Dorsal Root Ganglion Pulsed Radiofrequency Lesioning

Chapter 7 Dorsal Root Ganglion Pulsed Radiofrequency Lesioning

Conventional heat radiofrequency lesioning of the dorsal root ganglion (DRG) remains controversial owing to the potential risk of deafferentation pain. For this reason, DRG pulsed radiofrequency lesioning (PRFL), as a nondestructive neuromodulation technique, would be more attractive for chronic pain management [16]. Although the results of PRFL for neuropathic pain are anecdotal, the technique can be used as a potential treatment for chronic neuropathic pain [57]. There are two theories of the mechanisms of PRFL. One theory is that the electric field coming from the large current density of the cannula tip activates sensory fibers in the DRG and the spinal neurons to which they relay. The other theory is that temporal heat during each pulse might be responsible for the therapeutic effect [3].

Treatment objectives

The main objectives of DRG PRFL are to treat chronic segmental spinal nerve pain [16], segmental neuropathic pain, such as postherpetic neuralgia [8,9], and cervicogenic headache [6,1012].

Preoperative preparation

History Taking and Physical Examination

When examining a patient to determine whether he/she may be a potential candidate for DRG PRFL, the physician should look for the signs and symptoms of one of the following three classes of pain: chronic segmental pain of spine origin, chronic segmental pain of non-spine origin, or cervicogenic headache.

The signs and symptoms of chronic segmental pain of spine origin are as follows [4,13,1821]:

The signs and symptoms of chronic segmental pain of non-spine origin are as follows:

The signs and symptoms of cervicogenic headache [10] are as follows:


Cervical Region

The anatomy of the cervical region that is relevant to DRG PRFL can be described as follows [12,2123]:

Thoracic Region

Most of the thoracic DRGs are located in the mid-cranial portions of the intervertebral foramina. Although the lateral margins of the thoracic DRGs are located in the extraforaminal portion, the medial margins of the DRGs are found in various locations (Table 7.1 and Fig. 7-3) [24,25].

Table 7.1 Localization of Boundaries of Dorsal Root Ganglia in the Intervertebral Foramina

Direction Localization
Anteroposterior DRG Anterior DRG Posterior
Anterior 1/3 5 (11%)
Middle 1/3 41 (89%) 4 (9%)
Posterior 1/3 42 (91%)
Posterior wall
Total 46 (100%) 46 (100%)
Mediolateral DRG Medial DRG Lateral
Foraminal 27 (59%) 3 (7%)
Extraforaminal 19 (41%) 43 (93%)
Total 46 (100%) 46 (100%)
Craniocaudal DRG Cranial DRG Caudal
Cranial 1/3 42 (91%) 10 (22%)
Middle 1/3 4 (9%) 31 (67%)
Caudal 1/3 5 (11%)
Total 46 (100%) 46 (100%)

DRG, dorsal root ganglion.

From Stolker RJ, Vervest AC, Ramos LM, et al: Electrode positioning in thoracic percutaneous partial rhizotomy: An anatomical study. Pain 1994;57:241-251.

The anatomy of the upper thoracic levels (T1-T8)—the shape of the lamina, and the narrow space between the rib and wide base of the transverse process—obstructs the passage of the cannula. This makes accurate positioning of a straight cannula for the DRG procedure impossible. However, use of a 2.5-cm curved needle (Fig. 7-4) makes obtaining an accurate positioning of the cannula possible [22]. Turning the curved needle without slightly withdrawing the needle may cause tissue trauma from rotation of the curved needle-tip. To change its direction, the needle should be turned while being withdrawn slightly and then advanced.

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Aug 5, 2016 | Posted by in NEUROSURGERY | Comments Off on Dorsal Root Ganglion Pulsed Radiofrequency Lesioning

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