Endoscopic nasopharyngectomy for salvage in nasopharyngeal carcinoma: a novel anatomic orientation

Endoscopic endonasal transpterygoid nasopharyngectomy: Anatomical considerations and technical note

BACKGROUND

The study was designed to identify new landmarks in the parapharyngeal segment of the internal carotid artery (ICA) for nasopharyngectomy and describe a surgical procedure of endoscopic endonasal transpterygoid nasopharyngectomy (EETPN).

METHODS

Four cadaveric specimens were injected with colored silicone and subjected to CT scanning before dissection. The nasopharyngeal skull base was exposed using the endoscopic endonasal transpterygoid approach. The clinical data of four patients with nasopharyngeal malignances who underwent EETPN were reviewed.

RESULTS

The lateral edge of the longus capitis muscle medially; the foramen lacerum, petrous apex spine and the stump of the levator veli palatini muscle superior laterally; and the upper parapharyngeal ICA laterally constitute the ICA-longus capitis muscle-petrous apex spine triangle which was a novel landmark for the upper parapharyngeal segment of the ICA.

CONCLUSION

The ICA-longus capitis muscle-petrous apex spine triangle are important landmarks of the upper parapharyngeal segment of the ICA.

Exploration of anatomical landmarks for performing an endoscopic transoral nasopharyngectomy

BACKGROUND

Performing a nasopharyngectomy via a transoral approach has been reported; however, defining landmarks to facilitate this approach has not been addressed. This study aims to explore anatomical landmarks to aid in performing a nasopharyngectomy via the transoral corridor.

METHODS

An endoscopic transoral nasopharyngectomy was performed on six cadaveric specimens (12 sides). Related anatomical landmarks were defined, and the strategy to preserve the parapharyngeal internal carotid artery (pICA) was explored.

RESULTS

An endoscopic transoral nasopharyngectomy was successfully achieved in all 12 sides. Utilizing the pterygoid hamulus as a landmark, the cartilaginous ET and attachments could be adequately exposed. Identification of the pICA is a prerequisite prior to Eustachian tube (ET) transection. The sphenoidal spine and the petrotympanic fissure could be sufficiently revealed in all 12 sides, which aided in transection of the cartilaginous ET without pICA injury. The ET and the prevertebral contents could be adequately removed via the transoral corridor.

CONCLUSION

The pterygoid hamulus, sphenoidal spine and petrotympanic fissure serve as reliable landmarks for performing a transoral nasopharyngectomy. Identification of the pICA is a prerequisite prior to transection of the ET to avoid pICA injury.

Deep learning signatures reveal multiscale intratumor heterogeneity associated with biological functions and survival in recurrent nasopharyngeal carcinoma

PURPOSE

How to discriminate different risks of recurrent nasopharyngeal carcinoma (rNPC) patients and guide individual treatment has become of great importance. This study aimed to explore the associations between deep learning signatures and biological functions as well as survival in (rNPC) patients.

METHODS

A total of 420 rNPC patients with PET/CT imaging and follow-up of overall survival (OS) were retrospectively enrolled. All patients were randomly divided into a training set (n = 269) and test set (n = 151) with a 6:4 ratio. We constructed multi-modality deep learning signatures from PET and CT images with a light-weighted deep convolutional neural network EfficienetNet-lite0 and survival loss DeepSurvLoss. An integrated nomogram was constructed incorporating clinical factors and deep learning signatures from PET/CT. Clinical nomogram and single-modality deep learning nomograms were also built for comparison. Furthermore, the association between biological functions and survival risks generated from an integrated nomogram was analyzed by RNA sequencing (RNA-seq).

RESULTS

The C-index of the integrated nomogram incorporating age, rT-stage, and deep learning PET/CT signature was 0.741 (95% CI: 0.688-0.794) in the training set and 0.732 (95% CI: 0.679-0.785) in the test set. The nomogram stratified patients into two groups with high risk and low risk in both the training set and test set with hazard ratios (HR) of 4.56 (95% CI: 2.80-7.42, p < 0.001) and 4.05 (95% CI: 2.21-7.43, p < 0.001), respectively. The C-index of the integrated nomogram was significantly higher than the clinical nomogram and single-modality nomograms. When stratified by sex, N-stage, or EBV DNA, risk prediction of our integrated nomogram was valid in all patient subgroups. Further subgroup analysis showed that patients with a low-risk could benefit from surgery and re-irradiation, while there was no difference in survival rates between patients treated by chemotherapy in the high-risk and low-risk groups. RNA sequencing (RNA-seq) of data further explored the mechanism of high- and low-risk patients from the genetic and molecular level.

CONCLUSION

Our study demonstrated that PET/CT-based deep learning signatures showed satisfactory prognostic predictive performance in rNPC patients. The nomogram incorporating deep learning signatures successfully divided patients into different risks and had great potential to guide individual treatment: patients with a low-risk were supposed to be treated with surgery and re-irradiation, while for high-risk patients, the application of palliative chemotherapy may be sufficient.

Endoscopic transoral nasopharyngectomy

BACKGROUND

A minimal access technique for the management of nasopharyngeal tumors extending below the palatal plane and laterally beyond the pterygoid musculature is yet to be developed. In this study we demonstrate the feasibility of endoscopic transoral nasopharyngectomy (ETON) for resection of large nasopharyngeal lesions as a natural orifice alternative to traditional approaches.

METHODS

ETON was completed in three latex-injected specimens. Surgical freedom (SF) and angles of attack (AoA) were calculated along the internal carotid artery (ICA).

RESULTS

An endoscopic transoral approach was successfully used to identify the parapharyngeal ICA and subsequently perform a complete nasopharyngeal resection. SF and AoA (sagittal) were found to be the greatest at the anterior genu of the ICA.

CONCLUSIONS

ETON is feasible. It provides wide exposure of the skull base and proximal control of the ICA. It may be indicated for the management of nasopharyngeal tumors with inferolateral extension, involving the ICA.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Establishment of a prognostic nomogram to identify optimal candidates for local treatment among patients with local recurrent nasopharyngeal carcinoma

OBJECTIVE

Thus far, there is no final conclusion on the treatment of local recurrent nasopharyngeal carcinoma (lrNPC) patients. Herein, we developed a nomogram which combined prognostic biomarkers to predict clinical outcome and guide individual treatment.

MATERIALS AND METHODS

From 2006 to 2016, 303 patients with lrNPC were retrospectively reviewed. Overall survival (OS) was the primary endpoint. The nomogram was established with the significant prognostic factors (P < 0.05) selected by multivariate analysis using Cox regression model. Harrell Concordance Index (C-index), calibration curves, and decision curve analysis (DCA) were applied to evaluate this model.

RESULTS

Four independent prognostic factors (age, hypertension, relapsed T (rT) stage, and Epstein-Barr virus DNA) identified from multivariable analysis were included into the nomogram. The C-index of the nomogram was 0.687. The calibration curves for 1-, 3-, and 5-year OS rate showed satisfactory agreements between the predicted and actual values. The decision curve analysis also exhibited a preferable net benefit of this model. All patients were subdivided into three risk groups based on the nomogram. Local treatment was associated with higher OS than palliative chemotherapy alone in the low (P < 0.001) and intermediate-risk groups (P = 0.001). However, no significant difference was observed between different treatment methods in the high-risk group (P = 0.176).

CONCLUSION

We established the nomogram for patients with lrNPC to predict OS and guide individual treatment, which showed satisfactory performance in accuracy, discrimination capability, and clinical utility.

An endoscopic anatomical study of the levator veli palatini and its relationship to the parapharyngeal internal carotid artery

BACKGROUND

The objectives of this study are to describe the levator veli palatini (LVP) as a landmark for the parapharyngeal internal carotid artery (pICA) and the endoscopic course of the pICA.

METHODS

Cadaver dissection and illustrative case study.

RESULTS

Seven cadaveric heads (12 sides) were dissected. In all 12 sides, the LVP was consistently located between the Eustachian tube and the pICA near the skull base, making the LVP just anterior to and the closest structure to the pICA. The distance between the pICA and the nares ranged from 9.0 to 12.7 cm. The distance between the pICA and the midpoint of the nasopharynx ranged from 1.9 to 3.7 cm. The case study illustrated the applicability of these findings.

CONCLUSION

The LVP is a reliable and precise landmark for the pICA. A safe working distance to the pICA is 1.9 cm from the midpoint of the nasopharynx and 9.0 cm from the nares.

Cervical-transoral robotic nasopharyngectomy: A preclinical study

BACKGROUND

We performed a preclinical study to assess the feasibility of the cervical-transoral robotic pharyngectomy procedure in surgery for nasopharyngeal cancer, where deep margins and vascular safety are key issues.

MATERIALS AND METHODS

Four cadaveric dissections were performed with the da Vinci Xi system. The first step was a robotic parapharyngeal dissection along the internal carotid artery (ICA). The second step was a type 3 transoral robotic nasopharyngectomy.

RESULTS

In each procedure, a comprehensive dissection of the parapharyngeal space was performed along the ICA up to the foramen lacerum. A type 3 nasopharyngectomy was performed transorally with an "en-bloc" removal of the parapharyngeal space, and with complete removal of the eustachian tube up to its bony part.

CONCLUSION

A comprehensive cervical-transoral robotic type 3 nasopharyngectomy with "en-bloc" removal of the parapharyngeal space and the eustachian tube proved to be technically feasible in a preclinical study.

Clinical Characteristics and Endoscopic Endonasal Removal of Foreign Bodies within Sinuses, Orbit, and Skull Base

Background:

Foreign bodies within the sinuses, orbit, and skull base (FBSOS) are rare; hence, diagnosis and management guidelines are lacking. Endoscopic sinus surgery (ESS) removal is preferred because of the less invasiveness and minimal morbidity. This study was designed to summarize clinical experience with ESS management of FBSOS.

Methods:

We retrospectively reviewed clinical manifestations, imaging findings, treatment, and outcomes in consecutive patients with ESS removal of FBSOS between 2004 and 2015 at a tertiary academic medical center. The Chi-square test was performed to compare the infection rate between wooden and nonwooden FBSOS.

Results:

There were 23 male and five female patients, with median age of 11 years. FBSOS were located within the sinuses (86%), orbit (75%), and skull base/intracranial region (46%). Wooden FBSOS had a significantly higher risk of infection (78%) compared with nonwooden FBSOS (5%, P < 0.05). Contrast-enhanced computed tomography (CT) plus three-dimensional reconstruction was sensitive in all cases. Twenty-seven (96%) FBSOS were removed by ESS alone, while 1 (4%) FBSOS was removed using the combined ESS and lateral cervical approach. Four of the nine intracranial penetrating FBSOS patients had intraoperative cerebrospinal fluid (CSF) leak and received endoscopic CSF leak repair. Twelve (43%) patients suffered complications (meningitis, diplopia, and vision loss).

Conclusions:

ESS is a minimally invasive, safe, and promising surgical approach for FBSOS removal. Contrast-enhanced CT is effective in preoperative diagnosis and intraoperative guidance. Wooden FBSOS had higher risk of infection, thus antibiotics are recommended.

Extended endonasal approach versus maxillary swing approach to the parapharyngeal space

BACKGROUND

The nasopharyngeal and parapharyngeal spaces are difficult for surgeons to access. Of the various external routes described, the maxillary swing has emerged as the gold standard because of its simplicity. However, its morbidity has led to the development of less invasive techniques. The purpose of our study was to compare the surgical anatomy of the maxillary swing with that of the endoscopic endonasal approach.

METHODS

Each procedure was performed on 10 anatomic specimens. The exposure and the limits obtained were evaluated. A CT scan analysis was performed.

RESULTS

The endoscopic endonasal approach extended the limits, offering wider exposure. The endoscopic endonasal approach made possible better visualization of deep structures and precise dissection of the parapharyngeal spaces. However, the maxillary swing provided better access to the oropharynx and could be completed 3 times faster.

CONCLUSION

The endoscopic endonasal approach provides excellent exposure, a wide dissection range, and precise definition of anatomic structures, making it an alternative of choice rather than the maxillary swing approach.

Volumetric Analysis of Endoscopic and Maxillary Swing Surgical Approaches for Nasopharyngectomy

Objectives/Hypothesis  The endoscopic endonasal approach (EEA) for nasopharyngectomy is an alternative to the maxillary swing approach (MSA) for selected recurrent nasopharyngeal carcinomas (NPC). We compare the access between these approaches. Methods  Three cadaver specimens were used to compare access volumes of the EEA and MSA. Exposure volumes were calculated using image guidance registration to cone beam computed tomography and tracking of accessible tissue with volumetric quantification. The area of exposure to the carotid artery was measured. Results  The MSA provided higher volumes for access volume compared with the EEA (66.6 vs 39.1 cm ³ , p  = 0.009). The working area was larger in the MSA (80.2 vs 56.9 cm ² , p  = 0.06). The exposure to the carotid artery was higher in the MSA (1.88 vs 1.62 cm ² , p  = 0.04). The MSA provided larger volume of exposure for tumors of the parapharyngeal space with exposure below the palate. Conclusions  This study suggests that the MSA for nasopharyngectomy provides a larger volume of exposure. However, much of the increased exposure relates to exposure of the parapharyngeal space below the palate. The EEA provides adequate access to superior anatomical structures.

Anatomy Relationship around Internal Carotid Artery in the Endoscopic Surgery of Nasopharynx: A Study Based on Computed Tomography Angiography

Objective Anatomic knowledge is needed to avoid injury to internal carotid artery (ICA) during the endoscopic surgery around nasopharynx and its surrounding space. Design We prospectively studied the computed tomography angiography (CTA) data of 28 patients with image processing software. Special attention was given to ICA and various landmarks around nasopharynx. Results The anatomic relationship between ICA and different landmarks around nasopharynx was clearly presented in three-dimension. The fossa of Rosenmuller is the nearest point of the nasopharyngeal cavity to ICA. The opening of the Vidian canal in the middle cranial fossa could be either above, below, or at the level of the horizontal segment of petrous ICA. The pharyngeal trunk of the ascending pharyngeal artery can also be clearly identified in most reconstructed CTA images. Multiple anatomic relationships were also quantified. Conclusions Reconstructed CTA can provide key anatomic information for a safe and accurate endoscopic dissection around nasopharynx.

Robotic nasopharyngectomy via combined endonasal and transantral port: a preliminary cadaveric study

OBJECTIVES/HYPOTHESIS

The objective of this study was to determine the potential role of a surgical robotic system in nasopharyngeal surgery using bilateral transantral or combined endonasal/transantral port.

STUDY DESIGN

The da Vinci robot (Intuitive Surgical Inc., Sunnyvale, CA) was used to perform dissection of the skull base on a whole fresh-frozen cadaver.

METHODS

Bilateral mega-antrostomy was done with the usual endoscopic sinus surgery equipment. To obtain an accessible bilateral working space, posterior septectomy was performed. Next, bilateral anterior maxillary windows were created through a gingivobuccal incision. The 8.5-mm-diameter 0° or 30° three-dimensional camera arm was introduced into a nostril. The two 5-mm-diameter articulating EndoWrist arms entered through the transantral or endonasal port. For the dissection, Maryland articulated forceps, needle driver, and monopolar spatula- or hook-type electrocauterizer were used.

RESULTS

The 8.5-mm diameter of the camera arm was easily inserted into the nostril. Excellent access to the nasopharyngeal area from the level of the palate up to the skull base crossing the sphenoid prow was possible. Bilateral robotic arms were able to move inside the nasopharyngeal space, and the target dissection area could be accessed fully via the transantral or endonasal port.

CONCLUSIONS

This is the first report about the feasibility of bilateral transantral or combined transantral/endonasal port for robotic nasopharyngectomy. Robotic removal of the entire nasopharyngeal area was successfully achieved without transpalatal or facial skin incision. These new approaches may be applied to selected patients with nasopharyngeal carcinoma or other pathologic tumors involving the nasopharynx.

LEVEL OF EVIDENCE

NA

Johann Christian Rosenmüller (1771-1820): A Historical Perspective on the Man behind the Fossa

Introduction The fossa of Rosenmüller, also known as the lateral pharyngeal recess, is a well-established site of origin of nasopharyngeal carcinoma. It is located in the lateral pharyngeal wall behind the cartilaginous portion of the Eustachian tube, the torus tubarius, and is named after Johann Christian Rosenmüller (JCR). Objective We present a history on the life and extensive works of Johann Christian Rosenmüller, a German physician and anatomist. Results Johann Christian Rosenmüller was a dedicated anatomist. In addition to identifying the fossa of Rosenmüller, his influence extends to various other anatomic subjects, including the Rosenmüller gland, the palpebral portion of the lacrimal gland, and the organ of Rosenmüller (i.e., the caudal remnant of the mesonephric duct). He was also an avid speleologist, studying the composition of caves and their life forms. For his contributions to this field, he had a cave in Germany and an extinct species named after him-Rosenmüllerhöhle and Ursus spelaeus Rosenmüller, respectively. Conclusion The fossa of Rosenmüller plays an important role in the growth and surgical treatment of nasopharyngeal carcinoma. We present a brief glimpse into the life of Johann Christian Rosenmüller, for whom it was named.

Combined transoral robotic surgery and endoscopic endonasal approach for the resection of extensive malignancies of the skull base

BACKGROUND

Oncologic resection of the clivus, nasopharynx, craniovertebral junction, and infratemporal fossa is a challenging endeavor because of their complex and protected anatomy. Our goals were to design a cadaveric model and identify advantages and limitations of combining the transoral robotic surgery (TORS) and endoscopic endonasal approach (EEA) techniques.

METHODS

Cadaveric specimens were dissected using a da Vinci surgical robot and endoscopic endonasal instruments in a fashion that mimicked our operating room environment. We then applied these techniques clinically.

RESULTS

EEA was performed to provide a detailed dissection of the infratemporal fossa, nasopharynx, posterior skull base (clivus), and craniovertebral junction. Using TORS, we dissected the parapharyngeal space, infratemporal fossa, and nasopharynx below the eustachian tube, which represented a transition zone that delineated the most effective resection field of each approach.

CONCLUSIONS

TORS and EEA seem to be complementary techniques; thus, their combined use seems advantageous for selected advanced tumors in these complex areas.

An endonasal approach to the resection of a papillary seromucinous adenocarcinoma of the eustacian tube

Objectives

Papillary seromucinous adenocarcinoma of the sinonasal tract is exceedingly rare. The objectives of this case report are to describe a case of papillary seromucinous adenocarcinoma presenting in the nasopharynx and to review the literature pertaining to other similar cases.

Methods

A review of the patient's chart and a review of the English literature were conducted.

Results

We describe the case of a 64 year-old woman who presented with a 3-year history of epistaxis and right-sided otitis media with effusion. The patient had been followed for a known nasopharyngeal mass that had twice been biopsied and in both cases was considered a benign mass pathologically. A third biopsy was diagnosed as a low-grade papillary seromucinous adenocarcinoma. The patient was otherwise asymptomatic. The patient was referred to a multidisciplinary cancer clinic at which endoscopic resection was determined to be the preferred treatment modality. A literature review and approach to patients with nasopharyngeal masses will be presented.

Conclusions

Papillary seromucinous adenocarcinoma is a rare tumor that can present in the nasopharynx. We describe the endoscopic surgical management of one such patient that presented to our care.

Endoscopic nasopharyngectomy and its role in managing locally recurrent nasopharyngeal carcinoma

Local recurrence after primary radiation of nasopharyngeal carcinoma (NPC) remains an important cause of morbidity and mortality. Salvage treatment using reirradiation or surgery has been shown to improve survival over nontreatment. Surgery is traditionally performed using an open approach. Advances in endoscopic approaches for resection of paranasal sinus tumors have been extended to NPC. This article reviews the treatment options, in particular the role of endoscopic nasopharyngectomy in the management of recurrent NPC. The endoscopic anatomy, surgical principles, and published results on endoscopic nasopharyngectomy are presented. Short-term outcomes for early-stage recurrences are promising but long-term follow-up is needed.

Recurrent nasopharyngeal carcinoma: surgical salvage vs. additional chemoradiation

PURPOSE OF REVIEW

The primary treatment modality of nasopharyngeal carcinoma (NPC) is radiation or chemoradiation. With the application of conformal radiation and appropriate chemotherapeutic agents, there was marked improvement in the outcome. Despite this, a small number of patients still develop residual or recurrent disease either in the neck or at the primary site. In recent years there are many developments in the disciplines of surgery, radiation and medical oncology which are applicable for the management of residual or recurrent NPC. It is timely to review the applicability and efficacy of the various therapeutic options.

RECENT FINDINGS

The theme of the literature review included the management of these recurrent or residual diseases in the neck or nasopharynx with open or endoscopic or robot-assisted surgical approaches. The application of radiation techniques such as intensity modulated radiotherapy, stereotactic radiation and brachytherapy was also included. The use of chemotherapy and targeted agents is also reviewed.

SUMMARY

In general, the size, extent and location of the residual or recurrent NPC together with the biological behaviour of the tumour determine the optimal therapy. The surgical and clinical oncological expertise applied optimally will give the best outcome.

Different therapeutic strategies in primary salivary gland-type nasopharyngeal carcinomas

PURPOSE OF REVIEW

Primary salivary gland-type nasopharyngeal carcinoma (PSGT-NPC) is an uncommon malignancy with aggressive behavior and poor prognosis. Its optimal treatment policy remains debated, even though recent evidence provides support for a multimodality approach. The aim of this study was to summarize the optimal management approaches and treatment outcomes of PSGT-NPCs.

RECENT FINDINGS

As most of the PSGT-NPCs, such as adenoid cystic carcinoma, mucoepidermoid carcinoma and low-grade (well-differentiated) adenocarcinoma, have low sensitivity to radiation, combined surgical treatment and radiotherapy are still the main treatment approach for limited or resectable lesions. As a result of the fact that in well-differentiated PSGT-NPCs the occult neck metastasis rate is low (less than 20%), elective neck dissection is not recommended in patients with a node-negative neck. Since high-grade (poorly-differentiated) PSGT-NPCs are relatively sensitive to radiation, radiotherapy or chemoradiotherapy is currently considered as the main treatment policy for such patients. There is no evidence to indicate that chemotherapy would improve overall survival. Cranial nerve infiltration, residual tumor, and distant metastases are independent predictive factors of overall survival.

SUMMARY

In most patients with PSGT-NPCs, especially for well-differentiated tumors, combined surgical treatment and radiotherapy should be recommended. For poorly-differentiated or unresectable tumors, radiotherapy or chemoradiotherapy is still considered the main treatment approach. Because of the rare incidence of PSGT-NPCs, the number of cases available for analysis is relatively small, and large multicentric studies should be conducted to further evaluate their optimal treatment policy.