Frequent Sural Nerve Injury with Posterior Approach for Ankle Fracture Fixation.

INTRODUCTION: The purpose of this study was to report the incidence of iatrogenic sural nerve injury in a large, consecutive sample of surgically managed ankle fractures and to identify factors associated with sural nerve injury and subsequent recovery. We hypothesize that a direct posterior approach may be associated with higher risk of iatrogenic sural nerve injury. METHODS: A retrospective cohort study of 265 skeletally mature patients who sustained ankle fractures over a 2-year period was done. All were treated with open reduction and internal fixation of fractured malleoli. Patient, injury, and treatment features were documented. The presence (n = 26, 9.8%) of sural nerve injury and recovery of sural nerve function were noted. RESULTS: All 26 sural nerve injuries were iatrogenic, occurring postoperatively after open reduction and internal fixation. Patients who sustained sural nerve injuries had more ankle fractures secondary to motor vehicle collisions (23.1% versus 9.2%), more associated trimalleolar fractures (69.2% versus 33.9%), and more Orthopaedic Trauma Association/AO 44B3 fractures (57.7% versus 25.1%), all P < 0.05. A posterior approach to the posterior malleolus through the prone position was used in 20.4% of patients. All 26 of the sural nerve injuries (100%) occurred when the patient was placed prone for a posterior approach, P < 0.001. Therefore, 26 of the 54 patients (48%) treated with a posterior approach sustained an iatrogenic sural nerve injury. 62% of patients had full recovery of sural nerve function with no residual numbness, and patients with nerve recovery had fewer associated fracture-dislocations (23.1% versus 100%, P = 0.003). CONCLUSIONS: A posterior approach for posterior malleolus fixation was associated with a 48% iatrogenic sural nerve injury rate, with 62% recovering full function within 6 months of injury. Morbidity of this approach should be considered, and surgeons should be cautious with nerve handling. LEVEL OF EVIDENCE: Level III, Therapeutic.

Positional relationship between the Achilles tendon and sural nerve on ultrasound.

PURPOSE: This study sought to clarify the positional relationship between the Achilles tendon and sural nerve using ultrasound. METHODS: We studied 176 legs in 88 healthy volunteers. The positional relationship between the Achilles tendon and sural nerve at heights of 2, 4, 6, 8, 10, and 12 cm proximal from the calcaneus' proximal margin was investigated by distance and depth. Setting the X-axis (left/right) as the horizontal axis and Y-axis (depth) as the vertical axis against ultrasound images, we investigated the distance between the lateral margin of the Achilles tendon to the midpoint of the sural nerve on the X-axis. The Y-axis was split into four zones: the part behind the center of the Achilles tendon (AS), the part in front of the center of the Achilles tendon (AD), the part behind the Achilles tendon (S), and the part in front (D). We investigated the zones through which the sural nerve passed. We also studied any significant differences between the sexes and left/right legs. RESULTS: The mean distance on the X-axis was closest at 6 cm, with 1.1 ± 5.0 mm between them. The sural nerve's position on the Y-axis was such that at positions more proximal than 8 cm, the sural nerve ran through zone S in most legs and moved to zone AS through heights 2-6 cm. No parameters showed significant differences between the sexes or left/right legs. CONCLUSION: We presented the positional relationship between the Achilles tendon and sural nerve and suggested some measures to prevent nerve injury during surgery.

Achilles: Failed Acute Repair.

Acute Achilles tendon ruptures are commonly managed with surgical repair. This particular surgery is prone to rerupture, wound complications, deep vein thrombosis, and sural nerve injuries. In this chapter the authors discuss complications, how to avoid them, and ultimately how to manage complications with your patients.

Modified Spared Nerve Injury Surgery Model of Neuropathic Pain in Mice.

Spared nerve injury (SNI) is an animal model that mimics the cardinal symptoms of peripheral nerve injury for studying the molecular and cellular mechanism of neuropathic pain in mice and rats. Currently, there are two types of SNI model, one to cut and ligate the common peroneal and the tibial nerves with intact sural nerve, which is defined as SNIs in this study, and another to cut and ligate the common peroneal and the sural nerves with intact tibial nerve, which is defined as SNIt in this study. Because the sural nerve is purely sensory whereas the tibial nerve contains both motor and sensory fibers, the SNIt model has much less motor deficit than the SNIs model. In the traditional SNIt mouse model, the common peroneal and the sural nerves are cut and ligated separately. Here a modified SNIt surgery method is described to damage both common peroneal and sural nerves with only one ligation and one cut with a shorter procedure time, which is easier to perform and reduces the potential risk of stretching the sciatic or tibial nerves, and produces similar mechanical hypersensitivity as the traditional SNIt model.

An Anatomic Study of the Sural Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications.

BACKGROUND: The sural nerve (SN) is a sensory cutaneous nerve that is at risk of iatrogenic injury during surgery at the lateral ankle. Prior anatomic studies of the SN are limited primarily to cadaveric studies with small sample sizes. Our study analyzed a large cohort of magnetic resonance images (MRIs) of the ankle to obtain a more generalizable, in vivo sample of distal SN course. METHODS: A total of 204 3-tesla MRI studies of the ankle were analyzed. Three reviewers measured the distance from the SN to various landmarks including the distal tip of the lateral malleolus (DTLM) and the lateral border of the Achilles tendon (LBA). RESULTS: Mean vertical distance from SN to DTLM was 2.2 cm (range, 0.9-3.6 cm). Mean horizontal distance from SN to DTLM and to LBA at the level of DTLM was 1.7 cm (range, 0.8-3.0 cm) and 1.9 cm (range, 1.0-2.9 cm), respectively. Mean horizontal distance from SN to LBA at the level of superior Achilles tendon insertion onto the calcaneus (SAI) was 2.6 cm (range, 1.4-3.7 cm), and mean horizontal distance from SN to LBA at 5 cm above SAI was 0.9 cm (range, 0.4-1.8 cm). CONCLUSION: The variation in SN course observed in our study allowed us to propose "safe zones" for several surgical approaches including the extensile lateral approach to the calcaneus (ELAC), the sinus tarsi approach (STA), the direct lateral approach to the lateral malleolus (DLA), and the posterolateral approach to the ankle (PLA), which we hope will minimize iatrogenic injury to the SN. LEVEL OF EVIDENCE: Level IV, case series.

Ecografía para prevenir lesiones del nervio sural en la reparación del tendón de Aquiles. Estudio cadavérico / Ultrasound to prevent sural nerve injury in Achilles tendon repair. A cadaveric study

Introducción: Las técnicas mínimamente invasivas son las preferidas para tratar las roturas agudas del tendón de Aquiles. Representan una opción para evitar las complicaciones tegumentarias, y la lesión del nervio sural es uno de sus principales problemas. El objetivo de este estudio fue comprobar la utilidad de la ecografía para prevenir la lesión del nervio sural durante la reparación del tendón de Aquiles con técnicas percutáneas. materiales y métodos: Estudio en 12 piezas cadavéricas. Se recreó una lesión en el tendón de Aquiles 5 cm proximales de su inserción distal. En uno de los miembros del cadáver, se identificó el nervio sural o su vena satélite mediante ecografía. Se reparó el nervio sural por vía percutánea con dos agujas proximales y dos agujas distales a la lesión, y se representó el recorrido del nervio sural. En el miembro contralateral, no se identificó el nervio sural mediante ecografía. Se efectuó la reparación percutánea de las lesiones mediante la técnica de Ma y Griffith. Resultados: En el grupo ecográfico, no se identificaron lesiones del nervio sural. En el grupo de control, se observaron dos lesiones del nervio sural (p = 0,6). En todos los casos, la identificación del nervio sural mediante ecografía fue correcta. Conclusión: La asistencia ecográfica en el tratamiento percutáneo de las lesiones del tendón de Aquiles es un método eficaz y confiable para evitar las lesiones del nervio sural. Nivel de Evidencia: III

Introduction: Minimally invasive techniques are preferred to treat acute Achilles tendon ruptures. They represent an option to avoid integumentary complications, and sural nerve injury is one of its main problems. This study aims to verify the usefulness of ultrasound in preventing sural nerve injury during Achilles repair with percutaneous techniques. materials and methods: Study in 12 cadaveric pieces. We recreated an injury at the level of the Achilles tendon, 5 cm proximally to its distal insertion. In one of the cadaver limbs, the sural nerve and/or its satellite vein were identified by ultrasonography. We repaired the sural nerve percutaneously with two needles at the proximal level and two needles at the distal level of the lesion and represented the path of the sural nerve. In the contralateral limb, the sural nerve was not identified by ultrasound. We performed the percutaneous repair of the injuries using the Ma & Griffith technique. Results: In the ultrasound group, no sural nerve injuries were identified. In the control group, two sural nerve injuries were observed (p=0.6). In all cases, the identification of the sural nerve by ultrasound was correct. Conclusion: Ultrasound assistance in the percutaneous treatment of Achilles tendon injuries is an effective and reliable method to prevent sural nerve injuries. Level of Evidence: III

Sex-Dependent Reduction in Mechanical Allodynia in the Sural-Sparing Nerve Injury Model in Mice Lacking Merkel Cells.

Innocuous touch sensation is mediated by cutaneous low-threshold mechanoreceptors (LTMRs). Aß slowly adapting type I (SAI) neurons constitute one LTMR subtype that forms synapse-like complexes with associated Merkel cells in the basal skin epidermis. Under healthy conditions, these complexes transduce indentation and pressure stimuli into Aß SAI LTMR action potentials that are transmitted to the CNS, thereby contributing to tactile sensation. However, it remains unknown whether this complex plays a role in the mechanical hypersensitivity caused by peripheral nerve injury. In this study, we characterized the distribution of Merkel cells and associated afferent neurons across four diverse domains of mouse hind paw skin, including a recently described patch of plantar hairy skin. We also showed that in the spared nerve injury (SNI) model of neuropathic pain, Merkel cells are lost from the denervated tibial nerve territory but are relatively preserved in nearby hairy skin innervated by the spared sural nerve. Using a genetic Merkel cell KO mouse model, we subsequently examined the importance of intact Merkel cell-Aß complexes to SNI-associated mechanical hypersensitivity in skin innervated by the spared neurons. We found that, in the absence of Merkel cells, mechanical allodynia was partially reduced in male mice, but not female mice, under sural-sparing SNI conditions. Our results suggest that Merkel cell-Aß afferent complexes partially contribute to mechanical allodynia produced by peripheral nerve injury, and that they do so in a sex-dependent manner.SIGNIFICANCE STATEMENT Merkel discs or Merkel cell-Aß afferent complexes are mechanosensory end organs in mammalian skin. Yet, it remains unknown whether Merkel cells or their associated sensory neurons play a role in the mechanical hypersensitivity caused by peripheral nerve injury. We found that male mice genetically lacking Merkel cell-Aß afferent complexes exhibited a reduction in mechanical allodynia after nerve injury. Interestingly, this behavioral phenotype was not observed in mutant female mice. Our study will facilitate understanding of mechanisms underlying neuropathic pain.

Anatomic relationship of the sural nerve when performing Achilles tendon repair using the percutaneous Achilles repair system, a cadaveric study.

BACKGROUND: Minimally invasive techniques for Achilles tendon repair are increasing due to reports of similar rerupture rates using open and percutaneous techniques with fewer wound complications and quicker recovery with percutaneous methods. The goal of this study was to investigate quantitatively the relationship and risk of injury to the sural nerve during Achilles tendon repair when using the Percutaneous Achilles Repair System (PARS) (Arthrex®, Naples, FL), by recording the distance between the passed needles and the sural nerve as well identifying any direct violation of the nerve with needle passage or nerve entrapment within the suture after the jig was removed. The hypothesis of the study is that the PARS technique can be performed safely and without significant risk of injury to the sural nerve. METHODS: A total of five needles were placed through the PARS jig in each of 10 lower extremity cadaveric specimens using the proximal portion after simulation of a midsubstance Achilles tendon rupture. Careful dissection was performed to measure the distance of the sural nerve in relation to the passed needles. The sutures were then pulled out through the incision as the jig was removed from the proximal portion of the tendon and observation of the suture in relation to the tendon was documented. RESULTS: Of the 10 cadaveric specimens, none had violation of the sural nerve. Zero of the 50 (0%) needles directly punctured the sural nerve. In addition, upon retraction of the jig, all sutures were noted to reside within the tendon sheath with no entrapment of the sural nerve noted. CONCLUSION: This study demonstrated the variable course of the sural nerve and identifies the potential risk for sural nerve injury when using the PARS for Achilles tendon repair. However, this study provides additional evidence of safety from an anatomic standpoint that explains the outcomes demonstrated in the clinical trials. With this information the authors believe surgeons should feel comfortable they can replicate those outcomes while minimizing risk of sural nerve injury when the technique is used correctly.

Avaliação da termoablação com endolaser da veia safena parva com anestesia local / Evaluation of endolaser thermoablation of the small saphenous vein under local anesthesia

Resumo Contexto Na insuficiência venosa crônica (IVC), a veia safena parva (VSP) é afetada em 15% dos casos. A cirurgia convencional é a técnica padrão para o tratamento da insuficiência da VSP, sendo a lesão no nervo sural uma complicação bastante temida. O tratamento de termoablação com endolaser tende a ser um método cirúrgico que diminui complicações da terapia cirúrgica da IVC. Objetivos Avaliar os pacientes com IVC submetidos à terapia por endolaser da VSP ao menos 30 dias após o procedimento. Métodos Foram analisados 54 membros inferiores de 46 pacientes submetidos à terapia por endolaser 1470 nm, sob anestesia local, para o tratamento da IVC em um hospital terciário. Os pacientes foram avaliados no período pré-operatório, intraoperatório e pós-operatório de 30 dias, através da clínica, exame físico e achados ecográficos. Resultados Nos 54 membros inferiores submetidos ao tratamento, comparando-se o período pré-operatório e o 30º dia pós-operatório, houve diferença significativa (p < 0,003) na redução do diâmetro da VSP tratada (6,37 mm pré-operatório e 5,15 mm no 30º dia pós-operatório) (IC95% 4,58-5,72) e na melhora do escore de gravidade clínica venosa (VCSS) (média de 8,02 pré-operatório e 6,11 no 30º dia pós-operatório) (IC95% 5,01-7,21) (p < 0,02). Complicações pós-operatórias, como parestesia e flebite, estiveram presentes e foram diagnosticadas em cinco e três pacientes, respectivamente, sem significar alteração na qualidade de vida e nas atividades de rotina. Conclusões A técnica de termoablação com laser da VSP mostrou-se segura e eficaz na redução dos sintomas clínicos e na melhora da qualidade de vida.

Abstract Background The small saphenous vein (SSV) is affected in 15% of chronic venous insufficiency (CVI) cases. Conventional surgery is the standard technique for treatment of SSV insufficiency, but sural nerve injury is a complication of great concern. Endovenous laser ablation is a surgical technique for treatment of CVI that is considered likely to reduce morbidity and mortality. Objectives To evaluate patients with CVI undergoing endovenous laser ablation of the SSV at least 30 days after the procedure. Methods We analyzed 54 lower extremities in 46 patients scheduled for 1470-nm endovenous laser ablation under local anesthesia to treat CVI in a tertiary hospital. Patients were evaluated preoperatively, intraoperatively, and postoperatively over 30 days with clinical examination, physical examination, and ultrasound. Results In the 54 lower extremities treated, there was a significant difference (p < 0.003) in terms of reduction in the diameter of treated veins (6.37 mm preoperatively and 5.15 mm on the 30th postoperative day) and improvement in the venous clinical severity score (VCSS) (means of 8.02 preoperative and 6.11 on the 30th postoperative day) (95%CI, 5.01—7.21) (p < 0.02). Postoperative complications such as paresthesia and phlebitis were present and diagnosed in 5 and 3 patients, respectively, but did not affect their quality of life or routine activities. Conclusions Intravenous laser ablation of the SSV proved to be safe and effective for reducing clinical symptoms and improving quality of life.

A network approach to investigating the key microbes and stability of gut microbial communities in a mouse neuropathic pain model.

BACKGROUND: Neuropathic pain is an abnormally increased sensitivity to pain, especially from mechanical or thermal stimuli. To date, the current pharmacological treatments for neuropathic pain are still unsatisfactory. The gut microbiota reportedly plays important roles in inducing neuropathic pain, so probiotics have also been used to treat it. However, the underlying questions around the interactions in and stability of the gut microbiota in a spared nerve injury-induced neuropathic pain model and the key microbes (i.e., the microbes that play critical roles) involved have not been answered. We collected 66 fecal samples over 2 weeks (three mice and 11 time points in spared nerve injury-induced neuropathic pain and Sham groups). The 16S rRNA gene was polymerase chain reaction amplified, sequenced on a MiSeq platform, and analyzed using a MOTHUR- UPARSE pipeline. RESULTS: Here we show that spared nerve injury-induced neuropathic pain alters gut microbial diversity in mice. We successfully constructed reliable microbial interaction networks using the Metagenomic Microbial Interaction Simulator (MetaMIS) and analyzed these networks based on 177,147 simulations. Interestingly, at a higher resolution, our results showed that spared nerve injury-induced neuropathic pain altered both the stability of the microbial community and the key microbes in a gut micro-ecosystem. Oscillospira, which was classified as a low-abundance and core microbe, was identified as the key microbe in the Sham group, whereas Staphylococcus, classified as a rare and non-core microbe, was identified as the key microbe in the spared nerve injury-induced neuropathic pain group. CONCLUSIONS: In summary, our results provide novel experimental evidence that spared nerve injury-induced neuropathic pain reshapes gut microbial diversity, and alters the stability and key microbes in the gut.

The arthroscopic all-inside ankle lateral collateral ligament repair is a safe and reproducible technique.

PURPOSE: Neurovascular structures around the ankle are at risk of injury during arthroscopic all-inside lateral collateral ligament repair for the treatment of chronic ankle instability. This study aimed to evaluate the risk of damage to anatomical structures and reproducibility of the technique amongst surgeons with different levels of expertise in the arthroscopic all-inside ligament repair. METHODS: Twelve fresh-frozen ankle specimens were used for the study. Two foot and ankle surgeons with different level of experience in the technique performed the procedure on 6 specimens each. The repair was performed following a standardized procedure as originally described. Then, an experienced anatomist dissected all the specimens to evaluate the outcome of the ligament repair, any injuries to anatomical structures and the distance between arthroscopic portals and the superficial peroneal nerve (SPN) and sural nerve. RESULTS: Dissections revealed no injury to the nerves assessed. Mean distance from the anterolateral portal and the SPN was of 4.8 (range 0.0-10.4) mm. The mean distance from the accessory anterolateral portal to the SPN and sural nerve was of 14.2 (range 7.1-32.9) mm and 28.1 (range 2.8-39.6) mm, respectively. The difference between the 2 surgeons' groups was non-statistically significant for any measurement (mm). In all specimens both fascicles of the anterior talofibular ligament were reattached onto its original fibular footprint. The calcaneofibular ligament was not penetrated in any specimen. CONCLUSIONS: The all-inside arthroscopic lateral collateral ligament repair is a safe and reproducible technique. The clinical relevance of this study is that this technique provides a safe and anatomic reattachment of the anterior talofibular ligament, with minimal risk of injury to surrounding anatomical structures regardless of the level of experience with the technique.

The incision strategy for minimizing sural nerve injury in medial displacement calcaneal osteotomy: a cadaveric study.

BACKGROUND: The skin incision for medial displacement calcaneal osteotomy (MDCO) often damages the sural nerve. We aimed to identify the practical reference area in which the surgeon can incise the skin to minimize the injury of the sural nerve during MDCO. METHODS: The foot and ankles of 20 cadavers were dissected. The landmarks were the following four anatomical references: point A, the tip of the lateral malleolus; point B, the inferior margin of the calcaneus on the vertical line through point A; point C, the posteroinferior apex of the calcaneus; and point D, the lateral border of the Achilles tendon on the horizontal line through point A. The distances from the sural nerve to points A and B in the vertical direction (lines D1 and D2, respectively), to points A and C in the diagonal direction (lines D3 and D4, respectively), and to points A and D in the horizontal direction (lines D5 and D6, respectively) were measured. RESULTS: The median ratios of D1 to D1+D2, D3 to D3+D4, and D5 to D5+D6 were 0.34 (range 0.25 to 0.45), 0.23 (range 0.16 to 0.33), and 0.38 (range 0.26 to 0.50), respectively. CONCLUSIONS: The distance ratios according to easily identifiable references would be a more practical incision strategy for surgeons to minimize sural nerve injury in both open and minimally invasive/percutaneous MDCO.

Can sural nerve injury be avoided in the sinus tarsi approach for calcaneal fracture?: A cadaveric study.

There is no consensus regarding the references to determine the exact location of the skin incision to minimize iatrogenic sural nerve injury in the sinus tarsi approach for calcaneal fracture.The purpose of this cadaveric study was to describe the anatomical course of the sural nerve in relation to easily identifiable landmarks during the sinus tarsi approach and to provide a more practical reference for surgeons to avoid sural nerve injury.Twenty-four foot and ankle specimens were dissected. The bony landmarks used in the following reference points were the tip of the lateral malleolus (point A), lateral border of the Achilles tendon on the collinear line with point A (point B), posteroinferior apex of the calcaneus (point C), inferior margin of the calcaneus on the plumb line through point A (point D), and tip of the fifth metatarsal base (point E). After careful dissection, the distances of the sural nerve to points A and B in the horizontal direction (lines D1 and D2), points A and C in the diagonal direction (lines D3 and D4), points A and D in the vertical direction (lines D5 and D6), and points A and E in the diagonal direction (lines D7 and D8) were measured.The median ratio of D1 to D1+D2, D3 to D3+D4, D5 to D5+D6, and D7 to D7+D8 were 0.37 (range, 0.26-0.50), 0.23 (range, 016-0.33), 0.35 (range, 0.25-0.45), and 0.32 (range, 0.20-0.45), respectively.The distance ratios from this study can be helpful to avoid sural nerve injury during the sinus tarsi approach for calcaneal fractures. Established standard incision may have to be modified to minimize sural nerve injury.

Minimally Invasive Treatments of Acute Achilles Tendon Ruptures.

Achilles tendon rupture is a common injury to the lower extremity that requires appropriate treatment to minimize functional deficit. Available treatments of Achilles tendon ruptures include nonoperative, open surgical repair, percutaneous repair, and minimally invasive repair. Open surgical repair obtains favorable functional outcomes with significant potential for deep soft tissue complications, calling into question the value of open repair. Percutaneous repair is an alternative option with comparable functional results and minimal soft tissue complications; however, sural nerve injury is a complication. Minimally invasive Achilles repair offers optimal results with superior functional outcomes with minimal soft tissue complications and sural nerve injury.

Cobertura de lesões em pé e terço inferior da perna com retalho fasciocutâneo reverso da panturrilha (Carriquiry) / Coverage of the lower third of the limb and foot injuries using reverse sural fasciocutaneous flap described by Carriquiry

Introdução: Lesões no terço distal dos membros inferiores, com exposição de ossos, articulações, tendões e vasos sanguíneos, não são passíveis do uso de enxertos de pele. Isto ocorre porque o leito vascular é exíguo e pela pobre granulação das feridas, podendo apenas ser corrigidas com retalhos musculares, miocutâneos, fasciocutâneos ou transferência microcirúrgica. Métodos: O retalho em seu limite inferior é demarcado a partir de 5 cm acima dos maléolos. Superiormente, é marcado num comprimento suficiente para cobertura total da lesão. Realizada incisão em demarcação prévia, e elevados pele e tecido subcutâneo juntamente com a fáscia muscular. O nervo sural é preservado em seu leito original. A elevação do retalho se dá até o ponto inferior marcado (o pedículo). Neste ponto, o retalho é transposto numa angulação suficiente para alcançar a lesão. Resultados: Oito casos foram operados utilizando o retalho descrito. Todos apresentavam exposição de ossos e tendões em região distal da perna, dorso do pé ou ambos, nos quais foram utilizados o retalho fasciocutâneo reverso da perna com a técnica proposta por Carriquiry. Os casos apresentaram resultados estético e funcional satisfatórios. Conclusão: O retalho utilizado se presta à correção de lesões do terço inferior da perna e do pé. É relativamente fácil de ser confeccionado, com bom suprimento vascular, e não há perda funcional do leito doador.

Introduction: Skin grafts are not effective to cover lesions in the distal third of the lower limbs that expose the bones, joints, tendons, and blood vessels due to a limited vascular bed and poor granulation of the wounds. These lesions can only be corrected with microsurgical transfer or muscle, myocutaneous, or fasciocutaneous flaps. Methods: The lower border of the flap was marked 5 cm above the malleolus. The upper border was marked after providing sufficient length for complete coverage of the lesion. The incision was performed at the marked upper border, and the skin and subcutaneous tissue were elevated together with muscle fascia. The sural nerve was preserved in its original bed. The flap was lifted to the marked lower border (the pedicle). At this point, the flap was transposed at a sufficient angle to cover the lesion. Results: Eight cases of surgery were conducted using the flap described above. All cases had exposed bones and tendons in the distal region of the limb, back of the foot, or both, in which the reverse sural fasciocutaneous flap with the technique proposed by Carriquiry was used. The cases showed satisfactory esthetic and functional results. Conclusion: The used flap can correct lesions of the lower third of the limbs and foot. It is relatively easy to make, with good vascular supply, and there is no functional loss of the donor area.

Ankle fusion percutaneous home run screw fixation: Technical aspects and soft tissue structures at risk.

INTRODUCTION: The objective of this cadaveric study was to identify the number of attempts necessary for a perfect positioning of the ankle fusion home run screw and the neurovascular and tendinous structures at risk. METHODS: Eleven cadaveric limbs were used. Guidewires were percutaneously placed into the distal posterolateral aspect of the leg, under fluoroscopic guidance, with the ankle held in neutral position. Malpositioned guidewires were not removed and served as guidance for the following wires. The number of guidewires needed to achieve an acceptable positioning of the implant was noted. Neurovascular and tendinous injuries were assessed, and the shortest distance between the closest guidewire and the soft tissue structures was measured using a precision digital caliper. RESULTS: Mean number of guidewires needed to achieve acceptable positioning of the implant was 2.34 (SD 0.81, range 2-4). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon 5.35 mm (SD 2.74 mm); peroneal tendons 9.65 mm (SD 5.19 mm); posteromedial neurovascular bundle 12.78 mm (SD 7.14 mm). The sural bundle was in contact with the guide pin in 5/11 specimens (45.5%) and impaled in 3/11 specimens (27.3%). The average distance from the sural nerve bundle was 3.58 mm (SD 2.16 mm). CONCLUSIONS: The placement of percutaneous ankle fusion home run screws is technically demanding requiring multiple attempts for acceptable placement. Important tendinous and neurovascular structures are in close proximity to the guidewires. The sural bundle was either injured or in direct contact with the guide wire in approximately 73% of the cases. When using a home run screw, a mini-open approach is recommended. LEVEL OF EVIDENCE: Level V, cadaveric study.

The distance from the peroneal tendons sheath to the sural nerve at the posterior tip of the fibula decreases from proximal to distal.

PURPOSE: The aim of this study is to compare the distance from the peroneal tendons sheath to the sural nerve in different points proximally and distally to the tip of the fibula. METHODS: Ten fresh-frozen lower extremities were dissected to expose the nerves and tendons. Having the posterior tip of the fibula as a reference, the distance between the tendons sheath and the sural nerve was measured in each point with a tachometer with three independent different observers. Two measures were taken distally at 1.5 and 2 cm from fibula tip and 3 measures were performed proximally at 2, 3, and 5 cm from fibula tip. Data were described using means, standard deviations, medians, and minimum and maximum values. RESULTS: The average distance between distance between the fibula tip and sural nerve is 16.6 ± 4.4 mm. The average distance between peroneal tendons sheath and the sural nerve at 5 cm, 3 cm, and 2 cm from the proximal fibular tip was 29.6 ± 3.2 mm, 24.2 ± 3.6 mm, and 19.7 ± 2.7 mm, respectively. The average distance between the peroneal tendons sheath and the sural nerve at 2 cm and 1.5 cm distal to fibular tip was 9.1 ± 3.5 mm and 7.8 ± 3.3 mm, respectively. CONCLUSION: The distance from the peroneal tendons sheath to the sural nerve decreases from proximal to distal. As the distance between the peroneal tendons sheath and the sural nerve decreases from proximal to distal, performing the tendoscopy portal more distally would increase the risk of nerve iatrogenic injury.

A safe technique for insertion of heel wires for hindfoot external fixation frames: an anatomical study.

Aims: Anatomical atlases document classical safe corridors for the placement of transosseous fine wires through the calcaneum during circular frame external fixation. During this process, the posterior tibial neurovascular bundle (PTNVB) is placed at risk, though this has not been previously quantified. We describe a cadaveric study to investigate a safe technique for posterolateral to anteromedial fine wire insertion through the body of the calcaneum. Materials and Methods: A total of 20 embalmed cadaveric lower limbs were divided into two groups. Wires were inserted using two possible insertion points and at varying angles. In Group A, wires were inserted one-third along a line between the point of the heel and the tip of the lateral malleolus while in Group B, wires were inserted halfway along this line. Standard dissection techniques identified the structures at risk and the distance of wires from neurovascular structures was measured. The results from 19 limbs were subject to analysis. Results: In Group A, no wires pierced the PTNVB. Wires were inserted a median 22.3 mm (range 4.7 to 39.6) from the PTNVB; two wires (4%) passed within 5 mm. In Group B, 24 (46%) wires passed within 5 mm of the PTNVB, with 11 wires piercing it. The median distance of wires from the PTNVB was 5.5 mm (range 0 to 30). A Mann-Whitney U test showed that this was significantly closer than in Group A (Hodges-Lehmann shift, 14.06 mm; 95% confidence interval (CI) 10.52 to 16.88; p < 0.0001). In Group B, with an increased angle of insertion there was greater risk to the PTNVB (rs = -0.80; p < 0.01). Conclusion: Insertion of wires using an entry point one-third along a line from the point of the heel to the tip of the lateral malleolus (Group A) appears to be the safer technique. An insertion angle of up to 30° to the coronal plane can be used without significant risk to the PTNVB. Insertion of wires halfway along a line from the point of the heel to the tip of the lateral malleolus (Group B) carried a significantly higher risk of injury to neurovascular structures and, if necessary, an angle of insertion parallel to the coronal plane should be used. Cite this article: Bone Joint J 2018;100-B:1054-9.

Comparison of Anatomic Structures at Risk With 2 Lateral Lengthening Calcaneal Osteotomies.

BACKGROUND:: Lateral lengthening calcaneal osteotomies (LLCOT) are commonly used to treat flexible pes planovalgus deformity. Different operative techniques have been described. The aim of this study was to examine which anatomic structures were affected by 2 different osteotomy techniques. METHODS:: Two experienced foot and ankle surgeons each performed an Evans (E)- or Hintermann (H) osteotomy on 7 cadaver feet. The mean age of the donors was 80.4 ± 4.4 years. Eight left and 6 right feet were prepared. Previously identified structures at risk were prepared and evaluated. RESULTS:: After H-LLCOT, there was no damage of the peroneus longus tendon, whereas after E-LLCOT, damage was noted in 1 case (14.3%). The peroneus brevis tendon was once cut after H-LLCOT and eroded after E-LLCOT. In one cadaver, the sural nerve was partially damaged after H-LLCOT but in no case after E-LLOCT. The calcaneal anterior and medial articular facets were intact after H-LLCOT in 100% and 85.7% and after E-LLCOT in 42.9% and 71.4%, respectively. The posterior articular surface was not affected in any cadaver. CONCLUSION:: Anatomic structures can be damaged after both osteotomies. With the Hintermann osteotomy, the calcaneal anterior and medial articular surface can be protected to a larger extent than with the Evans osteotomy. CLINICAL RELEVANCE:: The Hintermann osteotomy seems to be superior, regarding damage of the articular surfaces of the subtalar joint. These findings have to be correlated with biomechanical and clinical studies before a final recommendation can be given, which osteotomy is superior.