Reporting ChAracteristics of cadaver training and sUrgical studies: The CACTUS guidelines

Fresh Frozen Cadavers as a Novel Training Model for Percutaneous Nephrolithotomy (PCNL)

Introduction

This study aimed to evaluate fresh-frozen cadavers (FFC) as a novel model for percutaneous nephrolithotomy (PCNL) training, focusing on ultrasound-guided supine PCNL.

Methods

Sixteen urologists participated in a 2-day course at a tertiary center to assess the utility of an FFC model for ultrasound-guided supine PCNL. After the procedure, the participants completed a 24-question evaluation of the FFC model using a 5-point Likert scale. The questionnaire assessed tissue quality, US imaging, procedural steps, overall experience compared to live patient procedures, and suitability of the model for both basic and advanced supine PCNL training.

Results

The tactile sensation, skin stiffness, and distensibility of the calyces resembled real-life scenarios as the cadavers thawed. Similarly, US quality was worse in frozen cadavers and improved after irrigation with the collection system. Valdivia-Galdakao positioning is considered more difficult than in real life, because of rigor mortis.

Conclusion

FFC demonstrated robust content validity as a training model for PCNL. The model provides a realistic and effective training experience, offering a promising tool for developing critical surgical skills, while minimizing radiation exposure and procedural risks.

Volume of Operative Maneuverability as a New Measurement in Neuroanatomical Research: A Methodological Quantitative Study and Translational Use in the Operating Room

OBJECTIVE

The lack of standardized metrics in neuroanatomical research limits the objective assessment of neurosurgical approaches. We introduce a novel volume-based parameter, the Volume of Operative Maneuverability (VOM), and evaluate its utility in quantifying surgical corridor dimensions.

METHODS

Seven microscopic and endoscopic skull base approaches were performed on 4 embalmed latex-injected human cadaveric specimens. A spatial principal component analysis algorithm converted surgical entry and target areas into ellipses, allowing ellipsoidal-based VOM calculations. Corridor length ("target distance") and a fixed 10 mm distance from the target ("standardized VOM" [sVOM]) were also measured. Feasibility and reproducibility were assessed using three-dimensional photogrammetry, preoperative imaging models, and a clinical case.

RESULTS

Endoscopic endonasal and anterior transmaxillary approaches offered sufficient corridor volume and trajectory distance but created longer, narrower surgical corridors with lower sVOM than transcranial approaches. Conversely, pretemporal-orbitozygomatic and subtemporal corridors showed the highest VOM and sVOM. Illustrative examples confirmed consistent measurement in photogrammetry and preoperative imaging. A clinical case involving a right spheno-cavernous meningioma demonstrated a VOM of 2.328 cm³, sVOM of 0.615 cm³, and a target distance of 18 mm during extradural anterior clinoidectomy.

CONCLUSIONS

VOM provides a quantitative, reproducible metric for assessing surgical maneuverability toward irregular target surfaces, overcoming the limitations of traditional qualitative assessments. Preliminary data support its use in quantitative neuroanatomical research and suggest potential integration into surgical planning and intraoperative data collection.

Biportal Endoscopic TransOrbital and transMaxillary Approach to the Cranio-Orbital Region and Middle Cranial Fossa: A Preliminary Analysis of Maneuverability

BACKGROUND AND OBJECTIVES

Traditional and well-established transcranial approaches to the spheno-orbital region and middle cranial fossa guarantee optimal intracranial exposure, and additional orbital and zygomatic osteotomies provide further control over extracranial components to be resected; however, these techniques come at the cost of additional morbidity. The introduction of minimally invasive endoscopic approaches and the conceptualization of the so-called "multiportal" paradigm might provide an alternative route. This preliminary study investigates the feasibility of the combined Biportal Endoscopic TransOrbital and transMaxillary Approach (bETOMA) approach to the spheno-orbital and middle cranial fossa regions.

METHODS

Using 4 silicon-injected adult cadaver heads (8 sides; 16 approaches), we systematically dissected through superior eyelid ETOA and endoscopic TMA approaches. The analysis focused on pterygopalatine, infratemporal, anterior and middle cranial fossae, Meckel cave, and cavernous sinus access. We evaluated the feasibility of bETOMA using linear distances, angles of attack, and exposure areas. We also introduced volume of operative maneuverability, its standardized derivative (sVOM), target distance, visuo-operative angle, and working zone volume as novel metrics.

RESULTS

The analysis revealed comparable angles of attack between approaches. ETOA and TMA exposure areas were 918.38 ± 223.93 mm 2 and 257.07 ± 86.07 mm 2 , respectively. TMA showed a larger VOM in the greater sphenoid wing, but ETOA offered superior distal maneuverability (sVOM: 5.39 ± 1.94 vs 2.54 ± 0.79 cm 3 ) and closer intracranial space access (27.45 vs 50.83 mm). The combined approaches yielded a mean working zone volume of 13.75 ± 3.73 cm 3 in the spheno-orbital interface.

CONCLUSION

The bETOMA approach provides adequate neurovascular exposure and maneuverability to the spheno-orbital region, infratemporal, and anterior and middle cranial fossae, addressing significant limitations of previously investigated monoportal techniques (ie, optic nerve decompression, hyperostotic bone resection, and infratemporal exposure). This combined minimally invasive approach might help manage lesions harbored within the cranio-orbital interface region invading the extracranial space.

Evaluation of thin-threaded implants primary stability in type IV bone right after maxillary sinus floor elevation: A human cadaver study

PURPOSE

The bone-implant interface plays a crucial role in obtaining sufficient primary stability for dental implants in weak bone supports. The aim of this human cadaver study was to evaluate the primary stability of new thin-threaded implants when placed in type IV bone right after maxillary sinus floor elevation.

MATERIALS AND METHODS

The study followed the CACTUS (ChAracteristics of Cadaver Training and sUrgical Studies) guidelines. Twenty-four edentulous maxillary posterior zones with type IV bone and a residual bone height of 4 mm were selected using computed tomography scans. First, an osteotome sinus floor elevation was performed (C.M.C Tech, IBS IMPLANT, Daejeon, South Korea). Implants with thin threads (MagiCore, IBS IMPLANT, Daejeon, South Korea) were placed simultaneously. Samples were divided into two groups: Group 1 (G1): 11 mm-long implants with an elevation of 8 mm; Group 2 (G2): 7 mm-long implants with an elevation of 4 mm. Primary stability was assessed using resonance frequency analysis (RFA).

RESULTS

The average primary stability values in the mesiodistal (MD) direction were 45.67 ± 3.09 Implant Stability Quotient (ISQ) for G1 and 38.76 ± 16.94 ISQ for G2, and in the buccolingual direction were 43.33 ± 13.23 ISQ for G1 and 38.47 ± 16.14 ISQ for G2.

CONCLUSIONS

The primary stability of the thin-threaded implants was compatible with clinical osseointegration in sinus sites with limited bone contact area in both experimental situations. Clinical studies are needed to confirm these encouraging results.

A comparison of three techniques for the osteosynthesis after minimal invasive osteotomies for hallux valgus

PURPOSE

Third and fourth-generation minimal invasive osteotomies (MIO) for the treatment of hallux valgus (HV) have become popular procedures worldwide with promising results due to the improvement in the fixation method. The tricortical cannulated screw placement remains a complex procedure that is technically challenging and requires a long skill learning curve with high radiation exposure mainly in the form of intensifier shots (IS) required for the MIO fixation. This study aims to compare the number of X-ray IS required using three different techniques for the cannulated guide placement.

METHODS

A retrospective cross-sectional observational and comparative study was conducted to assess the number of X-rays IS required for correct cannulated screw guide placement using three different techniques: traditional perforator, the drill and joystick, and K-wire first techniques.

RESULTS

A total of 53 MIS procedures from thirty-one patients in two different hospitals were included. IS X-rays were 155.1 ± 29.7 in the traditional technique (n = 14), 143.0 ± 43.2 in the drill and joystick technique (n = 22), and 85 ± 18.7 in the K-wires first technique (n = 17), p =  < 0.001 using one-way ANOVA.

CONCLUSIONS

The K-wire first technique statistically significantly decreases X-ray IS numbers p ≤ 0.001. There were no statistically significant differences between the traditional (after osteotomy K-wire placement) and the drill and joystick techniques (p = 0.36).

Percutaneous ultrasound-guided versus open cut-down access to femoral vessels for the placement of a REBOA catheter

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be useful in treating exsanguinating trauma patients. This study seeks to compare rates of success, complications and time required for vascular access between ultrasound-guidance and surgical cut-down for femoral sheath insertion as a prospective observational case control study. Participating clinicians from either trauma surgery or anesthesiology were allocated to surgical cut-down or percutaneous ultrasound-guided puncture on a 1:1 ratio. Time spans to vessel identification, successful puncture, and balloon inflation were recorded. 80 study participants were recruited and allocated to 40 open cut-down approaches and 40 percutaneous ultrasound-guided approaches. REBOA catheter placement was successful in 18/40 cases (45%) using a percutaneous ultrasound guided technique and 33/40 times (83%) using the open cut-down approach (p < 0.001). Median times [in seconds] compared between percutaneous ultrasound-guided puncture and surgical cut-down were 36 (18-73) versus 117(56-213) for vessel visualization (p < 0.001), 136 (97-175) versus 183 (156-219) for vessel puncture (p < 0.001), and 375 (240-600) versus 288 (244-379) for balloon inflation (p = 0.08) overall. Access to femoral vessels for REBOA catheter placement is safer when performed by cut-down and direct visualization but can be performed faster by an ultrasound-guided technique when vessels can be identified clearly and rapidly.

Does a novel 3D printed individualized guiding template based on cutaneous fiducial markers contribute to accurate percutaneous insertion of pelvic screws? A preliminary phantom and cadaver study

BACKGROUND

Most 3D-printed guiding templates require dissection of soft tissues to match the corresponding surfaces of the guiding templates. This study sought to explore the accuracy and acceptability of the novel 3D printed individualized guiding templates based on cutaneous fiducial markers in minimally invasive screw placement for pelvic fractures.

METHODS

The printed template was tested on five high-fidelity biomimetic phantom models of the bony pelvis and its surrounding soft tissues as well as on two fresh frozen cadavers. Four cutaneous fiducial markers were transfixed on each phantom model prior to performing CT scans to reconstruct their 3D models. Personalized templates for guiding screw insertion were designed based on the positions of the fiducial markers and virtually planned target screw channels after scanning, followed by 3D printing of the guide. Phase 1 consisted of five expert surgeons inserting one anterograde supra-pubic screw and one sacroiliac screw percutaneously into each phantom model using the 3D-printed guide. The deviation of screw positions between the pre-operative planned and post-operative actual ones was measured after registering their 3D modelling. A Likert scale questionnaire was completed by the expert surgeons to assess their satisfaction and acceptability with the guiding template. Phase 2 consisted of repeating the same procedures on the fresh frozen cadavers in order to demonstrate face, content and concurrent validity.

RESULTS

In Phase 1, all ten screws were successfully implanted with the assistance of the guiding template. Postoperative CT scans confirmed that all screws were safely positioned within the bony pelvic channels without breaching the far cortex. The mean longitudinal deviation at the bony entry point and screw tip between the pre-operative planned and post-operative actual screw paths were 2.83 ± 0.60 mm and 3.12 ± 0.81 mm respectively, with a mean angular deviation of 1.25 ± 0.41°. Results from the Likert questionnaire indicated a high level of satisfaction for using the guiding template among surgeons. In Phase 2, results were similar to those in Phase 1.

CONCLUSIONS

The 3D-printed guiding template based on cutaneous fiducial markers shows potential for assisting in the accurate insertion of percutaneous screws in the pelvis.

The role of 3D technology in the practical education of congenital coarctation and its treatment-a feasibility pilot study

BACKGROUND

Coarctation of the aorta (CoA) is a congenital disease with an incidence of 4 out of 10,000 live births, therefore proper education of its treatment is essential. Understanding the disease and the wide array of treatment options is often difficult. Additive manufacturing technology can be used to produce 3D printed hands-on surgical training tools (HOSTT), which can be used for the education and practical training of CoA. This study aimed to investigate the effectiveness of a 3D printable HOSTT for the simulation of coarctation surgery, and it' possible role in practical education.

METHODS

Participants were medical students of Semmelweis University between the second and sixth academic year. A virtual 3D model of an aorta with CoA was generated from a computed tomography angiography scan. Each participant received a 3D-printed aorta phantom and performed either one of four surgical treatment modalities. The simulated surgeries included end-to-end anastomosis, end-to-side anastomosis, prosthetic patch, and subclavian flap aortoplasty. Participants provided feedback, evaluating their understanding of the disease and its treatment by the four surgical reconstruction modalities on a seven-point Likert scale before and after the sessions.

RESULTS

21 medical students participated in this study. Participants' average rating of their understanding of CoA disease and it treatment options before practical training was 4.62 ± 1.07. After training, their average rating increased to 6.19 ± 1.08, showing statistically significant difference.

CONCLUSIONS

Within this study's limitations, the applied HOSTT, manufactured using 3D printing, was effective for the practical training of CoA's surgical treatment methods for medical students.

Computed tomography-based patient-specific cutting guides used for positioning of the femoral component of implants during unicompartmental knee arthroplasty: a cadaver study

BACKGROUND

To investigate whether patient-specific instrumentation (PSI) improves the femoral component positioning of implants during unicompartmental knee arthroplasty (UKA) using cadaver bone models.

METHODS

Fifty adult cadaveric femoral bone specimens collected from February 2016-2018, were randomized to receive medial UKA with a PSI guide (n = 25) or conventional instrumentation (CI) (n = 25). Standard anteroposterior and lateral view radiographs were obtained postoperatively to assess the coronal and sagittal positioning of the femoral prostheses, respectively. The osteotomy time was recorded to assess the convenience of PSI in guiding osteotomy.

RESULTS

Osteotomy time significantly shortened in the PSI group (3.12 ± 0.65 versus 4.33 ± 0.73 min, p < 0.001). There was a significant difference in the postoperative coronal alignment of the femoral component between the PSI and CI groups (varus/valgus angle: 1.43 ± 0.93° vs. 2.65 ± 1.50°, p = 0.001). The prevalence of outliers in coronal alignment was lower in the PSI than the CI group (2/25, 8% vs. 9/25, 36%). Sagittal posterior slope angle of the femoral component was significantly different between the two groups (8.80 ± 0.65° and 6.29 ± 1.88° in the CI and PSI groups, respectively, p < 0.001). The malalignment rate of the femoral component in the sagittal plane was 60% in the CI group, whereas no positioning deviation was observed in the PSI group.

CONCLUSION

This study used a cadaver model to support the fact that CT-based PSI shows an advantage over CI in optimizing implant positioning for UKAs.

Anatomical investigation of the pelvic urogenital fascia in 10 formalin-fixed female cadavers: novel insights into the laparoscopic total mesometrial resection

PURPOSE

Previous anatomical studies of the urogenital fascia (UGF) have focused on males, and there is a lack of relevant anatomical studies on the distribution of the extraperitoneal UGF in females.

METHODS

In this investigation, guided by the embryonic development of the female urogenital system, the ventral pelvic fascia structure of 10 female cadavers was dissected, and the distribution and morphology of female extraperitoneal UGF were observed, recorded in text, photographs and video, and 3D modeling was performed.

RESULTS

We find that in the female extraperitoneal space there is a migratory fascial structure, the UGF, which surrounds the urogenital system and extends from the perinephric region to the pelvis along with the development of the urogenital organs. The two layers of the UGF are composed of loose connective tissue rich in fat that surrounds the urogenital organs, their accessory vascular structures, and the nerves of the abdominopelvic cavity. In the pelvis, it participates in the formation of the ligamentous structures around the rectum and uterus. Finally, it surrounds the bladder and gradually moves into the loose connective tissue of the medial umbilical fold.

CONCLUSIONS

Sorting out the distribution characteristics of UGF has some reference value for studying the metastasis of gynecological tumors, the biomechanical structure of the female pelvis, and the surgical methods of gynecology, colorectal surgery, and hernia surgery.

Thermal Analysis of an Ultrasonic Aspirator Micro Claw Tool Compared With Standard High-Speed Drilling During Internal Auditory Canal Opening in a Cadaveric Model

BACKGROUND

The ultrasonic aspirator micro claw tool (UAmCT) can be used to remove the bone of the internal auditory canal (IAC) during vestibular schwannoma resection via the retrosigmoid approach (RSA) without the risk of a spinning drill shaft. However, the thermal profile of the UAmCT during IAC removal has not been reported.

OBJECTIVE

To compare the thermal profile of the UAmCT during access of the IAC to that of a conventional high-speed drill (HSD) and to present an illustrative case of this application.

METHODS

IAC opening via RSA was performed in 5 embalmed cadaveric specimens using the UAmCT with 3, 8, and 15 mL/min irrigation on the left and the HSD at 75 000 revolutions per minute and 0%, 14%, and 22% irrigation on the right. Peak bone surface temperatures were measured 4 times in 20-second intervals, and statistical analyses were performed using SPSS software. An illustrative case of a vestibular schwannoma resected via an RSA using the UAmCT to access the IAC is presented.

RESULTS

The IAC was opened in all 5 specimens using both the UAmCT and HSD without complication. The mean peak bone surface temperatures were significantly lower with the UAmCT compared with the HSD ( P < .001). The UAmCT did not meaningfully prolong the operating time in the illustrative case, and the IAC was accessed without complication.

CONCLUSION

The UAmCT may be a safe and effective alternative to HSD for IAC opening during vestibular schwannoma resection via the RSA. Larger studies under clinical conditions are required to further validate these findings.

The characteristics of the urogenital fascia in the retrorectal space based on male cadaveric dissection and its clinical application

BACKGROUND

The architecture of retrorectal fasciae is complex, as determined by different anatomical concepts. The aim of this study was to examine the anatomical characteristics of the inferomedial extension of the urogenital fascia (UGF) involving the pelvis to explore its relationship with the adjacent fasciae. Furthermore, we have expounded on the clinical application of UGF.

METHOD

For our study, we examined 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. Our department has performed 466 laparoscopic rectal cancer procedures since January 2020. We reviewed the surgical videos involving UGF preservation and analyzed the anatomy of the UGF.

RESULTS

The bilateral hypogastric nerves ran between the visceral and parietal layers of the UGF. The visceral fascia migrated ventrally at the fourth sacral vertebra, which formed the rectosacral fascia together with the fascia propria of the rectum; the parietal layer continually extended to the pelvic diaphragm, terminating at the levator ani muscle. At the third to fourth sacral vertebra level, the two layers constituted the lateral ligaments.

CONCLUSION

The double layers of the UGF are vital structures for comprehending the posterior fascia relationship of the rectum. The upper segment between the fascia propria of the rectum and the visceral layer has no evident nerves or blood vessels and is regarded as the " holy plane" for the operation.

Reaching Consensus for Comprehensive Outcome Measurement After Urethral Stricture Surgery: Development of Study Protocol for Stricture-Fecta Criteria

Urethral stricture disease is a very heterogeneous condition where different urethral segments can be involved as a result of diverse etiologies which come with variable prognosis. The surgical management of urethral strictures, and in particular urethroplasties can result in very diverse outcomes on many levels and, currently, there is absolutely no consensus about what should and what should not be considered a "success" after urethral surgery. In the wake of well-established quality criteria in urologic oncology, such as tri- or pentafecta outcomes, and given the lack of agreement on meaningful outcomes after urethral surgery, we aim to introduce our study protocol as the first step of a multistep research endeavor to reach consensus on comprehensive urethroplasty outcomes within a novel conceptual framework: the "stricture-fecta criteria". The development of stricture-fecta will be based on a Delphi consensus involving some of worldwide most influencing reconstructive urologists.

Organ harvesting as a mandatory training step of all PGY1 and PGY2 surgical residents

To the Editor, Good surgical training is essential for the formation of excellent surgeons, consequently providing the best possible care for our patients in the future. Considering the increase in surgeon shortage over the last two decades (estimated between 14,300 and 23,400 by the year 2032 only in the US), it is important for filling the national health system's needs as well [...].