The cervical collar is frequently used in cases of neck pain or acute neck pain in which mobility is very limited and it is difficult to support the head itself. Cervical / neck collars are commonly used by patients who have had cervical spine surgery to immobilize the neck. It is also used to treat neck pain, caused by acute trauma or chronic pain. After a whiplash injury, the neck can be used for both immobilization and pain reduction, although the value of the collar over early active mobilizations is questioned, as early mobilizations can improve cervical range of motion and reduce pain after whiplash injury.  The main purpose of neck collars is to prevent or minimize movement in the cervical spine. It also keeps the head in a comfortable position aligned with gravity, maintaining normal cervical lordosis. Although the term “cervical collar” has been widely used, the standardized and universally accepted term is now cervical orthosis. The name should be given depending on the parts of the body that the orthopedic device supports, such as the cervical orthosis, the cervical head orthosis or the cervico-thoracic orthosis, for example. Types Depending on the materials and the hardness of the material, cervical collars can be classified into: Soft collar Rigid collar Soft collar Soft collar.jpg Soft collars are made of felt. They are cut to mold around the patient’s neck and jaw, sized to fit the patient. However, these collars do not fully immobilize the neck, restrict movement, and are a kinesthetic reminder for the patient to reduce neck movement. Because the collar is under the chin and supports the chin, it minimizes the muscle contraction necessary against the forces of gravity to keep the head in a normal position. This type of collar does not really immobilize the neck    , it only limits flexion and extension in the final phase. These collars are tight around the neck and restrict perspiration. Rigid Collar Rigid Collar 1.jpg Rigid collars are similar in design to soft collars, but are constructed of plexiglass. They apply easily and are easy to keep clean, an advantage of the plastic collar. This type of collar is also supplied in different sizes to suit the patient. These collars restrict movement in flexion and extension.  They not only support the chin but also the occiput, which reduces active extension, especially in the final phase. One drawback of rigid collars is that they can potentially cause venous outflow obstruction, which can raise intracranial pressure.   If there is clear evidence of increased intracranial pressure, the collar should be removed or repositioned. 
The most prescribed are the Aspen, Malibu, Miami J and Philadelphia necklaces. All of these can be used with additional chest and head extension pieces to increase stability. Cervical collars are incorporated into rigid braces that restrain the head and chest. Examples include the sterno-occipital mandibular immobilization device (SOMI), the Lerman Minerva and Yale types. 
Effective duration of use The recommendation is that a necklace should be worn consistently for one week just for pain relief. After that, the use of the collar should be gradually reduced. If the collar is worn for a longer period, it could have several negative effects, such as: soft tissue contractures, muscle atrophy, loss of proprioception, thickening of the subscapular tissues and coordination, but also psychological dependence. 
However, several studies question the effectiveness of the neck neck compared to early mobilizations. Both reduce pain, but early mobilizations show greater improvement in cervical range of motion.   However, Pennie and Agambar suggest that there is no difference between the two interventions. 
Comparison When different types of cervical collar are compared with respect to mechanical stability (both actively and passively), all collars restrict movement to some extent. In order from least restrictive to most restrictive they are: soft collar, Philadelphia collar, SOMI.   although, the differences are not great. In general, collars do not provide a high level of mechanical restriction of movement and are variable between.
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