Pectoralis Minor Tenotomy with Occasional Secondary Neurolysis Significantly Reduces Self-Reported Pain and Headaches...

Background and Objectives: Many patients suffer from chronic pain of the shoulder, neck, upper back, and/or arm. They may be diagnosed with fibromyalgia, complex regional pain syndrome, myofascial pain, thoracic outlet, subacromial pain, cervical radiculopathy, cervicogenic headaches, post-mastectomy pain, and/or occupational shoulder disorder. The pectoralis minor (PM) is the only muscle of the scapula controlled by the lower trunk of the brachial plexus. In the Human Disharmony Loop (HDL), this neurologic asymmetry produces persistent protraction of the scapula. Protraction deforms the scapula's connections, generating headaches and neck stiffness, upper back tightness, shoulder weakness, and hand numbness. We hypothesize patients with the above who meet HDL diagnostic criteria will benefit from PM tenotomy with brachial plexus neurolysis (PM+ICN). Materials and Methods: Patients diagnosed with the above disorders who also met HDL criteria of medial coracoid tenderness and scapula protraction on exam underwent PM+ICN, with secondary neurolysis after 3 months if needed. Clinical neuropathy was diagnosed via the scratch-collapse test. Outcomes included self-reported Visual Analogue Score pain scores, active shoulder abduction range of motion (ROM), prevalence of occipital headaches. Results: N = 318 patients were included. Average age was 51; 68.0% were female. Following treatment, average pain decreased from 7.3/10 to 2.1/10 (p < 0.001), average shoulder ROM increased from 96 to 170 degrees (p < 0.001), and occipital headaches decreased from 76.7% to 1.6% (p < 0.001). Scapular protraction normalized from 98.8% static to 92.5% none (p < 0.001). Overall, 17% required subsequent neurolysis, chiefly of the axillary, radial, and ulnar nerves. The pain reductions were statistically indistinguishable across all diagnoses (p = 0.709, I² = 0.02%). Average follow-up was 22 months. Conclusions: PM+ICN significantly reduced self-reported pain and headaches in select intractable patients. The PM pathologizing the scapula may constitute a shared anatomic mechanism that contributes to chronic pain across heterogenous disorders of the upper limb.