Does ArcPy have spatial search function for geometry?

My problem: Using ArcPy I want to loop over buffers and select geometry_features inside each buffer and do something (update) only the objects found within that specific buffer. The code below explains what I want to do (more or less):

def _update_connections_inside_buffers(self):
    buffers = arcpy.SearchCursor(self.__buffer_class_name)
    in_layer = "connections"
    for i_buffer in buffers:
        shape = i_buffer.shape
        # can not use a geometry to do a selection.. very inconvenient!!
        connections = arcpy.SelectLayerByLocation_management(in_layer, "WITHIN", shape) 
        self._update_connections(connections)

However: this will not work because SelectLayerByLocation_management() does not accept a geometry, "shape" as an argument but expects a feature_class_name (layer name). Is there a arcpy method that can do a search using a spatial predicate. I could not find how to do this from the ESRI manual.