Radiological relationship of the ethmoid slit with the frontal sinus and the anterior ethmoidal artery and applications to the frontal sinus drillout.

PURPOSE: To compare two types of CT acquisition parameters: CT scan of the facial bone and CT scan of the sinuses, for studying the ethmoidal slit and its relationship with the frontal sinus and anterior ethmoidal artery. MATERIALS AND METHODS: Retrospective study of 145 scans of the sinuses and 79 of the facial bones performed between 2012 and 2016. On each scan, the visibility of the ethmoidal slits, their length, their distance from the ethmoidal artery, and their relationship with the anterior and posterior wall of the frontal sinus were studied. RESULTS: The ethmoidal slit was better visualized on CT scans of the facial bone (58.2%) than on those of the sinuses (43.1%) (p = 0.02). The distance between the anterior ethmoidal artery and the anterior part of the cribriform plate was 9.3 mm for CT scans of the facial bone and 8.4 mm for CT scans of the sinuses. The theoretical risk of damaging the glabellar soft tissue and that of damaging the meninges during a frontal sinusotomy was evaluated, respectively, at 9.6% and 26.1% for CT scans of the facial bone, and at 6.2% and 21.5% for sinus scans. CONCLUSIONS: CT scans of the facial bone are better than CT scans of the sinuses for identifying ethmoidal slits and their distance from the canal of the anterior ethmoidal artery. The identification of these elements is relevant for the surgeon during frontal sinus surgery and makes it possible to assess the risk of damaging the glabellar soft tissue or meninges. Performing a CT scan of the facial bone seems preferable to that of a CT scan of the sinuses in certain pathological situations, such as cerebrospinal rhinorrhea or revision surgeries of the frontal sinus.

The advantages of modified Thiel technique in head and neck surgical anatomy teaching.

PURPOSE: Thiel's body preservation method allows the donor body to retain color and soft tissue that are similar to those of a living individual. Since its initial description, the technique has not been developed much. Here, we propose a simpler protocol applied to the head and neck, making the technique easier, cheaper, and more accessible to a greater number of medical schools. METHODS: The modified Thiel technique was applied to three heads separated from the body, followed by 6 h of perfusion and 6 weeks of fixation. This technique was compared with formalin (three heads) and freeze (three heads) preservations during academic training in head and neck surgery. Anatomical dissections included a parotid gland dissection, a submandibular gland dissection, an otologic and an endonasal dissection. Twelve surgeons blindly assessed the three types of preservations using a standardized questionnaire. RESULTS: The modified Thiel technique made possible better quality of dissection and tissue identification, with the exception of endonasal dissection. Concerning the endonasal dissection, the modified Thiel technique ranked best for smell, but all other criteria ranked lower than the freezing method. For the submandibular and parotid gland dissections, the modified Thiel technique was ranked best, with statistically significant differences (p < 0.002) for all items. The modified Thiel technique also ranked significantly better during otologic surgery regarding the quality of the skin/eardrum, bone, and muscle, and the smell. CONCLUSION: This study demonstrated that the modified Thiel technique is an embalming technique which improves the quality of head and neck surgical anatomy education.

New detailed description of the anterior part of the cribriform plate using anatomic specimens and computed tomography.

PURPOSE: Ethmoidal slit (ES) and cribroethmoidal foramen (CF) have been poorly studied, without any radiological description. They may ease cribriform plate's diseases. The objective was to describe the frequency, size, and computed tomography (CT) appearance of these foramina. METHODS: A two-part anatomoradiological study was performed: first on dry skulls using a surgical microscope and CT, second on patients CT scans. For each, foramina were searched for, described, and measured when possible. RESULTS: Thirteen dry macerated skulls were studied. The orbitomeatal plane was relevant for studying ES. With microscope, ES and CF were identified in, respectively, 92% and 100% of cases. Using CT, all ES and CF were visible, with a mean length and width of, respectively, 3.9 ± 1.7 mm and 0.9 ± 0.3 mm for ES and 1.6 ± 1 mm and 0.9 ± 0.3 mm for CF. CT scans from 153 patients were reviewed. ES and CF were identified in, respectively, 80% and 91% of cases, with a mean length and width of, respectively, 3.9 ± 0.8 mm and 0.8 ± 0.2 mm for ES. CONCLUSION: Large-sized ES was found frequently, and were clearly visible in patients CT scans. CF was markedly smaller, but seen in most patient scans. ES and CF could be areas of least resistance in the anterior part of the cribriform plate. CT might be helpful in understanding their pathological implications.

Vestibular-related eye movements in the rat following selective electrical stimulation of the vestibular sensors.

Rats are the most commonly used species in the neurosciences; however, little is known about the effects of selective electrical stimulation of individual vestibular sensors, on their eye movements. This limits their use to study the effects of vestibular stimulation on the brain, and their use in further exploring novel technologies such as artificial vestibular implants. We describe the effects of electrical stimulation of each vestibular sensor on vestibular-related eye movement in rats and compared the results to other species. We demonstrated that each sensor is responsible for specific bilateral eye movements. We found that the eye movements in rats differed from other species. Although the results were similar when stimulating the horizontal canal ampulla, differences appeared when stimulating the vertical canal sensors. During utricular stimulation, the ipsilateral eye moved dorsally in most cases, while the contralateral eye usually moved either caudally, or in extorsion. Saccular stimulation usually moved the ipsilateral eye dorsally or ventrally, while the contralateral eye usually moved ventrally or caudally. This study provides the first data on the application of selective electrical vestibular stimulation in the rat to the study of vestibular-related eye movements.

What vestibular tests to choose in symptomatic patients after a cochlear implant? A systematic review and meta-analysis.

Vestibular function after cochlear implantation is difficult to understand, as subjective vestibular symptoms seem uncorrelated with the results of objective tests. Consequently, clinicians may struggle to decide what assessments to perform for a symptomatic patient. We used a systematic review and meta-analysis approach to enlighten this point. After a study inclusion process, results were classified into four different groups for each test in each study: (1) 'true positive' if the test showed impairment from pre-operative to post-operative in symptomatic patients; (2) 'false positive' if the test showed impairment from pre-operative to post-operative in asymptomatic patients; (3) 'true negative' if the test showed no impairment in asymptomatic patients; and (4) 'false negative' if the test showed no impairment in symptomatic patients. From these groups, sensitivities and specificities of each test were calculated in a meta-analysis. After reviewing more than 3000 references, 16 studies were included, representing 957 patients. The meta-analysis revealed a sensitivity of 0.21 (CI 95 % 0.08-0.40) for the caloric tests, of 0.32 (CI 95 % 0.15-0.54) for the cervical vestibular evoked myogenic potentials (c-VEMP), and of 0.5 (CI 95 % 0.07-0.93) for the head impulse tests. The analysis of prevalence revealed that c-VEMPs were the most often impaired, and the HIT the most often conserved. Our review and meta-analysis revealed that no vestibular test is sensitive enough to be recommended as a single test. Ideally, all the five vestibular sensors should be tested. In clinical practice, we suggest a case-to-case strategy according to patient's symptoms and their suspected origin.

Vestibular function and cochlear implant.

Vestibular lesions are found after cochlear implantation in 23-100 % of cases. The objectives of this study were to evaluate the vestibular function before and after implantation while focusing its feasibility. This prospective study included 35 patients, mean age 49 years. Each patient enjoyed a vestibular balance before and after implantation in a median period of 5 months compared to surgery. Vestibular evaluations were performed using vestibular-evoked myogenic potentials (VEMP) and videonystagmography. Before implantation, the VEMPs were bilateral in 73 % of cases. They are modified after implantation for 13 patients, including 12 missing or reduced potentials on implanted side (p = 0.0015). Caloric tests found themselves a significant decrease in the reflectivity of the ear implanted (p < 0.0001). Vestibular symptoms were independent of changes on vestibular tests. No relation was found between the occurrence of post-operative vestibular symptoms and the results of the vestibular investigations. However, the achievement of these exams is not easy especially for children and only part of the vestibule is tested. In conclusion, the vestibular assessments help to choose the side of implantation, assess the pre-operative vestibular condition and assess and locate vestibular lesions induced. Further tests should enable a complete vestibular assessment.

The forgotten foramina: a study of the anterior cribriform plate.

PURPOSE: The olfactory cleft has garnered interest since the advent of endoscopic skull base surgery. Its precise anatomy, however, is still partially unknown. According to Rouvière, an "ethmoidal foramen" is located in its antero-medial part and contains a process of the dura mater. In a more lateral and anterior location, a second foramen, the "cribroethmoidal foramen", contains the anterior ethmoidal nerve. The aim of this study was to verify the existence of these elements and to establish landmarks for surgery. METHODS: We performed an anatomical and histological study of eight olfactory clefts in four cadavers using both endonasal endoscopic and endocranial dissection. RESULTS: An ethmoidal and a cribroethmoidal foramen were found in, respectively, 100 and 75% of cases. Their mean length was, respectively, 4.1 and 1.8 mm. They were located, respectively, in mean at 5.3 and 5.8 mm from the anterior ethmoidal artery. CONCLUSION: Our anatomical study demonstrates the existence of both foramina. The ethmoidal foramen clearly represents an area of least resistance in the anterior part of the olfactory cleft, which could predispose to anterior skull base cerebrospinal fluid leaks and meningoceles.

Endovascular treatment of symptomatic vestibular aqueduct dehiscence as a result of jugular bulb abnormalities.

A new endovascular treatment consisting of stent-assisted coil implantation is described for jugular bulb abnormalities causing symptomatic vestibular aqueduct dehiscence. Three patients presenting with vertigo associated with pulsatile tinnitus or hearing loss were treated. This technique cured the vertigo and pulsatile tinnitus in all patients and preserved normal cerebral venous drainage with no side effects.

New treatment of vertigo caused by jugular bulb abnormalities.

OBJECTIVE: Jugular bulb abnormalities can induce tinnitus, hearing loss, or vertigo. Vertigo can be very disabling and may need surgical treatments with risk of hearing loss, major bleeding or facial palsy. Hence, we have developed a new treatment for vertigo caused by jugular bulb anomalies, using an endovascular technique. PATIENTS: Three patients presented with severe vertigos mostly induced by high venous pressure. One patient showed downbeat vertical nystagmus during the Valsalva maneuver. The temporal-bone computed tomography scan showed a high rising jugular bulb or a jugular bulb diverticulum with dehiscence and compression of the vestibular aqueduct in all cases. INTERVENTION: We plugged the upper part of the bulb with coils, and we used a stent to maintain the coils and preserving the venous permeability. RESULTS: After 12- to 24-month follow-up, those patients experienced no more vertigo, allowing return to work. The 3-month arteriographs showed good permeability of the sigmoid sinus and jugular bulb through the stent, with complete obstruction of the upper part of the bulb in all cases. CONCLUSION: Disabling vertigo induced by jugular bulb abnormalities can be effectively treated by an endovascular technique. This technique is minimally invasive with a probable greater benefit/risk ratio compare with surgery.

Predictive factors for lateral occult lymph node metastasis in papillary thyroid carcinoma.

Management of lateral no necks in papillary thyroid carcinoma (PTC) is very controversial. The aim of this study was to find predictive factors of lateral neck involvement in N0 PTC to help the clinician in his decision to treat the lateral compartment. We retrospectively analysed 173 patients who underwent thyroidectomy and lateral prophylactic neck dissection for PTC >10 mm. Predictive factors for occult lateral lymph node metastasis including sex, age, tumour size, multifocality and bilaterality, tumour extracapsular spread, vascular invasion and presence of a tumour capsule were examined by multivariate analysis. There were three independent predictive factors for occult lateral lymph node metastases in multivariate analysis: tumour extracapsular spread (p < 0.0001), vascular invasion (p < 0.001) and age <45 years (p < 0.027). When none of these factors was present, the risk of occult metastases was <5 %. The risk increased up to 56 % when at least two of these factors were present. These findings suggest that, in patients older than 45 years with neither tumour extracapsular spread nor vascular invasion on histopathological examination, occult lymph node metastases are very uncommon. In that case further discussion regarding the risks and benefits of lateral nodal dissection may be warranted.

Persistent stapedial arteries in human: from phylogeny to surgical consequences.

The stapedial artery is an embryonic artery which disappears during the tenth week in utero, in human species. During its short life, this artery shapes the stapes and transforms the middle meningeal artery from the internal carotid artery to a branch of the external carotid system. Nevertheless, a persistent stapedial artery is seen in 0.2-4.8 per thousand of human adults. This persistence is usually asymptomatic but can sometimes cause pulsatile tinnitus or conductive hearing loss. Despite the risk of facial palsy, hearing loss and even hemiplegia argued by several authors, some surgeons have succeeded in coagulation without side effects. Reviewing the literature, we seek to enlighten the actual knowledge about the persistent stapedial artery to evaluate the risk to coagulate it. Embryologic studies explain the four types of persistent stapedial arteries: the hyoido-stapedial artery, the pharyngo-stapedial artery, the pharyngo-hyo-stapedial artery and aberrant internal carotid with persistent stapedial artery. Phylogenetic studies show that the stapedial artery persists in adulthood in many vertebrates. Its disappearance is therefore either a random effect or an adaptative convergence. This adaptation could be partially linked to the negative allometry of the stapes. Practically, the risk to coagulate a stapedial artery seems limited thanks to anastomoses, for example with the stylomastoid artery. The risk of hemiplegia reported is in fact an extrapolation of variation in rats' embryos. A persistent stapedial artery can therefore reasonably be coagulated, with special attention to the facial nerve, because the facial canal is always dehiscent where the artery penetrates.

Surgical epidemiology of Antarctic stations from 1904 to 2022: A scoping review.

In Antarctica, it is extremely difficult to organise medical evacuations in winter. Antarctic physicians are often alone and must be prepared to perform surgery and dentistry, even if they are not specialists. This scoping review summarises epidemiological data on the types of surgical procedures performed in Antarctica and identifies gaps in the literature in this area. We searched PubMed and Google Scholar, without language restriction, for papers published between 1 January 1904, and 1 February 2022. Of the 35 papers on 12 Antarctic programs, very few were retrospective observational epidemiological studies; the majority were medical reports. The search identified 41 surgical procedures or reasons for surgical consultation, 19 different reasons for medical evacuations, and 12 causes of death that may have required surgical management. The diagnostic classifications used and the prevalence of each reported surgical speciality were heterogeneous. The most cited specialities were orthopaedics, dentistry, and digestive surgery. Telemedicine was integrated into on-site care or medical evacuation decisions. The current literature is poor, and most studies do not apply to surgical issues. The heterogeneous data collection methodologies limit their interpretation. A standardised diagnostic classification and detailed and systematic epidemiological registers will help define the contours of surgical management in Antarctica.

Surgical training strategies for physicians practicing in an isolated environment: an example from Antarctica. International survey of 13 countries with active winter stations.

For 60 years, human presence in Antarctica has required particularly demanding medical skills. Nevertheless, the preparation of physicians working in this extreme environment remains unknown and deserves clarification. This study aimed to summarise data on the surgical training given to physicians by different countries. In April 2020, we conducted a questionnaire-based study of 14 countries wintering in Antarctica. Responses were descriptively analysed. Regarding the profiles of physicians recruited by the wintering countries, 30% to 55% were non-surgeon doctors compared with 45% to 70% for surgeons depending on the year. Of the 13 countries answering the questionnaire, nine organised practical surgical training and six used theoretical material. All countries reported practical training for dental surgery, while only five countries provided training in four other surgical specialities (orthopaedic, digestive, thoracic, and ear, throat, and nose). All 13 countries reported using a telemedicine system. These results revealed heterogeneous training strategies among the recruited physicians, reflecting the difficulties of practice on this extreme continent. Future work may assess the effectiveness of each strategy. A better understanding of surgical epidemiology and a detailed referencing of the equipment available at the bases would help better define the contours of surgical care in Antarctica.

Occult lymph node metastases increase locoregional recurrence in differentiated thyroid carcinoma.

OBJECTIVES: The impact of occult lymph node metastasis (OLNM) on locoregional recurrence (LRR) and survival in patients with NO differentiated thyroid carcinoma is unclear, because no large study has been carried out. A retrospective study was conducted in our department to assess the influence of OLNM. METHODS: We included 201 patients treated by prophylactic neck dissection for NO differentiated thyroid carcinoma between 1974 and 2006. The incidence of OLNM and predictive factors for recurrence and survival were assessed. RESULTS: The incidence of OLNM was 20%. Necks were involved at levels VI, III, II, IV, V, and I, in decreasing order of frequency. After a mean follow-up of 9 years, the rate of LRR was 8.9% and the rate of distant metastasis was 3.4%. An age of greater than 55 years and the presence of OLNM were predictive factors for LRR. An age of greater than 55 years and the presence of LRR were predictive factors for distant metastasis. The presence of distant metastasis was the only factor that significantly and independently influenced the disease-specific survival. CONCLUSIONS: We found that OLNM occurred in only 20% of NO patients. The presence and especially the number of OLNMs on neck dissection were major risk factors for LRR in this study, but did not affect the disease-specific survival.

Management of total laryngectomy patients over time: from the consultation announcing the diagnosis to long term follow-up.

Throat cancer has always struck people's imagination. This type of cancer affects some of the patient's most essential physiological functions: speaking, swallowing and breathing. At advanced stages, radical surgery is disabling. The impact of a mutilated larynx corresponds to a very real trauma that is both individual and social. Our aim is to define how a total laryngectomy (TL) is represented by both the surgeon and the patient. The history of TL makes it possible to understand the changes that were needed for the key players in the subject to impose or accept this operation. Without doubt, the implementation of the "cancer plan" in the early 2000s was a major turning point in the management of patients with neoplasia. Increased awareness among the elite, encouraged by the mobilisation of patients and their families, is the explanation for the new role played by TL in 2008. The progress made in medical and surgical techniques, modifications to the patient-carer relationship and the appearance of the concept of Quality of Life are all themes that have changed the approach to this operation and the management of patients undergoing a TL.

Motion Sickness Lessons from the Southern Ocean.

BACKGROUND: The objectives were to assess the prevalence, severity, and medication taken, and to look for predictive factors in order to better identify characteristics of passengers at risk of motion sickness during transport from Hobart in Tasmania to the French polar stations in Antarctica. METHODS: There were 239 passengers who were surveyed over 4 yr with 4 round trips per year using the Motion Sickness Susceptibility Questionnaire (MSSQ), Simulator Sickness Questionnaire (SSQ), state-trait anxiety test (STAI-Trait and STAI-State), and general parameters (age, gender, number of trips, jet-lag, direction of the trip), medication, calculation of the distance of each passengers cabin to the center of gravity (CoG). RESULTS: While the passengers had a low intrinsic sensitivity to motion sickness (MSSQ), 94 reported at least one SSQ symptom of motion sickness, and 38 vomited. Five associated factors were discovered: greater initial sensitivity (MSSQ), anticipation of being ill, younger age, higher level of anxiety at midtrip, and greater distance from the CoG. Of the passengers, there were 54 who took anti-motion sickness medication at different times of the trip, however, these passengers experienced more nausea. This could be due to self-selection since they were more sensitive to motion sickness. CONCLUSION: We identified three predictive factors of motion sickness (greater intrinsic susceptibility, younger age, and greater cabin distance from the CoG). For preventive purposes, two associated factors of MS (anticipation of being ill, MSSQ score) were determined to classify three groups of risk of MS to improve passenger care during the trip. Besnard S, Bois J, Hitier M, Vogt J, Laforet P, Golding JF. Motion sickness lessons from the Southern Ocean. Aerosp Med Hum Perform. 2021; 92(9):720727.

Stratification of hippocampal electrophysiological activation evoked by selective electrical stimulation of different angular and linear acceleration sensors in the rat peripheral vestibular system.

It has become well established that vestibular information is important for hippocampal function and spatial memory. However, as yet, relatively little is known about how different kinds of vestibular information are 'represented' in different parts of the hippocampus. This study used selective electrical stimulation of each of the 5 vestibular sensors (the horizontal (HC), anterior (AC) and posterior (PC) semi-circular canals, and the utricle and saccule) in the rat and recorded local field potentials (LFPs) across the hippocampus, using a 16 electrode microarray. We found that stimulation of any vestibular sensor in the left labyrinth evoked triphasic LFPs in both hippocampi, although it was clear that, in general, the amplitudes were greater for the right, contralateral side. This was particularly true for Phase 1 for the HC, AC, utricle and saccule, Phase 2 for the HC, PC, utricle and saccule, and Phase 3 for the AC, PC and saccule. Overall, our results suggest that vestibular input to the hippocampus is bilateral, preferentially contralateral, but highly stratified in that stimulation of the same vestibular sensor results in activation of different specific areas of the hippocampus, with different LFP amplitudes and latencies. This suggests the possibility that different regions of the hippocampus use different kinds of vestibular information for different purposes and that there may be a high degree of redundancy in the representation of vestibular input, perhaps ensuring that the hippocampus is more robust to the partial loss of vestibular information.

Impaired Attentional Processing During Parabolic Flight.

Previous studies suggest that altered gravity levels during parabolic flight maneuvers affect spatial updating. Little is known about the impact of the experimental setting and psychological stressors associated with parabolic flight experiments on attentional processes. To address this gap, we investigated the level of alertness, selective and sustained attention in 1 and 0 g using a Go/No-Go Continuous Performance Task. We also identified several parameters associated with the experimental set-up of a parabolic flight that could be expected to affect attentional processing. These included the use of scopolamine, sleep quality prior to the flight day, participant's stress level as well as mood and anxiety state before and after the parabolic flight. We observed a deterioration in attentional processing prior to the first parabola that was further aggravated in weightlessness and returned to baseline after the last parabola. Reaction Time, Hit and False Alarm Rate were moderately correlated with self-reported anxiety state, but not cortisol levels or emotional states. The use of scopolamine had minor effects on Reaction Time. Our results confirm previous studies reporting impairments of cognitive performance in 0 g, and highlight important aspects that should be considered for the design of behavioral research experiments in future parabolic flight campaigns.