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Dive into the research topics where Timothy Steel is active.

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Featured researches published by Timothy Steel.


Neuropathology and Applied Neurobiology | 2000

Skull base chordomas: correlation of tumour doubling time with age, mitosis and Ki67 proliferation index

Janice L. Holton; Timothy Steel; M. Luxsuwong; Ha Crockard; Tamas Revesz

The aim of the study was to assess the relationship between the rate of clinical tumour growth and various histological features, including Ki67 labelling index, in skull base chordoma. Cases of skull base chordoma from 19 patients (six female, 13 male; age range 8–63 years) were reviewed and the diagnosis confirmed based on histological and immunohistochemical features. In each biopsy cellularity, pleomorphism, mitotic activity, apoptotic bodies, necrosis and inflammatory cell infiltrate were graded and Ki67 labelling index (LI) calculated as a measure of proliferation. Tumour doubling time was assessed by quantitative analysis of tumour volumes in post‐operative magnetic resonance images and correlated with age, sex, histological parameters and Ki67 LI. It was shown that increasing patient age, the presence of mitotic figures or a Ki67 LI in excess of 6% were associated with faster growing tumours.


Neurosurgery | 1993

Paragangliomas of the sellar region: Report of two cases

Timothy Steel; Andrew T. Dailey; Donald E. Born; Mitchel S. Berger; Marc R. Mayberg

Two cases of paraganglioma arising from the parasellar region are presented. Both occurred in middle-aged women who sought treatment of headaches but who had no endocrinological dysfunction; one case was associated with ophthalmoplegia from cavernous sinus involvement. Diagnosis in both cases was confirmed by typical histological appearance and cytochemical demonstration of immunoreactive chromogranin in tumor cells. The pathological features and possible pathogenesis of parasellar paragangliomas are discussed.


Neurosurgery | 1993

Paragangliomas of the Sellar Region

Timothy Steel; Andrew T. Dailey; Donald E. Born; Mitchel S. Berger; Marc R. Mayberg

Two cases of paraganglioma arising from the parasellar region are presented. Both occurred in middle-aged women who sought treatment of headaches but who had no endocrinological dysfunction; one case was associated with ophthalmoplegia from cavernous sinus involvement. Diagnosis in both cases was confirmed by typical histological appearance and cytochemical demonstration of immunoreactive chromogranin in tumor cells. The pathological features and possible pathogenesis of parasellar paragangliomas are discussed.


Journal of Clinical Neuroscience | 2010

A rosette-forming glioneuronal tumour of the pineal gland

Ellen Frydenberg; R. Laherty; M. Rodriguez; M. Ow-Yang; Timothy Steel

A rosette-forming glioneuronal tumour (RGNT) is a rare tumour with new information emerging. We review the literature and describe the second patient with a RGNT arising from the pineal gland. This is also the fifth report of a RGNT arising from outside the fourth ventricle. The prognosis of RGNT remains guarded, as long-term follow-up is not yet available for most patients reported. With only one of 35 patients having a documented recurrence at 10 years, the prognosis seems favourable with appropriate, but not necessarily total, surgical resection.


Journal of Clinical Neuroscience | 2007

Migration of lumbar disc herniation: An unusual case

Ralph J. Mobbs; Timothy Steel

We illustrate a patient with a migrating lumbar disc fragment that caused a change in radicular symptoms from the L3 nerve root on one side to the L5 nerve root on the contralateral side, documented by magnetic resonance imaging (MRI). Our patient presented with 3 months of L3 pain on the right side with sensory and motor changes. Over a 24-hour time period, the right leg pain disappeared and he developed left leg pain attributable to left L5 nerve root compression. Investigation with MRI revealed an epidural mass, which was hypointense on Tl-weighted and T2-weighted images that had migrated, initially compressing the right L3 nerve root, to now compress the left L5 nerve root. The patient did not wish to pursue surgery. Disc fragment migration patterns are discussed. We conclude that extruded disc fragments may migrate distant from their initial origin.


Surgical Neurology | 1994

Paraganglioma of the cauda equina with associated syringomyelia: Case report

Timothy Steel; Paull Botterill; John P. Sheehy

We present an association not previously described in which the rare entity of paraganglioma of the cauda equina was found in association with syringomyelia of the cervico-thoracic cord. The patient, a 50-year-old woman presented with a long history of lower back pain with recent onset of sciatic pain and altered sensation in the right leg. Surgical resection of the tumor with intraoperative syringostomy of the syrinx has led to eradication of all symptoms and at 5 months shows no evidence of residual pathology.


Journal of Clinical Neuroscience | 2005

CT guided aspiration of a cervical spinal epidural abscess

T.M. Rust; S. Kohan; Timothy Steel; R. Lonergan

The management of spinal epidural abscess has changed over the last few years. Originally treatment was thought to be urgent surgical evacuation. In the more recent literature less invasive techniques have been suggested. We present a case, where a cervical epidural abscess at the C2 level was treated with CT guided aspiration and antibiotic therapy. This has not been previously reported.


British Journal of Neurosurgery | 1994

Vascular neurofibromatosis affecting the internal carotid artery: a case report

Timothy Steel; Bentivoglio Pb; Raymond Garrick

A patient with von Recklinghausens disease presented with a right sixth nerve palsy. Investigations demonstrated unilateral dolichoectasia of the intracranial carotid artery and sphenoid wing dysplasia. This case demonstrates an association not previously documented, that of unilateral fusiform dilatation of the carotid artery with sphenoid wing dysplasia in the presence of classical neurofibromatosis.


Skull Base Surgery | 2015

The Olfactory Strip and Its Preservation in Endoscopic Pituitary Surgery Maintains Smell and Sinonasal Function

Richard J. Harvey; Mark Winder; Andrew Davidson; Timothy Steel; Sunny Nalavenkata; Nadine Mrad; Ali R. Bokhari; Henry P. Barham; Anna Knisely

Background The return of olfaction and of sinonasal function are important end points after pituitary surgery. Opinions differ on the impact of surgery because techniques vary greatly. A modified preservation of the so-called olfactory strip is described that utilizes a small nasoseptal flap and wide exposure. Methods A cohort of patients undergoing pituitary surgery and endoscopic sinonasal tumor surgery were assessed. Patient-reported outcomes (Sino-Nasal Outcome Test [SNOT22] and Nasal Symptom Score [NSS]) were recorded. A global score of sinonasal function and the impact on smell and taste were obtained. Objective smell discrimination testing was performed in the pituitary group with the Smell Identification Test. Outcomes were assessed at baseline and at 6 months. Results Ninety-eight patients, n = 40 pituitary (50.95 ± 15.31 years; 47.5% female) and n = 58 tumor (52.35 ± 18.51 years; 52.5% female) were assessed. For pituitary patients, NSSs were not significantly different pre- and postsurgery (2.75 ± 3.40 versus 3.05 ± 3.03; p = 0.53). SNOT22 scores improved postsurgery (1.02 ± 0.80 versus 0.83 ± 0.70; p = 0.046). Objective smell discrimination scores between baseline and 6 months were similar (31.63 ± 3.49 versus 31.35 ± 4.61; p = 0.68). No difference in change of olfaction was seen compared with controls (Kendall tau-b p = 0.46). Conclusions Preservation of the olfactory strip can provide a low morbidity approach without adversely affecting olfaction and maintaining reconstruction options.


Rhinology | 2015

Sinonasal morbidity following tumour resection with and without nasoseptal flap reconstruction.

Richard J. Harvey; Joanne Malek; Mark Winder; Andrew Davidson; Timothy Steel; Nadine Mrad; Henry P. Barham; Anna Knisely; Charles Teo

BACKGROUND Sinonasal function can be affected by multiple treatment modalities but surgical techniques, such as the nasoseptal flap or Draf 3 procedure, have been implicated in poor post-treatment function. Prior studies have rarely used comparable populations and this study aims to assess the impact of surgical technique, mainly the nasoseptal flap, on sinonasal function in a group of comparable patients. METHODS A prospective cohort of patients undergoing endoscopic surgery for sinonasal and skull base tumours was studied. Patients were analysed according to whether a nasoseptal flap was used. Other treatment factors included; use of the Draf 3, radiotherapy, removal of olfactory apparatus and dural resection. The Sinonasal Outcome Test 22 (SNOT22), a nasal symptom score (NSS), global function score and nasal obstruction scores were recorded pre and post treatment. RESULTS One hundred and eighteen patients were assessed. Forty-two patients had a nasoseptal flap. Perioperative radiotherapy was higher in the nasoseptal group, as was dural resection and the need to remove the olfactory apparatus. Despite this, there was no significant difference in SNOT22 scores and NSS. Radiotherapy was detrimental to sinonasal function with SNOT22 and NSS. CONCLUSION The use of a nasospetal flap in surgery does not affect patient quality of life and sinonasal function after endoscopic tumour resection. Pathology is a better predictor of morbidity, with loss of function from radiotherapy or resection of functional areas such as the olfactory apparatus having a greater impact.

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Ellen Frydenberg

St. Vincent's Health System

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Tamas Revesz

UCL Institute of Neurology

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Richard J. Harvey

University of New South Wales

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Donald E. Born

University of Washington

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M. Ow-Yang

St. Vincent's Health System

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Mark Winder

St. Vincent's Health System

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