Morton's neuroma

The common phenomenon of nerve thickening in the intertarsal and metatarsophalangeal region of the lower extremity has many names, one of which is Morton's neuroma of the foot. Among other possible terms: Morton's disease or neuralgia, perineural plantar fibrosis, intertarsal neuroma, Morton's metatarsalgia syndrome, etc. All types of pathology are accompanied by severe pain when walking and limitation of movements in the foot area. Treatment is both conservative and surgical, depending on the indications. [1]

Epidemiology

Morton's neuroma is associated with a lesion of the toe nerve of the sole in the area of the head of the metatarsal bone. The nerve bundle may be under pressure from the transverse tarsal ligament.

In most cases, the common toe nerve in the third toe space of one limb is affected. The nerve in the other toe spaces of the foot is less frequently diagnosed.

Morton's neuroma is predominantly a "female" disease. Specialists attribute this fact to the regular use of high-heeled shoes by women. The pathology is treated by neurologists and orthopedic traumatologists. The average age of patients who consult doctors about Morton's neuroma is 45-55 years old.

The term "Morton's neuroma" was formed, thanks to the surname of the doctor who first described the painful pathology of the interfinger nerves and called it neuroma of the foot. By the way, "neuroma" in this case - not quite the correct name, since the syndrome has nothing to do with a benign tumor. Specialists point out that it would be more correct to call this syndrome metatarsalgia. In the International Classification of Diseases (ICD 10), Morton's neuroma is listed under G57.6 as a plantar nerve lesion. [2]

Causes of the morton's neuroma.

The most likely cause of Morton's neuroma is excessive and regular loading of the forefoot, which in turn is predominantly caused by the daily use of high-heeled shoes. Less common "culprits" are:

• uncomfortable, tight, ill-fitting shoes;
• impaired gait (also due to other pathological causes);
• overweight (additional load on the foot);
• occupational activities involving long periods of time on your feet.

Morton's neuroma often develops in patients who have a curvature of the foot, suffering from flat feet, flat-valgus deformity. [3]

A provocative role is played:

• all kinds of traumatic lesions of the distal part of the lower limb, including contusions, dislocations, fractures, as well as other injuries that are accompanied by damage, compression of the nerve;
• infectious processes such as tendovaginitis or bursitis of the joints of the foot, obliterating endarteritis or atherosclerosis, any tumor processes in the foot area.

Risk factors

The development of Morton's neuroma occurs under the influence of certain internal and external factors. Such factors can be:

• Overweight, which puts excessive strain on the lower extremities and contributes to the constant compression of nerve fibers in the foot area.
• Injuries to soft tissue and bone and joint mechanisms of the distal leg.
• Infections (especially of a chronic nature) affecting the musculoskeletal system.
• Foot curvature, flat feet.
• Frequent use of uncomfortable shoes (tight, curved, high heels).
• Tumor processes of the distal parts of the lower extremities.
• Excessive strain on the legs (sports, occupational overload, regular prolonged standing or walking).

Pathogenesis

The pathogenetic mechanisms of the development of Morton's neuroma are only partially studied, but experts have put forward several of the most probable assumptions on this issue. Thus, in the course of morphological study, it was found that at a certain point a thickening is formed on the intertarsal branch of the tibial nerve, which is not actually a neuroma, but a false neuroma, similar to that which occurs in the trunk of the median nerve above the area of compression in carpal tunnel syndrome. The pathologic process is most likely of ischemic origin.

Another starting factor may be repeated or multiple microtrauma or compression of the nerve between the third and fourth metatarsal bones. As a result of these pathological processes, the transverse intertarsal ligament of the foot experiences constant pressure, delaminates, and edema is formed. The median plantar nerve and nearby vessels are displaced and ischemia occurs.

According to studies, the average size of Morton's neuroma is 0.95-1.45 cm in length and 0.15-0.65 cm in width. The configuration of the pathologic element is oblong, spindle-shaped. [4]

Symptoms of the morton's neuroma.

Morton's neuroma can be asymptomatic, but only when its size does not exceed 5 mm. As the pathology progresses, "shooting", pulling pains appear in the area of the third and fourth toes of the foot. Pain is associated with physical impact, usually combined with numbness, allodynia. In the period of rest (e.g., night rest), symptomatology is most often absent.

In the absence of treatment at this stage of Morton's neuroma, the clinical picture gradually worsens. The pain is more frequent, intense, from aching to sharp, burning, begins to bother not only with physical activity, but also at rest. Often patients also talk about such a sensation as the feeling of the presence of a foreign particle in the shoe. Externally, the foot is not changed.

A sharp pain appears when trying to palpate the sore spot. Over time, sensory disorders worsen, up to loss of sensation in the area of the pathological focus.

Initial painful signs of Morton's neuroma usually occur in the background or immediately after physical activity (walking, running, prolonged standing):

• itching sensation, pinpoint, and after and spilling pain in the area of the third and fourth toe of the foot;
• tingling discomfort in the foot area, which increases with exertion;
• partial or complete loss of sensation in the toes of the foot;
• numbness, swelling of the distal lower extremity;
• sharp pain in the foot after exertion, with possible irradiation to other toes, heel, ankle.

The first symptoms often subside quickly, reappearing only after a few months. The problem is often eliminated by changing from high-heeled to flat-soled shoes.

Complications and consequences

If you ignore the treatment of Morton's neuroma, do not consult doctors, or do not fulfill orthopedic prescriptions, the disease process will steadily worsen. The risk of unfavorable consequences will increase:

• worsening pain syndrome, nighttime pain;
• limping, gait disturbances;
• the need to wear only special shoes (orthopedic shoes);
• curvature of the spinal column;
• Involvement of other joints in the pathological process, which is due to a violation of joint biomechanics;
• development of neuroses, depression, which is associated with constant pain and the inability to carry out normal daily activities.

Over time, the pain syndrome becomes more intense, and attacks become longer and more frequent. In neglected situations, conservative methods of therapy lose their effectiveness and surgical intervention has to be used, followed by a rather long rehabilitation period. [5]

Diagnostics of the morton's neuroma.

Diagnostic measures for suspected Morton's neuroma are relatively simple and are based primarily on the typical location of the painful focus (third to fourth toe). During palpatory squeezing of the third intertarsal space after about half a minute, the patient feels burning and numbness. Joint function is normal. Sensory disorders indicate the presence of nerve trunk damage.

The tests for Morton's neuroma are nonspecific but may be ordered as part of general clinical investigations.

Instrumental diagnosis is represented mainly by radiography, in some cases allowing the detection of bony patterning in the area of neuroma compression.

Despite the fact that ultrasound - ultrasound examination method - is commonly and actively used to assess the condition of soft tissues, it is rarely used in the diagnosis of peripheral nerve pathology.

MRI is also not always able to confirm the diagnosis of Morton's neuroma, and in some cases provides distorted information. Computed tomography is also insufficiently informative due to the absence of mineral deposits in the soft tissue neuroma.

Therapeutic and diagnostic blockade for Morton's neuroma is the most common method of reliable diagnosis. After it is performed in the area of the tarsal nerve, the pain syndrome regresses, which proves the presence of neuroma. [6]

Differential diagnosis

Differential diagnosis of Morton's neuroma is performed with the following pathologies:

• metatarsophalangeal synovitis;
• metatarsal stress fracture;
• metatarsophalangeal arthritis;
• bone neoplasms;
• Pathologies of the lumbar spinal column (pain can recoil in the area of localization of the tarsal spaces);
• osteonecrosis of the metatarsal head.

In addition to instrumental diagnostic methods, other subspecialists are involved for consultation as part of differentiation: neurologist, orthopedist, traumatologist, podologist. The final diagnosis of Morton's neuroma is made after all the necessary tests have been performed, and only then the appropriate therapeutic tactics are chosen.

Treatment of the morton's neuroma.

Most patients with Morton's neuroma are successfully treated conservatively, which primarily includes:

• unloading the foot;
• use of metatarsal pads, inserts, supinators, orthopedic insoles;
• use of a retrocapital stop (lowers pressure on the nerve when walking).

Various orthopedic devices normalize the load on the foot, balance the transverse arch, reduce the pressure of the bone and ligament apparatus on the affected nerve trunk, which helps to slow down the progression of the pathological process. At the same time, the inflammatory reaction subsides, pain disappears, foot function is restored, and gait improves.

In addition, it is possible to use complex compresses with local anesthetic and non-steroidal anti-inflammatory drugs, Dimexide, myorelaxants. In addition, manual therapy, injections of corticosteroids into the tarsal space from the outer part of the foot are also included. This approach has already led to the recovery of every third patient, and in others causes a permanent improvement in health.

If these methods are ineffective, surgeons are sought. [7]

Medications

To manage foot pain, patients with Morton's neuroma are prescribed nonsteroidal anti-inflammatory drugs, myorelaxants, analgesics, corticosteroid injections, [8], [9], sclerosing ethanol injections. [10] These medications are successful in relieving pain, relieving muscle spasms, and easing the course of the inflammatory response. The drugs can be used in the form of tablets, injections, external preparations (ointments, gels), suppositories.

The most popular tablet remedies are:

• Ketorolac (Ketanov, Ketocam, Ketofril) - taken in a single dose of 10 mg, and in case of repeated use - 10 mg up to four times a day, depending on the intensity of pain. The maximum daily dosage is 40 mg. The most probable side effects: problems with digestive organs, hematologic complications, renal dysfunction.
• Zaldiar (tramadol with acetaminophen) - prescribed by a doctor according to indications. The maximum dose per day is 8 tablets. The interval between doses is at least six hours. Side effects: headache, insomnia, allergies, nausea, hypoglycemic state.
• Ibuprofen - take 200-400 mg every 5 hours, as needed. Do not take more than six tablets during the day. Treatment should be completed within five days. With prolonged use, problems with the gastrointestinal tract are possible.
• Diclofenac - prescribe 75-150 mg per day, divided into 2-3 doses. Prolonged use may cause dizziness, ringing in the ears, nausea, abdominal bloating.

For intramuscular administration, it is administered predominantly:

• Meloxicam - administered intramuscularly 15 mg once a day, once or for 2-3 days. With prolonged use may develop dyspepsia, exacerbation of colitis, gastritis.
• Flexen - administered intramuscularly after preliminary dilution of the lyophilizate with solvent. The dose is 100-200 mg per day. After elimination of the acute painful process, it is recommended to switch from injections to capsules or suppositories. The maximum daily dose is 300 mg.

Spazgan, Baralgin, Trigan are suitable for single administration for pain relief.

External agents in the form of ointments, gels, creams are prescribed only in combination with other drugs of systemic action. Independent use of ointments is inappropriate and ineffective. The list of external preparations is approximately as follows:

• Indomethacin ointment is applied topically to the affected area up to four times a day, gently rubbing. It is optimal to apply the ointment every six hours.
• Ketoprofen - used 2-3 times a day, applying a thin layer with further careful rubbing. Can be used for phonophoresis. Do not use in case of hypersensitivity to ketoprofen or other non-steroidal anti-inflammatory drugs.
• Finalgon - after determining sensitivity and in the absence of allergic reaction apply to the affected area 2-3 times a day, using a special applicator. After application, hands should be washed thoroughly.

If the patient observes bed rest, then rectal suppositories with analgesic and anti-inflammatory action, for example, are excellent for him:

• Voltaren is used before bedtime, as well as during the day (as needed), one suppository. The optimal course of treatment is up to 4 days.
• Oki (ketoprofen) is prescribed by a doctor and used as a pain reliever. As a rule, one suppository (160 mg) is placed daily at bedtime.

Will massage help?

In many cases, massage treatments can help relieve pain and relax spasmed muscles - especially when performed by a professional massage therapist.

Patients with Morton's neuroma have their feet massaged daily for two weeks. This allows:

• to relax the tense muscles;
• relieve pain by reducing pressure on the affected nerve;
• to stop the inflammatory response from developing;
• will improve joint function.

It is important not to apply too much pressure on the heads of the bones of the foot during the massage. Rough and incorrect (inconsistent) pressure often leads to aggravation of the problem and increased pain.

A good effect is noted from the use of "cold" massaging. For the procedure take a small plastic bottle, pour ice cubes into it and massage (roll) the painful foot on the floor.

Surgical treatment

There are several options for surgical treatment of Morton's neuroma. The most common intervention using local anesthesia is the actual removal of the pathological focus. Since the neuroma is a hypertrophied part of the nerve cord, it is isolated and excised. Usually this operation leads to the elimination of pain syndrome, but in the foot area remains a small area of loss of sensation. All functions of the lower limb and foot are preserved, the recovery process lasts about one month.

Many specialists believe that this intervention is too radical in many cases, and often it may be sufficient to dissect (release) the transverse ligament between the metatarsal bones, which will free the nerve. An additional "plus" of this technique is the absence of residual sensory disturbances in the foot. More radical methods are only appropriate if release is ineffective.

Osteotomy of the fourth metatarsal bone, or nerve decompression surgery for Morton's neuroma is relatively rarely used. Nerve decompression is accomplished by displacing the head of the fourth metatarsal bone after osteotomy. The intervention is performed through a tiny incision or tissue puncture under the supervision of a radiologist. [11]

Prevention

Preventive measures to prevent the development of Morton's neuroma are quite simple and include the following points:

• wearing comfortable shoes, not too narrow, properly sized, without high heels;
• Comprehensive and timely treatment of any foot pathology, with the use of drug therapy, physiotherapy, physical therapy, physical therapy, orthopedic devices as indicated;
• avoiding overload and hypothermia of the lower extremities;
• weight control;
• prevention of curvature of the feet and toes;
• injury prevention.

If it was not possible to avoid increased stress on the feet, it is recommended to immediately perform a relaxing massage of the toes and the entire foot, make a contrast foot bath. People suffering from flat feet or other curvatures of the foot should consult a specialist about the selection of orthopedic shoes or special devices (insoles, corrective inserts, supinators).

Forecast

The prognosis can be favorable, if the patient timely turns to doctors - at the first painful signs, when there is still an opportunity to stop the pathological process and prevent the development of irreversible changes in the tissues.

Later treatment is usually more complicated. It is often necessary to seek the help of surgeons to prevent widespread aggravation of neurological function and the appearance of pronounced limitations on a person's motor abilities.

In advanced cases, this can lead to persistent motor impairment as a result of severe pain. The patient, in fact, becomes disabled and requires urgent surgical intervention.

There is only one conclusion: Morton's neuroma of the foot is successfully treated conservatively at the initial stage, so if the first signs appear, you should consult a doctor without delay. A neglected disease is also amenable to treatment, but more complicated and complex: surgery may be required.