runners and marathon runners. Manifests pain and paresthesia on the inner edge of the sole and in the first 2-3 toes of the foot. Pathognomonic is the presence of a point in the navicular bone, the percussion of which leads to the appearance of burning pain in the thumb.
The lesion of N. tibialis at the level of the common finger nerves is called “Morton’s metatarsal neuralgia”. It is typical for older women who are obese and walk a lot in heels. Pain is typical, starting at the arch of the foot and going through the bases of 2-4 fingers to their tips. Walking, standing and running increase the pain syndrome. Examination reveals trigger points between 2-3 and/or 3-4 metatarsal bones, a symptom of Tinel.
Calcanodynia is a neuropathy of the calcaneal branches of the tibial nerve. It can be triggered by jumping on the heels from a height, long walking barefoot or in shoes with thin soles. It is manifested by pain in the heel, its numbness, paresthesia, hyperpathy. With the pronounced intensity of these symptoms, the patient walks without stepping on the heel.
Diagnostics
An important diagnostic value is the collection of anamnesis. Establishing the fact of injury or overload, the presence of joint pathology, metabolic and endocrine disorders, orthopedic diseases, etc. helps to determine the nature of damage to the tibial nerve. A thorough study of the strength of various muscle groups of the lower leg and foot, the sensitive area of this area, conducted by a neurologist; identification of trigger points and Tinel’s symptom makes it possible to diagnose the level of lesion.
Electromyography and electroneurography are of auxiliary importance. Determination of the nature of nerve damage can be carried out using ultrasound. According to the indications, X-ray of the ankle joint, X-ray of the foot or CT of the ankle joint is performed. In controversial cases, diagnostic blockade of trigger points is carried out, the positive effect of which confirms the compression nature of neuropathy.
Treatment
In cases where tibial neuropathy develops as a consequence of a background disease, treatment of the latter is necessary first of all. This can be wearing orthopedic shoes, therapy of arthrosis of the ankle joint, correction of endocrine imbalance, etc. In compression neuropathies, therapeutic blockades with triamcinolone, diprospane or hydrocortisone in combination with local anesthetics (lidocaine) give a good effect. It is mandatory to include in the list of prescriptions of drugs to improve metabolism and blood supply to the tibial nerve. These include injections of VIT B1, VIT B12, vit B6, nicotinic acid, drip administration of pentoxifylline, taking alpha-lipoic acid.
According to indications, reparants (actovegin, solcoxeril), anticholinesterase agents (neostigmine, ipidacrine) can be included in therapy. With intense pain syndrome and hyperpathy, it is recommended to take anticonvulsants (carbomazepine, pregabalin) and antidepressants (amitriptyll). Of the physiotherapeutic methods, ultraphonophoresis with hydrocortisone ointment, shock wave therapy, magnetotherapy, electrophoresis with hyaluronidase, UHF are the most effective. To restore the muscles that atrophy as a result of N. tibialis neuropathy, massage and exercise therapy are required.
Surgical treatment is necessary to remove formations that compress the trunk of the tibial nerve, as well as in case of failure of conservative therapy. The intervention is performed by a neurosurgeon. During the operation, decompression, removal of the nerve tumor, release of the nerve from adhesions, and neurolysis may be performed.