At-risk Structures Research Articles

Analysis of the milling response of an artificial temporal bone developed for otologic surgery in comparison with human cadaveric samples

Temporal-bone milling is a delicate process commonly performed during otologic surgery to gain access to the middle and inner ear structures. Because of the numerous at-risk structures of this anatomic area, extensive surgeon training is required. Artificial temporal bones offer an interesting alternative to cadaveric training. However, the evaluation of such simulators has not been systematic, with an absence of objective validation of their milling response, especially in a surgical context.By measuring the milling forces obtained during the classical steps of otologic surgery on six 3D-printed and three cadaveric temporal bones, this work aims at evaluating the ability of the OTOtwin® synthetic temporal bone to reproduce human bone behavior.A better repeatability was obtained for artificial bones than for cadaveric ones. However, the level of forces recorded during artificial bone milling was close to the one measured with cadaveric samples. The effects of both surgical phase and irrigation on milling force levels were also quantified. The experiments conducted in this study confirmed the suitability of OTOtwin® temporal bone model for both otologic surgery training and research purposes. Valuable insights were also gained from this study regarding the understanding of the otologic milling process.

Pleomorphic hyalinizing angiectatic tumor originating in the nasal cavity: A CARE case report

IntroductionPleomorphic hyalinizing angiectatic tumor (PHAT) is a rare low-grade malignant mesenchymal neoplasm. It commonly occurs in the limbs and trunk, with limited occurrences in the head and neck region. Only five cases of PHAT occurring in the head and neck have been reported in the literature to date. The etiology of PHAT remains unclear. We described a case of nasal cavity PHAT following CARE guidelines. Case summaryA 32-year-old male with PHAT originating in the nasal cavity recurred after two surgeries. Adjuvant radiotherapy was performed after the third surgery. The patient has been regularly followed up for 36months, and no tumor recurrence or metastasis has been observed. DiscussionPHAT is a rare soft tissue tumor known for its local aggressiveness. Because of a high risk of recurrence, extensive resection should be implemented, possibly completed by radiotherapy if resection cannot be complete because of proximity to at-risk structures.

3D MONITORING OF COASTAL EROSION CONTROL STRUCTURES USING UAV

Abstract. Coastal erosion has increasingly become a problem in recent years due to rising sea levels caused by global warming. To prevent further coastal erosion and damage, control structures like seawalls and breakwaters have been installed along vulnerable coastlines. However, it is crucial that these structures are regularly and thoroughly inspected for any abnormalities or deformations. At present, inspections are done manually by visual surveys which are time-consuming and inefficient. There is great potential to optimize this process using drone technology equipped with 3D laser scanners. In this study, we utilized a drone with a green laser scanner to inspect and diagnose control structures along the coast. We conducted surveys to determine the basic performance of this approach and used ICP algorithms to extract any deformations in vanishing wave blocks over two time periods. Our results showed high variability in basic performance due to the influence of waves during the surveys. However, we were still able to detect strain of around 50 cm in a submerged breakwater located 3 meters below the water's surface. Furthermore, an overall settlement of approximately 34 cm was observed in the vanishing wave blocks along with some localized movements. This demonstrates that drones can be successfully implemented for efficient inspection, diagnosis and detection of abnormalities and deformations in coastal structures that are extremely difficult to identify through visual surveys alone. The use of this advanced technology will allow for quicker identification of at-risk structures, enabling timely maintenance and prevention of further coastal erosion.

A malignant peripheral nerve-sheath tumor: A CARE case report

IntroductionMalignant peripheral nerve-sheath tumor (MPNST) is an extremely rare sarcoma of the nasal cavity and paranasal sinuses. Non-specific clinical and radiological presentation and challenging histological diagnosis make it little known by physicians. We describe a case of maxillary sinus MPNST, following CARE guidelines. Case reportA 62-year-old woman consulted for swelling of the right cheek and hard palate with several months’ progression. CT and MRI revealed a tissue mass in the right maxillary sinus with osteolysis of the orbital and maxillary floors, hard palate and lateral and medial walls of the maxillary sinus. Biopsy confirmed diagnosis of low-grade MPNST. After total resection and 60Gy adjuvant radiotherapy, 2-year follow-up showed no signs of recurrence. ConclusionMPNST in the nasal cavity and paranasal sinuses is very rare. Because of a high risk of recurrence, wide resection should be implemented, possibly completed by radiotherapy if resection cannot be complete because of proximity to at-risk structures.

Risk factors for moisture damage presence and severity in Finnish homes

Moisture-damaged buildings are a prominent issue in Finland, but with limited information on damage prevalence, degree of severity and risk factors. This paper analyses 14,996 Finnish detached and semidetached houses that have undergone a standardised moisture assessment of interior spaces and at-risk structures inside the building envelope. Confirmed damage (a binary indicator of damage presence) and a damage index (an ordinal indicator of severity) were calculated for each home and their association with different building and area characteristics estimated. Frequently damaged structures include pre-1950s log walls, walls contacting soil, wooden ground floors and false plinths. Around 15% of surveyed houses had risk structure damage, 19% had at least one confirmed damage anywhere in the house and 49% had either confirmed, likely or possible damage. The greatest risk factor for confirmed damage was house age (odds ratio = 1.48 (95% confidence interval (CI) = 1.45–1.51) for each decade since construction), with nearly half of all houses built pre-1939 damaged. Other risk factors explained a third of the effect of building age, and included log external walls, fibreboard roofs, absence of mechanical ventilation, detached properties and wind-driven rain precipitation. Results can support targeted remediation efforts, protect health and estimate exposure–response relationships for moisture damage. Practice relevance Moisture damage in homes causes various health concerns for occupants, and in colder climates such as Finland such damage often occurs within the building structure. This study finds confirmed moisture damage in 19% of surveyed Finnish homes. Most damage was within the building structure, supporting the need for surveys investigating inside known-risk structures. Older homes had much higher damage risk, reflecting different construction methods and ageing, but also suggesting modern building standards are helping to reduce damage. Increased risk in higher wind-driven precipitation regions indicates a need for regulations and research that improve the resilience of all housing to the projected increases in driving rain from climate change. Understanding the building characteristics and structures that increase moisture risk can support targeted remediation and maintenance in vulnerable buildings, conserve older buildings and avoid demolition, and help protect occupant health.

Anterior-To-Psoas Approach Measurements, Feasibility, Non-Neurological Structures at Risk and Influencing Factors: A Bilateral Analysis From L1-L5 Using Computed Tomography Imaging.

Spinal fusion through the anterior-to-psoas (ATP) technique harbors several approach-related risks. We used abdominal computed tomography imaging to analyze the L1-L5 ATP fusion approach measurements, feasibility, degree of obstruction by non-neurological structures, and the influence of patient characteristics on ATP approach dimensions. The vascular window, psoas window, safe window, and incision line anterior and posterior margins for the ATP approach were measured on abdominal computed tomography imaging. The feasibility of approach and the presence of kidneys, ribs, liver, spleen, and iliac crests within the ATP approach were also measured. Correlation and regression models among radiographic measurements and patient age, height, weight, and body mass index (BMI) were analyzed as well as differences in approach measurements based on sex. Safe window and incision line measurements were more accommodating for the left-sided vs right-sided ATP approach. At L4-5, the ATP approach was not feasible 18% of the time on the left side vs 60% of the time on the right side. The spleen was present 22%, 10%, and 3% of the time from L1-4, while the liver was present 56%, 30%, and 9% of the time. The iliac crests were not observed within ATP parameters. Patient age, height, weight, and BMI did not strongly correlate with approach measurements, although ATP dimensions did differ based on sex. This study reports characteristics of the ATP approach including approach measurements, feasibility, non-neurological structures at risk, and influencing factors to approach measurements. While incision line measurements are larger for male patients compared with female patients at the lower lumbar levels, safe window sizes are similar across all levels L1-L5. The kidneys, ribs, spleen, and liver are potential at-risk structures during the ATP approach, although the iliac crests pose limited concern for ATP technique. Patient characteristics such as age, height, weight, and BMI do not markedly affect ATP approach considerations.

Safe femoral tunnel drilling angles avoid injury to the medial and posteromedial femoral anatomic structures during single-bundle posterior cruciate ligament reconstruction with the inside-out technique.

To investigate the relationship between the medial and posteromedial femoral anatomic structures and the femoral tunnel exit produced by different tunnel orientations when creating the femoral tunnel for posterior cruciate ligament reconstruction (PCLR) using the inside-out (IO) technique and to estimate safe tunnel orientations to minimize the risk of iatrogenic injury to these structures. Eleven cadaveric knees were used. The medial and posteromedial aspects of each knee joint were dissected to reveal the "safe zone," which is a bony area that avoids the distribution or attachment of at-risk structures (MCL, PMC structures, and articular cartilage), while remaining 10mm away from the articular cartilage. The hypothesis of this study was that by creating the femoral tunnel at specific angles using the IO technique, the tunnel outlet would be as close to the safe zone as possible, protecting the at-risk structures from damage. Femoral tunnels were drilled at 20 different angle combinations on each specimen: 0°, 15°, 30°, 45°, and 60° relative to a line parallel to the transepicondylar axis in the axial plane, as well as 15°, 30°, 45°, and 60° relative to a line parallel to the femoral axis in the coronal plane. The positional relationship between each tunnel exit and the safe zone was recorded, and the shortest distance between the exit center and the safe zone boundary was measured. The risk of iatrogenic injury differed depending on the drilling orientation (χ2 = 168.880, P < 0.001). Femoral drilling angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/coronal) were considered relatively safer than other orientations (P < 0.05). The shortest distance between the tunnel exit and the safe zone boundary was negatively correlated with the angle in the axial plane (P < 0.001, r = -0.810). When creating the IO femoral tunnel for single-bundle PCL reconstruction, angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/oblique coronal) could be utilized to prevent at-risk structures from being damaged. The drilling angles and the safe zone can be employed to optimize the femoral tunnel in PCLR.

Preclinical Research Platform for Ocular FLASH Irradiation

<h3>Purpose/Objective(s)</h3> Normal tissue sparing effects from FLASH radiotherapy (RT) are potentially transformative for the treatment of ocular cancers. Reducing damage to the abundant at-risk structures within the eye can prospectively increase visual retention rates, relax treatment margins, and eliminate the need for motion tracking by surgically implanted fiducials. To date, no prior work has explored FLASH-RT effects in the context of the eye. In this work, we have conducted a pilot study of x-ray FLASH effects for ocular irradiation in a preclinical mouse model by measuring the functional and pathological changes in healthy eyes following FLASH or conventional (CONV) dose rate irradiation. <h3>Materials/Methods</h3> An immobilization device was designed to enable focal irradiation to a single mouse eye using a FLASH-capable rotating anode x-ray tube. A 5 mm diameter lead collimator was manufactured to encompass the 3 mm target of the entire eye. Dose and dose rate measurements were performed with calibrated radiographic EBT3 films. Cone-beam CTs were acquired of four C57BL6J mice in immobilization to confirm setup reproducibility, quantified by the mean Hausdorff distance between bone segmentations. Healthy 8-week-old C57BL6J mice were irradiated with 150 kVp x-rays to doses of 21 Gy or 34 Gy at FLASH (right eye) and CONV (left eye) dose rates, respectively. Both eyes were irradiated to limit the influence of varying baseline vision between animals in our analysis. Visual acuity was assessed in 3 mice per dose level using scotopic electroretinography (ERG) up to 2 months post irradiation. Histopathological changes were assessed through H&E staining of harvested eyes. <h3>Results</h3> Mouse setup in our immobilization device was highly reproducible, with a mean Hausdorff distance of 0.34 ± 0.10 mm. Measured dose rates within the field were 67.0 ± 1.9 Gy/s and 1.2 ± 0.1 Gy/s at FLASH and CONV settings, respectively. ERGs revealed that FLASH-irradiated eyes at 21 Gy retained visual function up to 2 months post irradiation, while 21 Gy CONV induced blindness at all sampled time points with more severe surrounding skin effects. At 34 Gy, all eyes were blinded within 1 week, with comparable skin toxicities in the irradiated areas regardless of dose rate. Pathological assessment showed a loss of the photoreceptor layer of the retina from CONV irradiation, which remained intact in FLASH-treated mice. <h3>Conclusion</h3> We have developed a novel platform to study x-ray FLASH effects from ocular irradiation in mice. Functional ERG assay revealed a preservation of visual function from 21 Gy at FLASH dose rates that was not present from 21 Gy CONV. Differential damages between FLASH and CONV irradiations were confirmed through histopathology. This first demonstration of FLASH normal tissue sparing effects in a mouse eye model presents a unique and promising translation opportunity for clinical FLASH treatment. Further studies are ongoing to explore the long-term effects of FLASH radiation on vision and its efficacy on intraocular tumors.

Anatomic safe zones for arthroscopic snapping scapula surgery: quantitative anatomy of the superomedial scapula and associated neurovascular structures and the effects of arm positioning on safety.

Neurovascular anatomy has not been previously quantified for the arthroscopic snapping scapula approach with the patient in the most frequent patient position ("chicken-wing" position). The purposes of this study were (1) to determine anatomic relationships of the superomedial scapula and neurovascular structures at risk during arthroscopic surgical treatment of snapping scapula syndrome (SSS), (2) to compare these measurements between the arm in the neutral position and the arm in the chicken-wing position, and (3) to establish safe zones for arthroscopic treatment of SSS. Eight fresh-frozen cadaveric hemi-torsos (mean age, 55.8 years; range, 52-66 years) were dissected to ascertain relevant anatomic structure locations including the (1) spinal accessory nerve, (2) dorsal scapular nerve, and (3) suprascapular nerve. A coordinate measuring device was used to collect data on the relationships of anatomic landmarks and at-risk structures during the surgical approach. The dorsal scapular nerve was a mean of 24.4 mm medial to the superomedial scapula in the neutral position and 33.1 mm medial in the chicken-wing position (P<.001); the dorsal scapular nerve was 21.7 mm medial to the medial border of the scapular spine in the neutral position and 35.5 mm medial in the chicken-wing position (P<.001). The mean distance from the superomedial angle to the spinal accessory nerve intersection at the superior scapular border was 16.5 mm in the neutral position and 15.0 mm in the chicken-wing position (P=.031). The average distance from the superomedial angle to the closest point of the spinal accessory nerve was 11.6 mm and 10.4 mm in the neutral position and chicken-wing position, respectively (P=.039). Neurologic structures around the scapula vary significantly between the neutral arm position and the chicken-wing position commonly used in the arthroscopic treatment of SSS. The chicken-wing position improves safe distances for the dorsal scapular nerve during medial-portal placement and should be considered as a primary position for arthroscopic management of SSS.

Stepwise deep neural network (stepwise-net) for head and neck auto-segmentation on CT images

ObjectiveThe current study aims to propose the auto-segmentation model on CT images of head and neck cancer using a stepwise deep neural network (stepwise-net). Material and methodsSix normal tissue structures in the head and neck region of 3D CT images: Brainstem, optic nerve, parotid glands (left and right), and submandibular glands (left and right) were segmented with deep learning. In addition to a conventional convolutional neural network (CNN) on U-net, a stepwise neural network (stepwise-network) was developed. The stepwise-network was based on 3D FCN. We designed two networks in the stepwise-network. One is identifying the target region for the segmentation with the low-resolution images. Then, the target region is cropped, which used for the input image for the prediction of the segmentation. These were compared with a clinical used atlas-based segmentation. ResultsThe DSCs of the stepwise-net was significantly higher than the atlas-based method for all organ at risk structures. Similarly, the JSCs of the stepwise-net was significantly higher than the atlas-based methods for all organ at risk structures. The Hausdorff distance (HD) was significantly smaller than the atlas-based method for all organ at-risk structures. For the comparison of the stepwise-net and U-net, the stepwise-net had a higher DSC and JSC and a smaller HD than the conventional U-net. ConclusionsWe found that the stepwise-network plays a role is superior to conventional U-net-based and atlas-based segmentation. Our proposed model that is a potentially valuable method for improving the efficiency of head and neck radiotherapy treatment planning.

Surgical advances in the management of brain metastases

As the epidemiological and clinical burden of brain metastases continues to grow, advances in neurosurgical care are imperative. From standard magnetic resonance imaging (MRI) sequences to functional neuroimaging, preoperative workups for metastatic disease allow high-resolution detection of lesions and at-risk structures, facilitating safe and effective surgical planning. Minimally invasive neurosurgical approaches, including keyhole craniotomies and tubular retractors, optimize the preservation of normal parenchyma without compromising extent of resection. Supramarginal surgery has pushed the boundaries of achieving complete removal of metastases without recurrence, especially in eloquent regions when paired with intraoperative neuromonitoring. Brachytherapy has highlighted the potential of locally delivering therapeutic agents to the resection cavity with high rates of local control. Neuronavigation has become a cornerstone of operative workflow, while intraoperative ultrasound (iUS) and intraoperative brain mapping generate real-time renderings of the brain unaffected by brain shift. Endoscopes, exoscopes, and fluorescent-guided surgery enable increasingly high-definition visualizations of metastatic lesions that were previously difficult to achieve. Pushed forward by these multidisciplinary innovations, neurosurgery has never been a safer, more effective treatment for patients with brain metastases.

A novel endoscope-assisted technique for lateral lumbar interbody fusion: feasibility study, technical note, and operative video.

The lateral approach to the spine is generally well tolerated, but reports of debilitating injury to the lumbar plexus, iliac vessels, ureter, and abdominal viscera are increasingly recognized, likely related to the lack of direct visualization of these nearby structures. To minimize this complication profile, the authors describe here a novel, minimally invasive, endoscope-assisted technique for the LLIF and evaluate its clinical feasibility. Seven consecutive endoscope-assisted lateral lumbar interbody fusion (LLIF) procedures by the senior authors were reviewed for the incidence of approach-related complications. One patient had a postoperative approach-related complication. This patient developed transient ipsilateral thigh hip flexion weakness that resolved spontaneously by the 3-month follow-up. No patient experienced visceral, urological, or vascular injury, and no patient sustained a permanent neurological injury related to the procedure. The authors' preliminary experience suggests that this endoscope-assisted LLIF technique may be clinically feasible to mitigate vascular, urological, and visceral injury, especially in patients with previous abdominal surgery, anomalous anatomy, and revision operations. It provides direct visualization of at-risk structures without significant additional operative time. A larger series is needed to determine whether it reduces the incidence of lumbar plexopathy or visceral injury compared with traditional lateral approaches.

You know where you can stick that … or do you? Where to inject the deltoid and why

The COVID-19 pandemic has seen a huge increase in the number of intramuscular injections into the deltoid being administered. Alan Walker provides an overview of the anatomy of the deltoid and injection technique Intramuscular injection into the deltoid muscle is the mainstay of current vaccination practice. The COVID-19 pandemic has seen a huge surge in the number of injections to be administered, and recruitment of vaccinators from more widely differing backgrounds than has been customary. Incorrect technique can cause injury, so this article summarises present knowledge of the at-risk structures, and proposes a method of injection that reduces hazards. It aims to improve the knowledge of vaccinators, and especially their trainers.

Genitourinary complications in orthopaedic surgery

Genitourinary complications following orthopaedic intervention are uncommon but well-described occurrences and exist on a spectrum of severity. These complications vary depending on the anatomic location and surgical approach, with surgery of the spine, hip, and pelvis of particular concern. Injuries to the urinary tract may present acutely with urinary retention or hematuria. However, they often have a delayed presentation with severe complications such as urinary fistula and recurrent infection. Delayed presentations may place the onus of timely and proper diagnosis on the orthopaedic provider, who may serve as the patient’s primary source of long-term follow-up. Detailed knowledge of anatomy and at-risk structures is key to both preventing and identifying injury. Although iatrogenic injury is not always avoidable, early identification can help to facilitate timely evaluation and management to prevent long-term complications such as bladder dysfunction, obstructive renal injury, sexual dysfunction, and chronic pain. Keywords: urologic injury, bladder injury, genitourinary injury, hip arthroplasty, pelvic ring injuries, spine surgery

Evaluation of the milling’s response of a new bi-material 3D-printed model of temporal bone used for surgeons’ training

Middle ear surgery requires from the surgeon a high level of expertise because of the very small anatomical parts involved and the proximity of many at-risk structures. To perfectly manage the gest...

Modern Radiotherapy for Pediatric Brain Tumors.

Cancer is a leading cause of death in children with tumors of the central nervous system, the most commonly encountered solid malignancies in this population. Radiotherapy (RT) is an integral part of managing brain tumors, with excellent long-term survival overall. The tumor histology will dictate the volume of tissue requiring treatment and the dose. However, radiation in developing children can yield functional deficits and/or cosmetic defects and carries a risk of second tumors. In particular, children receiving RT are at risk for neurocognitive effects, neuroendocrine dysfunction, hearing loss, vascular anomalies and events, and psychosocial dysfunction. The risk of these late effects is directly correlated with the volume of tissue irradiated and dose delivered and is inversely correlated with age. To limit the risk of developing these late effects, improved conformity of radiation to the target volume has come from adopting a volumetric planning process. Radiation beam characteristics have also evolved to achieve this end, as exemplified through development of intensity modulated photons and the use of protons. Understanding dose limits of critical at-risk structures for different RT modalities is evolving. In this review, we discuss the physical basis of the most common RT modalities used to treat pediatric brain tumors (intensity modulated radiation therapy and proton therapy), the RT planning process, survival outcomes for several common pediatric malignant brain tumor histologies, RT-associated toxicities, and steps taken to mitigate the risk of acute and late effects from treatment.

A New Surface Landmark for Thumb Digital Nerve Bifurcation: A Cadaveric Study

The radial and ulnar thumb digital nerves are critical for tactile sensation and dexterity in the hand. This cadaveric study sought to validate a surface landmark for the bifurcation of the thumb radial digital nerve (RDN) and ulnar digital nerve (UDN). We used 24 fresh-frozen cadaveric specimens for dissections. With the thumb placed in the plane of the palm and fully radially abducted, the index finger metacarpophalangeal joint was flexed to 90°. Then, while keeping the distal interphalangeal joint straight, the proximal interphalangeal joint was flexed until the fingertip contacted the thenar eminence to identify the point of bifurcation. We made a U-shaped incision and identified the bifurcation of the thumb RDN and UDN. The point of bifurcation was measured from the ulnar- and proximal-most aspects of the incision. The bifurcation of the thumb RDN and UDN was consistently identified within the U in 22 of 24 specimens (92%). In 16 specimens, the index RDN was also identified either trifurcating with the thumb RDN and UDN or branching from a common digital nerve of index RDN and thumb UDN. Most bifurcation points were found directly along the ulnar and proximal edge of the incision. Two specimens contained a bifurcation point 2 mm ulnar to the ulnar limb of the U. The bifurcation U is a consistent landmark for the thumb RDN and UDN point of bifurcation. The variable branching patterns in this region confirms the importance of thorough clinical examination with penetrating injuries to the thenar eminence. This surface anatomic landmark for the thumb RDN and UDN bifurcation may aid in preventing iatrogenic injuries during elective procedures and identifying at-risk structures during penetrating injuries to the palm.

Robotic needle insertion during computed tomography fluoroscopy-guided biopsy: prospective first-in-human feasibility trial.

This was a prospective, first-in-human trial to evaluate the feasibility and safety of insertion of biopsy introducer needles with our robot during CT fluoroscopy-guided biopsy in humans. Eligible patients were adults with a lesion ≥ 10mm in an extremity or the trunk requiring pathological diagnosis with CT fluoroscopy-guided biopsy. Patients in whom at-risk structures were located within 10mm of the scheduled needle tract were excluded. Ten patients (4 females and 6 males; mean [range] age, 72 [52-87] years) with lesions (mean [range] maximum diameter, 28 [14-52] mm) in the kidney (n = 4), lung (n = 3), mediastinum (n = 1), adrenal gland (n = 1), and muscle (n = 1) were enrolled. The biopsy procedure involved robotic insertion of a biopsy introducer needle followed by manual acquisition of specimens using a biopsy needle. The patients were followed up for 14days. Feasibility was defined as the distance of ≤ 10mm between needle tip after insertion and the nearest lesion edge on the CT fluoroscopic images. The safety of robotic insertion was evaluated on the basis of machine-related troubles and adverse events according to the Clavien-Dindo classification. Robotic insertion of the introducer needle was feasible in all patients, enabling pathological diagnosis. There was no machine-related trouble. A total of 11 adverse events occurred in 8 patients, including 10 grade I events and 1 grade IIIa event. Insertion of biopsy introducer needles with our robot was feasible at several locations in the human body. • Insertion of biopsy introducer needles with our robot during CT fluoroscopy-guided biopsy was feasible at several locations in the human body.

Endovascular Treatment of Cavernous Sinus Dural Arteriovenous Fistulas via Direct Transorbital Puncture Using Cone-Beam Computed Tomography Image Guidance: Report of 3 Cases

Certain cavernous sinus (CS) dural arteriovenous fistulas (DAVFs) are difficult to access through transarterial or transvenous routes and may necessitate access through direct transorbital puncture of the superior ophthalmic vein (SOV) or the CS. However, to be successful, the accurate design of the puncture route and guidance are crucial. This study aimed to report our preliminary clinical experience using cone-beam computed tomography (CT) with real-time fluoroscopic overlays for image guidance during transorbital needle puncture. Between December 2017 and July 2018, 3 patients with CS DAVFs were treated via a transorbital puncture to establish access to the CS under the guidance of XperGuide planning software either via direct CS puncture or through the SOV. The guidance trajectory was superimposed onto the real-time fluoroscopic image during needle puncture. Once access was established, the CS DAVFs were treated with a combination of liquid embolic materials and coils. Image guidance aided to avoid at-risk structures and treatment resulted in all cases in complete obliteration of the CS DAVFs as verified by control angiography without peri- or postprocedural complications. Endovascular embolization of CS DAVFs via direct transorbital puncture aided by image guidance provided an alternative option when more conventional approaches are deemed not possible.

Stakeholder assessment of coastal risks and mitigation strategies

Perceptions of coastal hazards and risks and support for mitigation strategies among three different stakeholder groups (experts, businesses, and community members) are compared and analyzed in Waikiki, Hawaii. A justification for research on Waikiki, a world renown tourist destination and its relevance to other coastal communities is provided. It is shown that the three groups perceive risks, such as hurricanes, storm surge, erosion, tsunamis, and other natural and man-made hazards, differently which in turn influences support for mitigation strategies such as sea walls, beach nourishment, elevating or relocating at-risk structures and the preferences as to who should pay for risk reduction strategies. Data were analyzed using basic inferential statistics, GLM regression and correspondence analysis. Correspondence analysis is a novel technique for studying the relationships between stakeholder attributes (demographic, political, etc.) and the level of support for coastal interventions. The implications for researchers, engineers and coastal planners working in at-risk coastal communities are described.