A New Lymphoscintigraphy Staging for Unilateral Extremity Lymphedema: Validation and Correlation between Nuclear Images and Clinical Findings

Background: Approximately 200 million people worldwide suffer from lymphedema.¹ Appropriate diagnosis and staging are fundamental for the management of patients with extremity lymphedema.^2,3 Lymphoscintigraphy has long been considered the imaging modality of choice for the diagnosis of lymphatic disorders.^4,5 The purpose of this study was to validate the new Lymphoscintigraphy Staging system for unilateral extremity lymphedema based on a precision medicine concept and to investigate the correlation between the lymphoscintigraphy findings and objective clinical findings.

Methods: A review of a prospective database was performed for patients with suspected lymphedema who had undergone lymphoscintigraphy for diagnosis and assessment of lymphedema. Patients with unilateral extremity lymphedema were included. Lymphoscintigraphy images were divided into three types: normal drainage, partial obstruction, and total obstruction based on the visualization of proximal lymph nodes, linear lymphatic ducts, and dermal backflow. Clinical severity of extremity lymphedema was determined using a 5­-grade Lymphedema Grading System based on the circumferential difference between the lymphedematous limb and the healthy limb. Relationship between lymphedema severity and lymphoscintigraphy staging was determined using Spearman Correlation coefficient.

 

Results: We present the largest series in the world of 285 patients with unilateral extremity lymphedema who underwent complex decongestive therapy and lymphedema microsurgery. Patients were divided as follows: 3.9% with normal drainage, 44.9% with partial obstruction, and 51.2% with total obstruction.

High inter-­observer (average ICC: 0.93) and intra-observer reliability (ICC=0.75-0.91) of the Lymphoscintigraphy Staging system was found. The Lymphoscintigraphy Staging system showed substantial correlation with objective clinical findings such as circumferential difference (upper extremity r=0.79, lower extremity r=0.75), CT volumetric difference (upper extremity r=0.62, lower extremity r=0.70), and Lymphedema Grading System (ICC upper extremity=0.81, lower extremity= 0.77). Patients with total obstruction of the lymphatics should be treated with vascularized lymph node transfer, whereas those with partial obstruction can be managed with lymphovenous bypass.

 

Conclusions: The new Lymphoscintigraphy Staging system is a reliable and comprehensive tool for the assessment of lymphatic obstruction. For refractory extremity lymphedema, the Lymphoscintigraphy Staging system should be applied to guide appropriate treatment options.

 

References

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