Head immobilization

Anatomical references

The head immobiliser system is based on the reconstruction of a unique mass and it is a support which can block kinetic components applied to head. The structure and fixing systems permit the elimination of movement resulting forces. Common immobilisation systems hinder forces applied on head by means of masses blocked on the immobilisation support. The head blockage in supports is made by a system of "tie-rod" so that it will be more elastic. The balance condition of a lying patient head is unstable; for this reason a head immobiliser have to assure, in few actions, a steady balance resis- tant to stresses. It must also be effective in keeping the position of body blocked by the immobilisation support even if there are relevant energies.

Why
The head immobilisation system is required for patients with a probable cranium-cervical trauma which have to be moved or transported. Every kind of stress inflicted on the head will be absorbed by cervical articulations and by the structure of the skull. The immobilisation limits kinetic energy dissipation by compounding articulated masses of the patient in one mass. The head immobiliser acts on skull structures if it is possible exploiting cervical collar action. It immobilises patient head in various elasticity degrees according to differents sizes of collars. The head immobiliser and the cervical collar make up a system that includes spinal board, fixing straps, legs immobiliser and so on. It is necessary that all the body is fixed to supports with the same elasticity degree in order to avoid any kind of pressure on spine or on other injured parts.

Where
The head immobiliser is effective on hard, plain and thermically cut-off supports which permit to put in the right position the traumatised patient during the time of the transport. It is useless with scoop stretchers where structures cannot be immobilised with the same elasticity along all the body and where it is impos- sible to immobilise a patient for the transport because they are not regular or insulator structures. It is not recommended for vacuum mattresses where gripping points are not usable. It is possible to use the head immobiliser with transportation stretchers only with containing and not with immobilising purposes.

When
In every case because all patients must be considered suspected cervical traumatised. Whenever the rachis must be aligned in order to avoid kinetic energy dissipation.

Compatibility
Most of head immobilising systems impede patient examination procedures.Usually head immobilisers are radio-compatibles because their materials have low density and/or uniform surface. They can be visible under X-Rays and TAC and NMR examinations. The immobilising sys- tem have to be guaranteed until the exclusion of major lesions. But if there are difficulty in diagnostics procedures the head immobilising system can be replaced with lateral provisional stuffing only in protected environment with scanty stresses.

Mass and speed matters
The skull mass is linked to trunk by the elastic structure of cervical spine. It is subject to kinetic energy during transport according to its mass in a ratio of: Ec = 1/2 mv2 where v is the speed of patient transportation and M the mass of bound part. A rigid immobilisation of patient with trauma is fundamental to avoid that the kinetic energy transfers itself to cervical rachis but also transport conditions are important as well. The elimination of all stresses such as accelerations on vertical and centrifugal axis due to vehicle driving are first aid unavoidable components.