Perineural Injection Treatment for Shoulder Pain

Shoulder pain is one of the most prevalent musculoskeletal disorders and is associated with substantial disability and reduced quality of life. The etiology is multifactorial, involving structures such as the rotator cuff, glenohumeral joint, and surrounding soft tissues. In addition to nociceptive mechanisms, neuropathic and nociplastic components may contribute to persistent pain, making management challenging.

Conventional treatments, including pharmacological therapy, physical therapy, and injection-based interventions, have shown variable effectiveness and may provide only short-term relief. Therefore, there is increasing interest in minimally invasive interventions that target peripheral sensitization.

Perineural Injection Treatment (PIT) is a therapeutic approach involving subcutaneous injection of low-concentration dextrose solution along peripheral nerve pathways. It is proposed to reduce neurogenic inflammation and modulate nociceptor activity, potentially leading to improved pain and function. However, evidence regarding its effectiveness in shoulder pain remains limited.

This study is designed as a single-blind randomized controlled trial comparing PIT with Transcutaneous Electrical Nerve Stimulation (TENS) in patients with subacute or chronic shoulder pain. A total of 32 participants are randomly assigned to either the PIT group or the TENS group. Both groups receive a standardized exercise program, including active range of motion, stretching, and strengthening exercises.

The intervention consists of two treatment sessions administered over a two-week period. PIT is performed using subcutaneous injections of 5% dextrose along painful peripheral nerve areas. TENS is applied using conventional parameters with frequency 75-100 Hz and pulse width less than 200 microseconds.

Outcome measures include pain intensity assessed using the Numeric Rating Scale (NRS) and functional status evaluated using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. Assessments are conducted at baseline, immediately after intervention, and at the end of the intervention period.

The primary objective of this study is to evaluate the effectiveness of PIT in reducing pain intensity compared to TENS. Secondary objectives include assessing functional improvement and immediate analgesic effects following intervention.

The findings of this study are expected to contribute to evidence-based management of shoulder pain and support the use of mechanism-based interventions targeting peripheral nociceptive pathways.

• Dextrose 5% Injection (Drug): A 5% dextrose solution is administered via subcutaneous perineural injection targeting painful peripheral nerve areas using a fine needle.
• Transcutaneous Electrical Nerve Stimulation (TENS) (Device): TENS is applied using conventional mode with a frequency of 75-100 Hz and pulse width less than 200 microseconds, delivered for approximately 20 minutes per session.
• Exercise Program (Behavioral): A standardized exercise program including active range of motion, stretching, and strengthening exercises using elastic resistance bands.

Primary outcomes

• Change in Pain Intensity Measured by Numeric Rating Scale (NRS) [Baseline to 2 weeks]: Pain intensity is assessed using the Numeric Rating Scale (NRS), ranging from 0 (no pain) to 10 (worst imaginable pain). The outcome is defined as the change in NRS score from baseline to the end of the intervention period.

Secondary outcomes

• Change in Functional Status Measured by Disabilities of the Arm, Shoulder and Hand (DASH) [Baseline to 2 weeks]: Functional status is assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, with scores ranging from 0 to 100, where lower scores indicate better function. The outcome is defined as the change in DASH score from baseline to the end of the 2-week intervention period.

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* Adults aged 18-65 years
* Patients with subacute or chronic shoulder pain
* Pain intensity ≥ 3 on the Numeric Rating Scale (NRS)
* Diagnosed with shoulder conditions such as adhesive capsulitis, rotator cuff tendinopathy or tear, glenohumeral osteoarthritis, acromioclavicular joint sprain, or biceps tendinopathy
* Able to provide informed consent

Exclusion Criteria:

* History of injection therapy or use of analgesic medications within one week prior to intervention
* Presence of neurological or systemic diseases affecting upper limb function
* Pregnancy
* Contraindications to injection therapy (e.g., infection at injection site, needle phobia, allergy to dextrose)
* Refusal to participate or inability to complete the study protocol