Confounding Effect in Clinical Research of Otolaryngology and Its Control.

Confounding effect is a critical issue in clinical research of otolaryngology because it can distort the research's conclusion. In this review, we introduce the definition of confounding effect, the methods of verifying and controlling the effect. Confounding effect can be prevented by research's design, and adjusted by data analysis. Clinicians would be aware and cautious about confounding effect in their research. They would be able to set up a research's design in which appropriate methods have been applied to prevent this effect.They would know how to adjust confounding effect after data collection. It is important to remember that sometimes it is impossible to eliminate confounding effect completely, and statistical method is not a master key. Solid research knowledge and critical thinking of our brain are the most important in controlling confounding effect.

Genetic Effects on Sensorineural Hearing Loss and Evidence-based Treatment for Sensorineural Hearing Loss.

In this article, the mechanism of inheritance behind inherited hearing loss and genetic susceptibility in noise-induced hearing loss are reviewed. Conventional treatments for sensorineural hearing loss (SNHL), i.e. hearing aid and cochlear implant, are effective for some cases, but not without limitations. For example, they provide little benefit for patients of profound SNHL or neural hearing loss, especially when the hearing loss is in poor dynamic range and with low frequency resolution. We emphasize the most recent evidence-based treatment in this field, which includes gene therapy and allotransplantation of stem cells. Their promising results have shown that they might be options of treatment for profound SNHL and neural hearing loss. Although some treatments are still at the experimental stage, it is helpful to be aware of the novel therapies and endeavour to explore the feasibility of their clinical application.

Clinical observation of soft palate-pharyngoplasty in the treatment of obstructive sleep apnea hypopnea syndrome in children.

BACKGROUND: Childhood obstructive sleep apnea hypopnea syndrome (OSAHS) is a common clinical disease that can cause serious complications if not treated in time. The preferred treatment for OSAHS in children is surgery. AIM: To observe the effects of soft palate-pharyngoplasty on postoperative outcome, pharyngeal formation, and possible complications. METHODS: A total of 150 children with snoring, hernia, and mouth breathing were selected. A polysomnography test was performed to confirm the diagnosis of OSAHS. The children were randomly divided into experimental and control groups. The experimental group underwent adenoidectomy, tonsillectomy, and soft palate-pharyngoplasty. The control group underwent adenoidectomy and tonsillectomy. The t-test and chi-square test were used to compare conditions such as postoperative fever, postoperative hemorrhage, and pharyngeal reflux. Postoperative efficacy and complications were interrogated and observed in the form of outpatient follow-up and telephone follow-up at 6 mo and 1 year after surgery. The curative effects were divided into two groups: Cure (snoring, snoring symptoms disappeared) and non-cure. RESULTS: The effective rate of the experimental group was significantly higher than that of the control group, but the difference was not statistically significant (P > 0.05). The incidence of postoperative bleeding was lower in the experimental group. There was no postoperative pharyngeal reflux in either group. In the experimental group, the incidence of hyperthermia (body temperature exceeded 38.5 °C) was lower than that in the control group. The difference in postoperative swallowing pain scores between the experimental and control groups was significant. CONCLUSION: Soft palate-pharyngoplasty can more effectively enlarge the anteroposterior diameter and transverse diameter of the isthmus faucium. Compared with surgery alone, it can better treat OSAHS in children, improve the curative effect, reduce the risk of perioperative bleeding, close the surgical cavity, reduce the risk of postoperative infection, reduce the proportion of postoperative fever, and accelerate healing. Although this process takes more time, it is simple, safe, and effective.

Tauroursodeoxycholic acid attenuates endoplasmic reticulum stress and protects the liver from chronic intermittent hypoxia induced injury.

Obstructive sleep apnea that characterized by chronic intermittent hypoxia (CIH) has been reported to associate with chronic liver injury. Tauroursodeoxycholic acid (TUDCA) exerts liver-protective effects in various liver diseases. The purpose of this study was to test the hypothesis that TUDCA could protect liver against CIH injury. C57BL/6 mice were subjected to intermittent hypoxia for eight weeks and applied with TUDCA by intraperitoneal injection. The effect of TUDCA on liver histological changes, liver function, oxidative stress, inflammatory response, hepatocyte apoptosis and endoplasmic reticulum (ER) stress were investigated. The results showed that administration of TUDCA attenuated liver pathological changes, reduced serum alanine aminotransferase and aspartate aminotransferase level, suppressed reactive oxygen species activity, decreased tumor necrosis factor-α and interleukin-1ß level and inhibited hepatocyte apoptosis induced by CIH. TUDCA also inhibited CIH-induced ER stress in liver as evidenced by decreased expression of ER chaperone 78 kDa glucose-related protein, unfolded protein response transducers and ER proapoptotic proteins. Altogether, the present study described a liver-protective effect of TUDCA in CIH mice model, and this effect seems at least partly through the inhibition of ER stress.

[Pathologic changes of the palatopharyngeal muscles in patients with obstructive sleep apnea hypopnea syndrome of different degrees].

OBJECTIVE: To study the pathologic changes of the palatopharyngeal muscles with transmission electronmicroscopy (TEM) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS), the role of the above muscle in OSAHS pathogenesis was discussed. METHODS: Thirty-eight palatopharyngeal muscle from OSAHS patients receiving uvulopalatopharyngoplasty (UPPP) were collected in in-patient department of Chinese Medical University and five palatal tumor patients receiving resection without snoring were chosen as the control. The palatopharyngeal muscle fiber and the feature of changes in mitochondrial morphology were observed by TEM. RESULTS: The pathological changes were not observed in the normal control group. The muscle fibers were regularly arranged, and the mitochondrial between muscles were normal. The palatopharyngeal myofibrillar in mild OSAHS group was regularly arranged. The Z lines were straight, and most mitochondria structure were normal. In the moderate group, the myofibrillar was disorganized, and the Z lines were shortened or distorted. The myofibrillar in severe group was disorganized, similar to point-like or flake, and the Z lines and the structures of sarcomeres were disappeared. And organelle were disintegrated and mitochondria were disappeared similar to flocculent. There existed obvious fatty infiltration in the palatopharyngeal muscle. In the control, mild, moderate and severe group, pharyngeal muscle fiber disarrangement of the occurrence rate was 0, 2/10, 8/13, 14/15, the occurrence rate of mitochondrial degeneration was 0, 2/10, 8/13, 14/15, increased with the severity of the ultrastructural changes in the trend of increasing incidence. CONCLUSIONS: The degree of OSAHS is correlated with the pathological changes of palatopharyngeal muscles. Incidence of myopathy is an important part of OSAHS secondary to chronic intermittent hypoxia in OSAHS and other pathological lesions, but also an important reason for increasing pharyngeal collapse.

[Effective evaluation of multiple level surgery in obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To investigate the therapeutic effects of multiple level surgery in treating obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: One hundred ninety two patients with OSAHS diagnosed by polysomnography were treated through uvulopalatopharyngoplasty (UPPP). Thirty patients were combined with sub-mucous resection of the nasal septum. Forty four patients received sub-mucous resection of the nasal septum and partial inferior turbinectomy. Two patients received sub-mucous resection of the nasal septum and partial resection of the tongue base. Two patients received genioglossus advancement and partial resection of the tongue base. Three patients received partial resection of the tongue base. In addition, the patients with the nasal disease and/or the lingual fat, AHI > 40 times/h, LSaO(2) < 0.64 and/or BMI > 30 kg/m(2) received tracheotomy before general anaesthesia. RESULTS: One hundred ninety two patients were treated through UPPP. One hundred ninety one patients were successful, one patient died of pneumothorax and cardiac arrest during the incision of the trachea. All patients were followed-up for 6-37 months, among them, 132 patients showed therapeutic effect, with the effective rate as 68.7%. Fifty five patients were cured (AHI < 5 times/h); 39 patients had significant effect (AHI < 20 times/h and decreased > or = 50%); 38 patients were effective (AHI decreased > or = 50%). However, 60 patients did not have any therapeutic effect, with the ineffective rate as 31.3%. Fifty four patients had palatopharyngeal and nasal cavity emphasis, 24 patients had palatopharyngeal and oropharyngeal emphasis, 96 patients had palatopharyngeal and nasal cavity and oropharyngeal emphasis. Some patients were treated with UPPP, which made effective rate as 15 (68.2%), 12 (63.2%), 29 (55.8%). The others were treated with multiple level operations, which made effective rate as 25 (78.1%), 5 (5/5), 33 (75.0%). The effective rate was 60.2% (56/93) by simple UPPP and it was 77.8% (63/81) by multiple level treatment in patients with multiple level obstruction. There was statistical significance between them (chi(2) = 6.2, P = 0.01). CONCLUSIONS: The effective rate was improved through multiple level operations in OSAHS patients. The serious complications could be prevented through tracheotomy before general anaesthesia in patients with severe OSAHS who needed multiple level surgery.

[Contralateral cervical lymph node metastasis in piriform sinus carcinoma].

OBJECTIVE: To evaluate relative factors affecting contralateral cervical lymph node metastasis in piriform sinus carcinoma. METHODS: Ninety-six cases of piriform sinus carcinoma with no preoperative treatments were selected. The contralateral cervical lymph node metastasis and relative factors were analyzed during operation or postoperative follow-up. The contralateral cervical metastasis was defined as followed: 1 contralateral cervical metastasis was confirmed pathologically after bilateral neck dissection (pN2c) or 2 contralateral cervical metastasis was found firstly during postoperative follow-up and the recurrence of primary lesion was excluded. RESULTS: The incidence of contralateral cervical metastasis was 32% (31/96). According to the T stage, the incidence of contralateral cervical metastasis was T1: 0% ,T2: 18%, T3: 37%, T4: 32% and to the N stage N0: 12%, N1: 13%, N2a: 17%, N2b: 39%, N2c: 100%, and N3: 75%. For primary lesions beyond midline the incidence of contralateral cervical metastasis was 52% but for those remaining on ipsilateral side it was 18%. CONCLUSIONS: Contralateral cervical lymph node showed higher metastatic incidence with higher T and N stage. When the primary lesions invaded beyond midline, the contralateral cervical metastasis increased greatly and neck dissection should be selected positively.

[Clinical observation and histological research of vocal cord's reformation after laser cordectomy].

OBJECTIVE: Explore the reformation of new vocal cord after laser cordectomy and the histological change of new vocal cord by animal experiment. METHODS: The reforming course of new vocal cord was observed by follow-up. 4 dogs underwent bilateral cordectomy (type II operation) and their larynx were analyzed anatomically and histologically eight months later. 100 cases who underwent KTP laser cordectomy were divided into 3 types according to the range and depth of the excision. RESULTS: All the dogs had reformation of vocal cords eight months later. On the surface of the reformed vocal cord, no mucous cell but squamous cells was found. Newborn ligament-like connective tissues and loose muscle fibers were found under membrane. Complete reconstruction of larynx was found in 16 cases of type I (16/16) and 54 of type II 86% (54/63). But in type III no new vocal cord was found. CONCLUSION: Formation of the new vocal cord is the result of hypertrophy of the remained vocal cord muscle, influenced by depth of the excised vocal cord using laser. The histological construction is nearly normal cord. Whether or not the laser radiation stimulate the tissue hypertrophy is need more research.