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Complications of Epiduroscopic Procedures

Altan Şahin MD

Hacettepe University, School of Medicine, Ankara, Turkey

Introduction

Epiduroscopy is a minimally invasive technique for the diagnosis and management of spinal pathologic conditions. Epiduroscopic view provides direct visualization of the spinal pathology and interventional treatment can be achieved with this technique. The first endoscopic visualization of the spinal canal in human subjects was reported by Pool in 1937 and by 1942, he had examined 400 patients using this technique [1, 2]. Since then, the technique has improved with technologic advances and, usng a 1 mm thin flexible fiberoptic endoscope with up to 30 000 pixels, a sharper vision can be achieved. Additionally, with a second working channel, some interventions such as adhesiolysis and disc decompression are possible.

Epidural adhesions cause compression or restriction of the nerve roots and also enhance spinal stenosis. There are different techniques to open the fibrosis in the epidural space. However, epiduroscopic procedures make direct visualization of the fibrotic tissue and its relationship with the nerve roots possible.

Anatomy

The epidural space surrounds the spinal part of the dura and extends from the foramen magnum to the sacral hiatus. It contains the spinal nerve roots, the plexus of veins, small arteries, lymphatics and epidural fat (Figure 40.1).

The sacrum is a triangular bone formed by the fusion of five sacral vertebrae. The central canal of the vertebral column continues along the sacrum and ends at the 4th sacral foramina, as the sacral hiatus. The anatomic variations of this bone affect the procedures and surgery around this bone [4].

Equipment(Figures 40.3–40.6)

**Figure 40.3** Flexible fiberoptic camera endoscope.

**Figure 40.6** Advancement of the catheter with the introducer. (*Source*: Author’s archive.)

Epiduroscopy catheter: The catheter must have two working channels; one dedicated for the camera and the other one for the drainage of the irrigation saline in order not to increase the epidural pressure. This second channel can also be used to advance the Holmium laser probe or the forceps that may be needed during the course of the procedure.
Flexible fiberoptic endoscope: This camera is 0.9–1.2 mm thin, provides 10–30 K pixels, 40× magnification, 70° field of view and allows a light source and video endoscope connection.
Video-endoscopy tower
Holmium laser device: Delivers fiberoptic pulsed laser in a wavelength of 2140 nm with a maximum penetration of 0.4 mm. It is crucial to use a low penetration laser in order not to damage surrounding neural structures. This device enables soft-tissue ablation, gasification, coagulation, and dissection.

Indications

Diagnosis of the pathologic conditions in the epidural space
Epidural adhesiolysis in postlaminectomy syndrome [5]
Lumbar disc decompression (limited to central or para-central herniations)
Lumbar spinal stenosis
Spinal cord stimulator placement
Dorsal root ganglion radiofrequency (RF)
Sinu-vertebral nerve denervation for the discogenic pain.

Contraindications

Systemic and local infections
Bleeding tendency and coagulopathies
Large, sequestered, extruded disc herniation
Cauda equina syndrome
Congenital anomalies
High ICP
Pregnancy
Cerebrovascular disease
Renal or liver insufficiency
Inflammatory or dystrophic skin lesions in the area of the sacral canal
Meningeal cysts, meningoceles, and meningomyeloceles
Severe respiratory insufficiency
Evidence of serious psychological disturbance
Persistent headaches
Cervical stenosis with myelopathy
Patient refusal.

Technique

A meticulous preoperative assesment is essential before all minimally invasive procedures including complete blood count, coagulation tests, and lumbosacral MRI (end-level of the dural sac). The procedure should be performed in the operating theater under a surgical setup in order to avoid infectious complications. A pillow is placed under the inguinal area of the patient to facilitate placement of the catheter. The insertion of the catheter can be performed with three different techniques.

Seldinger technique: After anesthetizing the needle path, a 16G needle is introduced to the sacral hiatus, avoiding advancement to the end of the dural sac, under flouroscopic guidance. After penetrating the superficial posterior sacro-coccygeal ligament, a guidewire is introduced and the advancement in the epidural space is confirmed with lateral flouroscopic view. An appropriate catheter or a sheath introducer matching the size of the catheter is introduced through the guidewire. The epiduroscopy catheter is meticulously advanced in the sacral epidural space either anteriorly or posteriorly, according to the aim target of the procedure.
Introducer technique: After anesthetizing the introducer path, a 5 mm incision is made under the sacral hiatus and the introducer is advanced no further than the S3 level where the dural sac ends in most of the population. A guidewire is introduced to confirm that the tip is in the epidural space under lateral fluoroscopic guidance. The epiduroscopy catheter is inserted through the introducer and advanced to the sacral epidural space anteriorly or posteriorly, according to the aim target of the procedure (Figure 40.7).

Figure 40.7 Adhesions in the epidural space. (Source: Author’ archive.)
Transforaminal technique: Transforaminal epiduroscopic laser ablation (TELA) was recently developed to inspect the epidural space and deliver therapeutic devices such as lasers or forceps, which can selectively eliminate or modulate pathologies. While percutaneous laser disc decompression removes the center of the nucleus pulposus under fluoroscopic view, TELA ablates the herniated part of the nucleus pulposus under epiduroscopic vision [6]. This technique has been reported as beneficial in patients with failed back surgery syndrome with radicular pain [7].

In both techniques, the rest of the procedure is similar. First, an epidurogram is performed to confirm the tip of the catheter, to visualize the filling defects before adhesiolysis and to visualize the herniation before disc decompression.

Epidural Adhesiolysis

The aim of this procedure is to release the fibrotic tissue surrounding the neural structures to relieve pain caused by stretching or compressing the roots. This can be achieved by:

Manipulating the catheter to release the adhered scar tissue (Figure 40.8)

Figure 40.8 Shrinkage of the disc and release of the edematous root. (Source: Author’s archive.)
Chemical adhesiolysis with hyaluronidase or hypertonic saline
Baloon adhesiolysis with a special catheter with an inflatable tip
RF adhesiolysis with a flexible RF probe [8]
Laser adhesiolysis with a Ho-YAG laser.

The procedure can be performed in both the anterior and posterior epidural space. However, the surgical operations’ target (i.e., the disc) and the roots are anatomically closer to the ventral epidural space.

Trans-sacral Epiduroscopic Disc Decompression (SELD)

The aim of this procedure is to decompress the central or paracentral protrusions of the nucleus pulposus. An anterior approach and the introducer technique is more appropriate to reach the target. After placing the introducer, the tip of the catheter is flexed slightly anteriorly in the sacral epidural space. After reaching the desired disc level, the roots are visualized and the Ho-YAG laser probe is penetrated to the posterior longitudinal ligament. After a test shoot without an involuntary twitch on the legs, the laser decompression is initiated (Figure 40.9). The operator can observe the shrinkage of the disc and the roots relationship with it. It is also possible to extract the disc with a forceps (Figure 40.10).