Tarsal Tunnel Release Research Articles

Ultrasound-guided decompression surgery of the distal tarsal tunnel: a novel technique for the distal tarsal tunnel syndrome\u2014part\xa0III

BackgroundThe aim of this study was to provide a safe ultrasound-guided minimally invasive surgical approach for a distal tarsal tunnel release concerning nerve entrapments.Methods and resultsThe study was carried out on ten fresh-frozen feet. All of them have been examined by high-resolution ultrasound at the distal tarsal tunnel. The surgical approach has been marked throughout the course of the medial intermuscular septum (MIS, the lateral fascia of the abductor hallucis muscle). After the previous steps, nerve decompression was carried out through a MIS release through a 2.5 mm (± 0.5 mm) surgical portal. As a result, an effective release of the MIS has been obtained in all fresh-frozen feet.ConclusionThe results of our anatomic study indicate that this novel ultrasound-guided minimally invasive surgical approach for the release of the MIS might be an effective, safe and quick decompression technique treating selected patients with a distal tarsal tunnel syndrome.

Ultrasound-Guided Release of the Tibial Nerve and Its Distal Branches: A Cadaveric Study.

The purpose of the study was to determine whether ultrasound (US)-guided surgery is a viable type of surgery for performing an effective release/decompression of the constricting structures that are responsible for focal nerve compression in tarsal tunnel syndrome. Ultrasound guidance was used on cadaveric specimens to delineate the anatomic course of the nerves and vessels in the medial ankle that comprise the structures involved in tarsal tunnel syndrome. Ultrasound guidance was used on cadaveric specimens and assisted in delineating a safe surgical zone to adequately and effectively release these constrictive structures of the proximal and distal tarsal tunnels. The US-guided tarsal tunnel release/decompression was performed through 2 small 1- to 2-mm portals. After US-guided release, anatomic dissection was used to check the efficacy (release of the flexor retinaculum and deep abductor hallucis muscle) and safety (absence of neurovascular or tendon injury) of the procedure. In 12 fresh cadaveric specimens, US-guided release of the tibial nerve (proximal tarsal tunnel) and its branches (distal tarsal tunnel) at the medial ankle was effective in all 12 specimens (100% release rate), without any signs of compromise or injury into the neurovascular structures. Ultrasound-guided tarsal tunnel release is a feasible surgical procedure that can be safe and effective with the proper training, although further investigation is warranted. This type of surgery may promote faster recovery with less postoperative morbidity, including pain, but this will be the subject of a further investigation.

Ultrasound-guided decompression surgery of the tarsal tunnel: a novel technique for the proximal tarsal tunnel syndrome\u2014Part II

BackgroundThe aim of this study is to provide a safe ultrasound-guided minimally invasive surgical approach for a proximal tarsal tunnel release concerning nerve entrapments.Methods and resultsThe study was carried out on ten fresh-frozen feet. All of them were examined by high resolution ultrasound at the medial ankle region. The surgical approach was marked throughout the course of the flexor retinaculum (laciniate ligament). Once the previous steps were done, the flexor retinaculum release technique was carried out with a 2-mm entry only. As a result, an effective and safe release of the flexor retinaculum was obtained in all fresh-frozen feet.ConclusionThe results of our anatomic study indicate that our novel ultrasound-guided minimally invasive surgical approach for the release of the flexor retinaculum might be an effective, safe and quick decompression technique treating selected patients with a proximal tarsal tunnel syndrome.

A study of effect of tarsal tunnel decompression on sensory improvement in diabetic foot: a prospective randomized control trial

Background: In India approximately, 45000 legs are amputated every year and almost 75% of these amputations are carried out in neuropathic feet which are potentially preventable. Diabetic peripheral nerves are at risk of entrapment neuropathies focally, where these nerves are contained in a closed space. The aim of the study was to find out the effect of decompression of compressed posterior tibial nerve and its branches at tarsal tunnel in restoration of sensation in diabetic foot.Methods: A total of 70 diabetic patients with ulcer foot in one limb (test limb) and with no ulcer on the other limb (control limb) were selected for study. The test limb was subjected to tarsal tunnel release. Sensory recovery was evaluated in the ulcer limb and compared with normal limb in same patient and results were evaluated statistically for significance.Results: Present study shows that following tarsal tunnel decompression surgery on test limb, 65 patients (93%) had sensory gain and 5 patients (7%) had documented no sensory gain on test limb, with statistical significance. After de-compressive surgery on the test limb, 69 patients (98.6%) were documented to have resolving of Tinel sign in the test limb with sensory improvement, suggesting adequate decompression and 1 patient (1.4%) was documented to have persistent Tinel sign suggesting possibility of inadequate decompression with no recovery of sensation, with statistical significance.Conclusions: Present study reveals that decompression of tarsal tunnel in diabetic ulcer foot patients leads to definite improvement in sensation of foot which will prevent further ulcer formation and resultant complications ending in amputations.

Posterior ankle arthroscopy: current state of the art

The most common hindfoot pathologies seen in clinical practice and sports medicine are posterior ankle impingement and osteoarthrosis (OA). Both these—and other pathologies such as insertional tendinitis and Haglund’s disease—may cause significant disability, in both everyday life and during sporting activities. Post-traumatic OA alone causes a healthcare burden of over 3 billion US dollars per year. An adequate approach of these pathologies is required to minimise this healthcare burden and additionally to maintain patients’ economic productiveness. The aim of this article is to outline the most important evidence-based indications concerning posterior ankle arthroscopy focusing on diagnostics, surgical techniques, complications, geographical differences and future developments in the field of hindfoot arthroscopy. Initially, the treatment of hindfoot pathology is conservative. If adequate conservative treatment does not result in a good response, surgery may be indicated. Over the last three decades, arthroscopy of the ankle joint has become a standardised and important procedure, with numerous indications for both anterior and posterior pathology. Since 2000, a two-portal hindfoot arthroscopic approach has been described and used globally in clinical practice. Some of the indications that may be addressed using this approach are the treatment of posteriorly located osteochondral defects, posterior ankle impingement, pathology of the deep portion of the deltoid ligament, Cedell fracture, tarsal tunnel release, loose bodies and tibiotalar or subtalar arthrodesis. Tendon pathology can also be treated using posterior portals; however, this is beyond the scope of this review.

Tarsal tunnel release: Medium-term outcomes and complications

To retrospectively compare the initial response, local recurrence, and complication rates of radiofrequency ablation (RFA) vs microwave ablation (MWA) when combined with neoadjuvant bland transarterial embolization (TAE) or drug-eluting microsphere chemoembolization (TACE) for the treatment of hepatocellular carcinoma (HCC).A total of 35 subjects with Barcelona Clinic Liver Cancer (BCLC) very early and early-stage HCC (range: 1.2-4.1 cm) underwent TAE (23) or TACE (12) with RFA (15) or microwave ablation (MWA) (20) from January 2009 to June 2015 as either definitive therapy or a bridge to transplant. TAE and TACE were performed with 40-400 μm particles and 30-100 μm plus either doxorubicin- or epirubicin-eluting microspheres, respectively. Initial response and local progression were evaluated using modified response evaluation criteria in solid tumors. Complications were graded using common terminology criteria for adverse events version 5.0.Complete response rates were 80% (12/15) for RFA + TAE/TACE and 95% (19/20) for MWA + TAE/TACE (P = 0.29). Local recurrence rate was 30% (4/12) for RFA + TAE/TACE and 0% (0/19) for MWA + TAE/TACE. Durability of response, defined as local disease control for duration of the study, demonstrated a significant difference in favor of MWA (P = 0.0091). There was no statistical difference in complication rates (3 vs 2).MWA and RFA when combined with neoadjuvant TAE or TACE have similar safety and efficacy in the treatment of early-stage HCC. MWA provided more durable disease control in this study; however, prospective data remain necessary to evaluate superiority of either modality.

Tarsal Tunnel Release

Category: Ankle Introduction/Purpose: Tarsal tunnel release is a standard surgical treatment for patients who have tarsal tunnel syndrome and failure of conservative treatment. However, there remains little evidence demonstrating the medium-term of functional outcomes and complications of tarsal tunnel release. The purpose of this study was to report functional outcomes and complications of tarsal tunnel release. Methods: Retrospective chart review with prospectively collected data of 79 consecutive patients with 87 feet (primary surgery = 74/80 and revision surgery = 5/5) who were diagnosed with tarsal tunnel syndrome and underwent tarsal tunnel release between 2008 and 2014. Diagnosis bases on history and physical examination. All patients were failure of conservative treatment at least 6 weeks and the minimum follow up to be included in the study was 12 months (mean, 32.2 months; range, 12 to 80 months). The primary outcome was visual analogue scale (VAS), Short Form-36 (SF-36); physical and mental component scores, and Foot Function Index (FFI); pain, disability, activity limitation, and total score. Pre- and post-operative SF-36, and Foot Functional Index (FFI), pain (Visual Analog Scale) were obtained and compared using pair t-test. The secondary outcomes were operative time, time to return to activity of daily living and work, and complications. Mann-Whitney U-test was used to compare non-parametric data and Wilcoxon signed ranks test was used to compare parametric data. Results: The VAS was significantly decrease from 7.6 to 2.0(p = 0.001) and SF-36 was significantly improved from 33.2 to 40.2, for PCS (p= 0.001) and 47.7 to 49.7 for MCS (p = 0.005). The FFI was significantly decreased from 63.0 to 36.0, 61.9 to 35, 72.5 to 34.9, and 65.8 to 35.3 for pain, disability, activity limitations, and total scores(p=0.001, all). Mean operative time was 36.1 minutes for primary surgery and 54.8 minutes for the revision surgery. There 45 of 87 feet (51.7%) had positive Tinel test pre-operatively and 9 of 87 feet (10.3%) post-operatively. Revision surgery demonstrated significantly worse outcomes (VAS,SF-36,and FFI) compared to primary surgery(p < 0.05) but duration >12 months and Tinel sign did not affect the outcomes compared to duration >12 months and Tinel sign negative (p>0.05 all). An average time to return to activity of daily living and work was 8.1 and 9.5 weeks. Complications were painful scar(14.9%), wound infection(6.9%), CRPS(2.3%), and paresthesia on the foot(20.7%). Conclusion: Tarsal tunnel release demonstrated significant improvement of functional outcomes and pain relief in medium-term follow-up as measured with SF-36, FFI, and VAS. Revision surgery demonstrated less favorable outcomes while pre-operative Tinel test and duration of symptom more than 12 months did not affect the outcome. This procedure was effective and feasible for tarsal tunnel syndrome with minor complications.

Neurologic Deficit Associated With Lateralizing Calcaneal Osteotomy for Cavovarus Foot Correction.

Lateralizing calcaneal osteotomy (LCO) is a frequently used technique to correct hindfoot varus deformity. Tibial nerve palsy following this osteotomy has been described in case reports but the incidence has not been quantified. Eighty feet in 72 patients with cavovarus foot deformity were treated over a 6-year span by 2 surgeons at their respective institutions. Variations of the LCO were employed for correction per surgeon choice. A retrospective chart review analyzed osteotomy type, osteotomy location, amount of translation, and addition of a tarsal tunnel release in relation to the presence of any postoperative tibial nerve palsy. Tibial nerve branches affected and the time to resolution of any deficits was also noted. The incidence of neurologic deficit following LCO was 34%. With an average follow-up of 19 months, a majority (59%) resolved fully at an average of 3 months. There was a correlation between the development of neurologic deficit and the location of the osteotomy in the middle third as compared to the posterior third of the calcaneal tuber. We found no relationship between the osteotomy type, amount of correction, or addition of a tarsal tunnel release and the incidence of neurologic injury. Tibial nerve palsy was not uncommon following LCO. Despite the fact that deficits were found to be transient, physicians should be more aware of this potential problem and counsel patients accordingly. To decrease the risk of this complication, we advocate extra caution when performing the osteotomy in the middle one-third of the calcaneal tuberosity. Although intuitively the addition of a tarsal tunnel release may protect against injury, no protective effect was demonstrated in this retrospective study. Level III, retrospective cohort study.

Failed Agility LP Total Ankle Replacement with Severe >40 Varus Deformity Revision with Prosthesis Conversion and Soft-Tissue Procedures Alone

Achieving frontal plane alignment of the ankle joint during primary and revision total ankle replacement is essential for long-term success. This manuscript presents the revision of a failed Agility™ LP total ankle replacement system with severe > 40° varus ankle deformity that was corrected with explanation and conversion to an INBONE™ II total ankle system coupled with soft-tissue release/reconstruction employing percutaneous Achilles tendon lengthening, posterior tibial tendon intramuscular recession lengthening and modified Evans peroneus longus lateral ankle stabilization. Additionally, prophylactic tarsal tunnel release was performed to reduce potential for postoperative nerve compression. At short-term 2.5-years follow-up the patient had a well-balanced and painless foot/ ankle and return of a functional lower limb.

Acute tarsal tunnel syndrome in a pregnant woman following surgical repair of bimalleolar fracture: A case report and review of the literature

Tarsal tunnel syndrome is generally a subacute condition that gradually develops and worsens with time. Urgent tarsal tunnel release to treat an acute onset of symptomatic neurocompression within the tarsal tunnel following a fracture repair has not been previously reported. We present a case of a pregnant woman who developed an acute tarsal tunnel syndrome following an open reduction internal fixation of an ankle fracture. The urgent release of the tarsal tunnel resulted in resolution of her symptoms.

Endoscopic tarsal tunnel syndrome surgery using the Universal Subcutaneous Endoscope system

Background/objectiveTarsal tunnel syndrome is a relatively rare entrapment neuropathy with the lateral and medial plantar nerves entrapped inside of the tarsal tunnel. When conservative treatment fails, standard open decompression of the nerve can be achieved by releasing the flexor retinaculum of the foot through a several-centimetre-long skin incision made along the tarsal tunnel. By contrast, we made a 1-cm portal incision at the proximal part of the medial ankle, and endoscopic tarsal tunnel release of the flexor retinaculum of the foot and part of the abductor hallucis muscle was achieved using the Universal Subcutaneous Endoscope (USE) system. MethodsOur procedure was performed under local anaesthesia without a pneumatic tourniquet on an outpatient basis. The USE system was inserted into the tarsal tunnel at the proximal part of the medial ankle; the nerves, vessels, flexor retinaculum, tendons of the foot, and the abductor hallucis muscle were then endoscopically identified. Decompression of the lateral and medial plantar nerves entrapped inside of the tarsal tunnel was then achieved by releasing the flexor retinaculum of the foot and part of the abductor hallucis muscle with a push knife under complete endoscopic observation. ResultsResults from eight feet of five patients were compiled and analyzed. All showed improved clinical signs compared with their preoperative condition. ConclusionOur less invasive endoscopic management for tarsal tunnel syndrome using the USE system produces sufficient results.

Results and complications of operative and non-operative navicular fracture treatment

BackgroundNavicular fractures (NF) are uncommon. The purpose of this study was to compare results of operative (ORIF) and non-operative (NOT) treatment in NF. MethodsA retrospective analysis was undertaken on patients diagnosed with NF between March 2002 and June 2007 at a Level I teaching trauma centre. Clinical outcome consisted of functional ability and complications. ResultsEighty-eight patients with 90 fractures were identified including 56 males and 32 females with a mean age of 38 (range 17–72) and body mass index of 28.2 (range 18.7–48.9). Twenty-one of 90 (23.3%) injuries were isolated. Ten of 90 (11.1%) injuries were open. Treatment was 49/90 (55%) NOT and 41/90 (45.6%) ORIF. 11/41 (30%) ORIF required bone grafting. Complications included one ipsilateral deep vein thrombosis, one avascular necrosis, one nonunion, seven infections (two deep and five superficial), and 56 cases of secondary osteoarthrosis (SOA). ORIF had significantly more SOA (χ2=0.000). Secondary surgery was 25 hardware removals (16 for irritation, five for prominent or broken plates), nine arthrodeses/-plasties, two debridements for infection, and one tarsal tunnel release. Pain was present at final follow up in 39/90 (43.3%) feet. Work status was 64 without restrictions, 17 with restrictions, and 5 did not return to work. Sixty-two of 88 (69%) patients were able to wear normal shoes, which were related to return to work without restrictions (ρ=−0.508, p=0.000). Inability to return to previous work was related to pain (ρ=−0.394), SOA (ρ=−0.280), and poor reduction quality (ρ=−0.384) with significance at p<0.01. Increased BMI (>35) related to pain (ρ=0.250) and poor reduction quality (ρ=0.326) at a σ<0.05. ConclusionsDespite modern surgical techniques, operative treatment of displaced fractures is at high risk for complications. Obesity, pain, and secondary osteoarthrosis determine shoe wear, return to function, and employment status. Level of EvidenceLevel III.

Evaluation of peripheral microcirculation improvement of foot after tarsal tunnel release in diabetic patients by transcutaneous oximetry.

According to recent studies, peripheral nerve decompression in diabetic patients seems to not only improve nerve function, but also to increase microcirculation; thus decreasing the incidence of diabetic foot wounds and amputations. However, while the postoperative improvement of nerve function is demonstrated, the changes in peripheral microcirculation have not been demonstrated yet. The aim of this study is to assess the degree of microcirculation improvement of foot after the tarsal tunnel release in the diabetic patients by using transcutaneous oximetry. Twenty diabetic male patients aged between 43 and 72 years old (mean age 61.2 years old) suffering from diabetic peripheral neuropathy with superimposed nerve compression underwent transcutaneous oximetry (PtcO2) before and after tarsal tunnel release by placing an electrode on the skin at the level of the dorsum of the foot. Eight lower extremities presented diabetic foot wound preoperatively. Thirty-six lower extremities underwent surgical release of the tibialis posterior nerve only, whereas four lower extremities underwent the combined release of common peroneal nerve, anterior tibialis nerve, and posterior tibialis nerve. Preoperative values of transcutaneous oximetry were below the critical threshold, that is, lower than 40 mmHg (29.1 ± 5.4 mmHg). PtcO2 values at one month after surgery (45.8 ± 6.4 mmHg) were significantly higher than the preoperative ones (P = 0.01). The results of postoperative increase in PtcO2 values demonstrate that the release of the tarsal tunnel determines a relevant increase in microcirculation in the feet of diabetic patients.

The Effect of Medial and Lateral Calcaneal Osteotomies on the Tarsal Tunnel

As an entrapment phenomenon, tarsal tunnel syndrome has been described after calcaneal osteotomy, and since the tibial nerve has also been shown to be very sensitive to ankle position, position of the calcaneus after osteotomy and displacement was thought to likely influence the environment of the tibial nerve within the tarsal canal. The respective volume of the tarsal canal was therefore hypothesized to decrease with medial or lateral displacement osteotomies of the calcaneus. Anterior and posterior calcaneal osteotomies were made in cadaveric matched pairs and brought through sequential medial and lateral displacements. Magnetic resonance imaging was used to estimate the comparative resultant volume of the tarsal canal after each of these new positions were assumed, as compared with baseline. The proximity of the osteotomy cut to the nerve's location was also measured. The tarsal tunnel volume was calculated for all 5 displacement states and were as follows: far-lateral (9506 mm(3)), near-lateral (10 073 mm(3)), normal (11 839 mm(3)), near-medial (11 489 mm(3)), and far-medial (11 760 mm(3)). No significant difference in tarsal tunnel volume was identified between the normal, nondisplaced specimens in the anterior or posterior groups (11 954 mm(3) vs 11 809 mm(3)). No difference in tarsal tunnel volume was identified between the anterior and posterior osteotomies at any of the 4 displacements. The distance from tibial nerve to the medial exit site of the osteotomy was found to be significantly less in the anterior group compared to the posterior group (4 mm vs 14.2 mm, P < .0001). Lateral, but not medial, osteotomy fragment displacement results in significant reduction of tarsal tunnel volume. The location of the cut does not seem to affect any substantive change in volume. Anteriorly placed osteotomies appear to jeopardize the neurovascular structures more than posteriorly placed osteotomies. These findings provide surgeons with clinical evidence in support of performing a prophylactic tarsal tunnel release for patients undergoing lateralizing calcaneal osteotomies.

Extensile Decompression of the Proximal and Distal Tarsal Tunnel Combined With Partial Plantar Fascia Release in the Treatment of Chronic Plantar Heel Pain

Chronic heel pain that is recalcitrant to nonoperative measures is a rare but disabling condition. There are no reports in the literature of extensile proximal and distal tarsal tunnel release combined with partial plantar fasciotomy in the treatment of chronic heel pain. We present our results. A retrospective chart review was conducted, and charts were assessed for details of their presenting complaints, physical exam, diagnostic studies, medical history, Visual Analog Scale (VAS) scores for pain, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores, and complications. The mean AOFAS ankle-hindfoot score was 86 ± 12.9 (range = 69-100). Of 15 heels, 10 (67%) had an excellent or good rating at the time of the last follow-up visit. One of 15 (7%) reported a poor outcome. The mean VAS pain score changed from 6.3 ± 3.1 to 1.4 ± 1.8 (P = .001). There were no wound complications or infections. This technique offers another operative option for chronic heel pain that is associated with satisfactory outcomes and rest pain relief. Despite reducing pain at rest in all patients, the majority of patients may be left with mild to moderate residual symptoms with activity that is similar to the outcomes of previously reported procedures.

Entrapment of the Lateral Plantar Nerve Distal to the Tarsal Tunnel: A Case Report

Tibial nerve entrapment is a common cause of foot pain. Identifying the location of the entrapment may be difficult. This case report describes the electrodiagnosis of the lateral plantar nerve branch of the tibial nerve in a 50 year-old woman who failed to respond to the local steroid injection for plantar fasciitis and subsequently a tarsal tunnel release. The etiology of the nerve entrapment is discussed as well as the role of electrodiagnostic studies to locate the nerve entrapment. This case highlights the role of meticulous clinical evaluation and electrodiagnosis for the diagnosis of this challenging condition and a simple in-office treatment to reduce patient’s symptoms.

Touch pressure and sensory density after tarsal tunnel release in diabetic neuropathy

Limited quantitative information is available about the improvement of protective sensation after tarsal tunnel release in patients with diabetic peripheral neuropathy. Prospective, non-blinded, non-randomized case series of 10 feet in 8 diabetic patients and 24 feet in 22 non-diabetic patients who had tarsal tunnel release. Preoperative and postoperative (average, 8-9 months) anatomic, quantitative sensory testing was done with touch pressure 1-point threshold (Semmes-Weinstein monofilaments) and 2-point discrimination. There was marked, significant postoperative improvement of mean touch pressure 1-point threshold, compared with preoperative values, for medial calcaneal, medial plantar, and lateral plantar nerves in both non-diabetic and diabetic patients. There was minimal improvement in 2-point discrimination only for the medial calcaneal nerve in non-diabetic, but not in diabetic, patients. Nerve entrapment at the tarsal tunnel is an important component of diabetic peripheral neuropathy. Tarsal tunnel decompression may improve sensory impairment and restore protective sensation.

Anatomical bases of endoscopic tarsal tunnel release: anatomical and ultra-sonographic study with a preliminary clinical report

The purpose of our study is to present the anatomical bases of a new technique for endoscopic tarsal release and to report the preliminary clinical outcome for this technique. Anatomical study The technique was performed on 12 intact adult lower limb specimens. The location of portals was evaluated as well as the integrity of the neurovascular bundle. Ultra-sonographic study A prospective case control study was done on 10 patients (11 feet) and 14 normal volunteers (28 feet). Three parameters were measured; the thickness of flexor retinaculum, the nerve cross-section area and the depth of tarsal tunnel. Clinical study Seven patients with idiopathic proximal Tarsal Tunnel Syndrome (TTS) were treated by endoscopic TTR using a modified trocar cannula and dilator system. Preoperative and postoperative evaluation was done by electrophysiological studies and ultra-sonography. Evaluation was done using Takakura's rating scale. Anatomical study The proximal and distal portals were located at 13 mm (±1.59 STD) and 17.91 mm (±1.44 STD) from the proximal and distal borders of FR, respectively. There was intact neurovascular bundle in all specimens. Ultra-sonographic study There was statistically significant difference in the mean nerve cross-sectional area and the thickness of the FR between the control group and the patients group (P < 0.05). Clinical study The mean TRS improved from 2.28 ± 1.11 STD preoperatively to 8.43 ± 0.97 at 2 years follow-up. The overall good to excellent results was 85.7%. Based on this preliminary clinical study, endoscopic tarsal tunnel release by the technique described could obtain excellent to good results in 85.7% of patients with idiopathic proximal tarsal tunnel. The anatomical study proved the safety of the technique on the neurovascular structures. Ultra-sonography was an effective tool for preoperative diagnosis and postoperative follow-up. Case series study, Level IV.

A novel MPZ mutation in Charcot–Marie–Tooth disease type 1B with focally folded myelin and multiple entrapment neuropathies

Charcot–Marie–Tooth type 1B (CMT1B) is a demyelinating neuropathy caused by mutations in the myelin protein zero (MPZ) gene. Here, we describe a patient with CMT1B with focally folded myelin, a rarely reported phenotype of CMT1B, who initially presented with multiple entrapment neuropathies. She complained of palmar dysesthesia on both sides and on both soles of her feet in her 30’s. She underwent bilateral carpal and tarsal tunnel release at age 44, which provided transient relief from the symptoms. A sural nerve biopsy performed at age 49 revealed focally folded myelin. Molecular genetic analysis revealed a novel Asn131Ser mutation in MPZ.

High-Resolution MR Neurography: Evaluation Before Repeat Tarsal Tunnel Surgery

The purpose of this study was to retrospectively determine the accuracy of high-resolution MR neurography (MRN) in presurgical evaluation before repeat tarsal tunnel surgery. Ten MRN studies of nine patients (one man, eight women; mean age, 44.4 years; range, 23-67 years) who had been referred to a peripheral nerve specialist because of persistent symptoms after tarsal tunnel release were reviewed. The MRN findings studied included presence and location of focal fibrosis, presence or absence of nerve abnormality, location of nerve abnormality, and presence of neuroma formation and regional muscle denervation. The diagnostic accuracy of MRN in detection of posterior tibial nerve, medial plantar nerve, and lateral plantar nerve injury was calculated with clinical and intraoperative findings as the reference standards. Nine of 10 MRN studies (90%) had findings of nerve reentrapment related to focal fibrosis. Injured nerves were reliably visualized with MRN in all patients. MRN had a sensitivity of 77% for posterior tibial nerve, 100% for medial plantar nerve, and 100% for lateral plantar nerve injury, and the overall accuracy was 86%. The sensitivity of MRN was 91% for the presence of focal fibrosis affecting the three nerves and 67% for neuroma detection. Regional muscle denervation was better evaluated on MRN studies than at surgery. Smaller (1-3 mm) abnormal cutaneous nerve branches were better seen at surgery. MRN yields accurate morphologic information about the location and extent of nerve injury after failed tarsal tunnel release and facilitates preoperative diagnosis.