An anatomical approach to the tarsal tunnel syndrome: what can ankle's medial side anatomy reveal to us?

BACKGROUND: The heel is a complex anatomical region and is very often the source of pain complaints. The medial heel contains a number of structures, capable of compressing the main nerves of the region and knowing its anatomical topography is mandatory. The purpose of this work is to evaluate if tibial nerve (TN) and its main branches relate to the main anatomical landmarks of the ankle's medial side and if so, do they have a regular path after emerging from TN. METHODS: The distal part of the legs, ankles and feet of 12 Thiel embalmed cadavers were dissected. The pattern of the branches of the TN was registered and the measurements were performed according to the Dellon-McKinnon malleolar-calcaneal line (DML) and the Heimkes Triangle (HT). RESULTS: The TN divided proximal to DML in 87.5%, on top of the DML in 12,5% and distal in none of the feet. The Baxter's nerve (BN) originated proximally in 50%, on top of the DML in 12,5% and distally in 37.5% of the cases. There was a strong and significant correlation between the length of DML and the distance from the center of the medial malleolus (MM) to the lateral plantar nerve (LPN), medial plantar (MPN) nerve, BN and Medial Calcaneal Nerve (MCN) (ρ: 0.910, 0.866, 0.970 and 0.762 respectively, p <  0.001). CONCLUSIONS: In our sample the TN divides distal to DML in none of the cases. We also report a strong association between ankle size and the distribution of the MPN, LPN, BN and MCN. We hypothesize that location of these branches on the medial side of the ankle could be more predictable if we take into consideration the distance between the MM and the medial process of the calcaneal tuberosity.

Connection between medial dorsal cutaneous nerve and saphenous nerve: case report.

PURPOSE: There are no data on the connection of the saphenous nerve (SN), located on the medial side of the foot, with the terminal branches of the superficial fibular nerve. The aim of this study is to reveal the variation that surgeons should pay attention to for anesthesia applied in foot surgeries. METHODS: In this study, the left foot of a 70-year-old female cadaver fixed with formalin was dissected. The distance to the medial malleolus and the incision line was recorded using digital caliper to determine the reference points in the resulting variation. RESULTS: It was observed that a branch from the SN, which arose from the SN and proceeded anteriorly to the upper part of the medial malleolus and continued towards the dorsum of the foot, hooked with a branch from the medial dorsal cutaneous nerve (MDCN). The branches arising from this hook were distributed on the medial edge of the foot up to the proximal metatarsophalangeal joint I. The distance of this nerve connection to the medial malleolus is 91.14 mm, and the distance to the incision line is 15.76 mm. CONCLUSIONS: It is suggested that the case presented as an unusual SN variation, which may affect the success of local anesthesia in invasive procedures to the medial part of the foot and could be considered in the evaluation of sensory loss after anteromedial surgical approach to the ankle, should be included in the classification of the cutaneous innervation pattern of the foot.

Anatomical principles of ankle denervation - An update.

BACKGROUND: Denervation is a surgical option in ankle arthrosis when conservative therapy has failed. Sectioning all joint branches is essential for its success. The locations of the articular branches of the saphenous (Sa), tibial (Ti), sural (Su), superficial (Ps) and deep peroneal (Pp) nerves are specified. METHODS: In 16 cryopreserved specimens, the courses of the nerves were prepared. Their articular branches were identified, and their respective locations documented by using a new reference system. RESULTS: The articular branches to the ankle ranged from 5 to 30 cm measured from the foot sole. The Sa should be transected at 22.5 cm, the Su at 20 cm, and the Pp at 15 cm. The Ti should be skeletonized up to 25 cm. Epifascial dissection of the Ps is to be performed below 15 cm. CONCLUSION: The study specifies the joint branches of the ankle in an intraoperatively reproducible reference system and thus minimizes the required skin incisions.

Distal Tibial Mononeuropathy From Compression by the Posterior Tibial Artery: Clinical-Electrophysiological-Ultrasonographic Correlations.

SUMMARY: The tibial nerve is bound tightly to the posterior tibial artery in the tarsal tunnel where expansion capacity is limited. Therefore, the nerve may be vulnerable to, and damaged by chronic pulsatile trauma from an atypically positioned overriding artery, labeled "punched-nerve syndrome". In this article, we present a 49-year-old woman who presented with two months of severe burning pain in the left medial ankle and sole of the foot without antecedent trauma. Neurological examination identified dysesthetic sensation to light touch in the left medial sole of the foot, and both active and passive dorsiflexion worsened the painful paresthesia. Nerve conduction studies demonstrated a reduced left medial plantar mixed nerve action potential amplitude, 50% less than the right. High-resolution ultrasound (HRUS) showed an increased left tibial nerve cross-sectional area of 26 mm2 (normal <22.3 mm2) at the level of the ankle with side-to-side difference of 6 mm2 (normal <5.7 mm2). The distal tibial nerve and its medial plantar branch were atypically positioned immediately deep to the left posterior tibial artery and abnormally flattened with focal enlargement of the nerve on longitudinal view. Dynamic analysis demonstrated the nerve being compressed with each pulsation of the tibial artery immediately above. Active dorsiflexion of the ankle narrowed the space underneath the flexor retinaculum resulting in further compression of the nerve against the artery. In conclusion, HRUS as an adjunct to electrophysiological studies identified punched-nerve arterial compression as an etiology of tarsal tunnel syndrome.

Variations in the branching pattern of tibial nerve in foot: a review of literature and relevant clinical anatomy.

Considerable variations have been reported regarding the branching pattern of tibial nerve (TN) close to its termination in foot. In order to comprehend the clinical anatomy of heel pain awareness of all the possible variations in relation to terminal branching pattern of TN (close to the tarsal tunnel) is essential. The present study was conducted to undertake a comprehensive review of the variations in TN branches in foot with particular emphasis on the implications for sensory distribution of these branches. Articles were searched in major online indexed databases using relevant key words. The pattern of termination of TN was noted as either trifurcation or bifurcation. Bifurcation pattern was more commonly observed and is associated with the medial calcaneal nerve (MCN) either arising high or low relative to the tarsal tunnel. The most commonly noted type of bifurcation was proximal to malleolar-calcaneal axis but within the tarsal tunnel. Across all five types of bifurcation reported in literature, the termination points of TN ranged from 3 cm proximal to 3 cm distal to malleolar-calcaneal axis and, therefore, the area beyond this region can be considered as safe zone for performing invasive procedures. MCN showed considerable variations in its origin both in trifurcation and bifurcation pattern pertaining to number of branches (one/two/three) at the point of origin. The origin of inferior calcaneal nerve was observed to be relativelyless variable as it mostly arose as a branch of lateral plantar nerve and sometimes as a direct branch from TN before termination. The frequent variation of MCN in the tarsal tunnel should be kept in mind while undertaking decompression measures in medial ankle region.

Anatomy of the tibial nerve in relation to the tarsal tunnel: A cadaveric study.

BACKGROUND: Tarsal tunnel syndrome (TTS) is typically caused by an anatomical variant or mechanical compression of the tibial nerve (TN) with variable success after surgical treatment. METHOD: 40 lower-leg specimens were obtained. Dissections were appropriately conducted. Extremities were prepared under formaldehyde solution. The tibial nerve and branches were dissected for measurements and various characteristics. RESULTS: The flexor retinaculum had a denser consistency in 22.5% of the cases and the average length was 51.9 mm. The flexor retinaculum as an independent structure was absent and 77.2% of cases as an undistinguished extension of the crural fascia. The lateral plantar nerve (LPN) and abductor digiti minimi (ADM) nerve shared same origin in 80% of cases, 34.5% bifurcated proximal to the DM (Dellon-McKinnon malleolar-calcaneal line) line 31.2% distally and 34.3% at the same level. CONCLUSION: Understanding the tibial nerve anatomy will allow us to adapt our surgical technique to improve the treatment of this recurrent pathology.

A combined functional dorsal nerve model of the foot.

The nerves in the skin surface of the foot are comprised of unmyelinated smaller somatic nerves and larger myelinated sensory nerves. Current diagnostic methods are unable to evaluate combined nerve conduction velocity (NCV) from both unmyelinated smaller somatic nerve (USSN) and myelinated larger nerves (MLN) respectively. Computational models may provide an alternative tool to determine the NCV of the combined nerve. Therefore, a combined functional dorsal nerve model (CFDNM) of the various dorsal nerves along with its associated nerve ending of the human foot is proposed and constructed. The combined dorsal nerve model consists of synthetic USSN (SUSSN) and dorsal MLN of the foot. The unmyelinated as well as myelinated electrophysiological nerve models were used to simulate selected SUSSN and MLN of the foot by injecting an external stimulus at the most distal part of SUSSN of the foot through the use of bidomain model. Results from our work demonstrated that the action potential propagated from the most distal part to proximal part of distinct dorsal nerves of the foot, e.g., the simulated NCV of the combined intermediate dorsal cutaneous nerve (IDCN) of the foot was 28.4 m s-1. The CFDNM will provide a vital tool for diagnosis initially small fibre neuropathy (SFN) by computing NCV in the prospective studies.

[Clinical anatomical study on the treatment of tarsal tunnel syndrome with four-point vertical acupotomy].

OBJECTIVE: To explore safety and accuracy of four-point acupotomy for the treatment of tarsal tunnel syndrome regarding release of ankle tunnel flexor retinaculum to provide an anatomical basis of clinical treatment. METHODS: Twenty-nine adult specimens (15 males and 14 females) fixed with 10% formalin, aged from 47 to 98 years old with an average age of (81.10±11.14) years old, 29 on the right side and 29 on the left side, which were selected for the study from September 2020 to October 2020. Simulate the operation of loosening flexor retinaculumt with a needle knife on the human specimen, and place the specimen on the frog position of lower limbs with medial malleolus upward to determine the center of medial malleolus. Choose 4 different positions near the flexor retinaculum to insert the needle so that the needle body was perpendicular to skin and cutting edge direction was perpendicular to the running direction of the flexor retinaculum. The needle knife penetrates the skin and explores slowly. When the flexor retinaculum was reached, the needle tip may touch the tough tissue. At this time, the cutting is loosened for 4 times. After acupotomy release operation was completed, make a lateral incision on the skin surface along acupotomy direction, open the area of the exposed flexor retinaculum, dissecting layer by layer, observe and record the needle knife and its surrounding anatomical structure. The length of acupotomy cutting marks of flexor retinaculum was measured by electronic vernier caliper. The safety and accuracy of acupotomy loosening of ankle canal flexor retinaculum were evaluated by observing the number and degree of ankle canal contents such as tendons and nerves injured by needle knife. The safety is to count the number of cases of acupotomy injury to the contents of the ankle canal, and to calculate the injury rate, that is, the number of injury cases/total cases × 100%. The effective release was defined as the release length L ≥ W/2(W is the width of the flexor retinaculum, defined as 20 mm). RESULTS: For safety, there were no acupotomy injuries to nerves or blood vessels in 58 cases, 26 cases injuried to posterior tibial tendon which 17 of these tendon injury cases, the tendon was penetrated and severely injured, and flexor digitorum longus tendon was injured in 12 cases. Among these cases, tendon was penetrated and severely injured in 4 cases, and total injury rate was 32.14%. No nerve and vessel injury on c3 and c4 point. For accuracy, 58 specimens were successfully released. The length Lc of releasing trace for acupotomy was (10.40±1.36) cm, and length range 6.38 to 12.88 cm. Among all cases, the length of releasing trace was ≥10 mm in 37 cases. The overall success rate of release was 100.00%. Layered structure of ankle tube flexor retinaculumt:fiber diaphragm from flexor retinaculum divides contents of ankle tube into different chambers inward, and fiber diaphragm meets here to synthesize a complete flexor retinaculum at the midpoint of the line between the medial malleolus tip and calcaneal tubercle(above the neurovascular course). CONCLUSION: Four-point needle-knife method of releasing flexor retinaculum for the treatment of tarsal tunnel syndrome is performed at the attachment of the two ends of flexor retinaculum;the tendon, but not the nerves and blood vessels, is easily damaged. It is safe to insert needle on the side of calcaneus. The extent of release is relatively complete, but due to the "layered" structure of the flexor retinaculum, classic surgical technique could only release one layer of flexor retinaculum when a needle is inserted at the edge of the bone and cannot achieve complete release of the full thickness of the flexor. Therefore, it remains to be determined whether the desired effect can be achieved clinically.

Foot drop - an uncommon presentation of FOLFOX toxicity

A quimioterapia com FOLFOX (oxaliplatina, leucovorina e 5-fluorouracilo) é frequentemente utilizada em doentes com cancro colorretal. Os sais de platina são conhecidos por serem uma classe de quimioterápicos que comumente induzem neurotoxicidade periférica. Na toxicidade induzida pela oxaliplatina, os sintomas sensitivos são os mais frequentes. Neste artigo, apresentamos dois casos clínicos de pacientes com adenocarcinoma de cólon, ambos submetidos à quimioterapia com FOLFOX4, e que desenvolveram neurotoxicidade incomum, apresentando pé pendente após o terceiro ciclo de tratamento. Esta manifestação clínica pode ser explicada por dano axonal nos neurônios motores periféricos do nervo peroneal comum (fibular), que fornece inervação motora aos músculos do pé. A paralisia do nervo fibular causa fraqueza súbita nos músculos do pé, que parece ser temporária. Ambos os doentes recuperaram completamente do evento sem necessidade de ajustes no tratamento, nem introdução de medicamentos diferentes. A apresentação de pé pendente como toxicidade da quimioterapia ainda é pouco compreendida. Os casos relatados mostram o pé pendente como uma manifestação grave e incomum de neuropatia induzida por FOLFOX, que pode ser transitória, e não requer necessariamente intervenção específica.

Chemotherapy based on FOLFOX (oxaliplatin, leucovorin, and 5-fluorouracil) regimen is frequently used in colorectal cancer patients. Oxaliplatin and other platinum agents are known to be a class of chemotherapy drugs that commonly induce peripheral neurotoxicity. The most frequent oxaliplatin related neurotoxicity is sensitive symptoms. Here, we present two cases of patients with colon adenocarcinoma, both undergoing chemotherapy with FOLFOX4, who developed uncommon neurotoxicity, presenting with foot drop after the third treatment cycle. Foot drop may be explained by axonal damage of peripheral motor neurons of the common peroneal (fibular) nerve, which provides motor innervation to the foot muscles. Peroneal nerve palsy causes sudden weakness in the muscles of the foot that seems to be temporary. Both patients completely recovered from the event. There was no need for treatment adjustments, neither introduction of different drugs. Foot drop as chemotherapy toxicity is still poorly understood. The reported cases show foot drop as a severe and uncommon manifestation of FOLFOX-induced neuropathy, that might be transitory, and does not necessarily requires specific intervention.

Complications Associated with Peripheral Nerve Blocks.

Outpatient orthopedic surgery is gradually becoming the standard across the country, as it has been found to significantly lower costs without compromising patient care. Peripheral nerve blocks (PNBs) are largely what have made this transition possible by providing patients excellent pain control in the immediate postoperative period. However, with the increasing use of PNBs, it is important to recognize that they are not without complications. Although rare, these complications can cause patients a significant amount of morbidity. It is important for surgeons to know the risks of peripheral nerve blocks and to inform their patients.

Whole plantar nerve conduction study: A new tool for early diagnosis of peripheral diabetic neuropathy.

AIMS: Peripheral neuropathy (PN) affects two-thirds of type 2 diabetes patients (T2DM). According to diabetic PN length-dependent pattern, neurophysiological evaluation of foot-sole nerves might increase NCS diagnostic sensitivity, hence allowing early diagnosis of PN. Thus, we aim to assess the ability of whole plantar nerve (WPN) conduction in diabetic PN early diagnosis. METHODS: This is a single center prospective observational cohort study on 70 T2DM patients referred to Internal Medicine Unit of A.O.U. "Luigi Vanvitelli" between October 2019/October 2020. Primary endpoint was WPN efficacy assessment in PN early detection. As secondary, we evaluated (i) a potential cut-off of SNAPs amplitude by WPN and (ii) WPN diagnostic accuracy vs. gold-standard distal sural nerve conduction. RESULTS: ROC curve analysis allowed to establish two potential cut-offs for people aged ≤60 years (AUROC: 0.83, 95%CI: 0.69-0.96, p < 0.001) and ≤60 years (AUROC: 0.76, 95%CI: 0.59-0.93, p = 0.017). In depth, we fixed a cut-off of WPN-SNAP amplitude of 4.55 µV and 2.65 µV, respectively, with subsequent 48 patients classified as PN-T2DM. CONCLUSIONS: Our data support WPN conduction study reliability in characterizing the most distal sensory nerve fibers at lower limbs. Thus, WPN may represent an extremely useful diagnostic tool for diabetic PN early detection.

Identification of Optimal Foot Tactile Sensation Threshold for Detecting Fall Risk Among Community-Dwelling Older Adults.

OBJECTIVE: Foot tactile sensitivity loss, commonly assessed by monofilaments, is a fall risk factor among older adults. The broadly used threshold of the monofilament for fall risk assessment in older adults is 5.07. However, this threshold originates from assessing foot ulceration risk in people with peripheral neuropathy. The primary purpose of this study was to identify the optimal filament size and its cutoff number of sensitive sites that can be used to best identify a high risk of falls in terms of the foot tactile sensitivity for community-dwelling older adults. METHODS: In this cross-sectional study, the foot tactile sensitivity was assessed by a 6-piece Semmes-Weinstein monofilament kit at 9 sites per foot among 94 older adults, including 38 fallers and 56 nonfallers. The number of sensitive sites was determined for each monofilament size as the cutoff. Logistical regression analyses were used to determine the monofilament size and number of sensitive sites best able to differentiate fallers from nonfallers. RESULTS: Fallers showed overall worse foot tactile sensory measurements than nonfallers. Logistical regression analyses identified 4.31 as the best monofilament size and 7 as the number of sensitive sites to differentiate fallers from nonfallers with an accuracy of 71.3%. CONCLUSION: The 4.31 monofilament could be the best filament to detect the risk of falls among older adults in terms of tactile sensory loss. Inability to feel the pressure from the 4.31 filament at more than 7 sites could indicate a high risk of falls. IMPACT: These findings could help physical therapists and other rehabilitation professionals improve decision making in detecting older adults with a high risk of falls, thus facilitating the effort of fall prevention in older adults.

Long-Term Efficacy of T3 Versus T3+T4 Thoracoscopic Sympathectomy for Concurrent Palmar and Plantar Hyperhidrosis.

BACKGROUND: More than 50% of patients with palmar hyperhidrosis (PAH) also have plantar hyperhidrosis (PLH). We compared the long-term results of T3 sympathectomy with those of combined T3+T4 sympathectomy among patients with concurrent PAH and PLH. MATERIALS AND METHODS: We retrospectively analyzed the records of patients with concurrent PAH and PLH who underwent T3 alone or T3+T4 sympathectomy from January 1, 2012, to December 31, 2017. Preoperative and postoperative sweating (hyperhidrosis index) was evaluated through questionnaires, physical examination, and outpatient follow-up. The relief rates and hyperhidrosis index were used as outcome measures to compare the efficacy of the two approaches. Patients' satisfaction and side effects were also evaluated. RESULTS: Of the 220 eligible patients, 60 underwent T3 sympathectomy (T3 group), and 160 underwent T3+T4 sympathectomy (T3+T4 group). Compared with the T3 group, the T3+T4 group showed higher symptom relief rates both for PAH (98.75% versus 93.33%, P = 0.048) and PLH (65.63% versus 46.67%, P = 0.01), and a greater postoperative decrease in both hyperhidrosis indices. The rate of severe compensatory hyperhidrosis also increased (10% versus 5%, P = 0.197), although the rates of overall satisfaction were comparable between the groups. The incidence of postoperative pneumothorax requiring chest tube placement and postoperative neuralgia was also similar. There were no cases of perioperative death, secondary operation, wound infection, or Horner syndrome in either group. CONCLUSIONS: Compared with T3 alone, T3+T4 sympathectomy achieved a higher symptom relief rate and a lower hyperhidrosis index. T3+T4 sympathectomy may be a choice for the treatment of concurrent PAH and PLH; however, patients need to be informed that this kind of surgery may increase the risk of compensatory sweating.

Novel, user-friendly landmarks for localizing Baxter's nerve: A cadaveric study.

INTRODUCTION: Identification of Baxter's nerve (BN) has proven challenging for less experienced practitioners using ultrasonography due to a lack of adequate landmarks. This study aimed to establish novel, user-friendly anatomical landmarks and to describe useful structures to localize BN. MATERIALS AND METHODS: We examined 10 fresh cadaveric feet and identified the interobserver agreement of measuring three surface landmarks: the most medially protruded point on the medial malleolus (P), the navicular tuberosity (Q), and the center of the calcaneus (B). Next, 24 fresh cadaveric feet were used to identify the point of BN entry into the quadratus plantae (QP) muscle, which corresponds to the proximal BN impingement site. The rectangular coordinate system consisted of the origin (point P), X-axis, extension line P-Q, and Y-axis (the perpendicular line to the X-axis). To consider various foot sizes, the X and Y values were divided by the P-Q length and were designated as the ratios X and Y. RESULTS: Points P and Q showed smaller interobserver differences than that of point B. Ratios X and Y were 61.25 and 99.80%, respectively, for the QP. BN arose from the lateral plantar nerve in 20 of 24 specimens. The adjacent vessel was <3 mm from the entrapment site of BN in 20 of 24 specimens. CONCLUSION: New landmarks will improve the precision of localizing the entrapment site of BN and will provide advanced guidelines for podiatric patients.

Microcirculatory changes in venous leg ulcers using intermittent electrostimulation of common peroneal nerve.

OBJECTIVE: Activation of the venous muscle pumps of the leg by intermittent transdermal neuromuscular stimulation of the common peroneal nerve has been previously shown to augment venous and arterial flow in patients with leg ulcers. This study aims to establish if microcirculation in the wound bed and periwound area are augmented by the activation of a neuromuscular electrostimulation device (NMES) (Geko, Firstkind Ltd., UK). METHOD: In this self-controlled, observational study, laser speckle contrast imaging was used to map and quantify microcirculatory flow in the wound bed and periwound area of patients with venous leg ulcers (VLU). Values of flow and pulsatility in these locations were compared with the NMES device, both active and inactive. RESULTS: A total of 16 patients took part in the study. Microvascular flux increased by 27% (p=0.014) in the wound bed, and by 34% (p=0.004) in the periwound area, when the NMES device was activated. Pulsatility increased by 170% (p<0.001) in the wound bed and 173% (p<0.001) in the periwound area when the device was activated. CONCLUSION: Intermittent electrostimulation of the common peroneal nerve substantially increased both microcirculatory flux and pulsatility in the wound bed and in the periwound area of the VLUs of patients in this study. This provides a plausible mechanistic explanation for its reported efficacy in healing VLUs.

Clinical characteristics of 93 cases of isolated macrodactyly of the foot in children.

BACKGROUND: The purpose of this study was to describe the clinical characteristics of macrodactyly of the foot through a large cohort of cases to further understand this rare entity. METHODS: Medical records, clinical photographs, plain radiographs, pathological findings, and intraoperative photographs of 95 feet of 93 patients were reviewed. Data including age; sex; laterality; ethnicity; birthplace; family history; and history of gestation, environment, whether smoking, or drinking during pregnancy were collected and analyzed. RESULTS: Female patients (60%), left foot (56%), and static overgrowth (63%) were more prominent in the study cohort. Southern provinces (74%) and Han Chinese ethnicity (95%) predominated in terms of geographical region and demographic distribution, respectively. Multiple-toe involvement was 2.01-times more frequent than single-toe involvement. All five toes were involved with midline toes being most frequently affected overall and a medial distribution being more common than a lateral one. The forefoot was affected in 90 feet. The affected areas (toes and forefeet) were mostly located in the innervation of the affected medial plantar nerve (91%). The nerves showed enlargement in 49 feet, fatty infiltration in 25, a tortuous course in one, and were normal in 10 feet. Only six feet involved the musculature. Enlargement of phalanges and metatarsals were observed in 92 and 57 feet, respectively, and advanced bone maturation was seen in 63 feet. Twenty-two cases had syndactyly. CONCLUSIONS: Macrodactyly of the foot is a rare congenital malformation with diverse clinical manifestations and multiple elements' involvement. It also presents the characteristics of nerve-mediated overgrowth and "nerve territory-oriented" deformity similar to that of macrodactyly of the hand.