Severe head injury and reconstructive neurosurgery
Following a traumatic injury to the skull or brain, contusions of the brain or bleeding often occurs, which may also be associated with fractures of the skull bones or soft tissue injuries. Depending on the cause of the injury or other associated factors, infections, particularly abscesses may also cause problems. The acute neurological treatment in the case of space-occupying, symptomatic haemorrhage (bleeding) is to remove the blood clot and, where necessary, repair the skull and/or skin injury. Afterwards, depending on the severity of the injury, intensive care may be required.
Bleeding in or around the brain (haematomas) can be categorised as follows, and can occur in combination:
Extradural haematomas lie between the skull bone and the tough outer lining of the brain, the dura mater. They usually occur following an injury to an arterial blood vessel outside the dura mater, through superficial bleeding from a large vein (sinus) or from bleeding from a fractured skull. The latter can occasionally directly injure an artery supplying the brain lining (meninges), causing severe bleeding. Extradural haematomas can enlarge quickly and in such cases the neurosurgical removal of the clot and control of the bleeding is necessary. The prognosis following an extradural haematoma is improved by rapid neurosurgical intervention and a complete recovery without neurological deficits is entirely possible.
Subdural haematomas lie between the tough outer layer of the brain (the dura mater) and the thin, web-like layer – the arachnoid – found beneath it. These clots most commonly arise following the tearing of a vein, which run between the surface of the brain and the large venous sinuses running in the dura mater. In cases of severe trauma, brain contusions can lead directly to subdural haematomas.
Depending on the severity of the trauma and the development of the bleeding over time, it is possible to distinguish between acute and chronic subdural haematomas – a combination of both is also possible. In addition to this categorisation, the type and degree of energy involved in the initial traumatic injury is of great prognostic importance. In the case of acute subdural haematomas, rapid evacuation of the clot is usually required – in many cases this may also involve the removal of a piece of the side of the skull to decompress the injured brain with the skin closed over the gap. This piece of skull may be put back later or replaced with an artificial implant.
Chronic subdural haematomas, which often occur in more elderly patients, can occur after surprisingly inconsequential knocks to the head, or after a more severe injury. These are often the result of the torn “bridging veins” mentioned earlier – these bleed very slowly and it can takes weeks or sometimes months for symptoms to develop. Depending on the location of the resultant haematoma, symptoms such as headache, cognitive problems, speech difficulties, weakness of the limbs or seizures can develop – if these occur, surgical evacuation is usually indicated. If an operation is performed promptly, recovery without residual symptoms is possible.
Intracerebral haematomas are blood clots within the brain tissue which usually occur after damage to blood vessels following blunt or sharp trauma. Depending upon the size and position of the clot within the brain, neurosurgical symptoms vary a great deal and in every case a careful CT scan, and sometimes MR imaging, is necessary to determine the best course of action. In the case of significant space-occupying effects, that is, neurological deficits and /or deformation of the surrounding brain through pressure exerted by the clot and associated swelling, a neurosurgical operation to remove the clot is usually indicated.
Reconstruction of the skull:
After severe head injury, deformation and defects in the skull can occur either due to the forces of the initial injury or because part of the skull had to be removed to prevent pressure building in the skull. In the latter case, a piece of the skull is removed (craniectomy) and the skin closed over the gap. This operation is also performed following major strokes to relieve pressure associated with brain swelling. Once the brain swelling has settled, the gap in the skull can be recovered to protect the underlying brain long-term and to restore the natural contours of the skull. Modern bioengineering now allows the precise reconstruction of the skull using artificial implants. Using these techniques, small defects can be repaired using a malleable material to perfectly fill the gap with excellent cosmetic results. In the case of larger defects, an implant can be prepared using a high-resolution CT scan of the skull – the skull is first perfectly reconstructed in a simulation before the implant is individually manufactured. With such implants, the optimal fitting accuracy can be guaranteed and, after the skin is closed, the normal skull contour is fully restored.