Optimizing needle length and site choice for adult immunization.

BACKGROUND: Current recommendations for needle length and vaccination site for intramuscular deltoid vaccinations are backed by minimal data. AIM: To determine the ideal needle length and vaccination site for intramuscular deltoid vaccine administration. METHODS: 120 shoulder CT scans were evaluated and grouped by patient weight and sex as recommended by the United States CDC: Group 1, <60 kg, Group 2, 60-70 kg, Group 3, females 70-90 kg and males 70-118 kg, and Group 4, females > 90 kg and males > 118 kg. For each group, distance from skin to deltoid fascia and deltoid muscle width were measured at 2, 4, and 6 cm distal to the posterolateral corner of the acromion for 5 unique trajectories. Needle lengths of 0.625″, 1.0″, and 1.5″ were simulated at each site to determine inoculation location relative to the deltoid. RESULTS: For Group 1, a 0.625″ needle in the mid-lateral (ML) trajectory 4 cm distal to the posterolateral corner provided a perfect rate of successful inoculations (100 %). For Groups 2-3, a 1″ needle in the posterolateral (PL) trajectory 4 cm distal provided high rates (>80 %) of successful intramuscular inoculations with low rates of overpenetration (<15 %) while minimizing risk to the axillary nerve. For Group 4, a 1.5″ needle using the same strategy provided the highest rate of successful inoculations (96 %) and minimal overpenetration (4 %). Overpenetration was associated with more anterior and superior injection sites (P < 0.001 for both) for all needle lengths. CONCLUSIONS: The overall ideal injection site to maximize successful intramuscular vaccine administration, minimize overpenetration, and avoid axillary nerve injury is 4 cm distal to and in line with the posterolateral corner of the acromion, a site more posterior and inferior than current CDC recommendations. We caution against use of a 1.5″ needle for patients < 118 kg due to high predicted rates of overpenetration.

Shoulder Pain and Dysfunction After Vaccination: A Systematic Review.

BACKGROUND: Persistent shoulder pain and dysfunction after vaccination are relatively rare but well-known complications after inoculations into the deltoid muscle. The term SIRVA (shoulder injury related to vaccine administration) is frequently used to encompass many of these occurrences; however, multiple distinct pathologies with similar presentations have been reported after vaccination. We performed a systematic review of the literature on vaccine-related shoulder injuries to help guide practitioners in appropriate workup and treatment based on specific diagnoses. METHODS: PubMed was used to search for combinations of multiple keywords (including vaccine, immunization, SIRVA, injury, inflammation, bursitis, Parsonage-Turner syndrome, and neuritis), and all references of each potential article were reviewed. A total of 56 articles were included. Patient demographics, vaccine information, presentation, diagnostic studies, treatment, and outcomes were recorded. RESULTS: Diagnoses were divided into 3 categories: (1) local inflammatory reaction (SIRVA), (2) brachial neuritis, and (3) direct nerve injury. The included articles reported on 57 cases of SIRVA, 18 of brachial neuritis, and 4 of direct nerve injury. The diagnoses reported for the SIRVA cases included frozen shoulder, pseudoseptic arthritis, subacromial bursitis, rotator cuff injury, and lytic lesions of the humeral head. Various treatments were used, and most patients had resolution of symptoms with conservative treatment including physical therapy, analgesics, and/or corticosteroid injections. Advanced imaging rarely provided information that affected treatment. The brachial neuritis and direct nerve injury cases were typically confirmed with electromyography/nerve conduction studies. Treatment of these 2 categories was nonoperative in all cases, typically with analgesics and/or corticosteroids, and most patients had symptomatic improvement after a few months, with most patients regaining strength. However, some (1 of 3 patients with brachial neuritis and >1 year of follow-up and 2 of 4 patients with direct injury) had residual weakness. CONCLUSIONS: Medical professionals should be aware of the various pathologies that can lead to prolonged shoulder pain after vaccination. Fortunately, most of these conditions can be treated successfully with nonoperative modalities, although differentiating among the diagnoses can help guide treatment, as some likely benefit from systemic corticosteroids or localized corticosteroid injections. Outcomes for most patients have been good, with the majority recovering without residual pain or deficits. LEVEL OF EVIDENCE: Prognostic Level IV.