Clinical, anatomical, and histological features of the rhomboid lip and considerations for surgery using a retrosigmoid approach: a retrospective study.

OBJECTIVE: The rhomboid lip is a neural tissue encountered during cerebellopontine angle surgery, with differing shape and extent among individuals. This study aimed to investigate the variation of rhomboid lips during posterior fossa surgery. METHODS: In this retrospective study, we examined posterior cranial fossa surgeries performed using a retrosigmoid approach. Rhomboid lips were classified according to thickness, extent, and appearance, with some subjected to histological analysis. T2-weighted magnetic resonance imaging (MRI) of rhomboid lips was conducted. RESULTS: Among 304 surgeries, rhomboid lips were observed in 75 patients who underwent schwannoma or meningioma resection, facial spasm-related neurovascular decompression, and other surgeries (37, 2, 32, and 4 patients, respectively). Rhomboid lips were categorized based on apparent thickness: thin membranous type, resembling an arachnoid membrane, and thick parenchymal type. Rhomboid lip extension was classified by position relative to the choroid plexus: non-extension, lateral extension, and jugular foramen (41, 22, and 12 patients, respectively). Veins were observed on the rhomboid lip surface in 37 cases. The rhomboid lip was visible in only one case (parenchymal jugular foramen type) on MRI. Histologically, the rhomboid lip comprised an ependymal cell layer, a glial layer, and connecting tissue. The glial layer thickness determined the rhomboid lip thickness, which was greater in the parenchymal type than in the membrane type. In 42 patients, the rhomboid lip was dissected, with no complications observed. CONCLUSIONS: Morphological classification of the rhomboid lip and understanding of its anatomical details contribute to safe surgical field development for neurosurgeons.

Endoscopic Management of a Case of Spontaneous Cerebrospinal Fluid Leaks in Anterior Skull Base.

Spontaneous cerebrospinal fluid (sCSF) leaks are rare, and their diagnosis and treatment often present significant challenges. This paper discusses and reports cases experienced at our facility. We retrospectively reviewed three of five cases of sCSF leaks experienced at the Department of Otolaryngology and Head and Neck Surgery, Kyushu University, from December 2020 to December 2022, excluding CSF otorrhea. All three patients were female; their mean age was 56 years (44-71 years). Two of the three patients were obese (first degree), and one was average weight (according to the criteria of the Japan Society for the Study of Obesity). Two patients had hypertension, and one had sleep apnea syndrome as an underlying disease. In all cases, leakage sites, which were all the cribriform plate, can be endoscopically identified, and all could be closed by an endoscopic intranasal approach. We reviewed cases of sCSF leaks. Although some patients had difficulty identifying the leakage site in a narrow and complex nasal cavity, an endoscopic survey was useful in identifying the leakage site. All cases were closed and there were no signs of recurrence. Identifying the site of leakage and selecting the appropriate closure method depending on the extent of the leakage is essential in treating such cases.

Preservation of nasal function in paramedian endoscopic endonasal approaches: patient series.

BACKGROUND: The endoscopic endonasal approach to paramedian skull base lesions has garnered increasing attention in recent reports. However, it is still a challenging approach. While the primary objective of the approach is the maximal removal of tumors through a minimally invasive procedure, discussions of the approach rarely include information about the maximum preservation of nasal structures. This study aimed to retrospectively review the clinical outcomes of patients who had undergone an endoscopic endonasal approach to paramedian lesions, describe the technical and anatomical nuances related to this approach at the authors' institution, and discuss the maximal preservation of nasal structures. OBSERVATIONS: The authors conducted a descriptive retrospective study of 17 surgical cases of paramedian endoscopic endonasal approaches performed jointly by otolaryngologists and neurosurgeons from August 2018 to August 2022 at a tertiary hospital. LESSONS: The approach to the paramedian region of the skull base was examined. Creating an appropriate corridor to maximize the surgical field is essential to allow a safe and accurate procedure. From an otolaryngologist's perspective, the endoscopic modified medial maxillectomy is an essential procedure that maximizes the surgical corridor and maximally preserves nasal morphology. https://thejns.org/doi/10.3171/CASE24218.

Correction: Effectiveness and safety of weekly paclitaxel and cetuximab as a salvage chemotherapy following immune checkpoint inhibitors for recurrent or metastatic head and neck squamous cell carcinoma: a multicenter clinical study.

[This corrects the article DOI: 10.1371/journal.pone.0271907.].

The importance of the palatine bone for endoscopic endonasal skull base surgery.

Endoscopic endonasal skull base surgery is increasingly prevalent, with its scope expanding from pathogens in the midline region to those in the paramedian region. Maximizing anterior sphenoidectomy is important for the median approach, and lateralizing the pterygopalatine fossa is crucial for the paramedian approach. Maximizing the surgical corridor in the nasal cavity and minimizing damage to neurovascular structures are vital for establishing a surgical field with minimal bleeding, ensuring safe, precise, and gentle procedures. However, the relationship between the maxillofacial and skull base bones in endoscopic endonasal skull base surgery is difficult to understand because these bones are intricately articulated, making it challenging to visualize each bone's outline. Understanding important bones and their related neurovascular structures is essential for all skull base surgeons to maximize the surgical corridor and minimize iatrogenic injury to neurovascular structures. This study aimed to elucidate the role of the palatine bone from a microsurgical anatomical perspective. Three dry skulls were used to demonstrate the structure of the palatine bone and its relationship with surrounding bones. A formalin-perfused cadaveric head was dissected to show the related neurovascular structures. The arteries and veins of the cadaveric heads were injected with red- and blue-colored silicon. Dissection was performed using a surgical microscope and endoscope. In addition, the utilization of the palatine bone as a landmark to identify neurovascular structures, which aids in creating a wider surgical field with less bleeding, was shown in two representative cases. The palatine bone consists of unique complex structures, including the sphenoidal process, ethmoidal crest, pterygopalatine canal, and sphenopalatine notch, which are closely related to the sphenopalatine artery, maxillary nerve, and its branches. The ethmoidal crest of the palatine bone is a well-known structure that is useful for identifying the sphenopalatine foramen, controlling the sphenopalatine artery and nerve, and safely opening the pterygopalatine fossa. The sphenoidal process of the palatine bone is a valuable landmark for identifying the palatovaginal artery, which is a landmark used to safely and efficiently expose the vidian canal. The sphenoidal process is easily cracked with an osteotome and removed to expose the palatovaginal artery, which runs along the pharyngeal groove, just medial to the vidian canal. By opening the pterygopalatine canal (also known as the greater palatine canal), further lateralization of the periosteum-covered pterygopalatine fossa contents can be achieved. Overall, the sphenoidal process and ethmoidal crest can be used as important landmarks to maximize the surgical corridor and minimize unnecessary injury to neurovascular structures.

Recent advances in Otology: Current landscape and future direction.

Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.

Inhibition of PTPN3 Expressed in Activated Lymphocytes Enhances the Antitumor Effects of Anti-PD-1 Therapy in Head and Neck Cancer, Especially in Hypoxic Environments.

In the tumor microenvironment, wherein cytotoxic lymphocytes interact with cancer cells, lymphocyte exhaustion, an immune checkpoint inhibitor target, is promoted. However, the efficacy of these inhibitors is limited, and improving response rates remains challenging. We previously reported that protein tyrosine phosphatase nonreceptor type (PTPN) 3 is a potential immune checkpoint molecule for activated lymphocytes and that PTPN3 inhibition should be a focus area for cancer immunotherapy development. Therefore, in this study, we focused on PTPN3-suppressive therapy in terms of lymphocyte exhaustion under hypoxic conditions, which are a cancer microenvironment, and investigated measures for improving the response to anti-programmed death receptor (PD)-1 antibody drugs. We found that PTPN3 expression was upregulated in activated lymphocytes under hypoxic conditions, similar to the findings for other immune checkpoint molecules, such as PD-1, T cell immunoglobulin mucin-3, and lymphocyte-activation gene-3; furthermore, it functioned as a lymphocyte exhaustion marker. In addition, PTPN3-suppressed activated lymphocytes promoted the mammalian target of rapamycin (mTOR)-Akt signaling pathway activation and enhanced proliferation, migration, and cytotoxic activities under hypoxic conditions. Furthermore, PTPN3 suppression in activated lymphocytes increased PD-1 expression and enhanced the antitumor effects of anti-PD-1 antibody drugs against head and neck cancer in vitro and in vivo. These results suggest that the suppression of PTPN3 expression in activated lymphocytes enhances the therapeutic effect of anti-PD-1 antibody drugs in head and neck cancer, especially under hypoxic conditions that cause lymphocyte exhaustion.

Biological and genetic characterization of a newly established human external auditory canal carcinoma cell line, SCEACono2.

Squamous cell carcinoma of the external auditory canal (EACSCC) is an extraordinarily rare and aggressive malignant disease. Establishment of EACSCC cell line with robust molecular characteristics is essential for the basic and translational research of EACSCC. Here, we show the newly established EACSCC cell line SCEACono2, derived from a patient with well-to-moderately differentiated EACSCC. We analyzed histologic and genetic features of SCEACono2 hiring multiple experiments, including next-generation sequencing (NGS). Immunocytochemical staining of SCEACono2 showed positivity of p53 and SCC1/2. Furthermore, SCEACono2 exhibited a unique characteristic that cytokeratin, vimentin as well as cancer stem cell markers (CD44, CD133, ALP and Oct3/4) were positive. SCEACono2 had an ability to form tumors at the temporal lesion xenograft nude mice model. NGS revealed that SCEACono2 harbored the somatic mutations of TP53 (p.G245S) and NOTCH1 (p.A465T). RNA-seq and downstream bioinformatics analysis revealed significant enrichment of genes involved in inflammation and cell adhesion in SCEACono2 compared to SCC-9 and HSC-4. STR profiling indicated no evidence of cross-contamination. In conclusion, SCEACono2 could serves as a promising and robust research resource of EACSCC in vitro and in vivo.

Survival outcomes including salvage therapy of adult head and neck para-meningeal rhabdomyosarcoma: a multicenter retrospective study from Japan.

BACKGROUND: Rhabdomyosarcoma is the most common soft tissue sarcoma in children, but rare in adults. Para-meningeal rhabdomyosarcoma in head and neck (PM-HNRMS) is less applicable for surgery due to the anatomic reason. PM-HNRMS has a poor prognosis in children. However, its clinical outcomes remain unclear in adults due to the rarity. Further, there is almost no detailed data about salvage therapy. METHODS: We retrospectively examined the adult patients with PM-HNRMS treated at institutions belonging to the Kyushu Medical Oncology Group from 2009 to 2022. We evaluated the overall survival (OS) and progression-free survival (PFS) of the patients who received a first-line therapy. We also reviewed the clinical outcomes of patients who progressed against a first-line therapy and received salvage therapy. RESULTS: Total 11 patients of PM-HNRMS received a first-line therapy. The characteristics were as follows: median age: 38 years (range 25 - 63 years), histology (alveolar/spindle): 10/1, and risk group (intermediate/high): 7/4. As a first-line therapy, VAC and ARST0431-based regimen was performed in 10 and 1 patients, respectively. During a first-line therapy, definitive radiation for all lesions were performed in seven patients. The median PFS was 14.2 months (95%CI: 6.0 - 25.8 months): 17.1 months (95%CI: 6.0 - not reached (NR)) for patients with stage I-III and 8.5 months (95%CI: 5.2 - 25.8 months) for patients with stage IV. The 1-year and 3-year PFS rates were 54.5% and 11.3% for all patients. Median OS in all patients was 40.8 months (95%CI: 12.1 months-NR): 40.8 months (95%CI: 12.1 - NR) for patients with stage I-III and NR for patients with stage IV. The 5-year OS rate was 48.5% for all patients. Among seven patients who received salvage therapy, three are still alive, two of whom remain disease-free for over 4 years after completion of the last therapy. Those two patients received multi-modal therapy including local therapy for all detected lesions. CONCLUSION: The cure rate of adult PM-HNRMS is low in spite of a first-line therapy in this study. Salvage therapy might prolong the survival in patients who received the multi-modal therapy including local therapy for all detected lesions.

Impact of Positive-Margin Resection of External Auditory Canal Squamous Cell Carcinoma.

BACKGROUND: Positive-margin resection of external auditory canal squamous cell carcinoma (EAC-SCC) is still a major cause of recurrence. The aim of this study is to examine the clinical impact of positive-margin resection of EAC-SCCs. METHODS: We retrospectively reviewed 40 surgical cases with en bloc temporal bone resection of EAC-SCC at a tertiary referral center from October 2016 to March 2022. RESULTS: Two-year disease-specific, overall, and disease-free survival rates for all 40 cases reviewed were 85.2%, 88.85%, and 76.96%, respectively. En bloc resection with a negative margin significantly improved patient prognosis (p < 0.001). Positive-margin resection was observed in 9/40 cases (22.5%). Insufficient assessment of preoperative images was the cause in two of these cases. Postoperative lymph node metastasis and distant metastasis were observed in cases in which vascular, lymphatic duct or perineural invasion was found on postoperative pathological examination. In addition, three cases in which no vascular, lymphatic duct, or perineural invasion was found exhibited local recurrence during the follow-up period. Of the nine positive-margin resection cases, only two showed no postoperative recurrence. CONCLUSIONS: Once positive-margin resections are confirmed, cases might have a high risk of tumor recurrence, even with the addition of postoperative adjuvant chemoradiotherapy.

Takedown and Reuse of a Posterior Septal Nasal Floor Mucosal Flap for Skull Base Reconstruction in a Revision Surgery for a Recurrent Pituitary Tumor.

Various types of mucosal flaps can be used for skull base reconstruction after endoscopic endonasal skull base surgery (EESS). Preventing postoperative cerebrospinal fluid (CSF) leakage is essential. Flap creation during revision surgery can be problematic. We present a patient in whom a posterior septal nasal floor flap (PS-NF) was successfully reused for reconstruction after multiple reoperations for pituitary tumor resection. A 22-year-old female underwent EESS for resection of a pituitary tumor and experienced multiple recurrences after repeated operations. For the third recurrence, a skull base surgery team comprising otolaryngologists and neurosurgeons performed a binostril combined transnasal/transseptal approach and used a PS-NF for reconstruction. For the fourth recurrence, a PS-NF was successfully taken down and reused for reconstruction. No postoperative CSF leakage or intranasal complications occurred. Skull base reconstruction using a PS-NF is feasible and preserves the mucous membrane of the nasal septum and the morphology of the nasal cavity. PS-NF takedown and reuse is an option for revision EESS for recurrent pituitary tumors.

High-risk HPV-related squamous cell carcinoma in the temporal bone: a rare but noteworthy subtype.

High-risk human papillomavirus (HPV) is a risk factor for the development of several head and neck squamous cell carcinomas (SCCs). However, there have been few reports of high-risk HPV infection in temporal bone squamous cell carcinomas (TBSCCs), and thus the prevalence and clinicopathologic significance of high-risk HPV in TBSCCs are still unclear. We retrospectively collected 131 TBSCCs and analyzed them for transcriptionally active high-risk HPV infection using messenger RNA in situ hybridization; we also assessed the utility of p16-immunohistochemistry (IHC) and Rb-IHC to predict HPV infection. Eighteen (13.7%) of the 131 TBSCCs were positive for p16-IHC, and five of them were positive for high-risk HPV infection (the estimated high-risk HPV positivity rate was 3.8% [5/131]). Interestingly, all five HPV-positive patients were male and had TBSCC on the right side. In the p16-IHC+/HPV+ cases (n = 5), the Rb-IHC showed a partial loss pattern (n = 4) or complete loss pattern (n = 1). In contrast, all p16-IHC-negative cases (n = 113) showed an Rb-IHC preserved pattern. The positive predictive value (PPV) of p16-IHC positivity for high-risk HPV infection was low at 27.8%, while the combination of p16-IHC+/Rb-IHC partial loss pattern showed excellent reliability with a PPV of 100%. The prognostic significance of high-risk HPV infection remained unclear. High-risk HPV-related TBSCC is an extremely rare but noteworthy subtype.

Effectiveness and safety of weekly paclitaxel and cetuximab as a salvage chemotherapy following immune checkpoint inhibitors for recurrent or metastatic head and neck squamous cell carcinoma: A multicenter clinical study.

OBJECTIVES: The benefit of sequential therapy after immune checkpoint inhibitor (ICI) treatment for recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) has been recently reported. Furthermore, there is a growing interest in the impact of cetuximab (Cmab)-containing salvage chemotherapy (SCT) and the therapeutic efficacy and adverse events (AEs) of Cmab administration prior to ICI administration. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 52 patients with R/M HNSCC treated with SCT (weekly paclitaxel [PTX], n = 7, or weekly PTX and Cmab [PC], n = 45). RESULTS: The objective response rate (ORR) and a disease control rate (DCR) was 53.3% and 91.1% in the PC group and 42.9% and 57.1% in the PTX group, respectively. There was a significant difference in the DCR between the PC and PTX groups (p = 0.0143). The overall survival (OS) and progression-free survival were significantly better in the PC group than in the PTX group. On the other hand, the incidence of drug-induced interstitial pneumonia (DI-IP) in R/M HNSCC patients who received SCT was 21.2%. Patients in the PC group were divided according to whether they received Cmab (Group A) or did not receive Cmab (Group B) as palliative therapy prior to ICIs. Group B had a significantly better OS than Group A. Furthermore, our findings suggest that the incidence rate of DI-IP during SCT might be higher in Group B. CONCLUSION: Although PC following ICIs shows dramatic efficacy, careful monitoring of AEs, including DI-IP, is recommended.

Clinical Analysis of En Bloc Resection for Advanced Temporal Bone Squamous Cell Carcinoma.

Objective En bloc and margin-negative surgical resection seems to offer the best prognosis for patients with temporal bone squamous cell carcinoma (TB-SCC). In this study, we summarize the outcomes of surgical cases of advanced TB-SCC (T3-T4) that were managed in two institutions, with an accompanying description of the surgical procedure that was utilized: modified subtotal temporal bone resection (STBR), which involves the en bloc removal of the temporal bone including or transecting the otic capsule. Design This is a case series study with chart review. Setting The study was conducted at two academic tertiary care medical centers. Participants Chart information was collected for all patients who underwent surgical resection of advanced TB-SCC between July 1998 and February 2019. The resulting dataset contained 43 patients with advanced TB-SCC who underwent en bloc resection during the review period. Tumor staging followed the modified Pittsburgh classification. Disease-specific survival (DSS) rates were calculated according to the Kaplan-Meier method. Main Outcome Measure This study shows disease-specific 5-year DSS rate. Results The 5-year DSS rate of the cases who underwent en bloc resection was 79.7%. En bloc lateral temporal bone resection was employed in a total of 25 cases (DSS: 79.0%). En bloc modified STBR was utilized in 18 cases (DSS: 81.7%). Conclusion En bloc margin-negative resection is a reliable treatment strategy for advanced TB-SCC. Modified STBR can be a treatment option for TB-SCC without marked posterior extension.

Individualized circulating tumor DNA monitoring in head and neck squamous cell carcinoma.

There is no useful biomarker to evaluate treatment response and early relapse in head and neck squamous cell carcinoma (HNSCC). Circulating tumor DNA (ctDNA) is a promising biomarker for detecting minimal residual diseases and monitoring treatment effect. We investigated whether individualized ctDNA analysis could help monitor treatment response and relapse in HNSCC. Mutation analysis of tumor and peripheral blood mononuclear cell (PBMC) DNAs of 26 patients with HNSCC was performed using a custom squamous cell carcinoma (SCC) panel. The identified individualized mutated genes were defined as ctDNA candidates. We investigated whether frequent ctDNA monitoring via digital PCR (dPCR) is clinically valid for HNSCC patients. TP53 was the most frequently mutated gene and was detected in 14 of 24 cases (58.2%), wherein two cases were excluded owing to the absence of tumor-specific mutations in the SCC panel. Six cases were excluded because of undesignable and unusable primer-probes for dPCR. Longitudinal ctDNA was monitored in a total of 18 cases. In seven cases, ctDNA tested positive again or did not test negative, and all seven cases relapsed after initial curative treatment. In 11 cases, after initial curative treatment, ctDNA remained negative and patients were alive without recurrence. Patients who remained negative for ctDNA during follow-up after initial curative treatment (n = 11) had a significantly better prognosis than those who reverted to ctDNA positivity (n = 7; p < 0.0001; log-rank test). Individualized ctDNA monitoring using SCC panel and dPCR might be a novel and promising biomarker for HNSCC.

Endonasal endoscopic surgery for temporal lobe epilepsy associated with sphenoidal encephalocele.

BACKGROUND: Temporal lobe epilepsy (TLE) associated with temporal lobe encephalocele is rare, and the precise epileptogenic mechanisms and surgical strategies for such cases are still unknown. Although the previous studies have reported good seizure outcomes following chronic subdural electrode recording through invasive craniotomy, only few studies have reported successful epilepsy surgery through endoscopic endonasal lesionectomy. CASE DESCRIPTION: An 18-year-old man developed generalized convulsions at the age of 15 years. Despite treatment with optimal doses of antiepileptic drugs, episodes of speech and reading difficulties were observed 2-3 times per week. Long-term video electroencephalogram (EEG) revealed ictal activities starting from the left anterior temporal region. Magnetic resonance imaging revealed a temporal lobe encephalocele in the left lateral fossa of the sphenoidal sinus (sphenoidal encephalocele). Through the endoscopic endonasal approach, the tip of the encephalocele was exposed. A depth electrode was inserted into the encephalocele, which showed frequent spikes superimposed with high-frequency oscillations (HFOs) suggesting intrinsic epileptogenicity. The encephalocele was resected 8 mm from the tip. Twelve months postoperatively, the patient had no recurrence of seizures on tapering of the medication. CONCLUSION: TLE associated with sphenoidal encephalocele could be controlled with endoscopic endonasal lesionectomy, after confirming the high epileptogenicity with analysis of HFOs of intraoperative EEG recorded using an intralesional depth electrode.

Variations of en Bloc Resection for Advanced External Auditory Canal Squamous Cell Carcinoma: Detailed Anatomical Considerations.

Currently, only lateral temporal bone resection (LTBR) and subtotal temporal bone resection (STBR) are widely utilized for the surgical treatment of advanced squamous cell carcinoma of the external auditory canal (EAC-SCC). However, there are few descriptions of variations on these surgical approaches. This study aimed to elucidate the variations of en bloc resection for advanced EAC-SCC. We dissected the four sides of cadaveric heads to reveal the anatomical structures related to temporal bone resection. From the viewpoint of surgical anatomy, surgical patterns of temporal bone cutting can be divided into four categories: conventional LTBR, extended LTBR, conventional STBR, and modified STBR. Extended LTBR is divided into four types: superior, inferior, anterior, and posterior extensions. Several extension procedures can be combined based on the extension of the tumor. Furthermore, en bloc resection with the temporomandibular joint or glenoid fossa increases the technical difficulty of a surgical procedure because the exposure and manipulation of the petrous segment of the internal carotid artery are limited from the middle cranial fossa. Surgical approaches for advanced SCC of the temporal bone are diverse. They require accurate preoperative evaluation of the tumor extension and preoperative consideration of the exact line of resection to achieve marginal negative resection.

[A case of spontaneous middle cranial fossa cerebrospinal fluid leak presenting as recurrent bacterial meningitis].

A 19-year-old man with a history of Chiari type I malformation was admitted to our hospital two times within a 2-month period because of bacterial meningitis. Cerebrospinal fluid (CSF) analysis showed neutrophilic pleocytosis and hypoglycorrhachia. During the second admission, we became aware of hearing loss on the right since age 15 years. High-resolution temporal bone CT showed soft tissue opacification of the right epitympanum and external auditory canal. Tissue biopsy resulted in CSF otorrhea and pneumocephalus. CT cisternography revealed a temporal bone CSF leak. Brain MRI showed a dural defect localized to the anterior petrous apex. Using a combined middle cranial fossa-transmastoid approach, the dural defect and associated arachnoid granulations were located along the superior side of the greater petrosal nerve and repaired. A CSF leak without underlying pathology, such as trauma, surgery, or congenital abnormality, is defined as spontaneous. Spontaneous CSF leak should be considered as a cause of recurrent bacterial meningitis even when CSF otorrhea and fluid behind the tympanic membrane are clinically absent.

Management of Residual Hearing with Cartilage Conduction Hearing Aid after Lateral Temporal Bone Resection: Our Institutional Experience.

BACKGROUND: There is no guideline for hearing compensation after temporal bone resection. This study aimed to retrospectively analyze surgical cases with reconstruction for hearing preservation after temporal bone malignancy resection and propose a new alternative to compensate for hearing loss. METHODS: We retrospectively reviewed the medical records of 30 patients who underwent lateral temporal bone surgery for temporal bone malignancy at our institution and examined their hearing abilities after surgery. RESULT: The hearing outcomes of patients with an external auditory meatus reconstruction varied widely. The mean postoperative air-bone gap at 0.5, 1, 2, and 4 kHz ranged from 22.5 dB to 71.25 dB. On the other hand, the average difference between the aided sound field thresholds with cartilage conduction hearing aid and bone conduction thresholds at 0.5, 1, 2, and 4 kHz ranged from -3.75 to 41.25. More closely located auricular cartilage and temporal bone resulted in smaller differences between the aided sound field and bone conduction thresholds. CONCLUSIONS: There is still room for improvement of surgical techniques for reconstruction of the auditory meatus to preserve hearing after temporal bone resection. The cartilage conduction hearing aid may provide non-invasive postoperative hearing compensation after lateral temporal bone resection.

Establishment and characterization of a primary cell culture derived from external auditory canal squamous cell carcinoma.

There are no human cancer cell lines of external auditory canal origin available for research use. This report describes the establishment of a culture condition for external auditory canal squamous cell carcinoma, derived from human tumor tissue. Successive squamous cell carcinoma colonies were dissociated by trypsin, subcultured, and maintained on a feeder layer (MMC-TIG-1-20), yielding a clonally proliferating cell culture. Two morphological types of colony were observed: (a) densely packed colonies and (b) colonies with indistinct boundaries characterized by cell-cell complexes with fibroblast feeder cells. The SCC-like characteristics of these cells were evidenced by positivity for p53, SCCA1/2, cytokeratin, and vimentin, and cancer stem cell properties were indicated by positivity for CD44, CD133, Oct3/4, and alkaline phosphatase (ALP). One of the unique properties of cell cultures is their tendency to form steric colonies in vitro on feeder layer cells. In addition, in the presence of fresh macrophages, the cells very slowly transform to break away from colonies as free cells, a process that resembles the epidermal-mesenchymal transition, whereby cell-cell interactions are weakened and migration activity is enhanced. These factors are purported to play a key role in cancer cell metastasis.