New insights into tip supporting structures. Consequences for nasal surgery.

BACKGROUND: Knowledge of tip supporting structures is crucial for successful rhinoplastic surgery. The aim of this study was to provide detailed anatomical and histological descriptions of the tip supporting structures. METHODS: Serial coronal sections of the entire external noses from seven cadavers were studied after staining by Mallory-Cason and Verhoeff-Van Gieson procedures. RESULTS AND CONCLUSIONS: We found no histological evidence of ligaments between the cartilaginous- and bony parts of the nasal skeleton, and between the skin and the nasal skeleton. Instead, we found a perichondrial-periosteal lining within the soft tissue envelope. The main tip supporting and shaping structures are: septal and lobular cartilages, premaxillae, and the soft tissue envelope including the periosteal-perichondrial envelope/membrane. These findings may have clinical relevance in functional and aesthetic rhinoplasties.

Functional anatomy of the nasal bones and adjacent structures. Consequences for nasal surgery.

The periosteum of the nasal bones, the periosteal-perichondrial nasal envelope, and the cartilaginous support of the bony vault were studied in serial coronal sections of four human cadaver noses. To differentiate between the various tissue components, the sections were stained according to Mallory-Cason and Verhoeff-Van Gieson stain. The results demonstrated: 1. the presence of clearly distinguishable layers of the periosteum covering the nasal bones; 2. the presence of a continuous periosteal-perichondrial covering of the bony and cartilaginous nasal vaults; 3. the way the cartilaginous support of the bony vault is constructed. The findings described in the present study may have clinical relevance in nasal surgery.

Preoperative imaging protocol for cochlear implant candidates.

OBJECTIVE: To formulate and test a CT imaging protocol for preoperative scanning of the temporal bone in cochlear implant candidates. MATERIAL AND METHODS: A human head was scanned in three CT planes: axial, axiopetrosal and semilongitudinal. Multiplanar reformats (MPRs), based on axial slices, were created and compared with the corresponding images obtained by direct scanning in the respective planes. All scans were analyzed on a viewing workstation. RESULTS: The axial plane image allowed for an overview of the temporal bone. The width of the facial recess and the cochlear nerve canal could be studied on combined axial and axiopetrosal images. Cochlear patency could be evaluated using combined axial and semilongitudinal images. Axiopetrosal and semilongitudinal MPRs were able to replace the images obtained by direct scanning in the respective planes. CONCLUSION: The combination of the axial CT plane image and MPRs was found to be sufficient for preoperative analysis of the temporal bone morphology.

Dose-dependent effect of 8-day cisplatin administration upon the morphology of the albino guinea pig cochlea.

Numerous studies investigating cisplatin ototoxicity in animals have been performed, but it is difficult to derive a clear dose-effect relation from these studies. The degree of cisplatin-induced ototoxicity depends on a multitude of factors. Many parameters, such as dose, mode of administration, dosage schedule and concomitant administration of protective additives, vary among the published studies. Therefore, we performed a basic dose-effect study on cisplatin ototoxicity in the guinea pig. Albino guinea pigs were treated with cisplatin at daily doses of either 0.7, 1.0, 1.25, 1.5 or 2.0 mg/kg for 8 consecutive days. Electrocochleography was performed on day 10 after which the cochleas were removed and processed for histological examination. The electrophysiological results showed a marked transition from almost no ototoxic effect to a large effect between a daily dose of 1.25 and 1.5 mg/kg (Stengs et al., 1998). Outer hair cell (OHC) counts corresponded well with the electrophysiological results. At daily doses of 0.7, 1.0 and 1.25 mg/kg no statistically significant OHC loss was observed, whereas OHC loss averaged 60% and 65% in the basal turns at daily doses of 1. 5 and 2.0 mg/kg, respectively. Morphological changes in the stria vascularis were present only in cochleas from animals treated with cisplatin doses of 1.0, 1.25 and 1.5 mg/kg/day. Cochleas from animals treated with a daily cisplatin dose of 2.0 mg/kg for 8 consecutive days showed an endolymphatic hydrops. The present study shows that cisplatin, administered at a daily dose of 1.5 mg/kg for 8 consecutive days, provides a degree of OHC loss that is well suited to study the effects of putative protective agents and possible hair cell recovery.

Cisplatin-induced ototoxicity: morphological evidence of spontaneous outer hair cell recovery in albino guinea pigs?

Cisplatin is frequently used in the treatment of various forms of malignancies. Its therapeutic efficacy, however, is limited by the occurrence of sensorineural hearing loss. Little is known about the course of hearing loss over longer time intervals after cessation of cisplatin administration. Infrequently, recovery of hearing has been described in animals and humans. Stengs et al. (1997) treated guinea pigs with cisplatin at a daily dose of 1.5 mg/kg for 8 consecutive days and subsequently studied cochlear function after survival times varying from 1 day to 16 weeks. Spontaneous improvement of the hair cell-related potentials (cochlear microphonics and summating potentials) was observed starting 2 weeks after cessation of treatment. In the present study we examined light microscopically the cochleas used in the study of Stengs et al. (1997). One day after cessation of cisplatin administration outer hair cell (OHC) loss in the basal cochlear turn averaged 66%. In the 1-week survival group, OHC counts were similar to those of the 1-day survival group. In the 4-week survival group, however, a relatively small loss of OHCs was found in the basal cochlear turn; OHC loss averaged only 15%. A similar loss was found after 8 weeks. In the 16-week survival group, OHC loss in the basal turn increased to 48%, but this was not statistically significant. Our histological observations are in line with the electrophysiological data from the same animals. Our findings suggest that OHCs recover from cisplatin-induced damage 1-4 weeks after treatment. However, the results do not allow a conclusion as to whether the observed recovery is due to the formation of new OHCs or to (self-)repair of damaged OHCs.

Histological effects of co-administration of an ACTH((4-9)) analogue, ORG 2766, on cisplatin ototoxicity in the albino guinea pig.

Cisplatin is one of the most potent antineoplastic drugs presently known, but its therapeutic efficacy is seriously limited by several side effects such as ototoxicity. Several compounds that are known for their nephroprotective effects also seem to reduce the incidence and severity of cisplatin-induced ototoxicity. Hamers et al. (1994) and De Groot et al. (1997) investigated the possibly protective effect of concomitant administration of the ACTH((4-9)) analogue ORG 2766 upon cisplatin ototoxicity in guinea pigs. Animals were treated with cisplatin at a daily dose of 2.0 mg/kg for 8 consecutive days and ORG 2766 at a daily dose of 75 mcg/kg for 9 days. Concomitant administration of cisplatin plus ORG 2766 resulted in a bimodal distribution of the electrophysiological data (compound action potential and cochlear microphonics amplitudes) and the histological data (outer hair cell (OHC) counts). It was surmised that this dichotomy might occur at a certain cisplatin dose. We investigated whether this protective effect of ORG 2766 could be enhanced by reducing the daily dose of cisplatin while maintaining the same dose of ORG 2766. Thirty-six animals were treated with daily i.p. injections of cisplatin at a dose of 1.0 mg/kg (n=18) or 1.5 mg/kg (n=18) for 8 consecutive days. When comparing the mean OHC counts of the different experimental groups, treatment with cisplatin at a daily dose of 1.5 mg/kg for 8 consecutive days resulted in a considerable loss of OHCs, which was significantly reduced after co-administration of ORG 2766. Co-treatment with ORG 2766 did not result in a change in the volume of the scala media. The present results are in agreement with the electrophysiological results published earlier (Stengs et al., 1998b).

Treatment of inferior turbinate pathology: a review and critical evaluation of the different techniques.

At least 13 surgical techniques have been used over the past 130 years to treat hypertrophy of the inferior turbinate. These methods are reviewed and critically analyzed in this article. Our review of the literature revealed a serious lack of qualified studies. Research meeting the criteria for a prospective comparative randomized surgical study is extremely rare. In our opinion, the purpose of surgically reducing the inferior turbinates should be to diminish complaints while preserving function. From that perspective, it seems that electrocautery, chemocautery, (subtotal) turbinectomy, cryosurgery, and laser surface surgery should not be used, as these techniques are too destructive. Intratubinal turbinate reduction (intraturbinal turbinoplasty) would seem to be the method of choice.

Functional anatomy of the premaxillary area.

Although the gross anatomy of the nasal septum is well-understood, the exact anatomy of its ventrocaudal or premaxillary area is not. More precisely, there is some confusion about the course of the perichondrial and periosteal fibers in this particular region. This paper considers the detailed anatomy of the chondro-spinal and chondro-premaxillary junction. Six cadaver noses were sectioned in the coronal (n = 4) or the transverse (n = 2) plane. The sections were stained according to the Mallory-Cason and the Haematoxylin-Eosine method and examined by light microscopy. At the chondrospinal junction a relatively wide suture line filled with loose connective tissue fibers was found. The caudal margin of the cartilaginous septum is flanked by paraseptal cartilages. These broaden the septal base to fit onto the flat cranial surface of the anterior nasal spine. At the chondro-premaxillary junction a narrow suture with several crossing fibers between the perichondrium and periosteum was seen. Paraseptal cartilages, surrounded by their own perichondrium, cover the periphery of this area. It was concluded that the chondro-spinal junction provides stabilization while allowing some mobility of the septum, whereas the chondro-premaxillary complex stabilizes the septum without allowing mobility.

Validation of animal experiments on ciliary function in vitro. I. The influence of substances used clinically.

In vitro studies of ciliary activity require specimens of healthy epithelium in relatively large quantities. Since human material is difficult to obtain, fresh chicken trachea samples have frequently been used in function experiments. The aim of the present study was to investigate whether several substances had comparable effects on the ciliary beat frequency (CBF) of chicken trachea and cryopreserved human respiratory epithelium obtained from the sphenoidal sinus. For this study, we used two topical anaesthetics: cocaine (3% and 7%) and lidocaine (2%). These anaesthetic substances were adjusted to pH 6 and pH 7. We also used two decongestants, namely xylometazoline 0.1% and oxymetazoline 0.1%, and the beta-blocking agent propranolol. Topical anaesthetics appeared to be more ciliostatic in solutions with pH 7 compared to pH 6. Complete ciliostatic effects were reversible, with the exception of the ciliostasis induced by propranolol. The effects of these substances on the CBF of fresh chicken trachea and cryopreserved human tissue did not differ significantly. These experiments show that chicken trachea constitutes a valid substitute for human material in studying ciliary activity in vitro. Moreover, the experiments provide evidence in support of the assumption that cryopreservation has no effect on ciliary reactivity as expressed by the CBF.

Validation of animal experiments on ciliary function in vitro. II. The influence of absorption enhancers, preservatives and physiologic saline.

Ciliary beat frequency (CBF) is one of the most important parameters of mucociliary clearance. Previously, we demonstrated that mucosa from chicken embryo trachea is a good substitute for human ciliated epithelium to study the effects on CBF of substances that are used clinically. In this study, we examined the effect on CBF of four excipients for nasal drug formulations: the absorption enhancers methylated beta-cyclodextrin 2% and sodium taurodihydrofusidate 1%, the preservative benzalkonium chloride 0.01%, and physiologic saline. We also examined the effect on CBF of the cryopreservative dimethyl sulfoxide, which is used to protect ciliated epithelium prior to storage in liquid nitrogen. Results obtained with chicken embryo trachea were compared with those of cryopreserved human mucosa taken from the sphenoidal sinus. For all of the substances tested, the effects on CBF of chicken material were comparable to those measured on human material. Benzalkonium chloride had a stronger ciliostatic effect on human tissue. After 60 min, however, the effect of that substance on CBF was similar in both tissues. We conclude that chicken embryo trachea can be used as a substitute for human ciliated mucosa when studying ciliary activity in vitro.

Physiologic and hypertonic saline solutions impair ciliary activity in vitro.

OBJECTIVE/HYPOTHESIS: Physiologic saline (NaCl 0.9%) is commonly used in treating acute and chronic rhinosinusitis. Moreover, physiologic saline is used as a control medium, vehicle, or solvent in studies on ciliary beat frequency (CBF). Hypertonic saline (NaCl 7% and 14.4%) has been applied in attempts to enhance mucociliary transport in patients with cystic fibrosis or asthma and in healthy subjects. Therefore the objective of this study is to document in vitro effects of saline solutions in different concentrations on CBF. STUDY DESIGN: Experimental, in vitro. METHODS: The effects on CBF of cryopreserved mucosa of the sphenoidal sinus was measured by a photoelectrical method. Initial frequencies, measured in Locke-Ringer's solution (LR), were compared with CBF after exposure to NaCl in concentrations of 0.9%, 7.0%, and 14.4% (w/v). RESULTS: NaCl 0.9% has a moderately negative effect on CBF. The 7% solution leads to a complete ciliostasis within 5 minutes, although this effect turns out to be reversible after rinsing with LR. A hypertonic solution of 14.4% has an irreversible ciliostatic effect. CONCLUSION: LR is an isotonic solution that has no effect on CBF. Therefore it is probable that this solution is more appropriate than saline for nasal irrigation and nebulization or antral lavage. Moreover, the results of this study suggest that mucolytic effects induced by hyperosmolarity should be attained preferably with hypertonic saline 7% in patients with cystic fibrosis or asthma. At this concentration, the ciliostatic effect is reversible, whereas irreversible changes are to be expected at higher concentrations.

Cisplatin ototoxicity. An electrophysiological dose-effect study in albino guinea pigs.

Recently, the effect of the ACTH(4-9) analog, ORG2766, on cisplatin ototoxicity was studied by Hamers et al. (1994). This study showed that the ACTH(4-9) analog partially prevents the ototoxicity of cisplatin. The authors suggested that the daily dose of 2.0 mg/kg/day for 8 days might have been too high to obtain full protection. Knowledge about dose-effect relations for cisplatin ototoxicity is rather meager. Therefore, we conducted a basic dose-effect study for cisplatin without any concomitant additives. A follow-up of the Hamers et al. (1994) study, based on dose-effect data from this paper, is presented in a companion paper. The effects of cisplatin on the compound action potential (CAP), cochlear microphonics (CM) and summating potential (SP) were determined in acute experiments, in different groups of albino guinea pigs, each group injected with a different dose of cisplatin. Daily doses ranged from 0.7 to 2.0 mg/kg/day cisplatin (i.p.) for 8 consecutive days. Electrocochleography was performed at day 10. The measurements were performed over a broad range of frequencies (0.5-16 kHz). The results showed clustering of the data in two groups, the first group concerning the treatments of 1.5 and 2.0 mg/kg/day with large frequency-dependent losses in the three cochlear potentials, the second group concerning the treatments with lower doses of cisplatin (0.7, 1.0 and 1.25 mg/kg/day) where almost no losses in the three cochlear potentials were found. The threshold curves regarding the lower doses (0.7-1.25 mg/kg/day) were almost indistinguishable from the control threshold curve except at the higher frequencies (12 and 16 kHz). Thus, a marked transition from almost no ototoxic effect to a large effect seems to occur between cisplatin doses of 1.25 and 1.5 mg/kg/day for 8 days. The small difference between the effects found for 1.5 mg/kg/day and 2 mg/kg/day suggests that a smaller dose than the one of 2 mg/kg/day for 8 days used previously (Hamers et al., 1994) might better suit research into protection against cisplatin ototoxicity.

Protective effects of a neurotrophic ACTH(4-9) analog on cisplatin ototoxicity in relation to the cisplatin dose: an electrocochleographic study in albino guinea pigs.

Cisplatin is a potent cell cycle non-specific chemotherapeutic agent that produces side effects including high-frequency hearing loss. Hamers et al. (1994) studied electrophysiologically the effect of an ACTH(4-9) analog, also known as ORG2766, on the ototoxicity of cisplatin (administered at 2 mg/kg/day for 8 days) in guinea pigs. ORG2766 was given concomitantly with cisplatin during the 8 day period and an additional dose was given on day 9. The conclusion of this study was that ORG2766 might partially prevent cisplatin ototoxicity, but that the chosen cisplatin dose (2 mg/kg/day; 8 days) might have been too high. Because of the high cisplatin dose the protective power of the co-treatment with ORG2766 might not have stretched to all animals. In this study the results of co-treatment with the same dose and daily schedule of ORG2766 and cisplatin doses of 1.0 mg/kg/day and 1.5 mg/kg/day for 8 days are presented. The measurements were performed over a broad range of frequencies (0.5-16 kHz). Electrocochleography was performed at day 10. In the 1.0 mg/kg/day group there was no beneficial effect of ORG2766, although a tendency towards a division between a subgroup resembling control animals and a subgroup with severe cisplatin effects was noted in the co-treated group. In the 1.5 mg/kg/day co-treated group three animals showed compound action potential (CAP) amplitudes close to those of the controls at all frequencies except the very highest (12 and 16 kHz), the remaining three had CAP amplitudes comparable to those of animals in the cisplatin alone group. The effect of ORG2766 on the latter group of six animals taken together was statistically significant. The dichotomy in the results for the 1.5 mg/kg/day group co-treated with ORG2766 suggests that ORG2766 may have a protective effect against cisplatin ototoxicity which, however, depends on a factor currently unknown.

Nonsyndromic hearing impairment is associated with a mutation in DFNA5.

Nonsyndromic hearing impairment is one of the most heterogeneous hereditary conditions, with more than 40 loci mapped on the human genome, however, only a limited number of genes implicated in hearing loss have been identified. We previously reported linkage to chromosome 7p15 for autosomal dominant hearing impairment segregating in an extended Dutch family (DFNA5). Here, we report a further refinement of the DFNA5 candidate region and the isolation of a gene from this region that is expressed in the cochlea. In intron 7 of this gene, we identified an insertion/deletion mutation that does not affect intron-exon boundaries, but deletes five G-triplets at the 3' end of the intron. The mutation co-segregated with deafness in the family and causes skipping of exon 8, resulting in premature termination of the open reading frame. As no physiological function could be assigned, the gene was designated DFNA5.

A functional anatomic study of the relationship of the nasal cartilages and muscles to the nasal valve area.

The functioning of the nasal valve area is largely determined by the stability and the mobility of the lateral nasal wall. To gain insight into the kinematics of the lateral nasal wall, we studied the functional anatomy of the nasal muscles and the intercartilaginous and osseous-cartilaginous junctions. We performed gross and microscopic nasal dissection and serial sectioning in 15 human cadaveric noses. In addition, two noses were used for three-dimensional reconstruction of the nasal cartilages. We conclude that the lateral nasal wall can be seen as made up of three parts. At the level of the osseous-cartilaginous chain of bone, lateral nasal cartilage, and lateral crus, the lateral nasal wall is relatively stable, limited mobility being allowed by translation and rotation in the intercartilaginous joint and a coupled distortion of the cartilages. At the level of the hinge area the lateral nasal wall is supported by one or more accessory cartilages, embedded in soft tissue, and therefore much more compliant. The alar part of the nasalis muscle, which originates from the maxilla and inserts on these cartilages, may dilate the valve area by drawing this hinge area laterally. The third and most compliant part of the lateral nasal wall is the part that is not supported by cartilage, the ala. The dilatator naris muscle largely occupies the ala and is attached to the lateral crus; it opens the vestibule and nostril. The third nasal muscle that influences the lateral nasal wall is the transverse part of the nasalis muscle. It overlies the nose but is not attached to it. This muscle stabilizes the lateral nasal wall, in particular, the lateral nasal cartilage, the intercartilaginous junction, and the hinge area, by moving the nasal skin.

Ciliary beat frequency of human sphenoid sinus mucosa after cryopreservation.

In vitro studies of human ciliary activity require relatively large quantities of specimens of healthy ciliated epithelium. For this reason we investigated whether cryopreserved healthy mucosa taken from the sphenoid sinus during pituitary surgery would meet the demands of this type of study. The sinus mucosa from ten patients was immersed in two different cryopreservatives. One solution contained 10% dimethylsulfoxide (DMSO) as cryoprotector. The other contained glycerol as a part of human sperm preservation medium (HSPM). The ciliary beat frequency (CBF) was measured sequentially by a photoelectrical method: when specimens were fresh and then at intervals of 1 week, 1 month and 3 months after cryopreservation in liquid nitrogen and thawing. Mean CBF values recorded after thawing did not differ significantly from the values measured before cryopreservation. Prior to cryopreservation and after thawing, CBF did not change during a period of 4 h. Epithelia preserved in DMSO demonstrated that the low mean CBF (5.4 Hz) found was caused by a reversible ciliostatic effect of the medium. After thawing and rinsing with a neutral medium, CBF showed normal values. We conclude that sphenoid sinus mucosa is an appropriate source of ciliated mucosa for in vitro experiments. Since non-pathological ciliated epithelium can be maintained in a "mucosa bank," our finding makes further studies of CBF of normal human respiratory epithelium in vitro a realistic goal.

Induction of endolymphatic hydrops in the guinea pig by perisaccular deposition of sepharose beads carrying and not carrying immune complexes.

We tried to induce endolymphatic hydrops in guinea pig cochleas by unilateral, perisaccular deposition of sepharose beads carrying immune complexes. Controls consisted of the deposition of sepharose beads without immune complexes and the contralateral, untreated ear. The effects of the treatment were studied by light microscopy and electrophysiological recordings of the gross cochlear potentials 1, 2, and 6 weeks after treatment. Each condition included six animals. Analysis of variance of the morphometric data concerning the ears treated with deposition of the beads showed a statistically significant difference (P = 0.04) between the degree of hydrops found for the beads with immune complexes and for those without. The difference between the treated ears and the contralateral untreated ears was significant (P = 0.01) for the beads with immune complexes and not significant (P = 0.8) for those without immune complexes while there was no significant effect of post-treatment time interval. Analysis of variance of the electrophysiological data, collected in response to tone bursts at the apex of the cochlea, showed no significant differences between the results for the beads with and without immune complexes. Therefore these results were pooled. One week after treatment the pooled results for the compound action potential showed a small decrease in amplitude, just significant at 2 kHz, but not at 4 and 8 kHz. This decrease disappeared completely after 6 weeks. The pooled results for the negative summating potential (SP) showed a significant increase in magnitude at all frequencies decreasing with post-treatment interval. The cochlear microphonics did not demonstrate any change in amplitude after treatment. The results indicate that deposition of sepharose beads with immune complexes induces endolymphatic hydrops. Also, deposition of the sepharose beads itself may have induced hydrops together with enhancement of the SP. SP enhancement may be related to the development of endolymphatic hydrops rather than to the presence of hydrops as such. This may be based on pressure build-up while hydrops develops.

Cisplatin-induced ototoxicity; electrophysiological evidence of spontaneous recovery in the albino guinea pig.

For 8 days albino guinea pigs (n = 48) were treated with cisplatin (cis-diamminedichloroplatinum(II), 1.5 mg/kg body weight/day). Compound action potentials (CAP), cochlear microphonics (CM) and summating potentials (SP) were recorded from the apical surface of the cochlea in response to tone bursts ranging in frequency from 0.5 to 16 kHz. The recordings were collected in different groups of animals, 1 day, 1 week, 2, 4, 8 and 16 weeks after cisplatin treatment, respectively. One day after the 8-day treatment we found frequency-dependent loss in the amplitudes of the three cochlear potentials, with the larger losses occurring at the higher frequencies. In terms of threshold shift the losses were larger for the CAP than for the hair cell-related potentials SP and CM. A salient improvement in both CAP and CM amplitude occurred over the next 8 weeks. Also, the SP showed improvement. These results indicate that guinea pig cochlear transduction recovers spontaneously after cisplatin injury. Recovery of the hair cell-related potentials suggests that recovery occurs already at the hair cell level. The question whether this recovery originates with the formation of new hair cells or with repair of damaged hair cells should be answered on the basis of subsequent morphological investigations.

Physical mapping of the HOXA1 gene and the hnRPA2B1 gene in a YAC contig from human chromosome 7p14-p15.

A cluster of homeobox-containing genes (HOXA) and a heterogeneous nuclear ribonucleoprotein (hnRPA2B1) have both previously been assigned to chromosome 7p15 by in situ hybridization. In this report, we constructed a YAC contig from chromosome 7p14-p15, between markers D7S2496 and D7S1838, and determined the position of the HOXA1 gene and the hnRPA2B1 gene in this YAC contig.