Toward an optimal cadaveric brain model for neurosurgical education: assessment of preservation, parenchyma, vascular injection, and imaging.

OBJECTIVE: We assessed types of cadaveric head and brain tissue specimen preparations that are used in a high throughput neurosurgical research laboratory to determine optimal preparation methods for neurosurgical anatomical research, education, and training. METHODS: Cadaveric specimens (N = 112) prepared using different preservation and vascular injection methods were imaged, dissected, and graded by 11 neurosurgeons using a 21-point scale. We assessed the quality of tissue and preservation in both the anterior and posterior circulations. Tissue quality was evaluated using a 9-point magnetic resonance imaging (MRI) scale. RESULTS: Formalin-fixed specimens yielded the highest scores for assessment (mean ± SD [17.0 ± 2.8]) vs. formalin-flushed (17.0 ± 3.6) and MRI (6.9 ± 2.0). Cadaver assessment and MRI scores were positively correlated (P < 0.001, R2 0.60). Analysis showed significant associations between cadaver assessment scores and specific variables: nonformalin fixation (ß = -3.3), preservation within ≤72 h of death (ß = 1.8), and MRI quality score (ß = 0.7). Formalin-fixed specimens exhibited greater hardness than formalin-flushed and nonformalin-fixed specimens (P ≤ 0.006). Neurosurgeons preferred formalin-flushed specimens injected with colored latex. CONCLUSION: For better-quality specimens for neurosurgical education and training, formalin preservation within ≤72 h of death was preferable, as was injection with colored latex. Formalin-flushed specimens more closely resembled live brain parenchyma. Assessment scores were lower for preparation techniques performed > 72 h postmortem and for nonformalin preservation solutions. The positive correlation between cadaver assessment scores and our novel MRI score indicates that donation organizations and institutional buyers should incorporate MRI as a screening tool for the selection of high-quality specimens.

Imaging Assessment of Peripapillary Vessel Diameters in Postmortem Eyes.

PURPOSE: Proof of concept of ex vivo retinal vessel diameter measurements in human postmortem eyes. METHODS: En face near-infrared (IR) images and optical coherence tomography (OCT) of the optic nerve head (ONH) were captured ex vivo with a Heidelberg Engineering Spectralis (Spectralis, version 7.0.4, Image Capture Module, version 1.2.4, Heidelberg Heidelberg, Germany) device, using a custom-made eye chamber holding and positioning the eyes during the image process. Thirty-two formaldehyde-fixated eyes of 16 patients were imaged. In the IR images, two independent graders measured retinal vessel diameters at the intersection of a drawn circle centered on the ONH with diameters of 2.0 mm and 3.4 mm, respectively. The anatomically corresponding measurements between both graders were statistically analyzed using a Wilcoxon signed-rank test. RESULTS: A total of 246 matched measurements of both graders were analyzed across all 32 imaged eyes. Statistically significant differences between the graders were found for arterioles at 2 mm from the ONH. The other measurements did not show statistically significant intergrader differences. The mean values for arteriole diameters were 72.2 µm at 2.0 mm and 61.5 µm at 3.4 mm for grader 1, and 66.4 µm at 2.0 mm and 63.2 µm at 3.4 mm for grader 2. The mean diameter for venules were 75.5 µm at 2.0 mm and 79.3 µm at 3.4 mm for grader 1, and 67.4 µm at 2 mm and 79.1 µm at 3.4 mm for grader 2. CONCLUSION: To the best of our knowledge, this is the first study to present IR image-based retinal vessel diameters in ex vivo postmortem eyes. Retinal IR/OCT imaging is possible, and measurements are reproducible in formaldehyde-fixated human eyes. Fixation artefacts result in lower image quality, and this can impose challenges in correctly detecting, classifying, and measuring retinal vessels.

Gross, organoleptic and histologic assessment of cadaveric equine heads preserved using chemical methods for veterinary surgical teaching.

BACKGROUND: Preservation of biological tissues has been used since ancient times. Regardless of the method employed, tissue preservation is thought to be a vital step in veterinary surgery teaching and learning. OBJECTIVES: This study was designed to determine the usability of chemically preserved cadaveric equine heads for surgical teaching in veterinary medicine. METHODS: Six cadaveric equine heads were collected immediately after death or euthanasia and frozen until fixation. Fixation was achieved by using a hypertonic solution consisting of sodium chloride, sodium nitrite and sodium nitrate, and an alcoholic solution containing ethanol and glycerin. Chemically preserved specimens were stored at low temperatures (2°C to 6°C) in a conventional refrigerator. The specimens were submitted to gross and organoleptic assessment right after fixative solution injection (D0) and within 10, 20, and 30 days of fixation (D10, D20, and D30, respectively). Samples of tissue from skin, tongue, oral vestibule, and masseter muscle were collected for histological evaluation at the same time points. RESULTS: Physical and organoleptic assessments revealed excellent specimen quality (mean scores higher than 4 on a 5-point scale) in most cases. In some specimens, lower scores (3) were assigned to the range of mouth opening, particularly on D0 and D10. A reduced the range of mouth opening may be a limiting factor in teaching activities involving structures located in the oral cavity. CONCLUSIONS: The excellent physical, histologic, and organoleptic characteristics of the specimens in this sample support their usability in teaching within the time frame considered. Appropriate physical and organoleptic characteristics (color, texture, odor, and flexibility) of the specimens in this study support the use of the method described for preparation of reusable anatomical specimens.

CT Cadaveric dataset for Radiomics features stability assessment in lumbar vertebrae.

Radiomics features (RFs) studies have showed limitations in the reproducibility of RFs in different acquisition settings. To date, reproducibility studies using CT images mainly rely on phantoms, due to the harness of patient exposure to X-rays. The provided CadAIver dataset has the aims of evaluating how CT scanner parameters effect radiomics features on cadaveric donor. The dataset comprises 112 unique CT acquisitions of a cadaveric truck acquired on 3 different CT scanners varying KV, mA, field-of-view, and reconstruction kernel settings. Technical validation of the CadAIver dataset comprises a comprehensive univariate and multivariate GLM approach to assess stability of each RFs extracted from lumbar vertebrae. The complete dataset is publicly available to be applied for future research in the RFs field, and could foster the creation of a collaborative open CT image database to increase the sample size, the range of available scanners, and the available body districts.

First standardized assessment of perforators and perforasomes of the occipital artery - An anatomical study.

BACKGROUND: Flaps have become an integral part of plastic and reconstructive surgery. The robust blood supply of such flaps is a prerequisite to reduce flap failure. Despite the reported versatility of the occipital flap, comprehensive anatomical studies on its perforators and perforasomes are lacking. Hence, we examined the perforators originating from the occipital artery and their associated perforasomes, aiming to fill this knowledge gap for reconstructive surgery techniques. METHODS: 39 of 40 occipital arteries of 20 fresh anatomical head specimens were dissected. Perforators with a least an outer diameter of 0.50 mm were identified and injected with dye to color their respective perforasomes. Location and size of the colored skin areas were determined as well as the location of their perforators were documented and analyzed. RESULTS: In total, 183 perforators were found and described. The mean diameter of these vessels was 0.88 ± 0.27 mm (0.5-2.1 mm). The mean area of the perforasomes was 1288.26 ± 662.51 mm2 (144.60-3890.60 mm2). They were localized over the whole nuchal and occipital area. Lastly, perforator diameters were significantly associated with the size of their resulting perforasomes. CONCLUSION: This study is the first comprehensive overview of perforators and associated perforasomes of the occipital artery on a respectable amount of specimen. The arterial supply of big portions of the occipital and nuchal area is provided solely by the perforators of the occipital artery. For flap surgery, perforator diameter is a crucial detail to be considered in the decision-making process.

Passive Eversion Assessment for Progressive Collapsing Foot Deformity After Lateral Column Lengthening: A Cadaveric Biomechanical Study.

BACKGROUND: Reduced hindfoot eversion motion has been proposed as a cause of increased lateral foot pressure following lateral column lengthening (LCL) for progressive collapsing foot deformity (PCFD). A subjective intraoperative assessment of passive eversion has been suggested to help evaluate correction; however, it is unclear how passive eversion correlates with objective measurements of foot stiffness. Our objectives were to quantify the relationship between the maximum passive eversion in hindfoot joints following LCL with plantar pressure during stance and to determine the influence of wedge size on these outcomes. METHODS: Ten cadaveric specimens extending from the mid-tibia distally were tested on a 6-degrees-of-freedom robot to simulate the stance phase of level walking. Five conditions were tested: intact, simulated PCFD, and 3 LCL wedge conditions (4, 6, and 8 mm). Outcomes included the lateral-to-medial forefoot plantar pressure (LM) ratio during stance and the maximum passive eversion measured in the hindfoot joints. Simple linear regressions were performed to evaluate relationships between outcomes and wedge sizes. RESULTS: A strong negative relationship was found between passive subtalar eversion and the LM ratio during stance (r[38] = -0.46; p = 0.0007), but not between passive talonavicular eversion and the LM ratio (r[38] = -0.02; p = 0.37). Wedge size was strongly related to subtalar eversion (r[38] = -0.77; p < 0.0001), talonavicular eversion (r[38] = -0.55; p = 0.0003), and the LM ratio (r[38] = 0.70; p < 0.0001). Increased wedge size resulted in average decreases in subtalar and talonavicular eversion of 1.0° (95% confidence interval [CI]: 0.8° to 1.3°) and 1.2° (95% CI: 0.6° to 1.6°), respectively. Increased wedge size also increased the LM ratio by 0.38 (95% CI: 0.25 to 0.50), indicating a lateral shift in plantar pressure. CONCLUSIONS: Decreased hindfoot eversion following LCL was related to increased lateral plantar pressure during stance. Increasing wedge size correlated with decreasing passive hindfoot eversion and increasing lateral plantar pressure, suggesting that intraoperative preservation of eversion motion may be important for preventing excessive lateral loading. CLINICAL RELEVANCE: To avoid overcorrection or undercorrection of the deformity, hindfoot eversion assessment in addition to radiographic evaluation may be important for optimizing the amount of lengthening to achieve successful LCL.

Use of thermal drone in detection and assessment of larval mass temperature in decomposed rabbit carcasses.

Manual ground searches and cadaver dogs are traditional methods for locating remains, but they can be time- and resource-intensive, resulting in the decomposition of bodies and delay in victim identification. Therefore, thermal imaging has been proposed as a potentially useful tool for detecting remains based on their temperature. This study investigated the potential of a novel search technique of thermal drones to detect surface remains through the detection of maggot mass temperatures. Two trials were carried out at Selangor, Malaysia, each utilizing 12 healthy male Oryctolagus cuniculus European white rabbits and DJI Matrice 300 RTK drone China, equipped with a thermal camera; Zenmuse H20T to record the thermal imaging footage of the carcasses at various heights (15, 30, 60-100 m) for 14 days for each trial. Our results demonstrated that the larval masses and corresponding heat emissions were at their largest during the active decay stage; therefore, all the carcasses were observable in thermal images on day 5 and remained until day 7. Statistical analyses showed that (1) no statistically significant differences in thermal images between clothed and unclothed subjects (p > 0.05); (2) 15 m above ground level was proven to be the optimal height, as it showed the greatest contrast between the carcass heat signature and the background (p < 0.005). Our data suggested the potential window of detection of thermal signatures was detectable up to 7 days post-deposition. This could be an important guideline for the search and recovery teams for operational implementation in this tropical region.

Assessment of x-ray efficacy for intraoperative microneedle retrieval using a cadaveric model.

INTRODUCTION: Institutional protocols often mandate the use of x-rays when a microneedle is lost intraoperatively. Although x-rays can reliably show a macroneedle, the benefit of x-rays in detecting microneedles in human tissues has not been established as available data on this topic are investigated in anthropometric models. The current study aims to evaluate whether x-rays can reliably detect retained microneedles in a human cadaveric model. We hypothesize that microneedles would be detected at a significantly lower rate than macroneedles by x-ray in human tissues. MATERIALS AND METHODS: Needles ranging from 4-0 to 10-0 were placed randomly throughout a cadaveric hand and foot. Each tissue sample was x-rayed using a Fexitron X-Ray machine, taking both anteroposterior and lateral views. A total of six x-ray images were then evaluated by 11 radiologists, independently. The radiologists circled over the area where they visualized a needle. The accuracy of detecting macroneedles (size 4-0 to 7-0) was compared with that of microneedles (size 8-0 to 10-0) using a chi-square test. RESULTS: The overall detection rate for the microneedles was significantly lower than the detection rate for macroneedles (13.5% vs 88.8%, p < .01). When subcategorized between the hand and the foot, the detection rate for microneedles was also significantly lower than the rate for macroneedles (hand: 7.6% for microneedles, 93.2% for macroneedles, p < .01; foot: 19.5% for microneedles, 84.4% for macroneedles, p < .01). The detection rate, in general, significantly decreased as the sizes of needles became smaller (7-0:70.5%, 8-0:18.2%, 9-0:16.7%, 10-0:2.3%, p < .01). CONCLUSION: X-rays, while useful in detecting macroneedles, had a significantly lower rate of detecting microneedles in a cadaveric model. The routine use of x-rays for a lost microneedle may not be beneficial. Further investigation with fresh tissue and similar intraoperative x-ray systems is warranted to corroborate and support these findings.

Cadaveric biomechanical assessment of different configurations for a novel pin and plate fixation method in distal humerus fractures.

Use of dual pre-contoured plates has been accepted as the treatment of choice in distal humerus fractures despite challenges especially in very distal or highly fragmented fractures. Aiming to improve results in such instances, our newly proposed method uses several K-wires fixated by a small reconstruction plate. Drawing on the results of previous finite element studies, the current study aims to compare the stiffness of three clinically common variations of this method using biomechanical testing in cadaveric humeri. 24 samples were divided into three groups and fractures were simulated. Groups I and II used 1.5 mm K-wires in differing configurations while 2 mm wires were used in group III. All samples underwent compression, anterior and posterior bending, and torsional testing as well as failure testing. Our results indicated that Group III had significantly higher stiffness in flexion, extension, and torsion (p < 0.05). In failure, group III had the highest mean stiffness in anterior bending and torsion (861.2 N, 30.9 Nm). Based on previous and current results, this new Persian fixation method, especially when implemented using 2 mm K-wires, shows promise in achieving suitable stability and may be useful as an alternative approach in complex distal humerus fractures.

Clinical and Anatomical Variation During Assessment of Maximum Glottic Angle.

INTRODUCTION: Quantitative measurement and analysis of glottic abduction is used to assess laryngeal function and success of interventions; however, the consistency of measurement over time has not been established. This study assesses the consistency of glottic abduction measurements across visits in healthy patients and anatomic factors impacting these measurements. METHODS: Review of patients with two sequential flexible stroboscopic exams over seven months from 2019-2022. Images of maximal glottic abduction were captured and uploaded into and measured with ImageJ. Cadaver heads were used to assess the impact of visualization angles on glottic measurements with a monofilament inserted into the supraglottis of each cadaver as a point of reference. Comparisons were done with a paired T-test, T-test, or Mann-Whitney U test as appropriate. RESULTS: Fifty-nine patients and twenty-six cadaveric exams were included. Absolute change in maximum glottic abduction angle (MGAA) was 6.90° (95% CI [5.36°, 8.42°]; p < 0.05). There were no significant differences in change in MGAA by gender or age. Twenty percent of patients had a change of at least 25% in their MGAA between visits. Absolute differences in glottic angle between nasal side for cadaveric measurements was 4.77 ± 4.59° (p < 0.005)-2.22° less than the change in MGAA seen over time (p = 0.185). CONCLUSION: Maximal glottic abduction angles varied significantly between visits. Factors considered to be contributing to the differences include different viewing windows between examinations due to the position and angulation of the laryngoscope and changes in patient positioning, intra- and inter-rater variations in measurement, and patient effort. LEVEL OF EVIDENCE: N/a Laryngoscope, 134:2793-2798, 2024.

Role of Lateral Extra-articular Tenodesis in Restraining Internal Tibial Rotation: In Vitro Biomechanical Assessment of Lateral Tissue Engagement.

BACKGROUND: The way in which force increases in the anterolateral tissues and the lateral extra-articular tenodesis (LET) tissue to resist internal rotation (IR) of the tibia after anterior cruciate ligament (ACL) reconstruction in isolation and after LET augmentation, respectively, is not well understood. PURPOSE: (1) To compare in a cadaveric model how force increases (ie, engages) in the anterolateral tissues with IR of the tibia after isolated ACL reconstruction and in the LET tissue after augmentation of the ACL reconstruction with LET and (2) to determine whether IR of the tibia is related to engagement of the LET tissue. STUDY DESIGN: Controlled laboratory study. METHODS: IR moments were applied to 9 human cadaveric knees at 0°, 30°, 60°, and 90° of flexion using a robotic manipulator. Each knee was tested in 2 states: (1) after isolated ACL reconstruction with intact anterolateral tissues and (2) after LET was performed using a modified Lemaire technique with the LET tissue fixed at 60° of flexion under 44 N of tension. Resultant forces carried by the anterolateral tissues and the LET tissue were determined via superposition. The way force increased in these tissues was characterized via parameters of tissue engagement, namely in situ slack, in situ stiffness, and tissue force at peak applied IR moment, and then compared (α < .05). IR was related to parameters of engagement of the LET tissue via simple linear regression (α < .05). RESULTS: The LET tissue exhibited less in situ slack than the anterolateral tissues at 30°, 60°, and 90° of flexion (P≤ .04) and greater in situ stiffness at 30° and 90° of flexion (P≤ .043). The LET tissue carried greater force at the peak applied IR moment at 0° and 30° of flexion (P≤ .01). IR was related to the in situ slack of the LET tissue (R2≥ 0.88; P≤ .0003). CONCLUSION: LET increased restraint to IR of the tibia compared with the anterolateral tissue, particularly at 30°, 60°, and 90° of flexion. IR of the tibia was positively associated with in situ slack of the LET tissue. CLINICAL RELEVANCE: Fixing the LET at 60° of flexion still provided IR restraint in the more functionally relevant flexion angle of 30°. Surgeons should pay close attention to the angle of internal and/or external tibial rotation when fixing the LET tissue intraoperatively because this surgical parameter is related to in situ slack of the LET tissue and, therefore, the amount of IR of the tibia.

Why identification matters: an explorative study on six cases of family reunification.

The escalating phenomenon of migration, accompanied by a disturbing surge in associated tragedies, has persistently violated internationally protected human rights. Absence of physical evidence, namely the presence of adequately identified corpses, may impede the full enjoyment of human rights and-in some cases-the course of justice as it obstructs the initiation of legal proceedings against individuals implicated in causing such catastrophes. It also presents administrative obstacles, as death certificates are indispensable in legitimizing statuses like orphanhood and widowhood. Family reunification, particularly for orphans, plays a significant role for those attempting to reconnect with their relatives all over the world. Likewise, for mothers, the acknowledgment of their marital status or widowhood can be a pathway to regain their marginalized right to social life. To elucidate this issue, we analyzed six representative cases from the tragic October 3, 2013, shipwreck near the Italian island of Lampedusa, where 366 individuals were retrieved dead from the sea. These cases underscore the practical challenges involved, highlighting the compelling need for continued efforts to ensure that this burdensome problem transcends from being a mere ethical, moral, and legal discourse. Although considerable progresses, these cases also reveal that substantial work still lies ahead. There is a pressing need for improved mechanisms to certify kinship ties, which are often the limiting factor in many reunifications, and can hinder the granting of custody to children. The severity and far-reaching implications of this problem necessitate thoughtful attention and action, especially considering the ongoing escalation in migration and related fatalities.

Training in Skull Base Endonasal Endoscopic Surgery: Development and Validation of a Novel Low-Cost Simulation with Animal Cadaveric Model.

BACKGROUND: Endoscopic skull base surgery is constantly evolving and its scope has expanded. The acquisition of surgical skills involves a long learning curve with significant risks for the patient. Therefore, training in the laboratory has become essential to achieve appropriate proficiency and reduce the morbidity and mortality associated with these procedures. The objective of our work is to develop and validate a cost-effective and easily replicable simulator for endonasal endoscopy training using a swine cadaveric model. METHODS: We used fresh Pietrain swine heads. Training exercises of increasing complexity were performed. A Specific Technical Skills and Knowledge Scale was created considering the objectives to be assessed in each task. After the simulation, the trainees were required to answer a satisfaction survey. RESULTS: Ten participants were recruited (5 neurosurgery residents and 5 neurosurgeons). The simulator assessment showed statistically significant differences between groups. Performance was better among the group with endoscopic surgery experience. Face validity was assessed through a postsimulation questionnaire showing an overall mean score of 28.7 out of 30, indicating a highly positive overall assessment of the simulator. Furthermore, 100% of the trainees believe that including endoscopy training in their education would be beneficial. CONCLUSIONS: The endonasal endoscopy training simulator using a swine cadaveric model is a useful and accessible tool for enhancing surgical skills in this field. It provides an opportunity for training outside the operating room, reducing the potential risks associated with patient practice, and improving the training of residents.

Arthroscopic assessment for lateral collateral ligament complex deficiency of the elbow: a cadaveric study.

PURPOSE: To evaluate whether elbow instability due to lateral collateral ligament complex injury can be assessed reliably through arthroscopy. METHODS: Eight fresh human cadaveric elbows were placed in a simulated lateral decubitus position. The radiocapitellar joint (RCJ) gap and ulnohumeral joint (UHJ) gap (mm) were measured with different sizes of probes from the posterolateral viewing portal. The elbow was 90 degrees flexed with neutral forearm rotation for RCJ gap measurement and 30 degrees flexed with full supination for UHJ gap measurement. Sequential testing was performed from Stage 0 to Stage 3 (Stage 0: intact; Stage 1: the release of the anterior 1/3 LCL complex; Stage 2: the release of the anterior two thirds of the LCL complex; and Stage 3: the release of the entire LCL complex) on each specimen. The mean gap of RCJ and lateral UHJ was used for the comparison between stages with the intact elbow. RESULTS: The mean RCJ gap distance in Stage 2 and Stage 3 was significantly increased compared to that in Stage 0 (Stage 0 vs. Stage 2: P = .008; Stage 0 vs. Stage 3: P = .010). The mean UHJ gap distance of Stage 1, Stage 2, and Stage 3 was significantly increased compared to that in Stage 0 (Stage 0 vs. Stage 1: P = 0.025; Stage 0 vs. Stage 2: P = .010; Stage 0 vs. Stage 3: P = .011). In contrast, the release of the anterior 1/3 of the LCL complex (Stage 1) was not significantly increased compared to the mean joint gap distance of RCJ (P = .157). CONCLUSION: Arthroscopic measurement of joint gap widening in RCJ and UHJ is a reliable assessment method to detect LCL complex deficiency that involves the anterior two thirds or more.

Cadaveric Assessment of the Butterfly Graft in Rhinoplasty.

INTRODUCTION: The rhinoplasty butterfly graft is used to improve the internal nasal valve (INV), but post-operative visibility remains a concern. Intraoperative techniques have developed to thin the graft with unknown effect on functionality. OBJECTIVES: Improve understanding of how to modify the aesthetics of the butterfly graft without impacting patient outcomes. Determine how graft contouring affects its biomechanical properties. METHODS: Cadaveric cartilage grafts were used to examine the biomechanics in its native state and with progressive thinning. The force needed to stabilize the INV in an unaltered state and the resistance force provided by native (original), partially thinned, and fully thinned cartilage grafts were recorded. RESULTS: The mean thickness of grafts in their natural state was 1.64 mm, median 1.50 mm (SD 0.64 mm). The fully-thinned mean was 0.84 mm, median 0.8 mm (SD 0.18 mm). The mean force (N) of the native graft was 0.74 N and 0.60 N for fully thin (p = 0.016, 95%). The mean force (N) needed to stabilize the INV was 0.15 N (right) and 0.19 N (left). CONCLUSION: Butterfly grafts can be thinned by approximately 50% of their original thickness and retain the strength to stabilize the INV. LEVEL OF EVIDENCE: NA Laryngoscope, 134:1638-1641, 2024.

Improving alignment in total knee arthroplasty: a cadaveric assessment of a surgical navigation tool with computed tomography imaging.

PURPOSE: To investigate the accuracy of an imageless, optical surgical navigation tool to assist with femoral and tibial bone cuts performed during TKA. PATIENTS AND METHODS: Six board-certified orthopedic surgeons participated in a laboratory cadaver investigation, performing femoral and tibial bone cuts with the assistance of a computer navigation tool. Femoral and tibial varus/valgus, tibial slope, femoral flexion, and both femoral and tibial rotation measurements from the device were compared with angular measurements calculated from computed tomography (CT) images of the knees. RESULTS: Measurements with the navigation tool were highly correlated with those obtained from CT scans in all three axes. For the distal femoral cut, the absolute mean difference in varus/valgus was 0.83° (SD 0.46°, r = 0.76), femoral flexion was 1.91° (SD 1.16°, r = 0.85), and femoral rotation was 1.29° (SD 1.01°, r = 0.88) relative to Whiteside's line and 0.97° (SD 0.56°, r = 0.81) relative to the posterior condylar axis. For the tibia, the absolute mean difference in varus/valgus was 1.08° (SD 0.64°, r = 0.85), posterior slope was 2.78° (SD 1.40°, r = 0.60), and rotation relative to the anteroposterior axis (posterior cruciate ligament to the medial third of the tibial tuberosity) was 2.98° (SD 2.54°, r = 0.79). CONCLUSION: Utilization of an imageless navigation tool may aid surgeons in accurately performing and monitoring femoral and tibial bone cuts, and implant rotation in TKA and thus, more accurately align TKA components.

Assessment of infraorbital foramen position using computed tomography-scan in a cohort of Cameroonian adults: landmarks in facial surgery and anesthesiology.

Introduction: the infraorbital foramen (IOF) is a hole located in the maxillary bone and delivering passage to the infra orbital vascular-nervous bundle. It is an essential structure in the management of orofacial pathologies. Its precise location allows optimal anesthesia of the infraorbital nerve during cleft lip and palate surgery or alcoholization during the management of essential V2 neuralgia. The aim of our research was to determine the morphology and morphometry of the infraorbital foramen in a sample of the Cameroonian population. Methods: we included 208 CT-scans of patients meeting our search criteria. We determined the shape of the IOF and evaluated the transverse and vertical diameters of the IOF. We assessed the distance of the IOF from the maxillary alveolar crest and the infraorbital margin. The Student test was used to determine the association between different variables. The P-value of 0.05 was considered significant and the confidence interval was 95%. Results: male subjects represented 52.4% (n=109) of our participants and the mean age of our population was 26 years ± 7.3. The mean transverse diameter of the left IOF was 1.97 mm ± 0.51 while 1.78 mm ± 0.53. The IOF was more often medial to the lateral palpebral commissure-nasal wing line on the left and right (78.8% and 72.6%, respectively). Our sample showed that in 54.6% (n=113) of subjects, the IOF was oval on the left side, whereas on the right side, the IOF was oval in 52.3% (n=109) of patients. Conclusion: our study showed that to locate the IOF in a Cameroonian individual, one must palpate the vestibular mucosa opposite the maxillary first molar. Then, one must follow the line passing over this tooth, the IOF is located at about 7 mm from the infra-orbital border and 16 mm from the lateral nasal wall. We have shown that the IOF is located medial to the line connecting the nasal wing to the external palpebral commissure.

Sensitivity of Model-Based Predictions of Post-TKA Kinematic Behavior to Residual Errors in Ultrasound-Based Knee Collateral Ligament Strain Assessment.

Ultrasound-based ligament strain estimation shows promise in non-invasively assessing knee joint collateral ligament behavior and improving ligament balancing procedures. However, the impact of ultrasound-based strain estimation residual errors on in-silico arthroplasty predictions remains unexplored. We investigated the sensitivity of post-arthroplasty kinematic predictions to ultrasound-based strain estimation errors compared to clinical inaccuracies in implant positioning.Two cadaveric legs were submitted to active squatting, and specimen-specific rigid computer models were formulated. Mechanical properties of the ligament model were optimized to reproduce experimentally obtained tibiofemoral kinematics and loads with minimal error. Resulting remaining errors were comparable to the current state-of-the-art. Ultrasound-derived strain residual errors were then introduced by perturbing lateral collateral ligament (LCL) and medial collateral ligament (MCL) stiffness. Afterwards, the implant position was perturbed to match with the current clinical inaccuracies reported in the literature. Finally, the impact on simulated post-arthroplasty tibiofemoral kinematics was compared for both perturbation scenarios. Ultrasound-based errors minimally affected kinematic outcomes (mean differences < 0.73° in rotations, 0.1 mm in translations). Greatest differences occurred in external tibial rotations (-0.61° to 0.73° for MCL, -0.28° to 0.27° for LCL). Comparatively, changes in implant position had larger effects, with mean differences up to 1.95° in external tibial rotation and 0.7 mm in mediolateral translation. In conclusion, our study demonstrated that the ultrasound-based assessment of collateral ligament strains has the potential to enhance current computer-based pre-operative knee arthroplasty planning.

Biomechanical Assessment of Bicortical Suspension Device Fixation for Proximal Tibiofibular Joint Instability: Single Versus Double Device.

BACKGROUND: Bicortical suspension device (BCSD) fixation treats proximal tibiofibular joint (PTFJ) instability in both the anterolateral and posteromedial directions. However, biomechanical data are lacking as to whether this technique restores the native stability and strength of the joint. PURPOSE: To test (1) if BCSD fixation restores the native stability and strength and (2) if using 2 devices is needed. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen pairs of fresh-frozen cadaveric specimens were obtained. Six pairs were assigned to the control group and 10 matched pairs assigned for transection to model PTFJ and subsequent BCSD fixation (one specimen with 1-device repair and the other with 2-device repair). Joint stability and strength were assessed by translating the fibular head relative to the fixed tibia either anterolaterally or posteromedially. Control specimens received 20 cycles of 0- to 2.5-mm joint displacement tests (subfailure) and then proceeded to load to failure (5 mm). For the experimental group, cyclic tests were repeated after ligament resection and after fixation. Forces and stiffness at 2.5- and 5-mm displacement were recorded for comparisons of joint strength and stability at subfailure and failure loads, respectively. RESULTS: After repair of anterolateral instability, both the single- and double-device fixations successfully restored near-native states, with no significant differences as compared with the intact group for forces at subfailure load (P = .410) or failure load (P = .397). Regarding posteromedial instability, single-device repair did not restore forces to the near-native state at subfailure load (intact: 92.9 N vs single: 37.4 N; P = .001) or failure load (intact: 170.7 N vs single: 70.4 N; P = .024). However, the double-device repair successfully restored near-native posteromedial forces at both subfailure load (P = .066) and failure load (P = .723). CONCLUSION: For treatment of the most common form of PTFJ instability (anterolateral), this cadaveric study suggests that 1 BCSD is sufficient to restore stability and strength. The current biomechanical results also suggest that 2 devices are needed for restoring PTFJ posteromedial stability and strength. Using 2 devices addresses both types of instability and provides more PTFJ posteromedial stability. CLINICAL RELEVANCE: The results suggest that 1 device should be used for treating anterolateral instability and 2 devices used for posteromedial instability based on the biomechanical study.

Assessment of micromotion at the bone-bone interface after coracoid and scapular-spine bone-block augmentation for the reconstruction of critical anterior glenoid bone loss-a biomechanical cadaver study.

BACKGROUND: Glenoid bone loss is among the most important risk factors for recurrent anterior shoulder instability, and a bony reconstruction is recommended in cases of critical bone loss (> 15%). The commonly used surgical techniques, including coracoid transfer, are associated with considerable complications. The aim of this study was to assess the motion at the glenoid-bone-block interface after coracoid and spina-scapula bone-block reconstruction of the anterior glenoid. METHODS: Twelve cadaveric shoulders were tested. A 20% bone defect of the anterior glenoid was created, and the specimens were randomly assigned for glenoid augmentation using a coracoid bone block (n = 6) or a scapular spine bone block (n = 6). The glenoid-bone interface was cyclically loaded for 5000 cycles with a force of 170 N. The micromotion was tracked using an optical measurement system (GOM ARMIS) and was evaluated with the GOM Correlate Pro software. RESULTS: The most dominant motion component was medial irreversible displacement for the spina-scapula (1.87 mm; SD: 1.11 mm) and coracoid bone blocks (0.91 mm; SD: 0.29 mm) (n.s.). The most medial irreversible displacement took place during the first nine cycles. The inferior reversible displacement was significantly greater for spina-scapula bone blocks (0.28 mm, SD: 0.16 mm) compared to coracoid bone blocks (0.06 mm, SD: 0.10 mm) (p = 0.02). CONCLUSIONS: The medial irreversible displacement is the dominant motion component in a bone-block reconstruction after a critical bone loss of the anterior glenoid. The spina-scapula and coracoid bone blocks are comparable in terms of primary stability and extent of motion. Thus, spina-scapula bone blocks may serve as alternatives in bony glenoid reconstruction from a biomechanical point of view.