The theoretical part Grammar references

The Difference between Verbal Nouns and Gerunds
Verbal nouns are not the same as gerunds (another type of noun formed from a verb).
A gerund is a noun that, having derived from a verb, retains a few verb-like properties. For example, a gerund can be modified by an adverb and can take a direct object.
Compare these two examples. The first contains a verbal noun; the second, a gerund.
 This bad drawing of a dog is not acceptable for your project.

(This is a verbal noun. It is acting just like a noun. Just as any noun could have, it has a determiner (This) and an adjective (bad), and it is followed by a prepositional phrase (of a dog).)

 Badly drawing a dog is not acceptable for your project.

(This is a gerund. It is functioning as a noun, but it has two notable verb-like properties. Just as any verb could have, it has an adverb (badly) and a direct object (a dog).)

Verbal nouns (or pure verbal nouns as they're sometimes called) are common in business writing because they carry an air of formality. As a result, it is not uncommon to read a sentence like this in business email:
 The implementation of the new system will commence on Monday.

(This formal sentence features the pure verbal noun implementation.)

So, if you're looking for a formal tone, you could consider verbal nouns for your sentences. However, verbal nouns can also portray you as straight-laced and starchy.
The analytical part
New words
The retention of urine is one of the clinical manifestations of a kidney disease.
stool
The laboratory analysis of the stool failed to reveal any blood.
tenderness
The patient complained of a moderate tenderness on palpation.
remove
The surgeon removed the tumor which had involved the stomach