VENTILATION TUBE DURATION VERSUS SITE OF PLACEMENT

Background : The duration a ventilation tube remains in the tympanic membrane is thought to be related to the design of the ventilating tube, and to the site of placement of the ventilation tube into the tympanic membrane. Theoretically a ventilating tube placed superiorly should remain longer than one placed inferiorly. Methods : A prospective study was designed to test the hypothesis that ventilation tubes placed into the antero-superior quadrant of the tympanic membrane remained longer than those placed into the antero-inferior quadrant. Results : In 106 children no statistically significant difference in duration was identified using three designs of ventilation tube. Conclusions : Ventilating tubes placed antero-superiorly into the tympanic membrane do not have a longer duration than those placed antero-inferiorly.     

Ventilation tubes and persisting tympanic membrane perforations.

Surgical management of otitis media with effusion and recurrent acute otitis media includes myringotomy and the use of ventilation tubes. Since this procedure was reintroduced by Armstrong in 1954, it has become one of the most commonly performed operations in otolaryngology. In most series perforation of the tympanic membrane in some patients has been reported after spontaneous extrusion or removal of the tympanostomy tubes. We present a retrospective review designed to examine the incidence of persisting perforations of the tympanic membrane in our series of 2604 operated ears. The study also identifies and analyzes the variables and the contributing risk factors. Perforations occurred in 3.06% of the ears: with a greater incidence in children younger than 5 years, when the indication was recurrent purulent otitis media, with the use of long-term Goode T tubes, in cases with repeated insertions of ventilation tubes, and in cases in which postoperative otorrhea was frequent.     

The extrusion rate of grommets

A prospective study was performed to determine the factors influencing the extrusion rate of tympanostomy tubes. Nine hundred thirty-nine tubes were inserted in 589 patients and the extrusion of these tubes was reviewed up to a period of 27 months. The eight tubes used in the survey were the Shepard, Exmoor, Bobbin, Armstrong, Paparella, Shah, Arrow, and collar button. These tubes were inserted in strict rotation, the operator using the designated tube. The position, type of incision, presence of fluid, quality of tympanic membrane, and degree of difficulty of insertion were all recorded at operation. The sex, age, side of operation, and any simultaneous operative procedures were also recorded. The patients were reviewed the day after operation and then every 3 months thereafter until the tube was extruded. A definite pattern was identified for the extrusion of each type of tube. At one end of the spectrum, Exmoor and Shepard tubes were, for the most part, extruded between 6 and 9 months after insertion, while at the other end, most of the collar button tubes were still functioning at 18 months. The design of the tube was the only factor found to be a significant determinant of the extrusion of the tube, although the experience of the surgeon affected the extrusion rate of the Arrow tube. The different dimensions of the Exmoor and collar button tubes are examined and compared.     

Six Sigma tympanostomy tube insertion: achieving the highest safety levels during residency training

OBJECTIVE: To evaluate a protocol designed to avoid complications during tympanostomy tube insertion by residents. DESIGN: Ten-year consecutive cases series by a single surgeon supervising residents. SETTING: Tertiary children's hospital. PATIENTS: Children 6 weeks to 21 years. INTERVENTION: Residents followed a defined protocol for tube insertion. A resident operated until the tube was placed or he/she committed one major or two minor errors. MAIN OUTCOME MEASURES: Incidence of 1) major complications: profound sensorineural hearing loss (SNHL), injury to major vascular structures, or disruption of the ossicular chain; and 2) minor complications: tube loss into the middle ear, tympanic membrane tears, or tube occlusion by blood clot. RESULTS: There were no major complications in 10,000 tube insertions. Two children had unilateral profound SNHL; both were found to have Mondini malformations. Five tubes were recovered from the middle ear. Eight tympanic membrane tears healed with gelatin patches. Three tubes were occluded by blood clots. CONCLUSION: By following a defined protocol, major complications of a common operation can be reduced to the five-sigma level and minor complications minimized.     

External and middle ear effects on infant hearing screening test results.

This study investigated the relationship between external and middle ear factors and hearing screening results by automated auditory brain stem response (ABR) and transient-evoked otoacoustic emissions (EOAEs). The ears of 200 healthy newborns aged 5 to 48 hours underwent screening by ABR and EOAE, followed by otoscopic examination. The pass rates for ABR and EOAE were 91% and 58.5%, respectively. On otoscopic examination, 28% (112/400) ears had occluding vernix obscuring the view of the tympanic membrane. Cleaning of vernix was successfully performed in all but 2 ears that had occluding vernix. Cleaning of vernix significantly increased the pass rates of all 400 ears for ABR and EOAE to 96% and 69%. Decreased tympanic membrane mobility was found in 22.7% (90/396) of ears that were evaluated otoscopically. Decreased tympanic membrane mobility had a significant effect on EOAE screening; only 33.4% of ears passed EOAE testing. Decreased tympanic membrane mobility did not significantly affect pass rates for ABR screening; 95% of these ears passed the automated ABR screen. Implications for newborn hearing screening are discussed.     

Laser-assisted tympanostomy in pediatric patients with serous otitis media.

OBJECTIVES: To evaluate prognostic factors related with cure rate, in pediatric patients with serous otitis media treated with laser-assisted tympanostomy without ventilation tubes, in a single institution. PATIENTS AND METHOD: The procedure was performed on 124 ears in 88 individuals, from 3 to 14 years old. External auditory canal anatomy, type of anesthesia, tympanic membrane and middle ear fluid characteristics, myringotomy size, and laser parameters, in relation to cure rate, were accordingly studied. RESULTS: The overall cure rate by ear at the end of the 2-month follow-up period was 54.83%, whereas 45.17% still suffered from otitis media. Multivariate statistical analysis demonstrated that the presence of a thick tympanic membrane is significantly correlated with pure outcome in children with serous otitis media, when laser-assisted tympanostomy without ventilation tubes is performed favoring a worse cure rate (P < 0.023). Other parameters did not statistically correlate with the outcome. A 41% parental dissatisfaction rate was noticed. CONCLUSION: This study addresses selection bias for children with serous otitis media, candidates for laser-assisted tympanostomy. These are related to the duration of serous otitis media, the condition of middle ear mucosa, the thickness of the tympanic membrane, the type of anesthesia, and the cost of laser apparatus. There is likely to be a causal relationship between outcome and tympanic membrane appearance in children undergoing laser-assisted tympanostomy.     

Alternative indications for laser-assisted tympanic membrane fenestration

BACKGROUND AND OBJECTIVE: To assess the utility of the CO(2) Flashscanner laser for treatment of selected middle ear diseases other than otitis media with effusion (OME) and acute otitis media (AOM). STUDY DESIGN/MATERIALS AND METHODS: A retrospective review of the records of 144 patients treated with the OtoLAM((R)) device, a Flashscanner laser, between July 1, 1998, and February 29, 2000. Patients treated for AOM or OME were excluded. RESULTS: Data are presented on 11 patients (17 ears). Four indications were identified: Elimination of middle ear fluid before auditory brainstem response with or without otoacoustic emission testing (ABR +/- OAE), barotrauma, eustachian tube obstruction, tympanocentesis when a culture of middle ear fluid was deemed necessary. All tympanic membranes (TM) healed. CONCLUSIONS: Fenestration of the TM can be accomplished for both diagnostic and therapeutic purposes. Laser assisted tympanic membrane fenestration seems to be effective in the management of middle ear fluid before ABR +/- OAE, barotrauma, eustachian tube dysfunction, and for tympanocentesis.     

Neonatal hearing screening with otoscopy, auditory brain stem response, and otoacoustic emissions

A study was performed to investigate the relationship between external and middle ear factors and hearing screening results by auditory brain stem response (ABR) and transient evoked otoacoustic emissions (EOAEs). The ears of 200 well newborns aged 5 hours to 48 hours underwent screening by ABR and EOAEs, followed by otoscopic examination. The pass rates for ABR and EOAE screening were 88.5% and 79%, respectively. On otoscopic examination, 13% (53 of 400) ears had occluding vernix obscuring the view of the tympanic membrane. Cleaning of vernix was attempted in ears that failed ABR or EOAE screening. Seventeen ears that failed ABR were cleaned, and 12 (71%) of them passed repeat ABR. Thirty-three ears that failed EOAE screening were cleaned, and 22 (67%) of them passed repeat emissions testing. Cleaning vernix increased the pass rates for ABR and EOAE screening to 91.5% and 84%, respectively. Decreased tympanic membrane mobility was found in 9% of ears that could be evaluated otoscopically. Increased failure rates for both ABR and EOAE screening were found in infant ears with decreased tympanic membrane mobility, but significance testing could not be performed because of inadequate sample size. Prevalence of occluding external canal vernix and middle ear effusion as a function of increasing infant age were studied. Implications for newborn hearing screening are discussed. (Otolaryngol Head Neck Surg 1997;116:597-603.)     

Conductive hearing loss associated with pressure equalization tubes.

Pressure equalization (PE) tube placement traditionally has been used to lessen conductive hearing loss with chronic middle ear effusion. It is assumed that the small diameter of the tube should not interfere with the conduction of sound. In this article we present 5 patients in whom placement of a PE tube resulted in significantly worse conductive hearing. Occlusion of the PE tube with cigarette paper or Gelfoam improved hearing, as documented with audiometry. The average conductive hearing losses attributable to the ventilation tube for this series of patients were 22, 17, 15, 13, 4, and 10 dB at the frequencies of 250, 500, 1000, 2000, 4000, and 8000 Hz, respectively. This amount of change attributable to PE tubes in this small selection of patients is much greater than would be commonly appreciated. We conclude that the opening in the tympanic membrane provided by PE tubes can potentially result in a significant conductive hearing loss. Discussion includes those conditions in which reduced hearing may be more likely to occur.     

A new absorbable pressure-equalizing tube.

OBJECTIVE: We investigated pressure-equalizing (PE) tubes made of biodegradable, absorbable material in an animal model. METHODS: PE tubes, made of poly-bis(ethylanate)phosphazene (PBE) were inserted in 55 ears of 28 Hartley guinea pigs, with survival times of 10, 30, and 60 days after tube insertion. In vivo reactions between the PBE-PE tube and the tympanic membrane (TM) were studied. Tubes, TMs, and middle ears were examined by scanning electron microscopy and light microscopy. RESULTS: There was neither infection nor an inflammatory reaction to the tube within the middle ear in any animal. At 30 days, 53% of the tubes had disintegrated. At 60 days, tubes were still functioning in the 25% of ears. CONCLUSION: More research must be performed before these new PBE PE tubes can be considered for clinical use. Nonetheless, these tubes are promising. The disintegration rate can be controlled by varying the formulation of the polymer, so treatment can be adjusted to the needs of each patient.     

Core temperature measurements through a new airway device, perilaryngeal airway (CobraPLA)

STUDY OBJECTIVE: The aim of this study was to test the hypothesis that the intraoperative pharyngeal temperatures obtained on the perilaryngeal airway (PLA), a novel airway device with a larger pharyngeal cuff (when inflated) than the laryngeal mask airway, are similar to tympanic membrane core temperatures. DESIGN: This study is a prospective, simultaneous device comparison. SETTING: This study was set at a university hospital. PATIENTS: The study patients included 14 adults with American Society of Anesthesiologists physical statuses I and II, scheduled for minor gynecological or orthopedic surgery. INTERVENTIONS: A PLA was inserted into the pharynx after induction of general anesthesia. Thermocouples were positioned at 3 sites on the PLA: (1) posterior portion of the head of the airway (tip), (2) midposterior portion of the cuff, and (3) left and right lateral-posterior portions of the cuff. Tympanic membrane thermocouples were inserted. MEASUREMENTS: Temperature readings from the airway and the tympanic membrane thermocouples were recorded every 15 minutes throughout surgery. MAIN RESULTS: Temperatures recorded from the lateral-posterior cuff were found to be virtually identical to tympanic membrane temperatures, with 97% of the values differing by less than 0.5 degrees C. Readings from the other 2 sites on the cuff differed considerably more from tympanic membrane values. CONCLUSIONS: These data suggest that the PLA can be adapted to monitor core temperature reliably.     

A biointegrated hydroxylapatite ventilation tube for definitive treatment of chronic eustachian tube obstruction.

A dense hydroxylapatite ventilation tube has been designed for the purpose of providing prolonged ventilation of the middle ear. The tube is placed beneath the fibrous annulus of the eardrum, into a groove within the bony annulus and canal. The device takes advantage of the documented biocompatibility of hydroxylapatite to achieve biointegration with the soft tissues of the fibrous annulus, drum, and canal skin, as well as the bone of the deep ear canal. The tube does not appear to cause a foreign body reaction, and does not seem to extrude over time. The device is proposed for patients with unresolving eustachian tube obstruction who require a permanent tympanic stoma for normal middle ear function.     

Preapplication of mitomycin C for enhanced patency of myringotomy.

OBJECTIVES: Ventilation tubes are the mainstay of surgical treatment for eustachian tube dysfunction and have been used successfully for many years. Certain disadvantages of ventilation tubes, however, have prompted research into alternative techniques including laser myringotomy. We investigated the use of KTP laser myringotomy in conjunction with topical mitomycin C to delay healing and prolong the patency of the myringotomy. METHODS: Twenty myringotomies were created in 10 Sprague-Dawley rats. A solution of mitomycin C was applied to the intact tympanic membrane for 15 minutes. The solution was then suctioned free, and a myringotomy was created with a KTP laser. Fifty-three rats with saline application serving as controls from a previous study were used to allow statistical assessment. RESULTS: The myringotomies remained open for a median of 9.5 weeks. Control myringotomies, which received saline solution instead of mitomycin C, healed within a median of 1.5 weeks. The difference was statistically significant at P < 0.0001. No complications were noted. CONCLUSION: Topically administered mitomycin C before laser myringotomy is effective in prolonging the patency of laser myringotomies in rats. The patency rate is similar to that achieved in experiments in which topical mitomycin C is placed into the myringotomy site created by the laser.     

Ⅰ型胶原凝胶包埋脂肪干细胞复合PLGA-β-TCP支架修复兔自体桡骨缺损

目的 采用Ⅰ型胶原凝胶悬浮包埋兔脂肪干细胞并复合PLGA-β-TCP支架修复自体桡骨缺损。方法 使用Ⅰ型胶原凝胶悬浮兔脂肪干细胞并与PLGA-β-TCP复合构建脂肪干细胞-Ⅰ型胶原凝胶/PLGA-β-TCP复合体(ASCs-COL/PLGA-β-TCP)(A组),同时设立单纯细胞/PLGA-β-TCP材料复合体(ASCs/PLGA-β-TCP)(B组)、单纯Ⅰ型胶原凝胶/PLGA-β-TCP复合体(COL/PLGA-β-TCP)(C组)、单纯PLGA-β-TCP支架材料(D组)以及空白缺损(E组)作为对照,体外成骨诱导培养2周后植入桡骨1.5cm缺损部位。30只兔(60侧)采用两因素随机区组设计每只兔两侧骨缺损植入组别。分别于术后8、16、24周处死兔,取材,进行相关分析。结果 术后8周,大体观察、放射学、组织学检测示A组桡骨断端连续性基本恢复。术后16周,A组骨断端连续性完全恢复,髓腔未通。术后24周,A组髓腔再通,改建塑形趋于完成,材料基本降解。自术后16～24周,A组残存材料比例低于其他3组(P＜0.05,n=4);与A组比较,在整个观察周期内,B、C、D组均无明显成骨现象,E组保持骨缺损状态(P ＜0.05,n=4)。结论 通过应用Ⅰ型胶原凝胶悬浮包埋脂肪干细胞进而与PLGA-3-TCP多孔支架材料复合构建新型仿生骨组织工程复合体,可修复兔桡骨1.5 cm缺损。     

Middle ear semipermeable membrane tubes for prolonged retention

Our 1981 prospective study confirmed the success of semipermeable membrane tubes in ventilation of middle ears, while protecting them from moisture when the patients bathed or swam. That study employed modern membrane tubes, with membrane-pore size 2.5 to 5 times greater than tubes used in early studies with less favorable outcomes. Currently, 21 patients with effusion had placement of a Donaldson design (Xomed, Inc., Jacksonville, Fla.) membrane tube in one ear and the new T-grommet membrane tube in the second ear. The T-grommet membrane tube is found to outlast the Donaldson design tube significantly. We recommend Donaldson membrane tubes for patients having tubes placed for the first time. For subsequent procedures, we employ T-grommet membrane tubes. We also use the T-grommet membrane tube for adults with chronic eustachian tube problems. Both tubes continue to show a low incidence of complications and draw highest praise from patients for their water-resistant capabilities.     

Tympanic membrane changes secondary to tympanostomy tube insertion in chinchillas

Tympanostomy tubes were inserted in 16 chinchillas to study the effect on tympanic membrane morphology. Tympanic membranes were examined with an operating microscope after 72 hours and at weekly intervals thereafter. Three ears developed postoperative otorrhea. Except for the ears with otorrhea, all tympanic membranes remained gray and translucent. Histologically, granulation tissue and polymorphonuclear leukocyte infiltration occurred around the tympanostomy tube by 7 days. With time this was replaced by a mature fibrous ring, which explained the tissue band observed otoscopically. In those tympanic membranes where the tympanostomy tube had extruded, healing occurred with an overly developed membrana propria. The middle ears of all experimental animals remained free of pathologic changes except for the three ears with otorrhea.     

Comparison of different operation techniques and suture materials in pyloric exclusion,in an animal model

PURPOSE: The aim of this study is to compare the results of different operating techniques and suture materials for pyloric exclusion procedures. METHODS: The study was conducted on a sample of 125 rats. Transgastric pyloric exclusions with gastrojejunostomy were performed on the first 50 rats, which were divided into two groups each of 25: a resorbable (polyglactin) suture material was used in the first group and a nonresorbable (silk) material was used in the second group. External pyloric exclusion with a gastrojejunostomy were performed in a subsequent group consisting of 50 rats, again divided into two subgroups of 25 each with an absorbable (polyglactin) suture material used in one and a nonabsorbable (silk) material used in the other. For the last 25 rats external pyloric exclusion with a gastrojejunostomy were performed and a nonresorbable (polypropylene) material was used. RESULTS: The ratio of pyloric reopening was higher in the transgastric group than the external exclusion group on the 14th day (P = 0.01). The external pyloric exclusion group with polypropylene suture material had the lowest ratio of pyloric reopening. CONCLUSION: The external pyloric exclusion technique with nonresorbable (preferably polypropylene) suture material was therefore found to provide a higher pyloric closure incidence on the 14th day, which is the necessary duration period for healing in duodenal injuries.     

Laser myringoplasty for tympanic membrane atelectasis

OBJECTIVE: To review our experience with laser myringoplasty using a potassium-titanyl-phosphate (KTP) laser for pars tensa atelectasis. STUDY DESIGN: Retrospective review. METHODS: A pulsed diode KTP laser (532 nm) was used to tighten the tympanic membrane after lysis of middle ear adhesions through a myringotomy. A tympanostomy tube was then placed. Operative reports and clinic notes were reviewed. RESULTS: We reviewed 34 procedures performed on 31 ears in 29 patients. The average time of follow-up was 10.5 months with a range of 1 to 30 months. Seventeen of 34 tubes (50%) extruded during the follow-up period. Eleven cases had follow-up with the tube extruded and TM intact. Two (18%) of those had progression of atelectasis. Two (6%) cases had operative perforations and both healed spontaneously. CONCLUSION: Laser myringoplasty using a KTP laser for pars tensa atelectasis appears to be beneficial in selected patients. Patients should be followed closely for early tube extrusion and recurrent disease.     

Comparative observation of protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure

Objective: To explore the protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure (BUP). Methods : The hearing thresholds of the guinea pigs were assessed with auditory brainstem responses ( ABR). The traumatic levels of tympanic membrane and ossicular chain were observed under stereo-microscope. The rate of outer hair cells (OHCs) loss was analyzed using a light microscope. The changes of guinea pigs protected with barrel and earplug were compared with those of the control group without any protection. Results: An important ABR threshold shift of the guinea pigs without any protection was detected from 8h to 14d after being exposed to BUP with a peak ranging from -64.5 kPa to -69.3 kPa (P<0.01). The rate of perforation of tympanic membrane reached 87.5 % and that of total OHCs loss was 19.46%±5.38% at 14d after exposure. The guinea pigs protected with barrel and earplug had lower ABR threshold and total OHCs loss rate compared with the animals without any protection (P<0.01). All of the tympanic membrane and ossicular chain of the protected animals maintained their integrities. Meanwhile, the guinea pigs protected with the barrel had lower ABR threshold and total OHCs loss rate than those with earplug (P<0.01). Conclusions: The earplug and barrel have protective effects against BUP-induced trauma on auditory organs of the guinea pigs and the protective effects of barrel are better than those of earplug.     

Hydrogen peroxide ototoxicity in unblocking ventilation tubes: a chinchilla pilot study.

OBJECTIVE: Some clinicians use hydrogen peroxide (H2O2) to clear the lumen of ventilation tubes that become blocked postoperatively. The ototoxicity associated with H2O2 has been controversial. STUDY DESIGN: We designed an experiment to test if H2O2 damages the cochlear hair cells using a Chinchilla laniger animal model. METHODS: Nine chinchillas (18 ears) were included in this study. Each animal was used as its own control. Following the insertion of ventilation tubes in both ears and baseline recordings of the auditory brain stem responses (ABR), we instilled 2 ml of 3 percent H2O2 into their right external auditory canals (experimental ears). H2O2 was left in the external auditory canal for a total of 5 minutes and then was drained. We instilled a normal saline control solution in their left ears (control ears) in a similar fashion. ABR recordings were performed 1 day after the last instillation of H2O2 and 5 days later. RESULTS: There was no statistically significant difference in the ABR thresholds of the experimental and control ears. CONCLUSION: H2O2 did not appear to cause ototoxicity in chinchilla ears with tympanostomy tubes exposed to H2O2 instillation using a standard clinical protocol.