Proximal Versus Distal Superior Cluneal Nerve Block in Entrapment Neuropathy

Official title

Proximal Versus Distal Superior Cluneal Nerve Block in Superior Cluneal Nerve Entrapment: A Prospective, Randomized, Single-Blind Trial

Overview

Superior cluneal nerve (SCN) entrapment is an underdiagnosed cause of chronic low back and gluteal pain. Although diagnostic nerve block is considered the gold standard for confirming SCN entrapment, there is no consensus regarding the optimal injection approach. This prospective observational study aims to compare the clinical effectiveness of proximal and distal ultrasound-guided SCN block techniques in patients diagnosed with SCN entrapment. Pain intensity and functional outcomes will be evaluated over the follow-up period to assess differences between the two approaches.

Detailed description

The primary objective of this study is to compare the effects of two different ultrasound-guided injection techniques on pain intensity, functional status, neuropathic pain components, and quality of life in patients with suspected superior cluneal nerve (SCN) entrapment. Pain severity will be assessed using the Visual Analog Scale (VAS), functional status using the Oswestry Disability Index (ODI), neuropathic pain components using the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS), and quality of life using the Short Form-12 (SF-12). The study aims to determine which injection technique provides superior clinical outcomes.

The secondary objective is to evaluate lumbosacral angle, lumbar lordosis angle, pelvic tilt, sacral tilt, and the presence of scoliosis, and to investigate the relationship between these postural and radiological parameters, SCN entrapment, and treatment response.

Through this study, ultrasound-guided injection techniques used in the diagnosis and treatment of SCN entrapment will be comparatively evaluated, addressing an important gap in the current literature and providing high-level scientific evidence to guide clinicians in the management of chronic low back and gluteal pain.

This study is designed as a prospective, randomized, single-blind clinical study comparing two different ultrasound-guided injection techniques in patients with suspected superior cluneal nerve entrapment. The study population will consist of patients presenting to the Algology Outpatient Clinic of Health Sciences University Gaziosmanpaşa Physical Medicine and Rehabilitation Training and Research Hospital during the study period, who meet the inclusion and exclusion criteria, have chronic low back and/or gluteal pain, are suspected of having SCN entrapment based on clinical examination, have not benefited from conservative treatment, and voluntarily agree to participate in the study.

Based on a power analysis with 95% power, a total of 54 patients are planned to be included in the study, with 27 patients allocated to each group.

Interventions

• Procedure Ultrasound-guided distal superior cluneal nerve injection
  The ultrasound probe will be placed over the posterior superior iliac crest to visualize the fibro-osseous tunnel where the superior cluneal nerve passes. Using an in-plane approach, the needle will be advanced toward the target area, and the injection will be administered at the fascial exit point of the nerve. A total injectate volume of 5 cc (2 cc bupivacaine, 2 cc dexamethasone, and 1 cc normal saline) will be administered. All procedures will be performed in the prone position under standar
• Procedure Ultrasound-guided proximal superior cluneal nerve injection
  Patients randomized to the proximal injection group will undergo ultrasound-guided injection above the iliac crest level. The target will be the plane beneath the posterior layer of the thoracolumbar fascia. Using an in-plane approach, the injectate will be delivered into the interfascial plane. A total injectate volume of 5 cc (2 cc bupivacaine, 2 cc dexamethasone, and 1 cc normal saline) will be administered under ultrasound guidance. Patient positioning and aseptic conditions will be identica

Primary outcome measures

• Visual Analog Scale (VAS) [Time frame: Baseline, 1 month, and 3 months]

Secondary outcome measures (4)

• Oswestry Disability Index (ODI) [Time frame: Baseline, 1 month, and 3 months]
• Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) [Time frame: Baseline, 1 month, and 3 months]
• Short Form-12 Health Survey (SF-12) [Time frame: Baseline, 1 month, and 3 months]
• Baseline Postural and Radiological Characteristics in Patients with Superior Cluneal Nerve Entrapment [Time frame: Baseline (pre-intervention)]

Eligibility criteria

Inclusion criteria

• Age between 18 and 75 years
• Chronic low back and/or gluteal pain lasting longer than 3 months
• Localized point tenderness and/or paresthesia on palpation over the unilateral posterior iliac crest
• Clinical suspicion of superior cluneal nerve entrapment based on physical examination
• Failure to respond to conservative treatment
• Ability and willingness to provide written informed consent

Exclusion criteria

• Active local or systemic infection
• Cognitive impairment or psychiatric disorders interfering with study participation
• History of malignancy or cancer-related pain
• Uncontrolled diabetes mellitus or severe comorbid conditions adversely affecting general health
• Pregnancy
• Known allergy to the medications used in the injection
• Prominent radicular pain associated with neurological deficit
• History of interventional procedures applied to the lumbar region within the last 6 months
• Initiation of another lumbar interventional or medical treatment during the follow-up period
• Suspected bilateral superior cluneal nerve entrapment
• Sphincter dysfunction related to neurological disease
• Bleeding diathesis or coagulation disorders

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

Turkey (Türkiye) · 1 center

• Health Sciences University Gaziosmanpaşa Physical Medicine and Rehabilitation Training and — Istanbul

Publications

• Nielsen TD, Moriggl B, Barckman J, Jensen JM, Kolsen-Petersen JA, Soballe K, Borglum J, Bendtsen TF. Randomized trial of ultrasound-guided superior cluneal nerve block. Reg Anesth Pain Med. 2019 May 6:rapm-2018-100174. doi: 10.1136/rapm-2018-100174. Online ahead of print. PMID 31061111
• Bodner G, Platzgummer H, Meng S, Brugger PC, Gruber GM, Lieba-Samal D. Successful Identification and Assessment of the Superior Cluneal Nerves with High-Resolution Sonography. Pain Physician. 2016 Mar;19(3):197-202. PMID 27008294

Identifiers

NCT: NCT07372430 · 1496

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗