Variations of the extrapsoas course of the lumbar plexus with implications for the lateral transpsoas approach to the lumbar spine: a cadaveric study.

BACKGROUND: Together with an increased interest in minimally invasive lateral transpsoas approach to the lumbar spine goes a demand for detailed anatomical descriptions of the lumbar plexus. Although definitions of safe zones and essential descriptions of topographical anatomy have been presented in several studies, the existing literature expects standard appearance of the neural structures. Therefore, the aim of this study was to investigate the variability of the extrapsoas portion of the lumbar plexus in regard to the lateral transpsoas approach. METHODS: A total of 260 lumbar regions from embalmed cadavers were utilized in this study. The specimens were dissected as per protocol and all nerves from the lumbar plexus were morphologically evaluated. RESULTS: The most common variation of the iliohypogastric and ilioinguinal nerves was fusion of these two nerves (9.6%). Nearly in the half of the cases (48.1%) the genitofemoral nerve left the psoas major muscle already divided into the femoral and genital branches. The lateral femoral cutaneous nerve was the least variable one as it resembled its normal morphology in 95.0% of cases. Regarding the variant origins of the femoral nerve, there was a low formation outside the psoas major muscle in 3.8% of cases. The obturator nerve was not variable at its emergence point but frequently branched (40.4%) before entering the obturator canal. In addition to the proper femoral and obturator nerves, accessory nerves were present in 12.3% and 9.2% of cases, respectively. CONCLUSION: Nerves of the lumbar plexus frequently show atypical anatomy outside the psoas major muscle. The presented study provides a compendious information source of the possibly encountered neural variations during retroperitoneal access to different segments of the lumbar spine.

Surco del Músculo Iliopsoas y su Relación Clínica con la Cadera. Una Revisión / Groove of the Iliopsoas Muscle and its Clinical Relationship with the Hip. A Review

El músculo iliopsoas es el principal flexor de la cadera siendo un rotador lateral accesorio de ésta, sus fibras discurren posteriores al ligamento inguinal, cruzando anteriormente a la pelvis. Este trayecto ocurre en un surco que se localiza entre la eminencia iliopúbica, medialmente y la espina iliaca anteroinferior, lateralmente. Si bien existen antecedentes de este surco, no se encuentra expresado en la terminología anatómica internacional (TAI) como un surco relevante dentro de los relieves óseos pélvicos. Este surco se encuentra asociado al tendón en diferentes disfunciones de cadera, como la cadera en resorte (coxa saltans). El objetivo de la investigación es ampliar el conocimiento clínico y anatómico de este surco y su inclusión en la terminología anatómica internacional. Dentro de los criterios de inclusión se seleccionaron artículos publicados en español e inglés que aludieron referencia al surco y/o palabras claves como, "músculo iliopsoas", "músculo psoas ilíaco", "surco iliopsoas" "surco coxal", "groove iliopsoas" y "iliopsoas muscle" "surco coxal". Los motores de búsqueda utilizados fueron Pubmed, Google Académico y Springer Link. La relevancia del surco del músculo iliopsoas abre una puerta a las discusiones respecto a su forma y profundidad, así como también un punto de referencia asociada a diferentes situaciones clínicas relacionada con este surco y probables predisposiciones a lesiones o chasquidos que ocurren en cadera. Finalmente, el conocimiento del surco para el músculo iliopsoas es importante tenerlo en consideración en investigaciones que aborden esta región, así como su terminología anatómica, relaciones anatómicas, clínicas y quirúrgicas.

SUMMARY: The iliopsoas muscle is the main hip flexor being an accessory lateral rotator of this, its fibers run posterior to the inguinal ligament, crossing anterior to the pelvis. This course occurs in a groove located between the iliopubic eminence medially and the anterior inferior iliac spine laterally. Although there are antecedents of this groove, no relevant comments are found in international anatomical terminology (IAT) as a groove within the pelvic bone reliefs. This groove is associated with the tendon in different hip dysfunctions, such as the hip snap (coxa saltans). The objective of the research is to expand the clinical and anatomical knowledge of this groove and its inclusion in international anatomical terminology. Within the inclusion criteria, articles published in Spanish and English were selected that referred to the groove and/or keywords such as "iliopsoas muscle", "iliopsoas muscle", "iliopsoas groove", "coxal groove", "iliopsoas groove". and "iliopsoas muscle" "coxal groove". The search engines used were Pubmed, Google Scholar and Springer Link. The relevance of the iliopsoas muscle groove gives way to discussions regarding its shape and depth, as well as a point of reference associated with different clinical situations related to this groove and probable predispositions to injuries or snaps that occur in the hip. Finally, knowledge of the groove for the iliopsoas muscle is important to consider in research that addresses this region, as well as its anatomical terminology, anatomical, clinical, and surgical relationships.

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.

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.

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%.

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.

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.

Association of Muscle Mass with Survival after Radical Prostatectomy in Patients with Prostate Cancer.

PURPOSE: Although muscle mass has been associated with survival in patients with various types of solid tumors, the relationship between muscle mass and survival in patients with prostate cancer remains unclear. We retrospectively investigated the association of muscle mass with survival after radical prostatectomy in patients with prostate cancer. MATERIALS AND METHODS: We reviewed the records of 2,042 patients who underwent radical prostatectomy of prostate cancer between 1998 and 2013. Muscle mass was evaluated by measuring the psoas muscle index on preoperative computerized tomography images. RESULTS: In the lowest, second, third and highest psoas muscle index quartiles the 10-year distant metastasis-free survival rate was 72.5%, 83.8%, 92.3% and 93.7% (p <0.001), the 10-year cancer specific survival rate was 85.7%, 92.1%, 96.8% and 97.6%, and the 10-year overall survival rate was 74.5%, 79.6%, 89.8% and 90.6%, respectively (each p <0.001). The psoas muscle index positively correlated with the body mass index, serum concentrations of IGFBP-3 and bioavailable testosterone, and inversely correlated with patient age, the serum SHBG concentration and the neutrophil-to-lymphocyte ratio. On multivariable analysis the psoas muscle index was independently associated with increased risks of biochemical recurrence, distant metastasis, and cancer specific and overall death. CONCLUSIONS: Low muscle mass may be associated with increased risks of recurrence and mortality in patients who undergo radical prostatectomy of prostate cancer regardless of the body mass index. Large-scale prospective studies are warranted.

Effect of Sarcopenic Overweight on Lung Transplant Based in Three-Dimensional Reconstructed Psoas Muscle Mass.

BACKGROUND: In lung transplantation, preoperative sarcopenia was reported to be associated with short-term outcomes based on cross-sectional image. This study aimed to investigate the influence of psoas muscle mass (PMM) on the operative outcome and survival using three-dimensional reconstruction of PMM and to evaluate the effect of preoperative sarcopenic overweight on postoperative outcomes and survival. METHODS: A total of 107 patients who underwent double lung transplantation in one institute from January 1, 2014, to June 30, 2017, were enrolled. The PMM was measured by Synapse 3D (Fujifilm, Seoul, Korea) visualization software based on computed tomography and three-dimensional reconstruction images. Patients were separated into two groups according to tercile of PMM (below the first tercile was defined as sarcopenia) and then subdivided according to PMM and overweight (body mass index ≥23 kg/m2). RESULTS: Sarcopenia had a significant relation with higher rate of postoperative tracheostomy (p = 0.040) and operative mortality (p = 0.023). For survival analysis, patients with sarcopenia showed a trend toward poorer outcome, but it was not significant (3-year survival rate 50.2% versus 73.2%, p = 0.054). Moreover, PMM was significantly associated with the length of mechanical ventilation (ß = -0.368, p = 0.047) and length of intensive care unit stay (ß = -0.372, p = 0.046). Sarcopenic overweight has no significant difference in terms of length of mechanical ventilation and length of intensive care unit. However, overall survival was significantly lower among patients with sarcopenic overweight than among those without sarcopenia (p = 0.026 and p = 0.024, respectively). CONCLUSIONS: Sarcopenia was associated with poorer short-term outcome, and sarcopenic overweight with poorer overall survival of lung transplant patients.

Prognostic implications of psoas muscle area in patients undergoing transcatheter aortic valve implantation.

OBJECTIVES: This study sought to assess the incremental prognostic value of the psoas muscle area in patients scheduled for transcatheter aortic valve implantation (TAVI). METHODS: A total of 1076 consecutive patients undergoing TAVI at 2 centres between 2010 and 2017 were prospectively included in this study. Computed tomography-derived cross-sectional area of the psoas muscle was measured at the superior border of the third (L3) and fourth (L4) lumbar vertebra and indexed to body surface area (PMAi) as well as stratified into tertiles. Multivariable logistic regression and Cox regression analyses were performed to investigate the value of PMAi as a predictor of 30-day and cumulative mortality. The incremental prognostic value of PMAi over the Society of Thoracic Surgeons (STS) score was assessed using a net reclassification analysis. RESULTS: The rate of 30-day mortality was 5.8% (n = 62). PMAi at the level of L3 [odds ratio 0.082, 95% confidence interval (CI) 0.011-0.589; P = 0.013] and L4 (odds ratio 0.049, 95% CI 0.005-0.536; P = 0.013) was independently associated with 30-day mortality. During a median follow-up of 435 days (interquartile range 139-904), 292 patients (27.1%) died. PMAi of L3 (hazard ratio 0.200, 95% CI 0.083-0.482; P < 0.001) and L4 (hazard ratio 0.083, 95% CI 0.029-0.235; P < 0.001) was independently associated with mortality during follow-up. The addition of PMAi to the STS score led to a net reclassification improvement for 30-day and cumulative mortality. CONCLUSIONS: PMAi emerged as a valuable outcome predictor in patients undergoing TAVI. The addition of PMAi to the established STS score led to an increase in its prognostic ability.

Anatomic Variations of the Lateral Femoral Cutaneous Nerve: Remnants of Atypical Nerve Growth Pathways Revisited by Intraneural Fascicular Dissection and a Proposed Classification.

OBJECTIVE: To trace anatomic variations of the lateral femoral cutaneous nerve (LFCN) in its intrapelvic course. METHODS: Forty cadavers (80 sides) fixed in 10% formalin solution were dissected. The following parameters were recorded: LFCN diameter and variations in its origin and number. The dissection comprised exposure and excision of the lumbar plexus, together with the roots of LFCN, followed by retrograde intraneural fascicular dissection using microsurgical instruments. RESULTS: Several types of LFCN origin from the lumbar plexus were observed. Typically, the LFCN appears as a single trunk arising from dorsal divisions of the ventral rami of the lumbar plexus. The most prevalent origin of the nerve was from the L2 and L3 roots (47 cases; 58.75%). The LFCN took an origin from the L1-L2 level in 12 cases (15%) and from the L2 nerve in 9 cases (11.25%). The main observed variations were the presence of the accessory LFCN (2 cases; 2.5%) and branching of the LFCN from the femoral nerve (6 cases; 7.5%). Communications between the LFCN and the femoral or genitofemoral nerves also were observed occasionally. An atypical course of the LFCN with respect to the anterior psoas was observed in our material in 3 of the 80 sides (3.75% of the examined LFCN specimens). CONCLUSIONS: Considerable variability in the origin and the course of the LFCN was observed, which should be taken into account during clinical assessment of nerve lesions and during surgery via transpsoas approaches to the lumbar spine.

Psoas Muscle Size Predicts Risk-Adjusted Outcomes After Surgical Aortic Valve Replacement.

BACKGROUND: Frailty is an important predictor of outcomes after cardiac surgery, but utility is limited by difficult assessment and quantification. We hypothesize that sarcopenia defined as psoas muscle cross-sectional area is a useful predictor of surgical aortic valve replacement outcomes in moderate to high-risk patients. METHODS: Moderate to high risk patients (predicted risk of mortality greater than 3%) who underwent surgical aortic valve replacement with or without coronary artery bypass were extracted from an institutional database (2009 to 2016). Psoas index was calculated as the cross-sectional area of the psoas muscle at the L4 vertebral level normalized to body surface area. Patients were stratified by sarcopenia status, defined as less than 25th sex-specific percentile. Multivariable regression analysis identified risk-adjusted associations with psoas index using The Society of Thoracic Surgeons predicted risk scores. RESULTS: Of the 240 patients included, the median predicted risk of mortality was 6%, median age 80 years, and 40% were female. Patients with (33.3%) and without (66.7%) sarcopenia had equivalent baseline risk (median predicted risk of mortality 5.7% versus 6.0%, p = 0.29). Patients with sarcopenia had higher 1-year mortality (31.9% versus 16.9% p = 0.03). Psoas index significantly predicted risk-adjusted 1-year mortality (odds ratio 0.84, p = 0.02) and long-term mortality (hazard ratio 0.92, p = 0.04), as well as risk-adjusted major morbidity, prolonged ventilation, length of stay, discharge to a facility, and hospital cost. Finally, psoas index measurements were highly reproducible (Pearson correlation coefficient 0.944). CONCLUSIONS: Psoas index is an easily obtained and reproducible measure of frailty that predicts risk-adjusted resource utilization, morbidity, and long-term mortality. Psoas index may improve procedural selection and risk adjustment in high-risk patients with aortic valve disease.

Effect of sarcopenia on the outcomes after pancreaticoduodenectomy for distal cholangiocarcinoma.

BACKGROUND: The relationship between sarcopenia and patient outcomes after pancreaticoduodenectomy (PD) for distal cholangiocarcinoma (DCC) remains unclear. We assessed the impact of sarcopenia on the outcomes after PD for DCC. METHODS: We retrospectively analysed 65 patients who underwent PD for DCC. The quality of skeletal muscle indicated by the psoas muscle mass index (PMI) were measured on pre-operative computed tomography images. The impact of pre-operative sarcopenia on short- and long-term outcomes was evaluated. RESULTS: Regarding short-term surgical outcomes, there were no marked differences between the high and low PMI groups. Regarding long-term oncological outcomes, the rates of recurrence (23.5% versus 58.3%, P = 0.011) was significantly lower in the high PMI group than in the low PMI group. Furthermore, the recurrence-free survival and disease-specific survival were longer in the high PMI group (P = 0.023 and P = 0.043, respectively). On multivariate analyses, low PMI was an independent predictor of recurrence (hazard ratio (HR) 11.06; P = 0.022) and disease-specific death (HR 11.88; P = 0.043). CONCLUSIONS: Our findings suggested an association between pre-operative sarcopenia and poor long-term oncological outcomes after PD for DCC.

Psoas Muscle Area as a Prognostic Factor for Survival in Patients with an Asymptomatic Infrarenal Abdominal Aortic Aneurysm: A Retrospective Cohort Study.

OBJECTIVES: Loss of muscle mass has been associated with poor survival in several surgical patient populations, including those with an abdominal aortic aneurysm (AAA). We wanted to replicate these findings and assess the association between psoas muscle area (PMA) and survival in patients with an asymptomatic AAA. METHODS: Patients with an asymptomatic infrarenal AAA who underwent computed tomography (CT) scanning between January 1, 2007, and December 31, 2013, were included in this single-centre retrospective cohort study. PMA was measured with thresholding on an axial image at the centre level of the third lumbar vertebra. The lowest tertile of PMA in all patients was used as a cutoff value for a low PMA. Then, in separate analyses for conservatively and surgically managed patients, survival was estimated with the Kaplan-Meier method. Differences in survival between patients with and without a low PMA were tested with the log-rank test. RESULTS: Of 228 patients, 104 were managed conservatively and 124 underwent AAA repair. Seventy-seven patients (62%) had an endovascular repair. In these 228 patients, the median PMA was 16.83 cm2, while the cutoff value for low PMA was 14.56 cm2. Patients who were managed conservatively were more often classified as having low PMA (45/104, 43%, vs. 31/124, 25%; p = .004) and were significantly older (mean 73.44 ± 9.05 years vs. 69.03 ± 7.46 years; p < .001). Low PMA was not associated with survival, either in patients managed conservatively, or in those who underwent AAA repair (p = .512 and p = .311, respectively). CONCLUSIONS: The association between low PMA and poor survival could not be replicated; in this study, low PMA was not associated with survival in patients with an asymptomatic AAA. Further research is recommended before PMA can be used for pre-operative risk stratification.

Morphometric Assessment as a Predictor of Outcome in Older Vascular Surgery Patients.

BACKGROUND: Frailty is a recognized predictor of poor outcome in patients undergoing surgical intervention. Frailty is intricately linked with body morphology, which can be evaluated using morphometric assessment via computerized tomographic (CT) imaging. We aimed to assess the predictive power of such objective assessments in a broad cohort of vascular surgical patients. METHODS: A consecutive series of patients aged over 65 years admitted to a vascular unit, who had undergone CT imaging of the abdomen, were analyzed. Demographic and patient-specific data were collated alongside admission relevant information. Outcomes included mortality, length of stay, health care-related costs, and discharge destination. Images were analyzed for 4 morphometric measurements: (1) psoas muscle area, (2) mean psoas density, (3) subcutaneous fat depth, and (4) intra-abdominal fat depth, all taken at the level of the fourth lumbar vertebra. RESULTS: Two hundred and ten patients were initially analyzed. Forty-four patients had significant retroperitoneal and abdominal abnormalities that limited appropriate CT analysis. Decreased subcutaneous fat depth was significantly associated with mortality, readmission within 12 months, and increased cost of health care (P < 0.01, adjusted for confounders). Psoas muscle area was significantly associated with readmission-free survival. CONCLUSIONS: Morphometric analysis predicts poorer outcome in a broad cohort of vascular surgery patients. Such assessment is likely to enhance patient counseling regarding individual risk as well as enhancing the ability to undertake risk-modified surgical audit.

Ultrasound-guided femoral and obturator nerves block in the psoas compartment in dogs: anatomical and randomized clinical study.

OBJECTIVE: To evaluate intraoperative and postoperative efficacy of ultrasound (US)-guided femoral (FN) and obturator (ON) nerves block, in the iliopsoas muscle compartment (IPM), using an in-plane technique. STUDY DESIGN: Anatomical research and randomized, prospective, 'blinded' clinical study. ANIMALS: Six dog cadavers and 20 client-owned dogs undergoing tibial plateau levelling osteotomy (TPLO) surgery. METHODS: In phase 1, anatomical dissections and US imaging of the IPM were performed to design an US-guided nerve block involving the FN and ON simultaneously. The technique was considered successful if new methylene blue solution injection (0.1 mL kg-1) stained FN-ON for ≥2 cm. In phase 2, the US-guided nerve block designed in phase 1, combined with US-guided sciatic nerve (ScN) block, was performed in 20 dogs undergoing TPLO surgery. Patients were assigned randomly to one of two treatment groups: ropivacaine 0.3% (R3, n=10) and ropivacaine 0.5% (R5, n=10) at a volume of 0.1 mL kg-1 for each nerve block. Intraoperative success rate (fentanyl requirement < 2.1 mcg kg-1 hour-1) and postoperative pain score [Short Form-Glasgow Composite Measure Pain Scale (SF-GCMPS) ≥ 5/20] were evaluated. RESULTS: In phase 1, the US image of FN-ON was detected between L6 and L7. In-plane needling technique produced a staining of >4 cm in six of six cases. No abdominal or epidural dye spread was found. In phase 2, median fentanyl infusion rates were 0.5 (0.0-0.9) µg kg-1 hour-1 for R3 and 0.6 (0.0-2.2) µg kg-1 hour-1 for R5. At 9 and 11 hours after the peripheral nerve blocks, an SF-GCMPS ≥ 5 was observed for R3 and R5, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The US-guided FN-ON block in the IPM, using an in-plane technique, combined with US-guided ScN block, provided sufficient analgesia to minimize the use of fentanyl during TPLO surgery. A longer postoperative analgesia was observed in group R5 compared with R3.