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Biomedical subjects

H B Coakham

Publications and source records attributed to H B Coakham.

At least 19 recordsLinked to original sources
PubMed2005

Patient satisfaction after surgery for trigeminal neuralgia--development of a questionnaire.

OBJECTIVE: This project aimed to prepare a self complete patient satisfaction survey for patients who have undergone surgery for trigeminal neuralgia and then assess its reproducibility, validity and acceptability in one centre. METHODS: The questionnaire, for initial use in patients who had undergone posterior fossa surgery for trigeminal neuralgia, was designed after a systematic review of the surgical literature had been performed and discussions held at the US and UK Trigeminal Neuralgia Support group meetings. It underwent several changes after input from neurosurgeons, patients, copywriter and statistician and finally contained 44 questions, the SF12, Hospital Anxiety and Depression Scale (HAD), Brief Pain Inventory (BPI) and McGill Pain questionnaire (MPQ). From the total number of 413 patients in the database of one centre the questionnaire was sent with a covering letter to 305 patients, the rest had died (25), were lost to follow up (26) or did not meet the inclusion criteria (56). One patient had bilateral PSR. The completed questionnaires were evaluated by an independent physician, neurosurgeon and patient. A repeat questionnaire was sent to 10% of the patients to check reproducibility. RESULTS: The questionnaires were well completed with a final response rate of 92%. It appeared to be highly acceptable and reproducible but needed adjustment to improve its validity before being used in other centres and for all surgical procedures. A new questionnaire is proposed which could be used on an annual basis. CONCLUSIONS: A questionnaire has been developed for use in patients who have undergone surgical management for trigeminal neuralgia and which is acceptable to patients.

Decompression, Surgical↗
PubMed2005

Cryptic cerebellopontine angle neuroglial cyst presenting with hemifacial spasm.

Hemifacial spasm (HFS) is commonly caused by a vascular loop compressing the Root Exit Zone (REZ) of the facial nerve. We report a case of HFS caused by a vascular loop that was abnormally displaced by a neuroglial cyst not seen in Magnetic Resonance Imaging (MRI). Microvascular decompression (MVD) was planned and the patient underwent a key-hole retromastoid posterior fossa exposure. A cystic lesion was found in the cerebellopontine angle (CPA), located around the seventh and eighth cranial nerves extending from the porous acousticus to the brainstem REZ of the facial nerve. The cyst wall was partially excised revealing the region of the neurovascular conflict. MVD of the facial nerve was performed with immediate postoperative complete resolution of the patient's symptoms.

Adult↗
PubMed2005

Some patients with multiple sclerosis have neurovascular compression causing their trigeminal neuralgia and can be treated effectively with MVD: report of five cases.

The role of trigeminal ganglion percutaneous injection and radio-frequency lesioning procedures for the treatment of trigeminal neuralgia (TGN) in multiple sclerosis (MS) is well established. There is general acceptance that microvascular decompression (MVD) cannot be an appropriate treatment due to the view that the underlying aetiology is a demyelinating plaque affecting the root entry zone of the trigeminal pathway. Recently, MR-imaging has been used in the preoperative investigation of this group of patients demonstrating that neurovascular compression can occasionally be the responsible mechanism and that MVD can be the treatment of choice. We present five cases with MS and TGN. All the patients had failed to respond to medical treatment or percutaneous procedures. Magnetic resonance imaging demonstrated evidence of neurovascular compression in four cases. All the patients underwent MVD. Postoperatively four of the five patients made an uncomplicated recovery, were pain-free and fully satisfied with the result (mean follow-up 38.75 months; range 8-59 months). One patient developed recurrent pain 1 week following surgery and went on to have a total sensory rhizotomy. TGN in MS can be caused by neurovascular compression, which may be identified on MR-imaging. MVD has offered satisfactory short-term outcome for at least 2 years and does not inflict sensory loss. Longer follow-up will determine whether the outcome in MS patients will be as successful as in the TGN patients who do not suffer from MS.

Adult↗
PubMed2005

Malignant transformation of posterior fossa epidermoid cyst.

The authors report the case of a 45-year-old man who presented with a short duration of a painful ophthalmoparesis. Initial magnetic resonance imaging revealed an extraaxial petroclival mass characteristic of an epidermoid cyst, with the exception of a contiguous contrast-enhancing lobule. A subtotal resection was performed with the histopathological diagnosis revealing malignant transformation of an epidermoid cyst. Despite aggressive postoperative adjuvant therapy, the patient developed leptomeningeal metastasis and died shortly thereafter. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the treating physician to the possibility of a malignant transformation. When transformation does occur, the clinical and radiological course is quite aggressive as compared with the indolent growth of epidermoid cysts. Treatment options include surgery with adjuvant chemotherapy or radiotherapy. We review the pertinent features of this case along with the relevant literature regarding primary intracranial squamous cell carcinomas.

Carcinoma, Squamous Cell↗
PubMed2003

Hearing preservation and facial nerve function in vestibular schwannoma surgery.

The objective of this study was the assessment of hearing preservation in vestibular schwannoma surgery. This study reports a prospective cohort of 40 patients with clinically useful hearing from a consecutive series of 191 patients with unilateral vestibular schwannoma. The patients were managed in a tertiary centre by a combined team of Neurosurgeon, Otologist and Neuro-monitoring Scientist via a neuro-oto-surgical-retrosigmoid approach. Pure tone speech audiometry was conducted preoperatively and 6 months to 9 years following surgery. Using the AA0-HNS classification, useful hearing, i.e. grades A, B and C, was preserved in 47.5% of patients. Thirty-eight per cent achieved grade A or B. Using appropriate surgical and monitoring techniques, it is possible to preserve useful hearing in approximately 50% of patients following removal of a vestibular schwannoma via the retro-sigmoid approach.

Adult↗
PubMed2003

How accurate is magnetic resonance angiography in predicting neurovascular compression in patients with trigeminal neuralgia? A prospective, single-blinded comparative study.

Ninety-two patients with trigeminal neuralgia (TGN) were investigated prior to posterior fossa surgery with magnetic resonance imaging (MRI) and contrast-enhanced magnetic resonance angiography (MRA). The preoperative investigation was matched to one consultant neuroradiologist (co-author) who was blinded to the side of symptomotology. The imaging results were compared with the operative findings in all patients. In 76 patients MRA showed present neurovascular compression in accordance with surgical findings. Eight cases had no compression either on MRA or intraoperatively. Eight predictions of no compression were false and there was no false positive. Based on surgical findings, the sensitivity of MRA was 90.5% and the specificity 100%. In 19 cases MRA predicted bilateral compression of the trigeminal nerves. Only two cases had clinically bilateral TGN. We conclude that MRA with gadolinium enhancement is an extremely sensitive and specific method for demonstrating compression in TGN. As a result posterior fossa surgery can be recommended with confidence, and microvascular decompression remains the treatment of choice for TGN at the authors' centre.

Contrast Media↗
PubMed2002

Episodic facial palsy due to epithelial cyst of the cerebellopontine angle: case report and review of the literature.

A case of cerebellopontine angle epithelial cyst is described. Lesions in this region usually present with hearing loss, tinnitus, dysequilibrium, headaches, facial numbness and occasionally trigeminal neuralgia. Our patient presented with the unusual phenomenon of episodic facial palsy. The literature reporting this lesion as well as this mode of presentation has been reviewed.

Adult↗
PubMed2002

Trochlear nerve schwannoma removed by combined petrosal approach.

Trochlear nerve schwannoma is an extremely rare intracranial tumour. It is a benign tumour often presenting late with the involvement of neighbouring structures and potentially life threatening complications. We report a case of this condition, which is the first to be treated by surgery via a presigmoid 'combined petrosal approach' with follow-up by magnetic resonance imaging (MRI) for 6 years. The advantages of the presigmoid combined petrosal approach for this type of tumour are described. Early investigation of patients with unexplained trochlear nerve palsy by MRI will facilitate the management of these rare tumours.

Cranial Nerve Neoplasms↗
PubMed2001

Trigeminal neuralgia due to multiple sclerosis: ultrastructural findings in trigeminal rhizotomy specimens.

Trigeminal neuralgia is a well-recognized complication of multiple sclerosis. In patients with neuralgia not responding to medical treatment or transcutaneous ablative procedures, the pain can often be treated successfully by partial rhizotomy of the trigeminal sensory root. We have examined partial trigeminal rhizotomy specimens from six multiple sclerosis patients, aged between 34 and 77 years, with intractable trigeminal neuralgia lasting between 18 months and 11 years. The rhizotomy specimens were placed in buffered glutaraldehyde immediately after resection, and subsequently processed for electron microscopy. In all cases, this revealed demyelination in the proximal (CNS) part of the nerve root, with associated gliosis and variable inflammation. A consistent feature was the presence of clusters of juxtaposed axons without intervening glial processes. Similar juxtaposition of axons was previously observed in trigeminal neuralgia due to vascular compression of the nerve root. Experimental studies indicate that this arrangement of demyelinated axons is conducive to both spontaneous impulse activity and ephaptic spread of excitation. The demyelination and associated juxtaposition of axons may therefore account for key aspects of the pathogenesis of trigeminal neuralgia.

Adult↗
PubMed2001

The role of endoscopic biopsy and third ventriculostomy in the management of pineal region tumours.

The best surgical strategy for treating patients with pineal tumours presenting with acute hydrocephalus remains undermined. During the past 17 years we have used transventricular endoscopic biopsy and third ventriculostomy as a one-step procedure in the initial management of these cases, and present the largest consecutive case series illustrating the value of this technique. We have successfully managed 34 consecutive patients with pineal region tumours, carrying out third ventriculostomy in 18 patients. Histological diagnosis was obtained in 32/34 (94%) of the cases. There were no deaths or major complications and only one patient required a ventriculo-peritoneal shunt owing to ventriculostomy failure. According to current management protocols and depending on histology, tumours were treated by a combination of resection via craniotomy followed by radiotherapy or chemotherapy, or by the latter therapies alone. This one step procedure is minimally invasive and safely achieves adequate biopsy with control of hydrocephalus, whilst definitive histology and biochemical marker studies are obtained. Definitive treatment for each tumour is designed according to diagnosis.

Adolescent↗
PubMed2001

Trigeminal neuralgia: pathology and pathogenesis.

There is now persuasive evidence that trigeminal neuralgia is usually caused by demyelination of trigeminal sensory fibres within either the nerve root or, less commonly, the brainstem. In most cases, the trigeminal nerve root demyelination involves the proximal, CNS part of the root and results from compression by an overlying artery or vein. Other causes of trigeminal neuralgia in which demyelination is involved or implicated include multiple sclerosis and, probably, compressive space-occupying masses in the posterior fossa. Examination of trigeminal nerve roots from patients with compression of the nerve root by an overlying blood vessel has revealed focal demyelination in the region of compression, with close apposition of demyelinated axons and an absence of intervening glial processes. Similar foci of nerve root demyelination and juxtaposition of axons have been demonstrated in multiple sclerosis patients with trigeminal neuralgia. Experimental studies indicate that this anatomical arrangement favours the ectopic generation of spontaneous nerve impulses and their ephaptic conduction to adjacent fibres, and that spontaneous nerve activity is likely to be increased by the deformity associated with pulsatile vascular indentation. Decompression of the nerve root produces rapid relief of symptoms in most patients with vessel-associated trigeminal neuralgia, probably because the resulting separation of demyelinated axons and their release from focal distortion reduce the spontaneous generation of impulses and prevent their ephaptic spread. The role of remyelination in initial symptomatic recovery after decompression is unclear. However, remyelination may help to ensure that relief of symptoms is sustained after decompression of the nerve root and may also be responsible for the spontaneous remission of the neuralgia in some patients. In addition to causing symptomatic relief, vascular decompression leads to rapid recovery of nerve conduction across the indented root, a phenomenon that, we suggest, is likely to reflect the reversal of compression-induced conduction block in larger myelinated fibres outside the region of demyelination. Trigeminal neuralgia can occur in association with a range of other syndromes involving vascular compression and hyperactivity of cranial nerves. Clinical observations and electrophysiological studies support the concept that demyelination and ephaptic spread of excitation underlie most, if not all, of these conditions.

Humans↗
PubMed1999

Meningiomas involving the internal auditory canal: a diagnostic and surgical challenge.

Meningiomas are the second most common lesion encountered within the cerebello-pontine angle (CPA) and rarely project into or originate from the internal auditory meatus (IAM). It is important to distinguish between meningiomas and acoustic neuromas preoperatively as the choice of surgical approach may differ depending on the tumour type. Fortunately, most lesions can be accurately diagnosed with gadolinium-enhanced magnetic resonunce imaging (MRI). We report six cases of meningioma involving the IAM, often leading to an incorrect preoperative MRI diagnosis. We highlight the challenges these tumors present to radiologists and surgeons.

Journal Article↗
PubMed1999

Intraoperative monitoring during surgery for acoustic neuroma: benefits of an extratympanic intrameatal electrode.

OBJECTIVES: To assess the utility of an extratympanic intrameatal electrode for intraoperative monitoring during acoustic neuroma and other cerebellopontine angle tumour surgery and to define the neurophysiological and surgical factors which influence hearing preservation. METHODS: Twenty two patients, 18 with acoustic neuromas and four with other cerebellopontine angle tumours, underwent intraoperative monitoring during tumour excision. The extratympanic intrameatal electrode (IME) was used to record the electrocochleogram (ECoG) and surface electrodes to record the brainstem auditory evoked response (ABR). RESULTS: The compound action potential (CAP) of the ECoG was two and a half times greater in amplitude than wave I of the ABR and was easily monitored. Virtually instant information was available as minimal averaging was required. Continuous monitoring was possible from the commencement of anaesthesia to skin closure. The IME was easy to place, non-invasive, and did not interfere with the operative field. Operative procedures which affected CAP or wave V latency or amplitude were drilling around the internal auditory meatus, tumour dissection, nerve section, and brainstem and cerebellar retraction. Hearing was achieved in 59% of patients. CONCLUSIONS: The IME had significant benefits in comparison with other methods of monitoring. The technique provided information beneficial to preservation of hearing.

Action Potentials↗
PubMed1998

Intracranial meningioma with progesterone positive receptors presenting in late pregnancy.

A 36-year-old female presented with seizures and transient dysphasia in her 31 week of pregnancy. Neuroradiological investigations revealed a large falx meningioma. A decision was taken to deliver the infant and excise the tumor before term because of the risk of an increase in the size of the tumour and the risk of sinus thrombosis. Therefore, she underwent in her 32 week of pregnancy an elective Caesarean section followed by a craniotomy to remove the meningioma. There were no neonatal complications and she made an uneventful recovery. The final pathology report confirmed the diagnosis of meningioma with progesterone positive receptors.

Adult↗
PubMed1998

Central demyelination of the Vth nerve root in trigeminal neuralgia associated with vascular compression.

We have examined the ultrastructure of the trigeminal sensory nerve root in three patients with medically intractable trigeminal neuralgia. In one patient, the nerve root was sandwiched between a large vein and a small pontine artery, in the others compression was due to marked dolichoectasia of a verterbal artery. Because these were not amenable to microvascular decompression, a caudal rhizotomy was performed, by excising a short inferior segment of nerve root in the region of indentation. In all cases, examination revealed a zone of chronic demyelination in the proximal (centrally myelinated) part of the root, near its junction with peripheral nerve. The zone of demyelination contained closely packed axons without intervening glial cytoplasm. Also present were small numbers of thinly myelinated axons. In some cases a single thin myelin sheath encircled several adjacent axons that were still in close apposition. These findings indicate that the trigeminal neuralgia associated with vascular compression is due to demyelination. The demyelination is associated with some evidence of remyelination. The latter phenomenon may account in part for the long periods of remission, especially during the initial period after the onset of trigeminal neuralgia. The partly aberrant nature of the myelination within the region of vascular compression may contribute to the persistence of symptoms in some patients after decompressive surgery.

Aged↗