Efficacy of Larynx Preservation Surgery and Multimodal Adjuvant Therapy for Hypopharyngeal Cancer: A Case Series Study.

Background: Larynx preservation surgery (LPS) combined with multimodal adjuvant therapy (MAT) is re-emerging as treatment option for hypopharyngeal cancer (HPC). This study aims to explore the survival and functional outcome of this combined approach. Methods: This is a retrospective cohort study. Selected patients with primary HPC treated by LPS and MAT at two large Beijing medical centers between 2005 and 2019 were included. In addition to LPS, patients received one or more of the following treatments: preoperative induction chemotherapy, postoperative intensity-modulated radiotherapy, chemotherapy, or targeted therapy. Results: In total, 64 patients were included (62 were men, and median age was 57.5 years). The disease in most patients was in stage III (28.1%) or IV (56.3%), or in stage T2 (34.4%) or T3 (45.3%), based on the TNM scale. Across all patients, the rate of overall survival (OS) was 60.7% at 3 yr and 47.3% at 5 yr. OS was significantly higher for patients with stage I or II disease than for those with stage III or IV disease (HR 8.64, 95% CI 3.69-20.2, log-rank P = .010). Decannulation was successful in 55 patients (85.9%), and swallowing function was satisfactory (stage 0-III, on Functional Outcome Swallowing Scale) for 50 (78.1%). Median Voice Handicap Index-10 score on voice performance was 19 (range 4-40), and median Functional Assessment of Cancer Therapy-General Questionnaire score for QoL was 75 (range 16-105). Conclusions: LPS and MAT can provide satisfactory oncologic control and good functional outcomes for selected patients with HPC, especially those with stage I or II disease.

Delayed oral feeding reduces pharyngocutaneous fistula formation after open surgical treatment of primary hypopharyngeal cancer: A case-control study.

OBJECTIVES: Pharyngocutaneous fistula (PCF) formation following open surgical treatment of hypopharyngeal cancer (HPC) is a common and troublesome complication. To date, the postoperative protocol of restarting oral intake is not clear, and vast discrepancies exist in the literature and among institutions. This study aimed to explore the impact of a postoperative protocol of restarting oral intake on PCF formation after open surgical treatment of primary HPC, and its impact on overall survival (OS) and swallowing function based on the functional outcome swallowing scale (FOSS). MATERIALS AND METHODS: This was a prospective observational study of 42 patients who received open surgical treatment for primary HPC at Beijing Friendship Hospital between April 2019 and August 2021. This cohort included two groups: patients who restarted oral intake on the 10th postoperative day (Group 1), and those who started on the 20th (Group 2). The Chi-square test and Fisher's exact chi-squared test were used for comparing qualitative data among the groups. RESULTS: Group 1 (n = 27) and Group 2 (n = 15) were comparable in clinical characteristics. PCF occurred in 7 (25.9%) patients in Group 1, while none occurred in Group 2 (P = 0.038). The 2-year OS of all 42 patients was 75.6%; 65.8% and 93.3% for Groups 1 and 2, respectively (P = 0.07). The swallowing function was satisfactory (FOSS Grades 0-III) for 19 (70.4%) patients in Group 1 and 15 (100%) patients in Group 2 (P = 0.035). Laryngeal preservation was achieved in 25 (59.5%) patients, while decannulation was successful in 22 (88.0%) patients. CONCLUSIONS: Delayed oral feeding significantly reduces PCF after open surgical treatment of primary HPC, and improves the swallowing function outcome without jeopardizing the OS.

Analysis of risk factors for lateral lymph node metastasis in papillary thyroid carcinoma: A retrospective cohort study.

Objective: To investigate the risk factors for lateral lymph node metastasis (LLNM) in papillary thyroid carcinoma (PTC). Methods: A retrospective analysis of 209 patients with PTC who underwent primary surgery at the Beijing Friendship Hospital affiliated with Capital Medical University from November 2014 to November 2018 was performed. The patients were divided into the LLNM group and the non-LLNM group. The clinical and pathological characteristics of the patients were analysed. The risk factors for LLNM were analysed by univariate and multivariate analyses. Results: The incidence of LLNM was 13.4% in PTC patients. Univariate analysis showed that the maximum diameter of the primary tumour > 2 cm (P < 0.001), bilateral primary tumour (P = 0.020), extrathyroidal extension (ETE) (P < 0.001), central lymph node metastasis (CLNM) (P < 0.001), and CLNM number ≥ 5 (P < 0.001) were significantly associated with LLNM. Multivariate logistic regression analysis showed that the maximum diameter of the primary tumour > 2 cm, ETE, and CLNM were independent risk factors for LLNM (OR values were 3.880, 5.202, and 4.474, respectively). There were 6 patients with skip lateral cervical lymph node metastasis, accounting for 21% of all LLNM patients. Conclusion: This study revealed several independent risk factors for predicting LLNM in PTC patients, such as the maximum diameter of the primary tumour > 2 cm, ETE and CLNM. Lateral neck dissection may be recommended in PTC patients with those risk factors. Paying attention to the occurrence of skip lateral cervical lymph node metastasis during the clinical diagnosis and treatment processes is necessary.

Intracapsular Enucleation of Cervical Sympathetic Chain Schwannoma.

OBJECTIVES: Schwannoma arising from cervical sympathetic chain (CSC) is a rare clinical entity. CSC is hard to preserve in CSC schwannoma (CSCS) surgeries, resulting in Horner's syndrome (HS) and first bite syndrome (FBS). This article aims to explore our experience in successful preservation of CSC in CSCS surgeries. METHODS: This is a retrospective review of CSCS cases treated at our tertiary medical institution between Apr 2018 and March 2022. Only cases with successful intraoperative preservation of CSC were included. RESULTS: In total, 3 cases were included. There were 2 male patients and 1 female patient. Their age was between 38 years old and 66 years old (average and median age was 52 and 51 years old, respectively). Presenting symptom was neck mass for all them, 2 of which were on the left side, while 1 was on the right. Intracapsular enucleation of the CSCS was attempted and achieved in all 3 cases. Hemorrhage from the inner surface of capsules was diffuse and heavy. Constant saline irrigation, suction, and bipolar coagulation were needed to achieve hemostasis. Postoperative HS presented between 4 hours and 14 hours after surgery for all 3 patients, which took 1 month to 3 months to recover, whereas FBS did not occur in any patient. Median duration of follow-up was 6 months. No recurrence was observed. CONCLUSIONS: Intracapsular enucleation should be attempted in CSCS surgeries, although hemorrhage might be diffuse and hard to control. When intracapsular enucleation was achieved, postoperative FBS can be avoided, while postoperative HS could occur, but its recovery was satisfactory.

Survival and swallowing function outcome impact factors analysis of surgery-oriented comprehensive treatment for hypopharyngeal cancer in a series of 122 patients.

OBJECTIVE: Under current standards of treating highly aggressive hypopharyngeal cancer (HPC), oncological control and functional outcome are still unsatisfactory worldwide. This study explored the surgery-oriented comprehensive treatment approach based on 15 years of practice. METHODS: A retrospective cohort of HPC patients treated by the senior author at Chinese PLA General Hospital between Nov 2005 and Aug 2012 and Capital Medical University Beijing Friendship Hospital between May 2014 and Nov 2019 was studied. Oncological control, swallowing function, and quality of life (QoL) were assessed. RESULTS: In total, 122 patients were included in this study, with 11 (9.0%) cases in the early stage and 111 (91.0%) cases in the advanced stage. Five-year overall survival (OS) and disease-free survival (DFS) were 40.0% and 36.1%, respectively. The swallowing outcome was satisfactory in 90 (73.8%) patients. Tracheostomy-free survival was achieved in 55 (45.1%) patients. Multivariate cox regression analysis showed that the size of the surgical defect, local-regional recurrence, and distant metastasis were independent impact factors for OS and DFS (P < .05). Multivariate analysis showed that the logistic regression coefficients (standard error) of pharyngo-cutaneous fistula and local-regional recurrence on swallowing function were 1.274 (.532) and 1.283 (.496), respectively (P < .05). In addition, the logistic regression coefficients (standard error) of the clinical stage, local-regional recurrence, decannulation, and feeding tube on QoL were -7.803 (3.593), -7.699 (3.151), 13.853 (3.494), and -20.243 (3.696), respectively (P < .05). CONCLUSIONS: Surgery-oriented comprehensive treatment can give rise to good swallowing function without jeopardizing oncological control. The size of the surgical defect, local-regional recurrence, and distant metastasis were independent factors impacting OS and DFS. Pharyngo-cutaneous fistula and local-regional recurrence were independent factors impacting swallowing function. Clinical stage, local-regional recurrence, decannulation, and feeding tube were independent factors impacting QoL.

Diagnosis and Management of Giant Esophageal Fibrovascular Polyp With Hypopharyngeal Pedicle.

Background: Fibrovascular polyps (FVPs) with hypopharyngeal pedicles (hFVPs) are the rare intraluminal benign tumours of the upper aerodigestive tract, and their accurate diagnosis and optimal management are challenging. Purpose: The present retrospective study attempted to explore the optimal diagnosis and treatment of hFVPs. Research Design: The clinical records of 2 patients with giant, irregularly shaped hFVPs, who underwent several failed surgical procedures after inaccurate diagnosis, were reviewed. Finally, the patients were correctly diagnosed and successfully treated at Capital Medical University Beijing Friendship Hospital in different years, 2018 and 2020. Results: Case 1 was of a 43-year-old woman with 2 months of progressive dysphagia. Gastroenterologists overlooked the origin of her FVP, and decided to sever its narrowest point in the oesophagus through endoscopy. However, upon unsuccessful removal of the mass, a gastrotomy procedure was performed to extract the mass 7 days later. Symptoms recurred 3 months after the treatment, and a fibreoptic laryngoscopy confirmed hFVP in the patient at our department. A transcervical approach was used to sever the hypopharyngeal pedicle, achieve haemostasis and remove the oesophageal tumour. No recurrence was detected during the 2-year follow-up period after the treatment. Case 2 was of a 32-year-old man with dysphagia who had previously undergone transthoracic and transcervical oesophagotomy procedures within a gap of 3 months for the removal of FVP causing dysphagia. The hypopharyngeal pedicle was not diagnosed in the patient. The symptoms of dysphagia recurred 4 years after the treatment, and a fibreoptic laryngoscope confirmed hFVP at our department. The tumour was removed successfully through the transcervical approach. No recurrence was detected during the 6-months follow-up after surgery. Conclusion: In conclusion, the transcervical approach is suitable for achieving haemostasis and removing giant, irregularly shaped hFVPs.

[Surgical treatment of carotid body tumor: a report of 36 cases].

OBJECTIVE: To study surgical methods and techniques to reduce complications in carotid body tumors (CBT). METHODS: A total of 36 patients with CBT treated by the same surgeon between 2004 and 2012 was reviewed. Clinical presentation, imaging, surgery techniques, postoperative complications and outcomes as well as follow-up evaluations were analyzed. RESULTS: Of 36 patients, 13 males and 23 females, with a median age of 42 years (range 9-61 years). Nineteen patients had a CBT on the left side, 14 on the right side and 3 on both sides. All patients (36 patients with 38 tumors) received surgical treatment. Twenty nine tumors were excised completely. Kudo clamp was used in 6 cases with solid firm tumors and potentially high risks of intracranial complications, with common carotid artery compression exercise before tumor excision. Blood loss in operation were less than 80 ml(n = 17), 100-550 ml(n = 18), 800 ml (n = 1), 1000 ml(n = 1) and 1500 ml(n = 1) respectively. There were more blood loss in cases used embolization (median of 200 ml) than in those without embolization (median of 60 ml) . Post-operative local nerve impairment occurred in 10 patients (26.3%) including persistence of preexisting deficits (n = 8) and newly developed deficits (n = 2). Twenty-seven patients were followed up for 10 month to 6 years with a mean period of 24 months and 9 patients lost of follow-up. One patient with malignant CBT survived with tumor and other 26 patients were alive with no recurrence. CONCLUSIONS: Surgery is the first choice of treatment for CBT. Soft CBT often can be excised completely with preservation of the internal carotid artery (ICA), whereas solid firm CBT encasing the ICA should be evaluated with DSA preoperatively to determine the presence of communicating branches of cerebral vessels, due to the high risk of major vessel compromise. Two-stage operation is often required, in which the ICA is gradually closed following ligation of the external carotid to establish collateral circulation, followed by excision of the tumor and IAC, so that serious intracranial complications can be avoided.

[Changes of gamma-amino butyric acid and electrophysiology inferior colliculus after noise exposure in guinea pig].

OBJECTIVE: To explore the changes of inferior collicular (IC) neurons after noise exposure cochlea injury in guinea pig to elucidate the encoding mechanism of pure tones, observe the changes of IC gamma-amino butyric acid (GABA) after cochlear damage by acoustic trauma and understand the possible mechanism of symptoms such as noise-induced tinnitus, hyperacusis and loudness recruitment. METHODS: The responses of IC neurons to pure tone stimuli were observed in guinea pig at Day 1 and Days 11-21 after cochlear damage induced by noise exposure. And the IC neurons of normal guinea pig were assigned as the controls. Reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the concentrations of GABA(A) and GABA(B) receptors. RESULTS: (1) The types of frequency reaction area (FRA) in the experiment group were the same as those in the control group (V-shape 84.8%, W-shape 8.9%, N-shape 6.3%). But the percentages of types were markedly different at Day 1 (V-shape 63.9%, W-shape 18.1%, N-shape, 18.1%) and Days 11-21 (V-shape 84.2%, W-shape 12.3%, N-shape 3.5%) after noise exposure. (2) After noise exposure, there was a marked fault in characteristic frequency (CF) and depth function map corresponding to 4 kHz (noise frequency). The rake ratio of CF and depth linear function map in the experiment group was lower than that of the control group. The control group, Day 1 and Days 11-21 after noise exposure, the rake ratios were 6.6, 5.8, 5.2 respectively. (3) GABA(A)/GABA(B) receptors decreased markedly at Days 1, 11 and 21 post-exposure compared to normal controls. And the values increased gradually with the prolonged time after exposure. The above findings conformed to the changes of electrophysiology of IC. CONCLUSIONS: After acoustic trauma, the responses of IC neurons to pure tone stimuli change with the elongation of time. It may be explained by the changes of IC GABA receptors after noise exposure.

[Diagnosis and treatment of the primary parapharyngeal space tumors].

OBJECTIVE: To study the clinical characteristics, diagnosis and surgical managements of the parapharyngeal space tumors. METHODS: A retrospective study of 40 patients with primary parapharyngeal space tumors treated from January 2006 to December 2008 in Chinese PLA General Hospital was performed. Among the 40 patients, there were male 22 patients, female 18 (45%), age ranged from 1 - 77, median 42 years old. CT scan combined with MRI was helpful to diagnose the parapharyngeal space tumor and make surgical plan. The surgical approaches include: trans-oral in 1 patient, trans-cervical approach in 22, transcervical-parotid approach in 8, vertical ramus osteotomy approach in 1, transcervical-partial bone resection in the angle of mandible in 4, transparotid approach in 2, and transcervical in combination with post auricle craniotomy approach in 2. RESULTS: All 40 patients had undergone surgical treatment. Postoperative histopathology showed benign in 28 patients and malignant in 12 patients. The tumors originating from salivary glands were in 15 patients, neurogenic tumors in 12 patients and tumors originating from other tissues were in 13 patients.Among 28 patients with benign tumors, 23 had been cured with one operation, without recurrence during following-up of 13 - 47 months, with a median of 39 months. Among 12 patients with malignant tumors, 6 patients alive (with following-up of 24 - 50 months and a median of 36 months), 3 patients died in half year after operation and 3 patients lost. The post-operative complication included Cerebrospinal fluid leak in one patient, operative field infection in 2 patients, and vagus nerve injury in 3 patients. CONCLUSIONS: Surgery is the first choice for parapharyngeal space tumors. Transcervical approach alone can apply to most tumors and a broader approach is indicated for malignant or large benign tumors. The prognosis is good for the benign lesions, but poor for the malignant tumors.

[Primary tumors at the cervicothoracic junction].

OBJECTIVE: To investigate the diagnosis and treatment of the primary tumors at the cervicothoracic junction. METHODS: We analyzed 17 cases of the tumors diagnosed by surgery and histopathology in Chinese PLA General Hospital from Mar. 2005 to Dec.2009. The clinical manifestations, the surgical approaches and surgical complications were analyzed retrospectively. RESULTS: The main partial of the tumors located in left side in 9 patients and in right side in 8 patients. The operation approaches included the lateral cervical incision (1 patient), the combined cervical and thorax incision (3 patients), the supraclavicular cervical incision (6 patients), the combined cervical incision and superior mediastinotomy (7 patients). Except 3 cases in whom the tumors surrounded or sticked to vital blood vessels or nerves had experienced subtotal resection, the remained 14 cases had total ablation. The morbidity occurred in 5 patients, including subclavian artery, vertebral artery and common carotid artery rupture, recurrent laryngeal nerve trauma, brachial plexus trauma and Horner' syndrome. The histopathology included the cyst, the venous haemangioma, the nodes cell neuroma, the fibroma, the fibrosarcoma, the liposarcoma, the myofibroblastic tumor, the ectopic hamartomas thymoma, the neurofibroma, and neurinoma. All the patients were followed up from 1 to 4.5 years post-operatively, with the mean follow-up of 25.3 months. The two malignant patients were alive being free of tumor with follow-up of 3 year and 8 months, and 2 year respectively. The three cases with tumor partial resection were all alive with tumour. The remained 12 benign cases with total tumor total ablation were all alive free of tumour. CONCLUSIONS: The histopathology of the cervicothoracic junction is diversity. But the commonest pathology is neurinoma. When the tumor is extensive, enveloping or involving the vital blood vessel and nerve, it is difficult to get total ablation, and the morbidity is very high.

[Rescue of postoperative carotid blowout in head and neck neoplasms].

OBJECTIVE: To investigate the prevention and rescuing measures of postoperative fatal bleeding induced by carotid blowout in head and neck tumors. METHODS: Seven cases with postoperative carotid bleeding treated from October 2003 to August 2009 were reviewed retrospectively. Of the patients, 6 were with common carotid blowout and one with internal carotid artery blowout. All patients underwent pre- or post-operative radiotherapy for primary head and neck tumours and 3 patients had neck defect repair with deltopectoral skin flap, frontal flap or free radial arm flap respectively. After carotid blowout bleeding, the patients were treated in time with X ray transcatheter intervention including transcatheter arterial embolization (TAE) and self-expanding covered stent implantation, followed by repairing the carotid region with appropriate myocutaneous flaps. RESULTS: Of 7 patients with carotid blowout, 5 patients were successfully rescued with X ray transcatheter intervention, of them 2 with self-expanding covered stent implantation and 2 with TAE respectively, and other 2 patients died due to rapid bleeding. Of the successfully rescued patients, 2 patients were with the repair of carotid area by pectoralis major myocutaneous flap, one by submental flap and one by local flap, but another one not with flap repair. Follow-up showed the 3 patients rescued with self-expanding covered stent implantation were survival for 6, 12, and 20 months, respectively, and the 2 patients rescued with TAE died of repeated carotid blowout in 2 and 13 months later, respectively. CONCLUSIONS: The planned and timely X ray transcatheter intervention is an effective method to treat carotid blowout bleeding in the patients underwent head and neck tumour surgeries. Compared with TAE, self-expanding covered stent implantation may be more reliable for restoring the blood supply of head and neck region, with less complications. One-stage repair of carotid region with myocutaneous flap is of great importance to protect the carotid and to promote the wound healing.

[Analysis of traumatic laryngotracheal stenosis in 63 cases].

OBJECTIVE: To explore the surgical treatment and the principle of selecting approaches in traumatic laryngotracheal stenosis. METHODS: Sixty three cases of traumatic laryngotracheal stenosis treated in the Department of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Arauy General Hospital from 1993-2006 were reviewed. The surgical treatment and the effects were analyzed. RESULTS: Among the 63 cases, 99 operations were accomplished in total, excluding tracheotomy and the closure operation for the fistula. Forty patients had experienced one operation (63.5%), 15 cases (23.8%) had 2 operations, 5 cases had 3 operations, 2 cases had 4 operations, and one case had 6 operations. Fifteen initially estimated as laryngotracheal stenosis with intact framework had supporting laryngoscopic surgery, 11 cases decannulated successfully after single operation. Primary laryngotracheal split and plasticity with T tube implantation were accomplished in 36 cases, with 20 cases decannulated. Among 10 cases experienced laryngotracheal split, skin graft in laryngotracheal cavity with T tube implantation, 7 decannulated. Among 6 cases of laryngotracheal split, pedicled hyoid flap transfer for reconstruction of the laryngotracheal framework defect, 4 cases decannulated. Tracheal and cricotracheal resection and end-end anastomosis were performed in 9 cases, 7 cases decannulated after single procedure. Two cases of subglottic stenosis with tracheoesophageal fistula were repaired with laryngotracheal plasticity in single procedure successfully. Fifty seven patients were decannulated after different procedures with variable hoarseness, within 6 months to 5 years follow-up. Six cases failed in decannulation. The decannulation rate was 90.5%. CONCLUSIONS: Traumatic laryngotracheal stenosis is a complex problem that usually needs a longer time for reconstruction and a different ways of approaches. It is necessary to evaluate the laryngotracheal framework defect, the degree and extension of stenosis systematically before operation for surgical planning.

[New surgical method for contact granuloma of larynx].

OBJECTIVE: For the purpose of improving the surgical effect of contact granuloma of larynx, a new surgical method was used and its effect observed. METHODS: Under suspension laryngoscope, a part of cartilage of vocal process of arytenoid cartilage was removed until the cartilage was covered by local soft tissue after the granuloma was excised. Among 8 patients in this group, 7 were male, 1 female. Their ages ranged from 29 to 51(median 45 years old). The courses were 1 to 9 months (median 7 months). All patients experienced 1 to 5 times operations (median 2 times). RESULTS: Using the new operative method, all 8 patients were cured for only 1 time, without recurrence followed- up for 1.5 years. CONCLUSIONS: The granuloma were very easily recurred after the operation. The reason might be related to the exposure and inflammation of the local vocal process cartilage. The difficult key of the operation is exposure of granuloma and cartilage of vocal process because of intratracheal anesthetic tube.

Responses to diotic, dichotic, and alternating phase harmonic stimuli in the inferior colliculus of guinea pigs.

Humans perceive a harmonic series as a single auditory object with a pitch equivalent to the fundamental frequency (F0) of the series. When harmonics are presented to alternate ears, the repetition rate of the waveform at each ear doubles. If the harmonics are resolved, then the pitch perceived is still equivalent to F0, suggesting the stimulus is binaurally integrated before pitch is processed. However, unresolved harmonics give rise to the doubling of pitch which would be expected from monaural processing (Bernstein and Oxenham, J. Acoust. Soc. Am., 113:3323-3334, 2003). We used similar stimuli to record responses of multi-unit clusters in the central nucleus of the inferior colliculus (IC) of anesthetized guinea pigs (urethane supplemented by fentanyl/fluanisone) to determine the nature of the representation of harmonic stimuli and to what extent there was binaural integration. We examined both the temporal and rate-tuning of IC clusters and found no evidence for binaural integration. Stimuli comprised all harmonics below 10 kHz with fundamental frequencies (F0) from 50 to 400 Hz in half-octave steps. In diotic conditions, all the harmonics were presented to both ears. In dichotic conditions, odd harmonics were presented to one ear and even harmonics to the other. Neural characteristic frequencies (CF, n = 85) were from 0.2 to 14.7 kHz; 29 had CFs below 1 kHz. The majority of clusters responded predominantly to the contralateral ear, with the dominance of the contralateral ear increasing with CF. With diotic stimuli, over half of the clusters (58%) had peaked firing rate vs. F0 functions. The most common peak F0 was 141 Hz. Almost all (98%) clusters phase locked diotically to an F0 of 50 Hz, and approximately 40% of clusters still phase locked significantly (Rayleigh coefficient >13.8) at the highest F0 tested (400 Hz). These results are consistent with the previous reports of responses to amplitude-modulated stimuli. Clusters phase locked significantly at a frequency equal to F0 for contralateral and diotic stimuli but at 2F0 for dichotic stimuli. We interpret these data as responses following the envelope periodicity in monaural channels rather than as a binaurally integrated representation.

Changes in interaural time sensitivity with interaural level differences in the inferior colliculus.

We measured interaural time difference (ITD) sensitivity of 72 cells in the inferior colliculus of the anaesthetised guinea pig as a function of frequency and interaural level difference (ILD). For many units there was a "null" frequency, where varying the ILD made no difference to the position of the peak of the ITD sensitivity. This null frequency was not necessarily at the characteristic frequency (CF): it occurred at CF in less than a third of the neurons for which we had sufficient data (14/50). Equally often, the null occurred below (15/50) and less often, above CF (8/50). The remaining (13/50) neurons showed clear phase changes, but these were erratic or parallel and no null could be attributed. In 33 of the 37 neurons with an identifiable null frequency, the peak ITD moved towards the recording side with increasing ILD, for frequencies above the null, and away for frequencies below the null. The changes in ITD sensitivity expressed as phase were maximally about 0.2-0.3 cycles. Many of the changes in response phase with ILD are in the same direction and magnitude as changes in the phase locking with sound level in auditory nerve fibres. Thus, these changes in phase sensitivity at the basilar membrane and auditory nerve are maintained through to ITD tuning in the IC. This is consistent with a coincidence detection mechanism. However, some of the more complex phenomena which we observe are consistent with convergence at the IC.

Phase-locked responses to pure tones in the inferior colliculus.

In the auditory system, some ascending pathways preserve the precise timing information present in a temporal code of frequency. This can be measured by studying responses that are phase-locked to the stimulus waveform. At each stage along a pathway, there is a reduction in the upper frequency limit of the phase-locking and an increase in the steady-state latency. In the guinea pig, phase-locked responses to pure tones have been described at various levels from auditory nerve to neocortex but not in the inferior colliculus (IC). Therefore we made recordings from 161 single units in guinea pig IC. Of these single units, 68% (110/161) showed phase-locked responses. Cells that phase-locked were mainly located in the central nucleus but also occurred in the dorsal cortex and external nucleus. The upper limiting frequency of phase-locking varied greatly between units (80-1,034 Hz) and between anatomical divisions. The upper limits in the three divisions were central nucleus, >1,000 Hz; dorsal cortex, 700 Hz; external nucleus, 320 Hz. The mean latencies also varied and were central nucleus, 8.2 +/- 2.8 (SD) ms; dorsal cortex, 17.2 ms; external nucleus, 13.3 ms. We conclude that many cells in the central nucleus receive direct inputs from the brain stem, whereas cells in the external and dorsal divisions receive input from other structures that may include the forebrain.

[Endoscopic or endoscope-assisted surgery for sinonasal malignancy].

OBJECTIVE: To discuss the feasibility and therapeutic efficacy of resection of sinonasal malignant tumours through endoscopic or endoscope-assisted surgery. METHODS: Since 1997, 11 cases of malignant tumours were resected under endoscope or by endoscope-assisted surgery. Among them, 5 patients were followed-up for more than 3 years, including one case of nasal septum squamous cell carcinoma; one case of ethmoid sinus squamous cell carcinoma; one case of maxillary sinus adenoid cystic carcinoma and two cases of olfactory neuroblastoma. RESULTS: In the patients who were followed-up for more than three years, no local recurrence was found. There was only one case of cervical lymph node metastasis found on a patient with olfactory neuroblastoma 2. 5 years after resection. Four years after operation, this patient was suspected to have extensive metastasis in meninges, and only palliative treatment was suggested. CONCLUSIONS: By endoscope or by endoscope-assisted surgery, some of selected sinonasal malignant tumours can be thoroughly resected. The advantages are mini-invasive and avoidance of facial scar so as to improve the quality of life (QOL) of patients. Large amount of cases, random clinical study with lone- term follow-up are still needed to verify the feasibility and efficacy of endoscopic or endoscope-assisted surgery.