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Biomedical subjects

Adrian L James

Publications and source records attributed to Adrian L James.

9 recordsLinked to original sources
PubMed2006

Inner ear dysplasia is common in children with Down syndrome (trisomy 21).

OBJECTIVES/HYPOTHESIS: Middle and external ear anomalies are well recognized in Down syndrome (DS, trisomy 21). Inner ear anomalies are much less frequently described. This study reviews inner ear morphology on imaging to determine the prevalence of cochlear and vestibular anomalies in children with DS. STUDY DESIGN: The authors conducted a retrospective review of imaging features of (DS) inner ear structures. METHODS: Fifty-nine sequential patients with DS with imaging of the inner ear were identified by a radiology report text search program. Quantitative biometric assessment of the inner ear was performed on patients with high-resolution computed tomography or magnetic resonance images of the petrous bone. Petrous imaging was performed for evaluation of inflammatory disease or hearing loss. Spinal imaging, which included petrous views, was performed in most cases to exclude C1 to 2 dislocation, a potential complication of DS. Measurements were compared with normative data. RESULTS: Inner ear dysplasia is much more common in DS than previously reported. Inner ear structures are universally hypoplastic. Vestibular malformations are particularly common and a small bony island of the lateral semicircular canal (<3 mm in diameter) appears highly typical. Additional findings in some patients were persistent lateral semicircular anlage with fusion of the lateral semicircular canal and vestibule into a single cavity, vestibular aqueduct and endolymphatic sac fossa enlargement, cochlear nerve canal hypoplasia, and stenosis or duplication of the internal auditory canal. Stenosis of the external meatus, poor mastoid pneumatization, middle ear and mastoid opacification, and cholesteatoma were common, as expected.

Adolescent↗
PubMed2005

Dynamics of real time DPOAE contralateral suppression in chinchillas and humans.

The dynamics of contralateral acoustic suppression were studied using real time (millisecond resolution) distortion product otoacoustic emissions (DPOAEs) in chinchillas and humans. Latency of DPOAE suppression onset is 26 ms in chinchillas and 45 ms in humans. After onset, suppression builds over time before tending to plateau, reflecting a temporal integration process with a time constant of 100 ms (chinchillas). In chinchillas, suppression persists for 40 ms even when elicited by stimuli as short as 5 ms. With stimuli >40 ms, offset and onset latencies are similar and duration of suppression equals that of the contralateral stimulus. A comparison of DPOAE suppression onset latency with neural latency data from the pathways involved suggests the following timing scheme: stimulus onset to activity in (ventral) cochlear nucleus, 4ms (15% of delay); transfer to olivocochlear efferents, 9 ms (35%); efferent conduction to presynaptic OHC site, 4ms (15%); synaptic and mechanical events at OHCs, 9 ms (35% of delay).

Adolescent↗
PubMed2004

Device fixation and small incision access for pediatric cochlear implants.

OBJECTIVE: Small incision cochlear implant surgery has been advocated to improve cosmesis and reduce post-operative morbidity. However, with standard small incision techniques, it is not possible to securely fix the device in place. This risks displacement of the device, particularly in active children. This paper describes the development of a technique which combines secure ligature tie-down of the device with a small incision. METHODS: A 25 mm skin incision is positioned close to the hair line behind the pinna. Specially modified instruments are used to drill a well for the receiver-stimulator pedestal down to dura. In younger children, ligature tie-down holes are drilled through the calvarium. Alternative methods for older children are described. Outcome data are reviewed. RESULTS: One hundred children have been implanted with the small incision technique. No complications have occurred related to the current technique (maximum follow up 22 months). In five cases, during early development of the technique, the receiver-stimulator device was only secured by a tight periosteal pocket. In one of these cases, the device became dislodged from its well. CONCLUSIONS: Secure fixation of the receiver-stimulator unit of a cochlear implant is particularly important in children because of the risk of displacement with trauma. The conventional means of securing the device with a ligature has been combined with modified small incision techniques to meet this requirement successfully.

Adolescent↗
PubMed2004

Cochlear implant surgery at 12 months of age or younger.

OBJECTIVES: Early presentation of congenitally deaf children for cochlear implantation is leading to surgery in younger candidates. The safety of cochlear implantation in children aged 12 months and younger is reviewed with radiologic assessment of mastoid bone anatomy and surgical outcome data. STUDY DESIGN: Analysis of case records and temporal bone computed tomography (CT) scans with description of surgical technique in infants. METHODS: Chart analysis of children aged 12 months or younger at cochlear implantation. Mastoid bone anatomy was compared with older children (mean age 2 years) using CT scans. RESULTS: Twenty-five infants received implants at 7 to 12 months of age because of meningitis (n = 4) or early detection of deafness (n = 21). Mastoid marrow content on CT scan was significantly greater in this age group (P < .001 Mann-Whitney rank sum test), but pneumatization was always adequate for safe identification of surgical landmarks. The smaller size of the mastoid bone was not restrictive. An extended postauricular approach was used in the first 11 cases and a 2.5 cm hair-line incision in the remainder. Ligature tie-down of the device was completed in all cases. No complications occurred. All are full-time implant users, except one with other neurologic sequelae of preoperative meningitis. CONCLUSIONS: In our experience, cochlear implant surgery is safe in children aged 7 to 12 months with appropriate anesthetic and postoperative support. The small incision technique is particularly suited to this age group. Ligature fixation of the device is considered advisable because of the increased risk of displacement from frequent falls when learning to walk.

Age Factors↗
PubMed2004

Skin breakdown over cochlear implants: prevention of a magnet site complication.

OBJECTIVE: To determine the prevalence of inflammation of the skin around the magnet of cochlear implants. METHOD: A postal survey of 232 children implanted at The Hospital for Sick Children, Toronto, detailing the timing and severity of skin inflammation near the magnet. RESULTS: Sixty-three children (27%) had at least one episode of skin erythema at the magnet site. In most cases, this resolved after reducing magnet field strength. Nine children stopped wearing the device briefly, and five were treated with antibiotics. Skin ulceration occurred in two cases. No surgical treatment was required. Reactions tended to occur in younger children (2.8 vs 4.3 years; p = .002, Mann-Whitney rank sum test). CONCLUSIONS: Skin inflammation commonly occurs in children between magnets of the transmitter and receiver coils of a cochlear implant. If inflammation fails to resolve after loosening the magnet, use of the implant should be discontinued temporarily. Antibiotics should be prescribed for cellulitis to prevent an implant-threatening infection.

Adolescent↗
PubMed2004

Effects of middle ear application of Cipro HC Otic Suspension in an animal model.

The objective of this study was to examine whether ciprofloxacin-containing otic drops (Cipro HC Otic Suspension; 0.2% ciprofloxacin, 0.1% hydrocortisone; Alcon, Ontario, Canada) are cochleotoxic in the chinchilla animal model. Five chinchillas in total underwent these studies. Pretreatment distortion-product otoacoustic emissions (DPOAEs) were measured in each ear, followed by a random injection of Cipro to one ear and normal saline to the other. Injections consisted of 0.2 mL into the middle ear cavity (bulla) for 5 consecutive days. Post-treatment DPOAEs and auditory brainstem responses were measured at 1 month, and cochlear hair cell integrity was assessed by scanning electron microscopy (SEM). All animals had normal pretreatment DPOAEs. One month after Cipro instillation, DPOAE levels decreased in three of the animals. No significant change was seen in the ears treated with saline. On SEM examination, the integrity of the stereocilia of the inner and outer hair cells demonstrated no histologic evidence of significant cochlear damage. The finding of reduced DPOAEs suggests a mild local middle ear inflammation caused by the ciprofloxacin or some other component or property of Cipro.

Animals↗
PubMed2003

Investigation of cardiac function in children with suspected obstructive sleep apnea.

OBJECTIVE: To assess the prevalence of cardiac failure in a group of children with suspected obstructive sleep apnea (OSA) and to assess the need for preoperative electrocardiograms (ECGs) and chest radiographs (CXRs) in children with OSA. DESIGN: Case record review of 271 children having (adeno)tonsillectomy for symptoms of OSA. METHOD: Preoperative ECGs and CXRs were assessed for signs of right atrial or ventricular hypertrophy or failure. Case records were assessed for evidence of cardiac failure during anaesthesia. RESULTS: One child with congenital heart disease had signs of cardiac failure preoperatively. No other cases of atrial or ventricular hypertrophy or failure were found. CONCLUSIONS: Cardiac failure appears to be uncommon in children with symptoms of OSA. Preoperative ECG and CXR are essential in only selected cases.

Adolescent↗
PubMed2002

Establishment of a bone-anchored auricular prosthesis (BAAP) program.

OBJECTIVE: Bone-anchored auricular prostheses (BAAPs) are indicated for treatment of congenital or acquired microtia in children. This paper reports on our experience in establishing a BAAP program, including treatment algorithms, protocols and a discussion of the methodology, complications and patient satisfaction. METHODS: Eleven consecutive children using BAAPs were reviewed. Outcome measures include patient selection criteria, long-term stability of the BAAP, skin reactions around the site, and patient satisfaction. RESULTS: A patient selection program was developed and implemented, followed by a management protocol for surgery and follow-up. All children (100%) achieved osseointegration, with only one site revision necessary. A variable degree of skin irritation was noted in just over one third (39%) of cases. All children were satisfied with their prosthesis. CONCLUSIONS: The use of BAAPs in a pediatric population is a safe and viable method to correct disfiguring microtia. The final result is generally very acceptable to the child.

Adolescent↗