Tarsal Tunnel Tarsal Tunnel SyndromeSyndromeBetterBetter - vulnerabilities of distal - vulnerabilities of distal tibial & plantar nerves at the ankle tibial & plantar nerves at the ankle and footand foot

objectivesobjectives Understand the ‘tarsal tunnel concept’Understand the ‘tarsal tunnel concept’ Know the EDX for TTSKnow the EDX for TTS To appreciate the realities of RRSTo appreciate the realities of RRS

Tarsal tunnel syndrome Tarsal tunnel syndrome (TTS)(TTS)

TTS – TTS – “ a complex of symptoms resulting “ a complex of symptoms resulting from compression of the tibial nerve or of from compression of the tibial nerve or of the plantar nerves in the tarsal tunnel, the plantar nerves in the tarsal tunnel, with pain, numbness and tingling with pain, numbness and tingling paresthesias of the sole of the foot”paresthesias of the sole of the foot”

From: Dorland’s Medical Dictionary 28From: Dorland’s Medical Dictionary 28 thth editionedition

Tarsal tunnel SyndromeTarsal tunnel Syndrome This is a RARE conditionThis is a RARE condition Most reports – local trauma to distal tibial Most reports – local trauma to distal tibial

nerve rather than ‘idiopathic TTS’nerve rather than ‘idiopathic TTS’ If truly an ‘idiopathic’If truly an ‘idiopathic’

Must be compromised under laciniatum Must be compromised under laciniatum ligament (retinaculum musculorumm flexorum ligament (retinaculum musculorumm flexorum

pedis)pedis)Or entrapment in abductor hallucisOr entrapment in abductor hallucis

ligamentligament laciniate ligamentlaciniate ligament Or LacinatumOr Lacinatum Or retinaculum muscculum flexorum Or retinaculum muscculum flexorum

pedispedis

This is ‘tarsal tunnel syndrome’This is ‘tarsal tunnel syndrome’

CMAP AMPLITUDE AND CMAP AMPLITUDE AND DURATION – IMPORTANT!DURATION – IMPORTANT!

Compare amplitude when stimulating Compare amplitude when stimulating proximal and distal to TTproximal and distal to TT

Side-to-side amplitudes = 20% Side-to-side amplitudes = 20% Latency is helpful –but not the only Latency is helpful –but not the only

parameter for diagnosisparameter for diagnosis

Foot – locate intrinsic Foot – locate intrinsic musclesmuscles

Abductor hallicus – 1 cm below navicular Abductor hallicus – 1 cm below navicular tubercletubercle

Abductor dig V pedis – below the lateral Abductor dig V pedis – below the lateral malleolus at junction of normal and sole malleolus at junction of normal and sole skinskin

Note best placement of recordingelectrode

Stimulate distal to tarsal ligament

Ankle entrapmentsAnkle entrapments Tarsal tunnel Syndrome - idiopathicTarsal tunnel Syndrome - idiopathic

This is This is overdiagnosed!overdiagnosed! Could be lateral plantar nerve in abd hallicusCould be lateral plantar nerve in abd hallicus Or distal tibial nerve under lanciniatum ligamentOr distal tibial nerve under lanciniatum ligament

Frequently present as compromise in diabetic Frequently present as compromise in diabetic peripheral neuropathyperipheral neuropathy

EDXEDX Motor latency – medial plantar n <5.5 ms; lat pl n - <6 msMotor latency – medial plantar n <5.5 ms; lat pl n - <6 ms Trans-tarsal amplitude and latency similar to sural – Trans-tarsal amplitude and latency similar to sural –

amplitude reduced and latency prolongedamplitude reduced and latency prolonged

Lateral plantar nerve Lateral plantar nerve entrapmententrapment

More frequently seen in diabetic peripheral neuropathyMore frequently seen in diabetic peripheral neuropathyCNAP will be reduced or absent with CNAP will be reduced or absent with

stimulation at sole of foot (Lat Pl N)stimulation at sole of foot (Lat Pl N)CMAP of abd dig min pedis will be smallerCMAP of abd dig min pedis will be smaller

Needle EMG abnormalities in abd dig V ped and lateral Needle EMG abnormalities in abd dig V ped and lateral interosseus muscles. interosseus muscles. Do not accept notion that Do not accept notion that abnormal irritability is present in normal foot abnormal irritability is present in normal foot intrinsic muscles intrinsic muscles

(In 45% of patients lateral Plantar nerve will give (In 45% of patients lateral Plantar nerve will give branch to anterior plantar fascia branch to anterior plantar fascia ergo. Resistent plantar ergo. Resistent plantar fasciitisfasciitis

Tarsal tunnel valuesTarsal tunnel values Medial plantar nerve - >6 ms Medial plantar nerve - >6 ms Lateral plantar nerve - >7 msLateral plantar nerve - >7 ms

NB. Amplitudes and trans-tarsal latencies NB. Amplitudes and trans-tarsal latencies are critical for diagnosisare critical for diagnosis

Compare contralateral values (nl = +/- 20%Compare contralateral values (nl = +/- 20%

Trans-tarsal technique Trans-tarsal technique Medial plantar nerveMedial plantar nerve

Amplitudes similar to suralAmplitudes similar to sural Lateral plantar nerveLateral plantar nerve

Amplitudes similar to suralAmplitudes similar to sural

NB. This is a MIXED nerve action potentialNB. This is a MIXED nerve action potential

Duration is the key

Trans tarsal mixed N Trans tarsal mixed N valuesvalues

Note the amplitude and durationNote the amplitude and duration Latency can be converted to CV (nl >35 Latency can be converted to CV (nl >35

M/sec)M/sec) NB. Comparable to sural nerve valuesNB. Comparable to sural nerve values

Tarsal tunnel Tarsal tunnel isis a a syndrome!syndrome!

Definition – comparable with CTS if Definition – comparable with CTS if compromise is under lancinatum compromise is under lancinatum ligament – this is rare!ligament – this is rare!

Could occur if underlying nerve is ‘sick’ Could occur if underlying nerve is ‘sick’ as in peripheral neuropathyas in peripheral neuropathy

Many cases are 2d to trauma at ankle Many cases are 2d to trauma at ankle Ergo. Ergo. NOT really tarsal tunnel syndromeNOT really tarsal tunnel syndrome

Tarsal tunnel –Tarsal tunnel –bottom linebottom line

This is a This is a rarerare disorder but it can be DX disorder but it can be DX ‘‘Idiopathic’ is rare Idiopathic’ is rare

Must verify with mixed – trans-tarsal Must verify with mixed – trans-tarsal abnormal values – best test (consensus)abnormal values – best test (consensus)

Must do needle EMG on intrinsic foot Must do needle EMG on intrinsic foot muscles (caution!- end plate areas)muscles (caution!- end plate areas)

It is common – only – in patients with It is common – only – in patients with underlying diabetic polyneuropathy underlying diabetic polyneuropathy

referencesreferences Kerr & Frey: MR imaging in tarsal tunnel. J Computer Kerr & Frey: MR imaging in tarsal tunnel. J Computer

Assisted Tomography. 1991. 15:280Assisted Tomography. 1991. 15:280 Kinoshita, M et al: The dorsiflexion-eversion test for Kinoshita, M et al: The dorsiflexion-eversion test for

diagnosis of tarsal tunnel syndrome.2001.83A:1835.diagnosis of tarsal tunnel syndrome.2001.83A:1835. Mondelli, M et al: an electrophysiologic severity scale in Mondelli, M et al: an electrophysiologic severity scale in

tarsal tunnel syndrome.Acta. Neurologica tarsal tunnel syndrome.Acta. Neurologica Scandinavica.2004.109:284Scandinavica.2004.109:284

Oh, S et al: Electrophysiologic improvement following Oh, S et al: Electrophysiologic improvement following decrompression surgery in tarsal tunnel syndrome. decrompression surgery in tarsal tunnel syndrome. Muscle & Nerve 1991.14:407Muscle & Nerve 1991.14:407

Ward,P & Porter, M: Tarsal tunnel: a study of the Ward,P & Porter, M: Tarsal tunnel: a study of the clinical and neurophysiologic results of decompression. clinical and neurophysiologic results of decompression. J Royal Coll of Surg of Edinburgh.1998.43:35.J Royal Coll of Surg of Edinburgh.1998.43:35.

referencesreferences Dellon A et al: Variations in origin of medial calcaneal Dellon A et al: Variations in origin of medial calcaneal

nerve. J Am Podiatric Med Assn. 2002.92:97nerve. J Am Podiatric Med Assn. 2002.92:97 Dumitru, D et al: SSEP of medial & lateral plantar & Dumitru, D et al: SSEP of medial & lateral plantar &

calcaneal nerves. Muscle & Nerve.1991.14:665calcaneal nerves. Muscle & Nerve.1991.14:665 Felsenthal, G et al: Across tarsal tunnel motor nerve Felsenthal, G et al: Across tarsal tunnel motor nerve

consuction technique. Arch PM&R 1992.73:64consuction technique. Arch PM&R 1992.73:64 Galardi, G et al: Electrophysiologic studies in Tarsal Galardi, G et al: Electrophysiologic studies in Tarsal

tunnel syndrome – diagnostic reliability of motor, mixed tunnel syndrome – diagnostic reliability of motor, mixed and sensory nerve conduction studies. Am J PM&R and sensory nerve conduction studies. Am J PM&R 1994.73:193.1994.73:193.

Gumasalum & Kalaycioglu: Bilateral accessory flexor Gumasalum & Kalaycioglu: Bilateral accessory flexor digitorum longus muscle in man.Annals of digitorum longus muscle in man.Annals of Annatomy.2000. 182:573.Annatomy.2000. 182:573.

References References Lee,C & Dellon,A: Diagnostic ability of Tinel sign in determining outcome Lee,C & Dellon,A: Diagnostic ability of Tinel sign in determining outcome

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Azsmann,O et al: Incidence of ulcer/amputation in the contralateral limb of Azsmann,O et al: Incidence of ulcer/amputation in the contralateral limb of patients with a unilateral nerve decompression procedure. Ann Plastic patients with a unilateral nerve decompression procedure. Ann Plastic Surg.2004. 53:517Surg.2004. 53:517

Kim,D et al: Surgical management and results of 135 tibial nerve lesions Kim,D et al: Surgical management and results of 135 tibial nerve lesions at the Louisiana State University Health Sciences Center. Neurosurgery. at the Louisiana State University Health Sciences Center. Neurosurgery. 2003. 53:lll42003. 53:lll4

Sammarco,G & Chang,L: Outcome of surgical treatment of tarsal tunnel Sammarco,G & Chang,L: Outcome of surgical treatment of tarsal tunnel syndrome. Foot & Ankle International.2003.24:125syndrome. Foot & Ankle International.2003.24:125

Labib,S et al: The combination of plantar fasciitis, posterior tibial tendon Labib,S et al: The combination of plantar fasciitis, posterior tibial tendon dysfunction and tarsal tunnel syndrome. Foot & Ankle Internation. dysfunction and tarsal tunnel syndrome. Foot & Ankle Internation. 2002.23:212.2002.23:212.

Watson, T et al: Distal tarsal tunnel release with 0artial plntar fasciotomy Watson, T et al: Distal tarsal tunnel release with 0artial plntar fasciotomy for chronic heel pain: an outcome analysis. Foot & Ankle International. for chronic heel pain: an outcome analysis. Foot & Ankle International. 2002. 23:5302002. 23:530

referencesreferences Watson, B et al: An unusual presentation Watson, B et al: An unusual presentation

of tarsal tunnel syndrome caused by an of tarsal tunnel syndrome caused by an inflatable ice hockey skate. Canadian J inflatable ice hockey skate. Canadian J Neurologic Sciences.2002.29:386Neurologic Sciences.2002.29:386

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neuroma of sural nerve. J Am Podiatric Med Assoc. 2001. 81:109neuroma of sural nerve. J Am Podiatric Med Assoc. 2001. 81:109 Kohno, M et al: Neurovascular decompression for idiopathic tarsal tunnel Kohno, M et al: Neurovascular decompression for idiopathic tarsal tunnel

syndrome: technical note. J Neurol Neurosurg Psychiatry. 2000.69:87syndrome: technical note. J Neurol Neurosurg Psychiatry. 2000.69:87 Bailie, D & Kelikian A: Tarsal tunnel syndrome: Diagnosis, surgical Bailie, D & Kelikian A: Tarsal tunnel syndrome: Diagnosis, surgical

technique and functional outcome.. Foot & Ankle International1998.19:65technique and functional outcome.. Foot & Ankle International1998.19:65 Herbsthofer, B et al: Tarsal tunnel syndrome: diagnostic and longgterm Herbsthofer, B et al: Tarsal tunnel syndrome: diagnostic and longgterm

follow-up after operative treatment.Zieitschrift fur Ortholpadie und Ihre follow-up after operative treatment.Zieitschrift fur Ortholpadie und Ihre Grenzgebiete. 1998. 136:77.Grenzgebiete. 1998. 136:77.

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Usefulness of EDX in DX Usefulness of EDX in DX of TTSof TTS

AANEM PRACTICE TOPICAANEM PRACTICE TOPIC Patel, A et al: Muscle & Nerve. 2005. 236Patel, A et al: Muscle & Nerve. 2005. 236 Recommendations:Recommendations:

Tibial motor CV with responses abd hall & abd Tibial motor CV with responses abd hall & abd dig min ped with prolonged latenciesdig min ped with prolonged latencies

Medial and Lateral Plantar prolonged latenciesMedial and Lateral Plantar prolonged latencies Medial and Lateral Plantar slowed CV across TT Medial and Lateral Plantar slowed CV across TT

or reduced or absent SNAPor reduced or absent SNAP Needle exam of foot intrinsic muscles – no data Needle exam of foot intrinsic muscles – no data