Anatomical Observation and Clinical Significance of the Medial Branch of the Lumbar Dorsal Rami.

STUDY DESIGN: Anatomical study. OBJECTIVE: This study aimed to elaborate on the anatomical characteristics of the medial branch of the lumbar dorsal rami and to discuss its possible clinical significance. SUMMARY OF BACKGROUND DATA: Radiofrequency ablation targeting the medial branch of the lumbar dorsal rami has been increasingly used in the clinical management of facetogenic low back pain (FLBP). Nonetheless, attention is also being given to complications such as atrophy of the lumbar soft tissues and muscles. Therefore, a more detailed understanding of the innervation pattern on the facet joint may improve the precision of nerve ablation therapy for FLBP. METHODS: An anatomical study of eight human specimens was carried out. The anatomic characteristics of the medial branch were observed and recorded. RESULTS: The medial branch originates from the lumbar dorsal rami, running close to the root of the posterolateral side of the superior articular process of the inferior cone. When passed through the mamillo-accessory ligament, it turns direction to the medial and caudal side, running in the multifidus muscle. In our study, each medial branch sent out two to five branches along the way. All the medial branches in L1-L4 gave off one to two small branches when crossing the facet joint and innervated the joint of the lower segment. Nineteen medial branches (23.75%) gave off recurrent branches to innervate the joint at the upper segment. CONCLUSION: The anatomical features of the medial branch remain similar in each lumbar segment. There are two types of joint branches, including the articular fibers that emanate from the medial branch as it runs along the medial border of the facet joint and the recurrent branch from the medial branch that innervates the upper facet joint. Moreover, an anastomotic branch was found in the medial branches between different segments.

Anatomic zone division and clinical significance of the lumbar sinuvertebral nerves.

BACKGROUND CONTEXT: Discogenic low-back pain (DLBP) is one of the primary causes of low back pain (LBP) and is associated with internal disc disruptions and is mainly transmitted by the sinuvertebral nerve (SVN). The lack of a universal understanding of the anatomical characteristics of the SVN has compromised surgical treatment for DLPB. PURPOSE: This study aims to elaborate on the anatomical characteristics of the SVN and to discuss their possible clinical significance. STUDY DESIGN: The SVNs were dissected and immunostained in ten human lumbar specimens. METHODS: The SVNs at the segments from L1-L2 to L5-S1 in ten human cadavers were studied, and the number, origin, course, diameter, anastomotic branches, and branching points of the SVNs were documented. Three longitudinal and five transverse zones were defined in the dorsal coronal plane of the vertebral body and disc. The vertebrae were divided longitudinally as follows: the region between the medial edges of the bilateral pedicles is divided into three equal parts, the middle third is zone I and the lateral third on both sides are zones II; the areas lateral to the medial margin of the pedicle were zones III. The transverse zones were designated as follows: (a)superior margin of the vertebral body to superior margin of the pedicle; (b) between superior and inferior margins of the pedicle; (c) inferior margin of the pedicle to inferior margin of the vertebral body; (d) superior margin of the disc to the midline of the disc; and (e) midline of the disc to the inferior margin of the disc. The distribution characteristics of SVNs in various zones were recorded, and tissue sections were immunostained with anti-NF 200 and anti-PGP 9.5. RESULTS: The SVNs are divided into main trunks and deputy branches, with 109 main trunks and 451 deputy branches identified in the 100 lumbar intervertebral foramens (IVFs). The main trunks of the SVN originate from the spinal nerve and/or the communicating branch, but the deputy branch originating from both roots was not observed. All the main trunks and deputy branches of the SVNs originate from the posterolateral disc (III d and III e). The deputy branches of the SVN primarily innervate the posterolateral aspect of the intervertebral disc (III d 46.78%, III e 36.36%) and the subpedicular vertebral body (III c 16.85%). The main trunk of the SVNs passes primarily through the subpedicular vertebral body (III c 96.33%) and divides into ascending, transverse, and descending branches in the IVF: III c (23/101, 22.77%) or spinal canal: II c (73/101, 72.28%), II d (3/101, 2.97%), II b (2/101, 1.98%). The main trunk possesses extensive innervation, and except for the most medial discs (I d and I e), it almost dominates all other zones of the spinal canal. At the segments from L1-L2 to L5-S1, 39 ipsilateral anastomoses connecting the ascending branch to the main trunk or spinal nerve at the upper level were observed, with one contralateral anastomosis observed at L5. CONCLUSION: The zone distribution characteristics of SVNs are similar across all levels. Comparatively, the proportion of double-root origin and the number of insertion points of the SVNs increased at the lower level. The three types of anastomosis offer connections between SVNs at the same level and at different levels. The posteromedial disc is innervated by corresponding and subjacent main trunks, with the posterolateral disc mainly innervated by the deputy branch. CLINICAL SIGNIFICANCE: Detailed information and zone distribution characteristics of the lumbar SVNs can help improve clinicians' understanding of DLBP and improve the effectiveness of treatments targeting the SVNs.

Sinuvertebral nerve block treats discogenic low back pain: a retrospective cohort study.

Background: Discogenic low back pain (DLBP) is considered the most common type of chronic low back pain (CLBP). Sinuvertebral nerve block (SVNB) is a rapid and precise intervention performed under local anesthesia to treat DLBP induced CLBP. Thus, in this study, we aimed to explore the clinical efficacy of SVNB for DLBP. Methods: We retrospectively included 32 DLBP patients from July 2020 and April 2021. Inclusion criteria: The patients had chronic pain, diagnosed as single-segment disc degeneration induced DLBP, and suffered from one-year ineffective conservative treatment. SVNB was performed and the patients were followed up at 3 and 7 days, and at 1 and 3 months after SVNB. The basic clinical characteristics, including age and gender, were collected. The measurements of Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) were assessed. Results: The average age was 49.31±14.37 years, and females vs. males was 20 (62.50%) vs. 12 (37.50%). The preoperative VAS and ODI score were 5.75±1.41 and 32.59±21.56, respectively. The VAS score was reduced to 2.50±1.46, 2.63±1.60, 3.53±2.17, and 3.78±2.18 at 3 and 7 days, and 1 and 3 months after SVNB, respectively (P<0.05). The improvement rates in the VAS score were 56.52%, 54.34%, 38.61%, and 34.26% at 3 and 7 days, and 1 and 3 months after SVNB, respectively. 18 patients (56.25%) experienced varying degrees of pain recurrence within 3 months. The ODI score was reduced by 17.28±13.06, 16.84±13.51, 19.63±17.12, and 21.44±19.03 points at 3, 7 days and 1, 3 months after SVNB, respectively (P<0.05). At 3 day and 3 month after SVNB, the ODI scores of 22 patients (68.75%) and 20 patients (62.50%) decreased to ≤20, respectively. The ODI improvement rates were 46.98%, 48.33%, 39.80%, and 34.24% at 3, 7 days and 1, 3 months after SVNB, respectively. Conclusions: We conducted a retrospective study of the clinical efficacy of SVNB for DLBP. As a rapid and cost-effective minimally invasive treatment, SVNB provided some assistance for the short-term pain relief and physical functional improvement of DLBP. SVNB could be a good choice for the treatment of DLBP.

Anatomical study and clinical significance of the posterior ramus of the spinal nerve of the lumbar spine.

Background and objectives: Chronic nonspecific back pain is a common clinical disease typically treated by ultrasound-guided spinal injection. This minimally invasive treatment targets the posterior ramus of the spinal nerve (PRSN). The target of the medial branch is clear, but there is unclear target for the intermediate and lateral branches. This study attempted to observe the distribution of PRSN in the dorsal region of transverse process to provide a more detailed anatomical basis for treating spinal pain. Methods: The present study was conducted on 16 transverse processes of six adult male embalmed corpses. The dorsal area of the transverse process was divided into three equal zones, which are zone I, zone II and zone III from inside to outside. The origin, distribution, quantity, transverse diameter, and relationship with the bone structure of the PRSN on the transverse process were observed. Results: Sixty PRSNs were found in the lumbar of six cadavers, of which 48 were divided into three branches, and 12 PRSNs were divided into two branches. The intermediate branch is mainly distributed in zone I, and the lateral branch is mainly distributed in zone II. Twenty-nine communicating branches were found in 48 adjacent segments of six specimens, all of which originated from the intermediate branch of the previous segment and connected with the lateral branch of the next segment. Conclusion: This anatomical study describing the PRSN may have important clinical significance for spinal surgeons. Understanding the bony localization targets of the PRSN and the links between the PRSNs may benefit patients with low back pain who receive spinal injections.

Anatomical study and clinical significance of rami communicantes of the lumbar spine.

BACKGROUND AND OBJECTIVES: Rami communicantes (RC) infiltration and radiofrequency lesions are new techniques for the treatment of discogenic low back pain (DLBP). Their efficacy is controversial, and the classification of RC remains unclear. We aimed to explore the differences between RC and reclassify RC according to their anatomical characteristics. METHODS: Sixteen sides of the lumbar spine from eight adult male embalmed cadavers were dissected. The presence of RC was noted. The morphology, origin, distribution, course, quantity and spatial orientation of RC on the lumbar spine were examined. The length and width of the RC were measured by a caliper. RESULTS: A total of 213 RC were found in the 8 cadavers in the lumbar region. RC were divided into three types: superficial rami (70, 32.86%), which penetrated the psoas major (PM) and ran above the aponeurosis of the PM; deep rami (125, 58.69%), which ran along the waist of the vertebral body beneath the aponeurosis of the PM; and discal rami, which ran over and adhered to the surface of the intervertebral disc. Superficial rami were divided into two subtypes: oblique rami (45, 21.13%) and parabolic rami (25, 11.74%), which crossed the vertebra and the disc in an oblique and a parabolic course, respectively. CONCLUSIONS: RC should play an important role in the innervation of the lumbar spine. Detailed knowledge of RC in the lumbar region may help surgeons improve the efficacy of infiltration and percutaneous radiofrequency as a supplementary treatment for DLBP.

An anatomical study of the origins courses and distributions of the transverse branches of lumbar arteries at the L1-L4 levels.

Pseudoaneurysms of the lumbar arteries following transforaminal lumbar interbody fusion (TLIF) are rare postoperative complications that usually occur around the transverse process. However, there are few detailed descriptions of the transverse branch and other branches of the dorsal branches at the L1-L4 disks. STUDY DESIGN: Ten adult embalmed cadavers were anatomically studied. OBJECTIVES: The purposes of the study were to describe the vascular distribution of the dorsal branches, especially the transverse branches, at the L1-L4 levels and provide information useful for TLIF. METHODS: Ten embalmed cadavers studied after their arterial systems were injected with red latex. The quantity, origin, pathway, distribution range and diameter of the branches were recorded and photographed. RESULTS: The transverse branch appeared in all 80 intervertebral foramina. The transverse branch was divided into 2 types: In type 1, the arteries divided into superior branches and inferior branches; the arteries in type 2 divided into 3 branches (superior, intermedius and inferior branches). CONCLUSIONS: The transverse branches of the dorsal arteries are common structures from L1 to L4, and 2 types of transverse branches were found. A thorough understanding of the dorsal branches, especially the transverse branches of the lumbar artery, may be very important for reducing both intraoperative bleeding during the surgery and the occurrence of pseudoaneurysms after transforaminal lumbar interbody fusion.

Anatomical study of the innervation of different parts of the posterior ligamentous region of the sacroiliac joint.

BACKGROUND AND OBJECTIVES: The periarticular sacroiliac joint (SIJ) technique has become an important area of focus, and the quartering of the SIJ posterior ligamentous region has been proposed as a way to refine this technique. However, detailed nerve distribution combined with the division of the SIJ posterior ligamentous region is lacking. We aimed to explore the innervation of the SIJ posteriorly based on the quartering of the SIJ posterior ligamentous region. METHODS: Sixteen SIJs from eight embalmed cadavers were studied. Each SIJ posterior ligamentous region was equally divided into areas 0-3 from top to bottom. The origin, distribution, quantity, transverse diameter, spatial orientation, relation with bony structures, and the number of identifiable terminal nerve branches in each area were examined. RESULTS: Areas 0-1 were innervated by the lateral branches of the dorsal rami of L4-L5 directly in all specimens. Areas 2-3 were innervated by that of both lumbar and sacral nerves via the posterior sacral network (PSN), with L5 contributing to the PSN in all specimens and L4 in 68.75%. The number of identifiable terminal nerve branches were significantly higher in areas 2-3 than in areas 0-1. CONCLUSIONS: The inferior part of the SIJ posterior ligamentous region seems to be the main source of SIJ-related pain and is innervated by lumbar and sacral nerves via the PSN. However, the superior part directly innervated by lumbar nerves should not be neglected, and further clinical verification is needed.