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PubMedDate not supplied

Histologic comparison of a thermal dual-etched implant surface to machined, TPS, and HA surfaces: bone contact in vivo in rabbits.

PURPOSE: To evaluate the bone contact percentage around a proprietary high-temperature dual-etched (DE) implant surface (Osseotite) versus implants with machined, hydroxyapatite (HA), and titanium plasma-sprayed (TPS) surfaces. MATERIALS AND METHODS: Each implant type was placed in rabbit tibiae of the same animal and assessed at 1 to 8 weeks. Histologic sections were prepared and analyzed histomorphometrically. RESULTS: The DE implant surface achieved higher levels of bone contact percentage than the other surfaces. This enhanced contact level was apparent by 3 weeks and seen at all time intervals except 2 weeks, at which machined exceeded the DE mean. In evaluating which surface outscored the others in each individual rabbit, there was a statistically significant confidence for the DE surface (P < .001). The other 3 surfaces failed to show significance, although the numeric scores for the TPS surfaces were below random expectations and the machined scores were slightly above. There was no correlation between degree of roughness and bone contact percentage. DISCUSSION: Arbitrarily roughening the implant surface may not result in a large change in bone conductivity. The specific texture of the DE process yielded more contact, possibly as the result of better fibrin clot retention and growth factor enhancement. CONCLUSIONS: There was no advantage demonstrated in this model to an HA surface over titanium. The bone contact to the rough HA surface scored similarly to that for the TPS surface of similar roughness, and well below that for the DE titanium surface. The DE surface appeared to have an advantage in bone contact percentage, particularly in early healing in a rabbit tibia model.

Animals↗
PubMed1997

Stapedectomy vs stapedotomy. Do you really need a laser?

OBJECTIVE: To compare the effectiveness of different techniques of stapes surgery in improving the hearing of individuals with otosclerosis. METHODS AND DESIGN: Large and small fenestra techniques, as well as the instrument used to make the fenestra (drill or laser), were compared with regard to effectiveness and rate of side effects. The charts of 875 patients who underwent primary stapedectomies performed by members of the House Ear Clinic, Los Angeles, Calif, were reviewed. Patients who underwent stapedectomy for reasons other than otosclerosis and those with inadequate post-operative bone conduction threshold data were excluded. A group of 550 patients met the criteria. This group was broken into categories depending on the technique of stapedectomy and the instrument used to create the fenestra. The techniques were then compared using air-bone gap closure at different frequencies, pure tone average, and the rate of significant side effects. RESULTS: The study indicated that small fenestra stapedotomy and large fenestra techniques have similar rates of closure of the air-bone gap. Small fenestra stapedotomy has a slightly lower rate of postoperative sensorineural hearing loss, especially at higher frequencies. With regard to the small fenestra technique, there was no significant difference in either postoperative air-bone gap closure or postoperative sensorineural hearing loss, regardless of whether the fenestra was created by laser or microdrill. CONCLUSIONS: While we did find a statistically significant difference between the large and small fenestra techniques in postoperative sensorineural hearing loss at higher frequency, the difference is small and is probably not clinically significant. Therefore, we find that similar good results can be obtained by the experienced surgeon using either the large or small fenestra technique. Similarly, we found the laser and microdrill to be equally safe and effective in the creation of the fenestra.

Case-Control Studies↗
PubMed1994

Effects on sound localization of configuration and type of hearing impairment.

Localization ability of 87 bilaterally hearing-impaired listeners was tested in the horizontal and vertical planes, frontally and laterally. In those with sensorineural hearing loss, it was found that deficits in localization accuracy in different regions of auditory space could be related to different configurations of hearing loss. For example, there were associations between vertical plane discrimination and high-frequency sensitivity; and front-rear discrimination and mid-to-high-frequency sensitivity. These results agree with theoretical expectations, while the outcome overall contrasts with previous reports that localization performance is unrelated to audiometric configuration. A comparison of 13 listeners with conductive/mixed types of impairment with a sensorineural-loss group, matched for degree of loss, showed that a conductive component adds significantly to localization disturbance, particularly in the horizontal plane. The probable reason is a disturbance of low-frequency interaural time cues, and this occurs because a higher proportion of low-frequency sound is likely to be transmitted via bone conduction relative to air conduction. Correlations between hearing loss and localization are only moderate, suggesting that aspects of hearing impairment, in addition to simple attenuation, may also reduce auditory localization performance.

Adult↗
PubMed1999

Sex differences in patients with hearing impairments caused by otosclerosis.

The course of hearing in the non-operated ears was examined in 112 female patients and 63 male patients with bilateral otosclerosis who had operations in one ear only. All patients had a follow-up of at least 5 years. The mean annual impairment of the air conduction thresholds in the female patients (2.0-2.5 dB/year) did not differ significantly from that of the male patients (2.0-2.3 dB/ year). At the last follow-up examination, no difference was found between the sexes in the magnitude of the air-bone gaps. However, a sensorineural component developed in the women more frequently than in the men. Although at the last examination bone conduction thresholds of the female patients were significantly worse than those of the male patients, these were not matched by age.

Adult↗
PubMed1977

[A comparison of the results of incus interposition in the Wullstein type III and type IV tympanoplasty (author's transl)].

Incus interposition for reconstruction of the sound conduction mechanism in a deep tympanic cavity can be effectively utilized in both Wullstein Type III and IV tympanoplasties. In the Type III tympanoplasty, in which the incus is interposed between malleus or tympanic membrane and stapes, the average post-operative air-bone gap approximates 16 db, while incus placement on the stapes footplate results in an air-bone gap of 23.5 db. There is no difference in change of bone conduction when all operative mehtods are compared. Improved results in reconstruction of the second conduction mechanism are best obtained by conserving or reconstructing the tympanic membrane and posterior bony external canal wall through improved audio-physiologic dynamics.

Ear Canal↗
PubMed1979

Progressive sensorineural hearing loss and cochlear otosclerosis: a prospective study.

The association of otosclerosis with reduced bone conduction is well known but no experimental or valid clinical relationship has been established to confirm this relationship. The purpose of this presentation is to demonstrate a clinical relationship between otosclerosis and sensorineural hearing loss. Experimental proof will await the accumulation and study of temporal bones of those individuals who, in life, exhibited the clinical relationship to be developed in this dissertation.

Adolescent↗
PubMed2004

Evaluation of hearing thresholds in 3-month-old children with a cleft palate: the basis for a selective policy for ventilation tube insertion at time of palate repair.

Hearing thresholds in children with a cleft palate prior to cleft palate repair are not widely documented, and audiological criteria for short-term ventilation tube insertion do not exist. The aims of this prospective study are to estimate hearing thresholds in 40 children with a cleft palate by 3-month developmental age with auditory brainstem responses (ABRs) under natural sleep and to estimate a hearing threshold guideline for short-term ventilation tube insertion. Our results show a wide range of air conduction hearing thresholds using click ABRs (2-4 Hz), which ranged from 25 to 102 dBnHL in the left ear and from 25 to 80 dBnHL in the right ear with means of 53 and 49 and standard deviations of 17 and 13 respectively. The bone conduction thresholds ranged from 0 to 55 dBnHL with a mean of 26 and a standard deviation of 13. Eighty-three per cent of children had flat, type B, on high-frequency tympanograms, indicative of middle ear effusion. Thirty per cent of the infants had a cleft palate associated with a known syndrome. Currently, it is the authors' practice to use short-term ventilation tubes on a selective basis at the time of cleft palate repair when there is a conductive hearing loss of more than 55 dBnHL in the better ear as determined by ABR with type B high-frequency tympanograms. This threshold level takes into account electrophysiological and auditory pathway maturation discrepancies. With this as the guideline, between 28% and 35% of the children in this study would be eligible for surgery. This criterion still requires further validation.

Acoustic Impedance Tests↗
PubMed1994

Hearing results in surgery for primary petrous apex lesions.

Hearing preservation is a frequently mentioned phrase in the growing field of skull base surgery. Many authors have attempted to identify prognostic factors for successful hearing preservation, and many have suggested alternative procedures for preserving serviceable hearing. Few have mentioned hearing improvement with skull base surgical procedures. In this article we present the hearing results of 25 surgical procedures for primary petrous apex lesions. These include 13 cholesterol granulomas, 5 cholesteatomas, 4 mucoceles, and 3 eosinophilic granulomas. Surgical approaches included 14 transmastoid/infralabyrinthine, 6 transphenoid, 3 suboccipital, and 2 transmastoid/translabyrinthine. Hearing was maintained in 14 patients (56%), improved in 9 patients (36%), and worse in 1 patient with nonserviceable hearing before surgery (4%); 1 patient had profound hearing loss before surgery (4%). Results of this review should have significant implications on the choice of surgical approach for petrous apex lesions. Additionally, the standard method of determining salvageable hearing for most skull base procedures may not apply for this specific group of lesions. Implications for future treatment plans will be discussed in detail.

Adolescent↗
PubMed2005

Stapedectomy outcomes: titanium versus teflon wire prosthesis.

OBJECTIVE: To compare the effectiveness of two stapes prostheses in hearing improvement of patients undergoing stapes surgery for otosclerosis. STUDY DESIGN: Retrospective chart review. METHODS: Titanium and Teflon wire stapes prostheses were compared with regard to effectiveness in closing the air-bone gap. The charts of 461 stapedectomies performed by one surgeon from 1996 to 2001 were reviewed. Patients who underwent stapedectomy for reasons other than otosclerosis, revision cases, and those with inadequate preoperative or postoperative bone-conduction threshold data were excluded. Small fenestra technique using either laser or drill was used for all patients. Inclusion criteria were met by 218 patients. Patients were then grouped according to type of prosthesis used, and hearing outcomes were compared. Measured outcomes were four frequency air-bone gap closure, pure-tone threshold, and rate of sensorineural hearing loss (SNHL). RESULTS: The study group was comprised of 35 titanium and 183 Teflon wire prostheses. Closure of the air-bone gap to less than 10 dB was achieved in 86% of the patients with Teflon prosthesis compared with 71% of those with titanium prostheses. The groups were equivalent in regard to site of otosclerotic disease as well as technique, laser or drill, used to create the fenestra. Rate of SNHL was low for both groups and not significantly different. CONCLUSIONS: Both prostheses provided comparable results, although the Teflon platinum wire prosthesis was slightly superior. The smaller numbers in the titanium group may confound these results. The design of the titanium prosthesis provides a crimp that is circumferential around the incus, and that prosthesis was selected in cases with a narrow incus. The selection bias may also influence the results seen in this study.

Adolescent↗
PubMed2005

[Investigation for bone fixation effect of thin HA coated layer on Ti implants].

In 1995, the author reported the development of unique cementless total hip joints applying hydroxyapatite (HA) flame coating onto a porous titanium surface which is arc-sprayed with pure titanium material in argon gas at atmospheric pressure. The surface roughness of the porous layer was 360 microm Rmax, and the layer was more resistant to blast erosion than the conventional low pressure plasma sprayed porous layers. The thickness of the HA layer was between 20 and 40 microns considering the balance of bone conduction effect of HA and the risk of mechanical detachment of the layers from the porous titanium. Short-term animal tests showed excellent results. At that time a specific question was raised as to whether or not the coated HA layers would remain in the living bone for a long time. The results obtained from observation of retrieved specimens show that the thickness of the HA coating layer is sufficient for new bone formation after implantation, and HA would be absorbed in the body within a few years, after contributing to the new bone formation.

Absorption↗
PubMed2004

Vertigo, dizziness, and tinnitus after otobasal fractures.

Some 15% of temporal bone fractures are produced by blows to the occiput. The fracture line begins in the posterior fossa, at or near the foramen magnum, and crosses the petrous ridge through the internal auditory canal or the otic capsule. Thus, it is called a transverse fracture. In cases of transverse fractures of the temporal bone, due to automobile accidents or other causes of head injury, the labyrinth is involved more frequently than in longitudinal fractures. Severe vertigo with severe or total hearing loss is not uncommon in such injuries. In milder injuries, labyrinthine "concussion" may occur, with transitory auditory-vestibular symptoms. The force that causes the fracture is so great that it not only fractures the base of the skull but may cause a lesion of the brainstem, resulting in a combined peripheral and central lesion. We evaluated 61 patients (50 [81.97%] male, 11 [18.03%] female) with neurootological complaints of sequelae of otobasal fractures. Of these, 40.98% complained of tinnitus and 52.82% of hearing loss. Reviewing our experimental neurootometric investigations, we identified pathological processes on 75.41% of the butterfly calorigrams and 72.13% of the stepping craniocorpograms, as well as in 32.79% and 39.34% of subjects on right- and left-ear bone-conduction audiometry, respectively.

Adult↗
PubMed2000

[Osteoplasty of extensive jaw defects by protected bone regeneration using large pore resorbable implant].

This study was performed to demonstrate a protected bone regeneration method using macroporous resorbable sheets for the treatment of extended lower and upper jaw defects. By applying mechanical protection of bony defects with, e.g. membranes or titanium mesh, soft tissue prolapse as well as pressure on bone transplants which contributes to partial resorption can be avoided. The use of a pressure-resistant, resorbable, macroporous sheet combines the advantage of protected bone regeneration and complete resorption of the implanted sheet. The macroporous structure facilitates capillary ingrowth from the surrounding soft tissue. The sheet is made of 70:30 Poly(L-co-DL)-lactate with thermoplastic character and can be used as a container for autologous spongiosa or other osteoinductive and -conductive bone graft substitutes. In a pilot study, seven patients with lower jaw defects resulting from large cysts or tumor resections, some affecting the continuity of the mandible, were treated with this method. Following a protocol, X-rays were obtained to document the bony regeneration. The positive experience with this pilot study encouraged a multicenter project involving five university hospitals and 50 patients. The application of resorbable sheets in combination with transplantation of mersilized autologous spongiosa is currently being investigated. In future studies, fillings of sheets with osteoconductive and -inductive materials are planned.

Aged↗
PubMed2002

An intra-individual comparison of the previous conventional hearing aid with the bone-anchored hearing aid: The Nijmegen group questionnaire.

By spring 2000, a total of 351 patients were implanted in the Birmingham bone-anchored hearing aid (BAHA) programme. This group consisted of 242 adults and 109 children. The aim of this retrospective questionnaire study was to directly assess patient satisfaction with their current bone-anchored hearing aid in comparison with their previous conventional air and/or bone-conduction hearing aids. The Nijmegen group questionnaire was sent by post to 312 patients who used their BAHA for six months or longer. The questionnaire used was first described by Mylanus et al. (Nijmegen group) in 1998. The total response rate was 72 per cent (227 of 312 patients). The bone-anchored hearing aid was found to be significantly superior to prior conventional hearing aids in all respects.

Adolescent↗
PubMed2001

Fresh frozen bone in femoral impaction grafting: can developments in bone regeneration improve on this?

Major advances in the understanding of bone regeneration have led to revolutionary applications of bone conduction and induction. Revision hip surgery is on the increase with an active, ageing population demanding increased quality of life. The technically demanding instrumentation and materials necessary for revision prosthetic hip replacements have been rapidly incorporated into clinical practice. Unfortunately, advantage has not been taken of the basic and fundamental principles of bone induction and regeneration, available for many years now. In impaction grafting for revision hip replacements where fresh frozen bone is currently used as a standard, we argue and demonstrate from the literature why this technique is biologically inferior to the results which potentially can be gained by exploiting osteoinductive grafts such as demineralised bone matrix, hydroxyapetite, and inductive factors such as bone morphogenetic proteins.

Animals↗
PubMed1985

Congenital cholesteatoma of the petrous pyramid.

A 20-year follow-up was done on a patient with a large congenital cholesteatoma of the petrous apex. The patient was treated successfully with marsupialization through a radical mastoidectomy and sphenoid sinusotomy. Cranial computed tomography and magnetic resonance imaging demonstrated continued cholesteatoma growth. Bone-conduction thresholds remained normal despite replacement of the internal auditory canal by cholesteatoma matrix. The patient continues to have chronic otorrhea, but is otherwise asymptomatic.

Adolescent↗
PubMed1998

Temporal bone CT findings in the CHARGE association.

Ten out of 20 cases with the CHARGE association and two CHARGE-like cases underwent temporal bone CT scanning and/or MRI: they all showed bilateral aplasia of the semicircular canals and obliteration of the oval windows. Vestibular examination was performed in nine CHARGE cases and the two CHARGE-like cases, which disclosed vestibular areflexia in all of them. Of the 16 evaluable CHARGE cases, eight had bilateral mixed hearing impairment, while eight had sensorineural hearing impairment which was bilateral in six and unilateral in two cases. Temporal bone CT scanning is therefore indicated in suspected CHARGE cases, even if they show normal hearing or a relatively good bone conduction threshold in one or both ears.

Abnormalities, Multiple↗
PubMed1996

Basic fibroblast growth factor for stimulation of bone formation in osteoinductive or conductive implants.

Basic Fibroblast Growth Factor (bFGF) is one of the endogenous factors found in bone matrix. bFGF is a mitogen for many cell types, including osteoblasts and chondrocytes. It can stimulate angiogenesis and osteoblast gene expression. The purpose of this study was to investigate whether exogenous bFGF can stimulate the formation of bone in bone grafts and in a bone graft substitute. In a model using demineralized bone matrix implants for bone induction, a dose of 15 ng bFGF per implant increased the number of chondrocytes and the amount of bone, whereas 1900 ng greatly inhibited cartilage and bone formation. These results are consistent with previous studies with this model, showing that a lower dose of bFGF increased bone calcium content and a higher dose reduced it. Thus, exogenous bFGF can stimulate proliferation during early phases of bone induction. A new device, the bone conduction chamber, was developed for the application of bFGF to bone conductive materials. This model made it possible to demonstrate a difference between the conductive properties of bone grafts and porous hydroxyapatite. bFGF increased bone ingrowth into bone graft inside the chamber and showed a biphasic dose-response curve, so that 8-200 ng per implant (0.4-10 ng/mm3) increased bone ingrowth, but higher or lower doses had no effect. The same doses had the same effects in porous hydroxyapatite. In both bone grafts and porous hydroxyapatite, the highest dose still caused an increase in ingrowth of fibrous tissue. The effect on bone ingrowth was first detected after 6 weeks, regardless if administration of bFGF started at implantation or 2 weeks later, using an implanted minipump. Hyaluronate gel was effective as a slow-release carrier for bFGF. In conclusion, bFGF stimulates bone formation in bone implants, depending on dose and method for administration.

Animals↗
PubMed1999

[Analysis of surgical reconstructions of canal and middle ear via "direct entrance" approach in 53 ears with congenital aural atresia].

OBJECTIVE: To recognize the indication of surgical reconstruction via the "direct entrance" surgical approach (superoanterior surgical approach) for congenital atresia of the external acoustic canal and malformations of the middle ear. METHODS: A series of 53 ears operated on via the superoanterior surgical approach during 10 years from January 1988 to December 1997 was analyzed. RESULTS: The tympanic cavity was encountered without difficulty in 52 ears. Facial paralysis occurred postoperatively in one ear, which recovered after two months. The hearing improvement was observed in 45 ears (84.9%), of which 24 ears had hearing improvement greater than 30 dB and the air-bone conduction gap was within 15 dB (45.3%). A long-term (1-9 years) follow-up of 25 ears demonstrated that the hearing levels in 18 ears were kept unchanged. Postoperative stenosis of the canal occurred in one ear of a 2 years-old child. CONCLUSION: Based on the scanning images of the temporal bone by high-resolution computed tomography before the operation, the authors classified the bony structures of the paths of external acoustic canals into four types. Our results indicated that the selerotic and the diploetic paths of external acoustic cmeati could be indications for the "direct entrance" surgical approach, whereas the mixed type, either containing a little small cells or diploetic bone in sclerotic bone, might be suitable for this surgical approach also.

Adolescent↗