The Anatomy of Dorsal Ramus Nerves and Its Implications in Lower Back Pain

Abstract

This article reviews the relationship between the spinal dorsal ramus system and low back pain, including the anatomy, clinical findings, pathogenesis and treatment of low back pain mediated by spinal dorsal ramus and zygapophysial (facet) joint syndrome. Each spinal dorsal ramus arises from the spinal nerve and then divides into a medial and lateral branch. The medial branch supplies the tissues from the midline to the zygapophysial joint line and innervates two to three adjacent zygapophysial joints and their related soft tissues. The lateral branch innervates the tissues lateral to the zygapophysial joint line. The clinical pain presentations follow these anatomic distributions, which can be used for localizing the involved dorsal ramus. The diagnosis can be confirmed by performing a single dorsal ramus block that results in relief of pain and muscle spasm. Etiologically, any factor that stimulates the spinal dorsal ramus can cause low back pain, which is distinct from zygapophysial joint syndrome. Clinically, L1 and L2 are the most common sites of dorsal rami involvement. Treatment includes spinal dorsal ramus injection therapy and percutaneous neurotomy. Summarily, irritation of the spinal dorsal ramus system is a potential source of low back pain. Based on the anatomy and clinical presentation, the involved spinal dorsal ramus can be localized and treated

Does Lumbar Dorsal Ramus Syndrome Have an Objective Clinical Basis?

“…In our sample, we found progression of electrodiagnostic abnormalities in some subjects over time, particularly in patients in the LDRS group, which suggests that a single electrodiagnostic examination alone, without other corroborating clinical evidence at the first visit, may not be sufficient to make a diagnosis of LDRS. We would take issue with the conclusions of Zhou et al [10] that the physical examination findings they described are as clear‐cut as their review implies. They presented no new evidence in which such distinctions were made in a prospective manner.…”

Posterior Branches of Lumbar Spinal Nerves - Part I: Anatomy and Functional Importance

“…Zwró co no uwa gę na ich funk cję i zna cze nie w diagno sty ce i w le cze niu do le gli wo ści bó lo wych dol ne go od cin ka krę go słu pa. Pod ra żnie nie ga łę zi tyl nych mo że być spo wo do wa ne przez nie pra wi dło wo ści w sta wach mię dzy krę go wych, tj. zmia ny zwy rod nie nio we, zła mania, pa to lo gie wię za deł lub to reb ki sta wo wej i czę sto jest przy czy ną prze wle kłe go bó lu od cin ka lę dźwio -we go okre śla ne go jak Ze spół Ga łę zi Tyl nej (Lum bar Dor sal Ra mus Syn dro me) [7,8]. Za zwy czaj jest on dia gno zo wa ny za po mo cą blo kad dia gno stycz nych i le czo ny za bie ga mi ma ło in wa zyj ny mi, tj.…”

“…Irritation of posterior branches of the lumbar spinal nerves may be caused by abnormalities of facet joints, i.e. degeneration, fractures, pathology of ligaments or the articular capsule, and frequently leads to chronic lower back pain referred to as Lumbar Dorsal Ramus Syndrome [7,8]. The syndrome is usually diagnosed using diagnostic blocks and treated with lowinvasive procedures, such as radiofrequency neu rotomy [8][9][10][11].…”

Cooled Versus Conventional Thermal Radiofrequency Neurotomy for the Treatment of Lumbar Facet–Mediated Pain

“…First, the anatomy of the medial branches in the lumbar spine is relatively consistent. Human cadaveric studies have revealed that the medial branches of the dorsal rami at segmental levels L1‐L4 assume a constant and similar course [15‐18]. Each nerve emerges from its intervertebral foramen and enters the posterior compartment of the spine by coursing around the neck of the superior articular process below the foramen.…”

“…The temperature could increase to 45.5°C when a 2‐cm active tip was used, which is high enough to cause spinal cord injury [25]. In addition, the lateral and intermediate branches of the dorsal ramus, which innervate the iliocostalis and longissimus muscles, are not far away [17]. Injury of those nerves may result in muscle weakness, which may potentially compromise stability of the lumbar spine and worsen the back pain.…”