Indocyanine green (ICG) imaging: case report of innovative isthmocele diagnosis and repair in a post-ablation patient and literature review.

An isthmocele, although often asymptomatic, may cause symptoms such as AUB and pelvic pain [ 2 ]. An isthmocele can be defined as a pouch-like defect, also called cesarean scar defect or uterine niche, in the anterior uterine wall at the site of a prior cesarean section [ 3 ]. It can lead to complications such as infertility, abnormal placentation, scar dehiscence, uterine rupture, and ectopic pregnancy [ 2 , 3 , 4 ]. Contributing factors to the formation of isthmoceles include low or incomplete hysterotomy closures, prolonged active labor, early uterine adhesions, peripartum infection, and maternal comorbidities [ 5 ]. Accurate diagnosis typically involves two-dimensional transvaginal ultrasound (2D-TVUS) with saline infusion sonohysterogram (SIS), recognized for its specificity and cost-effectiveness. Treatment favors minimally invasive techniques like hysteroscopy and/or laparoscopy, tailored by defect size and symptoms. For patients with a residual myometrial thickness of 2–3 mm, the hysteroscopic approach has been identified as the most effective method for addressing abnormal uterine bleeding, secondary infertility, and pain. However, when the RMT is less than 2–3 mm, the laparoscopic approach is preferred for optimal outcomes, reducing the risk of complications such as uterine perforation and bladder injury [ 6 , 7 ]. Utilization of intrauterine ICG prior to surgical repair enhanced visualization of the isthmocele in this case. It allowed for more precise identification of the defect and facilitated a more effective surgical repair, involving a combined hysteroscopic and laparoscopic approach. This technique reduced operative time and minimized intraoperative complications, demonstrating its superiority over traditional methods. It is important to note that this technique works optimally in cases with no or very low RMT, as was present in our patient's case. In cases with cystic isthmoceles, where fluid accumulation creates a fluid-filled sac within the defect, this method may be less effective as the fluid could dilute the ICG and reduce its fluorescence, limiting visualization. A cystic isthmocele is a specific type of isthmocele characterized by the presence of fluid accumulation within the defect [ 8 , 9 ]. The intrauterine application of ICG to enhance laparoscopic visualization of an isthmocele was previously described by Krentel et al. in 2022, showing promising results similar to our experience [ 1 ]. ICG can prove to be valuable particularly for identifying subtle anatomical defects that may be challenging to visualize despite using a combined hysteroscopic and robotic-assisted laparoscopic visual approach. A systematic review revealed that hysteroscopic surgery for RMT of at least 2.5 mm is effective in treating secondary subfertility associated with an isthmocele [ 10 ]. Isthmocele surgery has been shown to relieve  AUB, pain, and infertility regardless of the surgical route chosen [ 11 ]. However, some evidence suggests that for patients with a history of infertility, ectopic pregnancy, lower gravidity, lower parity, and fewer cesarean sections, a laparoscopic isthmoplasty might be preferred [ 12 ]. Despite these findings, the literature sometimes presents a confusing clinical picture regarding the surgical management of isthmoceles. This is partly due to a lack of robust evidence supporting the role of surgery in improving fertility or reducing obstetric complications [ 13 ]. Nonetheless, our understanding of the best practices for managing isthmoceles continues to evolve as more research is conducted and additional data become available. This ongoing evolution highlights the necessity for further studies to clarify the most effective approaches and to establish standardized guidelines for clinical practice [ 14 ]. In conclusion, while the management of isthmoceles remains complex and sometimes controversial, advancements in surgical techniques, such as the use of ICG for enhanced visualization, offer promising improvements in patient outcomes. Continued research and comprehensive reviews of current literature are essential for refining these techniques and improving the standard of care for patients with isthmoceles.