An anatomical comparison of the fasciae of the thigh: A macroscopic, microscopic and ultrasound imaging study.

Although the number of Ultrasound (US) imaging studies investigating the fascial layers are becoming more numerous, the majority tend to use different reference points and terminology to describe their findings. The current work set out to compare macroscopic and microscopic data of specimens of the fascial layers of the thigh with US imaging findings. Specimens of the different fascial layers of various regions of the thigh were collected for macroscopic and histological analyses from three fresh cadavers and compared with in vivo US images of the thighs of 20 healthy volunteers. The specimens showed that the subcutaneous tissue of the thigh is made up of three layers: a superficial adipose layer, a membranous layer/superficial fascia, and a deep adipose layer. The deep fascia is composed of an aponeurotic fascia, which envelops all the thigh muscles and is laterally reinforced by the iliotibial tract and an epimysial fascia, which is specific for each muscle. The morphometric measurements of the thickness of the superficial fascia were different (anterior: 153.2 ± 39.3 µm; medial: 128.4 ± 24.7 µm; lateral: 154 ± 28.9 µm; and posterior: 148.8 ± 33.2 µm) as were those of the deep fascia (anterior: 556.8 ± 176.2 µm; medial: 820.4 ± 201 µm; lateral: 1112 ± 237.9 µm; and posterior: 730.4 ± 186.5 µm). The US scans showed a clear picture of the superficial adipose tissue, the superficial fascia, and the deep adipose tissue, as well as the deep fasciae. The epimysial and aponeurotic fasciae of only some topographic areas could be independently identified. The US imaging findings confirmed that the superficial and deep fascia have different thicknesses, and they showed that the US measurements were always larger with respect to those produced by histological analysis (p < 0.001) probably due to shrinkage during the processing. The posterior region (level 1) of the superficial fascia had, for example, a mean thickness of 0.56 ± 0.12 mm at US, while the histological analysis showed that it was 148.8 ± 33.2 µm. Showing a similar pattern, the thickness of the deep fascia was as follows: 1.64 ± 0.85 mm versus 730.4 ± 186.5 µm. Study results have confirmed that US can be considered a valid, non-invasive instrument to evaluate the fascial layers. In any event, there is a clear need for a set of standardised protocols since the thickness of the fascial layers of different parts of the human body varies and the data obtained using inaccurate reference points are not reproducible or comparable. Given the inconsistent terminology used to describe the fascial system, it would also be important to standardise the terminology used to define its parts. The difficulty in distinguishing between the epimysial and aponeurotic/deep fascia can also impede data interpretation.

Measurement of iliotibial band diameter in iliotibial band friction syndrome and comparison with an asymptomatic population.

BACKGROUND: Iliotibial band friction syndrome (ITBFS) is an overuse injury of the lateral aspect of the knee. This syndrome classically affects the active young population. PURPOSE: To determine the diameter of the ITB using magnetic resonance imaging (MRI) in patients clinically diagnosed with ITBFS, compare the results with asymptomatic patients, and assess the inter-observer agreement between a senior and a junior radiologist with different levels of experience in musculoskeletal imaging. MATERIAL AND METHODS: From April 2014 to October 2019, 78 knee MRI scans of 78 patients were included in the study group who were referred from the orthopedic clinic with a clinical diagnosis of ITBFS. In the control group, there were 114 knee MRI scans of 114 patients who had knee MRI for various reasons and had no radiological abnormality on the performed knee MRI. The ITB diameters, cut-off values, and interclass correlation coefficient (ICC) were calculated. RESULTS: Mean thickness of the ITB was higher in the study group compared to the control group in measurements done by both the senior and junior radiologists and this was statistically significant (P < 0.001). Cut-off values of the diameters of the ITB were calculated as 2.385 for the senior radiologist and 2.420 for the junior radiologist. ICC of 0.80 was determined, which showed excellent agreement among interpreters. CONCLUSION: ITB thickness in the study group was significantly higher than in the control group. There was also excellent agreement among the two observers. Measurement of ITB thickness on axial plane knee MRI is one of the reliable criteria for ITBFS.

A fluoroscopic analysis of the length changes of the capsulo-osseous layer of the distal iliotibial band.

PURPOSE: Previous studies have implicated the iliotibial band and its deeper capsulo-osseous layer as key restraints against internal rotation. However, the kinematic properties of the capsulo-osseous layer, throughout knee range of motion, are not currently known. Therefore, the purpose of this research was to quantify the length changes of this structure through various degrees of knee flexion. METHODS: Ten cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments, into the tissue and fluoroscopic images were taken from 0° to 105° of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. The data were analyzed as a percent change from 0° and compared across flexion angles using a repeated-measures analysis of variance (α = 0.05). RESULTS: There was a significant increase in the length of the capsulo-osseous layer at flexion angles greater than 30°, with changes occurring primarily at the level of the femoral insertion. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60° to 105°; maximal changes occurred at 105° [9.64 (4.12) %, p = 0.003]. CONCLUSIONS: The capsulo-osseous layer of the iliotibial band behaves in a non-isometric fashion and this work suggests that tensioning and fixation should occur between 75° and 105° of flexion, if repair or reconstruction is indicated.

Influence of female hormones on fascia elasticity: An elastography study.

The aim of this study was to examine the influence of hormonal changes during the menstrual cycle on deep fasciae. A total of 29 women, 17 users, and 12 nonusers of hormonal contraceptives were examined clinically and by ultrasound, including shear wave elastography, at two phases of the menstrual cycle. The thickness and elasticity of the fascia lata, thoracolumbar fascia, and plantar fascia were measured, compared between hormonal contraceptive users and nonusers, and correlated with clinical data. There were statistically significant differences between users and nonusers of hormonal contraceptives: the thoracolumbar fascia was thicker in nonusers (P = 0.011), and nonusers had higher maximal and mean stiffnesses of the fascia lata (P = 0.01 and 0.0095, respectively). Generally, nonusers had a higher body mass index (BMI). The elasticity of the thoracolumbar and the plantar fasciae did not differ significantly between the groups. We found no correlation between thickness and elasticity in the fasciae. There were no statistically significant differences in hypermobility, cephalgia, or dysmenorrhea between users and nonusers of hormonal contraceptives. The results of this pilot study suggest that deep fasciae can be evaluated by shear wave elastography. Nonusers of contraceptives had greater stiffness of the fascia lata and higher BMI. Clin. Anat. 32:941-947, 2019. © 2019 Wiley Periodicals, Inc.

High-resolution ultrasound of the fascia lata iliac crest attachment: anatomy, pathology, and image-guided treatment.

Pathology of the fascia lata attachment at the iliac crest (FLAIC) is an under-recognized and often misdiagnosed cause of lateral hip pain. The fascia lata has a broad attachment at the lateral iliac crest with contributions from the tensor fascia lata muscle, the iliotibial band, and the gluteal aponeurosis. The FLAIC is susceptible to overuse injuries, acute traumatic injuries, and degeneration. There is a paucity of literature regarding imaging and image-guided treatment of the FLAIC. We review anatomy and pathology of the FLAIC, presenting novel high-resolution (18-24 MHz) ultrasound images including ultrasound guidance for targeted therapeutic treatment.

Morphometric and dynamic measurements of muscular fascia in healthy individuals using ultrasound imaging: a summary of the discrepancies and gaps in the current literature.

PURPOSE: The objectives of this work was to conduct a comprehensive state-of-the art review of the current literature to identify any gaps or discrepancies and summarize the main challenges for obtaining a homogeneous evaluation of muscular fascia in healthy individuals. METHODS: An electronic document search using key words and MeSH terms was performed with various databases. Two independent investigators were tasked with the screening of articles and data extraction. A critical appraisal of what is known was then conducted. RESULTS: The literature search identified 65 articles related to healthy facia in the various databases consulted and 20 articles were kept for the review. The thickest portion of the fascia lata (the iliotibial tract) and the plantar fascia are the most often studied muscular fasciae whereas there is paucity of studies on fascia related to other muscles in the body. CONCLUSION: US imaging is suitable to complement physical examination and for evaluating treatment outcomes. However, the small number of studies and the heterogeneity of the methods did not allow us to establish normal reference values for muscular fascia thickness and to provide strong recommendations about measurement protocols.

Tratamento cirúrgico da ptose palpebral moderada e grave: análise de resultados / Surgical treatment of moderate and severe ptosis: analysis of results

Introdução: A ptose palpebral é uma afecção comum na prática clínica na qual uma perfeita avaliação torna-se mandatória. Definimos ptose quando a margem palpebral encontra-se abaixo de 2 mm da junção córneo escleral e pode ser classificada em leve, moderada e grave. Existem inúmeras técnicas de reparo e a escolha dependerá da classificação da função do músculo levantador. Métodos: Foram analisados de forma prospectiva, no período de março de 2013 a maio de 2015, quatorze (n = 14) pacientes submetidos ao tratamento cirúrgico de ptose palpebral moderada e grave (n = 21). Inúmeros fatores foram estudados, tais como grau de ptose e função do músculo elevador da pálpebra, tipo de técnica de reparo, complicações imediatas e tardias, etc. Resultados: Quatorze pacientes foram opera-dos, totalizando 21 pálpebras, sendo que, 85% foram de etiologia adquirida e 15% congênita. Com relação ao grau de ptose, 64,3% (n = 9) foram moderadas e 35,7% (n = 5) graves. No que tange à função do músculo levantador, encontramos função boa 28,5% (n = 4), moderada 28,5% (n = 4) e pobre 43% (n = 6). Em relação às com-plicações, 2 casos de hiperemia conjutival e um caso de edema. Obtivemos um alto índice de satisfação com 85,7% (n = 12), com baixas taxas de complicações. Conclusão: A ptose palpebral é uma enfermidade comum na prática clínica e exige por parte do cirurgião um perfeito conhecimento anatômico da delicada estrutura palpebral e também de sua fisiopatologia. Uma perfeita avaliação desse paciente torna-se mandatória para o emprego do tratamento mais adequado.

Introduction: Eyelid ptosis is a common condition in clinical practice for which a complete evaluation is mandatory. Ptosis is defined when the eyelid margin is 2 mm below the corneoscleral junction and can be classified as mild, moderate, and severe. There are numerous repair techniques, and the choice will depend on the classification of the function of the levator muscle. Methods: We evaluated prospectively, from March 2013 to May 2015, 14 patients who underwent surgical treatment of moderate and severe ptosis (n = 21). Several factors were studied, such as degree of ptosis and function of the eyelid levator muscle, type of repair technique, and immediate and late complications. Results: Fourteen patients (21 eyelids) underwent operation. The etiology was acquired in 85% of the cases and congenital in 15%. With respect to the degree of ptosis, 64.3% (n = 9) of the cases were moderate and 35.7% (n = 5) were severe. With respect to the muscle function of the levator, good, moderate, and poor functions were observed in 28.5% (n = 4), 28.5% (n = 4), and 43% (n = 6) of the cases, respectively. With regard to complications, 2 cases of conjunctival hyperemia and one case of edema were observed. We obtained a high satisfaction rate of 85.7% (n = 12), with low complication rates. Conclusion: Eyelid ptosis is a common presentation in clinical practice and requires on the part of the surgeon a detailed anatomical knowledge of the delicate structure of the eyelid and its pathophysiology. A complete evaluation of these patients is mandatory for the employment of the most appropriate treatment.

Morphometric properties of the tensor fascia lata muscle in human foetuses.

BACKGROUND: In neonatal and early childhood surgeries such as meningomyelocele repairs, closing deep wounds and oncological treatment, tensor fasciae lata (TFL) flaps are used. However, there are not enough data about structural properties of TFL in foetuses, which can be considered as the closest to neonates in terms of sampling. This study's main objective is to gather data about morphological structures of TFL in human foetuses to be used in newborn surgery. MATERIALS AND METHODS: Fifty formalin-fixed foetuses (24 male, 26 female) with gestational age ranging from 18 to 30 weeks (mean 22.94 ± 3.23 weeks) were included in the study. TFL samples were obtained by bilateral dissection and then surface area, width and length parameters were recorded. Digital callipers were used for length and width measurements whereas surface area was calculated using digital image analysis software. RESULTS: No statistically significant differences were found in terms of numerical value of parameters between sides and sexes (p > 0.05). Linear functions for TFL surface area, width, anterior and posterior margin lengths were calculated as y = -225.652 + 14.417 × age (weeks), y = -5.571 + 0.595 × age (weeks), y = -4.276 + 0.909 × age (weeks), and y = -4.468 + 0.779 × age (weeks), respectively. CONCLUSIONS: Linear functions for TFL surface area, width and lengths can be used in designing TFL flap dimensions in newborn surgery. In addition, using those described linear functions can also be beneficial in prediction of TFL flap dimensions in autopsy studies.

Anatomy of the pedicled anterolateral thigh flap for phalloplasty in transitioning-males.

Incidence of transexualism and request for neophalloplasty is increasing yielding a current prevalence of trans-male in the USA of 1:2500. Surgeons have explored various techniques to improve desirable outcomes of neophallic construction, decrease the length of surgery, and minimize stigmatizing scars. The anterolateral thigh (ALT) flap is an alternative to the traditional radial forearm flap for patients who do not want a forearm scar. Surgical text descriptions were enhanced by the creation of new anatomic illustrations. Anatomy of the donor and recipient sites as well as the surgical technique leading to creation of the neophallus are demonstrated in detail with new relevant illustrations. The ALT flap is a skin, fat and fascia flap that is usually supplied by the descending branch of the lateral circumflex femoral vessels and the lateral femoral cutaneous nerve. However, variability in neurovascular supply does exist with important clinical implications. In the pedicled surgical procedure, neurovascular supply is left partly attached to the donor site ("pedicle") and simply transposed to the perineum, keeping the pedicle intact as a conduit to supply the tissue with blood and innervation. ALT flap offers clinical advantages of less obvious donor site concealable with clothing, decreased surgical time, preservation of erogenous sensation and vascular supply of the flap without microsurgical anastomosis of nerves and vessels, and good potential for urethroplasty. This surgery may be difficult in patients with thicker skin and more subcutaneous thigh fat. Clin. Anat, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Deep and superficial circumflex iliac arteries and their relationship to the ultrasound-guided femoral nerve block procedure: A cadaver study.

The in-plane lateral to medial approach is a standard technique for ultrasound-guided femoral nerve block (USG-FNB). The first bifurcation of the femoral artery, which consists of the deep artery of the thigh (DAT) or occasionally the lateral circumflex femoral artery (LCFA), is regarded as the distal border for this procedure. We sometimes detect arteries along the estimated needle trajectory for USG-FNB. The superficial (SCIA) and deep (DCIA) circumflex iliac arteries run laterally parallel to the inguinal ligament from the femoral or external iliac artery. The relationship between the SCIA and DCIA and other anatomical structures related to USG-FNB around the femoral triangle region was studied by gross anatomical examination of 100 formalin-fixed adult cadavers. At least one SCIA and one DCIA were identified around each femoral triangle; 81.8% of SCIA and 58% of DCIA originated from the femoral artery. All DCIA coursed between the fascia lata and fascia iliaca and 80% of SCIA penetrated the fascia lata. In 94% of femoral triangles, at least one arterial branch heading towards the lateral part of the thigh originated from the femoral artery from the level of the inguinal ligament to the first bifurcation of the femoral artery. The presence of SCIA and DCIA should be considered during USG-FNB using the in-plane lateral to medial approach to avoid inadvertently injuring them, as they are occasionally located along the presumed needle trajectory superficial to the fascia iliaca. Clin. Anat. 30:413-420, 2017. © 2017 Wiley Periodicals, Inc.

The iliotibial tract: imaging, anatomy, injuries, and other pathology.

The iliotibial tract, also known as Maissiat's band or the iliotibial band, and its associated muscles function to extend, abduct, and laterally rotate the hip, as well as aid in the stabilization of the knee. A select group of associated injuries and pathologies of the iliotibial tract are seen as sequela of repetitive stress and direct trauma. This article intends to educate the radiologist, orthopedist, and other clinicians about iliotibial tract anatomy and function and the clinical presentation, pathophysiology, and imaging findings of associated pathologies. Specifically, this article will review proximal iliotibial band syndrome, Morel-Lavallée lesions, external snapping hip syndrome, iliotibial band syndrome and bursitis, traumatic tears, iliotibial insertional tendinosis and peritendonitis, avulsion fractures at Gerdy's tubercle, and Segond fractures. The clinical management of these pathologies will also be discussed in brief.

Morphological and histomorphometric evaluation of the ventral rectus sheath of the rectus abdominis muscle, fascia lata and pectoral fascia. The beginning of a morphological information bank of human fascias.

The aim of this study was to characterize and compare the morphological and histomorphometric characteristics of the pectoral fascia, fascia lata and ventral rectus sheath. Twenty cadaveric samples of these fascias were analyzed and stained with hematoxylin and eosin, orcein, Van Gieson, Masson's trichrome and Verhoeff¨s stain (1200 slides in total). Morphological evaluation, semiquantitative, morphometric and microdensitometric analysis of elastic fibers present in each of the tissues and a morphometrical analysis of tissue thickness were performed. The mean value of the pectoral fascia thickness was 612±68.13 µm; 84±246 µm for the fascia lata and 584±92 µm for the ventral rectus sheath. The area occupied by the elastic fibers in the pectoral fascia was 12.24±5.84%; 6,54±3.85% for the fascia lata and 11.11±5.26% for the ventral rectus sheath. There were no statistically significant differences when comparing the mean values between the pectoral fascia and the ventral rectus sheath (p=0.07). There were statistically significant differences when comparing the fascia lata to the pectoral fascia and the ventral rectus sheath (p≤0.001). This study reports other morphological characteristics not described in previous histological studies of the analyzed tissues. The results of the morphometric and densitometric analysis in this study reveal that the fascia lata has the fewest elastic fibers of all the tissues analyzed, and the pectoral fascia has the most. These results will be useful for the beginning of a morphological information bank of human fascias.

Structural Properties of the Anterolateral Capsule and Iliotibial Band of the Knee.

BACKGROUND: The role of the anterolateral capsule in knee stability has recently been advocated by studies reporting that a distinct ligament exists in this area. Defining the structural properties of the anterolateral capsule can provide insight into its contribution to joint stability. The structural properties of the iliotibial band also need to be determined, as it is a common graft used for extra-articular tenodesis. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the structural properties of the anterolateral capsule and iliotibial band. The hypothesis was that the iliotibial band will have comparable structural properties to the anterolateral capsule because it is generally an accepted graft for extra-articular reconstruction surgeries. STUDY DESIGN: Controlled laboratory study. METHODS: Nine human cadaveric knees (average age, 57 ± 10 years) were dissected to assess the presence of a discrete capsular thickness originating from the lateral femoral epicondyle to the lateral tibial plateau between the Gerdy tubercle and the fibular head. For each knee, 2 constructs were prepared: (1) a bone-anterolateral capsule-bone specimen and (2) a strip of iliotibial band attached to the Gerdy tubercle. Structural properties, including ultimate load, ultimate elongation, and stiffness, were determined for the anterolateral capsule and the iliotibial band. After tensile testing, plain radiographs were obtained for evaluation of the Segond fracture. A paired t test was used to compare the structural properties of the anterolateral capsule with the iliotibial band. Significance was set at P < .05. RESULTS: Two of the 9 specimens were found to have a discrete thickening of the anterolateral capsule. The iliotibial band had almost 50% higher ultimate load and nearly 3 times higher stiffness (487.9 ± 156.9 N and 73.2 ± 24.1 N/mm, respectively) compared with the anterolateral capsule (319.7 ± 212.6 N and 26.0 ± 11.5 N/mm, respectively) (P < .05 for both). The anterolateral capsule had about double the ultimate elongation compared with the iliotibial band (15.5 ± 7.3 and 8.6 ± 1.4 mm, respectively; P < .05). CONCLUSION: The anterolateral capsule demonstrated significantly reduced structural properties compared with the iliotibial band. The anterolateral capsule did not have a higher ultimate load compared with the posteromedial capsule as reported in the literature. CLINICAL RELEVANCE: The decision to perform an extra-articular reconstruction using an iliotibial band graft should be considered carefully. Unnecessary reconstructions using soft tissue grafts with structural properties that far exceed that of the anterolateral capsule may result in overconstraint of the ACL-reconstructed knee.

Anatomical study of the morphological continuity between iliotibial tract and the fibularis longus fascia.

PURPOSE: Recent research indicates that the skeletal muscles of the human body do not function as independent actuators. Instead, they seem to be linked by connective tissue forming myofascial chains. While the existence of such meridians has been demonstrated for the ventral and the dorsal side of the body, no data are available for morphological fusion of lateral muscles. This study aimed to provide evidence for the inferior part of the lateral myofascial chain. METHODS: Fourteen legs (7 embalmed cadavers, four ♂, 86 ± 7 years) were dissected to reveal a potential myofascial continuity between the fibularis longus muscle, more detailed, its fascia, and the iliotibial tract (ITT). Three investigators judged the general existence as well as the degree and characteristics of the continuity. If an anatomical continuity was evident, strain was applied to both structures in order to evaluate the tissues' ability for tensile transmission. RESULTS: An indirect connection between the iliotibial tract and the fascia of the fibularis longus muscle was found: in all examined legs, the ITT fused strongly with the crural fascia. The latter was hardly separable from the fibularis longus fascia. Application of strain to the ITT caused local movement in the crural fascia and the underlying fascia of the fibularis muscle. CONCLUSIONS: The iliotibial tract fuses firmly with the crural fascia and the degree of continuity suggests that moderate amounts of strain might be transmitted. However, biomechanical studies precisely quantifying this tensile transmission are warranted in order to estimate the relevance of the linkage for the locomotor system.

The human iliotibial band is specialized for elastic energy storage compared with the chimp fascia lata.

This study examines whether the human iliotibial band (ITB) is specialized for elastic energy storage relative to the chimpanzee fascia lata (FL). To quantify the energy storage potential of these structures, we created computer models of human and chimpanzee lower limbs based on detailed anatomical dissections. We characterized the geometry and force-length properties of the FL, tensor fascia lata (TFL) and gluteus maximus (GMax) in four chimpanzee cadavers based on measurements of muscle architecture and moment arms about the hip and knee. We used the chimp model to estimate the forces and corresponding strains in the chimp FL during bipedal walking, and compared these data with analogous estimates from a model of the human ITB, accounting for differences in body mass and lower extremity posture. We estimate that the human ITB stores 15- to 20-times more elastic energy per unit body mass and stride than the chimp FL during bipedal walking. Because chimps walk with persistent hip flexion, the TFL and portions of GMax that insert on the FL undergo smaller excursions (origin to insertion) than muscles that insert on the human ITB. Also, because a smaller fraction of GMax inserts on the chimp FL than on the human ITB, and thus its mass-normalized physiological cross-sectional area is about three times less in chimps, the chimp FL probably transmits smaller muscle forces. These data provide new evidence that the human ITB is anatomically derived compared with the chimp FL and potentially contributes to locomotor economy during bipedal locomotion.

The anatomical and functional relation between gluteus maximus and fascia lata.

There is not full agreement regarding the distal insertions of the gluteus maximus muscle (GM), particularly the insertions into the iliotibial band and lateral intermuscular septum. 6 cadavers, 4 males and 2 females, mean age 69 yr, were dissected to evaluate the insertions of the GM into the iliotibial band, fascia lata, lateral intermuscular septum and femur. The iliotibial band is a reinforcement of the fascia lata and cannot be separated from it. Its inner side is in continuity with the lateral intermuscular septum, which divides the quadriceps from the hamstring. In all subjects the gluteus maximus presented a major insertion into the fascia lata, so large that the iliotibial tract could be considered a tendon of insertion of the gluteus maximus. The fascial insertion of the gluteus maximus muscle could explain the transmission of the forces from the thoracolumbar fascia to the knee.

Combined spectrophotometry and tensile measurements of human connective tissues: potentials and limitations.

Strain-dependent transmission data of nine iliotibial tract specimens are determined using a custom-built optical setup with a halogen light source and an industrial norm material testing machine. Polarized light microscopy and hematoxylin-eosin staining indicated that lateral contraction of collagen structures is responsible for total intensity variations during a 20-cycle preconditioning and a 5-cycle tensile test. Tensile force progress is opposite to total transmission progress. Due to dehydration, wavelength-specific radiation intensity shifting is determined during the test, primarily noticeable in a water absorption band between 1400 and 1500 nm. The results show the capability of integrating spectrophotometry technology into biomechanics for determining structural alterations of human collagen due to applied strain. Being more sensitive to drying, spectrophotometry may likely serve as a quality control in stress-strain testing of biological structures.

Ultimate stress and age-dependent deformation characteristics of the iliotibial tract.

BACKGROUND AND AIMS: To understand biomechanics of ligaments and tendons data on their material properties are necessary. The iliotibial tract is a suitable model for virtual pelvic or lower extremity ligaments due to its parallel fibers, which facilitates biomechanical testing. Here, we determined Young's modulus (YM) as secant stiffness between defined limits of the iliotibial tract and correlated the data to ultimate stress (US) of the specimens and to age, gender and body weight of the body donors. MATERIALS AND METHODS: Thirty eight specimens from 12 iliotibial tracts of 10 young donors (mean age 31.2±9.1 years) were investigated biomechanically. After preconditioning, YM were determined in the ranges of 0-4 and 4-11 N/mm² of applied stress and from 4N/mm² of applied stress to US. RESULTS: YM of the specimens were 84.7±30.2 (0-4 N/mm²), 335.4±101.9 (4-11 N/mm²), and 369.1±191.5 (4 N/mm² to US) N/mm², respectively. The mean US was 35.8±16.4 N/mm². YM and US correlated closely in the ranges of 4-11 N/mm² (r=0.95) and 4 N/mm² to US (r=0.91). YM did not correlate to age, body weight or gender within these young donors. Concerning tissue behavior a decrease of YM, i.e. weakening, is more common than an increase of YM, i.e. stiffening, before specimen failure. Overall, YM of specimens from young donors were significantly lower compared to those of old donors. DISCUSSION AND CONCLUSIONS: This is the first study providing age-dependent nonlinear stiffness properties of the iliotibial tract. YM is significantly lower in young than in old donors and is thus a subject of alteration during life time.

Histomorphological changes of Tutoplast-processed fascia lata grafts in a rabbit rhinoplasty model.

OBJECTIVES: Tutoplast-processed fascia lata (TPFL) is a commercially available homograft that has been successfully used as graft tissue for rhinoplasty. The present study evaluates the histomorphological changes of TPFL in a rabbit rhinoplasty model. STUDY DESIGN: Prospective study using a rabbit model. SETTING: Animal laboratory of the Asan Medical Center. SUBJECTS AND METHODS: The study used 15 New Zealand White rabbits. Each rabbit was implanted with a TPFL (experimental group) and autologous fascia lata (control group) graft of equal size into the nasal dorsum. Rabbits were killed at 1, 3, and 6 months, and the grafts were removed and microscopically assessed for fibroblast proliferation, neovascularization, inflammation, and thickness. RESULTS: For TPFL grafts, the degree of inflammation significantly decreased between 1 and 3 months (P = .041). The degree of fibroblast proliferation continually increased over time. There was a mild degree of neovascularization for the TPFL graft at 1 month. The degree of neovascularization increased between 3 and 6 months (P = .041). For the degree of inflammation, fibroblast proliferation, and neovascularization, there was no significant difference between TPFL and autologous fascia lata at 6 months. Mean thickness analysis showed that there was no significant thickness reduction in both TPFL and autologous fascia lata grafts at 6 months. CONCLUSION: The TPFL grafts showed negligible resorption rates and favorable tissue reactions in the rabbit rhinoplasty model.