Extended endoscopic endonasal approach to clival and paraclival tumors: Indications and limits

[Endoscopic transnasal resection of clival meningiomas]

BACKGROUND

Surgical treatment of ventral and ventrolateral meningiomas of posterior cranial fossa is difficult in modern neurosurgery. This is due to peculiarities of approach to these areas and concentration of critical structures (cranial nerves and great vessels). Currently, endoscopic transnasal approach to these meningiomas allows partial, and in some cases, total resection. However, this technique is not widespread.

OBJECTIVE

To analyze the world literature data on postoperative outcomes in patients with clival and petroclival meningiomas after endoscopic transnasal resection.

MATERIAL AND METHODS

We analyzed 22 articles representing treatment of 61 patients with clival and petroclival meningiomas.

RESULTS

Total or near-total resection was achieved in 22.9% of cases, subtotal resection - 40.9%, partial resection - 26.2% (data were not provided in other cases). Even partial and subtotal resection leads to significant regression of symptoms.

CONCLUSION

Endoscopic transnasal surgery is a full-fledged alternative to transcranial approaches in surgical treatment of clival meningiomas. It is also an additional option for patients with petroclival meningiomas after ineffective transcranial approaches. Transnasal tumor shrinkage and devascularization lead to brainstem decompression, regression of hydrocephalus and baseline clinical symptoms.

Posterior pedicle inferior turbinate flap for recurrent cerebrospinal fluid leak following endoscopic transsphenoidal surgery

BACKGROUND

Adequate reconstruction of skull base following endoscopic transsphenoidal surgery is the most crucial step in reducing postoperative morbidity and mortality. Although, the success rate of traditional nasoseptal flap is very high, specific surgical scenarios preclude its use. A variety of vascularised endonasal and tunnelled scalp flaps have been described in the literature to address such situations. Posterior pedicle inferior turbinate flap (PPITF) is one such locally available vascularised flap.

METHODS

Two patients with recurrent CSF leak following endoscopic transsphenoidal resection of pituitary adenoma were included. The nasoseptal flap was not available in both patients due to previous surgery. Hence, a PPITF based on the posterolateral nasal artery, a branch of sphenopalatine artery, was harvested and used for skull base reconstruction.

RESULTS

In both patients, CSF leak subsided in the immediate postoperative period. In one patient, sensorium improved and was subsequently discharged in stable condition. Other patient succumbed to meningitis in the postoperative period.

CONCLUSIONS

The PPITF is a valuable alternative to the conventional nasoseptal flap when the latter is not available and it is very important for an endoscopic skull base surgeon to be familiar with the technique of harvesting and using the PPITF.

Fractionated Radiotherapy After Gross Total Resection of Clival Chordoma: A Systematic Review of Survival Outcomes

BACKGROUND

Current treatment guidelines for clival chordomas recommend surgical resection followed by high-dose radiotherapy (RT). However, in patients in whom gross total resection (GTR) is achieved, the benefits of additional RT remain unclear.

OBJECTIVE

To investigate whether RT offers any benefit to progression-free survival (PFS) in patients undergoing GTR of clival chordoma by performing a systematic review of all currently published literature.

METHODS

A total of 5 databases were searched to include all studies providing data on GTR ± RT for clival chordomas (January 1990-June 2021). Qualitative assessment was performed with Newcastle-Ottawa Scale guidelines for assessing quality of nonrandomized studies. Statistical analysis using individualized patient data of PFS was performed.

RESULTS

The systematic search yielded 2979 studies, weaned to 22 full-text articles containing 108 patients. All patients underwent GTR of clival chordoma, with 46 (43%) patients receiving adjuvant RT. Mean PFS for RT patients was 31.09 months (IQR: 12.25-37.75) vs 54.92 months (IQR: 14.00-85.75) in non-RT patients. Overall, RT did not increase PFS (HR 0.320, P = .069) to a value that achieved statistical significance. Stratifying by photon therapy vs particle beam therapy yielded no statistically significant benefit for particle beam therapy for PFS ( P = .300). Of patients with age ≥65 years, RT did not improve outcomes to statistical significance for PFS (HR 0.450, P = .481). Patients age ≥65 years had lower PFS on both bivariate analysis (HR 3.708, P = .007) and multivariate analysis (HR 3.322, P = .018).

CONCLUSION

After achieving GTR of clival chordoma, fractionated RT offers unclear benefit upon survival outcomes.

[Endoscopic transnasal resection of clival meningiomas]

Treatment of clival meningiomas is still one of the unresolved issues in modern neurosurgery. There are several treatment strategies. These ones include various combinations of follow-up, surgical CSF drainage, tumor resection and radiotherapy.

OBJECTIVE

To assess postoperative outcomes in patients with clival meningiomas.

MATERIAL AND METHODS

We analyzed 18 patients with large or giant clival meningiomas.

RESULTS

We assessed extent of resection using the scale by G. Frank and E. Pasquini (2002): total resection - 95-100%, subtotal - 80-95%, partial - 50-80%, extended biopsy - <50% of tumor. Total resection was achieved in 1 patient (5.5%), subtotal - 5 (27.8%), partial - 12 (66.7%). At the same time, brainstem decompression and regression of hydrocephalus were observed in all cases. Fourteen patients were followed-up. Median follow-up was 8.5 months. Seventeen patients underwent radiotherapy due to predominant partial and subtotal resection. Total focal dose ranged from 50 to 57 Gy in standard fractionation mode. None patient had residual tumor enlargement throughout the follow-up period. There were no lethal outcomes.

CONCLUSION

Endoscopic transnasal access to clival meningiomas in appropriate anatomical features of tumor and surrounding structures is a full-fledged alternative to transcranial treatment in these patients. This approach provides total resection and brainstem decompression. These facts increase life expectancy without deterioration of the quality of life.

Surgical implementation and efficacy of endoscopic endonasal extradural posterior clinoidectomy

OBJECTIVE

The endoscopic endonasal approach (EEA) for skull base tumors has become an important topic in recent years, but its use, merits, and demerits are still being debated. Herein, the authors describe the nuances and efficacy of the endoscopic endonasal extradural posterior clinoidectomy for maximal tumor exposure.

METHODS

The surgical technique included extradural posterior clinoidectomy following lateral retraction of the paraclival internal carotid artery and extradural pituitary transposition. In cases with prominent posterior clinoid process, a midline sellar dura cut was added to facilitate extradural exposure. Forty-four consecutive patients, in whom this technique was performed between 2016 and 2018 at Osaka City University Hospital, were reviewed. The pathology included 19 craniopharyngiomas, 7 chordomas, 6 meningiomas, 6 pituitary adenomas, 4 chondrosarcomas, and 2 miscellaneous. Utilization and effectiveness of this approach were further demonstrated with neuroimaging.

RESULTS

Extradural posterior clinoidectomies were successfully applied in all patients without permanent neurovascular injury and with better maneuverability and greater resection rate of the tumors. Four patients experienced transient postoperative abducens nerve paresis, and 1 patient experienced transient postoperative oculomotor nerve paresis; however, the patients with deficits recovered within 3 months. On radiological examination, the surgical field was 2.2 times wider in cases with bilateral posterior clinoidectomy than in cases without posterior clinoidectomy.

CONCLUSIONS

The extended EEA with extradural posterior clinoidectomy creates an extra working space and allows adequate accessibility with safe surgical maneuverability to remove tumors that extend behind the posterior clinoid and dorsum sellae.

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.

Transclival approaches for intradural pathologies: historical overview and present scenario

Recently, endoscopic transsphenoidal transclival approaches have been developed and their role is widely accepted for extradural pathologies. Their application to intradural pathologies is still debated, but is undoubtedly increasing. In the past five decades, different authors have reported various extracranial, anterior transclival approaches for intradural pathologies. The aim of this review is to provide a historical overview of transclival approaches applied to intradural pathologies. PubMed was searched in October 2018 using the terms transcliv*, cliv* intradural, transsphenoidal transcliv*, transoral transcliv*, transcervical transcliv*, transsphenoidal brainstem, and transoral brainstem. Exclusion criteria included not reporting reconstruction technique, anatomical studies, reviews without new data, and transcranial approaches. Ninety-one studies were included in the systematic review. Since 1966, transcervical, transoral, transsphenoidal microsurgical, and, recently, endoscopic routes have been used as a corridor for transclival approaches to treat intradural pathologies. Each approach presents a curve that follows Scott's parabola, with evident phases of enthusiasm that quickly faded, possibly due to high post-operative CSF leak rates and other complications. It is evident that the introduction of the endoscope has led to a significant increase in reports of transclival approaches for intradural pathologies. Various reconstruction techniques and materials have been used, although rates of CSF leak remain relatively high. Transclival approaches for intradural pathologies have a long history. We are now in a new era of interest, but achieving effective dural and skull base reconstruction must still be definitively addressed, possibly with the use of newly available technologies.

Lessons learned in the evolution of endoscopic skull base surgery

OBJECTIVEEndoscopic skull base surgery (ESBS) is a relatively recent addition to the neurosurgical armamentarium. As with many new approaches, there has been significant controversy regarding its value compared with more traditional approaches to ventral skull base pathology. Although early enthusiasm for new approaches that appear less invasive is usually high, these new techniques require rigorous study to ensure that widespread implementation is in the best interest of patients.METHODSThe authors compared surgical results for ESBS with transcranial surgery (TCS) for several different pathologies over two different time periods (prior to 2012 and 2012-2017) to see how results have evolved over time. Pathologies examined were craniopharyngioma, anterior skull base meningioma, esthesioneuroblastoma, chordoma, and chondrosarcoma.RESULTSESBS offers clear advantages over TCS for most craniopharyngiomas and chordomas. For well-selected cases of planum sphenoidale and tuberculum sellae meningiomas, ESBS has similar rates of resection with higher rates of visual improvement, and more recent results with lower CSF leaks make the complication rates similar between the two approaches. TCS offers a higher rate of resection with fewer complications for olfactory groove meningiomas. ESBS is preferred for lower-grade esthesioneuroblastomas, but higher-grade tumors often still require a craniofacial approach. There are few data on chondrosarcomas, but early results show that ESBS appears to offer clear advantages for minimizing morbidity with similar rates of resection, as long as surgeons are familiar with more complex inferolateral approaches.CONCLUSIONSESBS is maturing into a well-established approach that is clearly in the patients' best interest when applied by experienced surgeons for appropriate pathology. Ongoing critical reevaluation of outcomes is essential for ensuring optimal results.

Endoscopic Endonasal Approaches for Treatment of Craniovertebral Junction Tumours

Tumours involving the craniovertebral junction (CVJ) are challenging because of their local invasiveness and high recurrence rates, as well as their proximity to critical neurovascular structures and the difficulty of reconstructing the resulting skull base defect at this site. Several surgical techniques are currently available to access these lesions, including the far lateral, extreme lateral, direct lateral, transcervical, transoral and transnasal approaches. In this paper, application of the endoscopic endonasal approach (EEA) in the treatment of CVJ tumours is analysed. The indications, contraindications, preoperative workup, step-by-step surgical technique, skull base reconstruction options and postoperative management are described. The advantages and limitations of the EEA are also discussed. Finally, a systematic review of the literature is provided to elucidate the levels of evidence supporting the use of the EEA in this field. Employment of this approach to the CVJ has contributed to high success rates in achieving gross total resection of tumours and improvement in neurological symptoms. Intraoperative and postoperative complication rates are acceptable, with cerebrospinal fluid leakage being the major concern (with a 17-25% incidence). Moreover, in comparison with traditional approaches to the CVJ, the EEA provides lower rates of postoperative dysphagia and respiratory complications. Use of the EEA for treatment of CVJ tumours appears to be a rational alternative to the conventional transoral, transcranial and transcervical approaches in selected cases. Multidisciplinary teamwork including different specialists-such as medical and radiation oncologists, radiologists, otorhinolaryngologists and neurosurgeons-is strongly recommended for the purpose of offering the best treatment strategy for the patient.

Transnasal Endoscopic and Lateral Approaches to the Clivus: A Quantitative Anatomic Study

BACKGROUND

Transnasal endoscopic approaches to the clivus have been established recently. Comparative analyses with classic lateral approaches are limited. In this study, we compared transnasal endoscopic and lateral approaches to the clivus, quantifying the exposure and working volume of each approach in the anatomy laboratory.

METHODS

High-resolution computed tomography scans were performed on 5 injected specimens (10 sides). In each specimen, transnasal endoscopic approaches (i.e., paraseptal, transrostral, extended transrostral, transethmoidal, and extended transclival without and with intradural hypophysiopexy) and lateral approaches (i.e., retrosigmoid, far-lateral, presigmoid retrolabyrinthine and translabyrinthine) to the clivus were performed. An optic neuronavigation system and dedicated software (ApproachViewer; Guided Therapeutics Program, University Health Network, Toronto, Ontario, Canada) were used to quantify the working volume and exposed clival area of each approach. Statistical evaluation was performed with the Kruskal-Wallis test and Steel-Dwass-Critchlow-Fligner post hoc test.

RESULTS

Endoscopic transnasal transclival approaches showed higher working volume and larger clival exposure compared with lateral approaches. Incremental volumetric values were evident for transnasal approaches; presigmoid approaches provided less working volume than retrosigmoid approaches. A transnasal transclival approach with hypophysiopexy provided significant exposure of the upper clivus (84.4%). The transrostral approach was the first transnasal approach providing satisfactory access to the midclivus (66%); retrosigmoid and far-lateral approaches provided exposure of approximately one half of the midclivus. The lower clivus was optimally exposed with endoscopic transclival approaches (83%), whereas access to this region was limited with lateral approaches.

CONCLUSIONS

This quantitative anatomic study shows that endoscopic transnasal approaches to the clivus provide a larger working volume and wider exposure of the clivus compared with lateral approaches.

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas

Endoscopic endonasal trans-sphenoidal surgery has become the gold standard for the surgical treatment of pituitary adenomas and many other pituitary lesions. Refinements in surgical techniques, technological advancements, and incorporation of neuronavigation have rendered this surgery minimally invasive. The complication rates of this surgery are very low while excellent results are consistently obtained through this approach. This paper focuses on the step-by-step surgical approach to pituitary adenomas, which is based on personal experience, and details the results obtained with this minimally invasive surgery.

Endoscopic approach for a delayed post-traumatic ethmoidal mucocele: a technical note

OBJECTIVE

Delayed post-traumatic mucoceles are rare. We describe the surgical treatment of a post-traumatic ethmoidal mucocele with intra-orbital extension.

METHOD

A uninostril endoscopic endonasal approach (EEA) was performed. The access was contralateral to the lesion to provide a wider lateral view. After a large sphenoid and ethmoid sinuses opening, the collection was drained and the optic nerve precociously identified. The orbital roof was eroded and the frontal dura mater directly visible.

CONCLUSION

The uninostril contralateral approach allows a good exposure of the lateral fields and is conservative towards the nasal mucosa. A favorable skull base anatomy is the prerequisite for its efficacy.