There are several complications of text-neck syndrome. They can involve the eyes, the heart and lungs, the head, and the psychological field. An elevated number of studies all over the world have analyzed musculoskeletal pain in children and adolescents. There is now enough evidence to support the association between flexing toward the neck and symptoms referred to the cervical spine.
1.3.1. Musculoskeletal Pain
Some authors conducted a study in which they examined a sample of 207 children and adolescents with nonspecific neck pain [
1]. In all patients (100% of the sample), a cervical neck pain irradiated to the back and the shoulders was reported. This pain had duration of more than 6 months and was not associated to sensory or motor deficits. Twenty-seven patients with dorso-lumbar scoliosis were excluded from the study; the study focused on the remaining 180 patients, without any other diseases, but with the diagnosis of musculoskeletal neck pain with spasm. The age range was from 8 to 17 years, with the mean age of 14 years. The demographic characteristics of the children and adolescents in the study show that all the 180 participants (100%) reported forward flexion of neck while they are studying and while they are using smartphones and/or tablets: the study demonstrates that all participants (100%) presented a strong flexion of the neck (≥45 degrees) during the daily activities and that all participants spent an average of 5 to 7 h a day on their smartphones and handheld devices. As side-effects on short-time, the study shows that the main pain location is on the neck (100% of the sample), followed by pain on shoulders (69%), lower back (61%), and then arms (13%); the eye symptoms are eye strain (12%), dry eyes (7%), and near sightedness (3%); the psychological and social effects evidenced in this study are irritability (82%), stress (62%), anxiety (59%), poor communication (82%), and decreased school marks (64%) [
1].
Another study evaluated upper quadrant musculoskeletal pain (UQMP) in children and adolescents as a common health problem, due to the increased sedentary lifestyles and the growing use of screen-based activities [
22,
23]. The aim of this study was to understand the risk factors to implement preventive and treatment strategies. It has been described how different sitting postures can influence the head/neck posture and the activity of the muscles of the cervicothoracic spine in a very significant way [
24]. Therefore, the sitting position and the duration can contribute to low back pain and especially on the UQMP. An evaluation questionnaire about the causative factors for UQMP described by children and adolescents was put to a group of children and adolescents, to determine if there is evidence of correlation between sitting and UQMP and the different elements of sitting related to UQMP in this population. The aim of the study was to understand the assessment of posture that provides information about the biomechanical alignment of the bone structures at any specific moment in time. Four elements related to UQMP were identified: the sitting duration [
25,
26]; the activities while sitting [
25,
26,
27,
28]; the dynamism (amount of movement while seated) [
26,
29]; and postural angles (spinal angles while seated) [
30,
31,
32,
33,
34]. It was evaluated that, if sitting posture is prolonged and static, certain anatomical structures are adversely affected by prolonged strain; time by time these structures could consequently become the cause of musculoskeletal pain [
35,
36]. So, it can be concluded that there is an unequivocal link between sitting and UQMP in children and adolescents and that postural angles during sitting should be considered a possible risk factor for UQMP, that could be better explored in future research.
In other studies, a significant association between sitting and UQMP in children and adolescents has been highlighted [
26,
27,
28,
29,
30,
31,
32,
33,
36,
37]. Another study evaluated a cohort of asymptomatic high-school students, with the aim to describe the variability of five postural while working on desktop computers and the relationship between the postural angles and age, gender, height, weight, and computer use; 821 students were screened at baseline and 240 students after one year of follow-up [
38,
39].
Straker et al. studied also the postural differences between adolescent computer and non-computer users and found that computer users had increased neck flexion and increased pelvic tilt [
33]. The same authors also showed that the increased computer use was associated to increased head flexion and neck flexion especially for boys and increased lumbar lordosis for girls [
40].
In an Australian study, 33 adolescents aged from 12 to 15 years were evaluated to verify the correlation between information and communication technology (ICT) use and musculoskeletal discomfort. The participants were eligible if they used ICT at least once per week, for almost 15 min at a time, in their normal activities; adolescents with a pre-existing diagnosis of musculoskeletal disorder were excluded. This study clearly showed an increase of prevalence of low-level discomfort, more frequently in the legs, head/neck, back and shoulders in those using ICT. The types of ICT most used were TV, desktop and laptop computers, mobile telephones, and portable hand-held gaming devices. The specific areas involved with ICT use, such as head, neck, shoulders, and upper back and arms/hand were significantly associated with the amount of ICT use and discomfort described at the end of the day. No significant correlation was found between the amount of ICT use and the discomfort in the areas of the body commonly affected by ICT use (such the head, neck, shoulders, upper back and arms/hands) [
41].
A study in Hong Kong examined the ergonomic issues involved in computer workstations: the study was conducted in the home environment of students at primary school age. The authors considered different factors, such as anthropometric, postural, and ergonomic considerations, to show the effect of computer use in the home environment on the children. A sample of 15 participants, 6 males and 9 females, aged from 8 to 11 years old, all attending the primary school levels 3–6 were collected. This sample did not highlight discomfort symptoms related to computer use, maybe because they were not intensive users or because they do not suffer serious musculoskeletal symptoms related to computer use. Only 4 out of 15 highlighted a discomfort directly related to computer use, while in other studies with a larger sample the discomfort was more frequently evaluated. This study aimed to investigate how computer use in primary school students in the home environment can influence musculoskeletal symptoms. It was identified that the computer furniture is not ideal for users; this contributes to have constrained and awkward postures during computer use. It is possible that these mal-adaptive postures may become habitual and extended into adolescence or adulthood. About 20–30% of the children reported musculoskeletal discomfort related to computer use. It becomes very important to understand the ergonomic issues in more extensive research studies, maybe using motion analysis and electromyography measurements to better understand children’s postural control and variability during computer use in the home environment [
42].
Another study examined the adolescent upper quadrant musculoskeletal pain (UQMP), as a significant health concern with a worldwide prevalence of 30% [
43,
44,
45]. Also in this study, the discomfort for musculoskeletal pain in adolescents is related to several causes: reduced social interactions, mental health, school attendance, scholastic competence, and participation in physical activities [
44,
46]. The etiology of adolescent UQMP is multifactorial, it can include complex physical and psychosocial factors [
44,
47,
48]. Nowadays, adolescents are increasingly exposed to screen-based activities at home and also at school [
23].
A large number of studies report a significant association in high school students between neck pain and weekly computer use of nine or more hours [
49]. The aim of one study was to identify specific spinal segmental postures associated with development of UQMP in a 12-month period. A sample of 240 high-school students was evaluated, aged between 15 and 17 years, living in the Western Cape metropole (South Africa), asymptomatic and naïve to computing classes. The students were screened for UQMP by completing the pain section of the Computer Usage Questionnaire (CUQ), developed and validated in South African high school settings [
50]. In this study, for the first time, the development of UQMP is described in relation to postural angles, computer use, anxiety, and depression. This study also analyzed the correlation between increased head flexion (HF), defined as the head-on-neck alignment and seated-related adolescent UQMP, developed in a period of 6 to 12 months, for students that use computing studies at school [
30]. Thus an association between UQMP and computer use has been demonstrated [
51]; in addition, prolonged sitting postures could be the cause of musculoskeletal disorders on head, neck, shoulder, and midback pain [
25,
27,
36]. In 44% of cases, headache and neck pain could be related to pathological changes in the upper cervical structures in response to increased load on active and passive structures, because of the upper cervical nerve innervation [
52,
53,
54]. The most important anatomical structure is the trapezius muscle, which is fundamental in the linking between the spinal column and the upper arm [
55]. This muscle is innervated by the spinal accessory nerve (Cranial nerve XI) and the cervical plexus (C1-C4) [
56]. The increased HF could potentially lead to pain in these nerves; this has been confirmed in a study in which the authors reported a positive correlation between upper trapezius muscle activity and HF in children [
57]. Further research must investigate the field of classroom furniture (chair, desk, and monitor height) and postural hygiene (knowledge and postural habits), which could contribute to increased HF posture.
In addition, a study performed in Thailand investigated the common complaint of non-specific symptoms of musculoskeletal pain that can have a sudden onset in adolescent age and can have long-lasting symptoms [
18,
58]. The symptoms related to musculoskeletal pain that affect a large portion of school-adolescents is a great health burden and an increased cause of augmented cost living because it involve the performance of daily living activities such as studying, exercising, or social participation. Musculoskeletal pain at the shoulders is found to be associated with headache, that is one of the most common public health problems in children and adolescents; it can cause muscle tension and it can be attributed also to tight muscles in the shoulders, neck, scalp, and jaw [
59,
60].
A cross-sectional questionnaire was used in primary and secondary Thailand schools, in Khon Kaen and Phitsanulok Provinces, from November 2009 to June 2011, recruiting 2750 participants. Thai school-age adolescents reported a high prevalence of neck and shoulder pain, as European adolescents (from 15% to 28%) [
61,
62] and Chinese teen-agers (41.1%) [
63].
The prevalence of musculoskeletal pain symptoms in school-age adolescents is different among age, groups, and sex. Headache was the most common musculoskeletal pain symptom referred with the highest prevalence in Thai school-age adolescents. Additionally, it was found that headache and musculoskeletal pain symptoms were more prevalent in girls than in boys and these rates tend to be higher in older adolescents. Ankle or foot pain was a common musculoskeletal pain among younger boys and girls playing sports. Neck and shoulder pain were a common musculoskeletal pain among older boys and girls and were associated with computer use and school bag carrying.
Chronic pain in the neck and shoulders can be referred to the head, causing headache, especially tension-type headache, which is quite common in adolescents. Trigger points in the head, neck, and shoulders shared similar pain patterns with chronic tension type of headache in children [
64], so we can justify why neck and shoulder pain can begin in early adolescence and persist into chronic musculoskeletal problems in adulthood [
58].
1.3.5. Further Comorbidities
Some new studies have suggested that forward postures, like we have while studying, emailing, texting, surfing the web, and playing video games, are related to hyper-kyphosis, which is associated to cardiovascular problems and pulmonary disease. In fact, when someone looks at a smartphone or a tablet, he drops his head and rounds his shoulders while looking down, so there is a restriction of the muscles of the ribs and impeachment in movement that make it harder to take a full breath [
72].
There is also an important relation between increased neck flexion and increased weight, probably due to the decreased physical activity [
40].
The prevalence of headaches, especially migraines, has been studied among school-age children and adolescents, and it varies according to age and sex [
73]. A Swedish study found a 48% incidence of headache among schoolchildren aged 7–18 years, while Fichtel and Larsson found that headache is the most common pain among girls (42%) [
74,
75].
A study conducted by the Commonsense Census analyzed the mobile media and the use in children and adolescents. It demonstrated that mobile media have become an essential part of the children’s media landscape, across all levels of society.
Nearly the totality of children (98%) (aged 8 or less) have some type of mobile device and a TV in their home. Ninety-five percent of families with children have a smartphone, with a trending up from 41% in 2011 to 63% in 2013, and 78% of families have a tablet (from 8% in 2011 up to 40% in 2013). Indeed, 42% of children have their own tablet device, from less than 1% in 2011 up to 7% in 2013. The main activities of children on mobile devices are watching TV and playing video games. It is estimated that around 7 out of 10 children under the age of 8 (around 70%) have watched videos on YouTube in their lifetime and played video games on a mobile device, while only 59% of children have watched TV shows or movies on a mobile device. Only 28% of children have read a book on a smartphone or tablet [
76].