Tarsal Tunnel Research Articles

Reference values for distal motor conduction of the tibial nerve: Effects of demographic and anthropometric measures

In this study we collected reference values for the across-tarsal-tunnel conduction of the motor tibial nerve (mTN). The mTN compound muscle action potentials (CMAPs) from the abductor hallucis muscle were obtained by stimulating below/above the malleolus and the popliteal fossa. The effect of weight, height, body mass index (BMI), foot and leg length, sex, and age were evaluated using univariate and multivariate correlation analyses, and predictive equations for each mTN conduction parameter were developed. On the basis of data from 185 subjects, there were differences between women and men in all anthropometric parameters and for some nerve conduction values. Through multivariate analysis, age, but not sex, was found to have a significant impact. Height affected both distal and proximal conduction velocity. BMI affected CMAP amplitude. mTN conduction is influenced by various demographic and anthropometric factors. For all intrinsic factors, height demonstrated the greatest effect on mTN conduction across the tarsal tunnel.

Diagnostics and treatment of tunnel neuropathies

Relevance. Tunnel neuropathy – a damage of the peripheral nervous system that are common and range from 8 to 52 % of all diseases of the nervous system. Objective. To show the main features of the diagnosis and treatment of various tunnel neuropathy.Materials and Methods. Considerable experience of effective surgical treatment of tunnel neuropathies. 481 operations were performed during 2014–2019. The experience is described and structured.Results. The most common tunnel neuropathy of the upper extremity: carpal tunnel syndrome, pronator teres syndrome, cubital tunnel syndrome, Guyon's canal syndrome, radial neuropathy, thoracic outlet syndrome. Lower extremity: tarsal tunnel syndrome, Bernhardt – Roth syndrome, neuropathy of the peroneal nerve and its superficial branch. From 6.7 % to 78 % of patients with tunnel neuropathies, double crush syndrome occurs – nerve compression at two levels, which is more common in patients with diabetes mellitus. Such diseases are diagnosed clinically and instrumentally – electromyography, ultrasound, MRI. All the above pathologies are effectively treated surgically, which aims at decompression of the affected nerve. An important factor in complex treatment is early rehabilitation and physiotherapy procedures.Conclusions. Tunnel neuropathy is a common pathology that is effectively treated surgically. Diseases should be timely diagnosed to prevent severe and irreversible changes.

Dimensional Changes of the Tarsal Tunnel During Foot and Ankle Positions: Anatomical Study

The tarsal tunnel is a fibrous osseous conduit for the tibial nerve and associated tendons. It is mechanically dynamic, and foot and ankle movements appear to move and change tunnel shape. However, the effect of foot and ankle movements is not clear. The aim of this study was to measure tarsal tunnel dimensions in anatomical position of the foot and ankle and quantify its changes at different positions in cadavers. A cross-sectional study with a total of 16 cryopreserved lower extremities from cadaveric specimens were used. The foot was cut using an anatomical saw at the level of the tarsal tunnel. Measurements of the cross-sectional area (CSA), transverse diameter (TD), longitudinal diameter (LD) were taken in anatomical position and during foot and ankle movements. All the tarsal tunnel measurements were significantly modified by ankle plantar flexion (p < .05). The CSA increased by 68.97 mm2 (p < .001), the TD increased by 1.40 mm (p < .002) and the LD increased by 2.55 mm (p < .007). The TD was also significantly modified by the inversion position of the ankle, showing an increase of 0.84 mm (p < .004). The rest of the ankle positions did not produce significant changes in tarsal tunnel measurements. Foot and ankle plantar flexion position produce and increase in the CSA and the TD of the tarsal tunnel at its distal end in cadavers. This could suggest a reduction in tarsal tunnel pressure during plantar flexion.

Endoscopic Approach to Posterior Ankle via Lateral Portals

Posterior ankle pain is a common foot and ankle problem faced by orthopaedic surgeons. It can have many causes, including posterior ankle joint pathologies (synovitis or osteochondral lesion), ankle impingement (posterior, posterolateral, or posteromedial), flexor hallucis longus pathologies, peroneal tendon problems, posterior tibial tendinopathy, Achilles tendon pathology, posterior subtalar tarsal coalition, or tarsal tunnel syndrome. Most of these pathologies can be managed effectively by an endoscopic approach. The classic endoscopic approach is the 2-portal posterior ankle endoscopy with the portals at the medial and lateral side of the Achilles tendon. This is performed with the patient in prone position. In this technical note, we describe the details of endoscopic approach to the posterior ankle via lateral portals. This allow flexibility of patient positioning (supine, prone, or lateral). It is particularly effective for the management of posteromedial ankle impingement without the risk of injury to the posterior tibial neurovascular bundle. Moreover, any concomitant peroneal tendon pathology can be managed via the same lateral portals.

Analysis of Surgical Cases of Tarsal Tunnel Syndrome in Our Department: Case Series and Literature Review.

Background:Tarsal tunnel syndrome (TTS) is an entrapment neuropathy in which the tibial nerve is compressed within the tarsal tunnel and causes sensory disturbance in the sole of the foot. In this manuscript, we summarized our early surgical cases of TTS.Materials and Methods:Six feet in five patients with TTS were treated surgically. The patients were aged 31–70 years (mean 53.1 years), and all of them complained of pain or dysesthesia of the sole of the foot sparing the heel. Magnetic resonance imaging (MRI) and nerve conduction test were performed preoperatively. In surgery, flexor retinaculum was dissected (tarsal tunnel opening [TTO]), the posterior tibial nerve was freed from the arteriovenous complex (neurovascular decompression [NVD]), and fascia of the abductor hallucis muscle was excised to decompress the medial and lateral plantar nerve (releasing fascial of abductor hallucis muscle [RFAH]).Results:Preoperative MRI confirmed that all seven cases were idiopathic TTS. Moreover, NCD demonstrated delayed sensory conduction velocity but not delayed distal motor latency. Surgical decompression was beneficial in 5 feet. The recurrence of symptoms was found in one case within 1 postoperative month.Conclusion:Surgical treatment for idiopathic TTS with TTO, NVD, and RFAH was generally good. However, symptoms recurred in one instance. Some methods to prevent adhesion and granulation in the reconstructed tarsal tunnel should be considered.

Injection Techniques for Common Chronic Pain Conditions of the Foot: A Comprehensive Review.

Purpose of ReviewThis is a comprehensive literature review of the available evidence and techniques of foot injections for chronic pain conditions. It briefly describes common foot chronic pain syndromes and then reviews available injection techniques for each of these syndromes, weighing the available evidence and comparing the available approaches.Recent FindingsFoot and ankle pain affects 20% of the population over 50 and significantly impairs mobility and ability to participate in activities of daily living (ADLs), as well as increases fall risk. It is commonly treated with costly surgery, at times with questionable efficacy. Injection therapy is challenging when the etiology is anatomical or compressive. Morton’s neuroma is a budging of the interdigital nerve. Steroid, alcohol, and capsaicin injections provide some benefit, but it is short lived. Hyaluronic acid (HA) injection provided long-term relief and could prove to be a viable treatment option. Achilles tendinopathy (AT) is most likely secondary to repeat tendon stress—platelet-rich-plasma (PRP) and prolotherapy have been trialed for this condition, but more evidence is required to show efficacy. Similar injections were trials for plantar fasciitis and achieved only short-term relief; however, some evidence suggests that PRP injections reduce the frequency of required therapy. Tarsal tunnel syndrome, a compressive neuropathy carries a risk of permanent neural injury if left untreated. Injection therapy can provide a bridge to surgery; however, surgical decompression remains the definitive therapy. When the etiology is inflammatory, steroid injection is more likely to provide benefit. This has been shown in several studies for gout, as well as osteoarthritis of the foot and ankle and treatment-refractory rheumatoid arthritis. HA showed similar benefit, possibly due to anti-inflammatory effects. Stem cell injections may provide the additional benefit of structure restoration.SummaryChronic foot pain is common in the general population and has significant associated morbidity and disability. Traditionally treated with surgery, these are costly and only somewhat effective. Injections provide an effective alternative financially and some evidence exists that they are effective in pain alleviation. However, current evidence is limited and the benefit described from injection therapy has been short-lived in most cases. Further studies in larger populations are required to evaluate the long-term effects of these treatments.

Ultrasound-Guided Proximal and Distal Tarsal Decompression: An Analysis of Pressures in the Tarsal, Medial Plantar, and Lateral Plantar Tunnels.

Objectives. To analyze the reliability of measurements of tarsal tunnel and medial and lateral plantar tunnel pressures before and after ultrasound-guided release. Measurements taken were guided by ultrasound to improve reliability. This novel approach may help surgeons make surgical decisions. The second objective was to confirm that decompression using ultrasound-guided surgery as previously described by the authors is technically effective, reducing pressure to the tarsal and medial and lateral plantar tunnels. Methods. The study included 23 patients with symptoms compatible with idiopathic tarsal tunnel syndrome (TTS). The first step was to measure intracompartmental pressure of the tarsal tunnel, medial plantar tunnel, and lateral plantar tunnel preoperatively. The second step was ultrasound-guided decompression of the tibial nerve and its branches. Subsequently, pressure was measured again immediately after decompression in the 3 tunnels. Results. After surgery, the mean values significantly dropped to normal values. This represents a validation of effective decompression of the tibial nerve and its branches in TTS with ultra-minimally invasive surgery. Conclusions. The ultrasound-guided surgical technique to release the tibial nerve and its branches is effective, significantly reducing pressure in the tunnels and, thereby, decompressing the nerves.Level of evidence: Level IV.

The natural history of tarsal tunnel syndrome in diabetic subjects

Tibial nerve entrapment is highly prevalent in diabetic subjects, resulting in significantly more neuropathic complaints and concomitant sensory disturbances. The study aim was to assess the impact of tarsal tunnel syndrome (TTS) and sensory loss at baseline on incident diabetic foot ulceration (DFU) in diabetic patients, since decompressing the tibial nerve might change the natural history of the disease. In this study, 113 subjects with TTS (69 bilateral, 23 left-sided and 21 right-sided) participating in the prospective Rotterdam Diabetic Foot Study were compared to 303 diabetic controls without TTS, regarding incident DFU. Kaplan-Meier analysis and Cox's regression analysis were used to determine the independent hazard of baseline variables for new DFU. The median observation period was 836.5 days (IQR, 459-1077.8). In bilateral TTS, 17.4% (95% CI: 8.4-26.3%) of subjects experienced DFU versus 8.3% (95% CI: 5.1-11.6%) in controls (left or right) during follow-up (p = 0.0036). In left-sided TTS, no subjects versus 6.2% (95% CI: 3.4-9.0%) in controls had DFUs (p = 0.243). Incident ulceration was seen in 14.3% (95% CI: -0.7% to -29.3%) of right-sided TTS subjects versus 4.1% (95% CI: 1.5-6.3%) in controls (p = 0.034). Besides HbA1c, diminished sensation at the hallux independently increased the risk of ulceration, in patients with (HR: 4.692, p = 0.003) and without (HR: 2.307, p = 0.002) prior DFU. Elevated sensory thresholds in TTS render diabetic patients at a higher risk for DFU. With effective surgery, TTS is likely to be an amenable factor to potentially prevent diabetic foot disease and thereby reduce amputation risk. II.

Results of ultrasound-guided release of tarsal tunnel syndrome: a review of 81 cases with a minimum follow-up of 18 months

BackgroundThis study aims to analyse the clinical results of ultrasound-guided surgery for the decompression of the tibial nerve, including its distal medial and lateral branches, to treat tarsal tunnel syndrome. These structures are the complete flexor retinaculum and the deep fascia of the abductor hallucis muscle, including individualised release of the medial and lateral plantar nerve tunnels.MethodThis is a retrospective review of 81 patients (36 men and 45 women) with an average age of 41 years old (32–62) and an average clinical course of 31 months (8–96) compatible with idiopathic tarsal tunnel syndrome, who underwent ultrasound-guided decompression of the proximal and distal tarsal tunnel between February 2015 and November 2017 (both months included), with a minimum follow-up of 18 months.ResultsBased on the Takakura et al. scale for the 81 patients, 76.54% obtained excellent results, 13.58% good results, and 9.87% poor results.The patients with the longest course of symptoms displayed the worst results.ConclusionAlthough 9% of patients did not improve, ultrasound-guided tarsal tunnel release might be a viable alternative to conventional open approaches.

The injection site in the tarsal tunnel to minimize neurovascular injury for heel pain: an anatomical study.

The aim of this study was to investigate the location and distribution patterns of neurovascular structures and determine the effective injection point in the tarsal tunnel for heel pain. Fifteen adult non-embalmed cadavers with a mean age of 71.5 years were studied. The most inferior point of the medial malleolus of the tibia (MM) and the tuberosity of the calcaneus (TC) were identified before dissection. A line connecting the MM and TC was used as a reference line. The reference point was expressed in absolute distance along the reference line using the MM as the starting point. For measurements using MRI, the depth from the skin was measured to inferior at an interval of 1 cm from the MM. The posterior tibial artery, lateral plantar nerve, and medial plantar nerve were located from 29.0 to 37.3% of the reference line from the MM. The distribution frequencies of the medial calcaneal nerve on the reference line from the MM were 0%, 8.60%, 37.15%, 37.15%, and 17.10%, respectively. The mean depth of the neurovascular structures was 0.3 cm. This study recommended an effective injection site from 45.0 to 80.0% of the reference line.

Konieczność zastosowania metod mikrochirurgicznych i monitoringu śródoperacyjnego w patologii kanału stępu. Technika zabiegu

Konieczność zastosowania metod mikrochirurgicznych i monitoringu śródoperacyjnego w patologii kanału stępu. Technika zabiegu

Post-burn tarsal tunnel syndrome response to extracorporeal shock wave therapy

IntroductionTo evaluate the effect of extracorporeal shock wave therapy (ESWT) on electrophysiological responses in patients suffering from tarsal tunnel syndrome after burnMethodsOverall, 40 male and female individuals with tarsal tunnel syndrome after a burn injury were equally divided into 2 groups. Group 1 received ESWT in addition to a routine physical therapy program, which consisted of stretching of calf muscles followed by pulsed ultrasound, ice massage, and ankle pump exercise. Group 2 received the routine physical therapy program only. The area of popliteal fossa (slightly laterally) was outlined and 100 impulses per cm2 and another 100 impulses per cm2 were administered over the area behind and above the medial malleolus. The 2 areas were administered every 2 weeks for 3 months as a total period of treatment. Sensory and motor nerve conduction velocities of the lateral and medial plantar branches of the tibial nerve were measured before the treatment and after 3 months.ResultsThere was an improvement and a significant decrease in the prolonged motor and distal latencies of the 2 branches of the posterior tibial nerve in the ESWT group compared with group 2 (&lt;i&gt;p&lt;/i&gt; &lt; 0.05).ConclusionsESWT is effective in treating patients suffering from tarsal tunnel syndrome after burn as evidenced by decreasing the prolonged motor and sensory distal latencies of the 2 branches of the posterior tibial nerve

Inferior heel pain

Inferior heel pain affects up to 10% of the population. There are multiple pathologies and these can be considered by the anatomical structure affected (i.e. bone, nerve, ligamentous and other soft tissues). The most common pathology is in ligamentous and soft tissue. The plantar fascia may be degenerate (fasciosis), torn or enthesopathic, or there may be peri-fascial oedema. Soft tissue conditions include heel pad bruising and atrophy and tumours. Neurological causes are probably the next most common and include tarsal tunnel syndrome, nerve to abductor digiti quinti neuropathy, medial calcaneal neuropathy and lumbo-sacral radiculopathy. Bony pathologies include calcaneal stress fracture, calcaneal bone marrow oedema, tumours and osteomyelitis. The presenting features of each of these conditions are discussed, followed by the treatment options. The multitude of modalities used to treat plantar fascia-related pain are discussed in greater detail. The management of inferior heel pain involves a careful history and clinical examination. Not all heel pain is simply related to the plantar fascia. Without considering the other potential sources of pathology for which treatments may be markedly different, the clinician may easily unwittingly discount these. It is therefore incumbent to be clinically prudent, having a logical approach to assessment and diagnosis, prior to embarking on an appropriate course of treatment.

Coccydynia relieved by a tarsal tunnel block: a case series

BackgroundThis case series describes, for the first time, to the author’s knowledge, a novel treatment for coccydynia. Tarsal tunnel block with lignocaine only brought relief of chronic coccydynia lasting more than 6 months in three patients. The author adopts the theory that the myelin sheath of the posterior tibial nerve will convey the lipid-soluble lignocaine upward toward the dorsal root ganglia and the nerve roots of the lumbar spine through the uninterrupted myelin sheath, which is itself mainly formed of lipids. The author thinks that most coccyx pain is actually a radiating pain from the lumbar spine, which is not always apparent on magnetic resonance imaging of the lumbar spine. Certainly, the author acknowledges that large-scale studies need to be done to prove the efficacy of this new technique and to prove that the myelin sheath can convey the lignocaine chemical upward.Case presentationThree Arab patients presented with chronic coccydynia of more than 6 months’ duration in whom conservative management had failed to control their symptoms. They had no past medical history of significance and no history of trauma. The results of physical examination of all of the patients were normal apart from tenderness on palpation of the coccyx. They all received local coccyx injection with steroids on two occasions, which failed to relieve their pain. One patient underwent manipulation under anesthesia, and one underwent coccygectomy with no pain relief. Magnetic resonance imaging results were reported to be normal in two of them, whereas the other one had a prolapsed disc at the L4/L5 level. The three patients described pain relief 30 minutes after tarsal tunnel block with lignocaine only lasting more than 6 months. All patients had heel anesthesia 15 minutes after the tarsal tunnel injection, which lasted only 1 hour.ConclusionsTarsal tunnel block with lignocaine can relieve coccyx pain for a long time. Tarsal tunnel block can be done to achieve heel anesthesia before injection of lignocaine into the plantar fascia in patients with plantar fasciitis.

PO 18239 - Malerba Z-type osteotomy for the treatment of adult acquired flatfoot deformity

Introduction: Adult acquired flat foot deformity (AAFD) is a condition characterized by tendon and ligament failure that leads to progressive midfoot collapse and to hindfoot valgus. Calcaneal osteotomies are among the oldest and most conventional procedures for the treatment of angular limb deformities; they aim to reestablish the alignment and the line of action vector of the triceps surae muscle. Various disadvantages of classic osteotomies have been established in recent years, such as fixation loss, insufficient correction and reduced tarsal tunnel volume. Malerba Z-type osteotomy aims to resolve possible complications resulting from the usual incisions, to enhance the procedure and to allow multiplane corrections. Objective: To describe the functional and radiographic outcomes of Malerba Z-type osteotomy in patients with AAFD subjected to reconstructive surgery. Methods: Ten patients diagnosed with AAFD, with a mean age of 45 years (35-55), were operated on from January 2017 to January 2018. All patients underwent weight-bearing radiographs and alignment measurements and functional assessment using the pain visual analog scale (VAS) and the American Orthopedic Foot and Ankle Society (AOFAS) scale preoperatively and at the final evaluation at a mean of 12 months (6-18 months) after surgery. Results: The 10 patients showed positive progression after the surgery, reporting no major complications. Only one case of superficial dehiscence and one case of transient sural nerve neuropraxia (in different patients) were observed. On average, the AOFAS score increased by 50 points on average (25.7 to 76.6), and the VAS score decreased by 4 points (8.3 to 3.4). The mean calcaneal pitch increased from 5.5° to 15.2°. Nine patients transitioned from valgus malalignment (hindfoot angle greater than 10°) to the physiological (5 to 10° valgus) range. Conclusion: Ankle-foot realignment is an essential condition for surgical success in AAFD; it promotes a soft-tissue healing environment while maintaining an adequate muscle line of action. Malerba Z-type osteotomy was found to be a safe technique with high potential for deformity correction, leading to functional and radiographic improvement in patients who undergo this surgery.

Dimensional Changes of the Tibial Nerve and Tarsal Tunnel in Different Ankle Joint Positions in Asymptomatic Subjects

The tarsal tunnel is a clinically important fibrous osseous conduit for the tibial nerve and associated tendons. It is mechanically dynamic, and normal ankle movements appear to change the tunnel shape, potentially having an impact on the tibial nerve. The objective of this study was to measure changes in the tibial nerve and tarsal tunnel dimensions in plantarflexion and dorsiflexion of the ankle joint in healthy subjects. A cross-sectional study with 13 volunteer subjects and a total of 18 records was designed. The cross-sectional area, anterior-posterior distance, transverse distance, and flattening ratio of the tibial nerve were measured by using ultrasound in plantarflexion and dorsiflexion of the ankle joint. The anterior-posterior distance of the tarsal tunnel was also measured. The tunnel anterior-posterior distance significantly increased during plantarflexion (p < .001) and decreased during dorsiflexion (p = .027) of the ankle. From plantarflexion to dorsiflexion of the ankle, the tibial nerve cross-sectional area significantly decreased (p = .035). The anterior-posterior distance also decreased significantly (p < .001), whereas the transverse distance increased (p < .001), thus decreasing the flattening ratio of the tibial nerve (p < .001). Ankle joint position determined significant changes in the shape and dimensions of the tibial nerve at the tarsal tunnel.

Intraoperative Nerve Monitoring for Tarsal Tunnel Decompression: A Surgical Technique to Improve Outcomes

The aim of the current study was to evaluate the effectiveness of intraoperative neuromonitoring (INM) as an adjunct in performing tarsal tunnel decompression surgery. We reviewed 38 patients who met inclusion criteria. INM was used to measure the voltage of the abductor hallucis and digiti quinti muscles both before and after decompression. Observed changes intraoperatively were acute and within minutes of the decompression performed by the surgeon. Patient outcomes were ascertained from clinical findings and classified as excellent, fair, or poor. Patient outcomes and the voltage change were measured and assessed for association, and statistically significant differences were found between outcome groups. Of the 38 patients, 29 (76%) had excellent outcomes, with a mean change in microvolts of 2088.28 ± 1172.44 (684%) (p = .0004) and 2173.24 ± 1228.39 (742%) (p = .0014) for abductor hallucis and abductor digiti quinti, respectively. The study supports INM as a useful adjunct in performing tarsal tunnel decompression.

Clinical Outcomes of Percutaneous Plantar Fasciotomy Using Microdebrider Coblation Wand.

Plantar fasciitis is the most common cause of heel pain in adults. Multiple conservative treatment plans exist; however, some cases do not obtain significant clinical improvement with conservative treatment and require further intervention. This retrospective case study evaluated the success rate of percutaneous plantar fasciotomy and confounding comorbidities that negatively affect outcomes. A series of 41 patients treated with percutaneous plantar fasciotomy using the Topaz EZ microdebrider coblation wand were invited to participate in this retrospective follow-up study, and 88% (N = 36) participated. A limited chart review was completed and the patients answered a survey with the visual analog scale (VAS) for pain and the Foot and Ankle Ability Measure (FAAM) questionnaire. Average outcomes were calculated and 45 variables were analyzed to determine if they were statistically significant confounders. Patients had symptoms for an average of 3 years before the procedure and were contacted for follow-up at an average of 14 months after the procedure. The average VAS for pain score was 1.3 ± 1.8 and the average FAAM score was 92 ± 15. Eighty-nine percent of patients had a successful outcome, defined as FAAM greater than 75. In addition, patients at 18 months postprocedure reported complete or near-complete resolution of symptoms with an FAAM score greater than 97. Concurrent foot pathologies (eg, tarsal tunnel syndrome), oral steroid treatment prior to the procedure, and immobilization with a boot prior to the procedure were statistically significant negative confounders (P < .05). Being an athlete was a positive confounder (P = .02). Percutaneous plantar fasciotomy using a microdebrider coblation was an effective treatment for plantar fasciitis, particularly without concurrent foot pathology, with a low risk of complications. Level IV, retrospective case series.

The Effect of Calcaneal Displacement Osteotomies on Tarsal Tunnel Pressures

Category:Basic Sciences/BiologicsIntroduction/Purpose:Calcaneal displacement osteotomies are frequently utilized procedures to correct hindfoot varus and valgus deformities and are frequently used in conjunction with other procedures to restore normal alignment of the foot.Complications associated with this procedure include overcorrection, undercorrection, iatrogenic fracture, wound dehiscence, and infection. Additionally, neurologic deficit associated with lateralizing calcaneal osteotomy has been documented in the literature. Changes in ankle alignment have been shown to significantly alter tarsal tunnel pressure and volume, and a MRI study by Bruce et. al showed that lateral osteotomy fragment displacement results in significant reduction of tarsal tunnel volume. We hypothesized that a lateral displacement calcaneal osteotomy would result in an increase in tarsal tunnel pressure compared baseline tarsal tunnel pressures or those with a medial displacement calcaneal osteotomy.Methods:We performed cadaveric dissections on five foot and ankle cadavers. The laciniate ligament covering the tarsal tunnel was visualized at 2 cm proximal to the medial malleolus and a nick incision was made to insert the ICP monitoring probe; the tunnel was left intact distally. A 45 degrees lateral incision was made in line with the osteotomy site and a calcaneal osteotomy was performed in line with the incision approximately 1 cm anterior to the attachment of the achilles tendon. A Codman ICP monitoring probe was then used to measure baseline tarsal tunnel pressure measurements prior to calcaneal displacement. The osteotomy was then displaced medially and laterally and fixed in place in place with a K-wire (Figure 1). Tarsal tunnel pressures were measured at 5 mm and 8 mm displacement in both directions.Results:Average tarsal tunnel pressures at baseline were 2.8 mmHg (range, 1-5 mmHg). Average tarsal tunnel pressures with 5 mm and 8 mm of medial calcaneal displacement were 1.0 mmHg (range, 0-4 mmHg) and 0.8 mmHg (range, 0-3 mmHg), and with lateral calcaneal displacement were 7.4 mmHg (range, 3-13 mmHg) and 14.4 mmHg (range, 10-22 mmHg). There was no significant difference in tarsal tunnel pressures with either 5 mm (p=.067) or 8 mm (P=.067) of medial calcaneal displacement compared to baseline. There was, however, a significant increase in tarsal tunnel pressures with both 5 mm (p=.039) and 8 mm (p=.001) of lateral calcaneal displacement compared to tarsal tunnel pressures at baseline and with 5 mm (p=.002) and 8 mm (p=.001) of medial calcaneal displacement.Conclusion:Tibial nerve palsy following lateral displacement calcaneal osteotomy has recently been shown to have an incidence as high as 34%. Osteotomies decreasing volume in the tarsal tunnel could cause iatrogenic compression of the tibial nerve. Based on the results of our study, displacing the calcaneus laterally increases the tarsal tunnel pressures on average five times above baseline tarsal tunnel pressures. Medial displacement, however, does not appear to have any significant effect on pressures within the tunnel. The findings in this study provide further clinical evidence in support of prophylactic tarsal tunnel release prior to performing a lateralizing calcaneal osteotomy.

The Effect of Medial Displacement Calcaneal Osteotomy on Tarsal Tunnel Volume

Category:HindfootIntroduction/Purpose:Tarsal tunnel volume is affected by position of the foot and the alignment of the ankle. Although medial displacement calcaneal osteotomy (MDCO) significantly alters the alignment of the hindfoot, the change of tarsal tunnel volume after this procedure has not yet been well documented. Therefore, authors investigated the volumetric change of tarsal tunnel after MDCO using Computed Tomography (CT) scan.Methods:This retrospective study involved 101 feet of 91 patients who underwent a MDCO at our institution from March 2016 to December 2018. We compared the tarsal tunnel volume from the preoperative and postoperative CT scan images under following protocols. On a sagittal scout image, the oblique axial plane was drawn parallel to the long axis of the calcaneus using talonavicular joint as a landmark. Serial oblique axial images were displayed using PACS (PathSpeed, GE Healthcare, Chicago, IL, USA) with both the soft tissue and the bone window settings. The volume of tarsal tunnel was evaluated from just distal to the tip of medial malleolus anterior colliculus to distance of 3 cm distal using 10 consecutive images by drawing the border of tarsal tunnel. The volume was calculated by adding 10 cross-sectional areas and then multiplying by 3 mm corresponding to slice thickness.Results:The mean preoperative and postoperative tarsal tunnel volume were 12229 mm3 (SD, 1842 mm3) and 12762 mm3 (SD, 1803 mm3), respectively. There was 4.6% (SD, 3.4%) of volume increase after MDCO (p <0.001). Results indicated high inter- and intraobserver reliability coefficients (r = 0.97, r = 0.98, respectively).Conclusion:MDCO increased the volume of tarsal tunnel. This finding might support clinicians performing MDCO as a conjunctive surgical option in treating patients with tarsal tunnel syndrome.