Developmental Considerations in Pediatric Skull Base Surgery

Endoscopic endonasal drainage of a middle fossa epidural abscess in conjunction with endoscopic sinus surgery: illustrative case

BACKGROUND

Recent anatomical studies have reported the feasibility of the endoscopic endonasal approach to the middle fossa. However, its clinical applicability has been discussed in only a few cases. This article describes the case of a middle fossa epidural abscess successfully drained through a fully endoscopic endonasal corridor and discusses the key technical points.

OBSERVATIONS

The authors describe an 8-year-old boy who presented with worsening headache, fatigue, emesis, and fever and was diagnosed with a left middle fossa epidural abscess associated with sphenoid sinusitis. Following endoscopic sinus surgery performed by a rhinologist, the middle fossa was accessed by removing the maxillary strut through the transmaxillary transpterygoid corridor. Complete drainage of the abscess was confirmed on postoperative magnetic resonance imaging. The patient tolerated the surgery without neurological deficit and demonstrated prompt symptom improvement. He was discharged home after completing a 6-week course of antibiotic therapy and remained free from recurrence at 1 year following surgery.

LESSONS

The endoscopic endonasal approach may be applicable to a middle fossa epidural abscess, resulting in prompt clinical improvement. The maxillary strut is a key structure for entering the middle fossa. https://thejns.org/doi/10.3171/CASE24288.

Unilateral Periorbital Swelling in a Pediatric Patient

Infratemporal fossa (ITF) tumors are rare in children and may present with a variety of symptoms. Teratomas are neoplasms derived from the 3 germ layers and approximately 6% to 10% are within the head and neck. Our study discusses one of the first reported cases of teratoma in the ITF in a pediatric patient. A 3-year-old girl presents with 2 years of recurrent monthly left periorbital swelling accompanied by fevers, skin discoloration, and pain. Prior episodes were treated with antibiotics with incomplete resolution. Imaging revealed a cystic lesion centered in the ITF. She was taken for endoscopic endonasal biopsy of the lesion and had no complications. Pathology revealed a mature teratoma composed primarily of pancreatic tissue. Providers should consider masses such as teratoma in the differential for ITF tumors and periorbital edema unresponsive to typical treatment.

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.

An Endoscopic Endonasal Attempt at Pediatric Meningoencephalocele Repair

Meningoencephalocele is an abnormal skull base protrusion of fluid, brain tissue, and meninges that can lead to nasal obstruction, meningitis, and Cerebrospinal Fluid (CSF) rhinorrhea. This condition can be managed operatively through an open craniotomy or a less invasive endoscopic approach. Here, we report a case of an 18-month-old female who presented with a meningoencephalocele that was part of the Sakoda complex, a rare neurosurgical phenomenon consisting of meningoencephalocele, agenesis of the corpus callosum, and cleft lip/palate. The patient was initially treated with the endoscopic transsphenoidal approach with subsequent open craniotomy.

Two-Stage Resection of a Giant Trigeminal Schwannoma in a Non-Neurofibromatosis Type 2 Pediatric Patient: A Case Report, Systematic Review, and Intraoperative Video

BACKGROUND

Trigeminal schwannoma is an uncommon tumor in pediatric patients. Several surgical approaches have been described in the literature.

METHODS

The case of an 11-year-old boy with a giant dumbbell-shaped trigeminal schwannoma removed through a 2-stage approach was presented with an intraoperative video. Using PubMed and Scopus, the literature on trigeminal schwannoma in pediatric patients was searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

RESULTS

The search strategy yielded 312 titles, of which 13 were included in the review. Cases of trigeminal schwannoma were described, with a highly variable clinical presentation and anatomical arrangement in cranial fossae. Two-stage approaches were reported, although most studies described single-stage approaches. Common postoperative outcomes were a range of disturbances of cranial nerve V.

CONCLUSIONS

The surgical approach varies based on the tumor conformation. However, a 2-stage pterional subtemporal and semisitting retrosigmoid approach is a safe, practical, and effective strategy for the removal of dumbbell-shaped trigeminal schwannoma in a pediatric patient.

Sinonasal Symptom Outcomes following Endoscopic Anterior Cranial Base Surgery in the Pediatric Population

Objective This study aimed to evaluate the impact of endoscopic anterior cranial base (ACB) surgery on sinonasal symptoms in the pediatric population utilizing the Sino-Nasal Outcome Test (SNOT)-22 questionnaire.

Design This is a retrospective review.

Setting The study was conducted at a tertiary academic medical center.

Participants Thirty-four consecutive patients, age 6 to 17 years, M:F 14:20, who underwent endoscopic ACB surgery from July 2008 to August 2019. Ten patients had baseline and a minimum of two subsequent postoperative SNOT-22 questionnaires available for analysis.

Main Outcome Measures Baseline and postoperative SNOT-22 scores were compared. The mean change from baseline sinonasal symptom scores in the pediatric and historical adult cohorts was compared.

Results The mean baseline SNOT-22 score for our 10 patient cohort was 0.46 out of 5 for each of the first 10 sinonasal-specific questions. This worsened to 1.69 at 1 month and returned to near baseline, 0.7, at 3 months postoperatively. The mean quality-of-life score improved to 0.91 at 1 month and 0.6 at 3 months postoperatively. The mean change from baseline for the following items: need to blow nose, runny nose, postnasal discharge, thick nasal discharge, wake up at night, reduced concentration, and frustrated/restless/irritable were similar to those in our historical adult cohort at 3 months postoperatively.

Conclusion Endoscopic ACB surgery in the pediatric population results in increased sinonasal symptom morbidity in the early postoperative period; however, symptoms return to near baseline by ∼3 months, and quality-of-life scores progressively improve in the postoperative period. These trends were similar to those seen in our historic adult cohort.

Association of meningitis and clival canal defect: case illustration, management, and systematic review of the literature

OBJECTIVE

Improper embryological development of the clivus, a bony structure that comprises part of the skull base, can lead to a clival canal defect. Previously thought to be a benign condition, clival canals have been reported to be associated with meningitis and meningoceles. In this review, the authors sought to present an unpublished case of a patient with a clival canal defect associated with meningitis and to evaluate all other reported cases.

METHODS

In October 2020, a search of PubMed, Web of Science, and Scopus was conducted to identify all cases of clival canals reported from January 1, 1980, through October 31, 2020.

RESULTS

Including the case presented herein, 13 cases of clival canals, 11 in children (84.6%) and 2 in adults (15.4%), have been identified. Of the pediatric patients, 5 (45.5%) had an associated meningocele, and 8 (72.7%) had meningitis. Nine of the 13 patients (69.2%) had defects that were treated surgically, 5 (38.5%) by a transnasal approach and 4 (30.8%) by a transoral approach. Two patients (15.4%) were treated with drainage and antibiotics, 1 patient (7.7%) was treated solely with antibiotics, and 1 patient (7.7%) was not treated. In the literature review, 8 reports of clival canals were found to be associated with meningitis, further contributing to the notion that the clival canal may be an overlooked source of recurrent infection. In several of these cases, surgical repair of the lesion was curative, thus preventing continued episodes of meningitis.

CONCLUSIONS

When a patient has recurrent meningitis with no clear cause, taking a closer look at clival anatomy is recommended. In addition, if a clival canal defect has been identified, surgical repair should be considered a safe and effective primary treatment option.

Outcomes in Pediatric Endoscopic Skull Base Surgery: A Systematic Review

Objectives  The frequency of endoscopic skull base surgery in pediatric patients is increasing. This study aims to systematically review the literature for endoscopic skull base surgery outcomes in children/adolescents aged 0 to 18 years. Design  A systematic review of the literature was performed in PubMed and SCOPUS databases querying studies from 2000 to 2020 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Final inclusion criteria included: case series with more than 10 patients with pediatric patients aged ≤18 years, endoscopic or endoscopic-assisted skull base surgery, and outcomes reported. Setting  This study was conducted at a tertiary care medical center. Participants  Children/adolescents aged 0 to 18 years who underwent endoscopic skull base surgery were participated in this study. Main Outcome Measures  Patient demographics, pathology, reconstructive technique, intraoperative findings, intraoperative, and postoperative surgical complications were measured through this study. Results  Systematic literature search yielded 287 publications. Of these, 12 studies discussing a total of 399 patients aged 0 to 18 years met inclusion criteria for final analysis. Seven of the 12 studies discussed a single pathology. The most common pathology was a skull base defect causing cerebrospinal fluid (CSF) leak. The majority of skull base repairs were made with free tissue grafts. The most common postoperative complication was CSF leak ( n  = 40). Twelve cases of meningitis occurred postoperatively with two of these episodes resulting in death. Conclusion  Endoscopic skull base surgery has been performed recently in the pediatric population in a variety of disease states. Inconsistent individual-level data and reporting standards are present in existing studies posing challenges for comparative analysis. Standardized reporting will aid future reviews and meta-analysis for rare skull base pathology.

Imaging of Developmental Skull Base Abnormalities

The skull base is a critical structure in the craniofacial region, supporting the brain and vital facial structures in addition to serving as a passageway for important structures entering and exiting the cranial cavity. This paper will review and highlight some of the embryology, developmental anatomy, including ossification, and related abnormalities of the anterior, central and posterior skull base using illustrative cases and tables. Pathologies such as dermoids/epidermoids, cephaloceles, nasal gliomas, glioneuronal heterotopias, various notochordal remnants, persistent craniopharyngeal canal, teratomas, platybasia, basilar invagination, clival anomalies and Chiari malformations will be discussed. Developmental pearls and pitfalls will also be highlighted.

Pediatric Skull Base Tumors: A Management Challenge

Context

Skull base tumors are varied in children and are particularly challenging to pediatric neurosurgeons, with few papers in the literature describing the evolution, complications, and outcome. The authors evaluated long-term outcomes in children submitted to skull base tumor surgery and performed a literature review.

Aims

The aim of this study was to analyze surgical results, complications, and outcomes, on comparison with previous publications.

Materials and Methods

A retrospective analysis of children undergoing surgery at a single institution between 2000 and 2018 for lesions of the cranial base was carried out. In addition, a literature review was carried out describing a total of 115 children operated on for skull base tumors.

Statistical Analysis

Chi-squared and Fisher's exact tests were performed to compare the distribution of categorical variables and a nonparametric Mann-Whitney U test was used to perform intergroup comparisons of continuous variables.

Results

Seventeen children ranging in age from 8 months to 17 years (mean, 10.9 years) underwent skull base approaches. Tumor types included schwannoma, meningioma, chondroid chordoma, mature teratoma, epidermoid cyst, hemangiopericytoma, rhabdomyosarcoma, myofibroblastic inflammatory tumor, fibromyxoid sarcoma, Crooke's cell adenoma, ossifying fibroma, osteoblastoma, nasopharyngeal angiofibroma and Ewing's sarcoma. Gross total resection was achieved in 6 patients (35.3%), 12 patients (70.6%) had benign histology, and 5 patients (29.4%) had a malignant tumor. Transient postoperative cerebrospinal fluid leak affected only one patient. Thirteen children (76.4%) had a residual neurological deficit at last follow-up evaluation. Three (17.6%) surviving patients received adjuvant therapy. The rate of recurrence or lesion progression was 17.6%.

Conclusions

Skull base tumors in children present a therapeutic challenge because of their unique pathological composition and can lead to considerable morbidity and mortality in pediatric age.

Pediatric multicompartmental trigeminal schwannoma: illustrative case

BACKGROUND

Trigeminal schwannoma (TS) is an uncommon and histologically benign intracranial lesion that can involve any segment of the fifth cranial nerve. Given its often impressive size at diagnosis and frequent involvement of critical neurovascular structures of the skull base, it represents a challenging entity to treat. Pediatric TS is particularly rare and presents unique challenges. Similarly, tumors with extension into multiple compartments (e.g., middle cranial fossa, posterior cranial fossa, extracranial spaces) are notoriously difficult to treat surgically. Combined or staged surgical approaches are typically required to address them, with radiosurgical treatment as an adjunct.

OBSERVATIONS

The authors presented the unusual case of a 9-year-old boy with a large, recurrent multicompartmental TS involving Meckel’s cave, the cerebellopontine angle, and the infratemporal fossa. Near-total resection was achieved using a frontotemporal-orbitozygomatic craniotomy with a combined interdural and extradural approach.

LESSONS

The case report adds to the current literature on multicompartmental TSs in children and their management. The authors also provided a simplified classification of TS that can be generalized to other skull base tumors. Given a lack of precedent, the authors intended to add to the discussion regarding surgical management of these rare and challenging skull base lesions.

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.

Simulation of Pediatric Anterior Skull Base Anatomy Using a 3D Printed Model

OBJECTIVE

The pediatric skull base may present anatomic challenges to the skull base surgeon, including limited sphenoid pneumatization and a narrow nasal corridor. The rare nature of pediatric skull base pathology makes it difficult to gain experience with these anatomic challenges. The objective of this study was to create a 3-dimensionally (3D) printed model of the pediatric skull base and assess its potential as a training tool.

METHODS

Twenty-eight participants at various stages of training and practice were included in our study. They completed a pre- and postdissection questionnaire assessing challenges with endoscopic endonasal skeletonization of the carotid arteries and sella face using the 3D printed model.

RESULTS

The majority of participants had completed a skull base surgery fellowship (60.7%), were <5 years into practice (60.7%), and had <10 cases of pediatric skull base experience (82.1%). Anticipated challenges included limitation of maneuverability of instruments (71.4%), narrow nasal corridor and nonpneumatized bone (57.1%). On a scale of 0-10, 10 being very difficult, the average participant expected level of difficulty with visualization was 6.89 and expected level of difficulty with instrumentation was 7.3. On postdissection assessment, there was a nonstatistically significant change to 6.93 and 7.5, respectively. Participants endorsed on a scale of 0-10, 10 being very realistic, an overall model realism of 7.0 and haptic realism of 7.1.

CONCLUSIONS

A 3D printed model of the pediatric skull base may provide a realistic model to help participants gain experience with anatomic limitations characteristic of the pediatric anterior skull base.

Le Fort I Down-Fracture for Management of Midface Tumors

OBJECTIVE

To perform an integrative review associating current literature with a clinical series regarding the use of Le Fort I osteotomy for the removal of tumors located in the midface and central region of the skull base.

METHODS

A systematic review was performed through the PubMed, SCOPUS, and Cochrane databases. In addition, 4 different patients operated using the above-cited technique are described in this study.

RESULTS

Initially, 123 articles were found. After the removal of duplicates, and title and abstract reading, 27 articles were selected for data extraction. The Le Fort I surgical approach of tumors was performed in 183 patients.

CONCLUSION

The Le Fort I surgical approach allows lesion exeresis with good visualization, low rates of recurrences and complications, and without aesthetic compromises for the patient.

Pinning in pediatric neurosurgery: the modified rubber stopper technique

Head immobilization devices with skull pins are commonly used by neurosurgeons to stabilize the head for microsurgical techniques and to maintain accurate intraoperative neuronavigation. Pediatric patients, who may have open fontanelles, unfused sutures, and thin skulls, are vulnerable to complications during placement in pins. We review the various methods of pinning in pediatric neurosurgery and revisit the modified rubber stopper technique using a commonly available rubber stopper from a medication bottle over a standard adult pin of a Mayfield head clamp to prevent the pins from plunging through the thin pediatric skull.

Reconstruction of pediatric skull base defects: A retrospective analysis emphasizing the very young

INTRODUCTION

Pathology of the pediatric skull base is rare and ranges from congenital defects to malignancy and traumatic defects. Pediatric patients, particularly those ≤6 years of age, present a unique set of anatomic challenges for the skull base surgeon. The goal of this study was to retrospectively review our experience with reconstruction of pediatric skull base defects with particular emphasis on those ≤6 years of age.

METHODS

A retrospective chart review was conducted of patients ≤20 years of age who underwent endoscopic endonasal and combined endoscopic and open approaches to address cranial base pathology from 2007 to 2018. Patients were divided into two groups; those ≤6 years of age (group A) and those >6 years of age and ≤20 years of age (group B) and reconstructive techniques and outcomes were analyzed.

RESULTS

Intraoperative communication with the subarachnoid space (CSF leak) was created in 50% (3/6) of patients ≤ 6 years of age compared to 32.7% (16/49) in patients > 6 years and ≤20 years of age (P < 0.40) in management of their skull base disease. A vascularized flap was utilized for reconstruction in 66.7% (4/6) of patients ≤ 6 years of age and included a nasoseptal flap in 33.3% (2/6). A vascularized flap was utilized for reconstruction in 38.8% (19/49) of patients > 6 years and ≤20 years of age and most commonly included a nasoseptal flap (22.4%, 11/49). A lumbar drain was utilized in 50% (3/6) of patients ≤ 6 years of age compared to 18.4% (9/49) in patients > 6 and ≤20 years of age (P < 0.08). Post-operative CSF leaks were encountered in 16.7% (1/6) of patients ≤ 6 years of age compared to 10.2% (5/49) in patients > 6 and ≤20 years of age (P < 0.63). Behavioral issues were noted to potentially contribute to failed skull base reconstruction in patients <6 years of age.

CONCLUSIONS

Pediatric patients, particularly those ≤6 years of age, present a unique set of anatomic and behavioral challenges for the skull base surgeon as highlighted in this study.

Peel-Away Catheter Introducer Sheath for Reducing Nasal Traumatic Injury During Pediatric Endoscopic Skull Base Surgery

OBJECTIVE

Pediatric endoscopic endonasal surgery represents a still-growing discipline to approach complex skull base lesions and is characterized by unfavorable anatomical conditions. Children have very small nostrils and narrow rhinosinusal corridors, which could lead more easily to accidental injury to the nasal structures. We describe the use of a peel-away catheter introducer sheath as an innovative and minimally invasive technique to further reduce surgical trauma to the nasal mucosa and structures in pediatric rhinoneurosurgery.

METHODS

From January 2009 to December 2018, the peel-away sheath technique was used in 6 pediatric endoscopic procedures for biopsy and/or removal of skull base tumors.

RESULTS

The endoscopic technique with the use of the peel-away catheter allowed clear visualization of the surgical field during the whole course of the procedure and good surgical maneuverability. The use of the peel-away sheath did not prolong the surgical operation time and provided a good working channel. No intraoperative or postoperative major complications were observed. No nasal short-term complications were registered in all patients.

CONCLUSIONS

The use of a peel-away catheter introducer sheath technique represents a valid adjunct in the endoscopic pediatric skull base surgery repertoire. It can help in avoiding inadvertent surgical traumas to the sinonasal structures, especially by residents and junior surgeons. This could potentially reduce postoperative nasal morbidity.

Lack of Sphenoid Pneumatization Does Not Affect Endoscopic Endonasal Pediatric Skull Base Surgery Outcomes

OBJECTIVES/HYPOTHESIS

Currently, due to the rarity of pathology, there are limited data surrounding outcomes of pediatric skull base surgery. Traditionally, surgeons have proceeded with caution when electing endonasal endoscopic transsellar/transplanum approaches to the skull base in pediatric patients due to poor sphenoid pneumatization. In this study, we review outcomes of endoscopic pediatric skull base surgery based on sphenoid pneumatization patterns.

STUDY DESIGN

Retrospective chart review.

METHODS

A review of all cases of pediatric (age < 18 years) craniopharyngioma managed via an endoscopic endonasal approach at a tertiary academic medical center.

RESULTS

A total of 27 patients were included in the analysis. The median age was 8 years. Nineteen (70%) patients were male. Presellar, sellar/postsellar, and conchal sphenoid pneumatizations were found in 6, 11, and 10 patients, respectively. There was no significant association between sphenoid pneumatization pattern and extent of resection (gross vs. subtotal, P = .414), postoperative cerebrospinal fluid (CSF) leak (P = .450), intraoperative estimated blood loss (P = .098), total operative time (P = .540), and length of stay (P = .336). On multivariate analysis, after accounting for age, sex, preoperative cranial nerve involvement, and cavernous sinus invasion, there remained no significant association between sphenoid pneumatization pattern and extent of resection (P = .999) and postoperative CSF leak (P = .959).

CONCLUSIONS

Sphenoid pneumatization pattern does not appear to affect outcomes in endoscopic skull base surgery in the pediatric population. Importantly, lack of sphenoid pneumatization does not impede gross total resection or increase complications. Thorough knowledge of the anatomy during the endoscopic approach is critical to optimize outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:832-836, 2019.