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PubMed2001

The nucleus double array cochlear implant: a new concept for the obliterated cochlea.

OBJECTIVE: To increase the number of intracochlear electrodes that may be inserted into a totally obliterated cochlea, a special implant has been developed in collaboration with Cochlear Limited. This implant features two separate electrode carriers containing 11 and 10 active electrodes, respectively, as well as a reference electrode located on the receiver-stimulator package. The potential stimulation modes available with this device therefore include monopolar and bipolar stimulation, and stimulation between both arrays. SURGICAL TECHNIQUE: A cochleostomy anterior to the round window provides access to the basal turn (both the scala tympani and the scala vestibuli), and new built connective tissue and bone can be removed until the anterior wall of the basal turn is approached. A second cochleostomy is performed at the second turn caudal of the cochleariform process and 2 mm anterior of the oval window after removal of the incus. New tissue should also be removed if necessary. The two electrode carriers are then placed into the scala tympani of the basal and the scala vestibuli of the second turn, respectively. The remaining surgical procedure is identical with that used for cochlear implantation in patients without obliterated cochleas. PATIENTS: In this clinical study, 10 patients aged 32 to 66 years with an obliterated cochlea each received a double array cochlear implant. All patients had total obliteration of the basal turn either on preoperative imaging or during surgery. Intraoperatively, the second turn was not obliterated in only 4 of 10 patients. Postoperatively, a standard audiologic test battery was used to determine auditory improvement over time. POSTOPERATIVE RESULTS: All patients achieved significantly improved speech understanding when the additional apical electrode array was used, compared with the use of each electrode array independently. No complications occurred. CONCLUSION: In patients with a totally obliterated cochlea, the number of intracochlear electrodes can be increased by use of the Nucleus double array implant. As a result, patients achieve significantly better auditory results.

Adult↗
PubMed2002

Binaural cochlear implants placed during the same operation.

OBJECTIVE: To evaluate the binaural listening advantages for speech in quiet and in noise and to localize sound when independently programmed binaural cochlear implants are used, and to determine whether ears with different hearing ability and duration of profound deafness perform differently with cochlear implants as well as to what extent preimplant psychophysical and physiologic assessment could be predictive of performance. STUDY DESIGN: Prospective study in which patients were prospectively selected to undergo bilateral implantation during a single surgical procedure at a tertiary referral center. All testing was performed with patients using their right, left, or both cochlear implants. Preimplant and intraoperative measures used electrical stimulation at the round window and stimulation through the cochlear implant. RESULTS: Bilateral implantation during the same operation did not cause any postoperative problems such as severe vertigo or ataxia. At 1 year, results of speech testing in quiet demonstrated a binaural advantage for 2 of 10 subjects. Speech-in-noise testing demonstrated that two implants were beneficial for two individuals. All subjects benefited from a head shadow effect when an ear with a better signal-to-noise ratio was available. The ability to localize sound was improved with binaural implants in all subjects. Preimplant psychophysical or physiologic measures were not predictive of eventual speech perception performance. CONCLUSION: Binaural cochlear implants can assist in the localization of sounds and have the potential in some individuals to improve speech understanding in quiet and in noise.

Adult↗
PubMed2002

Cochlear implantation for adolescents and adults with prelinguistic deafness.

OBJECTIVE: Previous studies have suggested that individuals with long-term prelinguistic deafness who receive cochlear implants show little improvement in speech recognition skills. The purpose of this study was to examine the auditory functioning of individuals with prelinguistic deafness who received cochlear implants after the age of 12. STUDY DESIGN AND SETTING: A retrospective study of open-set speech recognition was undertaken for 15 patients (adolescents and adults) with prelinguistic deafness who underwent implantation in the Ottawa Cochlear Implant Program. The results of open-set speech perception tests, both words and sentences, were reviewed to assess auditory functioning after implantation. Qualitative data using the Performance Inventory for Profound and Severe Loss questionnaire were also collected for the adults. RESULTS AND DISCUSSION: The results of this study indicate that individuals with long-term prelinguistic deafness can achieve significant open-set speech understanding with a cochlear implant, although there is a wide range of performance across patients. The results ranged from 0% to 74% for words and 0% to 98% for sentences.

Adolescent↗
PubMed2002

Preliminary ossiculoplasty results using the Kurz titanium prostheses.

OBJECTIVE: Limitations in biocompatibility and hearing improvement with ossicular chain reconstruction prostheses are addressed with new, lightweight titanium prostheses designed to maximize visualization of the capitulum and footplate regions. The effectiveness of these new prostheses is being tested in a prospective multicenter study. STUDY DESIGN: Prospective case series. SETTING: Multicenter (8 sites), primarily tertiary private practice or academic otologic clinics. PATIENTS: A convenience sample of 31 patients undergoing ossiculoplasty, with 16 partial ossicular chain reconstructions using the Bell prosthesis and 15 total reconstructions using the Aerial prosthesis. INTERVENTION: Ossiculoplasty using new Kurz titanium prostheses. Cartilage was interposed between the tympanic membrane and the prosthesis. MAIN OUTCOME MEASURES: Air-bone gap for pure tone average and 3,000 and 4,000 Hz, assessed preoperatively and 3 months, 6 months, and 12 months postoperatively; percent of patients obtaining an air-bone gap of </=20 dB; high-frequency average (1,000, 2,000, and 4,000 Hz) to evaluate sensorineural hearing loss; and extrusion rate. RESULTS: A postoperative air-bone gap of </=20 dB was obtained in 81% of Bell prosthesis patients and 67% of Aerial prosthesis patients at 3 months. The results were stable to improved for later time intervals. High-frequency gaps were similar to the pure tone average gap. To date, there have been no instances of extrusion, and all the surgeons found the prostheses easy to use and thought that the design characteristics facilitated accurate placement. CONCLUSIONS: Initial evaluation of the Kurz titanium prostheses produced low extrusion rates (none to date) with excellent hearing results, including good high-frequency conduction. Good visualization and accurate placement were easy to achieve. Further studies are needed to confirm long-term efficacy.

Audiometry, Pure-Tone↗
PubMed2005

Double posterior labyrinthotomy technique: results in three Med-El patients with common cavity.

HYPOTHESIS: This study reports on the use of the double posterior labyrinthotomy surgical technique and a custom-designed electrode to ensure better positioning of stimulating electrodes within the common cavity and thus demonstrate suitable outcomes in patients. BACKGROUND: Cochlear implantation has proven beneficial for numerous children with congenital malformations of the inner ear. Several studies show good auditory perception outcomes in children with common cavity. However, there have been risks involved with surgical techniques used in the actual implantation. These include possible aberrant facial nerve and the strong potential for a cerebrospinal fluid gusher. Improved surgical techniques and electrode design could allow for better electrode contact and avoid electrode placement in the internal auditory meatus. METHOD: The double posterior labyrinthotomy technique was carried out in three cases using a custom made MED-EL COMBI 40+ electrode. RESULTS: Surgery was carried out with no complications and is no more technically demanding than other standard surgical approaches. The speech processor program remains stable over time, and auditory perception results are similar to those obtained from children with no cochlear abnormalities. CONCLUSION: These results demonstrate the success of the double posterior labyrinthotomy approach with modified cochlear implant, and this could be recommended as the procedure of choice in children presenting to an implant team with a common cavity.

Child, Preschool↗
PubMed2004

Optimizing dynamic range in children using the nucleus cochlear implant.

OBJECTIVE: The aim of this study was to investigate the benefits of the preprocessing scheme "Adaptive Dynamic Range Optimization" (ADRO) in children using Nucleus cochlear implants. Previous research with adults indicates improved speech perception in quiet and improved sound quality in everyday listening environments with the ADRO scheme. DESIGN: Children were given 4 wk of take-home experience with ADRO, with a minimum of 2 wk in which ADRO was "locked-in." After 1 wk of ADRO use and again after 4 wk of ADRO use, Bench-Kowal-Bamford (BKB) sentence perception in quiet at a low input level of 50 dB SPL (unweighted root mean square) and sentence perception in noise were compared with the child's everyday (Standard) program and the ADRO program. Children also rated the loudness of a variety of environmental sounds and indicated which program provided the best hearing in a variety of everyday listening situations. RESULTS: On average, BKB sentence perception in quiet at 50 dB SPL was significantly better with the ADRO program compared with the Standard program. The group mean improvement was 8.60%. Similarly, group mean scores for BKB sentences presented at 65 dB SPL in multitalker babble were significantly higher with the ADRO program (an improvement of 6.87%). The ADRO program was the preferred program in 46% of the listening situations, whereas the Standard program was preferred in 26% of situations. Everyday sounds were not unacceptably loud with ADRO. CONCLUSIONS: There was an ADRO benefit for this group of children in quiet and in noise. These findings suggest that young children would benefit from the ADRO programming option being locked in along with other processor settings in the SPrint processor once their MAP levels have stabilized. Some older children and teenagers may choose to use ADRO selectively for specific listening situations.

Acoustic Stimulation↗
PubMed2006

The influence of RECD transducer when deriving real-ear sound pressure level.

OBJECTIVE: The main aim of the present study was to compare the derived and directly measured real-ear hearing instrument performance for a range of commonly used hearing instruments. A secondary aim was to compare the real-ear to coupler difference (RECD) measured using the ER-3A insert earphone and a selection of hearing instruments. DESIGN: The real-ear SPL was measured for four models of hearing instrument in 20 adult participants using an Audioscan RM500 real-ear system. This was compared with the derived real-ear SPL obtained by adding the RECD (measured using the ER-3A insert earphone) to the 2-cc coupler response of each hearing instrument. Measurements were made at 1/12 octave intervals from 0.2 to 6 kHz, using both the HA1 and HA2 2-cc coupler. In addition, the RECD was measured using four models of hearing instrument for comparison with the ER-3A insert earphone values. RESULTS: The procedures were very reliable with mean differences on retest of less than 1 dB. Repeated-measures analysis of variance revealed statistically significant differences between the measured and derived real-ear SPL (p < 0.001) for several models of hearing instrument. The derived responses using the HA1 coupler yielded good accuracy, whereas the HA2 yielded less accuracy. For three models of hearing instrument, the maximum difference was between 5 and 10 dB when using the HA2 coupler. The mean RECD measured with the ER-3A insert earphone and HA2 coupler was not always equivalent to the RECD measured with the hearing instruments. CONCLUSIONS: The accuracy of the derived real-ear response obtained using an RECD, measured with an ER-3A insert earphone, is very good when an HA1 is used for the coupler component of the RECD. The accuracy diminishes somewhat with the HA2 coupler, especially for undamped hearing instruments. The accuracy of the derived real-ear response is very good when the RECD is measured using the hearing instrument and the HA1 or the HA2 coupler.

Adult↗
PubMed2004

The current role of structural grafts and cages in revision arthroplasty of the hip.

Treating large segmental acetabular defects that comprise more than 50% of the acetabulum is one of the most difficult challenges in revision arthroplasty of the hip. One of the surgical options is a structural acetabular allograft. Unless these allografts are protected by a cage that extends from ilium to ischium, there is an unacceptable incidence of graft failure. The cage allows reconstruction at the correct anatomic level. It provides a scaffold for bone grafting (structural and morsellized). The use of cement to stabilize the cup allows the surgeon to adjust the cup position independent of the cage. The current generation of cages does not provide biologic fixation and with time may loosen or fracture. Recent experience with a combination of a trabecular metal shell protected by a cage may offer a more favorable environment for bone grafting with permanent biologic fixation of the cup cage construct.

Acetabulum↗
PubMed2005

Computer-assisted navigation increases precision of component placement in total knee arthroplasty.

UNLABELLED: In our clinical study, 200 total knee arthroplasties were evaluated to compare the use of the OrthoPilot system with conventional mechanical instrumentation. Long-term outcome of total knee replacement depends mainly on the accuracy of implant positioning and restoration of the mechanical leg axis. Our experience was that navigation could achieve a greater degree of accuracy concerning the aforementioned aspects. Among 513 primary-inserted total knee replacements, 100 navigated knees were compared with 100 conventionally implanted knees after matching the two groups of patients by gender, body mass index, age, preoperative deformities, radiographic findings, and operating time. Three weeks after surgery, the radiographic results were significantly better in the computer-assisted group compared with the results in the conventional group when we assessed component positioning in four axes. Only the sagittal tibial component angle was not significantly different. Total knee arthroplasty using the OrthoPilot system led to increased precision of tibial and femoral component positioning in comparison with hand-guided replacement surgery. An additional 10 minutes of operating time was acceptable. Navigation-specific complications were not seen, and the number of outliers decreased. Because computer navigation in orthopaedics is a new technology, data regarding long-term outcomes are not available. LEVEL OF EVIDENCE: Diagnostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2005

Computer navigation versus standard instrumentation for TKA: a single-surgeon experience.

UNLABELLED: Component alignment errors in total knee arthroplasty greater than 3 degrees can be associated with poorer outcomes. This retrospective study seeks to determine if computer navigation can improve accuracy of component alignment in comparable patient populations. The efficiency and safety of the navigated technique is also evaluated. Fifty total knee arthroplasties done using an imageless navigation system and 50 cases using standard instrumentation were compared. The same surgeon used a single system (Zimmer-Natural Knee) in all cases. Long-standing radiographs collected at 6-week followup were measured for component orientation. When the navigation system was used 98% (49 of 50 cases) of all femoral components and 100% (50 of 50 cases) of all tibial components were placed within +/- 3 degrees of the radiographic goal position. There was a decrease in the standard instrumentation group to 90% (45 of 50 cases) and 92% (46 of 50 cases) within +/- 3 degrees , respectively. There was a difference in the standard deviations observed for the navigated cases and the conventional cases when femoral and tibial component position was considered. Average tourniquet time was 68 minutes in the navigated group and 57 minutes in the conventional group. There were no technique specific complications associated with the navigation system. This system affords the surgeon the potential to reduce outliers with regard to component position without an increase in complications. Tourniquet times were increased with the use of the computer. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (retrospective comparative study). See the Guidelines for authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2005

Cancellous bone strains indicate efficacy of stem augmentation in constrained condylar knees.

Modular augmented stems of a constrained condylar knee implant are intended to improve tibial fixation under increased varus/valgus loads, but conflicting studies have not yet indicated the factors determining stem usage and performance. To address this, we combined a paired-tibiae, cadaveric experiment of unstemmed and stemmed tibial components with specimen-specific computational models. We hypothesized that the stem would improve implant stability by decreasing implant motion and compressive strains in the proximal cancellous bone due to load transfer by the stem. The models also would indicate the important factors governing stem performance. Large variations of the displacements arose because of loading and biologic variability indicating the inconclusive effects of a stem. Despite these variations, the models showed that a stem augment consistently decreased the strains (30%-50%) in the bone beneath the tray. In tibiae of sufficient stiffness, the supporting cancellous bone did not approach yield, suggesting that a stem augment may not always be necessary. On the other hand, tibial specimens with reduced bone quality and lower stiffness benefited from a stem augment that transferred load to the distal cortical bone. Therefore, patient selection and proper sizing of the implant were identified as important factors in the analyses.

Aged↗
PubMed2006

Large diameter femoral heads on highly cross-linked polyethylene: minimum 3-year results.

Contemporary highly cross-linked polyethylenes have become the most widely used alternative bearing surfaces in total hip replacement and may be paired with large diameter femoral heads (> 32 mm) in patients considered to be at high risk for dislocation. We report on a prospective series of 42 patients (45 hips) who had total hip replacement using large diameter cobalt-chrome femoral heads articulating with a highly cross linked polyethylene after a minimum of 3 years followup (mean 3.3 years). At final followup, the final patient cohort showed excellent clinical results with no radiographic failures or episodes of loosening. There was no evidence of pelvic or femoral osteolysis. One patient sustained a dislocation due to a grossly malpositioned acetabular component necessitating early isolated acetabular revision. The average yearly steady state wear rate was -0.06 +/- 0.41 mm/year. The results of our short-term prospective series indicated total hip replacement with large femoral heads articulating with a highly cross linked polyethylene showed excellent wear characteristics and clinical results and could be considered in patients at increased risk for dislocation.

Aged↗
PubMed2006

A constrained device with increased range of motion prevents early dislocation.

Constrained components can treat or prevent instability after total hip arthroplasty. Some previous designs have shown a high rate of early dislocation. These early dislocations appear to be secondary to component impingement and levering out of the femoral head. We report the early rate of dislocation in 81 consecutive patients undergoing constrained total hip arthroplasty using a novel constrained device that allows substantially more range of motion and a higher lever out strength. One hip redislocated at 6 months followup, for a success rate of 98.8%. The success rate was 93% for patients for whom a constrained device was placed during revision for recurrent instability. This device allows a higher range of motion before prosthetic impingement and maintains a higher levering out strength when impingement occurs. These changes should provide long lasting hip stability in these difficult cases.

Adult↗
PubMed2006

Influence of total hip design on dislocation: a computer model and clinical analysis.

Dislocation following hip arthroplasty remains problematic. While the etiology of dislocation may be multifactorial, implant system design may play a role. Using a computer aided design program, virtual range of motion of several commonly implanted designs was performed with prosthetic interference representing impingement used as an endpoint. Implants with small diameter head size (22 mm) and a larger trunion geometry (type II taper) demonstrated impingement in flexion at less than 90 degrees , suggesting an increased risk for dislocation. To investigate this clinically, we performed a review of a consecutive series of 254 primary hip arthroplasties performed by a single surgeon using an implant with a type II taper (Biomet, Warsaw, IN). At a minimum 2 year followup, 12 patients with 12 hips (4.8%) had at least one episode of dislocation. Stratified by head size, the dislocation rates were 3.6% for 28 mm, 4.8% for 26 mm, and 18.8% for 22 mm bearings. These findings support the notion that computer aided design modeling of implant systems is useful in evaluating range of motion and this technique could be employed during the design of any new implant system.

Arthroplasty, Replacement, Hip↗
PubMed2006

A new tool for measuring cup orientation in total hip arthroplasties from plain radiographs.

Orientation of the hip cup is important in total hip arthroplasties. Orientation includes abduction (inclination) and anteversion. Anteversion can be considered as true (anatomic) and planar (radiographic) anteversion. Some measurement methods either are too complicated or are less precise. We developed a new protractor to measure cup orientation using postoperative anteroposterior radiographs centered at the hip. The new protractor measures true and planar anteversion and abduction easily and precisely. We verified its accuracy using a software simulator and simulated 45 radio- graphs of total hip arthroplasties with 15 different anteversions ranging from 15 degrees -29 degrees and 45 actual radiographs of total hip arthroplasties. We then measured the planar ante- version with our method and the method of Lewinnek et al. Maximal errors were 3 degrees and 2.61 degrees , respectively, and mean errors were 0.96 degrees and 1.2 degrees , respectively. The standard deviations were 0.74 degrees with our method and 0.57 degrees with the method of Lewinnek et al. For the real radiographs, the mean of absolute difference between the two methods was 1.34 degrees , and the standard deviation was 1.13 degrees . We found no difference between the two methods and no difference in our findings compared with those of Pradhan.

Acetabulum↗