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 midline approach with C2–C6 en bloc laminectomy and laminoplasty reconstruction was performed under continuous neurophysiological monitoring, providing wide dorsal access to the lesion. Microsurgical resection of the ventral mass was accomplished using gravity-assisted cord relaxation with CSF drainage and careful arachnoid dissection. The dentate ligament did not require sectioning. The histopathology confirmed a mature ganglioneuroma without malignant transformation (Figure 2). Postoperative MRI confirmed gross total resection and decompression of the spinal cord (Figure 3). At 6-month follow-up, the patient has demonstrated marked neurological recovery and has 5/5 strength on the MRC scale in all extremities. She has returned to her normal activities, including running and playing soccer.

Figure 1: Preoperative MRI of the cervical spine with and without contrast. (A) Sagittal T2-weighted pre-contrast MRI, (B) sagittal T1-weighted post-contrast MRI, and (C) axial T2-weighted pre-contrast MRI demonstrate an enhancing intradural extramedullary dumbbell-shaped mass spanning C2–C5 with extension into the right C3-C4 neural foramen, causing severe spinal cord displacement and myelomalacia. Please click here to view a larger version of this figure.

Figure 2: Hematoxylin and eosin (H&E)-stained section of the resected tumor. The pathology at 20× magnification demonstrates mature ganglion cells embedded in a Schwannian stroma without neuroblastic components, consistent with ganglioneuroma. Please click here to view a larger version of this figure.

Figure 3: Postoperative MRI of the cervical spine with and without contrast. (A) Sagittal T2-weighted pre-contrast MRI, (B) sagittal T1-weighted post-contrast MRI, and (C) axial T2-weighted pre-contrast MRI demonstrate gross total resection of the neoplasm with decompression of the spinal cord. Please click here to view a larger version of this figure.

Category	Anterior	Posterior
Advantages	Direct access to the ventral tumor component	Wide exposure of the posterior canal
	Best visualization of the anterior dural attachment	Multilevel access is more easily obtained
	Supine position simplifies airway management	Direct access to the posterolateral and foraminal tumor
	Minimal muscle dissection may lead to less postoperative pain	Lower risk of postoperative dysphagia or recurrent laryngeal nerve injury
		Intraoperative ultrasound is more easily employed
Disadvantages	Limited access to posterior or lateral tumor components	Indirect access to ventral midline tumors
	Contiguous multilevel access requires corpectomy with reconstruction	May require cord mobilization for ventral access
	Risks include dysphagia, recurrent laryngeal nerve injury, vertebral artery, esophageal, and trachea injury	Postoperative pain from muscle dissection
		Risks include CSF leak, post-laminectomy kyphosis, and nerve palsy

Table 1: Comparison of surgical approaches for ventrolateral cervical intradural extramedullary tumors. The table outlines key advantages and disadvantages of the anterior and posterior surgical approaches for resection of a ventrolateral cervical intradural extramedullary tumor.

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 approach provides the most direct access with a lower risk of vascular and visceral injury. In contrast, purely ventral intradural tumors, particularly calcified meningiomas adherent to the anterior dura, may be better approached anteriorly or anterolaterally, where direct visualization avoids the need for cord displacement (Table 1).

Preoperative evaluation of such cases mandates high-resolution MRI of the cervical spine with and without gadolinium contrast, CTA of the cervical vasculature when foraminal or lateral extension is present, a multidisciplinary team discussion, and thorough informed consent with the family. Intraoperative neurophysiological monitoring (IONM) with MEPs and SSEPs is an important surgical adjunct that provides real-time feedback on spinal cord function⁶. Surgeons should be aware that in cases of severe preoperative myelopathy, baseline signals may be absent or markedly degraded on the affected side; in such cases, any recovery of signals during or after decompression may serve as a positive prognostic indicator, as in the index case. During exposure, it is critical to achieve a wide laminectomy to provide a sufficient posterior corridor. Once the dura has been opened, meticulous arachnoid dissection with progressive CSF release with or without lumbar drain (not used in the present case) is essential to achieve gravity-assisted cord relaxation and minimize mechanical retraction. For tumors with any ventral component, selective sectioning of the dentate ligaments (not performed in the present case) may be considered to increase cord mobility. During tumor resection, it is important to maintain continuous IONM surveillance⁶.

Surgeons may encounter some technical challenges when applying this technique. Bone loss during drilling of the en bloc laminectomy may lead to difficulty with reconstruction during the laminoplasty⁷. To minimize bone loss, an ultrasonic knife may be utilized for the laminectomy, as in this case. Previously treated or calcified tumors may have dense arachnoid adhesions between the tumor capsule and the pia mater. In such cases, subtotal resection with spinal cord decompression and surveillance may be considered. Postoperatively, the presence of the CSF leak may require surgical re-exploration. To minimize the risk of postoperative CSF leak, a watertight dural closure and verification with the Valsalva maneuver may be helpful. Moreover, adjunct dural sealants such as fibrin glue and sealant patch may be considered⁸.

One important limitation of the posterior approach is that it relies on a wide working corridor to resect the ventral tumor and decompress the spinal cord; in cases of severe ventral cord compression without adequate dorsal access, an anterior approach may need to be considered⁹.

The significance of this method lies in its applicability to the broader category of IDEM tumors, which together represent approximately 25% of all primary spinal cord tumors¹⁰. The en bloc laminectomy with posterior reconstruction described here is particularly valuable in the pediatric population, where laminectomy without reconstruction may carry the risk of post-laminectomy kyphosis. By replacing and securing the posterior laminar complex with titanium dog-bone plates and resuspending the posterior tension band, this technique aims to restore dynamic posterior stability and potentially reduce the likelihood of progressive deformity, a critical consideration in a growing child³.

In conclusion, this protocol provides a systematic, reproducible operative framework for the resection of ventral intradural cervical tumors via a posterior midline laminoplasty approach. The key principles of multidisciplinary planning, IONM-guided microsurgery, and posterior bony reconstruction are broadly applicable and have the potential to standardize surgical practice for this challenging subset of spinal tumors. Future studies with larger cohorts are needed to define long-term neurological outcomes, deformity rates, and recurrence data in pediatric patients treated with this technique.

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