Novel Clinical Anatomical Consideration of the Superficial and Deep Layers of the Deep Temporal Fascia.

BACKGROUND: The deep temporal fascia provides anchoring during thread lifting, which is a minimally invasive face-lifting procedure. However, anatomical studies involving the deep temporal fascia in addition to effective and safe thread-lifting procedures are scarce. The authors clarified the anatomy of the superficial layer of the deep temporal fascia and its surrounding structure using ultrasonography, histologic sections, and cadaveric dissection to propose an effective thread-lifting procedure guideline. METHODS: The authors included 20 healthy young participants from the Republic of Korea. Real-time, two-dimensional, B-mode ultrasonography was performed. Longitudinal scanning was performed along three vertical lines: the line passing through the jugale, the anterior margin of the condylar process of the mandible, and the midpoint between the jugale and anterior margin of the condylar process. Histologic samples from three fresh adult cadavers were harvested from 2.5 cm above and below the zygomatic arch. Eighteen fresh adult hemifaces of cadavers from the Republic of Korea (six men and three women, aged 67.3 ± 7.2 years) were used to confirm the morphology of the deep temporal fascia. RESULTS: The superficial layer of the deep temporal fascia crossed the zygomatic arch and was connected to the origin of the zygomaticus major muscle at the line passing through the jugale. The superficial layer continued inferiorly to the parotidomasseteric fascia at the line passing through the midpoint and condylar process of the mandible. CONCLUSION: This study yielded the novel anatomy of the superficial layer of the deep temporal fascia, and this anatomical structure may be used for an ideal thread-lifting procedure.

Anatomical investigation of the pelvic urogenital fascia in 10 formalin-fixed female cadavers: novel insights into the laparoscopic total mesometrial resection.

PURPOSE: Previous anatomical studies of the urogenital fascia (UGF) have focused on males, and there is a lack of relevant anatomical studies on the distribution of the extraperitoneal UGF in females. METHODS: In this investigation, guided by the embryonic development of the female urogenital system, the ventral pelvic fascia structure of 10 female cadavers was dissected, and the distribution and morphology of female extraperitoneal UGF were observed, recorded in text, photographs and video, and 3D modeling was performed. RESULTS: We find that in the female extraperitoneal space there is a migratory fascial structure, the UGF, which surrounds the urogenital system and extends from the perinephric region to the pelvis along with the development of the urogenital organs. The two layers of the UGF are composed of loose connective tissue rich in fat that surrounds the urogenital organs, their accessory vascular structures, and the nerves of the abdominopelvic cavity. In the pelvis, it participates in the formation of the ligamentous structures around the rectum and uterus. Finally, it surrounds the bladder and gradually moves into the loose connective tissue of the medial umbilical fold. CONCLUSIONS: Sorting out the distribution characteristics of UGF has some reference value for studying the metastasis of gynecological tumors, the biomechanical structure of the female pelvis, and the surgical methods of gynecology, colorectal surgery, and hernia surgery.

[Chinese expert consensus on definition and terminology of colon and rectum: mesentery, fascia, and space (2023 edition)].

Anatomy is the foundation of surgery. However, traditional anatomical concepts based on autopsy are no longer sufficient to guide the development of modern surgery. With the advancement of histology and embryology and application of high-resolution laparoscopic technology, surgical anatomy has gradually developed. Meanwhile, some important concepts and terms used to guide surgery have emerged, including: mesentery, fascia, and space. The confusing, controversial, and even inaccurate definitions and anatomical terms related to colorectal surgery seriously affect academic communication and the training of young surgeons. Therefore, the Chinese Society of Colorectal Surgeons, the Chinese Society of Colorectal Surgery, National Health Commission Capacity Building and Continuing Education Center, and China Sexology Association of Colorectal Functional Surgery organized colorectal surgeons to make consensus on the definition and terminology of mesentery, fascia, and space related to colon and rectum, to promote surgeons' understanding of modern anatomy related to colorectal surgery and promote academic communication.

[A decade's review for membrane anatomy: the setting,events in it, order formed by primary fascia and serous membrane].

The successful report of total mesorectal excision (TME)/complete mesocolic excision (CME) has encouraged people to apply this concept beyond colorectal surgery. However, the negative results of the JCOG1001 trial denied the effect of complete resection of the "mesogastrium" including the greater omentum on the oncological survival of gastric cancer patients. People even believe that the mesentery is unique in the intestine, because they have a vague understanding of the structure of the mesentery. The discovery of proximal segment of the dorsal mesogastrium (PSDM) proved that the greater omentum is not the mesogastrium, and further revised the structure (definition) of the mesentery and revealed its container characteristics, i.e. the mesentery is an envelope-like structure, which is formed by the primary fascia (and serosa) that enclose the tissue/organ/system and its feeding structures, leading to and suspended on the posterior wall of the body. Breakdown of this structure leads to the simultaneous reduction of surgical and oncological effects of surgery. People quickly realized the universality of this structure and causality which cannot be matched by the existing theories of organ anatomy and vascular anatomy, so a new theory and surgical map- membrane anatomy began to form, which led to radical surgery upgraded from histological en bloc resection to anatomic en bloc resection.

[Application of membrane anatomy in hepatopancreatobiliary and splenic surgery].

Understanding of a variety of membranous structures throughout the body,such as the fascia,the serous membrane,is of great importance to surgeons. This is especially valuable in abdominal surgery. With the rise of membrane theory in recent years,membrane anatomy has been widely recognized in the treatment of abdominal tumors,especially of gastrointestinal tumors. In clinical practice. The appropriate choice of intramembranous or extramembranous anatomy is appropriate to achieve precision surgery. Based on the current research results,this article described the application of membrane anatomy in the field of hepatobiliary surgery,pancreatic surgery,and splenic surgery,with the aim of blazed the path from modest beginnings.

The characteristics of the urogenital fascia in the retrorectal space based on male cadaveric dissection and its clinical application.

BACKGROUND: The architecture of retrorectal fasciae is complex, as determined by different anatomical concepts. The aim of this study was to examine the anatomical characteristics of the inferomedial extension of the urogenital fascia (UGF) involving the pelvis to explore its relationship with the adjacent fasciae. Furthermore, we have expounded on the clinical application of UGF. METHOD: For our study, we examined 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. Our department has performed 466 laparoscopic rectal cancer procedures since January 2020. We reviewed the surgical videos involving UGF preservation and analyzed the anatomy of the UGF. RESULTS: The bilateral hypogastric nerves ran between the visceral and parietal layers of the UGF. The visceral fascia migrated ventrally at the fourth sacral vertebra, which formed the rectosacral fascia together with the fascia propria of the rectum; the parietal layer continually extended to the pelvic diaphragm, terminating at the levator ani muscle. At the third to fourth sacral vertebra level, the two layers constituted the lateral ligaments. CONCLUSION: The double layers of the UGF are vital structures for comprehending the posterior fascia relationship of the rectum. The upper segment between the fascia propria of the rectum and the visceral layer has no evident nerves or blood vessels and is regarded as the " holy plane" for the operation.

Reappraisal of the anatomy of the frontotemporal branches of the facial nerve.

OBJECTIVE: The anatomy of the temporal branches of the facial nerve (FN) has been widely described in the neurosurgical literature because of its relevance in anterolateral approaches to the skull base and implication in frontalis palsies from these approaches. In this study, the authors attempted to describe the anatomy of the temporal branches of the FN and identify whether there are any FN branches that cross the interfascial space of the superficial and deep leaflets of the temporalis fascia. METHODS: The surgical anatomy of the temporal branches of the FN was studied bilaterally in 5 embalmed heads (n = 10 extracranial FNs). Exquisite dissections were performed to preserve the relationships of the branches of the FN and their relationship to the surrounding fascia of the temporalis muscle, the interfascial fat pad, the surrounding nerve branches, and their final terminal endpoints near the frontalis and temporalis muscles. The authors correlated their findings intraoperatively with 6 consecutive patients with interfascial dissection in which neuromonitoring was performed to stimulate the FN and associated twigs that were observed to be interfascial in 2 of them. RESULTS: The temporal branches of the FN stay predominantly superficial to the superficial leaflet of the temporal fascia in the loose areolar tissue near the superficial fat pad. As they course over the frontotemporal region, they give off a twig that anastomoses with the zygomaticotemporal branch of the trigeminal nerve, which crosses the superficial layer of the temporalis muscle, spanning the interfascial fat pad, and then pierces the deep temporalis fascial layer. This anatomy was observed in 10 of the 10 FNs dissected. Intraoperatively, stimulation of this interfascial segment yielded no facial muscle response up to 1 mA in any of the patients. CONCLUSIONS: The temporal branch of the FN gives off a twig that anastomoses with the zygomaticotemporal nerve, which crosses the superficial and deep leaflets of the temporal fascia. Interfascial surgical techniques aimed at protecting the frontalis branch of the FN are safe in their efforts to protect against frontalis palsy with no clinical sequelae when executed properly.

The Anatomy Study of Temporal Region based on Ultrasound Investigation: A Spatial Structure Study.

BACKGROUND: With the growing popularity of rejuvenation, people are giving more concerns on their temporal depression which makes them look older and wishing to improve it by injection. The complex structure of the temporal region leads to a higher risk of failed injection. The temporal region is well understood based on cadaver anatomy, but few studies have described its spatial structure. The purpose of this study was to improve the efficacy and safety of temporal injection by studying the spatial structure of the soft tissues and major blood vessels in each layer of the temporal region. METHODS: A total of 30 volunteers (24 men and 6 women, 60 temporal regions) were investigated. Color Doppler ultrasound was used to measure the thickness of the temporal layers at the selected measurement points (A, B, C, D, E, and F). The maximum thickness of the temporal fat pads was also measured, and the layers, depths and diameters of the major temporal vessels (frontal branch of superficial temporal artery and vein, middle temporal vein and deep temporal artery) were measured. RESULTS: At the various measurement points, the thickness and position of the skin, subcutaneous fat superficial fascia, and temporalis muscle did not differ significantly, whereas the superficial temporal fat pad and deep temporal fat pad differed significantly. The diameter and depth of the superficial temporal artery, superficial temporal vein, and deep temporal artery did not differ significantly, whereas the diameter of the middle temporal vein differed slightly, whereas the depth differed more obviously. CONCLUSIONS: The temporal structure is very complex, and understanding the spatial position of each layer of tissue plays an important role in improving the efficacy and safety of temporal filler injection. Ultrasound can help us to understand this information and assist in therapy. LEVEL OF EVIDENCE: Level II.

Acute Effects of Percussive Massage Therapy on Thoracolumbar Fascia Thickness and Ultrasound Echo Intensity in Healthy Male Individuals: A Randomized Controlled Trial.

Percussive massage therapy (PT) has been widely used by therapists and the fitness population to treat myofascial-related conditions. However, there is no evidence to confirm the effects of PT on the fascia. This study aimed to investigate the effects of PT on thoracolumbar fascia (TLF) morphology and other related outcomes. METHODS: Sixty-six healthy males participated and were randomly allocated into a percussive massage group (PT group) and a control group. The PT group received 15 min of back percussion massage, while the control group rested prone lying in the same environment for 15 min. Thoracolumbar fascia (TLF) thickness and echo intensity, perceived stiffness, lumbar flexibility, and skin temperature were measured in both groups before and immediately after the intervention. RESULT: TLF thickness and lumbar flexibility did not change when compared in the two groups. However, the echo intensity (left side, difference -3.36, 95% CI -5.1 to -1.6; right side, difference -4.39, 95% CI -6.1 to -2.7) and perceived stiffness (difference, -1.18, 95% CI -1.84 to -0.52) in the TLF region were significantly lower in the PT group than in the control group and were accompanied by increased skin temperature (difference 0.29, 95% CI 0.11 to 0.48). CONCLUSION: We suggest that a 15 min PT with 30 Hz on the back region could reduce TLF echo intensity and perceived stiffness and increase skin temperature in healthy men individual.

Enhanced study of facial soft tissues using a novel large scale histology technique.

The safety and effectiveness of facial cosmetic surgery procedures are dependent on detailed 3D understanding of the complex surgical anatomy of the face. Traditional, small sample size anatomical dissection studies have limitations in providing definitive clarification of the fascial layers of the face, and especially in their relationship with the facial nerve, and their reaction to surgical manipulation. The objective study of large tissue areas is required to effectively demonstrate the broader architecture. Conventional histology techniques were modified to handle extraordinarily large tissue samples to fulfill this requirement. Full-thickness soft tissue samples (skin to bone) of maximum length 18 cm, width 4 cm, and tissue thickness 1 cm, were harvested from 20 hemifaces of 15 fresh human cadavers (mean age at death = 81 years). After fixation, the samples were processed with an automated processor using paraffin wax for 156 h, sectioned at 30 µm, collected on gelatin-chromium-coated glass slides, stained with a Masson's Trichrome technique and photographed. Using this technique, excellent visualization was obtained of the fascial connective tissue and its relationship with the facial mimetic muscles, muscles of mastication and salivary glands in 73 large histological slides. The resulting slides improved the study of the platysma and superficial musculo-aponeurotic system (SMAS), the spaces and ligaments, the malar fat pad, and the facial nerve in relations to the deep fascia. Additionally, surgically induced changes in the soft-tissue organization were successfully visualized. This technique enables improved insight into the broad structural architecture and histomorphology of large-scale facial tissues.

New anatomical insights of the superficial branch of the zygomaticotemporal nerve for treating temporal migraines: An anatomical study.

The zygomaticotemporal nerve is known to contribute to temporal migraines; however, its precise anatomy remains unknown. The potential accessory branches of the zygomaticotemporal nerve may be considered a cause of continued temporal migraines after surgical procedures. In this study, we defined the novel superficial branch of the zygomaticotemporal nerve (sZTN) and investigated its anatomical course, distribution, and clinical implications. Twenty-two hemifaces from 11 fixed Korean cadavers (six males, five females; mean age, 78.3 years) were used in this study. The piercing points of the sZTN through the deep and superficial layers of the deep temporal fascia, and the superficial temporal fascia were defined as P1, P2, and P3, respectively. The distance of each point from the zygomatic tubercle was measured using an image analysis software. The sZTN ascended between the bone and the temporalis after emerging from the zygomaticotemporal foramen. It then pierced the deep temporal fascia without penetrating the temporalis. After then, it pierced the superficial layer of the deep temporal fascia and turned superiorly toward the upper posterior temple. When the sZTN passed through the superficial temporal fascia, it intersected with the superficial temporal artery in every case. The novel findings of the sZTN may help in the treatment of intractable temporal migraines refractory to injection or surgical procedure. Based on our findings, targeting the sZTN may be applied as an alternative treatment strategy for patients who do not show significant improvement with treatment targeted to trigger sites.

The Superficial Fascia System: Anatomical Guideline for Zoning in Liposuction-Assisted Back Contouring.

BACKGROUND: Dorsal contour deformity presents with different manifestations in each part of the back, such as back rolls, iliac crest deposit, and buffalo hump. However, scant current literature exists on the anatomical basis of dorsal contour deformity. The aim of this study was to better understand the anatomical characteristics of the back, and to propose evidence-based zoning principles for liposuction-assisted back contouring. METHODS: A total of 12 fresh cadavers were dissected for observation of each hierarchy in the vertical order (skin to deep fascia) and transverse comparison of the superficial fascial system (SFS) in the scapular-infrascapular-lumbar triangle region. Full-dorsum vectorial sections were used for the study of suprascapular fat deposits. RESULTS: The SFS acts as a bridge connecting all levels of the dorsal subcutaneous tissue. Macroscopically, it is denser in the scapular and lumbar triangle regions and looser in the infrascapular region; microscopically, the ultrastructure of the retinaculum cutis consists of loose interlobular fascia and stiff functional fascia. CONCLUSIONS: The regional variation pattern of the SFS in the back was consistent with observed back contour deformities in Asian female patients. A better understanding of the topographic anatomy of the back applied to evidenced zoning is the basis for improving surgical precision and avoiding dorsal contour deformity.

A decade's review for membrane anatomy: the setting,events in it, order formed by primary fascia and serous membrane / 中华胃肠外科杂志

The successful report of total mesorectal excision (TME)/complete mesocolic excision (CME) has encouraged people to apply this concept beyond colorectal surgery. However, the negative results of the JCOG1001 trial denied the effect of complete resection of the "mesogastrium" including the greater omentum on the oncological survival of gastric cancer patients. People even believe that the mesentery is unique in the intestine, because they have a vague understanding of the structure of the mesentery. The discovery of proximal segment of the dorsal mesogastrium (PSDM) proved that the greater omentum is not the mesogastrium, and further revised the structure (definition) of the mesentery and revealed its container characteristics, i.e. the mesentery is an envelope-like structure, which is formed by the primary fascia (and serosa) that enclose the tissue/organ/system and its feeding structures, leading to and suspended on the posterior wall of the body. Breakdown of this structure leads to the simultaneous reduction of surgical and oncological effects of surgery. People quickly realized the universality of this structure and causality which cannot be matched by the existing theories of organ anatomy and vascular anatomy, so a new theory and surgical map- membrane anatomy began to form, which led to radical surgery upgraded from histological en bloc resection to anatomic en bloc resection.

Application of membrane anatomy in hepatopancreatobiliary and splenic surgery / 中华外科杂志

Understanding of a variety of membranous structures throughout the body,such as the fascia,the serous membrane,is of great importance to surgeons. This is especially valuable in abdominal surgery. With the rise of membrane theory in recent years,membrane anatomy has been widely recognized in the treatment of abdominal tumors,especially of gastrointestinal tumors. In clinical practice. The appropriate choice of intramembranous or extramembranous anatomy is appropriate to achieve precision surgery. Based on the current research results,this article described the application of membrane anatomy in the field of hepatobiliary surgery,pancreatic surgery,and splenic surgery,with the aim of blazed the path from modest beginnings.

Chinese expert consensus on definition and terminology of colon and rectum: mesentery, fascia, and space (2023 edition) / 中华胃肠外科杂志

Anatomy is the foundation of surgery. However, traditional anatomical concepts based on autopsy are no longer sufficient to guide the development of modern surgery. With the advancement of histology and embryology and application of high-resolution laparoscopic technology, surgical anatomy has gradually developed. Meanwhile, some important concepts and terms used to guide surgery have emerged, including: mesentery, fascia, and space. The confusing, controversial, and even inaccurate definitions and anatomical terms related to colorectal surgery seriously affect academic communication and the training of young surgeons. Therefore, the Chinese Society of Colorectal Surgeons, the Chinese Society of Colorectal Surgery, National Health Commission Capacity Building and Continuing Education Center, and China Sexology Association of Colorectal Functional Surgery organized colorectal surgeons to make consensus on the definition and terminology of mesentery, fascia, and space related to colon and rectum, to promote surgeons' understanding of modern anatomy related to colorectal surgery and promote academic communication.

Embryonic developmental process and clinical anatomy of the preperitoneal fascia and its clinical significance.

PURPOSE: Many researchers have different views on the origin and anatomy of the preperitoneal fascia. The purpose of this study is to review studies on the anatomy related to the preperitoneal fascia and to investigate the origin, structure, and clinical significance of the preperitoneal fascia in conjunction with previous anatomical findings of the genitourinary fascia, using the embryogenesis of the genitourinary system as a guide. METHODS: Publications on the preperitoneal and genitourinary fascia are reviewed, with emphasis on the anatomy of the preperitoneal fascia and its relationship to the embryonic development of the genitourinary organs. We also describe previous anatomical studies of the genitourinary fascia in the inguinal region through the fixation of formalin-fixed cadavers. RESULTS: Published literature on the origin, structure, and distribution of the preperitoneal fascia is sometimes inconsistent. However, studies on the urogenital fascia provide more than sufficient evidence that the formation of the preperitoneal fascia is closely related to the embryonic development of the urogenital fascia and its tegument. Combined with previous anatomical studies of the genitourinary fascia in the inguinal region of formalin-fixed cadavers showed that there is a complete fascial system. This fascial system moves from the retroperitoneum to the anterior peritoneum as the preperitoneal fascia. CONCLUSIONS: We can assume that the preperitoneal fascia (PPF) is continuous with the retroperitoneal renal fascia, ureter and its accessory vessels, lymphatic vessels, peritoneum of the bladder, internal spermatic fascia, and other peritoneal and pelvic urogenital organ surfaces, which means that the urogenital fascia (UGF) is a complete fascial system, which migrates into PPF in the preperitoneal space and the internal spermatic fascia in the inguinal canal.

The Deep Fascia of the Infraorbital Region, Deep Plane, and Suprafibromuscular Facelift: New Anatomy for Safer Facelifting.

Deep-plane rhytidectomy, first described by Skoog, has had a resurgence in popularity and is in high demand today. We describe anatomical findings that establish the presence of a true deep fascia in the midface, we named as Chiara's fascia, like the first author's first name, which helps to form the facial ligaments and is contiguous with the superficial layer of the deep temporal fascia. This fascia inserts on the periosteum of the inferior orbital rim at the arcus marginalis and separates the suborbicularis oculi fat (SOOF) from the preperiosteal fat. This distinct fascial layer lies under the superficial fascia or superficial musculoaponeurotic system (SMAS) and represents the floor of what is commonly termed the "deep plane." When this fascial highway is identified intraoperatively, blunt dissection immediately superficial to this layer will protect facial nerve branches overlying the muscles lifting the upper lip such as the zygomaticus. Subsequent dissection over the middle and lower face can usually be performed bluntly. Over a 10-year period, a total of 100 hemifaces were dissected with a 100% success rate of identifying this fascia in all specimens. This work was further validated by examining histologic specimens that clearly demonstrate this unique fibrofatty fascial layer. These dissections and new anatomical findings were then correlated to over 300 intraoperative deep-plane facelift cases by the primary and senior authors. We term this operative technique as the suprafibromuscular facelift. Dissection in this plane allows for safe release of facial retaining ligaments with protection of facial nerve branches.

Macroscopic Anatomy of the Layered Structures of Facial Muscles and Fasciae in the Temporal-Malar-Mandible-Neck Region.

The layered structures of facial muscles and their topographical relationship with facial fasciae are still not fully understood. This study aimed to clarify the layered structures of facial muscles and fasciae in the temporal-malar-mandible-neck region. Thirty-four human cadavers were examined during gross anatomy courses at Niigata University (2017-2020). The face was composed of 3-layered (deep, middle, and superficial) fasciae and 4-layered facial muscles (first superficial, second superficial, third, and fourth muscle layers) according to the attachment of muscles and their topographical relationship with the fasciae. The deep fascia covered the temporal and masseter muscles. The parotid gland and facial nerves were enveloped in the middle fascia. The superficial fascia was continuous with the second superficial muscle layer. The connection between fourth and superficial muscles was at the malar and buccal areas, where the platysma blended with the masseter and the plural muscles blended with the buccinator. Our findings suggest that cooperation between the 4-layered structure of the facial muscles surrounding the apertures of the eyes and mouth and the superficial fascia enables humans to produce complex facial expressions. Furthermore, the spread of inflammation in the face may be owing to the layered facial muscles and fasciae, as these layered structures separate tissues into multiple compartments.

In Vivo Analysis of the Superficial and Deep Fascia.

BACKGROUND: Key risk factors for hypertrophic scarring and surgical-site infections are high-tension wounds, fat necrosis, and dead space. All could be prevented by appropriate superficial fascia suturing. However, the as-yet poorly researched anatomy of the superficial fascia should be delineated. This study is the first to quantify the superficial fascia throughout the human body in vivo. METHODS: Ultrasound was used to analyze the superficial and deep fascia of 10 volunteers at 73 points on 11 body regions, including the upper and lower trunk and limbs. Number, thickness and percentage of superficial fascia layers, and deep fascia and dermis thickness, were measured at each point. RESULTS: Seven hundred thirty ultrasound images were analyzed. Body regions varied markedly in terms of subcutaneous variables. Posterior chest had the thickest deep fascia and dermis and the highest average superficial fascia layer thickness [0.6 mm (95 percent CI, 0.6 to 0.7 mm)]. Anterior chest had the most superficial fascia layers [3.7 (95 percent CI, 3.5 to 3.8)]. Posterior and anterior chest had among the highest percentage of superficial fascia. Abdomen and especially gluteus had a low percentage of superficial fascia. Covariate analyses confirmed that posterior and anterior chest generally had higher superficial fascia content than gluteus and abdomen (both p < 0.001). They also showed that the dermis in the posterior and anterior chest increased proportionally to total fascia thickness. CONCLUSIONS: The superficial fascia, deep fascia, and dermis tend to be thick in high-tension areas such as the upper trunk. A site-specific surgical approach is recommended for subcutaneous sutures. CLINICAL RELEVANCE STATEMENT: Understanding the anatomical distribution of the superficial fascia and deep fascia will help surgeons optimize subcutaneous fasciae suturing, thereby potentially reducing the incidence of surgical-site infections and hypertrophic scars.

Distribution of various volumes of methylene blue injection in suprainguinal fascia iliaca block under ultrasound guidance: a cadaveric study / Distribución de varios volúmenes de inyección de azul de metileno en el bloque suprainguinal de la fascia ilíaca bajo guía por ultrasonido: un estudio cadavérico

SUMMARY: The local anesthetic volume for a single-shot suprainguinal fascia iliaca block (SFIB) is a key factor of a block success because the courses of the three target nerves from the lumbar plexus (LP), the lateral femoral cutaneous nerve (LFCN), femoral nerve (FN), and obturator nerve (ON), at the inguinal area are isolated and within striking distance. Thus, this cadaveric study aims to demonstrate the distribution of dye staining on the LFCN, FN, ON, and LP following the ultrasound-guided SFIB using 15-50 ml of methylene blue. A total of 40 USG-SFIBs were performed on 20 fresh adult cadavers using 15, 20, 25, 30, 35, 40, 45, and 50 ml of methylene blue. After the injections, the pelvic and inguinal regions were dissected to directly visualize the dye stained on the LFCN, FN, ON, and LP. All FN and LFCN were stained heavily when the 15-50 ml of dye was injected. Higher volumes of dye (40-50 ml) spread more medially and stained on the ON and LP in 60 % of cases. To increase the possibility of dye spreading to all three target nerves and LP of the SFIB, a high volume (≥40 ml) of anesthetic is recommended. If only a blockade of the FN and LFCN is required, a low volume (15-25 ml) of anesthetic is sufficient.

RESUMEN: El volumen de anestésico local para un bloqueo de la fascia ilíaca suprainguinal (FISI) de una sola inyección es un factor clave para el éxito del bloqueo, debido a que los cursos de los tres nervios objetivo del plexo lumbar (PL), el nervio cutáneo femoral lateral (NCFL), femoral (NF) y el nervio obturador (NO), en el área inguinal están aislados y dentro de la distancia de abordaje. Por lo tanto, este estudio cadavérico tiene como objetivo demostrar la distribución de la tinción de tinte en NCFL, NF, NO y PL siguiendo el FISI guiado por ultrasonido usando 15-50 ml de azul de metileno. Se realizaron un total de 40 USG-FISI en 20 cadáveres adultos frescos utilizando 15, 20, 25, 30, 35, 40, 45 y 50 ml de azul de metileno. Después de las inyecciones, se disecaron las regiones pélvica e inguinal para visualizar directamente el tinte teñido en NCFL, NF, NO y PL. Todos los NF y NCFL se tiñeron intensamente cuando se inyectaron los 15- 50 ml de colorante. Volúmenes mayores de colorante (40-50 ml) se esparcen más medialmente y tiñen el NO y la PL en el 60 % de los casos. Para aumentar la posibilidad de que el colorante se propague a los tres nervios objetivo y al PL del FISI, se recomienda un volumen elevado (≥40 ml) de anestésico. Si solo se requiere un bloqueo de NF y NCFL, un volumen bajo (15-25 ml) de anestésico es suficiente.