Lympho-SPECT/CT as a tool to evaluate postoperative outcomes after LVA for lymphedema repair

Aim: To describe findings when comparing lympho-SPECT-CT images before and after lymphovenous anastomosis (LVA) surgeries and to correlate these results with pre- and post-operative volume changes in the limbs of patients.Methods: An observational, prospective, longitudinal study was designed. 20 consecutive patients were treated for lymphedema by means of LVA between 2015 and 2018. All were affected by secondary lymphedema (ISG II-III) following lymphadenectomy, radiation or both. All patients received preoperative rehabilitation as well as radiotherapy after oncological surgery. Limb volume was measured before surgery and at one year later. LVA was performed under general anesthesia with ICG guidance. ICG was also used to evaluate postoperative outcomes. Lympho-SPECT-CT was performed in all subjects at their first consultation and at one year after every surgical intervention. Description of findings included an absence of lymph nodes, new lymph node activity in anatomical areas and new lymphatic activity in extra-anatomical areas.Results: Limb volume decreased in 19 patients after LVA. Six patients showed preoperative linear ICG patterns, combined with areas presenting with another type of pattern. After LVA, the linear pattern was observed in 11 patients. SPECT-CT/lymphoscintigraphy before surgery showed a total absence of lymph nodes, except in two cases, in whom small nodes in anatomical locations were described. After LVA, we observed new landmarks in 16 patients corresponding to lymphatic circulation that was not present in preoperative studies. In six cases, new lymphatic activity compatible with lymph nodes was detectable after LVA. The Spearman correlation coefficient was negative when circumferences and lympho-SPECT-CT were tested (P = 0.02).Conclusion: Results showed a postoperative decrease in volume that correlated inversely with lympho-SPECT/CT findings. Lympho-SPECT/CT provided additional information related to accurate identification and the anatomical location of lymphatic structures that were not observed before reconstructive surgery. It can be a complementary test to conventional lymphoscintigraphy