Comparing Heterotopic Ossification in Two Cervical Disc Prostheses.

STUDY DESIGN: Retrospective analysis using data from randomized clinical trials. OBJECTIVE: To compare the occurrence of heterotopic ossification (HO) between two cervical disc prostheses. Clinical outcome and range of motion (ROM) were also evaluated. SUMMARY OF BACKGROUND DATA: Cervical arthroplasty was reported to be able to maintain the segmental ROM. However, controversy exists since the difference of the occurrence of HO concerning cervical prosthesis is still huge. METHODS: Patients who underwent anterior cervical discectomy with arthroplasty for a cervical radiculopathy due to a herniated disc from the The Netherlands Cervical Kinematics (NECK) trial (activC; metal endplates with a polyethylene inlay and a keel for primary stability) and the PROCON trial (Bryan; metal-on-polymer with titanium coated endplates without a keel) were analyzed for HO at 12 and 24 months postoperatively. HO was scored according to the McAfee-Mehren classification. Segmental ROM was defined by a custom developed image analysis tool, and global cervical ROM was measured by Cobb's angle. Clinical outcome was evaluated by means of the neck disability index (NDI) as well as physical-component summary (PCS) and mental-component summary (MCS). RESULTS: At 2-year follow-up, the occurrence of HO was 68% in patients treated with the activC prosthesis (severe HO 55%), which was comparable with 85% (P = 0.12) in patients with the Bryan disc (severe HO 44%; P = 0.43). The HO progression was similar between groups. Clinically, the patients had comparable NDI, PCS, and MCS at 2-year follow-up, and comparable improvement of clinical outcomes. The global ROM in the Bryan group (56.4 ±â€Š10.8°) was significantly higher than in the activC group (49.5 ±â€Š14.0, P = 0.044) at 2-year follow-up. CONCLUSION: In comparison of two cervical disc prostheses the development of HO is independent on their architecture. Although global ROM was higher in the Bryan prosthesis group, this difference was not deemed clinically important, particularly because the clinical condition of patients with and without severe HO was comparable. LEVEL OF EVIDENCE: 2.

Effects of Surface Topography and Chemistry on Polyether-Ether-Ketone (PEEK) and Titanium Osseointegration.

STUDY DESIGN: An in vivo study examining the functional osseointegration of smooth, rough, and porous surface topographies presenting polyether-ether-ketone (PEEK) or titanium surface chemistry. OBJECTIVE: To investigate the effects of surface topography and surface chemistry on implant osseointegration. SUMMARY OF BACKGROUND DATA: Interbody fusion devices have been used for decades to facilitate fusion across the disc space, yet debate continues over their optimal surface topography and chemistry. Though both factors influence osseointegration, the relative effects of each are not fully understood. METHODS: Smooth, rough, and porous implants presenting either a PEEK or titanium surface chemistry were implanted into the proximal tibial metaphyses of 36 skeletally mature male Sprague Dawley rats. At 8 weeks, animals were euthanized and bone-implant interfaces were subjected to micro-computed tomography analysis (n = 12), histology (n = 4), and biomechanical pullout testing (n = 8) to assess functional osseointegration and implant fixation. RESULTS: Micro-computed tomography analysis demonstrated that bone ingrowth was 38.9 ±â€Š2.8% for porous PEEK and 30.7 ±â€Š3.3% for porous titanium (P = 0.07). No differences in fixation strength were detected between porous PEEK and porous titanium despite titanium surfaces exhibiting an overall increase in bone-implant contact compared with PEEK (P < 0.01). Porous surfaces exhibited increased fixation strength compared with smooth and rough surfaces regardless of surface chemistry (P < 0.05). Across all groups both surface topography and chemistry had a significant overall effect on fixation strength (P < 0.05), but topography accounted for 65.3% of the total variance (ω = 0.65), whereas surface chemistry accounted for 5.9% (ω = 0.06). CONCLUSIONS: The effect of surface topography (specifically porosity) dominated the effect of surface chemistry in this study and could lead to further improvements in orthopedic device design. The poor osseointegration of existing smooth PEEK implants may be linked more to their smooth surface topography rather than their material composition. LEVEL OF EVIDENCE: N/A.

Primeras experiencias con el dispositivo osteointegrado Ponto(TM) SuperPower / First experiences with the Ponto(TM) SuperPower osseointegrated device

Los dispositivos auditivos osteointegrados (DAO) Power y SuperPower presentan indicaciones para umbrales en vía ósea de 55 y 65dB, respectivamente. Realizamos un estudio observacional prospectivo de una serie de 6 casos con hipoacusia mixta en los que se realizó implantación del DAO Ponto(TM) SuperPower. Se realizaron previo a la implantación y 6 meses tras la adaptación valoraciones tonales y verbales sin y con ruido de fondo (HINTS). Todos los participantes mostraron mejoría en los resultados tonales y verbales, variando según el grado de hipoacusia contralateral. Cabe destacar los resultados verbales con ruido de fondo donde la mayoría de los pacientes obtuvieron una relación señal ruido entre 2 y 4 dB. Los resultados en los cuestionarios APHAB y GBI mostraron una reducción de la percepción del problema y una mejoría en la calidad de vida, respectivamente. Los resultados presentados reflejan la posibilidad de tratamiento de hipoacusias mixtas con el dispositivo DAO Ponto(TM) SuperPower

Osseointegrated hearing devices Power and SuperPower present indications for bone thresholds of 55 and 65 dB respectively. We conducted a prospective observational study of a series of six cases with mixed hearing loss for whom implantation of the DAO Ponto(TM) Super-Power was performed. Tonal and verbal evaluations without and with background noise (HINTS) were performed prior to implantation and six months after adaptation. All the participants showed improvement in tonal and verbal results, varying according to the degree of contralateral hearing loss. The verbal results with background noise were noteworthy, where most of the patients obtained a signal-to-noise ratio between 2 and 4 dB. The results in the APHAB and GBI questionnaires showed a reduction in the perception of the problem and an improvement in quality of life respectively. The results presented reflect the possibility of treatment of mixed hearing loss with the Ponto(TM) SuperPower device