Tarsal Tunnel Syndrome Associated with an Accessory Muscle

Abstract

Between 1986 and 1999, we surgically treated 41 patients (49 feet) with Tarsal Tunnel Syndrome (TTS) in whom seven (eight feet) were associated with an accessory muscle. An accessory flexor digitorum longus muscle was present in six patients, and an accessory soleus muscle was in one patient (both feet). Three of them were males and four females, with the mean age of 33.1 years (12 to 59 years). The mean interval from the onset of symptoms to operation was 7.5 months (range, six to nine months). All patients with an accessory muscle had a history of trauma or strenuous sporting activity. The diagnosis of TTS was made based on physical findings in all the patients (eight feet) and confirmed in five patients (six feet) by electrophysiological examination. Imaging examinations (radiography, ultrasonography, MRI) revealed abnormal bone and soft tissue lesions in and around the tarsal tunnel. Preoperative signs and symptoms disappeared average 4.1 months after decompression of the tibial nerve in addition to excision of the muscle. No functional deficit was observed at final follow-up (24 to 88 months).

An unusual variation of the flexor digitorum accessorius longus muscle—its anatomy and clinical significance

“…Most recent studies of the FDAL (Peterson et al 1995;VanCourt and Siesel 1996;Deroy et al 2002;Eberle et al 2002;Kinoshita et al 2003;Jaijesh et al 2006;Wittmayer and Freed 2007) report an incidence of 5-13% in the population and 2-8% in all lower extremities. Many authors assume the higher percentage to be accurate, and note that such a relatively common anomaly continues to be unduly ignored in textbooks and poorly characterized.…”

“…The two-headed FDAL muscles previously described are more L-shaped than V-shaped because of the size disparity of the short and long heads. Both singleheaded and double-headed FDAL muscles usually have fleshy muscle fibers entering the tarsal tunnel, a primary reason they can cause tarsal tunnel syndrome (Nathan et al 1975;Lau and Daniels 1999;Kinoshita et al 2003). Nathan et al (1975, p. 160) emphasized that ''None of the other muscles [running through the tarsal tunnel] ever preserve fleshy fibers in the tunnel,'' and said that the FDAL ''… very frequently preserved its fleshy fibers, and could easily be identified by this characteristic.''…”

“…It was originally considered an example of entrapment neuropathy (similar to carpal tunnel syndrome), but it can be caused by trauma, space-occupying lesions, or skeletal deformities of the foot (Lau and Daniels 1999). The presence of an accessory muscle (the FDAL) in the vicinity of the tarsal tunnel has recently been recognized as a class of space-occupying lesion that may contribute to tarsal tunnel syndrome (Sammarco and Stephens 1990;Sammarco and Conti 1994;Kinoshita et al 2003).…”

“…The presence of accessory long digital flexor muscles in the leg was recorded almost 150 years ago (Wood 1864), but in the past two decades these structures have attracted renewed interest because of their implication in tarsal tunnel and flexor hallucis syndromes (Sammarco and Stephens 1990;Sammarco and Conti 1994;Canter and Siesel 1997;Lau and Daniels 1999;Burks and DeHeer 2001;Kinoshita et al 2003;Wittmayer and Freed 2007). Both of these syndromes manifest with pain in the foot and ankle, and can be caused by several different phenomena, rendering diagnosis and management problematic.…”

Presença do tendão flexor acessório longo dos dedos no tratamento cirúrgico da tendinopatia insercional do tendão calcâneo: relato de caso

“…3 Músculos anômalos no pé e no tornozelo habitualmente não causam sintomatologia, porém na sobrecarga excessiva, como em atletas, podem ocasionar dor, instabilidade e bloqueio articular. 4,5 Afecç ões no tornozelo podem ocorrer, nas quais os tendões acessórios (efeito de massa) podem provocar compressão e ocasionar impacto posterior no tornozelo, sín-drome do túnel do tarso, síndrome do flexor do hálux e dor crônica após entorses. [3][4][5][6] O exame de RNM é fundamental para elucidação de afecç ões posteriores do tornozelo, seja na identificação e no diagnóstico diferencial, com tumores e auxílio na escolha da via cirúrgica.…”