The tarsal tunnel syndrome is one of the nerve-constriction / nerve compression syndromes. A distinction is made between front and rear tarsal tunnel syndrome. In the anterior, the N. fibularis profundus is affected. The posterior is a syndrome in which the tibial nerve is compressed in the so-called tarsal tunnel.
Both are derived from the sciatic nerve ("sciatic nerve ").
More often, the rear tarsal tunnel syndrome occurs. The tibial nerve runs along the posterior leg to the side of the foot down to the sole of the foot. It provides motor muscles of the calf and foot and is thus responsible, among other things for the toe tip. Sensitive, he provides a part of the calf and the sole of the foot.
It can be narrowed in its course behind the medial malleolus. Here is the so-called Tarsaltunnel, which is bounded from the inside bony and is covered by a band from the outside, the flexor retinaculum or ligamentum laciniatum.
The anterior tarsal tunnel syndrome is a nerve constriction syndrome involving the deep fibular nerve (sometimes obsolete, sometimes called the peroneal nerve). A synonym is therefore also "fibularis syndrome".
The N. fibularis profundus is a nerve branch of the N. fibularis communis, which in turn is a nerve part (Fibularisanteil) of the N. sciatic nerve. This splits above the popliteal fossa into 2 nerves dividing: common fibular nerve and tibial nerve. In addition to the N. fibularis profundus, the N. fibularis superficialis also develops from the Fibularis portion, namely, the two nerve branches separate in the region of the Fibulaköpfchen, more precisely in the M. fibularis longus. For the symptomatology, however, the nerve branch of the N. fibularis profundus is mainly significant.
The cause of the anterior tarsal tunnel syndrome is nerve compression in the region of the ankle, where the nerve is located underneath a ligamentous structure, the retinaculum extensorum inferius (also known as the ligamentum cruciforme in the literature). In addition to the retinaculum, a muscular structure, the M. extensor hallucis brevis, can lead to nerve compression. The constriction can be provoked by the frequent wearing of high heels. Also ski boots and mountaineering shoes can aggravate the symptoms. The common cause, as with many other nerve dysphagia syndromes, is the presence of tendonitis, as the affected region swells at the expense of the deep fibular nerve. But even after injuries, the presence of a ganglion (= overbone, abnormal tissue change on joint capsules or tendon sheaths) or diabetes mellitus can increase the risk for a front tarsal tunnel syndrome enormously. In the end, however, the state of pregnancy or a chronic circulatory disorder may also compress the N. profundus.
The anterior tarsal tunnel syndrome can be conservatively treated using lymphatic drainage, local infiltration of steroids and local anesthetic, ointments and insoles.
Failure to respond to conservative treatment usually involves surgery.
The posterior tarsal tunnel syndrome, on the other hand, affects the tibial nerve and manifests at the inner ankle region. The tibial nerve, the tibial component of the sciatic nerve, runs down to the foot in the depths of the calf muscles, the deep flexor lodge. There he pulls on the inside of the ankle through the medial or posterior tarsal tunnel (= Canalis malleolaris) on the sole of the foot. When passing through the tarsal tunnel, the tibial nerve is separated into the two nerve branches, the N. plantares lateralis and the N. plantares medialis.
The passage through the tarsal tunnel is a relevant constriction, so that nerve tuberculosis of the tibial nerve here is very likely. The posterior tarsal tunnel syndrome is generally more common than the anterior tarsal tunnel syndrome.
The anatomical constriction is due to the compact position of various structures. Of particular note is the retinaculum musculi flexorum, a band-like structure between the medial calcaneus and the medial malleolus. As with the anterior tarsal tunnel syndrome, injuries, fractures, ganglion, metabolic diseases (diabetes mellitus, gout, hypothyroidism, etc.) or tendonitis can trigger a space-occupying process leading to nerve compression. A risk factor of the posterior tarsal tunnel syndrome is also the mechanical overload caused by long jogging ("joggers foot").
Decisive for the diagnosis are first and foremost the information given by the patient during the anamnesis (survey by the physician) and the clinical examination. This is often a pressure pain behind the affected inner ankle, also often the Hoffmann-Tinel sign is positive. To test this sign, the examiner taps the course of the nerves and can thereby trigger electrifying pain in the patient's area of discomfort.
By means of electrophysiological methods, the nerve conduction velocity of the tibial nerve can be measured, which is reduced in a tarsal tunnel syndrome in this area. Testing the sweat secretion on the sole of the foot using the ninhydrin test can also be enlightening as it is often reduced in tarsal tunnel syndrome.
MRI (Magnetic Resonance Imaging) is characterized by the decisive advantage that it can display soft tissue, such as ligaments and cartilage, well. This is particularly useful in ankle diagnostics, where torn ligaments or overstretching and inflammation are particularly common.
Magnetic Resonance Imaging is based on the movement of atoms, and since our body is largely made up of water molecules, we mainly use the movement of these for imaging. This also explains why the lungs or bones are not very well on MRI. There are not many water molecules in these tissues.
The symptoms of anterior tarsal tunnel syndrome manifest as a painful sensation on the instep and above the ankle. This pain can occur both at rest and at night as well as under stress with radiation into the calf. Characteristic is also the pressure pain. In addition to pain, paresthesias occur in the area between the first two toes, as the deep fibular nerve is responsible for the sensory supply (lat. Interdigital space I + II). To a certain extent, it can even lead to the weakening of the toe extensor muscles by compression of the motor nerve parts. This causes sufferers problems walking.
The symptoms of a rear tarsal tunnel syndrome are very variable. In principle, there may be failures of the motor or the sensitive parts. Patients often complain of a numbness in the sole of the foot because this region is affected by the Nn. plantares is supplied. Next paraesthesia is the tingling in the toes. Pain occurs in the posterior tarsal tunnel syndrome, especially on the underside of the foot and the inner malleolus. The pain character can be from burning and pulling to stabbing. Both at rest and under stress, the pain is felt. Partly it is reported about a sleepy nocturnal pain. An isolated pain on the heel may be an indication that a special nerve branch (calcaneus) supplying the heel region is affected. Long-lasting nerve compression may even lead to paralysis (= paresis) of the foot muscles. In most cases, the symptoms increase after prolonged standing or walking.
In a tarsal tunnel syndrome, both feet do not often become numb.
Very often a tarsal tunnel syndrome occurs in long units on the crosstrainer. Especially in combination with knees both feet become numb.
In this case, in almost all cases, a pad restoration after a treadmill analysis is sufficient to eliminate all symptoms.
At the beginning the attempt of a conservative (non-operative) therapy is usually sought. Here are used:
However, contrary to conventional assumptions, the latter have proven rather unhelpful or even unhelpful.
If the symptoms persist despite such treatment, there is the potential for surgery where decompression of the tibial nerve is the goal. For this purpose, the flexor retinaculum spanning the tarsal tunnel is split, giving the nerve more space again.
The purpose of taping is to support the function of muscular structures and joints and to ensure better stability. Due to their elastic nature, there is no restriction of movement.
For the conservative treatment of tarsal tunneling, taping is being used more and more frequently.
The taping of an ankle can relieve this and the body, for example, better conditions for healing of a tendon sheath inflammation in the sense of a faster swelling and the concomitant decompression of the N. fibularis profundus or tibial nerve. The tape is applied along the course of the affected structures and thus also depends on whether it is a front or rear tarsal tunnel syndrome. The tape should only be applied by trained professionals for optimum effect development.
The wearing of insoles can be both a first conservative therapeutic approach, as well as the aftercare after an operation, including the post-treatment in addition to the relieving footwear and physiotherapy and the targeted training of mobility.
The use of inserts is especially useful if the cause of the tarsal tunnel syndrome in a Fußfehlhaltung as the "kink Senkfuß" is. By wearing specially shaped inserts, the foot posture can be optimized a bit, as the insert attempts to mimic the normal position of the foot. In most cases, the inserts on the medial, ie inner foot side have a supporting arch, which can support the possibly weak arch of the foot. The aim is therefore to improve the bearing surface so that pressure and forces can be distributed more uniformly and more gently.
In principle, the symptoms are first tried to be alleviated by the conservative variant. If there is no improvement after about 8 weeks, or if the symptoms return frequently after improvement, surgery should be considered. In the anterior tarsal tunnel syndrome conservative therapy helps less often, so often the indication for surgery is made here. The retinaculum extensorum inferius (ligamentum cruciforme) is severed in order to counteract the compression due to space-occupying processes.
Even in the case of the posterior tarsal tunnel syndrome, which occurs much more frequently, failure to respond to conservative therapy is a reason for surgery. To rule out the suspicion of a ganglion or even a nerve tumor, a clarification by an MRI or neurosonography is necessary, since in this case a simple separation of the band structures for relief in the long term is not a solution.
The operation generally has two objectives: first, to repair the constriction in the area of the tarsal tunnel and, secondly, to ensure that the two nerve branches (plantar medial and lateral lateral branches) pass through the rough sole of the foot to the underside of the foot. Today, the procedure can be minimally invasive under general anesthesia. First of all, it is important to orient yourself correctly in order to optimally choose the cut. In this case, palpation of the pulse of the posterior tibial artery may be helpful as it passes through the tarsal tunnel together with the tibial nerve and tendon parts. After a skin incision, the site to be operated on is uncovered and the flexor retinaculum flexorum pedis, a band-like structure between the medial heel bone and the inner malleolus, is split. This leads to the relief and cancellation of the compression. As mentioned, but also the two Nn. plantares may be relieved. They run separately on the sole of the foot in a muscle fascia of the abductor hallucis muscle. In order to counteract space-occupying processes here, the fascia can be split into corresponding areas. Only when the exposure of the nerve is over a longer distance can the desired decompression occur.
Gypsum should not be applied after the operation as both the N. fibularis profundus and the N. tibialis heal better and faster when they can glide. If mobility is restricted, scar tissue will be scarred. In addition, the muscle press for venous thrombosis prophylaxis must be able to work again. In general, it is therefore recommended to protect the foot while wearing walking aids for 10 days, but still to move it gently and carefully.
The operation has been proven to have good success rates, so that sufferers are completely free of pain afterwards. Only mild sensory disturbances can persist for a few days after surgery.
The most important thing in a tarsal tunnel operation is the previous and the exact diagnosis. There are many causes that may be responsible for foot pain and therefore, measurement of nerve conduction or other neurological evidence suggests that impairment of the nerve is detected before any surgery is performed. The risk of a tarsal tunnel operation lies mainly in the fact that the operating area is directly burdened by the occurrence of very high. This must be mitigated in the first few days necessarily by Unterarmgehstützen or the like.
In addition, there is a risk of scarring of the operating area, which would lead to a renewed surgical constriction of the nerve. In addition, both nerve, artery and vein pass through the tarsal tunnel. Errors during surgery may cause injury to these vessels and bleeding.
The most important thing is to protect the sole of the foot and forefoot for the first few days after surgery. Of course, one should not refrain completely from any movements and running for longer than a few days, because otherwise the risk of leg vein thrombosis is too high. So most patients will receive some blood thinners for a few days to reduce this risk.
In addition, there is always the danger that the muscles will be greatly reduced if certain groups are not used for a long time. However, the exact duration of the cure can not be predicted specifically because it is highly dependent on the ability of the nerve to regenerate in the individual. It can take up to six months and may require a second surgery, but may take much shorter depending on the conditions.
The inability to work after surgery on the tarsal tunnel also depends entirely on the patient's recovery. Usually it comes to a sick leave of four to six weeks. It depends entirely on the circumstances of the operation. Whether the left or the right foot is affected can affect the permission to drive by car.
If an unwanted scarring has occurred, it may be necessary to have surgery again, which also extends the sick leave. However, if one keeps to the rest and rest periods prescribed by the doctor, in most cases it will be possible to return to work after about six weeks.
There are a few exercises that can help to strengthen the foot muscles and relieve the nerve compression or prevent their recurrence. However, the exercises should only be performed if the resulting pain is not increased too much. It is important to perform the exercises regularly over a period of time, so that they are really effective. Most of these exercises, however, can also be wonderfully incorporated into everyday life and always perform in between.
One of these exercises is called "swing". This is about putting barefoot on tiptoe and "rocking" on their heels from there. This should be done slowly, controlled and performed several times at a time.
In another exercise, lift your toes with a pencil or towel lying on the floor. In addition, one can with exercises to ensure that the calf muscles are relaxed by stretching. Thus, under stress, the focus is not on the ankle, but is intercepted by the calf muscles. There are all possible strategies for this; One of the possibilities is to use a towel to put a noose around his forefoot and to pull on this noose slowly and in a controlled manner so that the toes point upwards.
Bandages, which are worn on joints, can in principle increase the stability and thus ensure that complaints tend to go back and pain is reduced by stress. Even with a tarsal tunnel syndrome, a bandage and the resulting stability can be of great benefit. Even basic malpositions are restricted or prevented by the bandaging of a joint. Because even bad postures can cause nerve compression. Similarly, one can compensate for such incorrect posture with deposits that shift the burden on the outside of the foot, rather than promoting the burden of the nerve.
Pregnancy brings with it many changes in the body. On the one hand, the hormonal balance changes the tissues of a woman in order to prepare her for childbirth. Bands relax to widen the pelvis. However, this naturally also loosens all other ligaments of the body. As a result, the stability in all possible joints can decrease and it can be easier to injury.
Another change during pregnancy is the increase in water retention in the body. Up to 6-7 liters more water than usual can be found in the woman's body. This increased water causes edema to form in the body. This irritates nerves and women often feel that their arms or legs have "fallen asleep". Of course, this nerve irritation can also lead to a tarsal tunnel syndrome. Of course, the ankle and foot naturally suffer from gravity due to the amount of water in the body
The thyroid gland is an important organ of our body, which is responsible for much of the hormone balance. Thyroid hormones regulate our metabolism and much more. Hyperthyroidism or hypofunction may result in numerous symptoms.
In addition to palpitations / bradycardia (slowed heartbeat), restlessness / listlessness and weight loss / gain can also be joints and nerves affected. The nerve sheaths (called endo- and perineurium) can be negatively affected by a defective thyroid hormone concentration in the blood. This can cause the tarsal tunnel syndrome.