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Complications of Percutaneous Lumbar Extraforaminotomy

Sang Chul Lee MD¹, Ricardo Ruiz-Lopez MD, FIPP², and Won Joong Kim MD³

¹ Seoul National University, Seoul, South Korea
² Clinica Vertebra, Spine and Pain Surgery Centers, Barcelona / Madrid, Spain
³ Pain and Rehabilitation Clinic, Fort Lee, NJ, USA

Introduction

Despite a paucity of studies examining the mechanical compression of nerve roots in lumbar foraminal spinal stenosis (LFSS), it has been assumed that LFSS results in damage to microvascular structures and continuous compression of nerve roots, subsequently causing ischemia, edema, demyelination, and C-fiber hyperactivation [1, 2]. One hypothesis of the physiopathology in LFSS is that numerous lumbar foraminal ligaments cause low back pain and radiculopathy [3, 4]. Lumbar foraminal ligaments fix the lumbosacral spinal nerves to the intervertebral foramen and protect the nerve and blood vessels from being damaged. However, if abnormal adhesion or too many foraminal ligaments exist, they may result in pain through compression of the nerve root [5]. To achieve effective decompression of LFSS by resecting foraminal ligaments, and to facilitate the spread of medication around the target nerve, specially designed instruments for percutaneous lumbar extraforaminotomy (PLEF) was invented to allow a minimally invasive procedure.

Anatomy

The boundaries of the foramen contain two mobile joints – intervertebral disc (IVD) and zygapophyseal joints. The boundaries are:

Roof: Inferior vertebral notch of the pedicle of the superior vertebra, ligamentum flavum at its outer free edge
Floor: Superior vertebral notch of the pedicle of the inferior vertebra, posterosuperior margin of the inferior vertebral body
Anterior wall: Posterior aspect of the adjacent vertebral bodies, the IVD, lateral expansion of the posterior longitudinal ligament, anterior longitudinal venous sinus
Posterior wall: Posteriorly bounded by the superior articular process (SAP) and inferior articular process (IAP) of the facet joint at the same level as the foramen, lateral prolongation of the ligamentum flavum
Medial wall: Dural sleeve
Lateral wall: Fascial sheet and overlying psoas muscle.

Structures in the intervertebral foramen are:

Spinal nerves (combined ventral and dorsal root in the root sheath)
Dural root sleeve, which becomes continuous with the epineurum of the spinal nerve at the distal end of the foramen
Lymphatic channels
Spinal branch of a segmental artery, which, after entering the foramen, divides into three branches to supply the posterior arch, neural, and intracanal structures and posterior part of the vertebral bodies
Communicating veins between internal and external vertebral venous plexuses
Two to four recurrent meningeal (sinuvertebral) nerves
Adipose tissue surrounding all the structures
Ligaments in the neural foramen.

Lumbar foraminal ligaments are composed of the following ligaments [6–8] (Figure 65.1):

Superior corporotransverse
Inferior corporotransverse
Superior transforaminal
Middle transforaminal
Inferior transforaminal.

**Figure 65.1** Schematic drawing of ligaments in the lumbar neural foramen. 1 = superior corporotransverse ligament; 2 = inferior corporotransverse ligament; 3 = superior transforaminal ligament; 4 = middle transforaminal ligament; 5 = inferior transforaminal ligament; 6 = posterior transforaminal ligament [9].

Indications

Lumbar radicular pain with or without low back pain
Herniated nucleus pulposus
Foraminal stenosis with or without central stenosis
Perineural fibrosis
Facet arthritis
Hypertrophy of the ligamentum flavum
Previous failure of conservative management (exercise therapy, physical therapy, analgesic medication, lumbar transforaminal epidural steroid injection, percutaneous epidural adhesiolysis etc.).

Contraindications

Local or systemic infection
Uncorrected coagulopathy
Allergies to local anesthetics or contrast dyes
Spondylolisthesis (relative)
Severe degenerative change (relative)
Patient refusal.

Technique

Percutaneous Extraforaminotomy (PLEF) provides advantages as a Minimally Invasive Spine Technique:

Soft-tissue impingment is common
Ligamentum flavum hypertrophy
Provides access to the epidural space, posterior, and anterior canal
It is a safe surgery under X-ray imaging
Complications in experienced hands are extremely rare.

There are two specially designed instruments to implement PLEF.

1) Instrument consisting of (Figures 65.2 and 65.3):

**Figure 65.2** Specially designed instruments for the percutaneous lumbar extraforaminotomy procedure [9].

**Figure 65.3** Disposable set for PLEF (Park®).

16G Tuohy needle
14G trocar
Cannula
End mill
Curette
Catheter.

After 8–10 ml of 0.5% lidocaine was administered at the intended needle entry tract, a 15 cm, 16G Tuohy needle is inserted under anteroposterior fluoroscopic guidance. In the lateral fluoroscopic view, the needle tip is advanced until it is located at the posterior part of the borderline between the IAP and SAP. An epidurogram is then obtained after injection of 5 ml contrast to confirm that the needle is placed in the epidural space and to avoid intravascular or subarachnoid needle placement. Then, the Tuohy needle is withdrawn slightly to the level of the facet joint capsule. Subsequently, a trocar is inserted adjacent to the Tuohy needle and the Touhy needle is removed. Next, a cannula is inserted through the trocar to guide an end mill, which ultimately replaces the trocar. Finally, the end mill is placed within the epidural space in the intervertebral foramen. In the next step, the end mill is removed and a curette is introduced through the cannula while maintaining the bevel of the curette facing to the ventral side to avoid any neurovascular injury (Figure 65.4a–d).