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Biomedical subjects

G Neil-Dwyer

Publications and source records attributed to G Neil-Dwyer.

At least 37 records · Page 2Linked to original sources
PubMed1999

The extended transbasal approach: clinical applications and complications.

OBJECTIVES: To describe in detail key technical aspects of the extended transbasal approach which involves en-bloc mobilisation of the supraorbital rim, the orbital roof and the nasoethmoidal complex. In some patients osteotomies were performed around the cribriform plate with a view to maintaining olfaction. To review 18 patients with deep seated lesions located in the central skull base region (including 6 recurrences) to highlight patient selection, presentation, surgical morbidity and outcome. METHODS: Prospective data recording and clinical chart review. RESULTS: Outcome was assessed at a minimum of 1 year after operation using the Glasgow Outcome Score. Thirteen patients had made a good recovery, 1 was moderately disabled, 2 were severely disabled (both had been severely disabled before operation), and 2 died. By contrast, quality of life assessment indicated that only 7 of the surviving 14 adults had returned to normal levels of activity and perceived health; although 6 of the other 7 patients had resumed their former occupations, their follow up assessments showed a reduced quality of life. Of the 13 patients who had an olfaction preservation procedure, 6 showed appreciation of smell on formal testing. CONCLUSIONS: In patients with progressive and extensive deep seated lesions this technique provides wide exposure in a shallow surgical field. Complication rates although acceptable were significantly higher in patients with intradural lesions. In some selected patients it was possible to preserve olfaction. Specific surgical outcome assessments pointed to satisfactory results, but failed to reflect the degree of patient disability. There is a need for outcome measures that take into account the patient's expectations and which address his quality of life in order to validate the benefits of these procedures.

Adolescent↗
PubMed1999

Outcome after complex neurosurgery: the caregiver's burden is forgotten.

OBJECT: The goals of this study were twofold: 1) to determine outcome, including quality of life, in patients who have undergone surgery for petroclival meningioma in which a standard skull base approach was used; and 2) to assess the impact of the patients' surgical treatment on their caregivers. METHODS: Seventeen patients (13 women and four men ranging in age from 29 to 63 years) who underwent a transpetrosal approach for a petroclival meningioma during a 5-year period were prospectively included in this study. Pre- and postoperative data including adverse events were noted. The patients were assessed at 3, 6, and 12 months postoperatively, and annually thereafter, and they completed a postoperative SF-36 questionnaire. In addition, each patient's caregiver was interviewed to determine the effect of the patient's illness on the caregiver's life and responsibilities. Twenty-two operations were performed. A new permanent neurological deficit developed in five patients and in eight a temporary deficit or exacerbation of existing deficits occurred. Two patients underwent surgery to create a facial-hypoglossal nerve communication; five required a temporary percutaneous gastrostomy and/or tracheostomy; three required a shunt; and one underwent successful squint surgery. At 1 year postoperatively 13 patients had made a good or moderate recovery, three were severely disabled, and one had died--outcomes in keeping with other studies. By contrast, responses to the SF-36 questionnaire showed that, in all eight of its categories, between 43% and 75% of surviving patients were functioning below accepted norms. Fifty-six percent of caregivers experienced a major change in lifestyle and 38% experienced a major change with respect to their work. CONCLUSIONS: After transpetrosal excision of a petroclival meningioma, the quality of life for the patient is worse than that indicated in surgeons' reported results. The impact on the patient's caregiver is profound-a burden perhaps not fully appreciated by the surgeon.

Adult↗
PubMed1998

Craniofacial access in children.

We have used craniofacial access in 20 children (age range 3/12-14 years) for complex skull base/intracranial pathology over the past 5 years. The majority of the patients had a tumour-7 of the skull base, 5 extensive suprasellar lesions and 3 acoustic neuromas; 4 had an aneurysm or AVM and in 1 there was a congenital problem. This extended application of established adult techniques in a paediatric practice emphasises the fundamental point that the quintessence of good surgical practice is the construction of an operation for the individual patient's pathology. We therefore used transzygomatic, orbital, transoral, transmandibular, petrous, transcondylar, translabyrinthine and transbasal access techniques. Good function and cosmesis with minimal complications were achieved. We have not observed complications with craniofacial growth and the majority of patients were able to return to normal school. The range of approaches used emphasise the importance of a multidisciplinary team with both paediatric and neurosurgical expertise, especially with complex vascular and skull base pathology, in dealing with these difficult problems. The case for specialist referral merits some discussion within the representative bodies of paediatric neurosurgeons.

Adolescent↗
PubMed1998

Outcome after aneurysmal subarachnoid haemorrhage: the use of a graphical model in the assessment of risk factors.

In 102 consecutive prospectively identified patients with subarachnoid haemorrhage (SAH) we have analysed the severity of the initial haemorrhage and the direct and indirect effects of adverse factors on outcome. The data we recorded included delay in diagnosis, risk groups, Doppler measurements, angiographic findings, surgical events and outcome at 1 year. By using a temporal graphical chain model, the associations between all variables and possible causal pathways were statistically determined. The severity of the initial haemorrhage, as determined by means of a clinical assessment and CT scanning, allowed low-, medium- and high-risk patient groups and a statistically predictable outcome to be identified. The overall management mortality was 13.7% at 1 year; 70.6% had a favourable outcome and 15.7% were severely disabled. Outcome was directly associated with risk group (p = 0.0038) and rebleeding (p = 0.0000). Delayed diagnosis led to a poorer outcome (p = 0.014)--an indirect association probably due to rebleeding. Adverse surgical events led to a significantly poorer outcome in high-risk patients. No significant relationship was found either between age and risk group (p = 0.7784) or between age and outcome (p = 0.6418). Preoperative clinical (WFNS) grade was unreliable in predicting outcome. It is the particular risk group, determined by the initial SAH, that indicates the individual patient's outcome. Management strategies can reduce preventable adverse events such diagnostic delay and rebleeding. Future studies should stratify patients according to risk group, delay in diagnosis and rebleeding in order to enable a clearer comparison to be made of treatment methods.

Adult↗
PubMed1997

Can we define or measure manual skills in surgical training?

Neurosurgery requires manual dexterity. But should tests be devised to assess manual skills as part of a selection process for training or used as a means of determining surgical competence? The paper debates this fundamental question and proposes that manual skills for neurosurgical tasks need to be defined within the overall context of a recognised and fully assessed training programme. The importance of training as a means of transferring competence, part of which is manual skills, is emphasised. In conclusion the paper points out the inadequacy of solely measuring manual skills, were it possible, in assessing neurosurgical competence.

Clinical Competence↗
PubMed1997

The effect of orbitozygomatic access for ruptured basilar and related aneurysms on management outcome.

BACKGROUND: Despite increasing use of craniofacial access for complex intracranial and skull base pathology, there have been no reports detailing the impact of improved access on clinical outcome. METHODS: Orbitozygomatic access was used in 32 patients with an aneurysm of the basilar bifurcation, superior cerebellar, or posterior cerebral arteries over a 9-year period. RESULTS: Operative mortality was 0%, overall management mortality 9% and management morbidity was 9%. This approach was selected for these patients because of the anatomy of the aneurysm and its relationship to the terminal basilar complex and the dorsum sellae/posterior clinoid process. The flexibility achieved by the access allowed intraoperative use of multiple corridors of access. Morbidity directly attributable to the use of orbitozygomatic access was minimal. CONCLUSIONS: While management outcome after aneurysmal subarachnoid hemorrhage relates directly to the severity of the initial hemorrhage, rather than the surgical approach chosen, in selected patients we recommend the use of this approach as a valuable adjunct to the armamentarium of the vascular neurosurgeon.

Adult↗
PubMed1997

The transzygomatic approach: an anatomical study.

The transzygomatic approach has been utilised to facilitate neurosurgical access to the skull base for a number of years. Advocates of the technique claim the additional access gained provides wider exposure of the neurosurgical pathology and improved visualisation of adjacent vital neurovascular structures. The aim of this study was to photographically demonstrate the technique and to highlight the anatomical areas to which access can be improved. A morphological cadaver study was undertaken. Specific intracranial structures in the vicinity of the skull base were targeted and exposure was compared with and without the zygoma in position. This study demonstrates the increase in exposure of the basilar bifurcation (via a transsylvian approach) and the P2 segment of the posterior cerebral artery (via a subtemporal approach) that can be achieved and the improved access to adjacent anatomical compartments. It can be concluded that the transzygomatic approach is a relatively simple technique which can readily increase exposure of the skull base. It also provides simultaneous access to the superior pole of the infratemporal fossa, the pterygopalatine fossa and the orbit.

Basilar Artery↗
PubMed1997

A nationwide study to investigate current opinion amongst maxillo-facial and neurological surgeons with regard to access surgery for neurosurgical procedures.

Over the past two decades there has been much interest in the use of craniofacial disassembly techniques to improve difficult access to some neurosurgical lesions, However, it is not known to what extent these techniques have been adopted throughout the UK. The aim of this study was to establish how many maxillofacial surgeons and neurosurgeons are currently involved in this type of collaborative surgery and to determine current opinion regarding the use of these procedures. A self-completion questionnaire was sent to all consultant maxillofacial surgeons and neurosurgeons within the UK. The results of the questionnaire suggest that there is a high level of interest in this type of collaborative surgery within the UK. It has demonstrated some interesting differences of emphasis regarding possible advantages and disadvantages of these procedures, and the areas to which access can be particularly improved. In addition, the future of this type of collaborative surgery and some of the difficulties involved in its organization were highlighted.

Attitude of Health Personnel↗
PubMed1996

The orbitozygomatic infratemporal fossa approach: a quantitative anatomical study.

Using detailed cadaveric dissections this study has demonstrated and quantified the increase in exposure and additional access gained by using the orbitozygomatic infratemporal fossa approach for neurosurgical access. The surgical window of exposure can be increased by up to 300% when this technique is utilised to facilitate access via either a subtemporal (to access the P2 segment of the posterior cerebral artery) or transsylvian (to access the basilar bifurcation) approach. In addition the distance between the surgeon and the operative field can be decreased by approximately 2-3 cm. The orbitozygomatic infratemporal fossa approach is a relatively simple technique which can readily increase neurosurgical exposure of the skull base. It also provides simultaneous access to the infratemporal fossa, pterygopalatine fossa and the orbit.

Craniotomy↗
PubMed1995

The transzygomatic approach: a long-term clinical review.

The transzygomatic approach has been utilised to improve access to the skull base, infratemporal fossa and orbit for a number of years. It provides a low anterolateral approach to the skull base, along the floor of the middle fossa. It allows both a transsylvian and subtemporal approach with a reduction in brain retraction and better exposure of adjacent neurovasculature structures. A long term review of 53 patients is presented highlighting outcome at two years post surgery and morbidity of the approach. It is concluded that the technique is versatile and can be used to improve exposure of a variety of anatomical locations. There is minimal long term morbidity attributable to the surgery of access and the majority of patients have had good outcomes.

Adolescent↗
PubMed1995

Craniofacial osteotomies for skull base access.

During a five year period 150 craniofacial access osteotomies for skull base access have been performed allowing direct exposure of pathology in difficult anatomical acreas with minimal complications. These approaches have been developed by considering the craniofacial skeleton as a single osteoplastic structure. Bone segments are mobilised and replaced using rigid fixation. In this way osteotomies can be planned which significantly improve access and preserve form and function in the complex region of the skull base.

Adult↗
PubMed1995

Assessment of autoregulation by means of periodic changes in blood pressure.

BACKGROUND AND PURPOSE: The aim of this study was to test the hypothesis that the phase difference that occurs between an induced oscillation in blood pressure and the resultant oscillation in middle cerebral artery (MCA) flow velocity could reflect the competence of cerebral autoregulation. METHODS: Fourteen volunteers performed 19 cycles of 10 seconds of squatting followed by 10 seconds of standing. Peak MCA velocity was measured with transcranial Doppler ultrasound, and blood pressure was measured with a servo-controlled finger plethysmograph held level with the head. Waveforms from each cycle were added to obtain averaged waveforms of arterial blood pressure and MCA velocity. These results were processed by Fourier analysis to extract the phase difference between the fundamental components of velocity and pressure. Each volunteer performed the exercise three times: first breathing normally, secondly hyperventilating (hypocapnia), and finally while breathing air containing 5% carbon dioxide (hypercapnia). Under these conditions the volunteers were expected to have normal, enhanced, and impaired auto-regulation, respectively. RESULTS: The measurements made with normal breathing showed a phase lead of velocity ahead of pressure of 46 +/- 14 degrees (mean +/- SD). We noted a highly significant reduction in phase lead with hypercapnia (P < .00015) (Wilcoxon signed rank test, two-tailed) and a highly significant increase in phase lead with hypocapnia (P < .002). CONCLUSIONS: The results support our hypothesis and may lead to a technique for assessing the competence of cerebral autoregulation.

Adolescent↗
PubMed1994

A multidisciplinary approach to tumours involving the orbit: orbital re-construction, a 3-dimensional concept.

Radical tumour removal in the region of the anterior skull base with involvement of the orbit requires not only good exposure but also acceptable reconstruction with good cosmesis, no visible scars and no injury to the eye. The possible approaches, which should be flexible and adapted to the location and extent of the pathology and the appropriate methods of reconstruction, are illustrated by four patients. The relevant literature is reviewed. Emphasis on the need for a 3-dimensional concept in the reconstruction and the importance of a multi disciplinary team is stressed.

Adult↗
PubMed1994

Delayed cerebral ischaemia: the pathological substrate.

Ischaemic complications both at the level of the cortex and the hypothalamus are well recognised after an aneurysmal subarachnoid haemorrhage. We have studied histological changes in the cortex (53 patients) and hypothalamus (48 patients) in patients who died after an aneurysmal subarachnoid haemorrhage. Cortical ischaemic lesions were demonstrated in 41 of the 53 patients studied. These changes were more common in patients who had impaired control of systemic blood pressure (p = 0.0004) and in patients who died gradually (p = 0.0003). Hypothalamic lesions were found in 24 of 48 patients studied; 23 of these patients had widespread associated changes in the cerebral cortex. Patients with moderate/severe cortical changes tended to have hypothalamic lesions and it was uncommon for patients with no cortical lesions to have changes in the hypothalamus (p = 0.0007). We believe that these histological changes are due to diffuse microangiopathy which develops slowly after a subarachnoid haemorrhage and affects the cortex and hypothalamus. Because the cortical lesions are widespread we postulate that they may be implicated in the aetiology of the well described psychosocial or cognitive problems in patients who survive a subarachnoid haemorrhage.

Adult↗