OSTEOMYELITIS OF SKULL BONES
An osteomyelitis of the cranial bones is usually the result of direct penetration of the infection. It can be seen affecting the bone flap after craniotomy, or after skeletal traction with tongs in cervical fractures or adjacent to purulent sinusitis or otitis. A metastatic haematogeneous osteomyelitis is extremely rare. The most common organism causing osteomyelitis is staphylococcus, but other organisms or a combination of them can be identified. Local pain and oedema are the main clinical manifestations.
Fever and the other usual signs of infection can also be present. X-rays films reveal destruction of the bone tissue.
Osteomyelitis of the skull bones needs surgical treatment. The incision of the scalp over the osteomyelitic focus should be sufficiently large, permitting exploration of the entire affected bone surface. When it is a case of postcraniotomy osteomyelitis, it often requires total removal of the bone flap, using the previous surgical incision (Fig. 7-1). When the osteomyelitis doesn't show the integrity of the calvaria to be broadly affected, a burr hole is drilled at the border of osteomyelitic focus and the affected bone is removed completely by nibbling (Fig. 7-2). The affected bone differs in colour and pus comes out of the diploic tissue instead of blood. The nibbling continues until a normal appearing bone tissue has been reached and the epidural space appears unaffected. Sinogenic osteomyelitis must be treated simultaneously with the source of infection. Intraoperative antibiotics are used i.v., and for wound irrigation.
Closure is as usual with a drainage left epidurally for a few days. Antibiotic therapy depends upon the results of the bacteriological investigations and continues for up to 3 - 4 weeks after the surgical treatment.
The subsequently required cranioplasty is postponed for at least 6 months after complete wound healing.
Some forms of cranial osteomyelitis (with very small and multiple foci) can be treated initially with antibiotics followed up frequent clinical and X-ray follow-up of the lesion.