This might help surgeons visualize over the possibility of the existence of any such variation while performing any surgical procedure in the posterior maxillary area. In order to establish the embryological basis of these findings, investigation on a larger number of specimens is highly suggested by the authors.

Basic sciences are a cornerstone of undergraduate medical education (UME), yet research indicates that students’ basic science knowledge is not well retained. Many UME curricula are increasing the integration between the basic and clinical sciences with the goal of enhancing students’ knowledge levels; however, the impact of clerkship training on students’ basic science knowledge remains inconclusive. Thus, using clerkship directors’ expectations as framework, we aimed to assess third-year medical students’ basic science knowledge during clerkship training and evaluate the influence of clerkship training on their basic science knowledge. Using concepts deemed necessary by clerkship directors, we created a basic science assessment for each clerkship rotation. Assessments were distributed to third-year medical students as a pre- and post-test to assess their basic science knowledge prior to and at the completion of each rotation. On average, students retained ≥ 60% of relevant basic science knowledge from pre-clerkship, and neither clerkship rotation order, nor the basic science discipline being assessed, impacted students’ basic science knowledge levels. Post-test data revealed that students, on average, reinforced fundamental concepts during clerkship. Interestingly, even though lower-performing students demonstrated the greatest post-test improvement, they still left each rotation with knowledge deficits compared with their highest-performing peers, suggesting that the clinical experience of clerkship appears to be particularly beneficial for lower-performing students, in regard to enhancing their basic science knowledge. Overall, results indicate that earlier exposure to clinical learning in UME, along with integration of basic science education into clerkship, could promote students’ basic science knowledge acquisition and retention.

Basic sciences are a cornerstone of undergraduate medical education (UME) as they provide a necessary foundation for the clinical sciences to be built upon and help foster trainees' competency. However, research indicates that students' basic science knowledge is not well retained, and as a result, students are ill-prepared, with respect to their basic science knowledge, when entering clerkship. One potential reason why students may not be prepared for clerkship is a lack of understanding as to which basic science concepts are critical for medical students to retain from pre-clerkship. We facilitated interviews with all core UME clerkship directors to establish which basic science concepts they expect students to know prior to each clerkship rotation, along with student's basic science strengths and areas of improvement. Interviews revealed that students are expected to have some knowledge of every basic science prior to clerkship, with pharmacology being a strong focus, as many specialties deal with common drugs and classes of drugs. Additionally, general anatomy and physiology knowledge were deemed student strengths in two rotations. Clerkship directors focused on perceived areas of improvement more than perceived strengths, with the most prevalent areas being pharmacology, microbiology, and detailed anatomy. These results represent views of clerkship directors from one Canadian institution; however, since clerks rotate through institutions across Canada, this data provides the impetus for creating a national discussion to help foster standardization of UME curricula, with the overarching goal of ensuring all graduates are proficient in the necessary fundamentals as they transition into residency.

Background: Lateral approaches to total knee arthroplasty (TKA) provide good surgical exposure and may provide greater ease of soft tissue balancing in patients with a valgus deformity: however, little is known about the versatility in non-valgus knees. The present study evaluated if a lateral subvastus approach can achieve adequate surgical exposure while maintaining less soft tissue damage compared with the medial parapatellar approach in knees without any significant deformity. Methods: Using paired fresh-frozen cadaveric knees, the present study provides the first specimen-matched, side-by-side comparison of the lateral subvastus approach to the standard medial parapatellar approach to TKA. Ten knees were selected to undergo a lateral subvastus approach; the contralateral knee had a medial parapatellar approach as control. Incision length, surgical exposure and iatrogenic soft tissue damage were compared between the two approaches. Results: The lateral subvastus approach was successfully performed using an incision length that was not different from that used in the medial parapatellar approach (p > 0.05). The resultant surgical exposure was comparable between approaches (p > 0.05). The risk of the approach included tearing of the vastus lateralis fibers, and/or abrasion of the iliotibial tract/patellar ligament. Conclusions: The lateral subvastus approach to TKA provided a comparable method to the standard medial parapatellar approach. Despite adequate exposure, the approach did risk soft tissue injury. Caution needs to be exercised to reduce the risk of iatrogenic injury to the vastus lateralis and surrounding ligaments. The successful implementation in this cadaveric study substantiates the need for further consideration of this approach in clinical practice. (C) 2020 Elsevier B.V. All rights reserved.

Objective The purpose of this study is to determine if removal of ethmoid cell septations as commonly performed in endoscopic sinus surgery leads to a change in orbital wall fracture patterns and the force required to create them. Methods Six fresh-frozen cadaveric heads were acquired and underwent endoscopic uncinectomy, maxillary antrostomy, and anterior and posterior ethmoidectomy on one, randomized, side. The contralateral sinuses were used as intra-specimen control. Hyaluronic acid gel globe injections were performed to simulate normal intra-ocular pressure. Post-op CT scans confirmed no orbital fractures or violation of the lamina papyracea prior to trauma testing. Orbital trauma was induced using a guided weight-drop technique. Both orbits were tested in random order, and sequentially higher drops were performed until both the test and control side demonstrated an orbital fracture on CT scan. Results In all six heads, the post-sinus surgery side incurred a medial orbital wall fracture, and no orbital floor fractures were identified. On the other hand, on the control side, all six heads incurred orbital floor fractures at drop heights equal to, or higher than, the surgical side. Fisher's exact test demonstrated a significant difference in fracture pattern ( p < 0.001). Conclusions To our knowledge, this is the first demonstration that the structures removed during sinus surgery may act as a buttress for the medial orbital wall. The anatomic changes of sinus surgery may alter the biomechanics of the orbit and affect the pattern of subsequent traumatic blowout fractures.

Dear editor We thank Dr Hongye and colleagues[1][1] for their interest in our cadaveric study.[2][2] It appears that we are all chasing the holy grail when it comes to preserving analgesic efficacy for shoulder surgery, while minimizing phrenic paresis. We agree that the injectate targeting the

Backgrounds and objectives The anterior approach to the subomohyoid suprascapular (SOS) nerve is a new, technically easy and reliable regional anesthesia technique for postoperative shoulder analgesia. However, due to its proximity, the injectate may spread to the brachial plexus and phrenic nerve. The goal of this anatomic study with dye injection in the subomohyoid space and subsequent cadaver dissection was to establish the likely spread of local anesthesia and the extent of brachial plexus and phrenic nerve involvement resulting from ultrasound-guided SOS nerve block. Methods The suprascapular nerve (SSN) under the inferior belly of omohyoid muscle in the posterior triangle of the neck was identified. Using a contrast dye, 10 ultrasound-guided SOS nerve injections of 5 mL were done bilaterally, in five fresh cadavers. The area was then dissected to evaluate the spread of the contrast dye in the immediate proximity of the brachial plexus, phrenic and SSN. Results The SSN and omohyoid muscle were easily identified on each cadaver. SOS nerve staining with contrast dye was seen in 90% of dissections. The superior trunk was stained in 90% and the middle trunk was stained in 80% of dissections. The inferior trunk was stained in 20% of dissections. A spread of dye around the SSN was observed in 90% and the phrenic nerve was mildly stained in 20% of the dissections. Conclusion In-plane ultrasound-guided needle injection with a 5 mL volume for SOS block was sufficient to stain the SSN. This conservative volume involved other parts of the brachial plexus and may potentially spread to the phrenic nerve. Further clinical studies are required for confirmation.

Background Nasolabial dermal filler (DF) injections are one of the most popular cosmetic procedures performed worldwide. DF injections at the nasolabial fold have been associated with nasal necrosis due to inadvertent intravascular injection of the adjacent facial artery (FA). Current DF injection protocols are devoid of imaging the anatomical site, and the use of ultrasound (US) for imaging the FA is very limited in literature. The purpose of this study is to determine the feasibility of utilizing US to identify and measure the FA at different bony landmarks near and within the nasolabial region. Methods Part I Cadaveric dissections (n=18; 10 female, 8 male) will be completed to explore the course of the FA from the external carotid artery to the terminal branches supplying facial structures. Part II A bilateral US of the FA using 13–6 MHz, 38 mm linear array US transducer was performed on consenting adults (n=16; 9 female, 7 male) from the Department of Anatomy and Cell Biology at Western University. The following bony landmarks were identified and used for US measurements, taken in real time: anterior‐inferior angle of the mandible, mandibular teeth, maxillary teeth, maxillary ridge. Measurements of FA diameter, artery distance to skin, and artery distance to bone were obtained at each landmark using digital image distance measurements on the Sonosite M‐Turbo P08189‐88R US machine. Results Part I Preliminary results (n=8; 4 female, 4 male) show FA variability between cadaveric specimens, as well as left/right FA variability within cadaveric specimens themselves. Part II Preliminary results of the average FA distance to the skin measured at 0.438 cm ± 0.126 for the left FA and 0.459 cm ± 0.205 for the right FA. A significant difference (P< 0.05) was noted for FA distance to the skin between the left mandibular teeth (0.481 cm ± 0.107) and left maxillary ridge (0.343 cm ± 0.097). Conclusions These findings highlight the importance of understanding the anatomy of the FA within the nasolabial fold, and the need to carefully personalize the placement of DF injections, due to the anatomical variability identified in both the cadaveric and ultrasound portions of the study. Furthermore, since it is feasible to identify and measure the FA using the selected US transducer, the future direction of this study will be to examine the application of US to guide DF injections. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

BackgroundTotal knee arthroplasty (TKA) has been a reliable method for effectively treating advanced knee arthropathy. A medial parapatellar approach (MPA) is commonly used because of its large exposure and versatility; however, iatrogenic soft tissue damage remains a concern. In response, several alternative approaches have emerged that aim to reduce soft tissue damage, though their clinical usefulness is often limited by poor surgical exposure of the internal compartments of the knee. Based on the relevant surgical anatomy of the knee, we propose the subvastus lateralis approach (SLA) as a novel alternative. The aim of the present study is to explore the anatomical and surgical advantages of using the SLA compared to the MPA for TKA.MethodsTo compare surgical effectiveness, a TKA was conducted on 22 paired fresh‐frozen cadaveric limbs (five females/six males) randomly assigned to either the SLA or MPA. All procedures were conducted by the same experienced surgeon. Primary parameters measured were the perimeter of surgical exposure as well as the length of skin incision. Additionally, subjective observations of the medial and lateral patellar contact were noted to assess patellar tracking. Afterwards, gross dissection of the limb was conducted to analyze any disruptions in the following soft tissues: components of the extensor mechanism, iliotibial band, tendon of the popliteus, and medial/lateral collateral ligaments.ResultsThe SLA provided adequate exposure to the internal compartments of the knee that was not statistically different to the mean exposure perimeter achieved using the MPA (p>0.05). Furthermore, the exposure provided by the SLA was achieved using a skin incision that was not statistically different compared to the MPA (p>0.05). In addition, patellar tracking showed superior results, where proper tracking was obtained in 100% of the SLA cases compared to 50% of those having undergone the MPA. Preliminary observations show that the SLA is successful in sparing the quadriceps tendon and the majority of the vastus lateralis. Conversely, in a subset of cases, the patellar ligament sustained a 0.1–0.7 mm transverse disruption of its distal fibers during the cutting of the tibial plateau.ConclusionThe SLA to TKA was able to be successfully completed in 100% of the specimens, with no major modifications to the technique. This approach proved to be reliable in knees with no notable deformities (valgus or varus) and provided an equal exposure to the internal compartments of the knee when compared to the standard MPA. It is important to note that this exposure was achieved using a skin incision of similar length to the MPA. The SLA also shows promising results regarding proper patellar tracking, though future investigation should be conducted to objectively assert these benefits. Finally, preliminary results show a reduction in the disruption of the quadriceps tendon and muscles when using the SLA, however, damage to the patellar ligament may occur. Future studies should evaluate the versatility of the SLA through an examination of specimens with a known degree of knee deformity.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Introduction The phrenic nerve (PN) is a bilateral peripheral nerve originating primarily from the anterior rami of C4 with varying contributions from C3 and C5. It courses inferiorly along the anterior scalene deep to the pre‐vertebral fascia, passes posterior to the first rib entering the thorax to innervate each hemi‐diaphragm, respectively. The PN is the only motor input to the diaphragm; its activation results in diaphragmatic contraction, facilitating inspiration, and breathing. Cervical hyper‐flexion/extension injury (CHFEI) is a common consequence of motor vehicle collisions (MVC). The extension moment may result in damage to the anterior scalene. Based on the path and anatomical location of the PN in the neck and the mechanism of CHFEIs there is potential for injury to the PN to occur during MVCs. Injury or damage to the PN can cause a range of dysfunctions including shortness of breath (SOB), altered breathing patterns (ABP), the inability to breathe independently, referred pain to C3‐5 dermatomes, and altered core control. However, to our knowledge, investigation of damage to the PN is not evaluated clinically following cervical trauma. This is a potential gap in the literature that needs to be investigated as PN injury may result in un‐ or misdiagnosed ABPs, SOB, and/or chronic pain in the C3‐5 dermatome region. This study aims to suggest potential sites of adhesion of the PN and propose treatment strategies based on its' anatomical path and determine the prevalence and implications of symptoms suggestive of PN injury secondary to CHFEI. Methodology Detailed dissection of the PN along its course in the anterior neck and thorax to its innervation of the diaphragm was completed on embalmed (n=9) and fresh/frozen (n=2) cadavers to examine potential sites where damage to the PN or adhesions of surrounding tissues would be more susceptible. Results In both embalmed and fresh/frozen cadavers the PN consistently courses along the anterior scalene either bound tightly between the anterior scalene and pre‐vertebral fascia or adhered directly to the pre‐vertebral fascia. It's consistently incorporated within the fascial sheath surrounding the subclavian artery/vein, and the mobility of the PN is minimal until the surrounding pre‐vertebral fascia and/or fascial sheath surrounding the sublacian artery/vein is removed. Discussion The limited mobility of the PN suggests that a CHFEI could result in a traction injury of the PN, which could cause ABP, SOB, and/or pain in the C3‐5 dermatome region. Injury to tissues surrounding the PN, especially the pre‐vertebral fascia, could cause adhesions and further limit mobility of the PN resulting in similar symptoms as those present with PN injury. To determine if PN injury is assessed clinically in patients that have sustained CHFEI a survey will be sent to clinicians. As well, a patient intake form will be created to determine the prevalence of symptoms present post CHFEI that could be related to PN injury. Future study will include measurements of PN mobility with cervical positions that would mimic those typically present in CHFEI's.

Although incidence is at epidemic levels, objective indicators of neurologic damage in adolescent concussion remain poorly described. Autonomic markers such as heart rate variability (HRV) have provided equivocal results; however, these predominantly are made under conditions of minimal physiologic stress. The current investigation employs postural stressors to examine underlying neurological outcomes associated with acute concussion and clinical recovery to test the hypothesis that concussion impairs dynamic autonomic adjustments in adolescents. We examined concussed adolescents (CONC; n = 35; 14 males; age 15 ± 1 yrs, range = 12–18 yrs) for up to 6 weekly visits from diagnosis. A group of age and activity level‐matched non‐concussed adolescents (CTRL; n = 35; 19 males; age 14 ± 2 yrs, range = 12–18 yrs) formed the reference control. HRV (root mean square of successive differences in R‐R intervals (RMSSD)) and heart rate were assessed during a sit‐to‐stand protocol (two trials of seated posture (three minutes), followed by two minutes of standing). Measurements were taken during the last minute of sitting and standing, the ten second period following the postural stress of standing, as well as the ten second period from maximum HR. While seated, RMSSD was lower in CONC (41 ± 24 msec) compared with CTRL (60 ± 40 msec; p < 0.05). 31 patients provided weekly data until clinical discharge. Compared with the first visit (43 ± 25 msec), seated RMSSD in CONC increased (51 ± 36 msec; p = 0.05) at the time of clinical discharge. Upon standing (10 seconds following postural change to standing), RMSSD was lower in CONC versus CTRL (13 ± 7 vs. 18 ± 12 msec; p < 0.05). Compared with the first visit, RMSSD following the induced postural stress did not improve in CONC over the six week recovery period. Following maximal HR, CTRL had increased RMSSD versus CONC (46 ± 30 vs. 34 ± 19 msec; p < 0.05). Compared with CTRL, seated HR was higher in CONC. This tachycardia effect persisted throughout the sit‐to‐stand protocol (78 ± 12 vs. 72 ± 12 bpm; p < 0.05) and was maintained until the time of clinical discharge (79 ± 13 vs. 72 ± 12 bpm; p < 0.05). In adolescent concussion, autonomic cardiac impairment is demonstrated by reduced RMSSD in the seated position and throughout the adjustment period in response to postural stress. Further, seated HR is increased following acute concussion and remains elevated by the time of clinical discharge. Seated HRV, but not HR, recovered to levels seen in the control population within three to six weeks. Thus, cardiac adjustments to modest postural stress may represent a measurable neurological impairment in adolescent acute concussion which can be objectively monitored throughout clinical recovery.Support or Funding InformationResearch supported by the Children's Health Research Institute (London, Canada).

Background The anterior iliac crest (AIC) is one of the most common sites for harvesting autologous bone, but the associated postoperative pain can result in significant morbidity. Recently, the transmuscular quadratus lumborum block (TQL) has been described to anesthetize the thoraco-lumbar nerves. This study utilizes a combination of cadaveric models and clinical case studies to evaluate the dermatomal coverage and analgesic utility of TQL for AIC bone graft donor site analgesia. Methods Ten ultrasound-guided TQL injections were performed in five cadaver specimens using a lateral-to-medial transmuscular approach. Twenty mL of 0.5% methylcellulose was injected on each side after ultrasound confirmation of the needle tip ventral to the quadratus lumborum muscle (QLM). Cranio-caudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy and direct staining of the thoraco-lumbar nerves were recorded. Following the anatomical findings, continuous catheter TQL blocks were performed in four patients undergoing ankle surgery with autologous AIC bone graft. The dermatomal anesthesia and postoperative analgesic consumption were recorded. Results In the anatomical component of the study, 9/10 specimens showed a lateral spread anterior to the transversalis fascia and medially between the QLM and psoas major muscle. Direct staining of the branches of the T12, L1, and L2 nerves was noted ventral to the QLM, while variable staining of the T9-T11 nerves was seen laterally in the transversus abdominis plane and the transversalis fascia. The vertical spread of injectate anterior to the QLM was T12 to the iliac crest ( n = 5/10) and L1 to the iliac crest ( n = 4/10). In the four patients who received TQL, the T9-L2 dermatomal anesthesia correlated with the injectate spread seen in the cadavers and provided effective analgesia at the bone graft donor site. Conclusion Ultrasound-guided TQL injections consistently cover the thoraco-lumbar innervation relevant to the AIC graft donor site. The injectate spread seen in anatomical dissections correlated with the dermatomal anesthesia clinically. The TQL has the potential to provide reliable analgesia for patients undergoing AIC bone graft harvesting.

INTRODUCTION The sympathetic nerves and ganglia overlying the abdominal aorta in humans are symmetrically organized into a bilateral network called the aortic plexus that must be spared during retroperitoneal surgery in order to maintain antegrade ejaculation. It is well established that complete resection of the aortic plexus causes retrograde ejaculation (RE) that results from de‐innervation of the internal urethral sphincter (IUS). At present, however, it remains uncertain which specific nerves of the aortic plexus control the IUS, and thus, which nerves are important for ejaculation. To ultimately determine which nerves are imperative to maintain ejaculation, the present study aimed to first establish the pig as a comparable model of the human aortic plexus in both structure and function. It was our working hypothesis that the pig exhibits comparable anatomy in terms of gross organization, number of infrarenal splanchnic nerves and constituent ganglia, and that stimulation of the left and right hypogastric nerves (homologous to the human superior hypogastric plexus) would evoke contraction of the IUS. METHODS The porcine aortic plexus was examined in 18 boars by gross dissection followed by a histological examination to differentiate ganglia from nerve. Innervation of the IUS was examined using a lesion‐and‐test method, in which stimulation with a bipolar electrode was used to excite the hypogastric nerves distal to the caudal mesenteric ganglia before and after transection (n=5). RESULTS As predicted, the anatomy of the porcine aortic plexus appeared comparable to humans, exhibiting two bilateral cords that were supplied by two or more infrarenal lumbar splanchnic nerves. Right and left caudal mesenteric and spermatic ganglia were invariably observed adjacent to their respective arteries, and given their topography within the plexus, they appear homologous to the prehypogastric, inferior mesenteric and spermatic ganglia in humans, respectively. At the junction of the upper infrarenal lumbar splanchnic nerves, two additional ganglia were observed within the cords of the porcine aortic plexus (prevalence right = 4/8; prevalence left = 3/8); these structures have not been reported in humans. Electrostimulation of each hypogastric nerve evoked bladder neck contraction (ΔP right = 6.2 ± 2.2 mmHg, ΔP left = 4.5 ± 2.2 mmHg), which was abolished following transection. CONCLUSIONS Collectively, our results confirm that the pig represents an effective preclinical model for studying not only the structure and normal function of the aortic plexus, but also the implications of unintended surgical trauma on the delicate nerves controlling ejaculation. Support or Funding Information This work is supported by CIHR

Introduction Within the past decade, competency‐based medical education (CBME) has acquired a lot of attention. This pedagogical approach is a framework that assesses student performance based on their ability to use their knowledge and skills, and ensures all graduates are proficient in all outlined competencies. Anatomical science is one of the foundations for clinical application, but it remains unclear to students and educators what anatomically related abilities students are expected to achieve prior to clerkship. The Schulich School of Medicine and Dentistry (The University of Western Ontario, London, Ontario, Canada) is undergoing a curriculum renewal to implement a CBME pedagogical approach. As a result, the integration of anatomy into the curriculum will be modified. To ensure our third‐year medical students are competent in the necessary fundamentals, an evidence‐based approach must be taken to integrate the anatomical sciences into the new curriculum. Thus, the specific aims of this study are to: i) develop a questionnaire to establish anatomical concepts necessary for clerkship, ii) interview all clerkship directors within UME, and iii) create an assessment to determine the anatomical knowledge base of third‐year students entering clerkship rotations. Methodology A questionnaire, targeting pre‐clerkship anatomical education, will be created and used as a guide during interviews with all clerkship directors. Information will be gathered from the clerkship directors using this questionnaire for all six clerkship rotations (family medicine, internal medicine, obstetrics and gynaecology, paediatrics, psychiatry, and surgery). The information collected will then be used to create assessments to analyze the current anatomical knowledge of third‐year students entering their clerkship year. Outcomes Information gathered from the interview questionnaire will provide insights into what anatomical knowledge students should be able to apply to clinical scenarios before starting each clerkship rotation. Furthermore, this interview should also reveal anatomical concepts that could be taught in the clerkship year to integrate basic science learning with clinical learning. The same information will be utilized to create an assessment, which will be used to determine if our third‐year clerks are currently prepared, in regards to their anatomical knowledge application, within the current UME curriculum. Discussion The primary goal of CBME is to produce physicians who are well‐equipped with the knowledge, skills, and attitudes needed to successfully practice medicine. Anatomical knowledge is one fundamental for this success. Information collected form clerkship directors, in regards to the application high‐yield anatomical knowledge necessary for third‐year clerks, will be linked to expected abilities and milestones defined by the competency‐based UME curriculum. Furthermore, the data collected from the assessments will provide evidence to inform how we design and deliver anatomy in the renewed CBME curriculum at the Schulich School of Medicine and Dentistry.

Injury to the nerves of the aortic- and superior hypogastric plexuses during retroperitoneal surgery often results in significant post-operative complications, including retrograde ejaculation and/or loss of seminal emission in males. Although previous characterizations of these plexuses have done well to provide a basis for understanding the typical anatomy, additional research into the common variations of these plexuses could further optimize nerve-sparing techniques for retroperitoneal surgery. To achieve this, the present study aimed to document the prevalence and positional variability of the infrarenal lumbar splanchnic nerves (LSNs) through gross dissection of 26 human cadavers. In almost all cases, two LSNs were observed joining each side of the aortic plexus, with 48% (left) and 33% (right) of specimens also exhibiting a third joining inferior to the left renal vein. As expected, the position of the LSNs varied greatly between specimens. That said, the vast majority (98%) of LSNs joining the aortic plexus were found to originate from the lumbar sympathetic trunk above the level of the inferior mesenteric artery. It was also found that, within specimens, adjacent LSNs often coursed in parallel. In addition to these nerves, 85% of specimens also demonstrated retroaortic LSN(s) that were angled more inferior compared with the other LSNs (P<0.05), and exhibited a unique course between the aorta/common iliac arteries and the left common iliac vein before joining the superior hypogastric plexus below the aortic bifurcation. These findings may have significant implications for surgeons attempting nerve-sparing procedures of the sympathetic nerves in the infrarenal retroperitoneum such as retroperitoneal lymphadenectomies. We anticipate that the collective findings of the current study will help improve such retroperitoneal nerve-sparing surgical procedures, which may assist in preserving male ejaculatory function post-operatively.

Introduction The direct anterior approach for total hip replacements has reported advantages of improved early function and muscle preservation. In an effort to improve healing and cosmesis, a change in the orientation of the incision has been proposed. Traditionally, the skin incision is in-line with the tensor fasciae latae muscle belly. The bikini incision is orthogonal to this orientation. The hypothesis was that muscle damage would be increased by using the bikini incision. Methods A traditional or bikini incision was performed on 18 cadaveric hips. On each of the 9 specimens, the traditional incision was performed on 1 side, and a bikini incision on the contralateral hip, with an even distribution of right or left side. Blinded anatomists performed the hip dissections, and assessed for muscle damage as well as for damage to the lateral femoral cutaneous nerve. Results No difference in muscle damage was identified in the tensor fasciae latae between muscle groups. Muscle damage was very minimal to the gluteus medius and minimus. Damage to the lateral femoral cutaneous nerve occurred equally for both the bikini and traditional skin incisions. Conclusions The bikini incision for the direct anterior approach to the hip can be performed safely, with no increase in muscle damage or damage to the lateral femoral cutaneous nerve compared to the traditional incision.

Introduction The interscalene block (ISB) is the gold standard regional anesthetic for shoulder surgery, but invariably results in ipsilateral hemi‐diaphragmatic paralysis due to phrenic nerve involvement. Isolated blocks targeting the suprascapular and axillary nerves separately have been shown to be less effective than the gold standard. The specific aim of this study was to develop a novel peripheral block for shoulder surgeries that would avoid phrenic nerve involvement and associated hemi‐diaphragm paralysis, while still providing adequate anesthesia of the targeted nerves to provide a suitable alternative to the gold standard. It was hypothesized that a subscapularis plane block (SPB), as a single injection, would provide a novel technique to block the suprascapular nerve, axillary nerve, and the upper and lower subscapular nerves. Methodology Bilateral, ultrasound‐guided (Sonosite M‐Turbo) SPB blocks were performed with a linear probe (13‐6 MHz) on 4 fresh cadavers (n = 8) using 5% dextrose with methylene blue dye as injectate (2 – 10 mLs). With the transducer aligned in the sagittal plane and moving medially, first the head of the humerus was identified, then the bicipital groove, then the coracoid process. Medial to the coracoid process, from superior to inferior, the skin, subcutaneous tissue, deltoid, pectoralis major, pectoralis minor, subscapularis muscles, and subscapular fossa were identified. An insulated Tuohy needle (17 gauge × 80 mm) was used to deposit the injectate above the fascia of the subscapularis muscle. Each cadaver was dissected to note the spread of injectate. The first set of 4 blocks were performed to determine the location of the block, while the second set of 4 blocks were performed to replicate the successful block and standardize the volume used. Results Overall, 37.5% of the blocks (3/8) performed were successful in staining all of the target nerves. 37.5% of the blocks (3/8) performed resulted in the injectate spreading along the axillary sheath into the axilla, staining the posterior cord and the lateral cord, but not the suprascapular nerve. 25% of the blocks (2/8) performed resulted in the injectate spreading deep to the subscapularis fascia into the joint. 100% of the blocks spared the phrenic nerve. Discussion The angle of the needle appears to factor into the success of the block, as the injectate spread into the axilla when angled more laterally instead of perpendicular to the injection site. Ultrasound visualization of the subscapularis plane in cadavers also contributed to the blocks success rate, as the needle was sometimes inserted deep to the subscapularis fascia, resulting in spread of the injectate to the joint capsule. A single injection, phrenic nerve sparing SPB may be a viable alternative to the gold standard for shoulder surgery anesthetic management. A clinical trial is currently underway to establish the efficacy of the SPB compared to the ISB.

Objective: A variable that necessitates conversion to a conventional full-sternotomy coronary artery bypass procedure from a robotic-assisted endoscopic single-vessel small thoracotomy is the inability to visualize the left anterior descending coronary artery within the surrounding epicardial adipose tissue using the endoscopic camera. The purpose of this study was to determine whether anatomical properties of the epicardial adipose tissue examined using preoperative computed tomography (CT) images are able to predict and thus reduce the need for intraoperative conversion based on effective preoperative exclusion criteria.Methods: Retrospective analysis of patient preoperative CT angiography scans from both converted (n = 17) and successful robotic-assisted (n = 17) procedures was performed. Where possible, measurements of epicardial adipose tissue were acquired from axial slices, at the most accessible segment of the left anterior descending coronary artery.Results: Results indicate that patients who successfully underwent the endoscopic single-vessel small thoracotomy procedure (mean +/- SD depth, 4.9 +/- 1.9 mm) had significantly less epicardial adipose tissue (38%, P = 0.002) overlying the vessel toward the lateral chest wall than those who were converted to the full-sternotomy approach intraoperatively (mean +/- SD depth, 7.9 +/- 3.2 mm). Using this as a retrospective exclusion criterion reduces the conversion rate for this group by 47%, while maintaining a high specificity (94%). No significant differences exist between the two groups with respect to the remaining epicardial adipose tissue measurements or body mass index.Conclusions: The addition of CT angiography measurements of the epicardial adipose tissue overlying the left anterior descending coronary artery may enhance preoperative surgical planning for this procedure, thereby reducing the instances of procedural changes.

FIGURE 1. Hourglass pattern formed by sartorius, internal oblique, and iliacus. I read with keen interest the article by Desmet et al, “A Longitudinal SupraInguinal Fascia Iliaca Compartment Block Reduces Morphine Consumption After Total Hip Arthroplasty.” I would like to highlight the lacunae in their block performance technique. The authors mention 38% patients have unclear demarcation of fascia iliaca and the underlying muscles, which would not be acceptable for block performance. The explanation of the correct technique would improve the pattern recognition and the success rate of the block. In their Figure 1, the authors have shown bow-tie sign over the anterior superior iliac spine, which is anatomically not correct. The pattern recognition shown in their Figure 1 can only be seen superior to anterior inferior iliac spine. A simplified technique for suprainguinal fascia iliaca block has been described previously by Singh and Jones. It involves placing the probe longitudinally on the anterior superior iliac spine, pointing midway between the xiphisternum and the umbilicus. The probe is moved medially along the inguinal ligament, maintaining the same angulation until the hourglass/bow-tie pattern is reached (Figs. 1, 2). The lateral part of the hourglass is the sartorius muscle and the medial part being the internal oblique. The hourglass is superficial to the iliacus muscle, and injecting local anesthetic between

Objective A variable that necessitates conversion to a conventional full-sternotomy coronary artery bypass procedure from a robotic-assisted endoscopic single-vessel small thoracotomy is the inability to visualize the left anterior descending coronary artery within the surrounding epicardial adipose tissue using the endoscopic camera. The purpose of this study was to determine whether anatomical properties of the epicardial adipose tissue examined using preoperative computed tomography (CT) images are able to predict and thus reduce the need for intraoperative conversion based on effective preoperative exclusion criteria. Methods Retrospective analysis of patient preoperative CT angiography scans from both converted (n = 17) and successful robotic-assisted (n = 17) procedures was performed. Where possible, measurements of epicardial adipose tissue were acquired from axial slices, at the most accessible segment of the left anterior descending coronary artery. Results Results indicate that patients who successfully underwent the endoscopic single-vessel small thoracotomy procedure (mean ± SD depth, 4.9 ±1.9 mm) had significantly less epicardial adipose tissue (38%, P = 0.002) overlying the vessel toward the lateral chest wall than those who were converted to the full-sternotomy approach intraoperatively (mean ± SD depth, 7.9 ± 3.2 mm). Using this as a retrospective exclusion criterion reduces the conversion rate for this group by 47%, while maintaining a high specificity (94%). No significant differences exist between the two groups with respect to the remaining epicardial adipose tissue measurements or body mass index. Conclusions The addition of CT angiography measurements of the epicardial adipose tissue overlying the left anterior descending coronary artery may enhance preoperative surgical planning for this procedure, thereby reducing the instances of procedural changes.