Neutral Neck Research Articles

Ventilation quality and fiber optic glottic view of AuraGain laryngeal mask in neutral, moderate, and extreme lateral head and neck positions in anesthetized spontaneously breathing children

BackgroundWe investigated the effects of moderate (45°), and extreme (60°) right lateral rotation of the head and neck on the ventilatory performance of Ambu AuraGain Laryngeal mask airway in generally anesthetized spontaneously breathing children. MethodsFifty-two children (aged 2–9 years) were randomized in this open-label observational cohort, to receive Ambu® AuraGain either in moderate (45°) (Group I, n = 26) or extreme (60°) (Group II, n = 26) lateral rotation of the head and neck. The oropharyngeal leak pressure OLP (primary outcome), ventilation score, exhaled tidal volume, and fiberoptic glottic view score, were recorded with the head and neck in a neutral position, then in lateral position after insertion by 1,15,30 and 45 min., and at end of surgery. ResultsThe mean OLP in group I decreased from 23.81 ± 2.87 cmH2O in the neutral position to 23.77±3.78 cmH2O, (P = 0.941) 1 min. after lateral rotation. Whereas, In group II, it increased from 20.38 ± 4.18 cmH2O to 21.88±3.28 cmH2O, (P = 0.002). Afterward, the OLP was maintained decreased in group I and increased in group II (P < 0.05), with no intergroup differences. The ventilation score did not show significant intra or inter-group differences. After lateral rotation, the fiberoptic glottic score showed a trend towards better values in group II than in group I. ConclusionVentilation with AuraGain LMA can efficiently be implemented while the head and neck are in the neutral and laterally rotated positions in anesthetized spontaneously breathing children. Extreme lateral rotation (60°) was better tolerated than the moderate position (45°).

Measuring the usability of a novel ergonomic chinrest during violin playing: A feasibility study.

Playing the violin often requires a rotated and lateral flexed neck, leading to potential neck and shoulder problems. An ergonomic chinrest (EC) with or without a shoulder rest (SR or WSR) may enhance neutral neck positioning, but the feasibility of the EC needs to be studied. Our goal was to evaluate the usability of the EC for a two-week familiarisation period, including aspects such as playing performance, comfort level, and emotional response (e.g., feelings about using the product) among a group of violinists. A one-arm feasibility study was conducted to assess the feasibility of violinists playing with EC every day for two weeks. Six violinists who usually played with SR were included and asked to divide their daily playing time equally between SR and WSR. Feasibility outcomes were measured as adherence (days), compliance (playing hours per day) and usability (5-point Likert scale and open-ended questions). Compliance was achieved with a minimum of 25% playing time. Daily violin playing with EC showed high adherence of 89.3%. Compliance with the 25% play time criterion was met for SR, but not for WSR. Low playing performance (median 45.8 points difference), long confidence time (two violinists failed to reach a confidence level) and mainly negative feedback (26 out of 33 comments) were found in WSR compared to SR. The feasibility of playing WSR was low and negatively impacted playing performance. As a result, a larger-scale study will only evaluate the EC with SR due to greater feasibility.

Prevalence of anterior atlantoaxial subluxation and association with established rheumatoid arthritis.

Spinal involvement in rheumatoid arthritis (RA) is limited to the upper cervical spine, leading to cervical spine instability. This study aimed to evaluate the prevalence of anterior atlantoaxial subluxation (aAAS) and its associated risk factors in patients with RA. This single-centre cross-sectional study 240 patients consecutively were recruited. Radiographs of the cervical spine were obtained in the flexion and neutral neck positions and read by two blinded observers. The diagnosis of aAAS was based on the distance between the anterior aspect of the dens and the posterior aspect of the anterior arch of the atlas, which was >3mm during flexion. Statistical analysis was performed to determine the predictive factors of aAAS. Two hundred and forty patients with a mean±SD age of 56.4±11.4years were recruited, and 191 (78%) were female. The mean±SD duration of the disease was 10.2±8.5years. Of all 25 cases (10.4%) diagnosed with aAAS, the mean anterior atlantodental interval in patients with AAS was 4.19±1.20mm. One in three patients with aAAS had no neck pain. Patients with aAAS had longer disease duration, lower age at diagnosis, lower body mass index, higher anti-cyclic citrullinated peptide autoantibodies (anti-CCP), more frequent erosion, joint restriction, and joint prostheses. In the multivariate regression model, joint limitation, history of joint prostheses, low BMI, and higher anti-CCP levels were independent predictors of the aAAS. Thirty-three percent of patients with cervical involvement do not experience neck pain. Cervical involvement should be considered even without neck pain, particularly in established diseases.

Effect of finger rest positions on upper limb muscle activity during pre-clinical procedures.

This study aimed to observe the effect of different finger rest positions on the muscular activity of the hand, forearm, arm, shoulder, thorax, and neck, as well as on the angular deviation from the neutral position of the neck, trunk, upper arm, and forearm on the working side during pre-clinical procedures. An experimental laboratory study was performed. Response variables were muscle activation of the abductor pollicis, brachioradialis, biceps brachii, deltoid, pectoralis major, and right sternocleidomastoid muscles and angular deviation from the neutral position of the neck, trunk, arm, and forearm during simulated clinical procedures. Independent variable was finger-rest position during cavity preparation (no finger rest, usual rest, and ergonomic rest). Class I cavity preparations (N = 120) were performed on artificial first molars (16, 26, 36, and 46) (N = 120). Muscular activation was assessed by surface electromyography and angular deviations using Software for Postural Assessment (SAPO) version 0.69. One-way analysis of variance and Tukey's or Games-Howell's post-hoc tests were performed (α = 0.05). For the sternocleidomastoid muscle, there was no statistically significant difference between the different rest positions. For the deltoid muscle, work with no finger rest resulted in greater muscle activation (p < 0.001) during work on tooth 36. Regarding the pectoralis major and right brachioradialis muscles, we observed that for both teeth 16 and 26, working with ergonomic rest showed less muscle activation. Muscle activation of the right biceps brachii was higher for work with no rest in both the upper and lower arches, differing significantly only from the usual rest in tooth 16 (p < 0.001), usual rest and ergonomic rest in teeth 26 and 46 (p < 0.001), and only ergonomic rest in tooth 36 (p = 0.044). In the right abductor pollicis muscle, work with ergonomic rest resulted in less muscle activation for cavity preparation in teeth 16, 26, and 36, which was significantly different from work with no rest (p = 0.029, p < 0.001, and p = 0.013, respectively). Regarding angular deviation, it was observed that for tooth 16, there was a greater angular deviation of the arm when performing cavity preparations with no finger rest. For teeth 26 and 46, the ergonomic finger rest provided lower angular deviation from the neutral position of the right arm. For tooth 36, ergonomic rest provided less angular deviation from the neutral neck position. In general, the use of non-active finger rest during simulated cavity preparations, regardless of the type of rest, provided less muscle activation and angular deviation from the neutral position of the body's upper extremity when performing pre-clinical procedures.

Commentary: The impact of yoga practice on glaucoma.

Yoga is the most popular form of complementary therapy being practiced to maintain one’s physical and mental wellbeing. While yoga traditionally comprises advice for ethical lifestyle and spiritual practice, it is most often associated with physical postures (asanas), breathing techniques (pranayama), and meditation (dhyana). While these exercises are routinely safe, there are risks involved for certain patients including those suffering from or at risk of glaucoma. The effects of yoga on intraocular pressure (IOP) have been found to be bidirectional, and the exact mechanisms are not yet fully understood. The authors have reviewed literature to study the effect of yoga on IOP and glaucoma. They have observed a reduction of IOP in patients of glaucoma through Jyoti tratak (candle meditation) and slow yoga breathing exercises and a rapid increase in IOP immediately after head-down posture yoga.[1] Tratak kriya is said to lead to contraction and relaxation of ciliary muscles, which may possibly increase the aqueous humor outflow and subsequently decrease the IOP.[2] Dada et al.[3] have evaluated the effect of yoga and meditation on IOP, quality of life, stress markers, neurotrophins, and gene expression in patients with primary open-angle glaucoma and found an improvement in all parameters. On the other hand, progressive glaucomatous optic neuropathy and field loss in patients who regularly practiced Sirsasana (Headstand) has also been identified.[1,4,5] Four yogasanas [Adho Mukha Savasana (downward-facing dog), Uttanasana (standing forward bend), Halasana (plough pose), and Viparita Karani (legs-up-the-wall)] showed a 20–73.7% increase in IOP in all study subjects.[1] Yoga with head-down positions was associated with a rapid rise in IOP in glaucoma and healthy eyes and with the body vertical, with a doubling of the IOP, remaining elevated as long as the position was maintained.[1] Mani Baskaran et al.[6] observed a twofold increase in IOP during Sirsasana, which was maintained during the posture in all age groups irrespective of their ocular characteristics. Valsalva maneuver is known to affect IOP; so it is expected that breath-holding yogic exercises are likely to cause IOP elevation. Forced unilateral nostril breathing has also been observed to affect IOP significantly.[7] Rakstyte et al.[8] studied an impact on IOP before, during, and after Matsyasana (fish yoga pose) and found an increased IOP in head- down position which returns to the initial value shortly after. A case series by Mehrdad Malihi et al.[9] to study the effect of different body and head positions on IOP shows a lower measurement while sitting with a neutral neck position and a rise in IOP in all other positions. Acute angle-closure glaucoma attacks often precipitated by prone-position yoga exercises suggest that this position probably increases pupillary block in “at risk” eyes by causing the lens to fall onto the iris, which has been the principle of the prone provocative test for decades. Certain questions, however, remain unanswered. It is unclear whether yoga has any sustained effects on the IOP and optic nerve. Further research is needed to fully comprehend the mechanisms by which yoga exerts its effects and determine the types, optimal duration, and frequency of yoga practice for glaucoma patients. Future studies are also warranted to ascertain whether yoga-associated IOP changes are associated with parallel changes in perimetry and nerve fiber thickness and changes in cerebrospinal fluid pressure, blood pressure in lamina cribrosa capillaries, and the ocular blood flow. It is difficult to establish direct causality between different yogic postures and glaucomatous progression, but in patients with pre-existing glaucomatous optic neuropathy, dramatic changes in IOP can definitely be harmful. Inquiring about the practice of yoga in cases of unexplained progression despite an apparently well-controlled IOP can, therefore, be an important consideration. Relaxation and meditative aspects of yoga may help to reduce stress and improve the overall well-being of an individual which can be indirectly beneficial. The key is to “keep the head above the heart at all times.” It is also important to note that yoga should not replace traditional glaucoma treatment but rather be practiced/advised as a complementary therapy and glaucoma patients should consult their healthcare provider before beginning any new exercise or relaxation program, including yoga.

A Diagnostic Biomarker for Cervical Myelopathy Based on Dynamic Magnetic Resonance Imaging.

Multicenter prospective observational study. Diffusion tensor imaging in flexion extension improves the diagnosis of degenerative cervical myelopathy (DCM). We aimed to provide an imaging biomarker for the detection of DCM. DCM is the most common form of spinal cord dysfunction in adults; however, imaging surveillance for myelopathy remains poorly characterized. Symptomatic DCM patients were examined in maximum neck flexion-extension and neutral positions in a 3T-magnetic resonance imaging scanner and allocated to 2 groups: (1) Patients with visible intramedullary hyperintensity (IHIS) on T2-weighted imaging (IHIS+, n = 10); and (2) Patients without IHIS (IHIS-, n = 11). Range of motion, space available for the spinal cord, apparent diffusion coefficient (ADC), axial diffusivity (AD), radial diffusivity, and fractional anisotropy were measured and compared between the neck positions and between the groups as well as between control (C2/3) and pathologic segments. Significant differences between the control level (C2/3) and pathologic segments were appreciated for the IHIS+ group at neutral neck position in AD; at flexion in ADC and AD; and at neck extension in ADC, AD, and fractional anisotropy values. For the IHIS- group, significant differences between the control level (C2/3) and pathologic segments were found only for ADC values in neck extension. When comparing diffusion parameters between groups, radial diffusivity was significantly different in all 3 neck positions. Significant increases in ADC values between the control and pathologic segments were found for both groups in neck extension only. This may serve as a diagnostic tool to identify early changes in the spinal cord related to myelopathy to indicate potentially reversible spinal cord injury and support the indication for surgery in select circumstances.

An Optical Intervention to Improve Cycling Time Trials: A Feasibility Study

(1) Background: Many professional and recreational cyclists experience that neck extension in time trial position negatively impacts either speed, comfort, or power production—especially at high cycling speeds or for long distances. We conducted a feasibility study with one subject to assess whether redirecting the sight of a cyclist while in time trial position could reduce aerodynamic drag and neck strain by maintaining a more neutral neck position. (2) Methods: A physical immersive exercise bike was developed (called a FAAST-trainer) that emulates posture, velocity, and power to be delivered by the user through an adaptable power load adjusted in real time. As an optical intervention, we used prism glasses to redirect the cyclist’s sight. The subject trained his perceptive-muscular system while cycling on the FAAST-trainer to get used to wearing prism glasses. He feels confident that the glasses are safe to test for future experiments in a velodrome. (3) Results: A consistent reduction in drag was found (p &lt; 001) when wearing prism glasses with the FAAST-trainer, ranging from 3.5% to 4.7%. Accordingly, the cyclist could thus save between 9.7 watts and 13.0 watts cycling at 45 km/h, compared to having his head in an upright position. (4) Conclusions: Our experiment on the FAAST-trainer indicates that an optical intervention to reduce neck extension by redirecting sight might be safe to use for outdoor cycling. However, no vestibular effects, neither auditive nor complex combinations, were assessed, so we recommend additional research and development of a dedicated design for the prism glasses. Outdoor experiments should be conducted to confirm this reduction in aerodynamic drag and further asses the safety when wearing prism glasses.

Current Trends in Endoscopic Ear Surgery.

Current Trends in Endoscopic Ear Surgery.

Impact of Digital Device Use on Neck and Low Back Pain Intensity among Nursing Students at a Saudi Government University: A Cross-Sectional Study.

As digital technology and online activities have become more widely accessible over the past few years, information and communication technology have grown in importance in all students' lives. Most of them routinely use digital devices for a range of activities, primarily for online learning, activities, assignments, conversing, and Internet browsing. This study elucidated the relationship between neck and low back pain intensity and the use of digital devices among Saudi nursing students. A cross-sectional descriptive exploratory research design was applied using a convenience sample of 120 nursing students enrolled in an undergraduate nursing program at a Saudi government university located in Riyadh, the capital city of Saudi Arabia. A valid and reliable self-administered survey was employed. Data about sociodemographic characteristics, the Neck Disability Index and the Roland-Morris Disability Questionnaire were collected. The participants reported 9.1 ± 4.6 study hours on average per week. A total of 82.5% of them do not receive enough exercise, and 87.5% indicated daily use of digital devices. Around half (54.2%) of participants reported having neck pain of a mild intensity. About 60% of the participants regularly shift positions to rest their backs, 39.2% are only able to stand for limited periods due to back issues, and 39.2% expressed concern for others about what might happen to their health. Although there was an association between neck pain intensity and the age or gender of all research participants, there was a significant association between neck pain severity and marital status (χ2 = 15.226, p = 0.019). Our findings suggest that nursing students should maintain neutral neck and back postures on a regular basis to reduce pain, which could be attributed to extensive reading on digital devices.

Relationship between K-line distance and surgical outcome in cases of laminoplasty for cervical ossification of the posterior longitudinal ligament.

Although previous studies indicate that changes in cervical alignment after laminoplasty and dynamic factors influence surgical outcomes of cervical ossification of the posterior longitudinal ligament (OPLL), the relationship between the surgical outcomes, the distance between the kyphosis-line (K-line) and OPLL, and dynamic factors have not yet been quantitatively evaluated. The purpose of the present study was to analyze the relationship between ΔK-line distance and surgical outcomes in cases of laminoplasty for OPLL of the cervical spine. We retrospectively reviewed 46 consecutive patients (33 men and 13 women) with cervical OPLL who underwent laminoplasty. "K-line distance" was measured as the minimum interval between the K-line and OPLL on lateral radiographs. The following factors were analyzed: K-line distance in neutral, flexion, and extension neck positions, ΔK-line distance, preoperative C2-7 range of motion (ROM), preoperative segmental ROM, preoperative C2-7 lordotic angle, occupying ratio of the OPLL, disease duration, preoperative and postoperative Japanese Orthopaedic Association (JOA) score, and recovery rate. Patients were divided into flexion K-line (+) and flexion K-line (-) groups. We then analyzed the influence of the K-line distance on surgical outcomes and conducted multivariate analysis to analyze the factors affecting surgical outcomes. The JOA score recovery rate in the flexion K-line (-) group was significantly lower than that in the flexion K-line (+) group (P = .024). The ΔK-line distance was significantly negatively correlated with the JOA score recovery rate (r = -0.531, P < .001). Additionally, multivariate analysis showed that ΔK-line distance (OR = -2.143, P = .015) was negatively correlated with the JOA score recovery rate. The ΔK-line distance is considered useful for the quantitative evaluation of dynamic factors and static compression factors due to OPLL through the measurement of dynamic radiographic images.

Preoperative Significance of Ipsilateral Manual Neck Compression in Patients With Pulsatile Tinnitus Secondary to Sigmoid Sinus Dehiscences and Diverticula.

Venous pulsatile tinnitus (PT) is characterized by an auditory perception of pulse-synchronous sound, suppressed by compression of the ipsilateral internal jugular vein. We sought to determine the preoperative prognostic significance of the effect of ipsilateral neck manual compression on the PT loudness and audiometric changes in patients with sigmoid sinus dehiscences (SS-Deh) and diverticula (SS-Div) by comparing postoperative improvements in ipsilateral low-frequency hearing loss (LFHL) in pure-tone audiogram (PTA) and PT symptoms. Twenty-two subjects with PT originating from SS-Deh/Div were recruited. Air-conduction hearing thresholds were measured using PTA at three time points: twice preoperatively (with neutral neck position and with ipsilateral manual compression of internal jugular vein) and once at 3-months postoperatively with neutral neck position. We defined a positive neck compression effect as a threshold improvement of ≥ 10 dB HL at 250 or 500 Hz after manual neck compression. All but two subjects presented with ipsilateral LFHL in the neutral position. The average hearing threshold in the neutral position markedly improved after manual neck compression, indicating that LFHL originated from the masking effect of venous PT. All subjects had subjective improvements in PT and LFHL after sigmoid sinus surgeries, confirming that LFHL resulted from the masking effect of PT. Additionally, improvement of LFHL after neck compression could be regarded as a positive prognostic indicator after surgery. Collectively, elimination of PT loudness and improvement of LFHL with manual compression over the ipsilateral neck may suggest the venous origin of the PT and predict a favorable outcome following repair of SS-Deh/SS-Div.

Pressure injuries in mechanically ventilated COVID-19 patients utlising different prone positioning techniques – A single centre experience

Introduction: Prone positioning (PP) may be utilised to improve oxygenation in mechanically ventilated patients with COVID-19 pneumonia. Pressure injuries (PIs) are a well-recognised complication of prolonged PP. It is unclear how best to position prone patients to minimise this risk. Objectives: To ascertain differences in the incidence and distribution of PIs with two prone positions. Methods: An iterative PP guideline for mechanically ventilated patients was developed in a tertiary intensive care unit during a pandemic surge between September and November 2021. PI data was collected prospectively on all prone patients. A default ‘Face Down’ approach utilised a neutral neck position with face resting on a foam pillow and arms resting by sides. After 3 weeks, this default approach was changed to ‘Swimmer’s Position’ which involved the patient’s head turned to the side, one hand resting next to patient’s face and other arm resting by side with 3-hourly turns. An endotracheal anchoring device was the preferred airway securement technique with both approaches. Results: Fifty-one mechanically ventilated patients had 161 prone episodes during this timeframe. Seven patients had both ‘Face Down’ and ‘Swimmer’s Position’ PP. Of the remaining 44 patients, 34 had ‘Face Down’ PP only. Twenty-six (76%) patients developed 55 PIs – cheek (22), chin (8) and nose (5) were the most common PI areas. Ten patients had ‘Swimmer’s Position’ PP only. Four (40%) patients developed 15 PIs – cheek (4), lip (3) and ear (2) were the most common PI areas. The majority (81%) of all PIs were Stage 1 or 2. No PIs required surgical intervention. Overall, fewer patients had PIs with Swimmer’s Position (OR 0.21, 95% CI 0.05, 0.91). Conclusion: ‘Swimmer’s Position’ yielded a lower overall incidence of PIs than ‘Face Down’ PP. The anatomical distribution of PIs differed for these two prone positions.

A RETROSPECTIVE STUDY ONFUNCTIONAL OUTCOME OF OPERATED INTERTROCHANTERIC FEMUR FRACTURES REDUCEDWITH A POSITIVE BEAK VS NEUTRAL VS NEGATIVE BEAK - AN ARTICLE AND REVIEW OF LITERATURE

Background: Inter-trochanteric fracture is one of the most common fractures in elderly population around the world due to global rise of osteoporosis, which is generally due to a simple slip and fall in the house hold[1]. It is growing to be a disease burden for orthopedics of our era to manage. With its rise Understanding the important factors in management of IT fracture like stability, reduction, role of posterior-medial wall support, intact lateral wall configuration, will help in choosing implant for better outcome ,thus helping to achieve better post operative results[2]. Hence, understanding the role of posteriomedial wall support in IT fracture reduction in terms of positive, neutral(anatomic) or negative beak and its impact on the post operative fracture stability and early ambulation is of great importance. We conducted a retrospective comparative study in our institution to study the outcome of these configuration and its effect post operatively. Methods: A retrospective comparative study was conducted on 60 patients with Intertrochanteric fracture(38 males and 12 females with a mean age of 64.8years) without any associated fractures in elderly population in a time frame between February 2019 to August 2021 using Cephalo-mudullary nailing and Sliding hip screw in our institution. The subject population was graded into 3 groups based on the postero medial cortical wall support in post operative fracture reduction into positive, neutral(anatomic) and negative beak configuration and its effects on post operative fracture stability and early mobilization. Results: In the post operative analysis it was found that the 24 subjects who had positive configuration in the neck shaft angle versus 16 neutral(anatomic) and 10 negative configuration in their neck shaft angle had a superior and better outcome in terms of early ambulation and better long term stability without any statistical differences in terms of age, sex, post traumatic day or any co-morbidities. Conclusion: Thus, we concluded that the fracture reduction with positive reduction achieved a greater stability in terms of early mobilization and better post operative stability and fracture healing than the neutral and negative neck shaft angle. Further it was seen that neutral configuration also had a superior advantage over negative configuration in post operative follow up with a lesser incidence of varus collapse or implant failure.

Comparison of airway assessment tests for prediction of difficult intubation in obese patients: importance of thyromental height and upper lip bite test.

Prediction of difficult intubation (DI) has remained challenging for anesthesiologists and validity of airway assessment tests has not been fully investigated. This study aims to compare predictive values of these tests for prediction of DI in obese patients. One hundred ninety-six patients with Body Mass Index (BMI) ≥30 kg/m2 were included in this prospective study. Variables including intubation Difficulty Scale (IDS), thyromental height (TMH), hyomental distance (HMD) in extent and neutral neck position, HMD ratio (HMDR), sternomental distance (SMD), thyromental distance (TMD), ratio of height to TMD (RHTMD), width of mouth opening (MO), mandibular length (ML), Cormack-lehane (C-L) grade, upper lip bite test (ULBT), history of snoring, and obstructive sleep apnea were collected. Multiple logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine independent predictors of DI (defined as IDS≥5) and their cut off points. DI and difficult laryngoscopy (defined as C-L grade ≥3) were observed in 23% and 24.5% of the study population, respectively. Multiple logistic regression identified TMH (Odds ratio (OR):0.28, 95% confidence interval (CI):0.14-0.58, P=0.001), BMI (OR:1.18, 95% CI: 1.11-1.26, P<0.001), HMDR (OR:0.45, 95% CI:0.36-0.56, P<0.001) and ULBT (OR: 3.91, 95% CI: 2.14-7.14, P<0.001) as independent predictors of DI. Sensitivity of TMH<4.8 cm, BMI>34.9 kg/m2, HMDR<1.4 and ULBT class ≥2 were determined as 75.1%, 73.3%,62.3% and 93.3% respectively. TMH and ULBT had the highest sensitivity for prediction of DI in obese patients in this study and it is recommended to be considered as part of airway assessment in this patient population.

A two-handed airway maneuver of mandibular advancement and mouth opening in the neutral neck position for immobilization of the cervical spine.

Immobilization of the cervical spine after trauma is recommended as standard care to prevent secondary injury. We tested the hypothesis that a two-handed airway maneuver, consisting of mandibular advancement and mouth opening in the neutral neck position, would minimize changes in the angle of the cervical vertebrae at the C0/4 level and tidal volume in non-obese patients under anesthesia with neuromuscular blockade. Twenty consecutive patients without cervical spine injury undergoing general anesthesia were enrolled and evaluated. The primary variable was change in the angle of the cervical vertebrae at the C0/4 level during mask ventilation using the modified two-handed technique. Secondary variables included changes in the angles of the cervical vertebrae at each level between C0 and C4, anterior movement of the vertebral bodies, change in the angle between the head and neck, change in the pharyngeal airway space, and tidal volume during mask ventilation. The two-handed airway maneuver of mandibular advancement and mouth opening resulted in statistically significant changes in the angle of the cervical spine at the C0/4 level (3.2 ± 3.0 degrees, P < 0.001) and the C3/4 level (1.4 ± 2.2 degrees, P = 0.01). The two-handed airway maneuver provided adequate mask ventilation without anterior movement of the vertebral bodies. Our study suggests that a two-handed airway maneuver of mandibular advancement and mouth opening in the neutral neck position results in only slight change in the cervical vertebral angle at the C0/4 level in non-obese patients under general anesthesia with neuromuscular blockade.

Effects of head position on back squat power performance

The effect of head positioning is often not accounted for when optimising performance in the back squat exercise. The primary aim of the study was to identify the most advantageous head position for peak power (PP), peak velocity (PV) and peak force (PF) performance in the back squat exercise. A secondary aim was to identify the most favourable head position. Twenty male rugby union players performed 1x3 repetitions at 75% one repetition maximum (1RM) to determine their preferred pre-intervention head position, followed by 1x3 at 75% 1RM in a flexed (FP), extended (EP) and neutral (NP) neck position, performed in a counterbalanced and randomised order. PP, PV, PF and comfort level (CL) were measured during each repetition. FP resulted in significantly higher PP (3147.50 ± 464.70 W; p<0.05) compared to EP (2730 ± 427.83 W) and NP (2912.95 ± 441.16 W). However, NP resulted in significantly greater CL than FP and EP (3.65 ± 0.59; p<0.05). Therefore, when performing the back squat at 75% 1RM, the FP can be adopted to optimise power performance if there is no pain and no detriment to movement kinematics.

Diagnostic Role of Flexion-extension Central Motor Conduction Time in Cervical Spondylotic Myelopathy.

Study Design.Retrospective studyObjective.The purpose of this study was to assess the diagnostic usefulness of flexion-extension central motor conduction time(CMCT) for patients with cervical spondylotic myelopathy (CSM).Summary of Background Data.Previous reports have suggested that cervical cord compression can be aggravated by neck motions. Thus, the importance of dynamic magnetic resonance imaging (MRI) has been emphasized. However, authors of this study found no reports conducted at the time of this research on whether flexion-extension CMCT was useful for detecting myelopathy.Methods.We enrolled 227 patients with CSM for this study. We acquired CMCT recorded from the abductor pollicis brevis muscle. All patients underwent a dynamic CMCT study during neck flexion and extension as well as a static study during neutral neck. Static and dynamic MRIs were also scanned. We read all MR images using Muhle classification (MC).Results.CMCT was significantly delayed with flexion (P < 0.01) and extension (P < 0.01) compared to neutral neck position. Patients with MC grade 1 and 2 showed significant lag in CMCT during flexion and extension. No significant lag by neck motion was observed for those in the MC grade 3. We also evaluated the amount of CMCT variation according to MC grade change (G0, G1, G2) by neck motion. Delta-CMCT of both G1 and G2 were significantly larger than those of G0 in both flexion and extension. In neutral neck, the CMCT showed significant difference between MC grades 1 and 3. They also displayed significant delay with delay with high signal intensity on T2 MRI. More than one-third of the patients whose CMCT was within normal range in neutral neck presented abnormal CMCT in neck flexion (35.3%) and extension (37.8%).Conclusion.CMCT is significantly slower in both neck flexion and neck extension than in the neutral neck position. These findings reflect the dynamic cervical cord impingement.Level of Evidence: 4

Neck rotation modulates motor-evoked potential duration of proximal muscle cortical representations in healthy adults

Transcranial magnetic stimulation (TMS) produces motor-evoked potentials (MEP) used to infer changes in corticomotor excitability. In humans, neck rotation can probe reticulospinal input on corticomotor output. This study investigated the effect of neck rotation on MEP duration in a proximal and distal upper limb muscle and compared responses between rest and preactivation. Single-pulse TMS to motor cortex was used to evoke MEPs at two stimulus intensities in 18 healthy adults (20-40years). Surface electromyography recorded MEPs from the non-dominant biceps brachii (BB) and first dorsal interosseous (FDI). Participants were seated with the target muscle at rest or 10% preactivated, and head rotated ipsilateral, contralateral, or in neutral position. The primary outcome was MEP tail, defined as the mean difference in MEP duration between active and rest trials. Secondary outcomes were MEP duration and amplitude. MEP tail was modulated by neck rotation in the proximal BB (P = 0.03) but not distal FDI (P > 0.19), with shorter duration during ipsilateral or contralateral rotation relative to neutral. In a neutral neck position, MEP duration was prolonged by muscle preactivation and higher TMS intensities in the FDI and BB (P < 0.03). Neck rotation attenuated the prolongation of MEP duration during preactivation in the BB, but not the FDI. Neck rotation had no effect on MEP amplitude for either muscle (P > 0.05). Modulation of the late portion of the MEP by rotation of the neck could indicate subcortical projections to alpha-motoneuron pools are stronger in proximal than distal upper limb muscles. These findings may have relevance for using MEP duration as a neural biomarker in neurological diseases.

Dysphagia Precipitated by Cervical Lordosis in the Aged

A lordotic curve of the cervical spine in the aged is a physiological curvature of the cervical spine. The swallowing disorder precipitated by lordosis of the cervical spine in the aged, the swallowing function and intervention were reported on. An 86-year-old woman complained of swallowing difficulty for a few months. A lordotic curve (physiological curvature) of the cervical spine was observed. In the neutral neck position, the cervical lordotic angle was 29° using the Cobb C2-C7 method. When the lordotic curve of the cervical spine was intentionally straightened, the lordotic angle became 0°, the laryngeal elevation changed from 0.5 times the height of a cervical vertebra to 1.75 times, the laryngeal elevation delay time changed from 0.5 seconds to 0.23, the percent laryngeal elevation changed from 50% to 72% and pharyngeal transit time changed from 0.83 seconds to 0.75. Lordosis of the cervical spine inhibited laryngeal elevation and influenced the swallowing function. In cases in which lordotic curvature of the cervical spine adversely influences the swallowing function in the aged, rehabilitation to manage the lordosis of the cervical spine is useful. For the purpose of effective intervention, not only diagnostic but also therapeutic videofluorographic examination of swallowing is very important.

The changes of endotracheal tube intracuff pressures after ear and head and neck surgery-related positions: a prospective observational study

IntroductionThe cuff of an endotracheal tube seals the airway to facilitate positive-pressure ventilation and reduce subglottic secretion aspiration. However, an increase or decrease in endotracheal tube intracuff pressure can lead to many morbidities. ObjectiveThe main purpose of this study is to investigate the effect of different head and neck positions on endotracheal tube intracuff pressure during ear and head and neck surgeries. MethodsA total of 90 patients undergoing elective right ear (Group 1: n=30), left ear (Group 2: n=30) or head and neck (Group 3: n=30) surgery were involved in the study. A standardized general anesthetic was given and cuffed endotracheal tubes by the assistance of video laryngoscope were placed in all patients. The pilot balloon of each endotracheal tube was connected to the pressure transducer and standard invasive pressure monitoring was set to measure intracuff pressure values continuously. The first intracuff pressure value was adjusted to 18.4mmHg (25cm H2O) at supine and neutral neck position. The patients then were given appropriate head and neck positions before related-surgery started. These positions were left rotation, right rotation and extension by under-shoulder pillow with left/right rotation for Groups 1, 2 and 3, respectively. The intracuff pressures were measured and noted after each position, at 15th, 30th, 60th, 90th minutes and before the extubation. If intracuff pressure deviated from the targeted value of 20–30cm H2O at anytime, it was set to 25cm H2O again. ResultsThe intracuff pressure values were increased from 25 to 26.73 (25–28.61) cm H2O after left neck rotation (p=0.009) and from 25 to 27.20 (25.52–28.67) cm H2O after right neck rotation (p=0.012) in Groups 1 and 2, respectively. In Group 3, intracuff pressure values at the neutral position, after extension by under-shoulder pillow and left or right rotation were 25, 29.41 (27.02–36.94) and 34.55 (28.43–37.31) cm H2O, respectively. There were significant differences between the neutral position and extension by under-shoulder pillow (p<0.001), and also between neutral position and rotation after extension (p<0.001). However, there was no statistically significant increase of intracuff pressure between extension by under-shoulder pillow and neck rotation after extension positions (p=0.033). ConclusionAccessing the continuous intracuff pressure value measurements before and during ear and head and neck surgeries is beneficial to avoid possible adverse effects/complications of surgical position-related pressure changes.