Posterior Approach for Microsurgical Resection of a Ventrolateral Cervical Ganglioneuroma: an Illustrative Case and Technical Report

Summary

This protocol describes posterior midline cervical laminectomy with laminoplasty reconstruction and microsurgical resection of a ventrolateral intradural extramedullary ganglioneuroma in a pediatric patient, providing a reproducible surgical framework for this rare tumor.

Abstract

Ganglioneuromas of the cervical spine are exceptionally rare, well-differentiated neuroblastic tumors. We present the case of a 4-year-old female with a several-month history of progressive fatigue, right upper extremity weakness, and gait instability, in whom MRI demonstrated a homogeneously enhancing, cervical intradural extramedullary mass causing significant ventral spinal cord compression. A posterior midline approach with cervical two to cervical six laminoplasty was performed under continuous neurophysiological monitoring, providing wide dorsal access to the lesion. Microsurgical resection of the ventrolateral mass was accomplished using careful arachnoid dissection and cerebrospinal fluid drainage to achieve gross total resection, with histopathology confirming mature ganglioneuroma without malignant transformation. A postoperative MRI demonstrated gross total resection of the mass. At the 6-month follow-up, the patient has demonstrated marked neurological recovery, with full upper extremity strength and normal gait. This case offers a reproducible procedural framework for ventrolateral intradural cervical tumors in the pediatric population while underscoring the importance of multidisciplinary planning, laminoplasty-based posterior corridor selection, and meticulous microsurgical technique.

Introduction

Ganglioneuromas are well-differentiated, benign neuroblastic tumors arising from mature ganglion cells and Schwann cells of the sympathetic nervous system. They represent the most mature end of the neuroblastic tumor spectrum, which also includes neuroblastoma and ganglioneuroblastoma. Intraspinal ganglioneuromas are rare, accounting for fewer than 1% of all spinal tumors, and cervical involvement is exceptionally uncommon. Most reported cases occur in adults, making the pediatric presentation described here particularly unusual^1,2.

The goal of the present method is to demonstrate a reproducible posterior midline approach employing multilevel cervical laminoplasty for the safe microsurgical resection of an intradural extramedullary (IDEM) cervical ganglioneuroma with foraminal extension in a pediatric patient. For tumors with this morphology, in which the dominant mass is ventrolateral rather than purely ventral, a posterior approach provides direct access to the tumor's largest component without requiring anterior instrumentation or the added risks of an anterior corridor, including dysphagia, recurrent laryngeal nerve injury, and vertebral artery exposure. Compared with anterior cervical approaches, the primary advantage of this technique is that the posterior corridor allows exposure of the entire dorsal cervical spinal canal^3,4,5. The en bloc laminectomy with posterior tension band reconstruction described here aims to preserve spinal biomechanical integrity and potentially reduce the long-term risk of progressive kyphotic deformity in a growing child³. This technique may be applicable to other IDEM cervical tumors, including schwannomas and neurofibromas, and the stepwise framework is intended to assist neurosurgeons in planning and executing complex cervical tumor resections.

Protocol

This protocol follows the Institutional Review Board guidelines of Dell Children's Medical Center and complies with the principles of the Declaration of Helsinki. Informed consent was obtained from the patient's parents for publication of this case.

1. Preoperative planning and multidisciplinary evaluation

1. Document a detailed history and baseline neurological examination.
2. Obtain high-resolution magnetic resonance imaging (MRI) of the entire spine with and without gadolinium contrast to characterize the tumor's signal characteristics, extent of involvement, and degree of spinal cord compression.
3. Obtain a dedicated computed tomography (CT) of the spine to assess bony anatomy and help inform the surgical approach. Consider obtaining a CT angiography (CTA) of the neck to characterize the vertebral artery's position, caliber, and dominance relative to the tumor.
4. Convene a multidisciplinary tumor board including pediatric neurosurgery, pediatric neuro-oncology, neuroradiology, and neuropathology to review imaging and establish operative indications and goals.
5. Brief with the surgical team to prepare requisite instrumentation and surgical adjuncts, including the surgical technician, circulating nurse, anesthesia team, medical device representatives, and neuromonitoring team.

2. Anesthesia, intraoperative neurophysiological monitoring, and positioning

1. Induce general endotracheal anesthesia using a total intravenous anesthesia technique to permit reliable motor evoked potential (MEP) acquisition. Utilize propofol (100–200 µg/kg/min) and remifentanil (0.1–0.5 µg/kg/min) infusions. Avoid long-acting neuromuscular blocking agents after intubation.
2. Have the neuromonitoring team place subdermal needle electrodes for bilateral upper and lower extremity somatosensory evoked potential (SSEP) and MEP. Record baseline waveforms. MEP stimulation parameters: train of 5–7 stimuli, interstimulus interval 2–4 ms, stimulus intensity 100–200 V.
3. Record baseline waveforms and define alarm criteria as a greater than 50% reduction in MEP amplitude or greater than 10% prolongation of SSEP latency from baseline. Note that in cases of severe preoperative myelopathy, right-sided baseline signals may be absent; document this explicitly and monitor the contralateral intact signals as the primary reference.
   NOTE: D-wave recordings may also be considered for spinal cord monitoring, although they were not used in the present case.
4. Place the patient in the prone position on a Jackson table with the head secured in a Mayfield three-point skull clamp. Flex the neck to open the posterior interlaminar spaces. Confirm that the neck is in adequate alignment. Recheck MEP and SSEP signals.
5. Administer intravenous dexamethasone (4 mg) and cefazolin (100 mg/kg) prior to skin incision. Maintain mean arterial pressure (MAP) above 80 mmHg throughout the procedure to optimize spinal cord perfusion.

3. Posterior midline exposure, C2–C6 en bloc laminectomy and laminoplasty reconstruction

1. Make a posterior midline skin incision. Carry the dissection through the subcutaneous tissue and nuchal fascia to the spinous processes using electrocautery. Perform subperiosteal dissection of the paraspinal musculature from the spinous processes and laminae bilaterally from C2 to C6 while preserving the facet capsules.
2. Perform en bloc C2–C6 laminectomy using an ultrasonic bone knife to create bilateral parasagittal osteotomies at the lamina-lateral mass junction, minimizing bone loss.
   NOTE: The removed lamina is saved for reimplantation (laminoplasty), which is described in Section 6.
3. Elevate the entire laminar complex as a single unit and place it in moist saline-soaked gauze for later reimplantation. Following a laminectomy, perform an intraoperative ultrasound to confirm the presence and location of the intradural mass, characterize cord displacement, and verify the adequacy of bony decompression.
4. Achieve epidural hemostasis using bipolar electrocautery and thrombin-soaked pledgets. Inspect the epidural space for any extradural tumor extension.

4. Intradural exposure

1. Under high-power operative microscope magnification, open the dura in the midline using a 15-blade scalpel, then extend the durotomy rostrally and caudally with microscissors. Tack up the dural edges to the paraspinal musculature with 4-0 sutures to maximize the operative field.
2. Incise the posterior arachnoid layer sharply in the midline using microscissors. Release at least 10 mL of cerebrospinal fluid (CSF) after opening the arachnoid layer to achieve spinal cord relaxation.
   NOTE: Although not used in the present case, lumbar drain placement may be considered for additional CSF drainage.
3. Identify the tumor and begin to develop a circumferential plane around the tumor capsule using sharp microsurgical dissection.

5. Microsurgical tumor resection

1. Coagulate the tumor capsule with bipolar electrocautery and open it sharply using microscissors. Send a specimen from the capsule contents for intraoperative frozen section pathological analysis to guide the extent of resection.
2. Perform internal debulking using Penfield dissectors and an ultrasonic aspirator at low amplitude to debulk the tumor progressively. As the central portion of the tumor is removed, observe progressive medialization and decompression of the thecal sac, which facilitates access to the tumor periphery.
3. After adequate internal debulking of the intradural component, address the foraminal tumor extension. Coagulate the foraminal component of the capsule and resect using microscissors. Avoid lateral drilling in the foramen to prevent inadvertent injury to the vertebral artery.
4. Prior to and during foraminal dissection, use intraoperative micro-Doppler to confirm the position of the vertebral artery and define safe dissection limits.
   NOTE: The vertebral artery is specifically at risk when working lateral to the medial wall of the foramen transversarium.
5. Perform final intraoperative ultrasound to assess the extent of resection, re-expansion of the spinal cord, and restoration of CSF spaces. Inspect the tumor bed under high-power microscopic magnification for residual tumor or bleeding.
6. Achieve hemostasis with gentle bipolar coagulation at low voltage and irrigate the intradural space with warm normal saline.

6. Dural closure and laminoplasty reconstruction

1. Perform a primary watertight dural closure using a running 4-0 braided nylon suture on a tapered needle in a non-locking fashion. Perform a Valsalva maneuver at 40 cmH₂O to confirm that the repair is watertight. Reinforce the dural closure with fibrin sealant.
2. Reposition the preserved C2–C6 laminar complex into anatomical alignment. Secure the laminar block bilaterally using titanium "dog-bone" miniplates (e.g., Stryker Lorenz 1.5 mm system) at the lateral mass junctions bilaterally.
3. Use 4 mm unicortical screws directed perpendicular to the lateral mass surface. Optionally confirm adequate fixation and anatomical laminar position on intraoperative fluoroscopy.
   NOTE: Intraoperative fluoroscopy should be minimized in children to avoid unnecessary radiation exposure to the patient.
4. Reapproximate the paraspinal musculature in layers over the reconstruction using interrupted sutures. Close the fascia in a watertight fashion.
5. Close the subcutaneous layer with buried sutures and the skin with a running absorbable suture. Apply a sterile occlusive dressing.

7. Postoperative care

1. Have the anesthesia team extubate the patient if appropriate and transfer to the pediatric intensive care unit (PICU). Augment the MAP to the upper end of age-adjusted normal parameters to optimize spinal cord perfusion.
2. Perform hourly neurological assessments for the first 12 h, documenting motor strength, sensation, and bladder function.
3. Administer intravenous dexamethasone with a 3-day taper. Begin formal physical and occupational therapy assessment on postoperative day 1. Target discharge home when the patient demonstrates safe mobility and adequate pain control.
4. Schedule outpatient follow-up at 2 weeks, 1 month, 6 months, and 1 year with repeat MRI at 6 months and 1 year to monitor for recurrence.

Results

This protocol was executed successfully in a 4-year-old female with a several-month history of progressive fatigue, right upper extremity weakness, and gait instability. Her strength exam was notable for right triceps, grip, and bilateral dorsiflexion and plantarflexion equal to 4/5 on the Medical Research Council (MRC) scale. Her MRI demonstrated a homogeneously enhancing, cervical intradural extramedullary mass causing significant ventral spinal cord compression (Figure 1). A posterior mid...

Discussion

This protocol and representative case offer a guide for a posterior approach to ventrolateral IDEM cervical tumors in the pediatric population, while underscoring the importance of multidisciplinary planning, laminoplasty-based selection of the posterior corridor, and meticulous microsurgical technique. Approach selection for IDEM cervical tumors must be guided by the tumor's dominant location on axial imaging. For tumors with a ventrolateral epicenter or foraminal extension (as in the present case), the posterior ap...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
BK Ultrasound	GE Healthcare	2300-61	Intraoperative ultrasound used to visualize lesion prior to and after resection
Mayfield Skull Clamp	Integra LifeSciences	A1114	Cranial fixation system for positioning patient
Operative Microscope	Leica	M530 OHX	Intraoperative microscope used for resection of lesion
Sonopet iQ	Stryker	5500-050-000	Ultrasound aspirator used for en bloc laminectomy and lesion debulking
Universal Neuro III	Stryker	53-34804	Titanium plates and screws used for laminoplasty