Development and validation of a reliable method for automated measurements of psoas muscle volume in CT scans using deep learning-based segmentation: a cross-sectional study.

OBJECTIVES: We aimed to develop an automated method for measuring the volume of the psoas muscle using CT to aid sarcopenia research efficiently. METHODS: We used a data set comprising the CT scans of 520 participants who underwent health check-ups at a health promotion centre. We developed a psoas muscle segmentation model using deep learning in a three-step process based on the nnU-Net method. The automated segmentation method was evaluated for accuracy, reliability, and time required for the measurement. RESULTS: The Dice similarity coefficient was used to compare the manual segmentation with automated segmentation; an average Dice score of 0.927 ± 0.019 was obtained, with no critical outliers. Our automated segmentation system had an average measurement time of 2 min 20 s ± 20 s, which was 48 times shorter than that of the manual measurement method (111 min 6 s ± 25 min 25 s). CONCLUSION: We have successfully developed an automated segmentation method to measure the psoas muscle volume that ensures consistent and unbiased estimates across a wide range of CT images.

Association between psoas major muscle mass and CPET performance and long-term survival following major colorectal surgery: A retrospective cohort study.

OBJECTIVES: To evaluate whether computed tomography (CT)-derived psoas major muscle measurements could predict preoperative cardiopulmonary exercise testing (CPET) performance and long-term mortality in patients undergoing major colorectal surgery and to compare predictive performance of psoas muscle measurements using 2D approach and 3D approach. METHODS: A retrospective cohort study compliant with STROCSS standards was conducted. Consecutive patients undergoing major colorectal surgery between January 2011 and January 2017 following CPET as part of their preoperative assessment were included. Regression analyses were modelled to investigate association between the CT-derived psoas major muscle mass variables [total psoas muscle area (TPMA), total psoas muscle volume (TPMV) and psoas muscle index (PMI)] and CPET performance and mortality (1-year and 5-year). Discriminative performances of the variables were evaluated using Receiver Operating Characteristic (ROC) curve analysis. RESULTS: A total of 457 eligible patients were included. The median TPMA and TPMV were 21 â€‹cm2 (IQR: 15-27) and 274 â€‹cm3 (IQR: 201-362), respectively. The median PMI measured via 2D and 3D approaches were 7 â€‹cm2/m2 (IQR: 6-9) and 99 â€‹cm3/m2 (IQR: 76-120), respectively. The risks of 1-year and 5-year mortality were 7.4% and 27.1%, respectively. Regression analyses showed TPMA, TPMV, and PMI can predict preoperative CPET performance and long-term mortality. However, ROC curve analyses showed no significant difference in predictive performance amongst TPMA, TPMV, and PMI. CONCLUSION: Radiologically-measured psoas muscle mass variables may predict preoperative CPET performance and may be helpful with informing more objective selection of patients for preoperative CPET and prehabilitation.

How Prone Position Affects the Anatomy of Lumbar Nerve Roots and Psoas Morphology for Prone Transpsoas Lumbar Interbody Fusion.

BACKGROUND: Lumbar nerve root injury is a serious complication of transpsoas lumbar interbody fusion. Researchers have reported lumbar nerve roots and psoas muscle anatomy in the supine position, but no previous studies have used prone position magnetic resonance imaging to evaluate these structures. OBJECTIVE: The purpose of this study was to show the changes in the lumbar nerve roots and psoas muscle related to the lumbar intervertebral disc using supine and prone magnetic resonance imaging. METHODS: Thirty volunteers without spinal or hip abnormalities were included in this observational study. Each volunteer underwent supine and prone lumbosacral magnetic resonance imaging without abdominal compression. The lumbar nerve roots, psoas muscle, aorta, superior vena cava, common iliac artery, and vein were identified at each lumbar disc level. The lumbar plexus position relative to the transpsoas working channel, psoas muscle morphology, and great vessels relative to the anterior and posterior aspects of the annulus fibrosus in the axial plane were measured by 1 observer, and intraobserver reliability was calculated. RESULTS: Fifteen men and 15 women were included in this study. There were no significant differences in the axial image distance of the lumbar nerve roots, psoas/disc ratio, and location of other related anatomy between the supine and prone positions. More lordosis (both upper and lower arc lordosis) was noted in the prone position (51.98° ± 10.54°) than in the supine position (42.12° ± 10.13°). CONCLUSIONS: Lumbar nerve roots, psoas morphology, and great vessel position were not affected by the prone position compared with the supine position.

Identification of Sarcopenia in Elderly Trauma Patients: The Value of Clinical Competency and Experience.

INTRODUCTION: There is currently no standard definition of sarcopenia, which has often been associated with frailty. A commonly cited surrogate measure of sarcopenia is psoas muscle size. The purpose of this prospective study is to assess medical providers' capabilities to identify frail elderly trauma patients and consequent impact on outcomes after intensive care unit admission. METHODS: Trauma intensive care unit patients over the age of 50 were enrolled. A preadmission functional status questionnaire was completed on admission. Attendings, residents, and nurses, blinded to their patient's sarcopenic status, completed surveys regarding 6-month prognosis. Chart review included cross-sectional psoas area measurements on computerized tomography scan. Finally, patients received phone calls 3 and 6 months after admission to determine overall health and functional status. RESULTS: Seventy-six participants had an average age of 70 years and a corrected psoas area of 383 ± 101 mm2/m2. Injury Severity Score distribution (17.2 ± 8.9) was similar for both groups. Patients also had similar preinjury activities of daily living. Both groups had similar hospital courses. While sarcopenic patients were less likely to be predicted to survive to 6 months (60% vs. 76%, P = 0.017), their actual 6-month mortality was similar (22% vs. 21%, P = 0.915). CONCLUSION: Despite similar objective measures of preadmission health and trauma injury severity, medical providers were able to recognize frail patients and predicted they would have worse outcomes. Interestingly, sarcopenic patients had similar outcomes to the control group. Additional studies are needed to further delineate factors influencing provider insight into functional reserves of elderly trauma patients.

Revision of hip flexor anatomy and function in modern humans, and implications for the evolution of hominin bipedalism.

Hip flexor musculature was instrumental in the evolution of hominin bipedal gait and in endurance running for hunting in the genus Homo. The iliacus and psoas major muscles were historically considered to have separate tendons with different insertions on the lesser trochanter. However, in the early 20th century, it became "common knowledge" that the two muscles insert together on the lesser trochanter as the "iliopsoas" tendon. We revisited the findings of early anatomists and tested the more recent paradigm of a common "iliopsoas" tendon based on dissections of hips and their associated musculature (n = 17). We rediscovered that the tendon of the psoas muscle inserts only into a crest running from the superior to anterior aspect of the lesser trochanter, separate from the iliacus. The iliacus inserts fleshly into the anterior portion of the lesser trochanter and into an inferior crest extending from it. We developed 3D multibody dynamics biomechanical models for: (a) the conjoint "iliopsoas" tendon hypothesis and (b) the separate insertion hypothesis. We show that the conjoint model underestimates the iliacus' capacity to generate hip flexion relative to the separate insertion model. Further work reevaluating the primate lower limb (including human) through dissection, needs to be performed to develop those datasets for reconstructing anatomy in fossil hominins using the extant phylogenetic bracket approach, which is frequently used for tetrapods clades outside of paleoanthropology.

A Crucial But Neglected Anatomical Factor Underneath Psoas Muscle and Its Clinical Value in Lateral Lumbar Interbody Fusion-The Cleft of Psoas Major (CPM).

OBJECTIVE: To describe the anatomical feature positioned beneath the psoas muscle at the lateral aspect of the lower lumbar, and to create a new location system to identify the risk factors of lateral lumbar interbody fusion. METHODS: Six cadavers were dissected and analyzed. The anatomy and neurovascular distribution beneath the psoas major from L3 to S1 was observed and recorded, with particular focus on the L4/5 disc and below. The psoas major surface was divided homogeneously into four parts, from the anterior border of psoas major to the transverse process. The cranial-to-caudal division was from the lower edge of the psoas muscle attachment on the L4 vertebrae to the upper part of the S1 vertebrae, and was divided into five segments. Then a grid system was used to create 20 grids on the psoas major surface, from the anterior border of the muscle to the transverse process and from L4 to superior S1 , which was used to determine the anatomical structures' distribution and relationship beneath the psoas major. RESULTS: A cleft was identified beneath the psoas major, from the level of L4/5 downwards. It was filled with loose connective tissue and neurovascular structures. We termed it the cleft of psoas major (CPM). The sympathetic trunk, ascending lumbar vein, iliolumbar vessels, obturator nerve, femoral nerve and occasionally the great vessels are contained within the CPM, although there is significant interpersonal variation. The grid system on the psoas major surface helped to identify the anatomical structures in CPM. There was a considerably lower frequency of occurrence of neurovascular structures in the grids of I/II at the L4/5 level where can be considered the "safe zones" for the lateral lumbar interbody fusion. In contrast, the distribution of neurovascular structures at the L5 S1 level is dense, where the operation risk is high. CONCLUSION: The CPM exists lateral to the vertebral surface from L4 and below. Although the occurrence and distribution of neurovascular structures within the CPM is complex and varies greatly, it can provide a potential cavity for visualization during lateral lumbar interbody fusion. Using psoas major as a reference, this novel grid system can be used to identify the risk factors in CPM and thus identify a safe entry point for surgery.

Anteroinferior Psoas Technique for Oblique Lateral Lumbar Interbody Fusion: Technical Note and Case Series.

OBJECTIVE: The aim of the present paper was to evaluate cases of lumbar degenerative diseases treated with oblique lateral interbody fusion (OLIF) using a modified lateral approach (i.e. anteroinferior psoas exposure under direct vision) and to analyze the effect and safety of this approach. METHODS: From June 2016 to April 2019, a total of 226 patients with an average age of 65.5 ± 16.2 years (98 men and 128 women) with degenerative lumbar diseases who underwent the AIP approach of OLIF were followed up and analyzed retrospectively. Data concerning operative and clinical parameters were collected, including operative time, intraoperative estimated blood loss, duration of postoperative hospital stay, and time to ambulation after surgery. For the assessment of clinical outcomes, the visual analogue scale (VAS) score (for back pain) and the Oswestry disability index (ODI) were calculated. Complications were also recorded as surgical exposure approach-related complications. More than 6 months after surgery, 132 patients consented to having MRI examinations to evaluate the psoas muscle atrophy when they were followed up. RESULTS: The mean operative time was 82.5 ± 31.6 min. The mean operative time for each segment of OLIF was 43.3 ± 15.5 min. The mean blood loss was 48.0 ± 11.6 mL. The mean blood loss for each segment of OLIF was 25.3 ± 10.1 mL. No patients needed blood transfusion intraoperatively or postoperatively. The mean hospital stay was 4.1 ± 2.1 days. All patients were followed up for 12-31 months (mean 18.2 months). Clinical assessment showed that the VAS and ODI scores at 6 months after surgery were markedly lower than the preoperative scores (P < 0.001) but did not differ from the scores at the final follow-up (P > 0.05). There was no significant difference in percentage changes of the cross-sectional area of the lean psoas muscle and the T2 signal intensity ratio of gross psoas to quadratus lumborum muscles between the left side (operative side) and the right side (nonoperative side) (P > 0.05). A total of 11 surgical exposure approach-related complications were reported, with an incidence of 4.9%: transient thigh pain/numbness, psoas weakness (2.2%), sympathetic chain injury (1.3%), cage subsidence (0.9%), and segmental artery injury (0.4%). There was no permanent motor neurological deficit, and no injury of vascular, ureter or peritoneal membranes. CONCLUSION: The anteroinferior psoas approach for OLIF is safe and can preserve the psoas and lumbar plexus.

Skeletal Muscle Characteristics May Inform Preprocedural Risk Stratification in Transcatheter Aortic Valve Replacement Patients.

OBJECTIVES: Low psoas muscle mass previously has been associated with mortality after transcatheter aortic valve replacement (TAVR). Evidence from other clinical disciplines suggests that psoas density (PD) may be a better predictor than psoas muscle cross-sectional area indexed to body surface area (PI). The authors hypothesized that PD would be more strongly correlated with patient discharge disposition and survival after TAVR than PI. DESIGN: The authors performed a single-center, retrospective study of TAVR patients from 2013 to 2016. PI and PD were assessed at the third lumbar spine level using computed tomography imaging. Propensity-score matching was used to investigate the association of PI and PD with discharge disposition and mortality. SETTING: Tertiary university hospital PARTICIPANTS: Cohort of 245 TAVR patients. INTERVENTIONS: None MEASUREMENTS AND MAIN RESULTS: A total of 245 patients met inclusion criteria. Following propensity score matching, patients with PI <4 cm2/m2 and PD <25 Hounsfield units (HU) were less likely to survive and to be discharged home compared with patients with PI ≥4 cm2/m2 or PD >25 HU. After repeating the propensity score matching with PI as a covariable, PD remained associated with mortality (90 days: odds ratio [OR] 4.59; 95% confidence interval [CI] 2.96-10.31, p < 0.001, 1 year: OR 6.14; 95% CI 3.45-28.57, p = 0.01, 3 years: OR 4.55; 95% CI 2.41-40.00, p = 0.03). CONCLUSIONS: PD may be more relevant than PI in risk stratification for TAVR patients.

Lateral Lumbar Interbody Fusion at L4-5: A Morphometric Analysis of Psoas Anatomy and Cage Placement.

BACKGROUND: The ventral elevation (VE) of the psoas from the vertebral column as seen on axial magnetic resonance imaging has been suggested as a preclusion of a safe working zone for lateral lumbar interbody fusion (LLIF) at L4-5. However, no quantitative study has been conducted to verify this. METHODS: L4-5 LLIF was attempted using 22-mm wider cages whenever feasible over 18-mm standard cages in a consecutive series of 62 patients. The degree of VE of the psoas measured from the anterior border of the L5 endplate and the anteroposterior cage position measured from the posterior vertebral border to the center of the cage normalized to the anteroposterior width of the L5 endplate were recorded on axial images. RESULTS: LLIF was successfully performed in all cases despite 18 patients (29%) harboring elevated psoas. Standard cage was applied in 25 (40%) patients due to nerve proximity. Wider cage was applied equally frequent in both elevated (56%) and nonelevated groups (60%, P = 0.78). The mean cage position was found to be 0.54 ± 0.10 (standard deviation) and no difference was detected between the elevated (0.54 ± 0.11) and nonelevated (0.53 ± 0.10, P = 0.78) groups. Multivariate analyses and receiver operating characteristic analysis demonstrated that VE displayed low performance in predicting the choice of cages. CONCLUSIONS: LLIF is feasible in patients with ventrally elevated psoas, and the choice of cages does not appear to be influenced by the location of the psoas. Relying on the rising psoas sign on magnetic resonance imaging as a case selection criterion may unjustly exclude patients from LLIF.

Iliopsoas the Hidden Muscle: Anatomy, Diagnosis, and Treatment.

The iliopsoas is a deep muscle group which anatomically connects the spine to the lower limbs. It is composed of the iliacus, psoas major, and psoas minor muscles. The iliopsoas functions as the primary hip flexor. Because the iliopsoas is important for daily activities, including sports, impairments and pathology associated with this muscle group can cause significant limitations. Evaluating pathology associated with the iliopsoas muscle group can be challenging because the patient's complaints are often vague and difficult to discern from other hip problems. This article will review relevant anatomy, discuss common pathologies, present clinical based examination methods, and outline conservative treatment interventions focusing on manual therapy and active exercises.

Pre-sarcopenia is the prognostic factor of overall survival in early-stage hepatoma patients undergoing radiofrequency ablation.

Sarcopenia might have impact on the outcome of patients with hepatoma carcinoma (HCC). This study was to determine whether pre-sarcopenia is associated with the outcome of HCC patients undergoing radiofrequency ablation (RFA).Patients with newly diagnosed HCC undergoing RFA were enrolled. We excluded patients without pre-RFA abdominal computed tomography or with incomplete ablation. Psoas muscle area index was calculated at the mid-lumbar 3 level of computed tomography images with the manual trace method. Pre-sarcopenia was defined as psoas muscle area index less than 4.24 and 2.50 cm/m for males and females respectively. The demographics and clinical characteristics were recorded before RFA.All patients were followed regularly until death or end of 2018. A total of 136 patients, including - BCLC stage 0 (n = 44, 32.4%) and - stage A (n = 92, 67.6%), were enrolled (males/females: 78/58, age: 65.4 years) with a mean follow-up period of 3.84 years. There were 75 patients (55.1%) with HCC recurrence and 47 patients (34.6%) with mortality during follow-up. Twenty-two (16.2%) patients were diagnosed with pre-sarcopenia. Multivariate analysis showed pre-sarcopenia (HR: 2.110 (1.092-4.078); P = .026) was the only factor significantly associated with overall survival (OS); however, there were no factors associated with HCC recurrence.For patients without and with pre-sarcopenia, the 1-, 3-, and 5-year OS rates were 92.0%, 77.6%, 68.9%, and 81.8%, 54.5%, 44.1% respectively (P = .007). For early-stage HCC patients undergoing RFA, pre-sarcopenia is the prognostic factor of OS, but not of recurrence, with a worse 5-year OS rate of 44.1%.

Relationship of the Obturator Nerve and Psoas Major: Anatomic Study with Application to Avoiding Iatrogenic Injuries.

BACKGROUND: The proximal course of the obturator nerve as related to the psoas major has been described differently among various authors. Because this relationship is important for better understanding of clinical presentations and during surgical approaches, this study aimed to elucidate this anatomy via cadaveric dissection. METHODS: Twenty obturator nerves from 10 white cadaveric specimens underwent dissection. Observations were made of the relationship between the nerve and psoas major muscle. RESULTS: On all sides, the obturator nerve descended posterior to the psoas major and never through it. CONCLUSIONS: These results might be important to clinicians who interpret radiology of this region, to clinicians who treat patients with presumed obturator compression syndromes, or to surgeons who operate near the intracavitary part of the obturator nerve.

Bilateral branching variants ofinternal and external iliac arteries

During a routine female cadaveric dissection, we found an unusual bilateral pelvic branching pattern of the internal and external iliac arteries. The vaginal and middle rectal arteries had a common origin from the right internal pudendal artery. An aberrant obturator artery arises from both external iliac arteries. A right aberrant obturator artery gives a small branch to the back of the pubic bone. The left inferior epigastric artery arises from the common trunk of the external iliac artery with the aberrant obturator artery. Knowledge of arterial variations helps to reduce the internal hemorrhage during abdominal and pelvic surgeries

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Pre-operative psoas major measurement compared to P-POSSUM as a prognostic indicator in over-80s undergoing emergency laparotomy.

INTRODUCTION: Emergency laparotomy in patients over the age of 80 is associated with high morbidity and mortality. Accurate risk prediction in this patient population is desirable. Sarcopenia has been shown to be associated with outcome in multiple clinical settings and the psoas major muscle as measured on computed tomography (CT) imaging has been demonstrated as a marker of sarcopenia. We aim to assess the use of psoas major measurement on pre-operative CT as a prognostic indicator in over-80s undergoing emergency laparotomy and compare this measurement to P-POSSUM. METHODS: A retrospective interrogation of the prospectively collected National Emergency Laparotomy Database including all over-80s undergoing emergency laparotomy between January 2014 and September 2016 was conducted. Demographic, operative data and P-POSSUM data were collected and analysed. Computed tomography (CT) images were accessed and analysed, and cross-sectional areas of psoas major and the corresponding lumbar vertebral body at the level of the L3 inferior end plate were calculated. The ratio of psoas major-to-L3 cross-sectional area (PM:L3) was calculated for each patient. Mann-Whitney U test and receiver-operating characteristics (ROC) curves were used for statistical analysis. RESULTS: One hundred and three over-80s underwent emergency laparotomy. Male:female ratio was 60:43. Median age was 84 years (range 80-98 years). 30-day mortality was 19.4%.90-day mortality was 25.2%. Median PM:L3 ratio in patients who died as an inpatient was 0.3 and PM:L3 ratio in patients who survived to discharge was 0.52 (p < 0.0001). Median PM:L3 ratio in patient who died within 30 days post-op was 0.28 and 0.48 in those patients who survived to 30 days (p < 0.0001). Median PM:L3 ratio in patient who died within 90 days post-op was 0.28 and 0.51 in those patients who survived to 90 days (p < 0.0001). ROC analysis gave an area under the curve (AUC) of 0.85 for in-patient mortality, 0.86 for 30-day mortality, and 0.88 for 90-day mortality. ROC analysis for P-POSSUM in this data set demonstrated an AUC of 0.51 for in-patient mortality and 0.75 for 30- and 90-day mortality. CONCLUSION: CT imaging of the abdomen and pelvis is routinely used in over-80s prior to emergency laparotomy making PM:L3 calculation feasible for the majority of patients in this group. PM:L3 ratio is a useful prognostic indicator for prediction of mortality in patients over the age of 80. PM:L3 is superior to the P-POSSUM score in this series.

The Oblique Corridor at L4-L5: A Radiographic-Anatomical Study Into the Feasibility for Lateral Interbody Fusion.

STUDY DESIGN: Cross-sectional radioanatomical study. OBJECTIVE: The aim of this study was to analyze the prevalence, size, and location of the oblique corridor (OC), and the morphology of the psoas muscle at the L4-L5 disc level. SUMMARY OF BACKGROUND DATA: Lateral lumbar interbody fusion via the OC has the advantage of avoiding injury to the psoas muscle and lumbar plexus. However, the varying anatomy of major vascular structures and the iliopsoas may preclude a safe oblique access to the L4-L5 level. METHODS: Five hundred axial magnetic resonance images of the L4-L5 disc level were shortlisted. OCs were categorized into four grades: Grade 0 = no corridor, Grade 1 = small corridor (≤1 cm), Grade 2 = moderate corridor (1-2 cm) and Grade 3 = large corridor (>2 cm). OC location was labeled as antero-oblique, oblique, or oblique-lateral. Psoas morphology was categorized based on a modified Moro's classification, where the anterior section was further subdivided into types AI-AIV. Oblique approach was considered nonviable either when there was no corridor due to vascular obstruction (Grade 0) or when the psoas was high-rising (Types AII-AIV). RESULTS: 10.5% of the selected 449 patients had no measurable OC (grade 0) at the L4-L5 level. There were 35% and 37.2% patients with a grade 1and 2 OC, respectively. The location of the OC was anterior oblique, oblique, and oblique lateral in 3.7%, 89.6%, and 6.7%, respectively. According to the modified Moro's classification, 19.4% had a high-rising psoas. Predominantly, psoas was either in line with the disc (Type I; 30.7%) or low-rising (Type AI; 47.4%). CONCLUSION: Twenty-five percent of the patients did not have an accessible OC either due to obstruction by vascular structures or due to a high-rising psoas. Hence, proper evaluation of the relevant anatomy preoperatively is recommended for early adopters of this technique, as varying anatomy precludes universal suitability of oblique lateral interbody fusion for the L4-L5 level. LEVEL OF EVIDENCE: 3.

A discrete element model to predict anatomy of the psoas muscle and path of the tendon: Design implications for total hip arthroplasty.

BACKGROUND: The accurate estimation of a muscle's line of action is a fundamental requirement in computational modelling. We present a novel anatomical muscle wrapping technique and demonstrate its clinical use on the evaluation of the Psoas muscle mechanics in hip arthroplasty. METHODS: A volume preserving, spring model to parameterize muscle anatomy changes during motion is presented. Validation was performed by a CT scan of a cadaver model in multiple positions. The predicted psoas musculotendinous path was compared with the actual imaging findings. In a second stage, psoas kinetics were compared between a conventional versus a resurfacing hip arthroplasty during gait. FINDINGS: Anatomy prediction error was found to be 2.12 mm on average (SD 1.34 mm). When applied to psoas mechanics during walking, the muscle was found to wrap predominantly around the femoral head providing a biomechanically efficient and nearly constant moment arm for flexion during the entire gait cycle. However, this advantage was found to be lost in small diameter hip arthroplasty designs resulting in an important mechanical disadvantage. The moment arm for flexion, was on average 36% (SD 0.03%) lower in the small diameter conventional hip arthroplasty as compared to the large diameter head of the hip resurfacing and this difference was highly significant. (p < 0.001). INTERPRETATION: Despite the shortcomings of an "in silico" and cadaveric study, our findings are in accordance with previous clinical and gait studies. Furthermore, the findings are strongly in favour of large diameter implant designs, warranting their further development and optimisation.

Analysis of pre- and intraoperative clinical for successful operating room extubation after living donor liver transplantation: a retrospective observational cohort study.

BACKGROUND: Early extubation after liver transplantation is safe and accelerates patient recovery. Patients with end-stage liver disease undergo sarcopenic changes, and sarcopenia is associated with postoperative morbidity and mortality. We investigated the impact of core muscle mass on the feasibility of immediate extubation in the operating room (OR) after living donor liver transplantation (LDLT). METHODS: A total of 295 male adult LDLT patients were retrospectively reviewed between January 2011 and December 2017. In total, 40 patients were excluded due to emergency surgery or severe encephalopathy. A total of 255 male LDLT patients were analyzed in this study. According to the OR extubation criteria, the study population was classified into immediate and conventional extubation groups (39.6 vs. 60.4%). Psoas muscle area was estimated using abdominal computed tomography and normalized by height squared (psoas muscle index [PMI]). RESULTS: There were no significant differences in OR extubation rates among the five attending transplant anesthesiologists. The preoperative PMI correlated with respiratory performance. The preoperative PMI was higher in the immediate extubation group than in the conventional extubation group. Potentially significant perioperative factors in the univariate analysis were entered into a multivariate analysis, in which preoperative PMI and intraoperative factors (i.e., continuous renal replacement therapy, significant post-reperfusion syndrome, and fresh frozen plasma transfusion) were associated with OR extubation. The duration of ventilator support and length of intensive care unit stay were shorter in the immediate extubation group than in the conventional extubation group, and the incidence of pneumonia and early allograft dysfunction were also lower in the immediate extubation group. CONCLUSIONS: Our study could improve the accuracy of predictions concerning immediate post-transplant extubation in the OR by introducing preoperative PMI into predictive models for patients who underwent elective LDLT.

Iliolumbar Vein: Anatomy and Surgical Importance During Lateral Transpsoas and Oblique Approaches to Lumbar Spine.

OBJECTIVE: Safe surgical approaches to the anterolateral lumbar spine require a good working knowledge of the anatomy and anatomic variations of this region. As the iliolumbar vein is in the vicinity of both oblique and lateral transpsoas approaches to the lower lumbar spine, the following study was performed to better elucidate its anatomy, variations, and position during such surgical procedures. METHODS: Fifteen (30 sides) fresh frozen adult cadavers underwent dissection of the iliolumbar vein (ILV). The origin, course, variants, relations, and morphometrics of each vein were documented. Fluoroscopy of the vessels was performed. Lastly, anterior oblique and lateral transpsoas approaches to the lumbar spine were carried out in order to evaluate for potential ILV injury. RESULTS: An ILV was found on all but 2 sides (93.3%). It arose as a common trunk from the common iliac vein on 14 sides. Left ILVs tended to have a more distal origin than right ILVs. ILVs had a mean length of 3.7 cm and a mean width of 0.9 cm and were significantly larger on right versus left sides (P < 0.05). Left-sided ILVs tended to have more branches than right-sided veins. The majority of vertical branches of the ILV traveled anterior to the ventral rami of the lumbar spinal nerves, most commonly L4. The ILV and, in particular, its vertical branches coursed next to the L4 and L5 vertebrae. CONCLUSIONS: The ILV should be considered during both oblique and lateral transpsoas approaches to the lumbar spine.

Psoas and Paraspinous Muscle Measurements on Computed Tomography Predict Mortality in European Americans with Type 2 Diabetes Mellitus.

BACKGROUND: Appendicular skeletal muscle mass index and muscle attenuation (density) are negatively associated with mortality in European-derived populations. OBJECTIVES: The present analyses assessed association between axial skeletal muscle density and muscle index with mortality in European Americans with type 2 diabetes mellitus (T2D). DESIGN: Single-center observational study. SETTING: Diabetes Heart Study. PARTICIPANTS: 839 European Americans with T2D. METHODS: Computed tomography-measured psoas and paraspinous muscle mass index (cross sectional area/height2) and radiographic density (Hounsfield Units) were assessed in all participants. A Cox proportional hazards model was computed. The fully-adjusted model included covariates age, sex, body mass index, smoking, alcohol use, diabetes duration, insulin use, hormone replacement therapy (women), prevalent cardiovascular disease (CVD), hypertension, and coronary artery calcified atherosclerotic plaque mass score. Deaths were recorded in the National Death Index data through December 31, 2015. RESULTS: Participants included 428 women and 411 men with median (25th, 75th quartile) age 62.8 (56.1, 69.1) years and diabetes duration 8.0 (5.0, 14.0) years. After 11.9 (9.4, 13.3) years of follow-up, 314 (37.4%) of participants were deceased. In the fully-adjusted model, psoas muscle density (hazard ratio [HR] 0.81, p<0.001), psoas muscle index (HR 0.82, p=0.008), and paraspinous muscle density (HR 0.85, p=0.003) were inversely associated with mortality. Paraspinous muscle index was not significantly associated with mortality (HR 0.90, p=0.08). Results did not differ significantly between men and women. CONCLUSIONS: In addition to established risk factors for mortality and CVD, higher psoas muscle index, psoas muscle density, and paraspinous muscle density were significantly associated with lower all-cause mortality in European Americans with T2D.

Imaging Anatomic Research of Oblique Lumbar Interbody Fusion in a Chinese Population Based on Magnetic Resonance.

OBJECTIVE: To provide anatomic evidence of preoperative assessment of oblique lumbar interbody fusion (OLIF) for Chinese patients. METHODS: From the hospital picture archiving and communication system, 400 lumbar magnetic resonance imaging studies of adults performed between November 2016 and January 2017 were selected. L2-3, L3-4, L4-5, and L5-S1 transverse and sagittal images were studied, and anatomic parameters associated with OLIF surgery, including bare window and psoas window, were measured and recorded. SPSS software was used for data summarization, sorting, and analysis to explore the significance of various anatomic parameters. RESULTS: OLIF surgical corridors to the L2-S1 discs were found in most magnetic resonance imaging scans studied. The size of the psoas affects the difficulty of psoas muscle traction. It is relatively easy to perform OLIF surgery in older women. Most of the human iliac arteries were bifurcated and aggregated in front of the L4-5 intervertebral disc. The lower the aggregate level of the common iliac vein, the less likely it was to have the OLIF surgical corridor in the L5-S1 segment. The most frequently used lengths for a lumbar interbody cage for OLIF for Chinese patients are 50 mm and 55 mm. CONCLUSIONS: OLIF can be a good choice for lumbar intervertebral fusion, including L5-S1 segment, in most Chinese patients. Older women are likely to have more scope of OLIF surgery. As a routine preoperative examination, lumbar magnetic resonance imaging is of great importance to OLIF surgery preoperative assessment.