Leech therapy in chronic shoulder pain: a randomized pilot study
Müller IM, Stange R, Heider U, Uehleke B, Cesur Ö, Michalsen A (2010) · Forschende Komplementärmedizin · n=24
RCT evidence detailTrial reference
GRADE LowCohort / case series
Study Profile
- Design
- single-center, open-label, randomized pilot trial (Essen)
- Sample size (n)
- 24
- Intervention
- Single session of 4-7 Hirudo medicinalis leeches around the painful shoulder (anterior, lateral, posterior)
- Comparator
- Topical diclofenac gel applied 4 times daily for 28 days
- Primary endpoint
- Pain on 100mm VAS at day 7
- Primary result
- VAS pain reduction 35.6mm in leech vs 14.1mm in diclofenac at day 7 (between-group difference 21.5mm, 95% CI 9.3-33.7, p=0.001)
- Effect size (Cohen's d)
- 0.94
- Follow-up duration
- 8 weeks
Key Findings
- Effect size for shoulder pain comparable to knee OA RCTs (Cohen's d ≈ 0.94)
- DASH score improved 12 points in leech vs 4 points in diclofenac
- Mixed shoulder pain etiologies included (rotator cuff, frozen shoulder, subacromial impingement)
- Effect sustained through 8 weeks
- Adverse events mild and self-limited
Limitations
- Small pilot (n=24)
- Mixed diagnoses limit attribution to specific pathology
- Open-label
- Single center
- No imaging endpoints (no rotator cuff status, no impingement angle)
Clinical Implications
Müller 2010 is the only RCT-level evidence for hirudotherapy in chronic shoulder pain. The mixed-etiology design weakens specificity but reflects clinical reality (shoulder pain is often etiologically ambiguous). Clinicians can cite this trial as supporting cautious use in patients with shoulder pain refractory to NSAIDs and exercise, while recognizing the very limited evidence base.