Dictionary.com provides the following explanation for the word 'parenthesis' including an expression, "without otherwise", to make it clear. But, the word 'without' is enough to convey the intended meaning. When I take the complete expression (i.e. without otherwise), it really confuses me. I hope this comes from legal language. Please read the text below and clarify the importance of the expression - without otherwise.
Parenthesis: a qualifying, explanatory, or appositive word, phrase, clause, or sentence that interrupts a syntactic construction without otherwise affecting it, having often a characteristic intonation and indicated in writing by commas, parentheses, or dashes, as in William Smith—you must know him—is coming tonight.