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Biomedical subjects

A D Hockley

Publications and source records attributed to A D Hockley.

At least 37 records · Page 2Linked to original sources
PubMed1996

The value of colour Doppler imaging in assessing flow through ventriculo-peritoneal shunts.

So far, Doppler ultrasonography has had little application in paediatric neurosurgery. The incidental observation of normally invisible CSF flow from the peritoneal end of a ventriculo-peritoneal (V-P) shunt on colour Doppler during a conventional abdominal ultrasound examination in one of our patients suggested that colour Doppler imaging might be of potential interest. Using a 10-5 MHz broad-band linear array transducer, conventional 2D and Doppler (spectral and colour-coded) ultrasonography was performed in 17 patients with V-P shunts, who were aged 3 months to 12 years. In all, 20 examinations were performed, because 2 patients had repeat examinations before and after shunt revision. In 13 examinations (65%) CSF flow was identified through the shunt tube. Flow velocities between 5 and 7 cm/s were measured. No flow was seen in 7 examinations (35%), 3 of which (15%) were performed before revisions for a blocked shunt. Further in vitro studies with simulated shunt/ventricular system model demonstrated that although clear CSF is not ultrasonically visible, the presence of particulate matter, such as choroid plexus debris, can generate a satisfactory Doppler signal with the probe insonating over the length of the tubing. In the presence of clear CSF, turbulence generated at junction points of the shunt system or at the exit of the peritoneal tube can be visualised well with Doppler ultrasonography, presumably due to generation of microbubbles. The clinical implications for the management of shunt obstruction are discussed.

Cerebrospinal Fluid↗
PubMed1996

Paediatric meningeal tumours.

We review our experience of meningeal tumours in patients under 16 years who were treated between 1957 and 1993. These were 16 with meningiomas (median age 12 years) and 5 with poorly differentiated malignant meningeal tumours (median age 3 years). The incidence of meningeal tumours in this period was 1.62% of all CNS tumours. There were 19 supratentorial tumours (5 intraventricular), 1 tentorial and 1 cervical. Surgical excision was complete in 12 patients and incomplete in 6; in 2 patients a biopsy only was undertaken. The remaining patient had radiological diagnosis only. All 5 patients in the group with malignant poorly differentiated tumours died (median survival 5 months), confirming the aggressive nature of these lesions. Of the 16 patients with meningiomas, 4 died during followup but 11 of the 12 meningioma patients remaining alive had complete resections. There is a strong tendency for paediatric meningeal tumours to have a supratentorial origin and intraventricular location. The female preponderance found in adults is not evident in children. Incomplete surgical excision or focal neurological deficit at presentation was associated with poor outcome.

Adolescent↗
PubMed1996

Posterior skull surgery in craniosynostosis.

In 1984, two young infants with unusual "clover-leaf" patterns of skull deformity were treated by posterior skull-releasing surgery that dramatically improved their overall skull shape, to the extent that further operative intervention was not required. This focused our attention on the posterior skull and its role in craniosynostosis. In cases of multi-suture craniosynostosis and craniofacial syndromes severely raised intracranial pressure is frequent, demanding early surgery. One of the problems identified with such surgery undertaken before 6 months of age is recurrent craniosynostosis needing later re-operation. This occurred in 15 (5%) of 275 patients treated between 1978 and 1994. Since 1986, in the presence of significant raised intracranial pressure it has been our policy to do an initial posterior skull release or decompression. This takes the pressure of the growing brain away from the orbits, allowing us to defer fronto-orbital advancement until the age of 12 months or later. Three patients managed in this way completely avoided anterior surgery, while in another 9 patients re-operation for recurrent anterior deformity has not been required. The exception to this policy has been the presence of severe exorbitism posing a threat to vision. Under these circumstances early fronto-orbital advancement is mandatory, and an additional posterior skull release may be helpful later. Debate continues especially on the management of unilateral lambdoid synostosis. The recent increase in positional posterior plagiocephaly. possibly related to supine nursing of newborns, has emphasised the need to differentiate between a fixed deformity, which might require surgical correction, and positional moulding of the occiput, which improves spontaneously. This paper reports our experience with 22 patients treated by posterior skull surgery, either alone or as an additional procedure, which we believe has a definitive role in the management of craniosynostosis.

Adolescent↗
PubMed1996

Surgery for unilateral coronal synostosis (plagiocephaly): unilateral or bilateral correction?

Debate still exists concerning the extent of frontal reconstruction for the correction of plagiocephaly resulting from unilateral coronal synostosis. Between 1982 and 1994, 38 patients with unilateral coronal synostosis have been treated in our department. Initially, a unilateral frontal craniotomy with advancement of the ipsilateral supraorbital bar was used in 13 patients. An unsatisfactory postoperative appearance of the forehead led to modification of the technique using a bilateral frontal bone flap. This allowed simpler and improved forehead reconstruction. The method was used in 22 patients. Three patients with severe deformity had the complete supraorbital bar advanced in one piece and the forehead reconstructed with a bilateral frontal flap. The late results were analyzed using a clinical scoring system to grade residual deformity. The patients in the two main groups had similar characteristics. The mean age at first operation was 30.8 months for the first group and 20.1 months for the second group. Mean length of follow-up was 7.9 years for the first group and 4.6 years for the second group. No significant operative complications were observed. In two patients, one from each group, recurrent deformity developed, requiring further surgery. Analysis of the mean scores obtained at set intervals during the first 4 postoperative years showed that forehead correction with a bilateral frontal bone segment and unilateral supraorbital bar advancement provides better early cosmetic results in the first postoperative year. After that interval, the results of the two techniques are similar, with overall good final cosmetic appearances. The patients in the third group who had the complete supraorbital bar advancement with bilateral frontal bone remodeling had more pronounced deformity initially and had a less satisfactory late result. These findings confirm the clinical impression that bilateral frontal bone remodeling offers a better immediate surgical result from the cosmetic point of view compared with other techniques.

Adolescent↗
PubMed1996

Birmingham Craniofacial Score: a scoring system for craniofacial deformities.

A system was devised to score facial and head appearance in craniofacial patients in an attempt to quantify the severity of craniofacial deformities and measure the effect of corrective operations. It was deliberately kept simple to be "user friendly," and it must be regarded as incomplete. It has all the limitations of other scoring systems, but nevertheless it consistently reflects the results of operations, allowing quantitative comparisons and statistical analysis. It should be emphasized that deformity, not aesthetics, is measured. Fifteen features are scored. For every normal feature 1 point is awarded; for every abnormal feature, no point is scored. The range, therefore, extends from 0 to 15. In practice, there seems to be good correlation between the total score and the degree of deformity. A score of 13 or greater indicates that the appearance is cosmetically very good and the patient could be regarded as normal; a score ranging from 9 to 12 indicates a definite deformity; and a score of 8 or lower indicates the deformity is severe.

Cephalometry↗
PubMed1995

Treatment for children with brain tumours.

The overall survival for children with malignant brain tumours has not greatly improved in recent years, so that apparently innovative treatments may seem attractive, especially in cases with a poor prognosis. Problems associated with treating such children include balancing the need to provide optimum treatment for individual patients with the need to properly evaluate advances in treatment in clinical trials and determining who should be responsible for decisions about funding such treatments. Treatment abroad is rarely justified when judged on the basis of whether the treatment is available in Britain (or European Community) and whether there is accepted evidence for its clinical benefit. However, referral to specialist paediatric centres is essential. The range of daily experience in such centres allows an educated choice between established and new treatments. Close collaboration between these centres is essential for clinical trials.

Brain Neoplasms↗
PubMed1995

Cerebellar astrocytoma of childhood: long-term follow-up.

Cerebellar astrocytoma of childhood has always been regarded as a benign tumour. Certain issues still attract debate, in particular the role of radiotherapy as an adjuvant to surgery, management of the cyst wall in cystic lesions and treatment of recurrent tumours. To provide some answers to these questions, the experience in Birmingham (United Kingdom) between the years 1959 and 1991 was reviewed. Ninety-seven patients aged 0-14 years had been treated and the histological material was reassessed independently. Detailed statistical and clinical analysis revealed that the main factor of negative prognostic value was the presence of brain stem involvement. In cystic tumours the surgical excision of the cyst wall did not offer significant advantage on survival. Similarly, postoperative radiotherapy did not improve survival, and there is a suggestion that it may actually predispose to malignant transformation. The implications on management are discussed.

Adolescent↗
PubMed1995

Apert syndrome results from localized mutations of FGFR2 and is allelic with Crouzon syndrome.

Apert syndrome is a distinctive human malformation comprising craniosynostosis and severe syndactyly of the hands and feet. We have identified specific missense substitutions involving adjacent amino acids (Ser252Trp and Pro253Arg) in the linker between the second and third extracellular immunoglobulin (Ig) domains of fibroblast growth factor receptor 2 (FGFR2) in all 40 unrelated cases of Apert syndrome studied. Crouzon syndrome, characterized by craniosynostosis but normal limbs, was previously shown to result from allelic mutations of the third Ig domain of FGFR2. The contrasting effects of these mutations provide a genetic resource for dissecting the complex effects of signal transduction through FGFRs in cranial and limb morphogenesis.

Acrocephalosyndactylia↗
PubMed1995

Mutations in the third immunoglobulin domain of the fibroblast growth factor receptor-2 gene in Crouzon syndrome.

Craniosynostosis, which affects approximately 1 in 2000 children, is the result of the abnormal development and/or premature fusion of the cranial sutures. Studies of mutations in patients with craniosynostosis have shown that the family of fibroblast growth factor receptor genes are extremely important in the correct formation of the skull, and digits. Mutations in the third immunoglobulin domain of fibroblast growth factor receptor 2 (FGFR2), in part of the molecule corresponding to a tissue specific isoform (IIIc), can cause both Crouzon and Pfeiffer syndromes. Two specific mutations in the linking region between the second and third immunoglobulin domains of FGFR2 occur in Apert syndrome. We present here mutations associated with the Crouzon syndrome, also in the third immunoglobulin domain but in an upstream exon. This exon is expressed in both tissue isoforms. Five different mutations were detected in 11 unrelated individuals. A cysteine to phenylalanine change was found in six individuals. This cysteine forms half of the disulphide bridge maintaining the secondary structure of the immunoglobulin domain. The first deletion within an FGFR gene is reported. Together with mutations in exon IIIc these account for 25 mutations out of 40 Crouzon patients studied in our combined series (5).

Amino Acid Sequence↗
PubMed1995

Long-term complications of hydrocephalus.

Problems may still occur for patients treated for infantile hydrocephalus who graduate to become adults, including unsatisfactory follow-up. We have continued the supervision in an adult institution of 70 children originally treated in the Birmingham Children's Hospital between 1974 and 1978. In these patients, 33 (16.4%) of a total of 201 shunt revision procedures and 5 of the 8 subtemporal decompressions for slit ventricle syndrome were performed after the age of 16 years. Similarly, 7 shunt infections occurred in this age group. Two patients died from a blocked shunt. Other late complications included blindness (n = 1), endocarditis (n = 1), and renal and heart failure requiring consideration of organ transplantation (n = 1). Also 2 patients developed clinical features of arachnoiditis following earlier lumboperitoneal shunting. An overall good long-term outcome was observed. The majority of children graduated from a normal school (63%) or a school for physically handicapped children (21%). 67% of the patients are socially independent, but live at home with their parents. A further 16% have left their parents' home and live either on their own (10%) or with their partners (6%). It is clear that although a good social and educational outcome is expected, significant clinical problems do arise during adulthood for patients shunted in infancy, even after a long period of apparent stability. Regular follow-up by surgeons familiar with these problems is essential.

Adolescent↗
PubMed1994

Transcranial Doppler sonography in craniosynostosis.

In the management of craniosynostosis, there is a need for quantitative assessment of treatment methods and outcome. Radiology and pressure studies are well documented, but so far little attention has been given to cerebral blood flow changes and their possible relevance. This paper reports our initial experience using transcranial Doppler sonography to calculate the cerebrovascular resistance and cerebral blood velocities in the major basal vessels before and after surgery for craniosynostosis. Ten patients were studied using the Scimed 2-MHz probe through the temporal and frontal "windows" of the skull. Measurements were taken under standard physiological conditions before, during and after surgery. Preliminary results suggest that this non-invasive technique may be helpful in predicting and assessing the outcome following surgery for craniosynostosis.

Blood Flow Velocity↗
PubMed1994

Fronto-orbital re-operation in craniosynostosis.

The need for fronto-orbital re-advancement is reported from all cases of craniosynostosis operated on in the Birmingham and Oxford Craniofacial Units since 1979. Analysis of the 219 cases demonstrates a significantly higher re-operation rate in cases of syndromal craniofacial dysostosis or unilateral coronal synostosis initially operated on below the age of 6 months. Mild bicoronal, sagittal and metopic synostotic cases, however, did uniformly well with the timing of initial surgery having little influence on the re-operation rates.

Age Factors↗
PubMed1994

A distinct autosomal dominant craniosynostosis-brachydactyly syndrome.

We report a family with an autosomal dominantly inherited craniosynostosis. Five affected individuals have been identified with a variable clinical picture of premature coronal sutural synostosis accompanied by a mild midfacial hypoplasia and hypertelorism, downslanting external palpebral fissures, beaking of the nose and brachydactyly. This pedigree appears to represent a distinct craniosynostosis entity.

Adult↗
PubMed1993

Craniosynostosis.

Explore the source record for details and available documents.

Craniosynostoses↗
PubMed1990

Vascular anomalies of the scalp.

Paediatricians and surgeons of different disciplines are referred vascular anomalies of the scalp from time to time. These rare lesions may produce serious side-effects and the authors review the treatment of these abnormalities illustrated by five cases. Where possible, total excision is the treatment of choice.

Adolescent↗