Spontaneous spinal cord herniation.

Spontaneous spinal cord herniation is a rare and under recognized condition. The commonest presentation is a Brown-sequard syndrome. It most commonly occurs in the thoracic region through an anterolateral dural defect, and the pathophysiology is ill understood. We present a case of spontaneous spinal cord herniation along with a review of literature.

Sural nerve fibre pathology in diabetic patients with mild neuropathy: relationship to pain, quantitative sensory testing and peripheral nerve electrophysiology.

Nerve fibre pathology is poorly described in diabetic patients with mild neuropathy and has not been adequately related to clinical evaluation, quantitative sensory examination and neurophysiology. Sural nerve myelinated and unmyelinated fibre pathology was morphometrically quantified and related to the presence of pain and conventional measures of neuropathic severity in 15 diabetic patients with mild neuropathy and 14 control subjects. Diabetic patients demonstrated a significant (P < 0.01) reduction in myelinated fibre density, but no change in fibre/axonal area, or g-ratio, compared to control subjects. Unmyelinated fibre degeneration was evidenced by an increase in the percentage of unassociated Schwann cell profiles (P < 0.0001) and a reduction in axon density (P < 0.0008) in diabetic patients. This was associated with a significant reduction in unmyelinated axon diameter (P < 0.001) with a shift of the size frequency distribution to the left (P < 0.02). Neurophysiology, quantitative sensory testing and nerve fibre pathology failed to differentiate diabetic patients with painful and painless neuropathy and failed to correlate with any measure of unmyelinated fibre pathology.

Audio-vestibular manifestations of Chiari malformation and outcome of surgical decompression: a case report.

Sensorineural hearing loss, tinnitus, dizziness and ataxia are recognised symptoms associated with Chiari malformations but they are rarely the presenting complaints. Patients with such symptoms are frequently referred to otolaryngologists and audiological physicians. We report a case of a 13-year-old girl who presented complaining of tinnitus and impaired hearing, and was subsequently diagnosed as having a type I Chiari malformation. Pure tone audiogram showed a mild hearing impairment on the left side and the speech audiogram was normal. Auditory brain stem responses and the electronystagmography were abnormal. The patient underwent posterior fossa decompression following which her tinnitus disappeared, the hearing problem recovered and some of the abnormal electrophysiological parameters were corrected.

Variation of expression of the gene for type 2 neurofibromatosis: absence of a gender effect on vestibular schwannomas, but confirmation of a preponderance of meningiomas in females.

Type 2 neurofibromatosis is a dominantly inherited disorder in which the great majority of sufferers develop bilateral vestibular schwannomas. In a UK study of 183 individuals from 112 families we have previously shown a fairly similar disease course within families, but quite marked inter-familial variation. We have confirmed an increase in severity when the gene is inherited from an affected mother, but evidence that women are more severely affected than men is lacking. Age at onset of symptoms, of deafness and at diagnosis are identical for the entire dataset and for a comparison of 10 male/female sibling pairs. Only three out of 42 pregnancies in symptomatic women were accompanied by a reversible worsening in symptoms due to vestibular schwannomas. Of 328 consecutive cases of unilateral vestibular schwannoma, there was no significant difference in the sex ratio or size. There now appears to be little evidence for a female hormonal effect on vestibular schwannomas. However, females with type 2 neurofibromatosis have significantly more meningiomas.

Magnetic resonance imaging: a cost-effective first line investigation in the detection of vestibular schwannomas.

Magnetic resonance imaging (MRI) is currently the 'gold-standard' investigation in patients with a unilateral sensorineural hearing loss. The procedure, however, is expensive and of limited availability. Instead, such patients often undergo a series of audiovestibular tests and computed tomography in an attempt to exclude or diagnose a vestibular schwannoma. We describe seven cases of unilateral vestibular schwannoma in which conventional assessment was either equivocal or failed to demonstrate a tumour subsequently diagnosed by magnetic resonance imaging. Two patients with neurofibromatosis type 2 are also reported to show how magnetic resonance imaging confirmed the presence of a second vestibular schwannoma despite CT that showed only a unilateral lesion. We also illustrate how limited protocol MRI of patients is slightly more expensive yet much more cost effective than the usual battery of tests and propose that it should be the first line investigation for patients in whom the clinical picture requires exclusion of a retrocochlear lesion. Not all of these early diagnosed tumours have been immediately removed. In some of the more elderly or infirm patients a 'wait and rescan' policy has been adopted. Nevertheless, the early establishment of the correct diagnosis facilitates the subsequent management of these patients.

A clinical, genetic and audiological study of patients and families with bilateral acoustic neurofibromatosis.

The neurofibromatoses consist of at least two distinct autosomal dominant hereditary disorders. Neurofibromatosis type 1 (NF1) is due to a lesion on chromosome 17q. Neurofibromatosis type 2 (NF2) is caused by a defect on chromosome 22q. The hallmark of NF2 is the development, in the second and third decades, of bilateral acoustic neuromas. NF1 is characterized by the appearance of café-au-lait spots and neurofibromas in addition to iris hamartomas, or Lisch nodules, of the eye, during the first and second decades. Ten families were personally studied. A total of 16 members were found to be affected with NF2. A protocol for evaluation and review of subjects and relatives of NF2 families is proposed. A team approach, coordinating the expertise of multiple specialties is recommended.

Ionomeric bone cement in neuro-otological surgery.

The use of a polymaleinate glass ionomer cement in 80 neuro-otology cases is described. It has proved of great value in translabyrinthine acoustic neuroma surgery, reducing the incidence of CSF fistula to nil. It is the method of choice for fixation of the Nucleus cochlear implant, and has many other applications in the field of otology and neuro-otology. It is easy to use and appears to have no side effects.

Endoneurial capillary abnormalities in mild human diabetic neuropathy.

Microvascular factors have been implicated in the pathogenesis of human diabetic neuropathy. The extent of microangiopathy was assessed in 15 diabetic patients with clinically mild neuropathy and compared with eight age matched control subjects. Endoneurial capillary density was reduced (p less than 0.04) and correlated significantly with reduced myelinated fibre density (p less than 0.01). Both basement membrane area (p less than 0.0001) and endothelial cell profile number per capillary (p less than 0.002) were significantly increased in diabetic patients and correlated significantly with both neurophysiological and neuropathological measures of neuropathic severity. There was no evidence of endothelial cell hypertrophy as assessed by either cross sectional endothelial cell area or a reduction in luminal size. Furthermore, the percentage of closed vessels did not differ between diabetic patients and control subjects and failed to relate to measures of neuropathic severity. It was concluded that microvascular abnormalities are prominent in patients with clinically mild human diabetic neuropathy, and that these data provide further support for the role of endoneurial capillary disease in the development of this condition.

Criteria for hearing preservation in acoustic schwannoma surgery: the concept of useful hearing.

In the quest for hearing preservation in patients with acoustic schwannomas it is essential that surgeons do not lose sight of the concept of 'useful' hearing. There is an important difference between hearing preservation which pleases the surgeon and that which will be appreciated by the patient. Tumour size, pure tone audiogram average differences between ears and speech discrimination scores have been recorded in a series of 114 patients with unilateral acoustic schwannomas. Criteria for useful hearing are presented in terms of pure tone audiogram average difference and speech discrimination scores. There were 11 patients (10 per cent) with a speech discrimination score of 50 per cent or more, a pure tone audiogram average difference of 30 dB or better and a tumour size of no more than 2 cm. Only one patient (0.9 per cent) had a speech discrimination score of 50 per cent or more, a pure tone audiogram average difference of 20 dB or better and a tumour size of no more than 1 cm. It is concluded that hearing preservation techniques may be applicable to between 1 and 10 per cent of patients with unilateral acoustic schwannomas.

The fate of tumour rests following removal of acoustic neuromas: an MRI Gd-DTPA study.

The fate of capsular fragments left attached to vital structures at the time of otherwise total tumour removal was studied in 14 of 21 such patients who underwent acoustic neuroma surgery. Imaging using magnetic resonance Gd-DTPA at post-operative intervals of 6 months-12 years (mean 70 months) showed evidence of persistent tumour in half the patients. None of the patients had developed new symptoms and computed tomography had failed to demonstrate tumour recurrence. Persistence of the tumour was more likely if the residual fragments were not cauterized at the time of operation. Four of the seven persisting tumour rests showed evidence of gradual enlargement. The implications for patient management, particularly if an attempt is made to preserve hearing, are discussed.

Choroid plexus papilloma of the cerebellopontine angle.

We report a case of a transdural choroid plexus papilloma of the cerebellopontine angle in a 23-year-old woman. Choroid plexus papillomas are rare intracranial tumors, usually occurring intraventricularly. Those found in the cerebellopontine angle are uncommon and almost always subdural. The investigation, treatment, and follow-up are discussed.

The relationship between sural nerve morphometric findings and measures of peripheral nerve function in mild diabetic neuropathy.

The morphological findings in sural nerve biopsy specimens from 15 diabetic patients with mild neuropathy were compared with control biopsies from eight non-neuropathic, non-diabetic subjects, and correlations were sought with electrophysiological studies and quantitative sensory tests for vibration, thermal, and current perception thresholds. Myelinated fibre density was reduced compared with control biopsies (4042 +/- 2090 (+/- SD) vs 6800 +/- 1100 mm-2; p less than 0.01). A strong correlation existed between myelinated fibre density and sural sensory conduction velocity (r = 0.84, p less than 0.001), sural action potential amplitude (r = 0.74, p less than 0.001), peroneal motor conduction velocity (r = 0.58, p less than 0.02), and median sensory amplitude (r = 0.64, p less than 0.01) but there was no correlation between myelinated fibre density and any quantitative sensory test. We conclude that conventional electrophysiological tests in the lower limb are reliable surrogate measures for structural abnormalities in early diabetic neuropathy.

Raised levels of latent collagenase activating angiogenesis factor (ESAF) are present in actively growing human intracranial tumours.

Endothelial cell stimulating angiogenesis factor (ESAF) is a potent, low molecular mass mitogen, specific for endothelial cells. In common with various protein growth factors, it displays angiogenic activity in a variety of biological test systems. However, it differs from these other factors by virtue of its low molecular mass and its ability to activate latent matrix metalloproteinases in a dose dependent manner. This activity has been used to quantify the factor in both normal and diseased brain tissue. The concentration of ESAF determined in biopsies from different types of intracranial tumours varied: in some tumour types the level was close to that of control samples whereas in others it rose to levels comparable to those encountered in the pineal gland, the richest source of ESAF in mature mammals. Tumours considered to be benign contained significantly less ESAF than those neoplasms classified as being malignant (P = 0.025). There was also a correlation between the mitotic activity of tumour samples, as determined by conventional H & E histochemical staining and the ESAF concentration present. These findings agree with previous studies in which elevated ESAF levels have been found in tissue where proliferation of vascular elements has been observed.

Acoustic neuroma (schwannoma) surgery 1978-1990.

A series of 151 patients with 154 acoustic schwannomas have been operated upon in Manchester Royal Infirmary by a joint Otological and Neurosurgical team, employing either the translabyrinthine or the suboccipital approach. The perioperative mortality rate was 3 per cent. Anatomical preservation of the facial nerve was achieved in 89 per cent of tumour removals and a good to normal functional result in 79 per cent of cases. Attempts at hearing preservation have been unsuccessful, largely because of the small number of patients in the series in whom useful hearing was present preoperatively. Complications included major brain stem ischaemia (1.2 per cent), CSF fistula (5 per cent) and facial dysaesthesia (7 per cent). The incidence of mortality and morbidity is directly related to tumour size and to the experience of the surgeons. A number of patients experienced an unusual type of post-operative dreamlike state which appeared to be a form of hypnagogic hallucination, and the possible neurophysiological mechanism responsible for this phenomenon is discussed. The continuing failure to attain the ideal of early diagnosis is lamented, and the importance of a flexible bidisciplinary surgical approach emphasized.

Haemangiopericytoma of the temporal bone.

Haemangiopericytoma is an uncommon vascular tumour with a widespread distribution. Although meningeal involvement is well recognized, only a few sporadic cases of temporal bone lesions have been documented, all with doubtful sites of origin. Late presentation together with the restrictive anatomy of this region often precludes its effective removal and even minimal residual disease may progress rapidly. A series of three such patients are presented in order to discuss the natural history, histological features and treatment of this disease.

Oestrogen and progesterone receptors in acoustic neuroma.

Tissue samples from fourteen consecutive (8 male: 6 female) acoustic neuromas were assayed for hormone receptors using either a monoclonal antibody (MA), dextran coated charcoal (DCC) or isoelectric focusing (IEF) technique. In this series there were no unequivocally positive results, a finding at variance with previously published results.

Spontaneous dissection of the intrapetrous internal carotid artery.

Two cases of cervicocephalic arterial dissection of the intrapetrous carotid artery are described. One patient presented with intolerable objective pulsatile tinnitus, the other with a cerebral infarction. Both were successfully treated with anticoagulants. The significance of minor degrees of trauma and of neck extension in the aetiology of these apparently spontaneous lesions is discussed.

Hypoxic neuropathy: relevance to human diabetic neuropathy.

Clinical and neurophysiological studies were conducted in 47 patients with chronic obstructive airways disease and compared with 46 age-matched control subjects. Symptomatic neuropathy was reported in 13% and ankle jerks were absent in 45% of hypoxic patients. Peroneal and median nerve conduction velocities and median and sural sensory nerve amplitudes were significantly reduced in hypoxic patients (p less than 0.01). Six hypoxic patients underwent biopsy of the sural nerve, soleus muscle and overlying skin. Nerve glucose, sorbitol, fructose and myo-inositol concentrations were normal. Detailed light and electronmicroscopy revealed both nerve fibre and microvascular pathology. Segmental demyelination (32%) and unmyelinated fibre degeneration were found to be prominent lesions. The sural nerve perineurium was thickened due to an increase in the number of perineurial lamellae and an increase in intraperineurial space. Basement membrane thickening was observed in capillaries of nerve, muscle and skin. Endothelial cell hyperplasia and hypertrophy were observed in nerve and muscle capillaries but not in skin capillaries. In conclusion, this study has provided neurological, neurophysiological and neuropathological evidence of a neuropathy in hypoxic patients with chronic obstructive airways disease. These findings may be of relevance to some aspects of the aetiology of human diabetic neuropathy.

The surgical management of intracranial tumours.

Surgery may contribute significantly to the management of intracranial neoplasms. It helps establish the diagnosis and provides palliation or even cure in selected cases. This article evaluates the present role of surgery, details some of the techniques involved with their associated complications and gives the expected outcome for certain types of tumour.

Are HLA antigens implicated in the pathogenesis of non-haemorrhagic deterioration following aneurysmal subarachnoid haemorrhage.

Aneursymal subarachnoid haemorrhage is frequently complicated by non-haemorrhagic deterioration. HLA typing was studied in a group of 40 patients who had sustained an aneurysmal subarachnoid haemorrhage in order to assess its ability to identify those who are likely to experience non-haemorrhagic deterioration. The antigen HLA-B7 appeared to be associated with an increased likelihood of this event supervening. Conversely, the antigen HLA-DR3, seemed to exert a "protective" influence.