11 - Extrinsic lesions of the CNS

Summary

In this chapter the focus will be restricted to the following:

Tumours of the meninges

Tumours of the nerve sheaths

Acoustic neuroma

Trigeminal neuroma

Jugular neuroma

Tumours of developmental origin

Dermoid and epidermoid cysts

Craniopharyngiomas

Colloid cysts

Tumours involving the nervous system secondarily

Chemodectomas (glomus tumours)

Chordomas and chondrosarcomas

Pituitary tumours and vascular developmental abnormality are covered elsewhere in this book (Chapters 7 and 12).

Neurosurgery has evolved rapidly, helped by development of reliable anaesthesia, excellent preoperative imaging, improved microscopes, specialist microinstruments and a better understanding of the pathophysiology of the nervous system. Large strides are being made in the subspecialties of paediatric, spinal, oncologic, neurovascular and skull base surgery, with surgeons now tackling problems which would have been considered inoperable only a decade ago. Such major changes in surgical practice make it difficult to include the older series in this chapter for as the techniques change so do the outcomes. Even the risks of general complications such as deep venous thrombosis and pneumonia have been modified by early postoperative mobilization, aggressive physiotherapy and the use of perioperative prophylaxis such as subcutaneous heparin. Wherever possible, large, recent series have been consulted in an attempt to establish the current mortality and morbidity for each of the lesions covered. However, it is disappointing to note that although many of the publications list the complications of surgery for these diseases, most do not objectively assess the overall outcome in terms of postoperative functional state, quality of life and patient satisfaction with treatment.