Factors affecting image acquisition during scanning laser polarimetry: authors' response.
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Artifacts↗
Biomedical subjects
R Maw
Publications and source records attributed to R Maw.
Introduction
Anogenital warts have become one of the most common sexually transmitted diseases reported in the Western World. The frustration of treatment for both patient and carer is well recognised. Current available methods rely principally on ablation of visible lesions, with hospital-based treatments often requiring multiple attendance by out-patients. Overall, the current failure rate, recurrence rate, and side-effects of these treatments are highly unsatisfactory. Imiquimod, recently launched in the US under the brand name Aldaratrade mark cream, represents the most interesting and innovative approach to therapy to become available in many years. Imiquimod is an immune response modifier, therefore this symposium report addresses the vital issues of the immune based response to human papilloma virus (HPV) infection, as well as the problems of persistence caused by HPV disease. The mechanisms by which imiquimod can induce an inflammatory and cell-mediated response are discussed. Also reviewed are the consequent imiquimod clinical results and the reasons why they show great cause for optimism in HPV treatment. As a home-based effective treatment with a low recurrence rate, imiquimod has already generated enthusiasm on an international scale. This symposium report presents the thoughts and experiences of medical specialists from various countries regarding the treatment of genital HPV infections and the place for imiquimod in clinical practice.
Journal Article↗
Factors affecting image acquisition during scanning laser polarimetry.
BACKGROUND AND OBJECTIVE: To illustrate artifacts that may be encountered during measurement of the peripapillary retinal nerve fiber layer (RNFL) using scanning laser polarimetry (SLP). PATIENTS AND METHODS: A total of 426 patients with a variety of ocular diagnoses underwent RNFL measurements using SLP from June 1996 to April 1997. Scanning was performed by two operators whose reproducibility of measurements had been previously validated. Images were selected to illustrate clinical features that adversely affected measurement of the thickness of the RNFL. RESULTS: Image acquisition was difficult in eyes with corneal grafts or edema, keratic precipitates, anterior uveitis, posterior subcapsular cataract, vitreous opacity, peripapillary atrophy, posterior staphyloma, and high axial myopia. These scans resulted in poor clinical correlation with visual field tests and optic nerve examination, poor reproducibility of images, and unreadable images. CONCLUSION: Anterior and posterior segment pathologies, particularly those localized to the cornea and lens, may produce spurious RNFL measurements and should be carefully considered prior to clinical decision making.
Aged↗
Are more passes better? Safety versus efficacy with the pulsed CO2 laser.
Whether greatly increasing the number of passes with the pulsed CO2 laser compromises safety or enhances effectiveness is unknown. Intuitively speaking, more passes should produce a greater depth of injury with better removal of wrinkles but greater likelihood of scarring. A chamois color has been said to signal laser penetration of the reticular dermis and has been recommended as an end point for safe treatment. Isolated case reports and anecdotal stories suggest that the potential for scarring from deep thermal injury remains significant. With the Coherent Ultrapulse laser at our usual therapeutic settings (300 mj, density of 4 with the Computerized Pattern Generator), the authors treated multiple test panels on in situ breast skin (one to 16 passes) and eyelid skin (one to eight passes) and then compared the panels in the excised skin histologically. The depth of injury did not increase after three passes, and no full-thickness injury was observed even in the thin eyelid skin. After treating severely wrinkled upper lips with up to 11 passes without scarring or other adverse effect, the authors treated a small series of patients with four passes on one side of their lips and 10 passes on the other side. No difference could be detected either at the time or after final healing. The authors believe that injury depth in using the pulsed CO2 laser is automatically limited by progressive dessication of the superficial dermis. The chamois color indicates dessication, not increasing depth. Although more than three or four passes will not produce injury under ordinary circumstances, they do not improve the final result.
Breast↗
Screening for obstructive sleep apnoea in children.
The prevalence of OSA increases with age depending on the techniques used and criteria accepted for definition of the condition. In children there may be a relationship of snoring to parental smoking. Night time problems may be worsened by use of anti-histamine sympathomimetic amine medication or cough suppressants. Disorders of sleep affect not only the child but also the parents and family. Progression to right heart failure is very rare and more likely in syndromic conditions. Whilst polysomnography will detect most of the changes of OSA, pulse oximetry may detect only two-thirds of adults with the condition and until now there has been no data for normal children examined at home.
Child↗
Manometric rhinometry.
A new method of measuring nasal volume is described. It works by extracting air from a closed cavity and measuring the resultant pressure change. To validate this method in the nose, 17 healthy volunteers were examined before and after application of xylometazoline. The apparent volume before decongestion was a mean of 204 ml. After decongestion the average volume was 228 ml. The difference is highly significant (P < 0.01). We conclude that manometric rhinometry is a valid method of investigating the nose and sinuses.
Adult↗
Physiological identification of the auditory nerve during surgery for acoustic neuroma.
We report the design and clinical use of an electrode which can locate the acoustic nerve fibres in the normal eighth nerve and also in eighth nerves deformed by acoustic neuromas. The improvement in facial nerve preservation during acoustic neuroma surgery is partly due to the use of a facial nerve stimulator to anatomically locate the fibres. Our new acoustic nerve detector has the capability of anatomical location of cochlear fibres which may help to improve hearing preservation in selected cases of acoustic neuroma. The device functions by detecting the compound action potential evoked by no frequency auditory simulation at 500 Hz. The 500 Hz compound action potential is detected with a bipolar probe and then amplified and filtered. This results in a 500 Hz tone when the probe contacts the auditory nerve. Detection is virtually instantaneous. The acoustic nerve detector (AND) is demonstrated in a normal eighth nerve complex and its use is then described in the total removal of an acoustic neuroma with a 1 cm extracanalicular extension in which useful hearing was saved post-operatively. The present prototype may not be sensitive enough to detect the very low signals that may result when cochlear fibres are widely distorted around a large tumour or in cases where slight contusion of the nerve occurs during dissection. In all other cases the real time anatomical information is extremely helpful in guiding acoustic nerve dissection and also in monitoring the effects of petrous bone drilling.
Amplifiers, Electronic↗
Manometric rhinometry: a new method of measuring nasal volume.
A new method of measuring the volume of the air space in the nose and sinuses is presented. We have called this method "manometric rhinometry." By closing off the nose anteriorly and posteriorly a closed space is created. A volume of air is then removed and the resultant pressure change is recorded. The original volume is calculated from the pressure change. Twenty adults have been investigated using this method. The volume recorded ranged from 78 to 198 ml (average: 138 ml). Test-retest analysis showed a correlation coefficient of 0.98. In addition, 24 children aged 4 to 12 years were examined. Their volumes were 43 to 198 ml. Test-retest analysis gave a correlation coefficient of 0.94. The significance of these findings is discussed.
Adult↗
Facial and acoustic nerve preservation during excision of extracanalicular acoustic neuromas using the suboccipital approach.
The results are presented from a consecutive operative series of 62 acoustic neuromas in 60 patients following the introduction of improved neurophysiological monitoring techniques. Twenty-two patients had usable preoperative hearing. Thirty tumours were less than 2.5 cm diameter and 32 greater in size. Operation was via a 3-4-cm diameter retromastoid craniectomy. The internal auditory meatus was opened by an ENT surgeon (RM) using a drill and the facial nerve identified by stimulation. The tumour was then centrally evacuated by a neurosurgeon (MT/HC) using an ultrasonic aspirator, and the thin exterior part of the tumour carefully dissected off the nerves in or around the capsule with constant stimulation and monitoring of facial EMG, BSAEP and electrocochleography. A new type of stimulation probe has been designed and coupled to a stimulator/integrator/tone burst generator (SB) so that continuous immediate direct feedback to the surgeon is possible. A variable amplitude discriminator rejects baseline EMG (> 50 microV) and a gating circuit prevents stimulus artefact (during monopolar stimulation) from causing interference. By these means the VII nerve could be identified even when translucent and undefinable as a nerve bundle. Anatomical preservation was possible in 98% of VII nerves. Full facial function was present in 20 cases immediately postoperatively. Full delayed recovery occurred in 23 cases giving an eventual total in House Grade I of 69%. Seven other cases recovered to House Grade II. There was therefore 81% satisfactory facial nerve function. This percentage is exactly the same for larger and for smaller tumours. Anatomical preservation of the VIII nerve was achieved in 24/62 (39%) of the whole series and 11/16 (69%) of those with a hearing loss of < 50 dB. Functional preservation of hearing described as usable by the patient (< 65 dB) was achieved in 7/22 cases (32%), 3/13 (23%) in tumours < 2.5 cm and 4/9 (44%) in those > 2.5 cm diameter. Hearing preservation of < 50 dB in patients with preoperative hearing threshold < 50 dB and tumours of < 2.5 cm was 3/11 (27%). Monitoring by BSAEP and ECochG was technically unsatisfactory because the responses were affected by drilling and stimulation. Acoustic nerve preservation should be attempted in all cases with measurable hearing, regardless of tumour size.
Ear Neoplasms↗
Spontaneous resolution of severe chronic glue ear in children and the effect of adenoidectomy, tonsillectomy, and insertion of ventilation tubes (grommets).
OBJECTIVE: To measure the time to spontaneous resolution of severe chronic otitis media with effusion (glue ear) in children and study the effects of adenoidectomy, adenotonsillectomy, and ventilation tubes (grommets). DESIGN: Randomised controlled study over 12 years. SETTING: Paediatric otorhinolaryngology clinics and in-patient unit. SUBJECTS: 228 children aged 2-9 years with pronounced hearing loss from glue ear and persistent bilateral middle ear effusions confirmed on three occasions over three months. INTERVENTIONS: Children were randomly allocated to adenotonsillectomy, adenoidectomy, or neither procedure. In all groups a Shepard type ventilation tube was inserted in one randomly chosen ear. Follow up was annually for five years and then less often for up to seven years four months. For analysis the two operated groups were combined. MAIN OUTCOME MEASURES: Otoscopic clearance of fluid, change in tympanogram, and improvement in mean audiometric hearing threshold. RESULTS: Survival analysis showed appreciable otoscopic and tympanometric resolution of fluid with ventilation tubes alone and adenoidectomy alone compared with no surgery. Further improvement was seen after combination of both treatments. Mean audiometric hearing thresholds improved with fluid resolution. Resolution was delayed in younger children and in those whose parents smoked, irrespective of treatment. Whereas a single insertion of a Shepard tube resolved the glue for a mean (SD) period of 9.5 (5.2) months, the effect of adenoidectomy was sustained throughout follow up. CONCLUSIONS: Treatment of glue ear considerably shortened the time to fluid resolution, combined adenoidectomy and tube insertion being better than either procedure alone. Resolution was longer in younger children and those whose parent(s) smoked, irrespective of treatment.
Adenoidectomy↗
Sexually transmitted disease in Northern Ireland.
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Adolescent↗
Ten year follow-up study of women presenting to a genitourinary medicine clinic with anogenital warts.
One hundred heterosexual women presenting at our clinic in 1979 with anogenital warts, were reviewed 10 years later. Median duration of warts following initial clinic attendance was 2 months (range 0-120 months). In 1979 cervical PAP smear results were available for 76 patients; cervical intraepithelial neoplasia (CIN) was seen in 15/76 (19.7%) women; 3 (4%) women had low grade CIN, 12 (15.7%) women had high grade CIN. Nineteen women had had treatment for CIN between 1979 and 1989, 7 laser ablation, 9 cone biopsy, 2 laser ablation and cone biopsy, and one woman laser ablation, cauterization and cone biopsy. At 10-year follow-up in 1989 4/100 women had anogenital warts, 12/100 women had cytological evidence of CIN (7 low grade, 5 high grade), and 37/100 women had CIN detected on colposcopic biopsy (31 low grade, 6 high grade). No women developed invasive cervical carcinoma during the study period. CIN lesions, detected in 1979, regressed without any treatment in 2 women. Colposcopic biopsy was 3.1 times more sensitive than single cervical PAP smear at detecting CIN (4.4 times as sensitive in detecting low grade CIN; 1.2 times as sensitive in detecting high grade CIN). In 1989 CIN was detected in 7/19 (36.8%) of women who had undergone cervical treatment between 1979 and 1989, and in 35/81 (43.2%) of women having no cervical treatment within this period (chi squared P greater than 0.5). These findings suggest that cervical laser ablative therapy and cone biopsy do not in the long term influence the natural history of cervical human papilloma virus-associated disease (CIN) in women with anogenital warts.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Anogenital warts in prepubertal children; sexual abuse or not?
Forty-two prepubertal children presenting with anogenital (AG) warts (15 boys and 27 girls) were prospectively followed up (mean 15.9 months, SD 12.24). Most (73.8%) of these children had perianal condylomatous-type warts and 11 (26.2%) had concurrent non-genital (NG) warts. None had any other AG infections or sexually transmitted disease (STD). Twelve (28.6%) children acquired their AG warts by vertical transmission from an infected maternal birth canal, 3 (7.1%) by autoinoculation from common hand warts and 2 children (4.8%) through sexual abuse. In the remaining 25 children (59.5%) mode of acquisition of AG warts was uncertain but not thought to be sexual. Human papilloma virus (HPV) DNA (types 6/11, 16/18 or 31,33,35-31+) was detected in 10/32 (31.3%) of AG warts biopsied from these children, types 6/11 in the majority of positive biopsies (9/10). Detection of HPV DNA (types 6/11, 16/18 or 31+) in a child's AG warts was significantly associated with either vertical or sexual transmission (P < 0.02). Thirty-one children had their warts treated with a combination of scissor excision and electrocautery under general anaesthesia. Warts recurred in 10 (31.4%) of these children all within 4 months following treatment. Spontaneous resolution of AG warts was seen in 9 (21.4%) children. Of 42 children with AG warts 10 (23.8%) had at least one adult family member with AG warts, 13 (36.9%) on adult family member with another AG infection or STD, and 23 (62.2%) had a mother with cervical intraepithelial neoplasia (CIN). Twenty (47.6%) of these children had a family member with NG warts.(ABSTRACT TRUNCATED AT 250 WORDS)
Anus Diseases↗