Correlation between preoperative CT scan of the paraspinal, psoas, and gluteus muscles and postoperative ambulatory status in patients with femoral neck fractures.

BACKGROUND: This study aimed to investigate the relationship between femoral neck fractures and sarcopenia. METHODS: This was a retrospective analysis of 92 patients with femoral neck fractures, from September 2017 to March 2020, who were classified into high ambulatory status (HG) and low ambulatory status (LG) groups. Ambulatory status was assessed before surgery, one week after surgery, at discharge, and during the final follow-up. To evaluate sarcopenia, muscle mass and fatty degeneration of the muscles were measured using preoperative CT. An axial slice of the superior end of the L5 vertebra was used to evaluate the paraspinal and psoas muscles, a slice of the superior end of the femoral head for the gluteus maximus muscle, and a slice of the inferior end of the sacroiliac joint for the gluteus medius muscle. The degeneration of the muscles was evaluated according to the Goutallier classification. RESULTS: The cross-sectional area of the gluteus medius and paraspinal muscles was significantly correlated with ambulatory status before the injury, at discharge, and during the final follow-up. CONCLUSIONS: Measurement of the gluteus medius and paraspinal muscles has the potential to evaluate sarcopenia and predict ambulatory status after femoral neck fractures.

Danger Zones of the Gluteal Anatomy: Improving the Safety Profile of the Gluteal Fat Grafting.

INTRODUCTION: Knowledge of the vascular anatomy is critical to performing safe gluteal surgery. To date, only the course of the main blood vessels within the muscles has been outlined. These findings are based on MRI and CTA images that do not conform to a topographically standardized and normalized probability distribution. OBJECTIVES: The aim of this study was to develop a three-dimensional mapping of the gluteal zones of high vascular density in relation to anatomical landmarks. MATERIALS AND METHODS: This single-center retrospective cohort analysis comprised all consecutive patients who underwent cone-beam computed tomography (CBCT) scans between January 2016 and October 2021. The location of blood vessels in the gluteal region was allometrically normalized in relation to anatomical landmarks. Moreover, the caliber and area of the blood vessels were assessed. RESULTS: CBCT scans of 32 patients with an average age of 64 ± 12 years (range 34-87 years) were included. Fifty-three percent were female. The median [IQR] caliber of the intramuscular gluteal vessels was 1.47 [1.15-1.88] mm, significantly greater than that of the subcutaneous vessels 1.09 [0.72-1.44] mm (p < 0.001). Vascular density was higher intramuscularly, as 4.5% of the area of the muscle was occupied by blood vessels, as opposed to 0.3% in the adipose tissue. CONCLUSION: The analysis of the CBCT scans showed a higher vascular density and larger vessels intramuscularly. We, therefore, recommend the injection of autologous fat merely to the subcutaneous plane. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The inferior gluteal artery anatomy: a detailed analysis with implications for plastic and reconstructive surgery.

BACKGROUND: The inferior gluteal artery (IGA) is a large terminal branch of the anterior division of the internal iliac artery (ADIIA). There is a significant lack of data regarding the variable anatomy of the IGA. MATERIALS AND METHODS: A retrospective study was conducted to establish anatomical variations, their prevalence and morphometrical data on IGA and its branches. The results of 75 consecutive patients who underwent pelvic computed tomography angiography were analysed. RESULTS: The origin variation of each IGA was deeply analysed. Four origin variations have been observed. The most common type O1 occurred in 86 of the studied cases (62.3%). The median IGA length was set to be 68.50 mm (lower quartile [LQ]: 54.29; higher quartile [HQ]: 86.06). The median distance from the origin of the ADIIA to the origin of the IGA was set to be 38.22 mm (LQ: 20.22; HQ: 55.97). The median origin diameter of the IGA was established at 4.69 mm (LQ: 4.13; HQ: 5.45). CONCLUSIONS: The present study thoroughly analysed the complete anatomy of the IGA and the branches of the ADIIA. A novel classification system for the origin of the IGA was created, where the most prevalent origin was from the ADIIA (type 1; 62.3%). Furthermore, the morphometric properties (such as the diameter and length) of the branches of the ADIIA were analysed. This data may be incredibly useful for physicians performing operations in the pelvis, such as interventional intraarterial procedures or various gynaecological surgeries.

Cosmetic Injection of Illicit Foreign Materials: Imaging Features and Patterns of Migration in 413 Cases.

BACKGROUND: The injection of illicit, nonregulated foreign materials is increasingly common and has negative consequences relative to the inflammatory process that ensues. OBJECTIVES: The aim of this study was to identify anatomical and imaging characteristics after the cosmetic injection of illicit foreign materials. METHODS: A retrospective review of clinical and imaging records was performed. The issues analyzed were the anatomical site, type of injected substance, imaging method for diagnosis, and patterns of migration. RESULTS: Data on 413 patients were collected. Most patients were female, with a mean age of 44 years. The most commonly infiltrated region was the buttocks (n = 284; 53.58%) followed by the breast (n = 99; 18.67%). Magnetic resonance imaging was the most common method of diagnosis in those patients who had an imaging study (159 out of 168). The most frequent depth of foreign material detected by imaging was the muscular plane (n = 103; 61.30%). Migration was detected in 56.55% of patients who had an imaging study. Most infiltrated substances were unknown; biopolymers were the most commonly identified substances. Depending on the type of substance, migration rates varied from 13% to 29%; rate differences were not statistically significant (P = .712). Migration was more common when the depth of infiltration was in muscle (77.66%) than in subcutaneous tissue (23.4%); this difference was statistically significant (P < .0001). CONCLUSIONS: Deep infiltration is related to greater migration rates, apparently regardless of the substance injected.

Potential of whole-body dual-energy X-ray absorptiometry to predict muscle size of psoas major, gluteus maximus and back muscles.

BACKGROUND: Measurement of trunk muscle cross-sectional area (CSA) using axial magnetic resonance imaging (MRI) is considered clinically meaningful for understanding several spinal pathologies, such as low back pain and spinal sagittal imbalance. However, it remains unclear whether trunk muscle mass (TMM) measured using dual-energy X-ray absorptiometry (DXA) can predict the trunk muscle CSA. The aim of this study is to determine if DXA-derived TMM is associated and predicts with CSA of paraspinal muscles and gluteus maximus measured using MRI in healthy volunteers. METHODS: A total of 48 healthy volunteers underwent whole-body DXA and MRI of the spinopelvic region. The CSA of the psoas major, back muscles, and gluteus maximus were measured on axial MRI. Correlations and linear regressions between the TMM measured using DXA and the CSA of each musculature were investigated. RESULTS: There was a weak correlation between TMM and CSA of the psoas major in men (r = 0.39, P = 0.0678), and the linear regression was y = 301.74x - 401.24 (R2 = 0.2976, P = 0.0070). A moderate correlation was found in women (r = 0.58, P = 0.0021), and the linear regression was y = 230.21x - 695.29 (R2 = 0.4445, P = 0.0003). Moderate correlations were observed between TMM and CSA of the back muscles in both men (r = 0.63, P = 0.0012) and women (r = 0.63, P = 0.0007), the linear regression was y = 468.52x + 3688.5 (R2 = 0.5505, P < 0.0001) in men and y = 477.39x + 2364.1 (R2 = 0.564, P < 0.0001) in women. There was a strong correlation between TMM and CSA of the gluteus maximus in men (r = 0.72, P < 0.0001), and the linear regression was y = 252.69x - 880.5 (R2 = 0.6906, P < 0.0001). A moderate correlation was found in women (r = 0.69, P < 0.0001), and the linear regression was y = 230.74x - 231.32 (R2 = 0.6542, P < 0.0001). CONCLUSIONS: The DXA-derived TMM was able to predict the CSA of the psoas major, back muscles, and gluteus maximus, and significantly correlated with the CSA of the back muscles and gluteus maximus. It might be a safer and cheaper alternative for evaluating the size of the back muscles and gluteus maximus.

Correlation Between Atrophy of the Gluteus Medius Muscle and Symptoms of Lumbar Spinal Stenosis.

OBJECTIVE: Lower muscular weakness and gait disturbance are typical lumbar spinal stenosis (LSS) symptoms. Gait initiation and standing balance function are dependent on hip muscle groups, particularly gluteus medius (GMed). However, alterations to GMed in patients with LSS have not been studied. Therefore, we evaluated the impact of LSS on GMed in this study. METHODS: This study included 96 participants divided into the LSS and non-LSS groups. A total of 48 patients with LSS and unilateral buttock pain underwent T2-weighted magnetic resonance imaging of GMed, and 48 age- and sex-matched controls formed the control group. Differences between the cross-sectional areas (CSAs) on both sides of GMed were compared between the 2 groups. Additionally, correlations among patient characteristics, clinical evaluation, and radiological measurement data with a decrease in the CSA of GMed were assessed in the LSS group. RESULTS: A significant difference was observed in the bilateral discrepancy of the GMed CSA between the LSS and non-LSS groups. For patients with LSS with unilateral buttock pain, 81% had reduced CSA of GMed. Regression analysis revealed that buttock pain was an independent factor related to GMed atrophy. CONCLUSIONS: The degree of GMed atrophy is related to symptoms of LSS. Spine surgeons should be aware of the risk of GMed atrophy in patients with LSS with unilateral buttock pain.

Aggressive gluteal fibromatosis: a rare case associated with spontaneous superior gluteal artery pseudoaneurysm.

Deep fibromatosis is a locally aggressive neoplasm commonly involving the extremities. Several authors have described imaging features and complications associated with deep fibromatosis. We present the case of a 33-year-old man who presented with a right gluteal fibrous mass identified on magnetic resonance imaging (MRI), which was associated with a pseudoaneurysm originating from the right superior gluteal artery on serial follow-up with MRI and computed tomography. No intervention was done, and after conservative management, spontaneous thrombosis of the pseudoaneurysm was developed. Such imaging finding is the first report of a spontaneous development of pseudoaneurysm caused by deep fibromatosis, which could be a life-threatening condition and should be considered when dealing with deep fibromatosis and deciding on the appropriate treatment.

What Makes a Beautiful Buttock Beautiful? A Case-Control Study Comparing Buttocks Models versus Normal Women by Magnetic Resonance Imaging, Photography and Anthropometry.

OBJECTIVES: To describe characteristics of women with aesthetically ideal buttocks and differentiate them from women with normal buttocks. METHODS: Case-control study comparing anatomy of women with ideal buttocks (buttocks models) to women with normal buttocks using magnetic resonance images, anthropometric measurements and photography. RESULTS: Comparing to normal women, buttocks models have a narrower waist, narrower iliac crest, wider C point, wider hips and bigger and thicker gluteus maximus muscle (GMM). A bigger GMM adds more projection to the C point, point of maximum projection in the lateral view is 2.7 cm higher than the pubic bone. The amount of subcutaneous fat was equal in models and controls. CONCLUSIONS: Our study provides new knowledge regarding the tridimensional aspects of the beauty of the buttocks area. A beautiful buttock is a conjunction of adequate bony shape, muscle development, subcutaneous fat layer, and tight skin. Comparing to normal women, buttocks models have a narrower waist, narrower iliac crest, wider C point, wider hips and bigger and thicker Gluteus Maximus Muscle. Accurate understanding of the aesthetic goals in a given patient can guide surgical technique. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparison of Lumbar Artery and Superior Gluteal Artery Perforator Flaps for Breast Reconstruction: Multislice CT-Based Anatomical Study.

BACKGROUND: Although the deep inferior epigastric artery perforator flap is the criterion standard for autologous breast reconstruction, lumbar artery perforator (LAP) and superior gluteal artery perforator (SGAP) flaps are recent trends as alternatives. The purpose of our study was to clarify differences of these flaps based on multislice CT findings of the same patient. METHODS: Retrospective study was conducted on 58 patients who underwent preoperative contrast-enhanced multislice CT for breast reconstruction using deep inferior epigastric artery perforator. Of these, 32 patients' data were evaluated excluding 26 patients' data either for the lumbar or gluteal fat being outside the imaging range or for nondepiction of the vascular pedicle origin of LAP or SGAP flap. Vascular pedicle diameter, pedicle length, and subcutaneous fat thickness were measured for LAP and SGAP flaps. RESULTS: The vascular pedicle diameter, pedicle length, and fat thickness were 2.1 (SD, 0.3) mm, 3.4 (SD, 0.4) cm, and 4.9 (SD, 1.0) cm, respectively, for LAP flaps; and 1.7 (SD, 0.2) mm, 5.6 (SD, 1.1) cm, and 2.7 (SD, 0.7) cm, respectively, for SGAP flaps. CONCLUSIONS: The LAP flaps had thicker subcutaneous fat and a larger vascular pedicle diameter, whereas the SGAP flaps had a longer vascular pedicle. As donor material for breast reconstruction, the LAP flap is indicated for cases where absolute volume is needed; otherwise, the SGAP flap is more advantageous as it facilitates vascular anastomosis with its longer vascular pedicle.

Embolization of Large Internal Iliac Artery Pseudoaneurysm through a Retrograde Trans-Superior Gluteal Arterial Access.

The presence of osteal stenosis/occlusion or osteal exclusion by prior interventions poses a challenge to selective catheterization of the internal iliac artery. We describe a case where a retrograde access through the superior gluteal artery (SGA) was used to successfully treat an internal iliac artery pseudoaneurysm (PSA) in a patient when an antegrade catheterization was not feasible due to internal iliac osteal exclusion by an endograft.

Point of care ultrasound needle guidance to assist diagnosis of acute gluteal compartment syndrome.

Gluteal compartments can be difficult to assess for acute compartment syndrome (ACS) compared to other fascial compartments due to their anatomy and rarity of presentation. Point-of-care ultrasound (POCUS) needle guidance may assist in obtaining accurate compartment pressure measurements within the gluteal compartments. We present a case in which a 69-year-old woman presented following a fall resulting in a superior prosthetic hip dislocation. One-hour post hip-reduction, the patient began to experience severe pain of the right leg, swelling to the gluteal region, and numbness to her foot. With consideration of a developing gluteal compartment syndrome in mind, POCUS was used to guide the needle of a compartmental pressure monitor system into the gluteal maximus and medius-minimus compartments which demonstrated elevated compartment pressures consistent with ACS. The patient was subsequently taken for emergent fasciotomy and hematoma evacuation. There has been limited investigation into compartment pressure measurement under US guidance versus a palpation/landmark-guided technique. This case shows the feasibility of US needle guidance when assessing compartment pressures for this uncommon diagnosis.

Dynamic ultrasound evaluation of body fillers and biostimulators in the buttocks of fresh-frozen specimen.

BACKGROUND: Ultrasound imaging is a useful tool to study the injection of fillers and biostimulators in the body. OBJECTIVE: Sonographically evaluate real-time injections of fillers and biostimulators and describe their behavior in the subcutaneous tissue of the buttocks of fresh-frozen specimen. METHODS: injection of two brands of high-density hyaluronic acid (HA), one brand of calcium hydroxyapatite (CaHA), one brand of hybrid injectable (CaHa + HA), one brand of polycaprolactone (PCL) and three brands of poly-l-lactic acid (PLLA) were performed in the subcutaneous tissue of the gluteal region under ultrasonography visualization on a fresh-frozen specimen. Videos during injection and static images immediately after injection were obtained. The sonographic aspects of the substances and their dispersion and interaction with the surrounding tissues were described. RESULTS: Real-time ultrasound showed different dispersion patterns of the two brands of HA, CaHA, hybrid injectable (CaHa + HA) and the three brands of PLLA. The sonographic aspects among the brands of PLLA were also different. CONCLUSIONS: The dynamic ultrasound evaluation of the injection of HA, CaHA, hybrid injectable (CaHa + HA), PCL and PLLA in a fresh-frozen specimen shed some light on their aspects and dispersion pattern in the buttock. If these patterns are confirmed in further studies in vivo, there will be a positive impact on the selection and development of safer and more effective techniques to enhance buttock contour.

Magnetic resonance imaging study of the sciatic nerve variation in the pediatric gluteal region: Implications for the posterior approach of the sciatic nerve blockade.

INTRODUCTION: In pediatric patients, the sciatic nerve is one of the most commonly blocked peripheral nerves during orthopedic procedures of the lower limb. Ultrasound guidance is the current standard for a successful localization of the sciatic nerve in the gluteal region. Relevant anatomical landmarks are also used to determine the nerve location when ultrasound is not available or inadequate. However, reports have demonstrated paucity of information regarding the sciatic nerve location and variation in the hip throughout pediatric development. This imaging study aimed to document and analyze the relative morphometric relationship of the sciatic nerve in the pediatric gluteal region throughout development. METHODS: The location of the sciatic nerve in relation to bony landmarks was measured in 84 pediatric magnetic resonance imaging of patients aged 0.7-15.8 years. RESULTS: The sciatic nerve was identified medial to the most lateral point of greater trochanter at the level of ischial spine and the tip of coccyx. The strong positive correlation between sciatic nerve to landmark distances and age and stature demonstrated linear variation between sciatic nerve location with age and growth of children. To predict the nerve location in the gluteal region, regression equations using patient age were created, having implications for the posterior approach of the sciatic nerve blockade in children. Clinically significant differences were found between sexes, specifically in the older age group. CONCLUSION: Despite the small sample size of younger age group, this study is the first to document the morphometric changes of the sciatic nerve in the gluteal region across pediatric development and may be useful for providing confirmatory guidelines for nerve location when ultrasound is not accessible or cannot be utilized for practice.

MRI assessment of minimally invasive anterolateral approaches in total hip arthroplasty.

INTRODUCTION: Total hip arthroplasty (THA) on a minimally invasive anterolateral (MIAL) approach frequently leads to gluteus minimus and gluteus medius lesions, and sometimes to tensor fasciae latae (TFL) denervation. We therefore developed compensatory strategies, which we assessed on pre- and post-operative MRI: 1) to assess gluteus minimus and gluteus medius fatty infiltration (FI), 2) to assess TFL FI, and 3) to assess FI in the other periarticular muscles. HYPOTHESIS: The modified MIAL approach reduces the rate of gluteus minimus and gluteus medius lesion. MATERIALS AND METHODS: A continuous prospective single-surgeon series of THA using a MIAL approach included 25 patients. Femoral implantation was performed with the hip in extension so as to distance the proximal femur from the gluteals, avoiding muscle trauma. The superior gluteal nerve branch in the space between the gluteus medius and TFL, running toward the TFL, was systematically released and protected. MRI was performed preoperatively and at 3 months and 1 year post-surgery. FI was analyzed according to the Goutallier classification in all periarticular muscles. RESULTS: One patient lacked preoperative MRI and was excluded, leaving 24 patients, for 72 MRIs. In 10/24 patients (41.7%) the gluteus minimus and in 8/24 patients (33.3%) the anterior third of the gluteus medius showed ≥2 grade increase in FI between preoperative and 1-year MRI, with significant increases in both at 3 months (p<0.001) and 1 year (p<0.001). At least a 2 grade increase in FI at 1 year was seen in 1 patient (4.2%) in the TFL, in 2 (8.3%) in the piriformis, and in 1 (4.2%) in the obturator internus. There were no significant differences in FI between preoperative, 3-month or 1-year MRI in any other periarticular muscles. CONCLUSION: Femoral implantation in hip extension did not reduce the rate of gluteal lesions, which remained frequent. In contrast, release of the superior gluteal nerve branch could be effective in conserving TFL innervation. Some rare lesions of the proximal part of the pelvi-trochanteric muscles were also observed. LEVEL OF EVIDENCE: IV, Prospective case series.

Comparative MRI assessment of three minimally invasive approaches in total hip arthroplasty.

INTRODUCTION: Minimally invasive approaches (direct anterior approach: DAA; minimally invasive anterolateral: MIAL; piriformis-sparing posterior approach: PSPA) are widely used for total hip arthroplasty (THA), with a muscle-sparing objective. There are no published comparative studies of muscle damage secondary to these approaches. The aim of the present study was to compare fatty infiltration (FI) on MRI induced by DAA, MIAL and PSPA in THA 1) in the tensor fasciae latae (TFL) and sartorius muscles, 2) in the gluteal muscles, and 3) in the pelvitrochanteric muscles. HYPOTHESIS: Greater FI is induced by DAA in anterior muscles, by MIAL in gluteal muscles and by PSPA in pelvitrochanteric muscles. MATERIALS AND METHODS: Three continuous prospective series of THA by DAA, MIAL and PSPA included 25 patients each. MRI was performed preoperatively and at 1 year postoperatively. FI was graded on the Goutallier classification in all periarticular hip muscles. Muscles showing ≥2 grade aggravation at 1 year were considered damaged. RESULTS: Nine patients whose preoperative MRI was uninterpretable were excluded. In all, 66 patients (21 DAA, 24 MIAL and 21 PSPA) with 132 MRI scans were analyzed. TFL was damaged in 2/21 DAA patients (9.5%), 1/24 MIAL patients (4.2%) and 0/21 PSPA patients (0%). There were no sartorius lesions. The anterior third of the gluteus medius was damaged in 8/24 MIAL patients (33.3%) and the gluteus minimus in 10/24 (41.7%), compared to 1/21 DAA patients (4.8%) and 0/21 PSPA patients (0%). The mid and posterior thirds of the gluteus medius and the gluteus maximus were never damaged. The piriformis muscle was damaged in 3/21 DAA patients (14.3%), 2/24 MIAL patients (8.3%) and 2/21 PSPA patients (9.5%). The obturator internus was damaged in 4/21 DAA patients (19%), 1/24 MIAL patients (4.2%) and 16/21 PSPA patients (76.2%). The obturator externus and quadratus femoris were mainly damaged in PSPA patients: respectively, 5/21 (23.8%) and 4/21 patients (19%)). CONCLUSION: The muscle-sparing properties of minimally invasive hip approaches are only theoretical. In the present series, there were rare TFL lesions with DAA and MIAL. Gluteus medius and minimus lesions were frequent in MIAL. Pelvitrochanteric muscles lesions were more frequent in PSPA, but found in all 3 approaches. These findings should help guide surgeons in their choice of approach and in informing patients about the damage these minimally invasive approaches can cause. LEVEL OF EVIDENCE: III, prospective comparative study.

Towards defining muscular regions of interest from axial magnetic resonance imaging with anatomical cross-reference: a scoping review of lateral hip musculature.

BACKGROUND: Measures of hip muscle morphology and composition (e.g., muscle size and fatty infiltration) are possible with magnetic resonance imaging (MRI). Standardised protocols or guidelines do not exist for evaluation of hip muscle characteristics, hindering reliable and valid inter-study analysis. This scoping review aimed to collate and synthesise MRI methods for measuring lateral hip muscle size and fatty infiltration to inform the future development of standardised protocols. METHODS: Five electronic databases (Medline, CINAHL, Embase, SportsDISCUS and AMED) were searched. Healthy or musculoskeletal pain populations that used MRI to assess lateral hip muscle size and fatty infiltration were included. Lateral hip muscles of interest included tensor fascia late (TFL), gluteus maximus, gluteus medius, and gluteus minimus. Data on MRI parameters, axial slice location, muscle size and fatty infiltrate measures were collected and analysed. Cross referencing for anatomical locations were made between MRI axial slice and E-12 anatomical plastinate sections. RESULTS: From 2684 identified publications, 78 studies contributed data on volume (n = 31), cross sectional area (CSA) (n = 24), and fatty infiltration (n = 40). Heterogeneity was observed for MRI parameters and anatomical boundaries scrutinizing hip muscle size and fatty infiltration. Seven single level axial slices were identified that provided consistent CSA measurement, including three for both gluteus maximus and TFL, and four for both gluteus medius and minimus. For assessment of fatty infiltration, six axial slice locations were identified including two for TFL, and four for each of the gluteal muscles. CONCLUSIONS: Several consistent anatomical levels were identified for single axial MR slice to facilitate muscle size and fatty infiltration muscle measures at the hip, providing the basis for reliable and accurate data synthesis and improvements in the validity of future between studies analyses. This work establishes the platform for standardised methods for the MRI assessment of lateral hip musculature and will aid in the examination of musculoskeletal conditions around the hip joint. Further studies into whole muscle measures are required to further optimise methodological parameters for hip muscle assessment.