Individual computer-assisted 3D planning for placement of auricular prosthesis anchors in combination with an implantable transcutaneous bone conduction hearing device in patients with aural atresia.

BACKGROUND: The simultaneous implantation of the Bonebridge (MED-EL, Innsbruck, Austria), a semi-implantable active transcutaneous bone conduction hearing device and anchors for auricular prostheses can be challenging as both implants contain magnets and compete for the narrow space in the designated implantation area. MATERIAL AND METHODS: A preoperative planning tool (virtual surgery) was used with individual 3D computer models of the skull and implants for finding optimal implant positions for both the floating mass transducer (FMT) and the anchors for the auricular prosthesis. The interaction between the magnetic prosthesis anchors and the FMT was measured by means of static magnetic forces. A retrospective data analysis was conducted to evaluate the surgical and audiological outcome. RESULTS: Between 2014 and 2021, a 3D planning of a simultaneous implantation of the Bonebridge with auricular prosthesis anchors was conducted on 6 ears of 5 patients (3 males, 2 females; age range 17-56 years). The individual preoperative planning was considered very useful for the optimal placement of bone anchors in combination with the Bonebridge. Audiological data showed a clear benefit for hearing 3 months and > 11 months after implantation. No adverse interactions between the magnetic prosthesis anchors and the FMT were observed. In two patients, revision surgery was carried out due to skin inflammation or wound healing problems. No long-term complications were observed 3-5 years after surgery. CONCLUSION: Preoperative 3D planning represents a clear benefit for the simultaneous audiological and esthetic rehabilitation using the Bonebridge and anchors for auricular prostheses.

[Individual computer-assisted 3D planning for placement of auricular prosthesis anchors in combination with an implantable transcutaneous bone conduction hearing device in patients with aural atresia. German version]. / Individuelle computergestützte 3D-Planung zur Platzierung von Epithesenankern in Kombination mit einem implantierbaren transkutanen Knochenleitungshörgerät bei Patienten mit Ohrfehlbildungen.

BACKGROUND: The simultaneous implantation of the Bonebridge (MED-EL, Innsbruck, Austria), a semi-implantable active transcutaneous bone conduction hearing device and anchors for auricular prostheses can be challenging as both implants contain magnets and compete for the narrow space in the designated implantation area. MATERIAL AND METHODS: A preoperative planning tool (virtual surgery) was used with individual 3D computer models of the skull and implants for finding optimal implant positions for both the floating mass transducer (FMT) and the anchors for the auricular prosthesis. The interaction between the magnetic prosthesis anchors and the FMT was measured by means of static magnetic forces. A retrospective data analysis was conducted to evaluate the surgical and audiological outcome. RESULTS: Between 2014 and 2021 a 3D planning of a simultaneous implantation of the Bonebridge with auricular prosthesis anchors was conducted on 6 ears of 5 patients (3 males, 2 females; age range 17-56 years). The individual preoperative planning was considered very useful for the optimal placement of bone anchors in combination with the Bonebridge. Audiological data showed a clear benefit for hearing 3 months and > 11 months after implantation. No adverse interactions between the magnetic prosthesis anchors and the FMT were observed. In two patients, revision surgery was carried out due to skin inflammation or wound healing problems. No long-term complications were observed 3-5 years after surgery. CONCLUSION: Preoperative 3D planning represents a clear benefit for the simultaneous audiological and esthetic rehabilitation using the Bonebridge and anchors for auricular prostheses.

Comparative results of arthroscopic ankle arthrodesis vs. open arthrodesis in patients with diabetes-associated Charcot Neuro-Arthropathy.

BACKGROUND: Several studies demonstrated a considerable complication rate for open ankle or TTC arthrodesis in patients with diabetes, revision surgery and ulceration. Extensive approaches in combination with multimorbide patients have been suggested as the rationale behind the increased complication rate. METHODS: Single-centre, prospective case-control study compared arthroscopic vs. open ankle arthrodesis in patients with Charcot Neuro-Arthropathy of the foot. 18 patients with septic Charcot Neuro-Arthropathy Sanders III-IV received an arthroscopic ankle arthrodesis with TSF (Taylor Spatial Frame®) fixation combined with different additional procedures required for infect treatment and hindfoot realignment. The ankle arthrodesis was required for the realignment of the hindfoot in Sanders IV patients, arthritis or in case of infection. 12 patients were treated with open ankle arthrodesis and TSF fixation combined with various additional procedures. RESULTS: A significant improvement has been shown in radiological data in both groups. A significant lower complication rate has been registered in arthroscopic group. A significant correlation was seen between major complications and therapeutic anticoagulation as well as smoking. CONCLUSION: In high-risk patients with diabetes and plantar ulceration excellent results could be demonstrated in arthroscopically performed ankle arthrodesis with midfoot osteotomy using TSF as fixation devise.

Clinical and functional results after implantation of the bonebridge, a semi-implantable, active transcutaneous bone conduction device, in children and adults.

PURPOSE: Aim of the study was to evaluate the surgical, clinical and audiological outcome of 32 implantations of the Bonebridge, a semi-implantable transcutaneous active bone conduction implant. METHODS: In a retrospective cohort study, we analyzed data for 32 implantations in 31 patients (one bilateral case; seven age < 16 years) with conductive or mixed hearing loss, malformations, after multiple ear surgery, or with single-sided deafness as contralateral routing of signal (CROS). RESULTS: Four implantations were done as CROS. Five cases were simultaneously planned with ear prosthesis anchors, and 23 implantations (72%) were planned through three-dimensional (3D) "virtual surgery." In all 3D-planned cases, the implant could be placed as expected. For implant-related complications, rates were 12.5% for minor and 3.1% for major complications. Implantation significantly improved mean sound field thresholds from a preoperative 60 dB HL (SD 12) to 33 dB HL (SD 6) at 3 postoperative months and 34 dB HL (SD 6) at > 11 postoperative months (p < 0.0001). Word recognition score in quiet at 65 dB SPL improved from 11% (SD 20) preoperatively to 74% (SD 19) at 3 months and 83% (SD 15) at > 11 months (p < 0.0001). The speech reception threshold in noise improved from - 1.01 dB unaided to - 2.69 dB best-aided (p = 0.0018). CONCLUSION: We found a clinically relevant audiological benefit with Bonebridge. To overcome anatomical challenges, we recommend preoperative 3D planning in small and hypoplastic mastoids, children, ear malformation, and simultaneous implantation of ear prosthesis anchors and after multiple ear surgery.

Minimally invasive hallux valgus correction with Internal Hallux Fixator® - A comparative cadaver study.

BACKGROUND: The Internal Hallux Fixator® (IHF®; Waldemar Link, Hamburg, Germany) was designed for open surgical hallux valgus correction. It allows a defined lateralisation of the first metatarsal head after V-shaped, Chevron-like distal metatarsal osteotomy in order to correct mild to middle hallux valgus deformities. The intramedullary fixation provides dynamic compression of the osteotomy and thus postoperative full weight bearing mobilization is an integral part of the therapy. This comparative cadaver model study investigates the feasibility of implanting the device using a minimally invasive technique and compares its capability of first metatarsal head lateralisation to the established 3rd generation MICA (Minimally Invasive Chevron and Akin osteotomy) technique. METHODS: 16 fresh frozen cadaveric feet (8 left, 8 right) of 8 body donors received either MICA (Group 1), or an IHF® in a minimally invasive technique (Group 2). The achievable first metatarsal head lateralisation and operating time were measured and pitfalls recorded. RESULTS: This cadaver model study confirmed, the minimally invasive implantation of the Internal Hallux Fixator® can be performed reliably via 10 mm mini incision with V-shaped distal metatarsal osteotomy. The mean first metatarsal head lateralisation was comparable between the groups with no statistically significant difference (7.2 (±1.9) mm in G1, or 8.3 (±0.8) mm in G2; p = 0.09). The IHF® was inserted and fixed in mean 3.7 (±0.6) min, whereas double screw fixation needed 10 (±3.7) min. LEVEL OF CLINICAL EVIDENCE: 5, Cadaver model study.

Anatomical study of Lapidus arthrodesis using two different plantar plate systems.

BACKGROUND: First tarsometatarsal arthrodesis (modified Lapidus procedure) constitutes a sufficient treatment for moderate to severe hallux valgus deformity and first ray instability. The plantar plate arthrodesis was shown to provide superior mechanical stability and less postoperative complications than screw fixation or dorsal plating. Nevertheless, the in-brought hardware may cause irritation of the tibialis anterior or peroneus longus tendon requiring explantation of the material in some cases. The purpose of this study was to investigate the potential of tendon irritation after plantar first tarsometatarsal joint arthrodesis in a cadaver study. METHODS: Plantar plate arthrodesis was performed as in real surgery on twelve pairs of fresh frozen cadaveric feet. Two different plate systems were randomly allocated to each pair of feet. After plate fixation careful dissection of the feet followed to analyze potential tendon irritation and to determine a "safe zone" for plantar plate placement. RESULTS: A "safe zone" between the insertion sties of tibialis anterior and peroneus longus tendon was found and proven to be sufficiently exposed using a standard medio-plantar approach. Both plates were fixed in this zone without compromising central tendon parts. Peripheral tendon parts were irritated in 42% using Darco Plantar Lapidus Plating System® (Wright Medical, Memphis, TN) and in 8% using the Plantar Lapidus Plate® (Arthrex, Naples, FL). Bending of the anatomically preshaped plates is often necessary to ensure optimal fit on the bone surface. CONCLUSIONS: Modified Lapidus procedure with plantar plating of the first tarsometatarsal joint can be performed safely without compromising central tendon parts via standard medio-plantar approach. LEVEL OF CLINICAL EVIDENCE: 5, Cadaver Study.

Open vs Minimally Invasive Resection of the First Metatarsocuneiform Joint: An Anatomical Study.

BACKGROUND: The modified Lapidus arthrodesis is a standard procedure to correct middle to severe hallux valgus (HV) deformities. Recently, minimally invasive techniques of first metatarsocuneiform joint (MCJ) resection using a Shannon burr were described. The primary goal of this study is to compare the anatomical efficacy and safety of first MCJ resection using a straight 2 × 13-mm Shannon burr and minimally invasive technique (MIS) vs an open technique using an oscillating saw. METHODS: Ten pairs of fresh frozen cadaveric feet were randomly assigned to open or MIS first MCJ resection with subsequent systematic dissection. For the MIS procedure, a dorsomedial approach was used and for the open procedure a medioplantar approach was used. Cartilage removal was investigated by analyzing standardized scaled photographs of the resected articular surfaces with ImageJ software. Nearby structures at risk were analyzed for iatrogenic violation: tibialis anterior (TA), extensor hallucis longus (EHL) and peroneus longus (PL) tendons, and the Lisfranc ligament complex (LLC). RESULTS: In the MIS group, the median cartilage resection was 85.9% at the cuneiform and 85.6% at the metatarsal bone compared to 100% cartilage resection in open technique (P < .01). Iatrogenic damage of the LLC, EHL, and TA tendons was not found in any group. The PL tendon was thinned out (<25% of tendon thickness) in 4 cases (40%) in the open group and in 1 case (10%) in the MIS group. A safe zone of 3.0 mm between the articular surface of the cuneiform bone and the LLC was identified, which can be resected without putting the LLC at risk when performing lateral-based wedge resections. CONCLUSION: In this cadaver study with the procedures performed by an experienced foot and ankle surgeon, and using 2 different surgical approaches, we found general parity between the Shannon burr MIS technique vs oscillating saw open technique techniques with more risk to the PL with our open technique and approximately 15% less cartilage resection with our MIS technique. LEVEL OF EVIDENCE: Level V, cadaver study.

Minimally Invasive vs Open Akin Osteotomy.

BACKGROUND: Minimally invasive techniques of Akin osteotomy have grown in popularity, as early results suggest faster recovery, earlier return to work, and minimized wound healing problems. Preserving lateral cortex integrity during first phalanx osteotomy thereby presents a challenge because of the lack of direct visual control. This retrospective comparative study investigated clinical and radiographic outcomes of minimally invasive and open Akin osteotomy with different fixation methods and analyzed whether or not intraoperative violation of the lateral cortex caused loss of correction or delayed bone healing. METHODS: One hundred eighty-four patients (210 feet) with symptomatic hallux valgus and pathologic interphalangeal angle (IPA) of at least 10 degrees underwent surgery combined with Akin osteotomy. Minimally invasive Akin osteotomies were fixed in 124 feet with 2 crossing percutaneous K-wires and compared to 86 Akin osteotomies by open technique with double-threaded (head and shank) screw fixation. At 1 day and 6 and 12 weeks postoperatively, IPA and bony consolidation were radiographically and clinically assessed. RESULTS: Mean preoperative IPA was 13.4 ± 3.6 degrees in minimally invasive (MI) and 13.3 ± 3.5 degrees in open surgery (OS) cases (P > .05). Intraoperative breach of the lateral cortex occurred in 12 (13.9%) in OS and 64 (51.6%) in MI cases. Whereas the breach occurred in open technique mainly during manual correction by applying a medial closing force, it was caused predominantly by the use of the burr in minimally invasive technique. After 12 weeks, the mean IPA was 4.1 ± 1.4 degrees in MI and 4.8 ± 1.2 degrees in OS cases (P > .05). Bony consolidation was complete after 6 and 12 weeks in OS and MI, respectively. Three deep infections occurred in the OS Group after Lapidus arthrodesis and 2 deep infections were registered in the MI Group after minimally invasive chevron and Akin osteotomy. The infections were not at the site of the Akin osteotomy. CONCLUSION: Breach of the lateral cortex did not impair bone healing or correction of IPA. Minimally invasive Akin osteotomy with K-wire fixation provided equivalent correction of IPA compared to open surgery with screw fixation. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Changes in Bone Conduction Implant Geometry Improve the Bone Fit in Mastoids of Children and Young Adults.

OBJECTIVES: In 2012 the first active bone conduction implant was introduced, but did not fit into the mastoids of some adults and many children. Thus, a geometry change of the transducer was proposed (BCI 602). In this study, we aimed to determine whether these changes improved the mastoid cavity fit of the implant in children and young adults. DESIGN: We retrospectively analyzed computed tomography scans of 151 mastoids from 81 children and adolescents (age range, 5 mo to 20 yr) and 52 control mastoids from 33 adults. After three-dimensional reconstruction of the temporal bone from computed tomography, we virtually implanted the BCI 602 into the mastoids, and compared the bone fit with that of the BCI 601. RESULTS: The BCI 602 could be virtually implanted in 100% of patients ≥12 years old, while the BCI 601 transducer could be completely embedded in the bone of only 70% of these mastoids. Moreover, virtual implantation of the BCI 602 was possible in 75% of children 3 to 5 years of age, while the BCI 601 did not fit in the mastoids of any patients under 5 years old without the use of lifts. CONCLUSIONS: Compared to the BCI 601, placement of the BCI 602 allegedly requires less bone removal. The newer BCI 602 transducer is more likely than its predecessor to be completely accommodated in the mastoid bone among all age groups and indications. Preoperative planning is still recommended to avoid exposure of delicate structures.

Pain on the Plantar Surface of the Foot.

BACKGROUND: Plantar fasciitis (PF) is characterized by pain on weight-bearing in the medial plantar area of the heel, metatarsalgia (MTG) by pain on the plantar surface of the forefoot radiating into the toes. Reliable figures on lifetime prevalence in Germany are lacking. METHODS: This review is based on pertinent publications retrieved from a selective search in PubMed, on guidelines from Germany and abroad, and on the authors' clinical experience. RESULTS: Plantar fasciitis is generally diagnosed from the history and physical examination, without any ancillary studies. In 90-95% of cases, conservative treatment (e.g., stretching exercises, fascia training, ultrasound therapy, glucocorticoid injections, radiotherapy, shoe inserts, and shock-wave therapy) brings about total, or at least adequate, relief of pain within one year. Intractable pain is an indication for surgical treatment by plantar fasciotomy and/or calf muscle release. In metatarsalgia, a directed diagnostic work-up to find the cause is mandatory, including a search for excessive mechanical stress due to abnormal foot posture, neuropathic pain, rheumatoid arthritis, aseptic bony necrosis, or malignant disease; imaging studies and pedobarography are needed. For causally oriented treatment, a wide range of conservative and surgical measures can be considered. CONCLUSION: The reported results of treatments for plantar fasciitis and metatarsalgia are heterogeneous. The efficacy of the individual measures should be studied in randomized controlled trials.

A Three-Dimensional Geometric-Morphometric Study to Quantify Temporal Bone Growth and its Consequences for the Success of Implanting Bone Anchored Hearing Devices.

OBJECTIVE: A computed tomography (CT)-based morphological-investigation to describe temporal bone growth and to devise a predictive test of the likely success of Bonebridge implantation into the growing mastoid region of the temporal bone in young patients. STUDY DESIGN: Retrospective cross-sectional study. SETTING: University Hospital Halle (Saale), Germany. PATIENTS: Two cohorts participated. This first, of patients aged less than 21 years, comprised 42 men, and 33 women patients. The second cohort, for those aged more than or equal to 21 years, comprised 17 men, and 20 women patients. INTERVENTION: One hundred eighty three three-dimensional (3-D) reconstructions of the mastoid portion of the temporal bone without malformations or chronic middle ear disease were created on the base of high resolution computer tomography. The 3-D-reconstructions were analyzed using 13 linear measurements and volumetry. PRIMARY OUTCOME MEASURE: A CT/3-D model derived metric with which to best estimate the likely success of fitting a Bonebridge. RESULTS: Volume increase stagnated at, on average, 15.6 years of age (men), or 17.5 years (women). The most obvious extent of growth was observed in the craniocaudal direction from the middle cranial fossa to the tip of the mastoid process (total height). This growth is highly correlated with the increase of the mastoid volume (r = 0.938) and thus represents the most influential factor on mastoid volume increase. The total height of the mastoid portion can be used to usefully predict the chance of successful Bonebridge implantation.The depth of the mastoid almost doubled its size from birth (8.93 mm) to adulthood (16.34 mm) and also strongly affects the mastoid volume (r = 0.912). That portion between the external auditory canal (EAC) and the sigmoid sinus showed a lower growth capacity. CONCLUSIONS: The highly significant correlations between CT derived linear parameters and Bonebridge fitting (p < 0.001) can be used to estimate the success of Bonebridge implantation. The remarkable inter-individual variation of mastoid shape underlines the necessity of radiological preoperative planning.

Mastoid Dimensions in Children and Young Adults: Consequences for the Geometry of Transcutaneous Bone-Conduction Implants.

OBJECTIVES: Bone-conduction implants (BCI) are available for adults and children who are aged 5 years or more. Because a transcutaneous bone-conduction implant introduced in 2013 does not completely fit into all adult mastoids, we investigated mastoid dimensions and the possibility of fitting the implant in children. DESIGN: Computed tomography scans of 151 mastoids from 80 children and young adolescents from the age of 5 months to 20 years and 52 control mastoids from 33 adults were retrospectively analyzed. After three-dimensional reconstruction, mastoid volume was measured. The chances of fitting the Bonebridge or a novel BCI were determined as a function of age. Implant diameter and implantation depths were virtually varied to identify the most advantageous dimensions for reducing the minimum age for implantation. RESULTS: Mastoid volume increased to 13.8 ml in female and 16.4 ml in male adult mastoids at ages 18.9 years (male) and 19.0 years (female). Without compromising the middle fossa dura or the sinus and without lifts, the Bonebridge implant fit in 81% of male adult mastoids and 77% of the female adult mastoids. For children, the 50% chance of fitting a Bonebridge in the mastoids was reached at age 12 years; with a protrusion of 4 mm (4-mm lifts), this age was reduced to >6 years. The novel BCI fit in 100% of male and 94% of female adult mastoids. CONCLUSIONS: Casing diameter is the most limiting factor for Bonebridge implantation in children. A modified implant casing with a truncated cone and reduced diameter and volume would increase the number of hearing impaired children who can be rehabilitated with a Bonebridge implant. Radiological planning for Bonebridge implantation is necessary in all children.