Multi-electrode sequential versus single electrode stimulation to elicit the stapedial reflex during cochlear implantation: Correlation with maximum comfort level.

OBJECTIVES: To assess whether electrical stimulation sequentially delivered through 4 electrodes located in different cochlear areas may elicit the stapedial reflex at lower levels compared to single electrode stimulation and to correlate the sequentially obtained values with the maximum comfort level (C-level). PATIENTS AND METHODS: A retrospective study was performed on 35 post-verbal adult patients (age 19-80 years) consecutively implanted in 2 cochlear implant centers, evaluating the level of stimulation (pulse width) necessary to electrically evoke the stapedial reflex with two different stimulation modalities: single electrode versus sequential 4 electrode stimulation. Threshold values were compared with C-level obtained at activation. RESULTS: The average differences of pulse width and C-level were significantly smaller (P<0.0001) when the stapedial reflex was obtained with the sequential stimulation modality and reached statistical significance for every single electrode (P<0.0001). CONCLUSIONS: Stapedial reflex thresholds obtained with sequential stimulation through 4 different electrodes significantly correlate to the C-level obtained at the first setting and may be helpful in defining the upper limit of the dynamic field during initial CI mapping.

Cochlear implantation in chronic otitis media and previous middle ear surgery: 20 years of experience.

Cochlear implantation in the setting of chronic otitis media or previous middle ear surgery poses several problems for the surgeon: possible spread of infection to the cochlea and the subarachnoid spaces with consequent meningitis, risk of electrode array extrusion and possible recurrence of the original disease. Several surgical strategies have been proposed to overcome these problems. In the present study, clinical and functional results of cochlear implantation in 26 patients with chronic otitis media (8 cases) or previous middle ear surgery (18 cases) in the ear most suitable for implantation were retrospectively reviewed. Among the 8 patients with chronic otitis media, in 7 cases a subtotal petrosectomy associated with external auditory canal closure and mastoid and Eustachian tube obliteration was performed, while in the remaining patient cochlear implantation was done 6 months after a myringoplasty. The only complication observed was a reperforation of the tympanic membrane in this latter patient. Among the 18 patients with previous middle ear surgery, 2 had undergone intact canal wall tympanomastoidectomy and were implanted utilising the previous surgical approach. In the remaining 16 patients who had a radical cavity, an open technique was maintained in 3 cases; a cavity revision associated to external auditory canal closure, Eustachian tube and mastoid obliteration was performed in 12 patients, while in one case a middle cranial fossa approach was utilised. Two of the 3 patients in whom an open technique was maintained have experienced electrode array extrusion. The only complication observed in the remaining patients was the breakdown of the external auditory canal closure in one case. No problems were noted in patients who had undergone intact canal wall tympanomastoidectomy as well as in the subject implanted via the middle cranial fossa approach. All patients achieved and maintained good hearing performance over time. Subtotal petrosectomy associated with external auditory canal closure, Eustachian tube occlusion and mastoid obliteration is an effective procedure to facilitate cochlear implantation in presence of chronic otitis media. The open cavity technique offers the advantage of a close clinical examination, but may expose the patient to the risk of electrode array extrusion, mainly in the long-term period.

Long-term surgical and functional outcomes of the intact canal wall technique for middle ear cholesteatoma in the paediatric population.

In this paper, we report the postoperative outcomes in canal wall up procedures with second stage surgery in 40 children undergoing intervention for cholesteatoma of the middle ear. The residuals, recurrences and the hearing results were analysed. All 40 patients had a follow-up of at least five years. Of the 39 patients who underwent two staged surgery, 18 (46.1%) had a residual lesion that was identified and excised during the second surgery. Over a five year follow-up period, there were five (12.5%) patients with recurrences, all belonging to the group in whom a residual cholesteatoma was identified during the second staged surgery. The rate of residual cholesteatoma tends to decrease as age increases. The type of cholesteatoma, acquired or congenital middle ear, were not statistically related to the incidence of residual cholesteatoma. Hearing analysis showed that hearing recovery was excellent with canal wall up procedures and remained stable over five years.

Bilateral congenital cholesteatoma: report of an emblematic case.

OBJECTIVES: To describe a case of bilateral congenital cholesteatoma (CC) of the middle ear with a focus on diagnostic clues, treatment and a review of the pertinent literature. PATIENT AND METHODS: An 8-year-old child was incidentally noted to have whitish bilateral retrotympanic masses with normal hearing and referred to our department in January 2005. Microscopic examination of the ears and CT scan of the temporal bones led to a presumptive diagnosis of bilateral CC. The lesion on the right side was surgically removed, followed by that on the left side after 6 months; a retroauricular transcanal approach was adopted in both ears. RESULTS: Anatomic integrity of the middle ear was achieved with preservation of pre-operative hearing. No signs of recurrence were evident 20 months after the last surgery. CONCLUSIONS: Bilateral CC is a rare finding but otologists must be aware of it. Surgery must be planned early in order to achieve radical removal of the pathology and the preservation of middle ear structures.

Paget's disease and cochlear implantation.

Paget's disease of bone is a common disorder of unresolved etiology characterized by excessive bone resorption followed by excessive bone formation. If the skull is affected this may result in hearing loss and eventually develop into profound deafness. To date, no cases of cochlear implantation in patients with Paget's disease have been reported. The authors present a case of radiographically confirmed Paget's disease of the skull in a 77-year-old man with a 20-year history of progressive bilateral sensorineural hearing loss who underwent cochlear implantation. A successful insertion of the Nucleus 24 Contour electrode array was achieved without surgical and postoperative complications. At the 10 months' postoperative evaluation, the patient had gained useful open-set speech perception. In quiet conditions, his performance scores on the word and sentence recognition tests were 100 and 98 per cent, respectively. In the presence of noise (at +10 dB. signal-to-noise ratio), his performance scores on the word and sentence recognition tests were 96 and 94 per cent, respectively.

Speech recognition in elderly cochlear implant recipients.

The benefits of cochlear implantation in the adult and paediatric populations are well established. Cochlear implantation in the geriatric population still remains controversial because of the misconception that elderly patients might perform poorly. The purpose of this study was to report the speech performance of 16 patients over 65 years of age implanted with a Nucleus multichannel cochlear implant and to compare it with that of a control group of 14 adults aged between 41 and 59 years. At the 12 months postoperative evaluation, no significant differences were detected on speech performances between the elderly patients and the control group. The mean word recognition scores were 72.5% for the elderly group and 82% for the control group. The mean everyday sentence recognition scores were 72.5% for the elderly group and 85.7% for the control group. Overall, the results are encouraging and demonstrate that the elderly population with profound hearing loss obtain significant benefits from cochlear implantation despite the age-related auditory processing problems.

[Multi-channel cochlear implant in cochlear ossification]. / L'impianto cocleare multicanale nelle ossificazioni cocleari.

Cochlear ossification, considered until only a few years ago as a contraindication for cochlear implants (C.I.), may now be managed by means of a wide variety of surgical techniques. In cases with massive ossification, the drill-out circummodiolar technique described by Gantz et al. in 1988 and successively modified by Balkany et al. in 1997 may be adopted. The technique of electrode insertion in the scala vestibuli, perfected by Steenerson et al. in 1990, may be used when cochlear ossification has spread no further than the scala tympani. Other methods call for a groove to be drilled along the proximal tip of the basal turn of the cochlea (Cohen and Waltzman, 1993), the insertion of electrodes through the middle cranial fossa (Colletti et al., 2000), or the utilization of a double electrode array (Bredberg et al., 1997, Lenarz et al., 2001). This study reports the experience conducted at the Cochlear Implants Centre of the Otorhinolaryngoiatrics, Otological and Otoneurological Microsurgery Section of the University of Parma in a group of 15 patients who underwent C.I. in the presence of varying degrees of ossification. In 3 cases the ossification was limited to the region of the round window and a few millimetres of the scala tympani; cochleostomy was performed anteriorly and inferiorly to the anterior niche of the round window. In 11 cases (of which 3 of pediatric age), the ossification had spread to the horizontal portion of the scala tympani; in these cases, the electrodes were inserted in the scala vestibuli. The scala vestibuli was opened by drilling anteriorly to the round window and superiorly to the spiral ligament. In the only case of massively ossified cochlea, it was possible to partially insert the electrodes in a circum-modiolar tunnel. In the 12-month follow-up hearing test, the 3 patients with ossification of the round window region and the first millimetres of the scala tympani respectively averaged 61.6% in recognizing 2-syllable words and 59% in recognizing words embedded in phrases. The averages on the 12-month follow-up hearing test in the 8 adult patients who received the implant in the scala vestibuli were 80.6% in recognizing 2-syllable words and 89.1% in recognizing words in phrases. The 3 pediatric patients were classified on the Geers and Moog scale, which situated 2 of them in the 6th category of perception and 1 of them in the 4th category of perception. As regards the only case of massive cochlear ossification, the patient underwent surgery recently, and the sole follow-up available is the one conducted after only 3 months; the vowel identification average was 55%; the average on the VCV test was 31%; and the 2-syllable word recognition average was 20%.

Congenital cholesteatoma of the tympanic membrane.

We present two cases of congenital cholesteatoma of the tympanic membrane. Congenital cholesteatoma within the tympanic membrane is a rare entity with only few cases documented. The aetiopathogenesis of this lesion is still unknown. An embryologic origin is hypothesized when cholesteatoma develops in patients without previous history of otitis as in the two cases we report. In cases with previous history of inflammatory process of the external or middle ear an acquired origin is suspected due to the proliferation of the basal cell layer of the tympanic membrane epithelium. Despite the rarity of the congenital tympanic membrane cholesteatoma, we think that its early diagnosis is of utmost importance to allow an easy removal and avoid middle ear involvement.

Synergism between vascular endothelial growth factor and placental growth factor contributes to angiogenesis and plasma extravasation in pathological conditions.

Vascular endothelial growth factor (VEGF) stimulates angiogenesis by activating VEGF receptor-2 (VEGFR-2). The role of its homolog, placental growth factor (PlGF), remains unknown. Both VEGF and PlGF bind to VEGF receptor-1 (VEGFR-1), but it is unknown whether VEGFR-1, which exists as a soluble or a membrane-bound type, is an inert decoy or a signaling receptor for PlGF during angiogenesis. Here, we report that embryonic angiogenesis in mice was not affected by deficiency of PlGF (Pgf-/-). VEGF-B, another ligand of VEGFR-1, did not rescue development in Pgf-/- mice. However, loss of PlGF impaired angiogenesis, plasma extravasation and collateral growth during ischemia, inflammation, wound healing and cancer. Transplantation of wild-type bone marrow rescued the impaired angiogenesis and collateral growth in Pgf-/- mice, indicating that PlGF might have contributed to vessel growth in the adult by mobilizing bone-marrow-derived cells. The synergism between PlGF and VEGF was specific, as PlGF deficiency impaired the response to VEGF, but not to bFGF or histamine. VEGFR-1 was activated by PlGF, given that anti-VEGFR-1 antibodies and a Src-kinase inhibitor blocked the endothelial response to PlGF or VEGF/PlGF. By upregulating PlGF and the signaling subtype of VEGFR-1, endothelial cells amplify their responsiveness to VEGF during the 'angiogenic switch' in many pathological disorders.

Cochlear effects of mesna application into the middle ear.

Mesna (sodium 2-mercapto-ethane sulphonate) belongs to a class of thiol compounds that produce mucolysis by disrupting the disulphide bonds of the mucus polypeptide chains. The registered indications of mesna include the treatment of pathologies of the respiratory tract and, in oncology, the prevention of toxic lesions of the urinary tract by antineoplastic agents. In the E.N.T. Clinic of the University of Parma, it has been found that mesna can be used to facilitate the dissection of the various tissue layers in any surgical procedure. One of these indications is surgical treatment of cholesteatoma, which is mainly composed by keratin, a protein rich is disulphide bonds that are easily disrupted by mesna. The aim of this study was to evaluate the toxicity of mesna application into the middle ear on the cochlear anatomy and physiology. Three groups of guinea pigs were used as subjects. Mesna solution (10 or 20%) was applied in one ear, while the opposite ear received a placebo (saline solution). Toxicity of mesna was assessed by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and auditory brain-stem response (ABR). TEM and SEM did not show any toxic effect on cochlear morphology. There were no differences in ABR thresholds and wave III amplitude and latency between mesna-treated and control ears.

Adenovirus-mediated in vivo gene transfer in guinea pig middle ear mucosa.

This article describes a study designed to assess the feasibility of using recombinant adenovirus for delivering therapeutic peptides in vivo in the guinea pig middle ear cleft. A recombinant adenoviral vector AdCMVsp1 LacZ containing the Escherichia coli beta-galactosidase was injected into the middle ear space. Qualitative assessment of cell middle ear transfection was performed on day 2 by light microscopy study, after injecting a multiplicity of infection (MOI) ranging from 0 to 1000. At an MOI of 30, 30% of the promontory area epithelial cells were stained. An MOI of 50 stained 60% of the cells and an MOI of 100 or more stained more than 90% of the cells. The duration of cell transfection was studied after injecting an MOI of 50. The percentage of stained cells was 60% on day 2, 10% on day 7, and 0% on day 14. Middle ear mucosal inflammation, consisting of a granulocytic infiltrate, was observed when an MOI above 50 was used. Even at a high MOI (500), no staining could be found in the cochlea, in the facial nerve, in the brain, or in visceral organs. These data suggest that recombinant adenovirus vectors can be used to transfer genes in the middle ear. This method appears to be safe, and may be envisaged as a short-duration treatment to transfer genes in vivo in the treatment of middle ear diseases.

Human lymphoblastoid cells produce extracellular matrix-degrading enzymes and induce endothelial cell proliferation, migration, morphogenesis, and angiogenesis.

Human lymphoproliferative diseases can be hypothesized to invade locally and to metastatize via mechanisms similar to those developed by a variety of solid tumors, i.e., the secretion of extracellular matrix-degrading enzymes and stimulation of angiogenesis. To assess this hypothesis, Namalwa, Raji, and Daudi cell lines (Burkitt's lymphoma), LIK and SB cell lines (B-cell lymphoblastic leukemia), CEM and Jurkat cell lines (T-cell lymphoblastic leukemia), and U266 cell line (multiple myeloma) were evaluated for their capacity to produce matrix metalloproteinase-2 and -9, and urokinase-type plasminogen activator. These cell lines were also assessed for their ability: (1) to produce the angiogenic basic fibroblast growth factor and vascular endothelial growth factor; (2) to induce an angiogenic phenotype in cultured endothelial cells, represented by cell proliferation, chemotaxis, and morphogenesis; (3) to stimulate angiogenesis in different in vivo experimental models. All cell lines expressed the mRNA for one or both metalloproteinases. Namalwa, Raji, LIK, SB, and U266 cells secreted the active form of both metalloproteinases, while Daudi, CEM, and Jurkat cells produced metalloproteinase-2 but not-9. In contrast, urokinase-type plasminogen activator was secreted only by SB cells. While Raji, LIK, SB, CEM, and Jurkat cells secreted both basic fibroblast growth factor and vascular endothelial growth factor, Daudi and U266 cells produced only the former, and Namalwa cells only the latter. Accordingly, the conditioned medium of all cell lines stimulated cell proliferation and/or chemotaxis in cultured endothelial cells, with the exception of that of Namalwa cells which was ineffective. The conditioned medium of CEM and Jurkat cells induced morphogenesis in cultured endothelial cells grown on a reconstituted basement membrane (Matrigel). Lastly, Namalwa, Raji, LIK, SB, U266, CEM, and Jurkat cells induced angiogenesis and mononuclear cell recruitment in the murine Matrigel sponge model and in a chick embryo chorioallantoic membrane assay. The extent of angiogenesis in both models was strictly correlated with the density of the mononuclear cell infiltrate. The results indicate that human lymphoproliferative disease cells possess both local and remote invasive ability via the secretion of matrix-degrading enzymes and the induction of angiogenesis which is fostered by host inflammatory cells and by an intervening ensemble of angiogenic factors.

Placenta growth factor-1 is chemotactic, mitogenic, and angiogenic.

The placental-derived growth factor (PIGF) is a dimeric glycoprotein showing a high degree of sequence similarity to the vascular endothelial growth factor. Alternative splicing of the PIGF primary transcript gives rise to two forms, named PIGF-1 and PIGF-2, which differ only in the insertion of a highly basic 21-amino acid stretch at the carboxyl end. The presence of the PIGF mRNA in thyroid, placenta, lung, and goiter has indicated the tissues where this factor functions. However, the role of PIGF in vascular development has not yet been clearly established. In the present study, we described the purification of PIGF-1 from overexpressing eukaryotic cells and then measured the angiogenic activity of the purified PIGF-1 in vivo in the rabbit cornea and the chick chorioallantoic membrane assays. In both in vivo assays, PIGF-1 induced a strong neovascularization process that was blocked by affinity-purified anti-PIGF-1 antibody. In the avascular cornea, PIGF-1 induced angiogenesis in a dose-dependent manner and seemed to be at least as effective (if not more effective) than vascular endothelial growth factor and basic fibroblast growth factor under the same conditions and at the same concentration. PIGF-1 was shown to induce cell growth and migration of endothelial cells from bovine coronary postcapillary venules and from human umbilical veins. In these two in vitro assays, PIGF-1 seemed to have a comparable effect to that of vascular endothelial growth factor and basic fibroblast growth factor on the cultured microvascular endothelium (eg, capillary venule endothelial cells). In summary, this is the first study to demonstrate that PIGF-1 can induce angiogenesis in vivo and stimulate the migration and proliferation of endothelial cells in vitro.

Assignment of the vascular endothelial growth factor gene to human chromosome 6p21.3.

BACKGROUND: Vascular endothelial growth factor (VEGF) is an endothelial cell-specific growth factor and a regulator of physiological and pathological angiogenesis. Four different proteins are produced by alternative splicing of a unique transcript generated from a single-copy gene. Knowledge of the chromosomal location of the VEGF gene would help in determining a linkage to any known human congenital syndrome and/or to known chromosomal rearrangements in tumors. METHODS AND RESULTS: A human chromosome mapping panel was used to assign the VEGF gene to human chromosomes by polymerase chain reaction using VEGF-specific oligonucleotide primers. Amplified DNA fragments were fractionated on a 1% agarose gel. A single band of the expected size was obtained only from the DNA of those hybrid cell lines that contained the human chromosome 6. Three YAC clones containing the VEGF gene were obtained by screening the ICI Diagnostics library. In situ hybridization was then used to locate the VEGF gene in the 6p21.3 region. CONCLUSIONS: The location of the VEGF gene in the 6p21.3 region is a potential starting point for a linkage study. In addition, the isolation of YAC clones containing the VEGF gene will contribute to the construction of the physical map of this chromosomal region.

Laparoscopic Placement of Adjustable Silicone Gastric Band in the Treatment of Morbid Obesity: How to Do It.

BACKGROUND: laparoscopic placement of the adjustable silicone gastric band (ASGB) was begun in our institution in 1992. METHODS: this work started on the animal model first. In the animal laboratory, details of laparoscopic dissection around the pig's stomach were defined. A new prototype of the adjustable silicone band for laparoscopic use was devised. The first human laparoscopic ASGB procedure was performed in our institution on September 1, 1993; 37 patients have undergone this operation by May, 1994. There were 33 women and four men. The average pre-operative weight was 114 kg (92160 kg). The mean BMI was 42 kg m(2) (37-50 kg m(2)). RESULTS: no major operative difficulty has been encountered. Immediate post-operative outcome was uneventful except for one patient. CONCLUSION: the technique of laparoscopic ASGB is described. Preliminary weight loss is comparable to open ASGB and vertical gastroplasty, provided that the surgeon has mastered laparoscopy and open bariatric surgery.