diff --git a/dictionaryweights/src/main/java/edu/harvard/dbmi/avillach/dictionaryweights/WeightUpdateCreator.java b/dictionaryweights/src/main/java/edu/harvard/dbmi/avillach/dictionaryweights/WeightUpdateCreator.java
index 1de1d56..f3ccafc 100644
--- a/dictionaryweights/src/main/java/edu/harvard/dbmi/avillach/dictionaryweights/WeightUpdateCreator.java
+++ b/dictionaryweights/src/main/java/edu/harvard/dbmi/avillach/dictionaryweights/WeightUpdateCreator.java
@@ -22,7 +22,7 @@ public String createUpdate(List<Weight> weights) {
             .collect(Collectors.joining(", ' ',\n            "));
         return """
             UPDATE concept_node
-            SET SEARCHABLE_FIELDS = to_tsvector(data_table.search_str)
+            SET SEARCHABLE_FIELDS = to_tsvector(replace(data_table.search_str, '_', '/'))
             FROM
             (
                 SELECT
diff --git a/src/main/java/edu/harvard/dbmi/avillach/dictionary/facet/FilterPreProcessor.java b/src/main/java/edu/harvard/dbmi/avillach/dictionary/facet/FilterPreProcessor.java
new file mode 100644
index 0000000..f2fc7dc
--- /dev/null
+++ b/src/main/java/edu/harvard/dbmi/avillach/dictionary/facet/FilterPreProcessor.java
@@ -0,0 +1,49 @@
+package edu.harvard.dbmi.avillach.dictionary.facet;
+
+import edu.harvard.dbmi.avillach.dictionary.filter.Filter;
+import org.springframework.core.MethodParameter;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.util.StringUtils;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+
+@ControllerAdvice
+public class FilterPreProcessor implements RequestBodyAdvice {
+    @Override
+    public boolean supports(
+        MethodParameter methodParameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType
+    ) {
+        return true;
+    }
+
+    @Override
+    public HttpInputMessage beforeBodyRead(
+        HttpInputMessage inputMessage, MethodParameter parameter, Type targetType,
+        Class<? extends HttpMessageConverter<?>> converterType
+    ) throws IOException {
+        return inputMessage;
+    }
+
+    @Override
+    public Object afterBodyRead(
+        Object body, HttpInputMessage inputMessage, MethodParameter parameter,
+        Type targetType, Class<? extends HttpMessageConverter<?>> converterType
+    ) {
+        if (body instanceof Filter filter && StringUtils.hasLength(filter.search())) {
+            return new Filter(filter.facets(), filter.search().replaceAll("_", "/"));
+        }
+        return body;
+    }
+
+    @Override
+    public Object handleEmptyBody(
+        Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType,
+        Class<? extends HttpMessageConverter<?>> converterType
+    ) {
+        return body;
+    }
+}