Neck In Neutral Position Research Articles

Normative value of deep neck flexors muscle strength measurement using pressure biofeedback unit and sphygmomanometer: An observational study

PurposeTo find out the normative value of deep neck flexor muscles strength using pressure biofeedback unit and sphygmomanometer. MethodsThe healthy individuals both male and female aged between 18 and 25 years were recruited by stratified random sampling method from a tertiary hospital. The procedure is performed with the patient in supine lying with the neck in a neutral position. To check strength, pressure biofeedback unit and sphygmomanometer were placed under occiput and ask the individual to do the movement is genteelly and slowly as a head nodding action (chin tuck). The performance was scored via the pressure level that patient achieves 3 repetitions for 10 s hold and interval timing for 10 s. And the pressure biofeedback unit and sphygmomanometer inflated with 40 mmHg and took three reading respectively. ResultOur result shows, in decreased of deep neck cervical flexor muscle Strength with age group 21 (20–22) in normal adult and underweight with age group 21 (19–23) and with BMI 21 (20.1–22.4) and 16.6 (16.1–17.6) respectively. In our study, the deep neck flexor strength of overweight adults with age group 22 (21–23) and with BMI 27.8 (25.9–29.4) is stronger is than the normal and underweight adults. ConclusionThe study concluded that the maximal Deep neck cervical flexor strength of overweight Adults is stronger than normal and underweight Adults. The difference is maintained in all age groups. The maximal Deep neck cervical flexor strength, for flexion is developed at neutral position of neck.

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.

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.

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.

Comparative evaluation of ease of tracheal intubation using Airtraq and intubating laryngeal mask airway with cervical spine immobilization

Tracheal intubation in cervical spine injury patients with application of Manual In Line Stabilization (MILS) of the cervical spine in neutral position is a challenge for the anesthesiologist since it makes visualization of the larynx more difficult using conventional laryngoscopy. Our study was conducted to compare ease of intubation using Airtraq and Intubating laryngeal mask airway(ILMA) in simulated cervical spine injury patient using MILS.100 ASA I/II patients (without cervical spine injury), aged 18-60 years were randomly allocated in two groups -Group A: Airtraq (n=50), Group I: ILMA (n=50). General anaesthesia was given as per standard protocol in all the patients, after that MILS was applied and patients intubated using Airtraq in group A and ILMA in group I with neck in neutral position. Time taken for intubation, number of attempts for intubation, ease of intubation with Airtraq/ILMA, hemodynamics and complications were compared.The mean time taken for intubation in the Group A was 12.6 ± 6.6 seconds and in the Group, I was 85.8 ± 36.6 seconds (p&amp;#60;0.001). Number of intubations attempts in Group A was significantly less as compared to the Group I (p= 0.027).Airtraq is a safer and faster alternative when compared to ILMA in patients with simulated cervical spine injury using manual in line stabilization.

The lengths of trachea and main bronchus in Chinese\xa0Shanghai population

The knowledge of airway length is the theoretical basis in the diagnosis and management of airway disease. The objective of this study is to measure the length of trachea and left and right main bronchus in Chinese Shanghai population. A total of 153 consecutive adult patients with minor pulmonary disease in Xinhua hospital were enrolled for bronchoscopy examination. Measurements were conducted on head and neck neutral position and height, weight and age for each patient were recorded either. Student t test and multiple linear regression was used to compare means between males and females and to analyze correlation among height, weight, sexual dimorphism and the lengths of the trachea and bronchus. The lengths of the trachea and left main bronchus are significantly different between male and female patients (P < 0.01), but not for the lengths of right main bronchus between man and woman. Multiple linear regression analysis showed that height but not sexual dimorphism and weight correlated with the lengths of the trachea and right main bronchus. The lengths of the trachea and left main bronchus are significantly longer in males than in females. Moreover, height but not sexual dimorphism and weight influenced the length of airway.

Comparison of Upper and Lower Cervical Muscle Strengths Between Subjects With and Without Forward Head Posture

Background: Forward head posture (FHP) is common postural malalignment. FHP is described relatively extension to upper cervical and lower cervical is relatively flexion. Although several researchers mentioned the lower cervical flexion posture in FHP, most of the studies related to FHP is focused on the deep cervical flexor function. Objects: The purposes of present study is to compare the cervical strength (upper cervical extension [UCE], lower cervical extension [LCE], upper cervical flexion [UCF], lower cervical flexion [LCF]) between individuals with and without FHP. Methods: Fifty-one participants are recruited. Participants who have the craniovertebral angle (CVA) less than 48 degree were classified to the FHP group (n = 24) and the others were included in without FHP group (n = 27). The cervical strength (UCE, LCE, UCF, LCF) were measured using Smart KEMA strength sensor and the strength data was normalized by body weight. All strength measurement conducted at head and neck neutral position in sitting. Independent t-test was used to compare the cervical strength between individuals with and without FHP. Results: The mean value of CVA was greater in without FHP group than with FHP group (p < 0.000). The strength value of UCF (p < 0.002) and LCE (p < 0.001) was significant less in FHP group than without FHP group. But no significant differences were seen in the LCF and UCE strength between two groups. Conclusion: UCF and LCE weakness in FHP group should be considered to evaluate and manage the individuals with FHP.

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.

The impact of restricted length of treatment field and anthropometric factors on selection of head and neck cancer patients for treatment on the MR-Linac.

Objective:This study investigates the impact of a restricted craniocaudal (CC) field length of <20 cm on the selection of head and neck cancer (HNC) patients who can be treated on the MR-Linac using a single isocentre technique. We also assess the effects of anthropometric factors and the neck position on the CC field length.Methods:110 HNC patients who underwent radical primary or adjuvant radiotherapy were retrospectively analysed. We assessed the proportion of treatment fields with a CC length of <20 cm and the effects of gender, height, hyo-sternal neck length (distance from superior surface of hyoid to sternal notch measured on the coronal reconstruction of the planning CT) and neck position on CC length.Results:95% of HNC patients had a CC field length <20 cm. Female patients showed a significantly shorter median CC length than male patients in both extended (p = 0.0003) and neutral (p = 0.008) neck positions. Neck position influenced the median CC length with neutral neck being significantly shorter than extended neck (p = 0.0119). Patient height and hyo-sternal neck length showed positive correlation with the CC length, with neck length in neutral position having the strongest correlation (r = 0.65, p = 0.0001 and r = 0.63, p < 0.0001, respectively for extended neck; r = 0.55, p = 0.0070 and r = 0.80, p < 0.0001, respectively for neutral neck). A hyo-sternal neck length of <14.6 cm predicted a CC length of <20 cm in neutral neck position.Conclusion:The majority of patients with HNC at the Royal Marsden Hospital have anthropometric features compatible with their being treated on the MR-Linac using a single isocentre technique. The absolute CC field size may vary according to primary tumour site, patient factors and neck position. A hyo-sternal neck length cut-off of 14.6 cm in the neutral neck position can be used as a surrogate marker for suitability of treatment on MR-Linac.Advances in knowledge:This paper highlights the potential impact of a restricted CC field in HNC patient selection for the MR-Linac treatment. This is the first report to suggest the use of neck length as a surrogate marker for suitability of treatment on the MR-Linac.

Cervical Canal Morphology: Effects of Neck Flexion in Normal Condition: New Elements for Biomechanical Simulations and Surgical Management.

Continuous measurements and computation of absolute metrics of cervical subarachnoid space (CSS) and spinal cord (SC) geometries proposed are based on in vivo magnetic resonance imaging and 3D reconstruction. The aim of the study is to offer a new methodology to continuously characterize and to quantify the detailed morphology of the CSS and the cervical SC in 3D for healthy subjects in both neutral supine and flexion. To the best of our knowledge, no study provides a morphological quantification by absolute indices based on the 3D reconstruction of SC and CSS thanks to in vivo magnetic resonance imaging. Moreover, no study provides a continuous description of the geometries. Absolute indices of SC (cross-sectional area, compression ratio, position in the canal, length) and of CSS (cross-sectional area, occupational ratio, lengths) were computed by measures from 3D semi-automatic reconstructions of high resolution in vivo magnetic resonance images (3D T2-SPACE sequence) on healthy subjects (N = 11) for two postures: supine neutral and flexion neck positions. The variability induced by the semi-automatic reconstruction and by the landmarks positioning were investigated by preliminary sensitivity analyses. Inter and intra-variability were also quantified on a randomly chosen part of our population (N = 5). The length and cross-sectional area of SC are significantly different (P < 0.05) in flexion compared with neutral neck position. Spinal cord stays centered in the canal for both postures. However, the cross-sectional area of CSS is submitted to low variation after C3 vertebra for both postures. Occupational ratio (OR) and compression ratio (CR) after C3 are significantly lower in flexion. This study presented interpretations of morphological measures: (1) left-right stability (described by the Left-Right eccentricity index) ensured by the denticulate ligaments and the nerve roots attached to the dural sheaths, (2) a Poisson effect of the SC was partially notified through its axial (antero-posterior [AP] diameter, OR, CR) and its longitudinal geometrical descriptions (length of spinal cord [LSC]). Such morphological data can be useful for geometrical finite element modeling and could now be used to compare with injured or symptomatic subjects. 3.