Smartphone-Based DIY Home Microsurgical Training with 3D Printed Microvascular Clamps and Japanese Noodles.

We have recently incorporated simple modifications of the konjac flour noodle model to enable DIY home microsurgical training by (i) placing a smartphone on a mug to act as a microscope with at least ×3.5-5 magnification, and (ii) rather than cannulating with a 22G needle as described by others, we have found that cannulation with a 23G needle followed by a second pass with an 18G needle will create a lumen (approximately 0.83 mm) without an overly thick and unrealistic "vessel" wall. The current setup, however, did not allow realistic evaluation of anastomotic patency as the noodles became macerated after application of standard microvascular clamps, which also did not facilitate practice of back-wall anastomoses. In order to simulate the actual operative environment as much as possible, we introduced the use of 3D-printed microvascular clamps. These were modified from its previous iteration (suitable for use in silastic and chicken thigh vessels), and video recordings were submitted for internal validation by senior surgeons. A "wet" operative field where the konjac noodle lumen can be distended or collapsed, unlike other nonliving models, was noted by senior surgeons. With the 3D clamps, the noodle could now be flipped over for back-wall anastomosis and allowed patency testing upon completion as it did not become macerated, unlike that from clinical microvascular clamps. The perceived advantages of this model are numerous. Not only does it comply with the 3Rs of simulation-based training, but it can also reduce the associated costs of training by up to a hundred-fold or more when compared to a traditional rat course and potentially be extended to low-middle income countries without routine access to microsurgical training for capacity development. That it can be utilized remotely also bodes well with the current limitations on face-to-face training due to COVID restrictions and lockdowns.

Three-Dimensional Microscopic Surgical Videos: A Novel and Low-cost System.

INTRODUCTION: Three-dimensional (3D) imaging and videos are a very useful tool in the neurosurgical training, although unfortunately the 3D systems available have a very high cost. The objective of this study is to describe a novel and low-cost 3D microsurgical video system. METHODS: To obtain the 3D videos we use a surgical microscope, 2 video adapters, 2 cameras, and an HDMI cable. A video editor program is used for processing the videos. For the projection we use a computer with PowerPoint (Microsoft, Inc, Redmond, WA) software, a video splitter, DVI cables, 2 projectors, 2 polarization filters, and a "silver screen" with polarized glasses. RESULTS: By using 2 equal cameras and video adaptors in each beam splitter port it was possible for us to obtain 2 videos that were equivalent to the images received by both surgeon's eyes. Using the video signal of both cameras during processing resulted in a 3D stereoscopic recording with Final Cut (Apple, Inc, Cupertino, CA) software. The polarized 3D format provided the best projection conditions. It does not alter the original colors of the videos and its prolonged visualization was more comfortable. The main advantage of this method is the ability to show in a realistic way the spatial relationships and the depth of the structures captured with the microscope. CONCLUSIONS: This paper presents in a clear and detailed way how to create and use a low-cost 3D surgical video system.

Low-Cost Stereoscopic Recordings of Neurologic Surgery Operative Microscopy for Anatomic Laboratory Training.

OBJECTIVE: Stereoscopic video recordings of operative microscopy during neuroanatomic dissections are an important component of surgical training and research in well-financed medical schools and teaching hospitals. However, the high cost of the latest operative microscopes with integrated video recording equipment can be a limiting factor in their worldwide use. The aim of the present work is to provide a simple low-cost 3-dimensional (3D) stereoscopic operative microscope recording system that can be used even in economically and resource-limited locations. This is achieved by using readily available smartphones, smartphone accessories, and computer software. METHODS: Stereoscopic recording is accomplished by attaching and aligning matched or similar smartphones to the eyepieces of an operative microscope using readily available smartphone mounting connectors. Video recordings from the smartphones are then transferred to a personal computer and processed with a video-editing software to generate stereoscopic movies that are viewed on a smartphone using virtual-reality glasses. RESULTS: The setup time to mount and align the smartphone cameras typically requires 15-30 minutes. Video image quality and 3D depth presentation is more than sufficient for surgical training and research purposes. The implementation cost ranges from $1,315-$7,066, or much less if smartphones and a computer are already available. CONCLUSIONS: The 3D video system demonstrated herein can be implemented on any type of operative microscope, including older units for which commercial stereo recording systems are not available. The system and method presented herein can be readily and affordably implemented in low-budget environments for clinical training and research.

Clinical Utility of Intraoperative Tympanomastoidectomy Assessment Using a Surgical Microscope Integrated with an Optical Coherence Tomography.

Significant technical and optical advances are required for intraoperative optical coherence tomography (OCT) to be utilized during otological surgeries. Integrating OCT with surgical microscopy makes it possible to evaluate soft tissue in real-time and at a high resolution. Herein, we describe an augmented-reality, intraoperative OCT/microscope system with an extended working distance of 280 mm, providing more space for surgical manipulation than conventional techniques. We initially performed ex vivo experiments to evaluate system performance. In addition, we validated the system by performing preliminary clinical assessments of tympanomastoidectomy outcomes in six patients with chronic otitis media. The system evaluated residual inflammation in the region-of-interest of the mastoid bone. Most importantly, the system intraoperatively revealed the connection between the graft and the remnant tympanic membrane. The extended working distance allows otological surgeons to evaluate the status of both the mastoid bone and tympanic membrane during manipulation, affording full intraoperative imaging.

Economic Comparison of Hand-Sutured and Coupler-Assisted Microvascular Anastomoses.

BACKGROUND: Compared with hand-sewn anastomoses, microvascular anastomotic coupling devices (MACDs) provide equivalent flap survival and reduced operative time. To date, an economic analysis of MACDs has not been reported. The objective of this study was to evaluate the economics of a venous anastomosis performed using a coupling device compared with a hand-sewn anastomosis. METHODS: Economics were modeled for a single free tissue transfer (FTT) requiring one venous anastomosis performed with either hand-sewn sutures or with a coupler-assisted anastomosis using the GEM COUPLER. Fixed and variable costs incurred with each anastomotic technique were identified with an activity-based cost analysis. Price lists were retrieved from suppliers to quantify disposable costs and capital expenditures. Two literature reviews were executed to identify microsurgical operating room (OR) costs and operating time reductions with coupler-assisted anastomoses. RESULTS: For each venous anastomosis, the use of the anastomotic coupler increased disposable costs by $284.40 compared with a hand-sutured anastomosis. Total fixed and variable OR costs were $30.82 per minute. Operating time was reduced by a mean of 16.9 minutes with a coupler-assisted anastomosis, decreasing OR costs by $519.29. Total savings of $234.89 were generated for each coupler-assisted anastomosis, recuperating the device's capital expenditure after 13 uses. CONCLUSION: Compared with a hand-sewn venous anastomosis, an MACD produces savings with each case and quickly recoups the device's capital expenditure. Despite its limitations and simplicity, this study provides a practical economic analysis that can help inform purchasing decisions, particularly for smaller volume centers where the economic rationale may be less clear.

Technical Assessment of Connector-Assisted Nerve Repair.

PURPOSE: Clinical outcomes of nerve repair have not substantially improved over the last several decades. Although clearly a multifactorial problem, basic principles including proper fascicular alignment are not always realized. The use of short conduits as connectors may enhance nerve alignment by entubulating and directing the approximation of nerve ends. METHODS: Ten hand surgeons (5 experienced and 5 inexperienced) performed a series of in vitro human cadaver nerve repairs. Three small-diameter (2 mm), 3 medium-diameter (3-4 mm), and 3 large-diameter (5-6 mm) nerves were repaired (under 10× magnification) utilizing each of 3 techniques: suture-only, connector-only (sutures placed through the ends of the connector), and connector-assisted (alignment sutures at the nerve interface plus connector). Three judges (blinded to who performed the repairs) assessed each repair for fascicular alignment based on predetermined qualitative scales. RESULTS: Across all surgeons, 23 of 30 connector-assisted repairs were judged good or excellent versus 18 of 30 of the suture-only and 13 of 30 of the connector-only repairs. Experienced surgeons in general did better repairs and in particular were more likely to obtain superior alignment for conduit-only repairs (73.3% vs 13.3% good or excellent) and suture-only repairs (73.3% vs 46.7% good or excellent) and were not statistically different for connector-assisted repairs (86.7% vs 66.7% good or excellent) compared with inexperienced surgeons. CONCLUSIONS: In a cadaver nerve model, there was no significant difference in the technical alignment of conduit-assisted repairs between experienced and inexperienced surgeons whereas inexperienced surgeons were more likely to achieve inadequate alignment with suture-only or conduit-only repairs. CLINICAL RELEVANCE: Connector-assisted repairs combining suture-approximation and entubulation may improve the technical alignment of nerve repairs performed, especially by less-experienced surgeons.

Phonomicrosurgery simulation: A low-cost teaching model using easily accessible materials.

OBJECTIVES/HYPOTHESIS: To introduce the use of a new phonomicrosurgical trainer using easily accessible materials, and to establish the effectiveness of the model. STUDY DESIGN: The model uses a grape imbedded in gelatin, a microscope, and microlaryngeal instruments. The study was designed to test baseline differences in training levels, as well as improvement in performance after training with the simulation model. METHODS: Thirty subjects enrolled in the Stanford University School of Medicine otolaryngology training program performed microlaryngeal surgery tasks on a grape. Tasks were designed to model both excision of a vocal fold lesion and vocal fold injection. Anonymized video recordings comparing presimulation and postsimulation training were collected and graded by an expert laryngologist. Both objective comparison of skills and subjective participant surveys were analyzed. RESULTS: Objectively, trainees in all groups made statistically significant improvements across all tested variables, including microscope positioning, creation of a linear incision, elevation of epithelial flaps, excision of a crescent of tissue, vocal fold injection, preservation of remaining tissue, and time to complete all tasks. Subjectively, 100% of participants felt that they had increased comfort with microlaryngeal instruments and decreased intimidation of microlaryngeal surgery after completing the simulation training. This appreciation of skills was most notable and statistically significant in the intern trainees. CONCLUSION: Microlaryngeal surgical simulation is a tool that can be used to train residents to prepare them for phonomicrosurgical procedures at all levels of training. Our low-cost model with accessible materials can be easily duplicated and used to introduce trainees to microlaryngeal surgery or improve skills of more senior trainees. LEVEL OF EVIDENCE: NA Laryngoscope, 126:2528-2533, 2016.

A Cost-Effective Delivery System for FloSeal During Endoscopic and Microscopic Brain Surgery.

OBJECTIVE: To share our experience with a new delivery system for the flowable hemostatic matrix, FloSeal, in endoscopic and microscopic skull base surgery. METHODS: We prospectively analyzed the use of FloSeal with a hemostatic delivery system in transnasal endoscopic and microscopic skull base procedures performed at the authors' institution from January 1, 2015, to June 30, 2015. In all cases the number of aliquots was noted for the entire operation, and the total number of FloSeal ampules of 5 mL was also recorded. RESULTS: Our device allowed controlled application of small amounts (0.5-1 mL) of FloSeal to the site of bleeding. This controlled application resulted not only in increased visibility during its application, but it also reduced the amount of FloSeal required during the procedure. We were able to use 5-10 applications per 5-mL ampule of FloSeal within an individual procedure. No procedure required more than one 5-mL ampule of FloSeal. Therefore, the use of our device results in a reduction of costs. Prior to the use of our device, we were often only able to use 1 vial of 5 ml of material for 1 or 2 applications, especially in transnasal endoscopic procedures when working along a deep corridor. CONCLUSIONS: Our results indicate that our delivery device of FlowSeal can effectively control hemostasis by applying small amounts of FlowSeal to the site of bleeding. This results in increased visibility during hemostasis and a reduction of cost.

A pilot study to assess the construct and face validity of the Northwestern Objective Microanastomosis Assessment Tool.

OBJECT: Microsurgical skills remain an integral component of neurosurgical education. There is a need for an objective scale to assess microsurgical skills. The objective of this study was to assess the face and construct validity of a bench training microanastomosis module and an objective assessment scale, i.e., the Northwestern Objective Microanastomosis Assessment Tool (NOMAT). METHODS: Medical students, neurosurgical residents, and postdoctoral research fellows at Northwestern University were enrolled in the study. Trainees were divided into 3 groups based on microsurgical experience: 1) experienced, 2) exposed, and 3) novices. Each trainee completed two end-to-end microanastomoses using a 1-mm and a 3-mm synthetic vessel. Two cameras were installed to capture procedural footage. One neurosurgeon blindly graded the performance of trainees using both objective and subjective methods to assess construct validity. Two neurosurgeons reviewed the contents of the simulation module to assess face validity. RESULTS: Twenty-one trainees participated in the study, including 6 experienced, 6 exposed, and 9 novices. The mean NOMAT score for experienced trainees on the 1-mm module was 47.3/70 compared with 26.0/70 and 25.8/70 for exposed and novice trainees, respectively (p = 0.02). Using subjective grading, experienced trainees performed significantly better on the 1-mm module (64.2/100) compared with exposed or novice trainees (23.3/100 and 25.0/100, respectively; p = 0.02). No statistical difference between groups was noted for the 3-mm module with both NOMAT and subjective grading. Experienced trainees took less time to perform both tasks compared with the others. CONCLUSIONS: Face and construct validities of the microanastomosis module were established. The scale and the microanastomosis module could help assess the microsurgical skills of neurosurgical trainees and serve as a basis for the creation of a microsurgical curriculum.

Augmented reality in the surgery of cerebral arteriovenous malformations: technique assessment and considerations.

BACKGROUND: Augmented reality technology has been used for intraoperative image guidance through the overlay of virtual images, from preoperative imaging studies, onto the real-world surgical field. Although setups based on augmented reality have been used for various neurosurgical pathologies, very few cases have been reported for the surgery of arteriovenous malformations (AVM). We present our experience with AVM surgery using a system designed for image injection of virtual images into the operating microscope's eyepiece, and discuss why augmented reality may be less appealing in this form of surgery. METHODS: N = 5 patients underwent AVM resection assisted by augmented reality. Virtual three-dimensional models of patients' heads, skulls, AVM nidi, and feeder and drainage vessels were selectively segmented and injected into the microscope's eyepiece for intraoperative image guidance, and their usefulness was assessed in each case. RESULTS: Although the setup helped in performing tailored craniotomies, in guiding dissection and in localizing drainage veins, it did not provide the surgeon with useful information concerning feeder arteries, due to the complexity of AVM angioarchitecture. CONCLUSION: The difficulty in intraoperatively conveying useful information on feeder vessels may make augmented reality a less engaging tool in this form of surgery, and might explain its underrepresentation in the literature. Integrating an AVM's hemodynamic characteristics into the augmented rendering could make it more suited to AVM surgery.

Operability score: an innovative tool for quantitative assessment of operability in comparative studies on surgical anatomy.

OBJECTIVES: Comparative anatomical studies have proved to be invaluable in the evaluation of advantages and drawbacks of single approaches to access established target areas. Approach-related exposed areas do not necessarily represent useful areas when performing surgical manoeuvres. Accordingly the concept of "operability" has recently been introduced as a qualitative assessment of the ability to execute surgical manoeuvres. The authors propose an innovative model for the quantitative assessment of the operability, defined as "operability score" (OS), which can be effectively and easily applied to comparative studies on surgical anatomy. METHODS: A microanatomical study was conducted on six cadaveric heads. RESULTS: Morphometric measurements were collected and operability scores in selected target points of the surgical field were calculated. As illustrative example, the operability score was applied to the extradural subtemporal transzygomatic approach (ESTZ). CONCLUSION: The operability score is effective in grading system of surgical operability, and instruments manipulation capability. It is a useful tool to evaluate, in a single approach, areas that can be exposed, and to quantify how those areas are suitable for surgical manoeuvres.

A novel computerized surgeon-machine interface for robot-assisted laser phonomicrosurgery.

OBJECTIVES/HYPOTHESIS: To introduce a novel computerized surgical system for improved usability, intuitiveness, accuracy, and controllability in robot-assisted laser phonomicrosurgery. STUDY DESIGN: Pilot technology assessment. METHODS: The novel system was developed involving a newly designed motorized laser micromanipulator, a touch-screen display, and a graphics stylus. The system allows the control of a CO2 laser through interaction between the stylus and the live video of the surgical area. This empowers the stylus with the ability to have actual effect on the surgical site. Surgical enhancements afforded by this system were established through a pilot technology assessment using randomized trials comparing its performance with a state-of-the-art laser microsurgery system. Resident surgeons and medical students were chosen as subjects in performing sets of trajectory-following exercises. Image processing-based techniques were used for an objective performance assessment. A System Usability Scale-based questionnaire was used for the qualitative assessment. RESULTS: The computerized interface demonstrated superiority in usability, accuracy, and controllability over the state-of-the-art system. Significant ease of use and learning experienced by the subjects were demonstrated by the usability score assigned to the two compared interfaces: computerized interface = 83.96% versus state-of-the-art = 68.02%. The objective analysis showed a significant enhancement in accuracy and controllability: computerized interface = 90.02% versus state-of-the-art = 75.59%. CONCLUSIONS: The novel system significantly enhances the accuracy, usability, and controllability in laser phonomicrosurgery. The design provides an opportunity to improve the ergonomics and safety of current surgical setups.

Comparison of magnification in primary digital nerve repair: literature review, survey of practice trends, and assessment of 90 cadaveric repairs.

PURPOSE: To review published clinical outcomes and current practice trends and to assess the quality of cadaveric digital nerve repairs using either loupe or microscopic magnification. METHODS: Published clinical outcomes of digital nerve repair accounting for magnification level were reviewed. Members of the American Society for Surgery of the Hand were surveyed regarding their current surgical practices. Ninety cadaveric digital nerve repairs were performed by 9 hand surgeons using loupe or microscopic magnification and evaluated by a visual grading scale. Univariate and multivariate analyses were used to evaluate repairs. RESULTS: We examined 6 publications involving 130 repairs with loupes (4-6×) and 255 repairs with microscopes. Univariate analysis revealed no statistically superior clinical outcomes using high-powered loupes (4-6×) versus microscopic magnification, with no data on lower-magnification loupes more commonly used in practice. Survey data indicated that 52% of hand surgeons use microscopes and 48% use loupes, with 78% using 2.5 to 3.5× magnification. Univariate analysis of the cadaveric repairs demonstrated excellent repairs in 60% of microscope repairs versus 29% of loupe repairs. Multivariate analysis determined that microscopic magnification was 3.9 times more likely than loupes to yield an excellent repair. The surgeon, level of training, repair time, and stitches per repair were not significantly related to an excellent repair. CONCLUSIONS: Our study indicated that microscope use produces superior quality digital nerve repair. Approximately half of hand surgeons use loupes in current practice, mostly at low magnification (2.5-3.5×). In this context, a higher level of magnification may be positively correlated with better clinical outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

Microvascular anastomotic coupler assessment in head and neck reconstruction.

OBJECTIVE: To assess the advantages of using mechanical anastomotic systems in head and neck free tissue transfer. STUDY DESIGN: Case series with chart review. SETTING: A university-based tertiary care center. SUBJECTS AND METHODS: A retrospective review of mechanical venous coupler devices in head and neck reconstruction performed between October 2004 and December 2006. A total of 261 venous anastomoses were performed in 234 consecutive patients. Five types of flaps were performed: radial forearm (66%), anterior lateral thigh (12%), fibula (9%), rectus abdominis (8%), and latissimus dorsi (2%). Demographic data were collected, and the outcomes measured were flap survival and microvascular complications. RESULTS: The size of the venous anastomosis ranged from 1.5 to 4.0 mm, with most being 3.0 mm (56%) followed by 3.5 mm (23%). The most common recipient vein used was a stump off the internal jugular vein (76%) followed by the external jugular vein (17%). Microvascular complications occurred in <5% (n = 11) of patients, with >50% of those being arterial insufficiency (n = 7). Total failures occurred in 3% (n = 7) of patients: 1.5% (n = 4) acute failures (<5 days) and 1.5% (n = 3) late failures. Of the acute failures, causes included venous congestion (n = 1) and arterial insufficiencies (n = 3). The venous coupler used in the failures was 3.0 mm in diameter. Free flap failures resulting from arterial insufficiency involved coupling to the external jugular vein, while the remaining free flap failures (n = 4) used the internal jugular vein. CONCLUSION: With an early venous failure rate of 0.38%, mechanical anastomosis is an adequate alternative to hand-sewn techniques.

Assessment of the utility of the 2-µ thulium laser in surgical removal of intracranial meningiomas.

BACKGROUND AND OBJECTIVE: Since the 1960s, lasers have been used in neurosurgery for surgical removal of intracranial tumors. Because of its limited penetration (2 mm) through tissues and its wavelength, which is useful in water medium, the 2-µ thulium laser has been applied primarily in urology. Its features are attractive for application under microscope magnification during neurosurgical procedures. The aim of this study was to evaluate the usefulness of the 2-µ thulium laser during microsurgical removal of intracranial meningiomas. MATERIALS AND METHODS: Twenty patients with a diagnosis of intracranial meningiomas were treated with surgical intervention using a 2-µ thulium laser together with bipolar forceps, cavitron ultrasonic surgical aspirator (CUSA) and traditional microdissection instruments. Surgical removal was divided in four phases: (1) dissection from the external structures; (2) coagulation and debulking; (3) dissection from the deep structures; and (4) coagulation and removal of the basal implant. During all these steps, we evaluated the percentage of usage of the 2-µ thulium laser comparing them with bipolar forceps and ultrasonic aspirator and blunt dissection. RESULTS: Thulium laser was used mainly during phases 2 and 4 for 43% and 48.7% of the total removal, respectively. Although also useful during phases 1 and 3, it was only used for 2.2% and 31.3%, respectively: traditional dissection with scissors and forceps was preferred. CONCLUSIONS: Thulium laser seems to be a useful aid in the surgery of intracranial meningiomas, especially to debulk, shrink, and coagulate the mass and the basal implant.