The limits of endoscopic endonasal approaches in young children: a review

Special Considerations in Pediatric Endoscopic Skull Base Surgery

Originally pioneered in adults, endoscopic endonasal approaches for skull base pathology are being increasingly applied as a minimally invasive alternative for young children. Intrinsic anatomic differences between these patient populations have sparked discussions on the feasibility, safety, and efficacy of these techniques in pediatric patients. This work aims to serve as a primer for clinicians engaged in the rapidly evolving field of pediatric endoscopic skull base surgery. A succinct overview of relevant embryology, sinonasal anatomy, and diagnostic workup is presented to emphasize key differences and unique technical considerations. Additional discussions regarding select skull base lesions, reconstructive paradigms, potential surgical complications, and postoperative care are also highlighted in the setting of multidisciplinary teams.

Comparing Surgical Approaches for Craniopharyngioma Resection Among Adults and Children: A Meta-analysis and Systematic Review

BACKGROUND

Craniopharyngioma treatment often necessitates surgical resection. Conventional approaches, such as transcranial and transsphenoidal approaches, are predominantly used. However, a recently adopted supraorbital approach may be more efficacious. Thus, this meta-analysis and systematic review aimed to compare the efficacy of the transcranial, transsphenoidal, and supraorbital approaches for resection and treatment of craniopharyngiomas.

METHODS

This study was performed following PRISMA guidelines. Analyses were performed according to study design: (1) analyses for studies comparing several surgical approaches; and (2) analyses of all included studies. Random effects meta-analysis models were used to pool odds ratios among studies comparing several approaches. Similarly, categorical meta-regression models were used to examine the effect of surgical approach as a covariate of outcome data for all studies. Statistics were performed using Comprehensive Meta-Analysis software (CMA 3.3, Biostat, Englewood, NJ) (significance set at P < 0.05).

RESULTS

Patients were well-matched for age, sex, and preoperative comorbidities between groups stratified by surgical approach. Analyses including 22 studies that compared several approaches demonstrated that the transsphenoidal group had a greater occurrence of postoperative visual improvement (P < 0.0001), lesser occurrence of visual deterioration (P < 0.0001), and lower tumor recurrence rate (P = 0.015) compared with the transcranial group. Only 2 studies compared the supraorbital approach to another approach, limiting analyses. Analyses including all studies demonstrated that the supraorbital group did not differ to either the transcranial or transsphenoidal group for any examined variables.

CONCLUSIONS

The present study suggests that the transsphenoidal approach is associated with improved clinical outcomes for craniopharyngioma resection. There are limited data regarding the supraorbital approach, warranting future investigation.

Minimally invasive endoscopic approaches to pediatric skull base pathologies

OBJECTIVE

Endoscopic endonasal approaches to pediatric skull base lesions are rare, challenging, and present distinct considerations from adult pathology. In this study, we describe our endoscopic technical approach to various skull base lesions demonstrating the efficacy and nuances of these approaches in pediatric patients.

METHODS

Pediatric patients underwent endoscopic approach for skull base lesions from January of 2015 to April of 2021 were included in the study. Presenting symptoms, indications for surgery, surgical outcomes, intraoperative and postoperative complications, length of hospital stay, and length of follow-up were documented.

RESULTS

A total of 18 patients (median age 12, age-range 1-15, 53% male) underwent 19 endoscopic transsphenoidal procedures. The pathologies included craniopharyngioma (N = 5), biopsy for an unknown disease (n = 2; orbital meningioma and pituitary lymphocytic hypophysitis), pituitary adenoma (N = 2; ACTH-secreting and non-functional), Rathke's cleft cyst (n = 2), CSF leak repairs (n = 2; post-traumatic and spontaneous meningocele), juvenile nasopharyngeal angiofibroma (n = 3, 1 patient had 2 procedures) and rhabdomyosarcoma (n = 1). GTR was achieved in 11 out of 15 procedures (73.3%). Out of 10 patients with a sellar lesion, 6 patients had intraoperative CSF leak (60%). No patients experienced post-operative CSF leak. The median follow-up for all patients was 14 months (1-36 months).

CONCLUSION

Anterior and middle skull base pathology in pediatric patients can be effectively operated via an endoscopic approach across a wide variety of patient ages and conditions. Minimally invasive techniques with middle turbinate and nasal septum preservation can be achieved without compromising outcomes. A wide variety of surgical repair strategies can be successfully utilized.

Anatomic Parameters and Growth of the Pediatric Skull Base: Endonasal Access Implications

Objectives: Endoscopic endonasal anterior skull base surgery has expanding use in the pediatric population, but the anatomy of pediatric patients can lead to limitations. This study aims to characterize the important anatomical implications of the pediatric skull base using computed tomography (CT) scans. Design: Retrospective analysis Setting: Tertiary academic medical center Participants: 506 patients aged 0-18 who had undergone maxillofacial and or head CTs between 2009-2016. Methods: Measurements included piriform aperture width, nare to sella distance (NSD), sphenoid pneumatization, olfactory fossa depth, lateral lamella cribriform plate angles, and intercarotid distances (ICD) at the superior clivus and cavernous sinus. These patients were then subdivided into 3 age groups adjusting for sex. ANCOVA models were fit comparing between all age groups and by sex. Results: Piriform aperture width, NSD, sphenoid sinus pneumatization as measured using lateral aeration and anterior sellar wall thickness, olfactory fossa depth, and ICD at the cavernous sinus was significantly different among all age groups (P<0.0001). Our results show that mean piriform aperture width increased with each age group. The mean olfactory fossa depth also had consistent age dependent growth. In addition, ICD at the cavernous sinus showed age dependent changes. When comparing by sexes, females consistently showed smaller measurements. Conclusion: The process of skull base development is age and sex dependent. During preoperative evaluation of pediatric patients for skull base surgery piriform aperture width, sphenoid pneumatization in both the anterior posterior and lateral directions, and ICD at the cavernous sinus should be carefully reviewed.  

Clinical outcomes of coblation-assisted pediatric endoscopic endonasal skull base surgery

BACKGROUND

Pediatric skull base surgeries are confined by developmental and anatomical issues. Radiofrequency coblation integrates the functions of ablation, suction, and coagulation with the ability to dissolve tissues with limited thermal injury, making it an ideal instrument for pediatric skull base surgery. We sought to evaluated the clinical outcomes of coblation-assisted pediatric endoscopic skull base surgery.

METHODS

Medical records of patients under 15 years of age undergoing endoscopic skull base surgery were retrospectively reviewed. The estimated blood loss (EBL)/operating time (OT) and Wormald grade were used for intraoperative blood loss grading.

RESULTS

Generally, 28 patients (17 males, 11 females) with an average age of 8.4 ± 4.2 years, (range, 11 months to 15 years old) were included. Coblation was applied in 20 patients for mucosa coagulation and handling, cartilage removal, tumor separation and excision. The primary diagnoses included juvenile nasopharyngeal angiofibroma (n = 5), traumatic cerebrospinal fluid (CSF) leak (n = 6), congenital meningoencephalocele (n = 6) and miscellaneous sinonasal and skull base neoplasm (n = 11). The application of coblation was related with a significant decrease in EBL/OT (34.1 ± 17.5 vs 56.3 ± 22.6 ml/h, p = 0.048) and Wormald grade (5.7 ± 1.5 vs 6.9 ± 2.0, p = 0.038), compared with the traditional techniques. All surgical procedures were uneventful. No significant difference in postoperative complications, including cranial nerve dysfunction and CSF rhinorrhea were documented during the follow-up period (average, 34.7 ± 4.4 months).

CONCLUSION

We suggested the coblation be a safe and effective instrument for pediatric skull base surgery.

Maturation of the sella turcica and parasellar region: Surgical relevance for anterior skull base approaches in pediatric patients

OBJECTIVE

Traditional and extended transnasal transsphenoidal approaches provide direct access to a variety of anterior skull base pathologies. Despite increased utilization of transnasal approaches in children, anatomic studies on pediatric skull base maturation are limited. We herein perform a surgically relevant morphometric analysis of the sella and parasellar regions during pediatric maturation.

METHODS

Measurements of sellar length (SL), sellar depth (SDp), sellar diameter (SDm), interclinoid distance (ID), intercavernous distance (ICD), and the presence of sphenoid sinus pneumatization (SSP), and sphenoid sinus type (SST) were made on thin-cut CT scans from 60 patients (evenly grouped by ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 years) for analysis. Data were analyzed by sex and age groups using t-tests and linear regression.

RESULTS

Sella and parasellar parameters did not differ by sex. SL steadily increased from 8.5 ± 1.2 mm to 11.5 ± 1.6 mm throughout development. SDp and SDm increased from 6.0 ± 0.9 mm to 9.3 ± 1.4 mm and 9.0 ± 1.6 mm to 14.4 ± 1.8 mm during maturation, with significant interval growth from ages 16-18 to adult (p < 0.01). ID displayed significant growth from ages 0-3 to 4-7 (18.0 ± 2.4 mm to 20.7 ± 1.9 mm; p = 0.002) and ICD from ages 0-3 to 8-11 (12.0 ± 1.8 mm to 13.5 ± 2.1 mm; p < 0.001), without further significant interval growth. SSP was not seen in patients < 3, but was 100% by ages 8-11. SSTs progressed from conchal/presellar (60% at ages 4-7) to sellar/postsellar (80% at adulthood).

CONCLUSION

The sella and parasellar regions have varied growth patterns with development. Knowledge of the expected maturation of key anterior skull base structures may augment surgical planning in younger patients.

Endoscopic Skull Base Surgery in the Pediatric Population

Background

Surgery is often indicated for definitive biopsy or as the primary treatment modality for pediatric skull base lesions. Traditionally, open surgical approaches were utilized to address pediatric skull base pathology. However recently, expanded endoscopic sinus surgery has been utilized as a minimally invasive approach to addressing skull base pathology in the pediatric population.

Purpose

This review provides an overview of the current literature evaluating the unique anatomic challenges of the pediatric skull and the safety and efficacy of expanded skull base procedures in the pediatric population.

Findings

The pediatric skull base and sinus anatomy is small and continues to develop throughout childhood leading to unique surgical challenges. Sphenoid sinus pneumatization and intercarotid distance at the skull base are two significant anatomic challenges to pediatric skull base surgery. Despite the distinctive anatomy challenges, recent studies demonstrate that the safety and efficacy of expanded endoscopic sinus surgery appear to be equivalent to traditional open surgical approaches.

Conclusion

Expanded endoscopic sinus surgery in the pediatric population has similar efficacy and safety as the traditional open approaches.

First experience with augmented reality neuronavigation in endoscopic assisted midline skull base pathologies in children

INTRODUCTION

Endoscopic skull base approaches are broadly used in modern neurosurgery. The support of neuronavigation can help to effectively target the lesion avoiding complications. In children, endoscopic-assisted skull base surgery in combination with navigation systems becomes even more important because of the morphological variability and rare diseases affecting the sellar and parasellar regions. This paper aims to analyze our first experience on augmented reality navigation in endoscopic skull base surgery in a pediatric case series.

PATIENTS AND METHODS

A retrospective review identified seventeen endoscopic-assisted endonasal or transoral procedures performed in an interdisciplinary setting in a period between October 2011 and May 2020. In all the cases, the surgical target was a lesion in the sellar or parasellar region. Clinical conditions, MRI appearance, intraoperative conditions, postoperative MRI, possible complications, and outcomes were analyzed.

RESULTS

The mean age of our patients was 14.5 ± 2.4 years. The diagnosis varied, but craniopharyngiomas (31.2%) were mostly represented. AR navigation was experienced to be very helpful for effectively targeting the lesion and defining the intraoperative extension of the pathology. In 65% of the oncologic cases, a radical removal was proven in postoperative MRI. The mean follow-up was 89 ± 79 months. There were no deaths in our series. No long-term complications were registered; two cerebrospinal fluid (CSF) fistulas and a secondary abscess required further surgery.

CONCLUSION

The implementation of augmented reality to endoscopic-assisted neuronavigated procedures within the skull base was feasible and did provide relevant information directly in the endoscopic field of view and was experienced to be useful in the pediatric cases, where anatomical variability and rarity of the pathologies make surgery more challenging.

Outcomes of Endoscopic Versus Open Skull Base Surgery in Pediatric Patients

OBJECTIVE/HYPOTHESIS

To characterize the pathology and outcomes of skull base surgery in the pediatric population by open versus endoscopic surgical approach.

STUDY DESIGN

Retrospective cohort study.

METHODS

A retrospective review of pediatric patients (<18 years) who underwent skull base surgery for nonmalignant disease from May 2000 to August 2019 was performed. Patient demographics, pathology, and operative characteristics by surgical approach were recorded and analyzed. Patients with a combined endoscopic/open approach were classified as open for the analysis.

RESULTS

Eighty-two pediatric skull base patients were identified with a mean age of 11.3 years (standard deviation 5.2). A purely endoscopic approach was used in 63 (77%) patients, a purely open approach was used in nine (11%) patients, and a combined open/endoscopic approach was used in 10 (12%) patients. The all-cause complication rate was 9.8%. There was no statistically significant difference in rate of complications between patients with an open versus endoscopic approach for resection (15.8% vs. 7.9%; P = .379). Risk of having a complication did not significantly vary by patient age. The odds of having a complication with an open approach was not statistically significant in a multivariable model adjusted for age, sex, race, intraoperative cerebrospinal fluid leak, tracheostomy requirement, and vascular flap use (odds ratio 2.76, 95% confidence interval 0.28-26.94; P = .383).

CONCLUSIONS

Our retrospective study demonstrates a similar risk of complication for open versus endoscopic approach to resection in pediatric skull base patients at our institution. Safety and feasibility of the endoscopic approach has previously been demonstrated in children, and this is the first study to directly compare outcomes with open approaches.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:996-1001, 2021.