Gösta Granström

Bone-anchored hearing aids: current status in adults and children.

The BAHA is the only cochlea stimulator in clinical use using bone conduction as the mode of stimulation. Sound transmitted through bone conduction is a natural way of hearing and the fundamentals of bone conduction are presented. The simple but important procedure has been refined and is presented in some detail. As the BAHA is approved by the Food and Drug Administration for children, aspects relevant for this age group will be addressed. The future includes semi-implantable BAHA, percutaneous electrical coupling, and a BAHA for tinnitus suppression.

Osseointegrated implants in irradiated bone: A case-controlled study using adjunctive hyperbaric oxygen therapy

PURPOSE The current investigation was undertaken to study whether osseointegration of implants in irradiated tissues is subject to a higher failure rate than in nonirradiated tissues. It further aimed to study whether hyperbaric oxygen treatment (HBO) can be used to reduce implant failure. PATIENTS AND METHODS Seventy-eight cancer patients who were rehabilitated using osseointegrated implants between 1981 and 1997 were investigated. Three groups of patients were compared: irradiated (A), nonirradiated (B), and irradiated and HBO-treated (C). In addition, 10 irradiated patients who had lost most of their implants received new ones after HBO treatment. These were compared as a case-control group. RESULTS Implant failures were highest in group A (53.7%). Implant failure was 13.5% in group B and 8.1% in group C. The difference between group A and the other two groups was statistically significant (P = .001 to .0023, Mantells test). HBO significantly improved implant survival in the case-control group from 34 of 43 implants lost to 5 of 42 lost (P = .0078). CONCLUSIONS Implant insertion in irradiated bone is associated with a higher failure rate. Adjuvant HBO treatment can reduce the failures.

Osseointegrated Implants in Children: Experience from Our First 100 Patients:

This study was undertaken on 100 children aged 16 years or under intended for installation of osseointegrated implants. Of these, 76 had implants installed for bone-anchored hearing aids or prostheses. The main indication for implant installation was a bilateral ear malformation. Surgery was generally performed as a two-stage procedure with a healing time of 3 to 4 months in between. Available bone thickness was on average 2.5 mm, and lack of bone necessitated bone augmentation in 12 patients. Thirty-nine percent of implants were installed in contact with the dura, sigmoid sinus, or an air cell. Implant failures were 5.8% of 170 inserted fixtures. Adverse skin reactions appeared in 9.1% of patients over a 21-year follow-up period. Revision surgery was undertaken in 22% of patients because of appositional growth of the temporal bone. Of the 24 children considered but not found suitable for osseointegration surgery, plastic surgery was considered a better option, or growth of the temporal bone was awaited. It is concluded that the rate of implant failure is lower in children; the frequency of skin reactions is the same as in adults, but revision surgery is more common in young patients because of new bone formation. Our clinical experience supported by the data presented in this article suggests that the concept could be used with good functional and aesthetic results in children.

Hyperbaric Oxygen and Radiotherapy

Background:Hyperbaric oxygen (HBO) therapy is the inhalation of 100% oxygen at a pressure of at least 1.5 atmospheres absolute (150 kPa). It uses oxygen as a drug by dissolving it in the plasma and delivering it to the tissues independent of hemoglobin. For a variety of organ systems, HBO is known to promote new vessel growth into areas with reduced oxygen tension due to poor vascularity, and therewith promotes wound healing and recovery of radiation-injured tissue. Furthermore, tumors may be sensitized to irradiation by raising intratumoral oxygen tensions.Method:A network of hyperbaric facilities exists in Europe, and a number of clinical studies are ongoing. The intergovernmental framework COST B14 action “Hyperbaric Oxygen Therapy” started in 1999. The main goal of the Working Group Oncology is preparation and actual implementation of prospective study protocols in the field of HBO and radiation oncology in Europe.Results:In this paper a short overview on HBO is given and the following randomized clinical studies are presented:a) reirradiation of recurrent squamous cell carcinoma of the head and neck after HBO sensitization;b) role of HBO in enhancing radiosensitivity on glioblastoma multiforme;c) osseointegration in irradiated patients; adjunctive HBO to prevent implant failures;d) the role of HBO in the treatment of late irradiation sequelae in the pelvic region.The two radiosensitization protocols (a, b) allow a time interval between HBO and subsequent irradiation of 10–20 min.Conclusion:Recruitment of centers and patients is being strongly encouraged, detailed information is given on www.oxynet.org.Hintergrund:Unter „hyperbarer Sauerstofftherapie“, auch „hyperbare Oxygenation“ (HBO) genannt, versteht man die Atmung von 100% Sauerstoff bei einem Druck von mindestens 1,5 ATA (absolute Atmosphären; 150 kPa). Bei der HBO wird das Medikament Sauerstoff durch erhöhten Umgebungsdruck physikalisch im Plasma gelöst und unabhängig vom Hämoglobin in das Gewebe transportiert. Die HBO unterstützt in schlecht durchbluteten bestrahlten Geweben mit verringerter Sauerstoffspannung die Gefäßneubildung und trägt zur Wundheilung und Erholung des bestrahlten Gewebes bei. Andererseits kann Sauerstoff unter hyperbaren Bedingungen—während oder kurz vor der Strahlentherapie verabreicht—durch Erhöhung der intratumoralen Sauerstoffspannung als Radiosensitizer eingesetzt werden.Methodik:In Europa existiert ein Netzwerk von Druckkammern, an denen klinische Studien laufen. Im Jahr 1999 wurde das europäische Projekt COST B14 „Hyperbare Sauerstofftherapie“ gestartet. Das Hauptziel der Arbeitsgruppe „Onkologie“ ist die Vorbereitung und Implementierung klinischer Studienprotokolle, die sich mit dem Thema „HBO und Strahlentherapie“ beschäftigen.Ergebnisse:Die vorliegende Arbeit gibt einen kurzen Überblick über die Grundlagen und Wirkweise der HBO und stellt folgende zur Rekrutierung offenen randomisierten klinischen Studien vor:a) erneute Bestrahlung rezidivierter Plattenepithelkarzinome im Kopf-Hals-Bereich nach HBO-Sensibilisierung;b) HBO zur Erhöhung der Strahlensensibilität des Glioblastoma multiforme;c) Osseointegration nach Bestrahlung im Hopf-Hals-Bereich—adjuvante HBO zur Verhinderung der Implantatabstoßung;d) HBO bei radiogenen Spätfolgen im Beckenbereich.Die zwei Protokolle zur Strahlensensibilisierung (a, b) erlauben einen Zeitabstand zwischen HBO und nachfolgender Bestrahlung von 10–20 min.Schlussfolgerung:Interessierte Zentren werden eingeladen, sich aktiv an den Studien zu beteiligen (Details s. www.oxynet.org).

Oculo-auriculo-vertebral spectrum: associated anomalies, functional deficits and possible developmental risk factors.

Swedish patients with the oculo‐auriculo‐vertebral (OAV) spectrum participated in a prospective multidisciplinary investigation. The aims of the study were to describe their systemic and functional defects, especially autism spectrum disorders, and to search for possible etiologic risk factors. Available medical records were studied and the mothers answered a questionnaire on history of prenatal events. A clinical examination evaluating systemic findings, vision, hearing, speech, oral and swallowing function, and neuropsychiatric function, especially autism, was made. Eighteen patients, (11 males, 7 females) aged 8 months to 17 years with OAV were studied. Most frequent systemic malformations included, ear abnormalities (100%), ocular malformations (72%), vertebral deformities (67%), cerebral anomalies (50%), and congenital heart defects (33%). Functional defects consisted of hearing impairment (83%), visual impairment (28%), both visual and hearing impairment (28%), difficulties in feeding/eating (50%), speech (53%), mental retardation (39%), and severe autistic symptoms (11%). Three children were born following assisted fertilization (two intracytoplasmatic sperm injection, one in vitro fertilization), two mothers reported early bleedings, and six (33%) mothers had smoked during pregnancy.

Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation.

Objectives Since the technique to implant bone‐anchored hearing aids (BAHAs) with the use of osseointegrated implants was developed in 1977, more than 15,000 patients have been fitted with BAHAs worldwide. Although the majority have bilateral hearing loss, they are primarily fitted unilaterally. The main objective of this study was to reveal benefits and drawbacks of bilateral fitting of BAHAs in patients with symmetric or slight asymmetric bone‐conduction thresholds. The possible effects were divided into three categories: hearing thresholds, directional hearing, and binaural hearing.

Transmission of bone-conducted sound in the human skull measured by cochlear vibrations

One limitation with the Bone Anchored Hearing Aid (Baha®) is too poor amplification for patients with moderate to severe sensorineural hearing losses. Therefore, we investigated if bone conducted (BC) sound transmission improves when the stimulation approaches the cochlea. Also the influence from the squamosal suture on BC sound transmission was investigated. Both sides of the heads on seven human cadavers were used and vibrational stimulation was applied at eight positions on each side with a frequency range of 0.1–10 kHz. A laser Doppler vibrometer was used to measure the resulting velocity of the cochlear promontory. It was found that the velocity of the promontory increases as the stimulation position approaches the cochlea; this was especially apparent at distances within 2.5 cm from the ear canal opening and when the stimulation position was in the opened mastoid. At frequencies above 500 Hz there was on average 10 to 20 dB greater vibrational response at the cochlea when the stimulation was close to the cochlea compared with the normal Baha® position. Moreover, even if there were general indications of attenuation of BC sound when passing the squamosal suture, an effect from the suture could not be conclusively determined.

The bone-anchored hearing aid and bone-anchored epithesis for congenital ear malformations.

Surgery for correction of aural atresia was performed on 156 ears in 111 patients. A comparison was made between plastic surgery for auricular reconstruction and the bone-anchored epithesis. Another comparison was performed between hearing Improvement after reconstructive surgery for meatal and middle ear atresia and the bone-anchored hearing aid. It was found that the bone-anchored epithesis is an excellent alternative to plastic reconstructive surgery of the auricle. The bone-anchored hearing aid could be considered as a strong alternative to surgery in patients with meatal and middle ear atresia – especially in patients with advanced malformations. Neither the bone-anchored epithesis nor the bone-anchored hearing aid excludes the patient from reconstructive surgery later in life.

The relationship between cervical cysts and tonsillar carcinoma in adults

An investigation of the clinical results in 42 patients with lateral cervical cysts is presented. Fine needle aspiration biopsy suggested malignancy in three cases. After surgical removal, another six cases of malignancy were revealed by histologic examination. In six of the nine cases of malignancy, an ipsilateral tonsillar carcinoma was found on routinely performed tonsillectomy. However, the clinical appearance of the tonsils was normal in four of these patients. Analysis of all patients according to age revealed that the malignancy rate was 80% among those aged greater than 40 years. It is suggested that tonsillectomy for histologic examination should be performed routinely when lateral cervical cysts are removed in adults.

The bone-anchored hearing aid in children: a surgical and questionnaire follow-up study.

OBJECTIVES: The main objectives were to evaluate the surgical techniques and problems seen in children with bone-anchored hearing aids (BAHA) as well as to determine the childrens attitudes toward BAHA. STUDY DESIGN: A retrospective study of 41 children with unilateral BAHA was conducted. Surgical recordings were investigated and a questionnaire was distributed. RESULTS: Surgery was performed as a 2-stage procedure. Available bone thickness was measured in 29 patients and found to be on average 2.5 mm. Thin temporal bone necessitated bone augmentation in 8 patients. Of the implants, 70.5% were installed in contact with the dura or the sigmoid sinus. Implant failures were seen in 9.1% and adverse skin reactions appeared in 7.6% of the patients. Twenty-seven patients responded to the questionnaire, 19 were still BAHA users. Overall, these patients were very content with their BAHAs. CONCLUSION: BAHA is a good alternative in children despite limited thickness of the temporal bone.