Uniportal Endoscopic Cervical Decompression For Myelopathic Spinal Stenosis

Summary

This article presents an endoscopic cervical decompression technique enabling precise, minimally invasive treatment of myelopathic spinal stenosis with effective neural decompression and reduced tissue damage.

Abstract

This article demonstrates the step-by-step surgical technique of endoscopic cervical decompression for myelopathic cervical spinal stenosis. The procedure allows precise neural decompression under continuous endoscopic visualization while minimizing muscle disruption and aiming to preserve posterior stabilizing structures. The key steps include portal docking, controlled drilling of the osseous structures, and removal of the ligamentum flavum to achieve sufficient spinal cord decompression while avoiding neural injury. Despite its minimally invasive advantages, endoscopic cervical decompression can be technically challenging, particularly for surgeons in the early learning phase, due to the narrow working corridor and close proximity to critical neural elements. Therefore, this video article provides detailed visual guidance and explanations of common technical difficulties, anatomical considerations, and practical strategies to overcome these challenges. By highlighting both procedural steps and potential pitfalls, this protocol demonstrates the feasibility of endoscopic cervical decompression and presents representative institutional outcomes. It aims to facilitate safer and more effective adoption of this minimally invasive treatment option for cervical myelopathy in appropriately selected patients.

Introduction

Approximately 5–20% of patients with cervical spinal stenosis eventually require surgical intervention due to progressive myelopathic symptoms^1,2. Conventional wide posterior decompression through open laminectomy provides sufficient neural decompression; however, it is associated with extensive injury to the posterior musculature and supporting soft tissues³. Such tissue disruption has been reported to contribute to postoperative cervical kyphotic deformity and segmental instability. To mitigate these deformities, posterior instrumentation with screw fixation has been employed in selected cases. Although effective in maintaining sagittal alignment, this approach may restrict postoperative cervical motion and has been associated with complications, including hardware-related failure⁴.

To overcome these limitations, minimally invasive spine surgery techniques aimed at minimizing muscle and soft tissue injury have increasingly been applied to the cervical spine⁵. Among these, endoscopic cervical decompression has gained attention due to its ability to achieve adequate neural decompression while minimizing surgical invasiveness⁶. By preserving posterior stabilizing structures, this technique may reduce the risk of postoperative deformity and facilitate earlier functional recovery⁷. Nevertheless, because the procedure is performed in close proximity to the spinal cord within a narrow working corridor, it carries a non-negligible risk of complications and requires a steep learning curve, particularly for surgeons in the early phase of adoption⁸.

The overall goal of this method is to achieve effective spinal cord decompression while minimizing tissue injury and preserving cervical stability. In this article, we provide a detailed, step-by-step demonstration of endoscopic posterior cervical decompression, with a specific focus on anticipated technical challenges, anatomical pitfalls, and practical strategies to enhance procedural safety. This technique may be particularly suitable for patients with posterior compressive pathology, including multilevel cervical myelopathy or selected cases without significant cervical deformity. This article presents a technical protocol supported by representative institutional outcomes rather than comparative efficacy data. Representative preoperative and postoperative imaging, radiological findings, and clinical outcomes from patients treated at our institution are presented to assist readers in determining whether this technique is an appropriate surgical option for the management of myelopathic cervical spinal stenosis.

Protocol

The procedure described in this article was approved by the Institutional Review Board (IRB No. HRS-IRB 2025-001), and written informed consent was obtained from all patients for participation, video recording, and data collection.

1. Experimental preoperative preparation

1. Patient selection
   NOTE: The primary indication for this procedure is multilevel degenerative cervical myelopathy with predominantly posterior compressive pathology.
   1. Select patients presenting with clinical signs and symptoms of cervical myelopathy, including gait disturbance, hand clumsiness, or upper motor neuron signs.
   2. Confirm spinal cord compression at the target cervical level using preoperative magnetic resonance imaging (MRI) and computed tomography (CT).
   3. Ensure that the compressive pathology is primarily posterior or dorsal in nature and amenable to posterior endoscopic decompression.
      NOTE: Exclude patients with significant cervical deformity, defined as preoperative kyphotic alignment exceeding 10° in the C2–7 Cobb angle on lateral radiographs (e.g., swan-neck deformity), preoperative cervical instability, or conditions requiring mandatory anterior decompression. This includes patients with predominant ventral pathology such as large cervical disc herniations or ossification of the posterior longitudinal ligament (OPLL), where adequate decompression cannot be achieved through a posterior endoscopic approach alone.
2. Patient preparation
   1. Perform routine preoperative evaluations, including standard laboratory blood tests and chest radiography, to confirm the patient's suitability for general anesthesia and surgical intervention.
   2. Conduct a thorough preoperative neurological examination to document baseline neurological status, including motor strength, sensory function, and signs of myelopathy.
   3. Administer prophylactic antibiotics (First-generation cephalosporin) on the day of surgery, typically initiated preoperatively and continued at regular intervals postoperatively according to institutional protocol.
3. Equipment
   1. Ensure the availability of a full-endoscopic spine surgery system, including an endoscope with an integrated working channel, light source, irrigation system, and high-definition video display.
      NOTE: The principles and techniques described in this protocol are generally applicable to most contemporary spinal endoscopic systems.
   2. Ensure that standard endoscopic spine surgery instruments (Table of Materials) are available, including working cannulas, sequential dilators, radiofrequency (RF) probes for soft tissue ablation and hemostasis, endoscopic forceps, Kerrison punches, and a high-speed endoscopic drill with diamond and cutting burr.

2. Surgical preparation

1. Anesthesia
   1. Evaluate the patient's operative risk using the American Society of Anesthesiologists (ASA) Physical Status Classification.
   2. Establish at least one large-bore peripheral intravenous line (14 G or 16 G).
   3. Continuously monitor electrocardiography, blood pressure using an automated cuff, pulse oximetry, urine output, and body temperature.
   4. Administer sedative agents and neuromuscular blockers, and perform endotracheal intubation to secure the airway under general anesthesia.
   5. Upon completion of the procedure, reverse anesthesia.
   6. Intraoperative neuromonitoring (e.g., somatosensory evoked potentials and motor evoked potentials) may be used when available to enhance procedural safety. In our institution, neuromonitoring is not routinely utilized, and careful surgical technique is employed to avoid direct spinal cord manipulation.
2. Operation setting (Figure 1)
   1. Position the surgeon at the operating side of the patient, directly facing the endoscopic monitor, to maintain ergonomic instrument handling and a direct line of sight to the surgical field.
   2. Assign a scrub nurse to stand adjacent to the surgeon, responsible for managing endoscopic instruments, RF probes, drills, and other devices while assisting instrument exchange as required during the procedure.
   3. Have the anesthesiologist stand at the head of the patient to allow continuous airway access and physiologic monitoring throughout the procedure.
   4. Arrange the C-arm fluoroscopy unit perpendicular to the operating table to allow unobstructed anteroposterior and lateral imaging during localization and intraoperative confirmation.
   5. Place the endoscopic video tower and image processing system opposite the surgeon, within the surgeon's direct visual axis, to optimize hand–eye coordination.
3. Patient positioning and surgical draping (Figure 2)
   1. Place the patient in the prone position on a radiolucent operating table equipped with a Wilson frame, with the neck maintained in slight flexion and a mild reverse Trendelenburg position to facilitate venous drainage and optimize posterior cervical exposure.
   2. Immobilize the patient using a three-point plaster traction technique applied to the head, shoulders, and back to maintain stable cervical alignment throughout the procedure.
   3. Apply polyurethane foam pads to protect pressure-sensitive areas, including the eyes, nose, and mouth, in order to prevent pressure-related injuries.
   4. Secure the patient to the operating table with wide safety straps, ensuring adequate padding of all bony prominences.
   5. Perform sterile skin preparation of the posterior cervical region using iodine povacrylex and isopropyl alcohol, followed by sterile draping to allow unobstructed access for endoscopic instrumentation and fluoroscopic guidance.

3. Surface marking and docking (Figure 3)⁹

1. Perform skin marking under anteroposterior and lateral cervical fluoroscopic guidance, targeting the junction of the lateral margin of the interlaminar space and the medial border of the facet joint (V point) (Figure 3A,B).
2. Make a longitudinal skin incision approximately 1 cm in length at the marked V point.
3. For a single-level decompression, center the incision directly over the V point of the target level.
4. For two-level decompression, perform a single skin incision and achieve endoscopic access by cranial-caudal sliding of the working channel. In this case, center the incision at the midpoint between the V points of the two target levels.
5. For three-level decompression, perform a single skin incision, with the incision centered over the V point of the middle level to allow adequate cranial and caudal reach.
   NOTE: During multilevel decompression, excessive angulation of the endoscope should be avoided to prevent undue soft tissue tension. Controlled cranial-caudal sliding of the working channel along the bony corridor is recommended. If adequate access cannot be achieved without excessive tissue strain, repositioning or an additional skin incision should be considered.
6. Insert the obturator and working sleeve sequentially and dock them onto the target bony landmark (Figure 3C,D).
   NOTE: During obturator and working sleeve insertion, advance strictly along the intended bony corridor to avoid unnecessary violation of paraspinal muscles and vessels.
7. Reconfirm the final position of the working sleeve tip using anteroposterior and lateral fluoroscopy.

4. Endoscopic decompression

NOTE: This section describes the fundamental steps of endoscopic posterior cervical decompression. During surgery, the water pump pressure is maintained at 30–50 mmHg. Care should be taken to maintain appropriate irrigation pressure and ensure continuous fluid outflow to avoid excessive pressure accumulation. Close intraoperative observation is recommended throughout the procedure. For multilevel procedures, the same sequence is repeated at each level, and the workflow is illustrated schematically in the accompanying figures for a two-level decompression (Figure 4).

1. Bone drilling (Laminectomy)
   1. Remove the muscle fibers covering the V point using a combination of radiofrequency ablation and blunt dissection until the bony anatomy of the superior articular process (SAP) and inferior articular process (IAP) is clearly visualized.
   2. Drill the medial-inferior portion of the IAP to expose the medial-superior portion of the SAP (Figure 4A).
      NOTE: This step typically extends approximately 3–4 mm lateral to the initially identified V point and represents a fundamental requirement for securing an adequate lateral working margin.
   3. Follow the exposed SAP medially to identify the cranial portion of the caudal lamina.
      NOTE: Bleeding from the facet joint after drilling is controlled using RF ablation in coagulation mode. Persistent cancellous bone oozing is managed by additional drilling to mechanically tamponade the bleeding surface.
   4. Drill the caudal lamina medially and caudally to expose the inferior edge of the ligamentum flavum and the midline raphe.
   5. Drill the caudal portion of the cranial lamina similarly to expose the superior edge of the ligamentum flavum, extending decompression toward the midline and contralateral side until the medial aspect of the contralateral superior articular process (facet joint) is visualized, which serves as the anatomical endpoint (Figure 4B).
      NOTE: Although sublaminar drilling may be performed when crossing to the contralateral side, if there is a risk of spinal cord compression, controlled undercutting and limited additional bone drilling around the spinous process may be performed to secure a safer working corridor, while preserving the posterior tension band structures and avoiding complete detachment of the spinous process (Figure 4A). In multilevel procedures, the same decompression strategy is applied sequentially at each level using a cranio-caudal sliding of the working channel through a single incision, maintaining a continuous laminar corridor.
2. Ligamentum flavum removal
   1. Carefully dissect the lateral margins of the ligamentum flavum.
      NOTE: Adequate bony decompression should be achieved through sufficient drilling before proceeding to ligamentum flavum manipulation.
   2. Remove the ligamentum flavum en bloc to expose the dura mater and spinal cord, and confirm bilateral lateral recess decompression (Figure 4B,C).
      NOTE: After ligamentum flavum removal, instruments such as punches should be used cautiously and only when direct visualization confirms that spinal cord contact is avoided.

5. Hemostasis and wound closure

1. Achieve hemostasis using radiofrequency coagulation under endoscopic visualization, targeting only clearly identified bleeding points.
2. Apply a gelatin-thrombin based flowable hemostatic agent (e.g., Floseal) to the epidural space and bony surfaces as needed to reinforce hemostasis.
3. Insert a closed-suction drainage catheter through the working incision to reduce the risk of postoperative hematoma formation.
4. Perform subcutaneous closure using absorbable surgical sutures.
5. Complete skin closure using a topical skin adhesive.

6. Postoperative management

1. Maintain closed-suction drainage following surgery. Here, place at least one drain per level and maintain drainage for approximately 2 days.
2. Remove the drainage catheter when the output is less than 50 mL over 24 h.
3. Monitor patients for neurological status, wound condition, and signs of postoperative complications.
4. Allow mobilization, oral intake, and basic daily activities as tolerated.
5. Discharge the patient once adequate pain control is achieved and independent ambulation and basic activities (e.g., eating, toileting) are possible, typically after drain removal.

Results

Between August 2023 and August 2024, 24 patients underwent uniportal endoscopic cervical decompression at our institution. All patients included in the representative series were consecutive cases treated during the study period. Outcome analysis was performed for patients who completed the predefined 1 year follow-up duration, and no patients were excluded based on clinical outcomes. A total of 15 patients completed >12 months of follow-up (mean 15.2 ± 2.5 months, range 12.0–18.1 months). Around 6 patients had >1 ...

Discussion

Endoscopic posterior cervical decompression is often perceived as one of the most challenging endoscopic spine procedures, requiring a steep learning curve and advanced technical proficiency⁸. These challenges frequently result in incomplete decompression or increased complication risk during the early adoption phase¹⁰. The present protocol aims to address these difficulties by highlighting critical steps and practical strategies for safe and effective decompression. These ...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
10K Arthroscope tube set	Conmed	10k100	Irrigation system console
10K Irrigation console	Conmed	10k	Irrigation system console
1-Coarse Diamond Bur SPL (4.5)	Nakanishi	PDS-1CD330-35	High-speed drill
32-inch LCD monitor	Karl Storz	EX3220-3D	Monitor
Biopsy Forceps, Blakesley	JOIMAX	BFS323061	WL 320 mm / OD 3.5 mm / JL 6.0 mm
Biopsy Forceps, Spoon	JOIMAX	THF322541	WL 320 mm / OD 2.5 mm / JL 4.0 mm
Biopsy Forceps, Spoon, angled	JOIMAX	THF322041	WL 320 mm / OD 2.0 mm / JL 4.0 mm / 45°
C-arm fluoroscopy	GEMSS Healthcare	KMC-650
Chloraprep(2% CHG, 70% IPA)	GEMSS Healthcare		Skin preparation material, 26 mL
Closed-suction drain	Moohan co,	M-VAC	100 mL
Delphi plus	CNS Medical	DP410-90-280	Radiofrequency probe
Endo-Kerrison-Pistol Handle	JOIMAX	EKH550000	OD 5.5 mm
Endo-Kerrison-Shaft	JOIMAX	EKS24551540	WL 240 mm / OD 5.5 mm / F 1.5 mm / 40°
Endo-Kerrison-Shaft	JOIMAX	EKS24553040	WL 240 mm / OD 5.5 mm / F 3.0 mm / 40°
Floseal Hemostatic Matrix	Baxter	5 mL Kit	Hemostatic agent
Grasper Forceps	JOIMAX	THG323555	WL 320 mm / OD 3.5 mm / JL 5.5 mm
Guiding Rod, conical	JOIMAX	GRD226315	L 225 mm / OD 6.3 mm
Guiding Tube, conical, red	JOIMAX	GTC177010	L 165 mm / ID 7 mm / OD 10 mm
Guiding Tube, conical, violet	JOIMAX	GTC151510	L 175 mm / ID 10 mm / OD 15 mm
Image 1S Video System	Karl Storz	N/A	Console and camera system
Laminoscope	JOIMAX	LS1006125O	WL 125 mm / OD 10.0 mm / 15° / WChD 6.0 mm / 2x IC 2.0 mm
Nerve Hook	JOIMAX	TNH322533	L 320 mm / OD 2.5 mm / JL 3.3 mm
Primado2 Drill System	Nakanishi	P200-CU-100	High-speed drill
Primado2 Foot Controler	Nakanishi	FC-73	High-speed drill
Primado2 Slim motor handpiece	Nakanishi	P200-SMH-HS	High-speed drill
Safety straps/Padding-related setup	JU medics		Face sponge, Leg straps
Semi-Flexible Grasper Forceps, curved, up-biting	JOIMAX	TFG322522U	WL 320 mm / OD 2.5 mm / Helix
Skin Adhesive Exofin	Chemence Medical		1 mL
Super Slim attachment 200	Nakanishi	P200-RA330	High-speed drill
Surgi-Max Air	Elliquence	IEC4-SP	Radiofrequency probe
Trigger-Flex	Elliquence	DTF-40	Radiofrequency probe
Vicryl	Ethicon		Absorbable sutures, size 3-0
Wilson frame	Mizuho OSI		Radiolucent