The saline bag spacer technique for stereotactic biopsy of thin breasts

Stereotactic-guided core biopsy (SGCB) is the standard technique to sample mammographically detected calcifications and other findings not amenable to ultrasound guidance. A limitation of SGCB is the requirement of sufficient breast thickness to allow safe needle penetration and sampling, typically ≥ 3 cm for standard needles and ≥ 2 cm for petite needles. SGCB may be cancelled in patients with very thin breasts or when the target lies against the detector side skin. While various maneuvers to increase tissue thickness have been described when breasts are too thin even for petite needles, such as the lateral arm technique, a subset of SGCBs are still cancelled, leading to delays in diagnosis and treatment. To address this gap that still exists for minimally invasive sampling of thin breasts, we describe a novel saline bag spacer technique. This consists of placing a 250 ml sterile saline bag between the breast and detector during compression to increase compression thickness and provide a safe backstop for the biopsy needle. In our initial institutional experience (12 patients referred after outside cancellation), all procedures were completed with target sampling without clinically significant complications. The saline bag technique is a low cost, readily available adjunct that can expand access to minimally invasive diagnosis and help avoid surgical excisional biopsy.