Fresh Cadaver Model Research Articles

The efficacy of two commercially available devices for airway foreign body relief: A cadaver study.

Foreign body aspiration events are frequent in young children and in the geriatric population. They may result in several complications such as hypoxia, edema, cardiac arrest, and death. Recently, two commercially available devices, the LifeVac and DeChoker, have entered the market with the claim of relieving foreign body aspiration. Both devices are portable, nonpowered, suction devices that are being considered for use in large public spaces such as schools, airports, and malls despite previous studies detailing variable efficacy. In this study, we aim to contribute further data on the safety and efficacy of these devices through a fresh cadaver model. Commonly aspirated foods of three different sizes (saltines, grapes, and cashews) were placed at the level of the true vocal folds in a fresh cadaver. Three participants performed two trials with each food and device. Device use was performed to manufacturer specifications. The DeChoker resulted in gross injury to the tongue and failed to remove the obstruction in all trials. LifeVac was successful in removing the barium-moistened saltines but failed to remove all other foreign bodies. Both devices applied significant pressure to the tongue. With the exception of the LifeVac removing saltine crackers, all trials were entirely unsuccessful in relieving foreign body aspiration. Additionally, both devices may cause significant pressure and injury to the oral cavity in a clinical setting. We conclude bystanders should continue to follow International Liaison Committee on Resuscitation's guidelines on resuscitation to aid with relieving foreign body aspiration. 4.

Radical Vaginal Hysterectomy, Type B: An Educational Video, Cadaver Model.

The radical vaginal hysterectomy popularized by Schauta1 has been virtually abandoned due to painful perineal incision, high rate of urinary dysfunction, and inability to perform lymph node assessment. However, this approach is still used and taught in a few centers outside its Austrian birthplace. In addition, a combined vaginal and laparoscopic approach, overcoming the flaws of the pure vaginal technique, was developed in the 1990s by French and German surgeons.2 After the publication of the Laparoscopic Approach to Cervical Cancer trial,3 the radical vaginal approach has found a very timely application with the closure of the vaginal cuff, aiming at avoiding cancer cell spillage.4 In addition, it is the basis to perform radical vaginal trachelectomy, or Dargent's operation, the best documented approach for the fertility-sparing management of stage IB1 cervical cancers. Today, the main obstacle to the rebirth of radical vaginal surgical surgery is the lack of teaching centers and the need of a specific learning curve that requires performing 20-50 surgeries.5,6 This educational video demonstrates that training is possible using a fresh cadaver model. A type B approach according to the Querleu-Morrow7 classification of radical vaginal hysterectomy, adapted according to surgeon's choice to stage IB1 or IB2 cervical cancer, is shown. Key specific steps such as the creation of a vaginal cuff and the identification of the ureter within the bladder pillar are highlighted. Fresh cadaver model is a method that spares the patients the risks of early learning curve while allowing the surgeon to acquire skills and keep offering the patient the benefit of the most specifically gynecological approach in cervical cancer surgery.

Influence of Rigor Mortis on Tendon Mobility in an Animal Fresh Cadaver Model.

Simple SummaryIn biomechanical research, fresh frozen cadaver material and embalmed specimens are often used to evaluate surgical approaches. Unlike, biomechanical research using fresh cadaver material is rare. There are no reliable data on the point of time when rigor mortis starts to have an impact on results with fresh cadaver material. In this study, the authors have conducted measurements using fresh porcine cadaver tendons of the supraspinatus muscle post mortem to determine the time of onset and the influence of rigor mortis on specimen tissue. 151 min post mortem, a significant decrease in tendon mobility was observed. Therefore, the authors of the presented study concluded that the onset of rigor mortis started 151 min post mortem and decreased the mobility of the tendon. Hence, biomechanical research using fresh cadaver material should ideally be conducted within 150 min post mortem to obtain in vivo-like results without being impacted by rigor mortis.(1) Many biomechanical studies are performed using fresh frozen cadavers or embalmed specimens, although the biomechanical characteristics do not match the characteristics of in vivo tendons. Therefore, a fresh in vivo-like cadaver model has been introduced recently. As a limitation for studies with fresh cadavers, rigor mortis must be considered. The aim of this study was to evaluate the impact of the biomechanical properties and time of occurrence of rigor mortis in a fresh cadaver model. (2) For this study, 15 fresh porcine cadaver shoulders were used in an established biomechanical in vitro model to evaluate the onset of rigor mortis. Measurements took place at ten points of time (t1–t10) beginning 103 min post mortem (pm). The mobility of the supraspinatus tendon was measured in Newton (N) with a modified sensor-enhanced arthroscopic grasper. (3) The mean load measured at the time point t1 was 28.0 ± 11.2 N. The first significant decrease of mobility occurred 151 min post mortem (t4) at a mean load of 30.2 ± 13.7 N. From 227 min pm to 317 min pm, there was no further significant increase. (4) Tendon mobility decreases significantly within the first three hours after the killing. Therefore, reliable results can be obtained within 150 min post mortem before the onset of rigor mortis alters the biomechanical properties.

Cadaveric and Ultrasound Validation of Percutaneous Electrolysis Approach at the Achilles Tendon as a Potential Treatment for Achilles Tendinopathy: A Pilot Study.

Achilles tendon tendinopathy (AT) is a musculoskeletal condition characterized by pain in the Achilles tendon and impaired physical performance or sport activities. AT is difficult to treat, and the results are variable. Preliminary evidence suggests a positive effect for pain of percutaneous electrolysis in patients with tendinopathy. Our aim was to determine the validity and safety of a percutaneous electrolysis approach targeting the interphase between the Achilles tendon and the Kager’s fat with ultrasound imaging in both healthy individuals and on a fresh cadaver model (not ultrasound guiding). A needle was inserted from the medial to the lateral side under the body of the Achilles tendon, just between the tendon and the Kager’s triangle, about 5 cm from the insertion of tendon in the calcaneus in 10 healthy volunteers (ultrasound study) and 10 fresh cadaver legs. An accurate needle penetration of the interphase was observed in 100% of the approaches, in both human and cadaveric models. No neurovascular bundle of the sural nerve was pierced in any insertion. The distance from the tip of the needle to the sural nerve was 5.28 ± 0.7 mms in the cadavers and 4.95 ± 0.68 mms in the volunteer subjects, measured in both cases at a distance of 5 cm from the insertion of the Achilles tendon. The results of the current study support that percutaneous electrolysis can be safely performed at the Kager’s fat–Achilles tendon interphase if it is US guided. In fact, penetration of the sural nerve was not observed in any needle approach when percutaneous needling electrolysis was performed by an experienced clinician. Future studies investigating the clinical effectiveness of the proposed intervention are needed.

Obstetric hemorrhage and surgical emergencies training workshops on fresh cadavers and simulators result in high application in daily practices and decreased patient referral.

Objective:In this study, we aimed to evaluate the effects of obstetric emergencies workshops combining theoretical lectures, simulation trainers and fresh cadaver models on daily practices and referrals of obstetrics and gynecology specialists.Materials and Methods:This is a prospective observational study involving obstetrics and gynecology specialists attending the Turkish Society of Obstetrics and Gynecology endorsed obstetrics hemorrhage management courses held in 2018 and 2019. The training course is an annually organized two-day course, one day allotted to theoretical lectures and the other day to practical training on both simulators and fresh cadavers. Trainees participating in the course was surveyed with an anonymous questionnaire on their motivation to attend the course and their juridical history of obstetric patient management. Attendees were asked to disclose whether they had ever independently performed the procedures stated in the questionnaire or not, before commencing the course and 1 year after attending the course.Results:Among the attendees 22% (n=32) had at least one obstetrical malpractice lawsuit and 36.1% (n=52) were accused of Health Care Complaints Comission. The main motivation of the attendees for taking this course was Professional development followed by reducing maternal mortality and morbidity and avoiding malpractice. One year after the course, attendees applying uterine devascularization surgery increased by 36.1% (52/144), uterine compression sutures increased by 52.7% (76/144), and ability to apply uterine balloon tamponade increased by 59.7% (86/144). Besides improvement in other obstetric surgical skills an indirect effect seen that the attandees operated on high-risk cases increased in placenta previa (15.3%), placenta acreata spectrum (30.5%), operative deliveries (27.7%), peripartum hysterectomy (24.9%) and relaparotomy for postpartum hemorrhage (34.7%).Conclusion:Opportunities of attending well organized fresh cadaveric workshops on managing postpartum hemorrhage and other obstetric surgeries, can quickly adapt to daily practice, restore the professional confidence of obstetric and gynecology specialists, and eventually decrease patient referral.

Eye-Tracking Technology to Determine Procedural Proficiency in Ultrasound-Guided Regional Anesthesia.

Eye-tracking measures attention patterns, which may offer insight into evaluating procedural expertise. The purpose of this study was to determine the feasibility of using eye tracking to assess visual fixation patterns when performing an ultrasound-guided regional anesthesia procedure and to assess for differences between experienced, intermediate, and novice practitioners. Participants performed an ultrasound-guided sciatic nerve block 3 times on a fresh cadaver model while wearing eye-tracking glasses. Gaze fixation and dwell time on each location were compared between participants. Eye-gaze paths were used to derive a measure of entropy, or how often participants switched gaze fixations between locations. Five attending anesthesiologists, 5 third-year anesthesiology residents with prior ultrasound-guided regional anesthesia experience, and 5 medical students completed the study. Individuals with more experience were more likely to successfully perform the sciatic nerve block (5/5 attendings, 5/5 residents, 0/5 students; P = .002) and performed the procedure faster (average: attendings 62.6 seconds, residents 106.4 seconds, students 134.4 seconds; P = .089). Participants were progressively faster with practice (Trial 1: 41.8 seconds, Trial 2: 29.2 seconds, Trial 3: 28.9 seconds; P = .012), and the average number of eye shifts per trial decreased from 10.8 to 6.5 to 6 (P = .010). Attending physicians spent significantly less time fixating on the ultrasound monitor compared to trainees (P = .035). Average visual entropy progressively decreased from Trial 1 to Trial 3 (P = .03) and with greater experience (P = .15). There was a strong correlation between entropy and time on task (r(16) = 0.826, P = .001). Experienced providers make fewer back-and-forth visual fixations, spend less time in the procedure, and demonstrate less entropy during ultrasound-guided regional anesthesia procedures. Mobile eye-tracking has the potential to provide additional objective measures of performance that may help not only determine procedural competence but also distinguish between levels of proficiency.

Abstract No. : ABS0260: Comparison of phantom cadaver based simulations with blue phantom model for teaching ultrasound guided regional anaesthesia: a randomised controlled trial

Background and Aims:Various methods of simulation have different advantages and disadvantages.This study was aimed to compare the block performance of novice post-graduate students of anaesthesiology after teaching them ultrasound guided regional anaesthesia on blue phantom model or cadaver-based phantom model.Methods:This study was conducted in the Department of Anaesthesiology and Critical Care and Department of Anatomy at a tertiary medical college hospital.Video lecture on ultrasound knobology and transducer movement was given to all study participants. In group BP, participants trained on blue phantom model. In group CP, participants trained on fresh human cadaver model. After training, participants were shown video of supraclavicular brachial plexus block,and finally performance was assessed on patients.Results:The median block performance time was 525.0 seconds in group BP with an interquartile(IQR) of (494-552.5) and 440.0 seconds in group CP with an IQR of (419.5-487.5)(table 1).Table 1Block performance time between the groupsGroup BP (n=25) Median (interquartile range)Group CP (n=25) Median (interquartile range) P Block performance time (in sec)525.0 (494-552.5)440.0 (419.5-487.5)<0.001This difference was statistically significant (p<0.001). The median image quality score was 3.0 in group BP with an IQR of 2-3, and it was also 3.0 in group CP with an IQR of 3-4, and it was statistically significant (p = 0.00398) (table 2).Table 2Ultrasonographic image quality in the two groupsImage quality scoreGroup BP (n=25) n (%)Group CP (n=25) n (%)Unsatisfactory00Poor7 (28)0Satisfactory15 (60)14 (56)Outstanding3 (12)11 (44)Conclusion:Time taken to perform brachial plexus block was less in the cadaver phantom group compared to the blue phantom group. The image quality scores and number of attempts required to perform brachial plexus block were statistically significant between groups. Novices trained on cadavers had better transducer target orientation and were able to identify ultrasonographic artifacts better than those trained on the blue phantom.

Feasibility of pneumoperitoneum diagnosis using point-of-care ultrasound: a pilot study using a fresh cadaver model.

To assess the accuracy of point-of-care ultrasound (PoCUS) in the hands of two trained and blinded emergencyphysicians (EPs) in detecting very small amounts of free intraperitoneal air injected intra-abdominally, using a fresh humancadaver model. Fifteen cadavers were injected on 3 occasions with predefined quantities of free intraperitonealair ranging from 0-10 mL. Seven cadavers were injected in the mid-epigastrium (ME), while 8 were injected inthe left lower quadrant (LLQ). Each cadaver was scanned after each of the 3 injections by 2 trained and blinded EPs, resultingin 45 scans per sonographer. Scans were performed using previously validated and standardized techniques. All scans wererecorded, time-stamped and labeled. For each scan the sonographers indicated "yes" or "no" to whether pneumoperitoneumwas detected. A chi square analysis was performed to determine the sensitivity and specificity of PoCUS utilized by each sonographerof pneumoperitoneum based on the location and volume of air injected. Free air (0.25-10 mL) injected intothe ME was successfully diagnosed in 36/42 instances (86% sensitivity), but only detected in 10/36 instances when injectedinto the LLQ (28% sensitivity). Both EPs detected all air injections of ≥2 mL into the ME. Detection of free airoriginating from the midepigastric region may become a future PoCUS indication for adequately trained EPs.

Biomechanical analysis of the interval slide procedure: a fresh porcine cadaver study.

The interval slide procedure (IS) has been introduced to improve mobility in massive, retracted rotator cuff tears. As clinical studies showed controversial results, the benefit of the IS is still widely discussed. Aim of this study was to analyze the effect of IS procedure on tendon mobility in a fresh porcine cadaver model. In 30 fresh porcine cadaver shoulders with artificial supraspinatus defect tendon mobility was tested by measuring the load (in N) during tendon reduction to the footprint at the greater tubercle using a sensor enhanced arthroscopic grasper (t1). In intervention group (N = 15) anterior IS (t2), posterior IS (t3) and intraarticular capsule release (t4) were successively performed, each followed by tendon mobility assessment. Tendon mobility of the control group (N = 15) was measured in same time schedule without intervention. Mobility did not differ between groups for native tendons (CG 28.0 ± 11.2 N vs. IG 26.6 ± 11.6 N; P = 0.75). IS procedure significantly improves mobility at about 25.2% (t1 26.6 ± 11.6 N vs. t4 19.9 ± 12.3 N; P < 0.001) compared to the native tendon and 34.1% compared to CG (CG 30.2 ± 13.7 N vs. 19.9 ± 12.3 N; P = 0.026). In posthoc analyzes, anterior IS (P < 0.001) and capsule release (P = 0.005) significantly increased mobility, whereas the posterior IS did not (P = 0.778). The IS procedure results in increased supraspinatus tendon mobility in fresh porcine cadaver shoulders. However, performing the posterior IS subsequent to the anterior IS no significant improvement of mobility has been observed.

Complications of Learning Curve in Supratentorial Intraventricular Region. The Concept of Fast Daily Fresh Cadaver Practice. (Technical Note for Training Method)

Background: The difficulty of learning curve in different microsurgical regions is one of the most challenging factors that affect neurosurgeon’s life. Two of the delicate areas are the suprasellar intraventricular and pontocerebellar region. High level of microsurgery or endoscopic surgery requires virtuosity, which can not be learnt only by assisting. Even among the well skilled neurosurgeons who work in big centers we can often hear “in spite of centralization there are not enough operations available to keep the high level of our skills”. The situation of surgeons working at mid centers is more difficult especially on duties. Methods: Huge number of scientific articles demonstrate the importance of different types of cadaver practice, but always did not pay enough attention to the daily fast fresh cadaver exercises. Focusing on lifelong every day practice we examined the difficulties of learning curve in intraventricular and pontocerebellar region and try to give some useful advice for practicing on fresh cadavers on a daily basis. We offer a simple endovascular fresh cadaver model for practicing. Results: We have performed more than 800 quick (60 - 90 minutes long) routine practice sessions in these two regions during last 18 years. We found that implantation a modelized pathology and removing it by microscopical or endoscopic way without causing injuries to sensitive structures seems to be the most practical way of fast everyday training. Nerves and vascular bypass sutures are also excellent practical method. Conclusions: We have focused on daily fast fresh cadaver practice as a novel training method like used in professional sport and art. After 18 years experience we can state that, for mastering the microsurgery of pontocerebellar and intraventricular region, which is one of the most challenging regions minimum 100 fresh cadaver practice sessions need before performing the operation. We believe this region should be part of fast fresh cadaver microsurgical practice routine programme on daily bases, minimum one time/week/person.

Fresh Cadaver Simulation Model with Continuous Extracorporeal Circulation as a Training Platform for Intracranial High-Flow Bypass: Technical Note and Rheologic Feasibility Evaluation.

Introduction As endovascular techniques evolve toward replacing open surgery, several clinical scenarios still require surgical revascularization. Characterizing this era are decreasing surgical volumes and lack of realistic training models. In an effort to develop lifelike simulation models, we developed a platform for surgical training on high-flow bypass in a fresh cadaver model. Our technique incorporated an extracorporeal circulating system that resembled clinical conditions and confirmed anastomosis efficacy by clinical parameters. Methods On three fresh cadaveric heads, the subtemporal approach exposed the petrous internal carotid artery (ICA) (C2) as the donor vessel for an interposition radial artery graft. Using a continuous extracorporeal circulation system, the bypass model was tested in three fresh heads and verified using clinical technologies. Results Successful C2 ICA to M2 anastomosis was completed in all three fresh heads, confirmed with qualitative and quantitative Doppler, and indocyanine green angiography. Antegrade distribution through graft and revascularized territory was documented on postoperative computed tomography (CT) scan with radiopaque silicone injected through the ipsilateral carotid. Conclusion This study confirmed the feasibility of a totally intracranial high-flow bypass in a fresh cadaver model that achieved hemodynamic features aligned with those of normal middle cerebral artery flow in the clinical setting.

Extension Mechanism of the Proximal Interphalangeal Joint of the Human Phalanx: A Cadaveric Biomechanical Study.

Our purpose was to compare the contributions of these two systems to assess PIP joint extension in fresh cadaver models. Nine middle fingers of fresh cadavers were used. The PIP joint angle was measured while an extension load was applied on the extensor tendons. Specimens on which extension load was applied on the extrinsic extensors were classified as the extrinsic group, and those on which extension load was applied on the intrinsic extensors were classified as the intrinsic group. Linear regression analyses were performed to obtain regression equation and the extension load-PIP joint angle curve. The mean of slope of the curve was compared between the two groups using paired t-test. The same experiments were done for the metacarpophalangeal (MP) joint in 0° and 60° flexion to evaluate the effect of MP joint flexion on PIP joint extension. The mean slope of the extension load-PIP joint angle curve of the extrinsic group was significantly greater than that of the intrinsic group. With the MP joint in 0° flexion, the mean slope of the extrinsic and intrinsic groups was -0.148 and -0.117, respectively (greater absolute value means greater slope, p = 0.01). With the MP joint in 60° flexion, the mean slopes were -0.147 and -0.104, respectively (p = 0.015). The contribution of the intrinsic extensor for PIP joint extension shows decreasing trends with MP joint flexion. The extrinsic extensors have greater contribution for PIP joint extension compared with the intrinsic extensors.

Brief report on combat trauma surgical training using a perfused cadaver model.

Surgical combat casualty care presents difficult training challenges. Although several high-fidelity simulation (SIM) techniques have emerged, none are able to fully integrate the many intricacies involved in the care of a complex trauma patient. Herein, we report the use of perfused fresh human cadaver model for training and assessment of forward surgical teams (FSTs). Forward surgical teams attend a 4-day combat trauma surgical skills course including focused on trauma exposures. A half-day SIM involves the entire surgical team in four sequential surgical scenarios that involve the neck, chest, abdomen, and extremities, as well as airway management and resuscitation. Teams undergo immediate debriefing and videotape review of team dynamics and technical skills, as well as times to completion of critical interventions. The data evaluated include five initial demonstration courses in which training metrics were available. Each team included both a junior and experienced surgeon, anesthesiologists, and surgical scrub technicians. As FSTs progressed through SIMs, they demonstrated improvements in team dynamics and technical skills evaluations. There was considerable variability in the times to completion of critical intervention, particularly for control of cardiac and vascular injuries. Initial evaluations support the use of this novel perfused cadaver model for the training and evaluation of military FSTs. Preliminary data highlight the utility for open vascular, thoracic, and other high-acuity/low-volume procedures critical to combat casualty care. Larger studies are needed for model optimization and further validation of an objective structured technical assessment tool. Care management, level V.

Concomitant Anterior and Posterior Component Separations: Absolutely Contraindicated?

Many experts in abdominal wall reconstruction believe that the combination of simultaneous ipsilateral anterior component separation (ACS) and posterior component separation (PCS) is contraindicated. We performed ipsilateral endoscopic ACS and either endoscopic or open PCS-transversus abdominis release (TAR) in 5 fresh cadaver models. The full length of the semilunar line and the lateral abdominal wall remained well reinforced by 2 complete layers, comprising the internal oblique (IO) and TA muscles and their investing fasciae. Myofascial releases occurred 4 cm (median) apart. Additionally, we reviewed computed tomography images at 1 month and 1 year after PCS-TAR in 17 patients (30 PCS-TARs). Lateral displacement of the TA relative to the rectus abdominis (RA) was significant only at the superior mesenteric artery level, where it was <1 cm (median). Muscle mass changed minimally over time. Several studies showed that abdominal wall reconstruction after PCS-TAR results in compensatory muscular hypertrophy of the RA, external oblique (EO), and IO muscles and provides better quality of life and improved core physiology. These changes did not occur when the midline was not restored. Theoretically, endoscopic ACS-EO may be added to PCS-TAR to avoid partially bridged mesh repair in patients in whom complete midline restoration is impossible via PCS-TAR alone. Nevertheless, we advise most surgeons to perform a small-bridged repair instead of risking increased morbidity by attempting a highly complicated procedure.

Anatomical description of anaesthetic spread after deep erector spinae block at L-4

Abstract Introduction Thoracic erector spinae plane (ESP) block is now used for postoperative analgesia. However, although reports of lumbar ESP have been published, the anesthetic spread and mechanism of action of this technique remains unclear. We describe the lumbar ESP block technique and evaluate the spread of 20 ml of solution administered at the level of the transverse process of L4 in a cadaver model. Methods Observational study after 12 lumbar ESP blocks at L4 on a fresh cadaver model (6 bilaterally). The spread of 20 ml of injected contrast solution was assessed by computed tomography in all 6 samples. Four of the samples were evaluated by anatomical study, 2 by plane dissection, and 2 others were frozen and cut into 2–2.5 cm axial slices. Results The injected solution spread from L2 to L5 in a cranio-caudal direction in the erector spinae muscle, reaching the facet joints medially and the thoracolumbar fascia laterally. In 33% of cases the solution did not spread anterior to the transverse process; in 51%, spread was minimal and did not affect the corresponding spinal nerves, and in 2 samples (16%), spread was extensive and reached the corresponding spinal nerves. Conclusions Lumbar ESP at L4 always acts on the posterior branches of the spinal nerves, but seldom spreads to the paravertebral space to block the spinal nerve.

Estudio anatómico de la distribución del volumen administrado tras bloqueo en el plano profundo del erector espinal a nivel lumbar

IntroductionThoracic erector spinae plane (ESP) block is now used for postoperative analgesia. However, although reports of lumbar ESP have been published, the anesthetic spread and mechanism of action of this technique remains unclear. We describe the lumbar ESP block technique and evaluate the spread of 20ml of solution administered at the level of the transverse process of L4 in a cadaver model. MethodsObservational study after 12 lumbar ESP blocks at L4 on a fresh cadaver model (6 bilaterally). The spread of 20ml of injected contrast solution was assessed by computed tomography in all 6 samples. Four of the samples were evaluated by anatomical study, 2 by plane dissection, and 2 others were frozen and cut into 2-2.5cm axial slices. ResultsThe injected solution spread from L2 to L5 in a cranio-caudal direction in the erector spinae muscle, reaching the facet joints medially and the thoracolumbar fascia laterally. In 33% of cases the solution did not spread anterior to the transverse process; in 51%, spread was minimal and did not affect the corresponding spinal nerves, and in 2 samples (16%), spread was extensive and reached the corresponding spinal nerves. ConclusionsLumbar ESP at L4 always acts on the posterior branches of the spinal nerves, but seldom spreads to the paravertebral space to block the spinal nerve.

Preoperative surgical rehearsal using cadaveric fresh tissue surgical simulation increases resident operative confidence.

Rehearsal is an essential part of mastering any technical skill. The efficacy of surgical rehearsal is currently limited by low fidelity simulation models. Fresh cadaver models, however, offer maximal surgical simulation. We hypothesize that preoperative surgical rehearsal using fresh tissue surgical simulation will improve resident confidence and serve as an important adjunct to current training methods. Preoperative rehearsal of surgical procedures was performed by plastic surgery residents using fresh cadavers in a simulated operative environment. Rehearsal was designed to mimic the clinical operation, complete with a surgical technician to assist. A retrospective, web-based survey was used to assess resident perception of pre- and post-procedure confidence, preparation, technique, speed, safety, and anatomical knowledge on a 5-point scale (1= not confident, 5= very confident). Twenty-six rehearsals were performed by 9 residents (PGY 1-7) an average of 4.7±2.1 days prior to performance of the scheduled operation. Surveys demonstrated a median pre-simulation confidence score of 2 and a post-rehearsal score of 4 (P<0.01). The perceived improvement in confidence and performance was greatest when simulation was performed within 3 days of the scheduled case. All residents felt that cadaveric simulation was better than standard preparation methods of self-directed reading or discussion with other surgeons. All residents believed that their technique, speed, safety, and anatomical knowledge improved as a result of simulation. Fresh tissue-based preoperative surgical rehearsal was effectively implemented in the residency program. Resident confidence and perception of technique improved. Survey results suggest that cadaveric simulation is beneficial for all levels of residents. We believe that implementation of preoperative surgical rehearsal is an effective adjunct to surgical training at all skill levels in the current environment of decreased work hours.

Bloqueo ecoguiado de los nervios geniculados en el manejo analgésico de la artroplastia de rodilla: descripción de la técnica y resultados clínicos preliminares

IntroductionTotal knee arthroplasty (TKA) is an operation with moderate to severe postoperative pain. The Fast-Track models employ local infiltration techniques with anaesthetics at high volumes (100-150ml). We proposed a genicular nerve block with low volume of local anaesthetic. The aim of our study is to evaluate the periarticular distribution of these blocks in a fresh cadaver model and to describe the technique in a preliminary group of patients submitted to TKA. Materials and methodsIn the anatomical phase, 4 genicular nerves (superior medial, superior lateral, inferior medial and inferior lateral) were blocked with 4ml of local anaesthetic with iodinated contrast and methylene blue in each (16ml in total). It was performed on a fresh cadaver and the distribution of the injected medium was evaluated by means of a CT-scan and coronal anatomical sections on both knees. The clinical phase included 12 patients scheduled for TKA. Ultrasound-guided block of the 4 genicular nerves was performed preoperatively and their clinical efficacy evaluated by assessing pain after the reversal of the spinal block and at 12h after the block. Pain was measured using the numerical scale and the need for rescue analgesia was evaluated. ResultsA wide periarticular distribution of contrast was observed by CT-scan, which was later evaluated in the coronal sections. The distribution followed the joint capsule without entering the joint, both in the femur and in the tibia. The pain after the reversal of the subarachnoid block was 2±1, requiring rescue analgesia in 42% of the patients. At 12h, the pain according to the numerical scale was 4±1, 33% required rescue analgesia. ConclusionThe administration of 4ml of local anaesthetic at the level of the 4 genicular nerves of the knee produces a wide periarticular distribution. Our preliminary data in a series of 12 patients undergoing TKA seems to be clinically effective. Nevertheless, extensive case series and comparative studies with local infiltration techniques with anaesthetics are needed to support these encouraging results.

A Fresh Cadaver Model for the Instruction of Ultrasound-Guided Fine-Needle Aspiration of Thyroid Nodules.

Objective The aim of our study is to determine if a fresh cadaver model (FCM) for the instruction of ultrasound (US)-guided fine-needle aspiration (FNA) of thyroid nodules is a practical method for instruction. Study Design Pre- and postinstruction assessment of medical students' ability to perform US-guided FNA of artificially created thyroid nodules placed adjacent to the thyroid gland of a fresh cadaver. Setting University-based fresh cadaver laboratory. Subjects and Methods Study participants included a total of 17 first- and second-year medical students with minimal US training. Technical skills were assessed using a 10-item checklist. In addition, a cognitive assessment regarding the indications, contraindications, and complications of the procedure was completed. A postinstruction assessment was provided for participants 5 weeks after their initial assessment. Differences between pre- and postinstruction assessment scores of technical skills were analyzed using McNemar's test. The mean cognitive knowledge gain was analyzed using a paired 2-sample t test. Results Eight of 10 items on the skills checklist were statistically significant between pre- and postinstruction skills assessment ( P < .05). There was a statistically significant change in cognitive knowledge gain regarding the contraindications of the procedure ( P = .001), but not for indications or complications ( P = .104 and P = .111, respectively). Conclusion US-guided FNA continues to be an important diagnostic procedure in the workup of thyroid nodules, making it an essential skill to integrate into surgical skills lab. Our FCM for the instruction of US-guided FNA is the first of its kind, and this pilot study shows this is a viable method for instruction.

Medial approach of ultrasound-guided costoclavicular plexus block and its effects on regional perfussion

Abstract Introduction Ultrasound-guided infraclavicular block in the costoclavicular space located between the clavicle and the first rib, reaches the secondary trunks when they are clustered together and lateral to the axillary artery. This block is most often performed through a lateral approach, the difficulty being finding the coracoid process an obstacle and guiding the needle towards the vessels and pleura. A medial approach, meaning from inside to outside, will avoid these structures. Traditionally the assessment of a successful block is through motor or sensitive responses but a sympathetic fibre block can also be evaluated measuring the changes in humeral artery blood flow, skin temperature and/or perfusion index. Objective To describe the medial approach of the ultrasound-guided costoclavicular block evaluating its development by motor and sensitive response and measurement of sympathetic changes. Materials and methods Description of the technique and administration of 20 ml of contrast in a fresh cadaver model, evaluating the distribution with CT-scan and sagittal sections of the anatomic piece. Subsequently in a clinical phase, including 11 patients, we evaluated the establishment of motor, sensitive and sympathetic blocks. We evaluated the sympathetic changes reflected by humeral artery blood flow, skin temperature and distal perfusion index. Results In the anatomical model the block was conducted without difficulties, showing an adequate periclavicular distribution of the contrast in the CT-scan and in sagittal sections, reaching the interscalenic space as far as the secondary trunks. Successful blocks were observed in 91% of patients after 25 min. All the parameters reflecting sympathetic block increased significantly. The humeral artery blood flow showed an increase from 108 ± 86 to 188 ± 141 ml/min ( p = 0.05), skin temperature from 32.1 ± 2 to 32.8 ± 9 °C ( p = 0.03) and perfusion index from 4 ± 3 to 9 ± 5 ( p = 0.003). Conclusions The medial approach of the ultrasound-guided costoclavicular block is anatomically feasible, with high clinical effectiveness using 20 ml of 1.5% mepivacaine. The sympathetic block can be evaluated with all three parameters studied.