Sartorius Muscle Research Articles

Surgical Anatomy of the Rectus-Sparing Approach for Periacetabular Osteotomy: A Cadaveric Study.

The Bernese periacetabular osteotomy (PAO) is a widely used technique for the management of acetabular dysplasia and other hip deformities in adolescents and young adults. Originally, the approach was described with a release of both origins of the rectus femoris muscle1. In the more recently described rectus-sparing approach, both heads remain attached2,3. It has been proposed that this modification may decrease pain, ease postoperative rehabilitation, and avoid heterotopic ossifications, without limitations of the surgical overview. Both the original and the rectus-sparing approach are modifications of the Smith-Petersen approach. The skin incision and further dissection remain identical in both approaches for the protection of the lateral femoral cutaneous nerve, the osteotomy of the anterior superior iliac spine (or takedown of the inguinal ligament), the exposure of the iliac fossa, and the medial retraction of the abdominal and iliopsoas muscles. In both variants, the further dissection traverses the iliopectineal bursa. In contrast to the original approach, in which the rectus muscle becomes part of the medial flap after releasing both heads, the rectus-sparing approach involves the undetached rectus muscle becoming part of the lateral flap while the medial flap includes the sartorius and iliacus-iliocapsularis muscles. The anterior capsule and deep structures can be accessed through the interval between the rectus femoris and iliopsoas muscles or lateral to the rectus muscle. The remaining surgical steps are again similar in both techniques. According to preference, the surgeon starts with the pubic osteotomy or with the ischial cut first, the latter avoiding additional bleeding from the pubic osteotomy. For the ischial osteotomy, the bone is accessed by making an anteroposterior tunnel between the medial capsule and the iliopsoas tendon anteriorly and between the medial capsule and the obturator externus muscle posteriorly. While the ischial osteotomy is an incomplete separation, the pubic osteotomy is a complete separation. It sections the superior pubic ramus medial to the iliopectineal eminence, in a somewhat oblique fashion. The third and fourth cuts are made in the iliac bone in such a way as to keep the posterior column intact. By connecting the posterior iliac and ischial cuts as the last osteotomy step, the acetabulum is freed and repositioned as needed. The aim of our cadaver dissection is primarily to describe part of the rectus-sparing approach and to test this modification for eventual disadvantages over the classic approach. The remaining steps of the procedure correspond to the approach as described earlier1,4, appreciating that several modifications of the procedure are in use. Nonsurgical treatment may be an alternative in borderline dysplasia; however, it needs to be reconsidered and eventually changed to surgical treatment when symptoms persist or come back. Other current techniques for surgical treatment of adolescent and adult hip dysplasia include triple and rotational or spherical osteotomies5-7. The Bernese PAO is performed through a single incision. All cuts are performed from the inner side of the pelvis, avoiding interference with the vascularity of the acetabular and periacetabular bone, which mainly comes from the outside of the pelvis8. The procedure needs minimal hardware for fixation, and partial weight-bearing can be allowed. The PAO provides a wide range of acetabular reorientation options. Wide capsulotomy and intra-articular procedures are possible, as well as additional femoral corrections. Childbirth via natural delivery is possible even after bilateral PAO9. Nerve injuries can be guarded against with careful surgical execution of the osteotomies4.

SENSITIVITY OF MODEL-PREDICTED MUSCLE FORCES OF PATIENTS WITH CEREBRAL PALSY TO VARIATIONS IN MUSCLE-TENDON PARAMETERS

Computational musculoskeletal modeling and simulation platforms are efficient tools to gain insight into the muscular coordination of patients with motor disabilities such as cerebral palsy (CP). Muscle force predictions from simulation programs are influenced by the architectural and contractile properties of muscle-tendon units. In this study, we aimed to evaluate the sensitivity of major lower limb muscle forces in patients with CP to changes in muscle-tendon parameters. Open-access datasets of children with CP ([Formula: see text]) and healthy children ([Formula: see text]) were considered. Monte Carlo analysis was executed to specify how sensitive the muscle forces to perturbations between [Formula: see text]% and [Formula: see text]% of the nominal value of the maximum isometric muscle force, optimal muscle fiber length, muscle pennation angle, tendon slack length, and maximum contraction velocity of muscle. The sensitivity analysis revealed that muscle forces of CP patients and healthy individuals were most sensitive to perturbations in the tendon slack length ([Formula: see text]), while forces of CP patients were more sensitive to tendon slack length when compared to the healthy group ([Formula: see text]). Muscle forces of patients and healthy individuals were insensitive to the other four parameters ([Formula: see text]), except for the gracilis and sartorius muscles in which the proportion of optimal muscle fiber length to tendon slack length is higher than 1; forces of these two muscles were also sensitive to the optimal muscle fiber length. The results of this study are expected to contribute to our understanding of which parameters should be personalized when conducting musculoskeletal modeling and simulation of patients with CP.

Rectus Femoris-based Muscle Pedicle Bone Graft for Osteonecrosis of Femoral Head: A New Surgical Technique

The pre-collapse and pre-degenerative stages of osteonecrosis of femoral head in young adults are preferably treated by a femoral head preservation operation with the objective to delay or possibly avert the further necrosis, collapse and degeneration of the hip joint. To salvage the early stages of the disease, several muscle pedicle bone grafting (MPBG) procedures based on Quadratus Femoris, Tensor Fasciae Latae, and Sartorius muscles have been described in the literature. To overcome the limitations of these procedures, the authors describe here a much simpler and safer MPBG based on the straight head of the Rectus Femoris with distal transposition of its origin along with anterior inferior iliac spineto the head-neck junction. To the best of our knowledge, MPBG based on Rectus Femoris has not been reported in the currently available literature on osteonecrosis of femoral head. Surgical technique with emphasis on protection of the posterior retinacular vessels, post-operative care and expected outcome is presented.

New approaches in surgery for osteomyelitis of the femoral neck and head via anterior access

To analyze an effectiveness of anterior approach to the hip joint for sequestrectomy with myoplasty. We have developed anterior surgical access for osteomyelitis of the femoral neck and head. Semi-oval incision is made in projection of the femoral head. Tendons of sartorius muscle and rectus femoris muscle are cut off from anterior spine of the iliac wing. Surgical field ensures sequestrectomy for osteomyelitis of the hip joint. Closure of osteomyelitis cavity is performed by the proximal parts of two anterior iliacus muscles. Surgical field may be enlarged by temporary intersection of iliopsoas muscle tendon. The key to anterior surgical approach to the hip joint is sartorius muscle and rectus femoris muscle. The length of surgical wound reaches 17-22 cm, width - 16-18 cm. The mobilized proximal part of sartorius muscle is used for closure of the entire bone cavity in femoral neck and head. Stable long-term remission was observed in 11 (91.7±7.6%) out of 12 patients. Original surgical approach is less traumatic and ensured manipulations under an angle of about 90°. This access complements the advantages of the well-known anterior approaches and has no their disadvantages.

Hemiarthroplasty of the hip using the direct anterior approach.

ObjectiveMinimally invasive approach in total hip arthroplasty for the treatment of femoral neck fractures with a hemiarthroplasty.IndicationsFemoral neck fractures of patients without hip osteoarthritis where the acetabulum is still intact.ContraindicationsLesions and infections of the skin in the approach area; hip osteoarthritis; surgeon’s lack of experience with the technique.Surgical techniqueThe direct anterior approach (DAA) uses the Smith–Peterson interval between the tensor fasciae latae (TFL) and the rectus and sartorius muscle. After coagulation of the ascending branches of the femoral circumflex vessels, the capsule is opened. The remaining parts of the femoral neck are removed and osteotomized if necessary. The femoral head is removed with a cork screw. Then the shaft is supported by 2 sharp retractors at the greater trochanter from cranial, and the leg is externally rotated, hyperextended, and adducted. A TFL release can be performed which we also recommend. The femoral canal is opened step by step and extended with rasps which are introduced with the double curved broach handle. Cement and the final implant are introduced and after the trial reduction also the final head. The hip is reduced, the capsule adapted and the wound closed.Postoperative managementFor this approach, there are no approach specific recommendations. Postoperative treatment depends on whether the approach was extended with muscle releases and on the type of reconstruction performed. If the approach was limited to the minimally invasive direct anterior portal, quicker rehabilitation can be expected due to the reduced muscle damage. We prefer mobilization with full weight bearing as tolerated on the next day.

Salvage of Infected Prosthetic Grafts at the Groin or Thigh Using Muscle Flap Coverage.

Objectives: This study aimed to evaluate early- and long-term outcomes in patients who undergo muscle flap coverage (MFC) for prosthetic graft infections (PGIs) at the groin or thigh.Materials and Methods: We retrospectively retrieved and analyzed data on infected wound cures, recurrence, graft and limb salvage, and survival of patients who underwent MFC for PGI at the groin or thigh between 2000 and 2018.Results: There were eight patients in our cohort: six had groin PGIs and two had thigh PGIs. Moreover, of these patients, seven were treated from sartorius muscles and one from a gracilis muscle. The indicated wounds healed in all eight patients, but two patients died during hospitalization. Three patients suffered recurrence within 8 months, one of which overcame the infection and achieved wound cure without graft removal, with negative pressure wound therapy. No patients lost their limbs during the follow-up term (mean, 24 months; range, 1–60 months). Finally, four patients (50%) survived without removal of the infected graft for longer than 2 years.Conclusion: MFC can be a curative treatment for PGI, but there remains a possibility of a recurring infection thereafter.

Function test of the activity and interrelations of lower extremity muscles of football players with the use of surface electromyography method

Efficient performance of physical activity is becoming a vital trend in modern football, which requires maximum objectification of the functional state of muscles. Aim: studying the electrical activity and functional relationships of sartorius and crurae muscles involved in phase movements of walking (running) by the method of multichannel registration of surface electromyogram (SEMG). Materials and methods: the study engaged the students of KSMU attending the football section and participating in football matches (n = 12). The electrical activity (EA) of the muscles involved in the implementation of walking (running): biceps femoris, musculus semimembranosus of the thigh and tibilais anterior muscle was registered. EA research was conducted with maximum volitional muscle tension. The recording was conducted using an 8-channel electroneuromyograph Neuro-MVP-8 prior to the football training and 30-60 minutes after. The data obtained were checked using Shapiro - Wilk tests. Ansari-Bradley test was used for small groups. Lastly, Kendall correlation coefficient was calculated to evaluate the functional relationships between the parameters of muscle EA. Results : The most significant changes in EA parameters after training consisted in their correlation. The presence of medium negative correlations between musculus semimembranosus of the thigh on right and left (r = -0.349) and the absence of correlation between the latter in the amplitude of EA were registered. Concurrently, positive correlations were noted between the EA parameters of the biceps femoris and semimembranosus (values ram.= 0,204, rfreq.= 0,226), as well as biceps femoris and tibilais (values ram.= 0,486, rfreq.= 0,452) of the left feet of football players. Conclusion: SEMG allows you to quantify the changes in electrical activity and functional connection of the muscles of the thigh and crurae involved in stepping and running. A realignment of the functional muscle complexes appears, which contributes to motor actions and implementation of dribbling after a training.

Rhinosporidiosis with musculoskeletal manifestation: A case series

Rhinosporidiosis is a chronic granulomatous disease caused by Rhinosporidium seeberi. It commonly affects young males and involves the mucous membranes of the nose, nasopharynx and eyes. Involvement of extranasal sites including bone has been rarely reported. Involvement of bone without associated mucocutaneous lesions is extremely rare in rhinosporidiosis. We report a case series of three rare cases of Rhinosporidiosis affecting the musculoskeletal system, involving the clavicle, distal interphalangeal joint of little finger, and lower limb Sartorius muscle. Keywords: Rhinosporidiosis, Phalanx, Distal interphangeal joint, Clavicle, Sartorious, Soft tissue.

Femoral nerve decompression and sartorius-to-quadriceps nerve transfers for partial femoral nerve injury: a cadaveric study and early case series.

Partial femoral nerve injuries cause significant disability with ambulation. Due to their more proximal and superficial location, sartorius branches are often spared in femoral nerve injuries. In this article, the authors report the benefits of femoral nerve decompression, demonstrate the feasibility of sartorius-to-quadriceps nerve transfers in a cadaveric study, describe the surgical technique, and report clinical results. Four fresh-frozen cadaveric lower limbs were dissected for anatomical analysis of the sartorius nerve. In addition, a retrospective review of patients with partial femoral nerve injuries treated with femoral nerve decompression and sartorius-to-quadriceps nerve transfers was conducted. Pre- and postoperative knee extension Medical Research Council (MRC) grades and pain scores (visual analog scale) were collected. Up to 6 superficial femoral branches innervate the sartorius muscle just distal to the inguinal ligament. Each branch yielded an average of 672 nerve fibers (range 99-1850). Six patients underwent femoral nerve decompression and sartorius-to-quadriceps nerve transfers. Four patients also had concomitant obturator-to-quadriceps nerve transfers. At final follow-up (average 13.4 months), all patients achieved MRC grade 4-/5 or greater knee extension. The average preoperative pain score was 5.2, which decreased to 2.2 postoperatively (p = 0.03). Femoral nerve decompression and nerve transfer using sartorius branches are a viable tool for restoring function in partial femoral nerve injuries. Sartorius branches serve as ideal donors in quadriceps nerve transfers because they are expendable, are close to their recipients, and have an adequate supply of nerve fibers.

Evaluation of sartorius muscle flap versus tensor fascia lata to cover exposed groin vascular grafts: which is better?

Purpose To focus on the importance of tensor fascia lata or sartorius muscle flaps to improve wound healing and to save exposed groin vascular grafts with minimal complications and to evaluate which is better. Background Treatment of an exposed groin vascular grafts after vascular interventions may be challenging. Saving these grafts saves a patient’s limb. Patients and methods A prospective, randomized clinical trial was conducted on 54 patients suffering from exposed groin vascular grafts to compare postoperative outcomes using tensor fascia lata flap [group A; 28 (51.8%) cases] versus sartorius muscle flap [group B; 26 (48.2%) cases]. Postoperative follow-up was for 6 months. Results No flap loss was recorded in any of the procedure. Minor complications, such as skin graft was lost partially, were seen in group A in five (17.9%) cases at the donor area, but partial loss of skin graft was noticed only in one (3.8%) case in group B (P=0.0022). Small hematoma was noticed in in six (21.4%) cases in group A but only in two (7.6%) cases in group B (P=0.0036). Finally, overall wound healing was noticed in 22 (78.6%) cases in group A and 24 (92.3%) cases in group B (P=0.014). Conclusion Both tensor fascia lata and sartorius muscle flaps for exposed groin vascular grafts are considered a protective weapon to save these exposed grafts and to help to ensure good wound healing. Sartorius muscle flaps are easily rotated from the same incision, are more effective, and are safe, with minimal postoperative complications.

Intraoperative two-stage evaluation of muscle contractures in Crowe type IV hips in total hip arthroplasty (a new surgical technique).

It is important to maintain soft-tissue balance and prevent muscle contractures after hip reduction during total hip arthroplasty (THA) in patients with Crowe type IV developmental dysplasia of the hip (DDH). To make such hips functional and durable, the techniques to achieve soft-tissue balance were studied to create an algorithm for intraoperative 2-stage evaluation of muscle contractures, specifying the optimal order for contracture release. Between February 2011 and March 2015, we evaluated 64 patients (75 hips) with DDH for muscle contractures as they underwent THA. Following acetabular implantation, femoral osteotomy was applied of various lengths according to limb-length discrepancy. First, the distal part of the femur was prepared by broaching, and the hip was then reduced. The tensor fascia lata, rectus femoris, sartorius, hamstrings, and adductor muscles were evaluated, and any contractures were released. A trial conjoining of the distal and proximal parts of the femur was made, and the hip was reduced again. Finally, the iliopsoas and abductor muscles were evaluated, and contractures were released. The mean follow-up duration was 4.6 years. Preoperative and postoperative Harris Hip Scores were 52 and 87, respectively. Limb-length discrepancy was mean 4.2 cm preoperatively, and <1 cm postoperatively. All contractures were released according to our newly developed algorithm. It is challenging to pinpoint the main muscle causing contractures, because other muscles acting on the hip joint have similar secondary functions. The method we describe here may provide better and more specific restoration of muscle function in a hypoplastic hemipelvis in DDH.

Positive Effects of Preventive Nutrition Supplement on Anticancer Radiotherapy in Lung Cancer Bearing Mice.

Simple SummaryThe supplement of TNuF, a total nutrition formula, before cancer diagnosis significantly enhanced the anticancer effect of radiotherapy against primary tumor and lung metastasis in tumor-bearing mice. Meanwhile, TNuF improved cancer related sarcopenia. We supposed that these benefits are related to the regulations of cell proliferation, angiogenesis, and immunity in tumor microenvironment.(1) Background: Radiotherapy (RT) is one of the major treatments for non-small cell lung cancer, but RT-associated toxicities usually impede its anticancer effect. Nutrient supplementation has been applied for cancer prevention or a complementary measure to anticancer therapy. Here, we explored the influence of total nutrition supplementation before and after cancer occurrence on the anticancer benefit and side effects of RT. (2) Methods: C57BL/6JNarl mice were inoculated with Lewis lung carcinoma cells and then treated with radiotherapy. TNuF, a total nutrition formula, was prescribed by oral gavage. In the preventive groups, TNuF supplementation started from seven days before tumor inoculation. In the complementary groups, TNuF supplementation began after tumor inoculation. (3) Results: TNuF successfully enhanced the anticancer effect of RT against primary tumor and lung metastasis. Additionally, the complementary supplement improved the high serum TNF-α level and the wasting of sartorius muscle in mice receiving RT. In histologic and molecular analysis, TNuF was observed to modulate EGFR, apoptosis, and VEGF and PD-1/PD-L1 pathways. Furthermore, the anticancer benefit of the preventive supplement was comparable to that of the complementary administration. (4) Conclusions: Our results demonstrated that the prescription of the TNuF total nutrition formula before and after cancer diagnosis attains similar benefits in testing subjects with typical anticancer RT. TNuF is also a potential sensitizer to anti-PD-1 immune therapy.

The use of vascularised muscle flaps for treatment or prevention of wound complications following arterial surgery in the groin.

Wound complications following arterial surgery in the groin are relatively common and can result in significant morbidity and mortality. Vascularised muscle flaps (VMF) may be used as an adjunct to aid healing, either to manage complications or prophylactically. This series describes 46 patients who received sartorius or gracilis muscle flaps, of which 70% were performed as a salvage procedure to treat complications ranging from wound breakdown to vascular graft infection. The remaining 30% were performed at the time of the arterial surgery in patients with risk factors such as re‐do surgery or immunosuppression. The peri‐operative mortality rate was 9% and the major amputation rate was 26%, reflecting the complexity of patients that require intervention. Overall, 85% achieved successful healing in the groin without the need for further treatment following VMF. Only one case of flap necrosis occurred. Wound healing complications occurred more commonly after sartorius muscle flaps. The gracilis muscle offers a bulkier mass and greater mobility and so may be preferable, particularly for larger groin defects. This series has shown that VMF offer a safe and reliable option for selected cases to achieve wound healing in the groin in patients with often significant co‐morbidities.

Use of Muscle Feeding Arteries as Recipient Vessels for Soft Tissue Reconstruction in Lower Extremities.

Microsurgical free tissue transfer is still playing an important role in lower extremity reconstruction. Finding a suitable recipient artery for anastomosis is critical in the microsurgical procedure, especially in an extensive wound, or in a complex trauma combined with vascular injury. From April 2014 to March 2018, we retrospectively reviewed patients with traumatic/post-traumatic, oncologic, and electrical wounds in the lower extremity. Those treated with muscle feeding artery as recipient vessels were included. The latissimus dorsi (LD) muscle free flap, anterior lateral thigh (ALT) perforator free flap, and deep inferior epigastric perforator (DIEP) free flap were raised. The muscle feeding arteries to vastus lateral muscle and to medial head of gastrocnemius muscle, concomitant veins, and great saphenous vein were used as recipient vessels. Injuries included in the study were caused by tumour in 2 cases, car accident in 3 cases, crushing in 3 cases, burns in one case, and electrical injury in one case. The wound size varied from 14 cm × 6 cm to 30 cm × 20 cm. LD, ALT, and DIEP free flaps were used in 6, 3, and 4 patients, respectively. The muscle feeding arteries to medial head of gastrocnemius muscle, to sartorius muscle, and to vastus lateral muscle were used as recipient arteries in 4, 5, and one patient, respectively. Concomitant and great saphenous veins were used as recipient veins in 10 and 4 patients, respectively. Using the muscle feeding artery is feasible to avoid injury to the main artery and facilitate dissection and anastomoses, particularly when the wound is located proximal to the mid-third of the lower leg.

MiRNA\u2013mRNA network regulation in the skeletal muscle fiber phenotype of chickens revealed by integrated analysis of miRNAome and transcriptome

Skeletal muscle fibers are primarily categorized into oxidative and glycolytic fibers, and the ratios of different myofiber types are important factors in determining livestock meat quality. However, the molecular mechanism for determining muscle fiber types in chickens was hardly understood. In this study, we used RNA sequencing to systematically compare mRNA and microRNA transcriptomes of the oxidative muscle sartorius (SART) and glycolytic muscle pectoralis major (PMM) of Chinese Qingyuan partridge chickens. Among the 44,705 identified mRNAs in the two types of muscles, 3,457 exhibited significantly different expression patterns, including 2,364 up-regulated and 1,093 down-regulated mRNAs in the SART. A total of 698 chicken miRNAs were identified, including 189 novel miRNAs, among which 67 differentially expressed miRNAs containing 42 up-regulated and 25 down-regulated miRNAs in the SART were identified. Furthermore, function enrichment showed that the differentially expressed mRNAs and miRNAs were involved in energy metabolism, muscle contraction, and calcium, peroxisome proliferator-activated receptor (PPAR), insulin and adipocytokine signaling. Using miRNA-mRNA integrated analysis, we identified several candidate miRNA-gene pairs that might affect muscle fiber performance, viz, gga-miR-499-5p/SOX6 and gga-miR-196-5p/CALM1, which were supported by target validation using the dual-luciferase reporter system. This study revealed a mass of candidate genes and miRNAs involved in muscle fiber type determination, which might help understand the molecular mechanism underlying meat quality traits in chickens.

Acetabular reaming and sartorius muscle pedicle iliac bone grafting in the treatment of developmental dysplasia of the hip in older children: a retrospective study of 15 patients with more than two years follow-up.

PurposeDespite the early diagnosis and treatment of developmental dysplasia of the hip (DDH), some older children still need open reduction. It is usually difficult to get a satisfactory reduction particularly in patients with acetabular defect. The purpose of this study was to evaluate the short-term outcomes of acetabulum reaming and sartorius muscle pedicle iliac bone grafting in the treatment of older children with DDH and acetabular defect.MethodsThe records of 15 patients with DDH (mean age 113.9 months (sd 29); 17 hips) who were treated with the reported technique between February 2015 and January 2017 were retrospectively reviewed. All patients acquired regular clinical and radiographic follow-ups, and alterations in the acetabular index, centre-edge angle and acetabular head index were measured. Joint function and radiographic results were evaluated with McKay and Severin modified criteria, respectively.ResultsA total of 15 patients were followed up for mean 32.4 months (sd 6.9). The percentages of excellent and good conditions were 94.1% (16/17) according to the Severin modified criteria and 88.2% (15/17) according to the McKay modified criteria. Avascular necrosis of the femoral head and redislocation only occurred in one hip. No cases of ankylosis or bone graft absorption occurred during the follow-up.ConclusionReaming the acetabulum and sartorius muscle pedicle iliac bone grafting for repairing the acetabular defect can recover the arcuate structure by increasing the volume of the acetabulum, which is beneficial for achieving a concentric reduction. The short-term outcome was satisfactory, while the long-term results need to be further observed.Level of EvidenceIV – retrospective study

Anatomical description of the origin and distribution of the lumbosacral plexus in one puma (Puma concolor)

Wild felids often suffer spinal and limb disorders; however, their nervous system anatomy is poorly studied. Herein, the lumbosacral plexus (Plexus lumbosacralis) of an adult puma and the motor and sensitive innervation of the pelvic limb is described. We found anatomical similarities to other felids, but also some differences. Branches L4-S3 form the lumbosacral plexus (Plexus lumbosacralis) in the puma. The femoral nerve (N.femoris) arises from the union of L4-L5, while in other felids, it is formed by L5-L6. Unlike in the cat, the sartorius muscle receives branches from the saphenous (N.saphenous) and femoral nerves (N.femoris), and the lateral head of the gastrocnemius and superficial digital flexor muscles are innervated by a branch of the soleus muscle.

Heat stress-induced deficits in growth, metabolic efficiency, and cardiovascular function coincided with chronic systemic inflammation and hypercatecholaminemia in ractopamine-supplemented feedlot lambs.

Heat stress hinders growth and well-being in livestock, an effect that is perhaps exacerbated by the β1 agonist ractopamine. Heat stress deficits are mediated in part by reduced feed intake, but other mechanisms involved are less understood. Our objective was to determine the direct impact of heat stress on growth and well-being in ractopamine-supplemented feedlot lambs. Commercial wethers were fed under heat stress (40 °C) for 30 d, and controls (18 °C) were pair-fed. In a 2 × 2 factorial, lambs were also given a daily gavage of 0 or 60 mg ractopamine. Growth, metabolic, cardiovascular, and stress indicators were assessed throughout the study. At necropsy, 9th to 12th rib sections (four-rib), internal organs, and feet were assessed, and sartorius muscles were collected for ex vivo glucose metabolic studies. Heat stress increased (P < 0.05) rectal temperatures and respiration rates throughout the study and reduced (P < 0.05) weight gain and feed efficiency over the first week, ultrasonic loin-eye area and loin depth near the end of the study, and four-rib weight at necropsy. Fat content of the four-rib and loin were also reduced (P < 0.05) by heat stress. Ractopamine increased (P < 0.05) loin weight and fat content and partially moderated the impact of heat stress on rectal temperature and four-rib weight. Heat stress reduced (P < 0.05) spleen weight, increased (P < 0.05) adrenal and lung weights, and was associated with hoof wall overgrowth but not organ lesions. Ractopamine did not affect any measured indicators of well-being. Heat stress reduced (P < 0.05) blood urea nitrogen and increased (P < 0.05) circulating monocytes, granulocytes, and total white blood cells as well as epinephrine, TNFα, cholesterol, and triglycerides. Cortisol and insulin were not affected. Heat stress reduced (P < 0.05) blood pressure and heart rates in all lambs and increased (P < 0.05) left ventricular wall thickness in unsupplemented but not ractopamine-supplemented lambs. No cardiac arrhythmias were observed. Muscle glucose uptake did not differ among groups, but insulin-stimulated glucose oxidation was reduced (P < 0.05) in muscle from heat-stressed lambs. These findings demonstrate that heat stress impairs growth, metabolism, and well-being even when the impact of feed intake is eliminated by pair-feeding and that systemic inflammation and hypercatecholaminemia likely contribute to these deficits. Moreover, ractopamine improved muscle growth indicators without worsening the effects of heat stress.

Anatomical Characterization of the Inguinal Lymph Nodes Using Micro‐Computed Tomography to Inform Radical Inguinal Lymph Node Dissections for Metastatic Penile Cancer

Background, Rationale &amp; AimIn men with penile cancer, a radical inguinal lymph node dissection (rILND) is integral to prevent metastasis and improve disease specific survival. Unfortunately, lymphocele and lymphedema are severe post‐surgical complications that are common to this procedure. The development of a modified inguinal lymph node dissection, that greatly reduced the amount of lymphatic resection, was effective at reducing the incidence of lymphedema and lymphocele; however, it was not suited for patients with advanced‐stage disease as it risked an incomplete cancer resection. As such, there exists a clinical need for a novel surgical template ‐ informed by the lymphatic anatomy ‐ to reduce these post‐surgical complications while ensuring a thorough cancer resection. However, the lymphatic anatomy of the inguinal region is not well characterized in the literature, with no definitive location or number of lymph nodes reported. Therefore, this study aims to elucidate the lymphatic anatomy within the current surgical borders of a rILND using human cadavers.MethodologyTo visualize the position of the lymph nodes, tissue packets excised from the inguinal region were imaged using micro‐computed tomography (μCT; 154 μm Locus Ultra CT scanner). To characterize the distribution of lymph nodes within each tissue packet, lymph nodes were segmented by grayscale values in 3D using a modified seed‐growing algorithm (Region Growing v1.5; Kellner, 2011) in MATLAB. To compare anatomy between tissue packets, the segmented lymph nodes were aligned (registered) with one another by translating, scaling, rotating, and mirroring (if necessary) such that they were all superimposed in a common coordinate system. This was achieved using a specimen‐specific transformation matrix that was obtained from a generalized Procrustes analysis performed using the positions of four landmarks from each specimen; the anterior superior iliac spine, pubic tubercle, sapheno‐femoral junction, and sartorius as it crosses the femoral artery. These landmarks were chosen due to their consistency between individuals as well as their use as surgical landmarks.ResultsPreliminary findings from five samples (n=3 cadavers) show a median of 6 lymph nodes (range = 3–7); their anatomical distribution is illustrated in Figure 1. In addition to obtaining more specimens, ongoing work focuses on segmentation of structures in this region, such as saphenous vein and the sartorius muscle, to provide spatial context to the identified lymph node distribution.Significance &amp; ImplicationsThis study provides the first standardized comparison of lymph node anatomy in the inguinal region, and utilizes a novel imaging methodology validated by our lab to study the anatomy of lymphatic tissue in 3D and in situ. In doing so, the anatomy elucidated in this study will help inform refinement to the borders of the radical surgical template, to limit unnecessary resection in an attempt to reduce the incidence of post‐surgical lymphedema and/or lymphocele.The standardized lymph node data after having the generalized Procrustes analysis applied. The dotted lines represent the rILND surgical borders.Figure 1

The Impact of Leg Length on the Path of the Infrapatellar Branch of the Saphenous Nerve

ObjectiveIatrogenic injury to the infrapatellar branch of the saphenous nerve (IPBSN) is a common sequela of anteromedial incisions during knee procedures. To more accurately predict a “safe‐zone” for incisions, we investigated the correlation between the path of the nerve and the length of the leg. The origin of the IPBSN relative to the sartorius muscle (SM) was identified to compare to previous studies.Methods103 knees from 53 formalin preserved cadavers were dissected at Kansas City University of Medicine and Biosciences, Creighton University, and the University of Nebraska Medical Center. The IPBSN was located as it approached the medial aspect of the patellar ligament. The location was documented by measuring from the intersection of the patella with the medial (Point A) and lateral (Point B) borders of the patellar ligament at angles from 0°, 30°, 45°, 60° and 90° from horizontal. Leg length was determined by the distance from the tibial plateau at the intersection of the medial collateral ligament to the distal aspect of the medial malleolus. The nerve was exposed proximally to identify its origin relative to the SM.ResultsFrom Point A, at angles from 0°, 30°, 45°, 60° and 90° from horizontal, we calculated the mean minimum and mean maximum distances to the nerve. These measurements allowed the investigators to identify a “danger zone” for expected injury to the IPBSN.No correlation existed between leg length and the mean minimum distance to the nerve. However, length had a significant, but low degree of correlation to the mean maximum distance to the IPBSN that increased as the nerve approached its most distal reaches. At angles of 45°, 60°, and 90° from Point A as well as 90° from Point B, the distance to the IPBSN increased as leg length increased.We also identified variations not previously reported. In some individuals, we identified multiple nerves serving the infrapatellar area. Many had innervation originating directly from the femoral nerve in the femoral triangle. Further, the emergence of the IPBSN relative to SM differed from previous studies, with the majority of individuals having at least one nerve penetrating through rather than emerging posterior to the SM.ConclusionWe defined safe areas for incisions as −1 SD from the mean minimum distance and +1 SD from the mean maximum distance from point A. Given there was no correlation between leg length and the minimum mean distance from point A, the safe‐zone superior to the nerve is unaffected by the length of the leg. While there was a correlation between leg length and the maximum mean distance from point A at 45°, 60°, and 90°, those are outside the area of possible incisions. Therefore, the safe‐zone inferior to the nerve is also unaffected. Existing literature has not identified infrapatellar branches arising directly from the femoral nerve. Individuals with this variation would not respond well to saphenous nerve blocks, requiring a more proximal, femoral nerve block that would temporarily compromise motor function of the anterior thigh.