The near-nerve sensory nerve conduction in tarsal tunnel syndrome.

The near-nerve sensory nerve conduction in the medial and lateral plantar nerves was studied in 25 cases of tarsal tunnel syndrome. Sensory nerve conduction was abnormal in 24 cases (96%) The most common abnormalities were slow nerve conduction velocities and dispersion phenomenon (prolonged duration of compound nerve action potentials). These two electrophysiological abnormalities are indicative of a focal segmental demyelination as the primary pathological process in tarsal tunnel syndrome.     

The tarsal tunnel syndrome

Tarsal tunnel syndrome is relatively rare and the diagnosis may be difficult even though the etiologies for the syndrome are multiple. The symptoms are often vague but are usually burning pain and paresthesias in the toes and soles of the feet with nocturnal exacerbations. The physical examination may elicit a sensory deficit over the cutaneous distribution of the median and/or lateral plantar nerve. There may also be tenderness over the flexor retinaculum. Electrodiagnosis, especially with the addition of the orthodromic compound nerve action potential latency technique, is essential to confirm the diagnosis. The findings may be confined to the distribution of either the medial or lateral plantar nerves and, thus, both distal latencies must be determined. Surgical decompression of the tarsal tunnel has usually proven to be helpful in those patients who do not respond to conservative treatment.     

The anterior tarsal tunnel syndrome

Summary The anterior tarsal tunnel syndrome, first described in 1968 by Marinacci, is characterized by a compression of the deep peroneal nerve under the inferior extensor retinaculum. The patients complaint of pains on the dorsum of the foot, especially at night. Clinically result sensory deficits in the involved area between the first and second toes as well as paresis and atrophy of the extensor digitorum brevis. The distal latency of the deep peroneal nerve is increased, the EMG shows active and chronic denervation of the extensor digitorum brevis. In cases with partial anterior tarsal tunnel syndrome only the motoric branch to the extensor digitorum brevis or only the sensory branch of the deep peroneal nerve after the division under the inferior extensor retinaculum is compressed. Two cases with complete and one with partial anterior tarsal tunnel syndrome are presented, etiology, symptomatology, differential diagnosis and therapeutic possibilities are discussed.

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Zusammenfassung Das 1968 erstmals von Marinacci beschriebene vordere Tarsaltunnelsyndrom besteht in einer Kompression des N. peronaeus profundus unter dem Ligamentum cruciatum. Subjektiv werden heftige, vor allem nachts auftretende Schmerzen im Fußrückenbereich geklagt. Klinisch resultieren sensible Ausfallserscheinungen im entsprechenden Hautareal zwischen der ersten und zweiten Zehe sowie Parese und Atrophie des M. extensor digitorum brevis. Elektroneurographisch findet sich eine erhöhte distale motorische Latenz des N. peronaeus profundus, elektromyographisch ist aktive und chronische Denervierung im M. extensor digitorum brevis nachweisbar. In Fällen mit partiellem vorderen Tarsaltunnelsyndrom wird entweder nur der motorische Ast zum M. extensor digitorum brevis oder nur der sensible Anteil des N. peronaeus profundus nach der Teilung unter dem Ligamentum cruciatum komprimiert. Zwei Fälle mit vollständigem sowie ein Fall mit partiellem vorderen Tarsaltunnelsyndrom werden vorgestellt; Ätiologie, Symptomatologie, Differentialdiagnose und therapeutische Möglichkeiten werden erörtert.

     

The tarsal tunnel syndrome in hypothyroidism.

Nine patients with myxoedema and carpal tunnel syndrome have been studied clinically and electrophysiologically to determine the presence or absence of the tarsal tunnel syndrome. Four patients had electrophysiological evidence of the tarsal tunnel syndrome, three of whom were mildly symptomatic. This would suggest that the tarsal tunnel syndrome is frequently encountered in myxoedema in association with the carpal tunnel syndrome.     

Not tarsal tunnel syndrome: a malignant "Triton" tumour of the tibial nerve.

A 23 year old male patient presented with a venous thrombosis in the right calf. This was followed by symptoms, signs and electromyographic findings suggestive of a tarsal tunnel syndrome. Symptoms were briefly relieved by surgical division of the flexor retinaculum. Subsequently, patient developed swelling in the calf and was found to have a malignant ("Triton") tumour of the tibial nerve and required above knee amputation. In the absence of obvious foot or ankle deformity, caution should be exercised in making the diagnosis of tarsal tunnel syndrome.     

An electrophysiological severity scale in tarsal tunnel syndrome

OBJECTIVE: To propose a neurophysiological classification of tarsal tunnel syndrome. MATERIAL AND METHODS: We retrospectively reviewed the medical records of two electromyography laboratories. Case inclusion criteria were based on clinical parameters. Motor conduction velocity, distal motor latency (DML), sensory conduction velocity (SCV) and sensory action potential (SAP) from big toe (T1) and from fifth toe (T5) to medial malleolus were measured in the medial and plantar nerves. When SCVs of T1 and T5 were normal, we considered the difference in T1 SCV between affected and unaffected side and in T1 SCV of the affected side with sural nerve distal SCV. Feet with TTS were classified in six electrophysiological classes: 0, normal SCV and DML; 1, normal absolute SCV with abnormal comparative tests; 2, slowing of T1 and T5 SCV and normal DML; 3, slowing of SCV and DML; 4, absence of T1 and T5 SAPs and abnormal DML; 5, absence of sensory and motor response. RESULTS: A total of 111 feet belonging to 96 patients (27 men, 69 women; mean age 49.6 years) were diagnosed with TTS. T1 and T5 SCV were abnormal in 82 and 73% of cases, respectively, and comparative tests were abnormal in a further 7% of cases. DML was abnormal in 82 feet (73.9%). Eight feet (7%) were without neurographic abnormalities. The distribution of feet in neurophysiological classes was: stage 0, 7%; stage 1, 9%; stage 2, 10%; stage 3, 39%; stage 4, 32%; stage 5, 3%. Higher clinical scores coincided with higher neurographic classes. CONCLUSION: The progression of neurographic abnormalities in TTS reflects the relation between SCV and DML, and between neurographic values and clinical severity. The scale assigns severity classes in a reliable and non-arbitrary way. This classification can easily be used by electrophysiological laboratories with their own electrophysiological techniques and normal values.     

Nerve ultrasound in electrophysiologically verified tarsal tunnel syndrome

Introduction: Tarsal tunnel syndrome (TTS) arises from tibial nerve damage under the flexor retinaculum of the fibro‐osseus tunnel at the medial malleolus. It is notoriously difficult to diagnose, as many other foot pathologies result in a similar clinical picture. We examined the additional value of nerve ultrasound in patients with tarsal tunnel syndrome confirmed by nerve conduction. Methods: We performed a retrospective analysis of nerve ultrasound changes in electrophysiologically confirmed TTS spanning our records from 2007 to 2015. Results: Nine feet with TTS were identified, all of which showed abnormal nerve ultrasound findings, which in 6 feet, led to identification of the underlying cause. Conclusions: This study shows that nerve ultrasound is abnormal in all cases of electrophysiologically verified TTS. The pattern of nerve abnormality is varied. This, and the fact that in the majority of patients causation was identified, suggests nerve ultrasound should form part of standard work‐up for TTS. Muscle Nerve 53 : 906–912, 2016     

Tibial nerve entrapment in the popliteal fossa

Details are presented of nine cases of tibial nerve entrapment by the tendinous arch of origin of the soleus muscle. The diagnosis was confirmed by surgical exploration of the popliteal fossa in six patients, who recovered fully after division of the soleus arch, whereas the other three improved spontaneously. This condition can be distinguished clinically from tibial nerve compression at the ankle, and from S1 radiculopathy, by the presence of severe pain and tenderness and a positive Tinel sign in the popliteal fossa, and by electrodiagnostic studies.     

Electrophysiological improvement following decompression surgery in tarsal tunnel syndrome

Plantar nerve conduction studies 14 months to 3.5 years after decompression surgery in 3 cases of tarsal tunnel syndrome showed an improvement in motor conduction as well as in sensory nerve conduction. This electrophysiological improvement was associated with clinical improvement. However, minor abnormalities still existed in sensory nerve conduction in all 3 cases.     

Pressure perception in the normal lower extremity and in the tarsal tunnel syndrome

For quantitative sensory testing to be useful for the management of peripheral nerve problems, a normative database must be developed. The Pressure-Specified Sensory Device™ (PSSD), a handheld instrument whose hemispherical metal probe tips are connected via a force transducer to a computer, has been found reliable and valid for the upper extremity. In the present study, the PSSD was used to measure the cutaneous pressure threshold at four lower extremity sites in 34 normal adults and in 22 patients with tarsal tunnel syndrome (6 bilateral). Each of the 28 limbs that was symptomatic for tarsal tunnel syndrome had a cutaneous pressure threshold greater than the 99% confidence limit of the age-matched controls (≤ 45 years, > 45 years of age). Screening for tarsal tunnel syndrome can be done utilizing the measurement of the two-point static-touch thresholds for pressure and distance. © 1996 John Wiley & Sons, Inc.     

Focal conduction block in a case of tarsal tunnel syndrome

We report a case of tarsal tunnel syndrome (TTS) with focal conduction block across the tarsal tunnel (TT). A 46‐year‐old woman had pain in the left foot, sensory loss on the plantar surface, and positive Tinel sign over the TT. TTS was confirmed by magnetic resonance imaging (MRI) scan and surgery. Motor nerve conduction studies showed focal conduction block across the TT. Conduction block has rarely been reported in TTS. In this case, conduction block provides evidence for focal demyelination as the primary pathological process in TTS. Muscle Nerve, 2010     

Clinical and electrophysiological findings and follow-up in tarsal tunnel syndrome

The authors report clinical and electrophysiological findings in 59 patients with tarsal tunnel syndrome (TTS) and follow-up in 23 of them. The entrapment was prevalent in females; was bilateral in 6 patients and involved medial plantar in 7 and lateral plantar nerves in two cases. Eleven presented with other nerve entrapment syndromes or focal mononeuropathies, due to hereditary neuropathy with liability to pressure palsy or systemic diseases. The other 48 subjects had TTS without any other related entrapment syndromes: 23 were idiopathic cases, 13 had a history of local trauma, 3 had systemic diseases and the others had external or intrinsic compressions. The most frequent symptoms were paraesthesia or dysaesthesia (86% of feet) and pain (55%). Hypoaesthesia of the sole and weakness of toe flexion were evident in 74% and 22% of feet, respectively. Absence of sensory action potential or slowing of sensory conduction velocity (SCV) of the plantar nerves were present in 77% of feet; significant differences of SCV between affected and unaffected plantar nerves and/or between distal sural and plantar nerves were evident in 14%. Abnormalities of plantar SCV were therefore absent in only 9% of feet. Distal motor latency was delayed in 55% and electromyography showed neurogenic changes in 45% of sole muscles. Five cases (6 feet) underwent surgery with excellent or good results in 5, 4 of them also showing improvement in distal conduction of the plantar nerves. Nine were treated with local steroid injections, with good results shown in 6 patients. Nine other patients who did not receive any therapy showed a disappearance of symptoms or good outcome in 6 cases. The subjects with poor therapeutic results had S1 radiculopathy or systemic diseases. The authors underline that patients with connective tissue diseases should not be treated by surgical decompression because they may have subclinical neuropathy. Some subjects with idiopathic or trauma-induced TTS recover spontaneously. Surgical release should be limited to cases with space-occupying lesions and when conservative treatments fail.     

Post-traumatic tarsal tunnel syndrome: interest of muscular MRI

INTRODUCTION: Tarsal tunnel syndrome is a compressive neuropathy of the tibial nerve with multiple causes. This syndrome is difficult to diagnose and can be missed because of its subjective symptomatology. OBSERVATION: In our patient, suspected post-traumatic tarsal tunnel syndrome was confirmed at MRI. This case highlights muscle signal anomalies caused by their denervation in the tibial nerve territory. CONCLUSION: MRI can provide supplementary information to the electromyography (EMG) and contribute to positive and etiologic diagnosis of peripheral nerve lesions.     

The tarsal tunnel syndrome after a proximal lesion.

Three patients in whom the first symptoms of the tarsal tunnel syndrome (TTS) emerged after an acute event proximal to but not affecting the ankle are described. These patients suggest that a pre-existing asymptomatic TTS may become manifest after a mechanism akin to that described in the "double crush" syndrome.