Women frequently express heightened neck discomfort even though they exhibit smaller neck flexion (NF) during smartphone use. Differences in natural posture while using smartphones may result in varying muscle activation patterns between genders. However, no study focused on this issue. This study investigated the influence of gender on neck muscle activity and NF when using smartphones, ranging from slight (20°) to nearly maximal forward head flexion, across different postures. We analyzed smartphone usage patterns in 16 men and 16 women and examined these behaviors across different scenarios: standing, supported sitting, and unsupported sitting, at 20°, 30°, 40°, and the maximum head angles. During data collection, muscle activity was measured, expressed as a percentage of the maximum voluntary contraction (%MVC), in the cervical erector spinae (CES) and upper trapezius (UTZ), along with NF. Results show significant influences of gender, head angle, and posture on all measures, with notable interactions among these variables. Women displayed higher muscle activities in CES and UTZ, yet exhibited lesser NF, while using smartphones in both standing (12.3%MVC, 10.7% MVC, and 69.0°, respectively) and unsupported sitting (10.8%MVC, 12.3%MVC, and 71.8°, respectively) compared to men (standing: 9.5%MVC, 8.8%MVC, and 76.1°; unsupported sitting: 9.7%MVC, 10.8%MVC, and 76.1°). This study provides a potential rationale for gender-related disparities in injury outcomes, emphasizing that women experience higher neck and shoulder discomfort level, despite their smaller NF during smartphone use, as found in previous research. Additionally, the cervical flexion-relaxation phenomenon may occur when the head angle exceeded 40°. The near-maximum head angle during smartphone use might induce the cervical flexion-relaxation phenomenon, potentially aggravating neck issues. We recommend limiting smartphone usage postures that exceed the near-maximum head angle, as they are commonly adopted by individuals in the daily smartphone activities.

BACKGROUND: Surgeons are at high risk of developing musculoskeletal symptoms due to a range of factors including, maladaptive positioning and surgical ergonomics. Cervical muscle strain and biomechanical load is most prevalent due to repetitive motions and prolonged static neck positioning. This issue is apparent through reports of prevalence between 10 and 74.4% among surgeons. The aim of this systematic review is to provide an objective assessment of the clinical evidence available and a descriptive analysis of the effects of kinematics and surgical ergonomics on the prevalence of surgeons\' cervical musculoskeletal pain.
METHODS: This is PRISMA-compliant systematic review of clinical studies assessing the prevalence of cervical musculoskeletal dysfunction in surgeons by searching PUBMED and Ovid EMBASE databases from inception to 19th October 2023. Study quality was graded according to the National Institutes of Health study quality assessment tools.
RESULTS: A total of 9 studies were included in the final qualitative analysis. The use of loupes, open surgery and excessive neck flexion (>30°) were associated with cervical dysfunction. Comparison of study outcomes was challenging due to heterogeneity within study methods and the paucity of methodological quality.
CONCLUSIONS: The current literature assessing ergonomic and biomechanical factors predisposing surgeons to cervical musculoskeletal dysfunction is insufficient to provide reliable guidance for clinicians. Although the literature identifies factors contributing to work-related cervical dysfunction, few attempt to evaluate interventions for improved surgical ergonomics. An objective assessment of interventions that prompt postural correction with the aim to improve neck pain in surgeon cohorts is warranted.

A 28-year-old man was brought to the emergency department with quadriparesis of acute onset after a bout of binge drinking. Evaluation revealed a mid-cervical myelopathy and magnetic resonance imaging (MRI) showed an acute compressive cervical myelopathy. He also developed rhabdomyolysis, and cervical paraspinal muscles showed MRI hyperintensities. After resolution of rhabdomyolysis and acute kidney injury, he underwent cervical spine fixation. He was found to have acute dropped head syndrome with secondary compressive myelopathy.

Background Extreme neck positioning to facilitate craniotomy can result in impaired venous drainage from the brain and a subsequent rise in increased intracranial pressure (ICP). The effects of varied neck positioning intraoperatively on ultrasonographic optic nerve sheath diameter (USG-ONSD) are still unexplored. This study aims to quantify the angle of neck rotation and flexion that can cause a significant increase in USG-ONSD in patients undergoing elective craniotomy. Methods A total of 100 patients were recruited in this non-randomized study and equally divided into two groups. In one group, patients with neck rotation ≤30 degrees and in another group, patients with neck rotation >30 degrees with varying degrees of neck flexion were included. The average of three USG-ONSD measurements in both eyes was obtained and compared in both groups at baseline, after positioning, and at the end of the surgery after making the neck neutral. Results The results of 100 recruited patients were analyzed. All the patients had neck flexion in the range of 40° to 45°, whereas the neck rotation ranged from 10° to 45°. The USG-ONSD of both eyes changed significantly from baseline to post-positioning time point in patients with neck rotation >30° (right eye p=0.038, left eye p=0.04) when compared to neck rotation ≤30°. There was no significant change in USG-ONSD from baseline to the postoperative time point after making the neck neutral (right eye p=0.245, left eye p=0.850) in both groups. Conclusions This study demonstrates that USG-ONSD, a surrogate measure of ICP, increased significantly after neck flexion with rotation >30° in neurosurgical patients. However, USG-ONSD becomes comparable to baseline after putting the patient\'s neck in a neutral position after surgery.

A 28-year-old man was brought to the emergency department with quadriparesis of acute onset after a bout of binge drinking. Evaluation revealed a mid-cervical myelopathy and magnetic resonance imaging (MRI) showed an acute compressive cervical myelopathy. He also developed rhabdomyolysis, and cervical paraspinal muscles showed MRI hyperintensities. After resolution of rhabdomyolysis and acute kidney injury, he underwent cervical spine fixation. He was found to have acute dropped head syndrome with secondary compressive myelopathy.

Carcinoma of the head, neck and face is a challenge faced by surgeons worldwide. This case report presents a complicated surgical approach utilised in a patient diagnosed with right lower lip and gingivobuccal sulcus carcinoma, with a fixed neck flexion deformity due to ankylosing spondylitis. The patient, a 55-year-old man with cervical kyphosis, was declared inoperable due to his complex anaesthetic and surgical requirements. We performed a successful wide local excision of the tumour with a right marginal mandibulectomy, and later reconstructed the defect using a left free radial forearm flap.

Neck flexion and extension show differences in various physiological factors, such as sympathetic nerve activity and intracranial pressure (ICP). We hypothesized that differences would exist in steady-state cerebral blood flow and dynamic cerebral autoregulation between neck flexion and extension in seated, healthy young adults. Fifteen healthy adults were studied in the sitting position. Data were collected during neck flexion and extension in random order for 6 min each on the same day. Arterial pressure at the heart level was measured using a cuff sphygmomanometer. Mean arterial pressure at the middle cerebral artery (MCA) level (MAPMCA ) was calculated by subtracting the hydrostatic pressure difference between heart and MCA levels from mean arterial pressure at the heart level. Non-invasive cerebral perfusion pressure (nCPP) was estimated as the MAPMCA minus the non-invasive ICP as determined from transcranial Doppler ultrasonography. Waveforms of arterial pressure in the finger and blood velocity in the MCA (MCAv) were obtained. Dynamic cerebral autoregulation was evaluated by transfer function analysis between these waveforms. The results showed that nCPP was significantly higher during neck flexion than during neck extension (p = 0.004). However, no significant differences were observed in mean MCAv (p = 0.752). Likewise, no significant differences were observed in any of the three indices of dynamic cerebral autoregulation in any frequency range. Although non-invasively estimated cerebral perfusion pressure was significantly higher during neck flexion than during neck extension, no differences in steady-state cerebral blood flow or dynamic cerebral autoregulation were evident between neck flexion and extension in seated healthy adults.

A variety of factors could contribute to facial oedema during a prone neurosurgical procedure. For optimal surgical exposure, suboccipital cranial surgeries frequently necessitate extreme neck flexion. Extreme neck flexion in the prone position can impair venous drainage of the facial and oropharyngeal structures, leading to life-threatening oedema, so a two-fingerbreadth space between the chin and the sternum is critical. We present a case of massive facial oedema with submandibular swelling in a patient who underwent foramen magnum decompression in the prone position for Arnold Chiari malformation.

Prior investigations have been primarily conducted in a laboratory to examine the effects of the smartphone use on the neck and head positions, whether these results are applicable to actual conditions is still unknown. This field survey thus analyzed the neck flexion (NF), head flexion (HF), gaze angle (GA), and viewing distance (VD) of smartphone users in public areas in Taipei, Taiwan. Six hundred smartphone users (300 men and 300 women) were photographed sagittally in standing, supported sitting, or unsupported sitting postures while using a smartphone. Results showed that women had significantly less NF and HF and shorter VDs than male users. Regardless of gender, higher NF was observed for standing than for sitting. Women had similar NF and HF while sitting supported and unsupported, but both were significantly lower than those while standing. By contrast, male users had higher NF and HF during unsupported sitting than during supported sitting. The NF (45°-50°) was much greater than the recommended maximum safe NF of 15°. Women may be at higher risk of visual strain because of shorter VD.

OBJECTIVE: The \"chin-down\" posture involves tucking the chin to the neck. However, clinicians and researchers have their own forms of the chin-down posture: some consider it to be head and neck flexion, whereas others consider it to be head flexion alone. The purpose of this study was to evaluate the effects of head, neck and combined head-and-neck flexion postures separately.
METHODS: Ten healthy volunteers participated in the study. The head and neck were set in neutral (N), head flexion (HF), neck flexion (NF) or combined head-and-neck flexion (HFNF) positions. Participants were instructed to swallow 4 ml of thick barium liquid in an upright sitting position. Head and neck angles at rest, distances in the pharynx and larynx at rest, and duration of swallowing were measured. Statistical analysis was performed with a paired t-test with Bonferroni correction.
RESULTS: Head angles in HF, NF and HFNF positions were significantly greater than in the N position. Neck angles were significantly greater in the NF position than in the N position. The distance between the tongue base and the posterior pharyngeal wall, the vallecular space and the airway entrance were smaller in the HF position than in the N position. The tongue base was in contact with the posterior pharyngeal wall longer in the HF position than in the N position.
CONCLUSIONS: Because HF, NF and HFNF positions have different effects, we recommend the use of these terms instead of \"chin-down position.\"