Long Term Outcome of Splenectomy in Pediatric Patients with Non-Malignant Hematological Diseases: Four Decades of Follow up

Elective splenectomy in childhood can ameliorate the clinical manifestations of non-malignant hematological diseases such as beta-thalassemia, hereditary spherocytosis and chronic immune thrombocytopenia. The advantages however, must be weighed against possible adverse effects. The incidence of infectious complications post splenectomy has decreased as a result of the introduction of novel vaccinations and antibiotic prophylaxis, however this depends on patient compliance. The risk of thromboembolism appears to be related to the underlying diagnosis, although the exact long-term risk has not been well documented. There is a paucity of reports describing large cohorts and long term follow-up of splenectomized hematological patients. We present herein four decades, comprising 1652 patient years, of follow-up of patients who underwent splenectomy in childhood for non-malignant hematological diseases, evaluating the risk of infection and thromboembolic complications.

Medical records were screened for the diagnosis of splenectomy among patients previously or currently treated in our pediatric hematology clinic. Demographic, clinical and laboratory data, including the diagnosis, age at time of surgery, infectious and thrombotic complications were recorded. Bacterial infection was defined as positive blood cultures taken due to febrile illness. Thrombotic events included venous thrombosis diagnosed by appropriate imaging. For patients lost to follow up, a telephone follow-up visit was performed using a brief questionnaire focusing on the complications of interest.

One hundred and four (104) patients underwent splenectomy between 1974-2015 for the diagnoses of beta-thalassemia major (TM)(33), beta-thalassemia intermedia (TI)(7), sickle-thalassemia (ST)(4), hereditary spherocytosis (HS)(42) or immune thrombocytopenia (ITP)(18). The follow-up period encompasses a total of 1652 years (mean=16, range=1-40 per patient). Mean age at splenectomy was 11.4 years (0.5-25). Vaccinations according to the recommended protocol at time of surgery were administered to 98% of patients. Forty-four bacterial infections occurred in 21 patients. Twenty four percent of the first infections occurred in the first year post-splenectomy, while 67% were within five years post-splenectomy. Only 1 of 7 reported deaths was due to sepsis, in a ST patient. Eight thrombotic events occurred in the cohort, 7 among TM patients with central venous lines (CVL) and 1 case of a postoperative portal vein thrombosis (PVT) in a patient with HS. In univariate analysis, CVL and thalassemia diagnoses were each predictive for both infectious and thrombotic complications (p<0.001). However, in multivariate logistic regression, only the presence of CVL maintained significance (p<0.001).

Our study of 104 patients with 1652 years of cumulative follow-up shows an extremely low risk for infectious and thrombotic complications: 1.3 and 0.5 per 100 years at risk, respectively. Only one patient each among the ITP and HS groups developed bacterial infection and the only thrombotic event in a non-thalassemic patient was an immediately post splenectomy PVT in a patient with HS. The majority (19/21) of infections occurred in thalassemic patients, 63% of which had a CVL. Thrombosis beyond the post-operative period occurred exclusively among thalassemic patients with CVL. Infection occurred primarily within 5 years after splenectomy and was fatal in only 1 case.

Splenectomy in pediatric patients with non-malignant hematological diseases is a safe procedure with minimal infectious and thrombotic complications particularly among patients with HS or ITP. Abiding by the pre-splenectomy vaccination guidelines for all patients and prudent use of CVLs in splenectomized thalassemic patients should contribute to minimizing long term complications.