Vor der Untersuchung hatte ich Angst vor der Spritze, aber der Verband war am Ende das Einzige, was nötig war.

It is the same preposition, but it has two different uses here:

• Vor der Untersuchung = before the examination
  Here vor expresses time.

• Angst vor der Spritze = fear of the injection
  Here vor is part of the fixed expression Angst vor etwas haben = to be afraid of something.

So the word is the same, but the meaning depends on the context.

Because vor takes the dative case in both of these uses here.

• vor der Untersuchung
• vor der Spritze

Both Untersuchung and Spritze are feminine nouns, and the feminine dative singular article is der.

So:

• die Untersuchung → vor der Untersuchung
• die Spritze → vor der Spritze

German main clauses follow the verb-second rule. The conjugated verb must be in the second position.

If the sentence began with the subject, it would be:

• Ich hatte vor der Untersuchung Angst vor der Spritze.

But since the sentence starts with the time phrase Vor der Untersuchung, the verb still has to stay second:

• Vor der Untersuchung hatte ich Angst vor der Spritze.

That pushes the subject ich after the verb.

German often uses the noun Angst with haben:

• Angst haben vor etwas = to be afraid of something

So:

• Ich hatte Angst vor der Spritze
  literally: I had fear of the injection

German does also have the verb fürchten, but Angst haben vor is very common and natural in everyday language.

Examples:

• Ich habe Angst vor Hunden.
• Sie hatte Angst vor der Prüfung.

Because in German, Angst is a noun, and the normal expression is:

• Angst haben = to be afraid

So you say:

• Ich habe Angst.
• Ich hatte Angst.

Not:

• Ich bin Angst or Ich war Angst ❌

If you want to use sein, you would use an adjective instead:

• Ich war ängstlich. = I was fearful/anxious.

But that is not exactly the same as the standard expression Angst haben.

Yes, der Verband can mean different things depending on context.

Common meanings include:

• bandage / dressing in a medical context
• association / federation / organization in other contexts

In this sentence, because it talks about an examination and a possible injection, der Verband clearly means a bandage or dressing.

Because Einzige is being used as a noun-like word here, not just as an adjective.

• das Einzige = the only thing

In German, nominalized adjectives are capitalized.

Compare:

• das einzige Problem = the only problem
  Here einzige is just an adjective, so it is lowercase.

• das Einzige = the only thing
  Here it stands on its own like a noun, so it is capitalized.

Because here it means the only thing, which is treated as neuter in German.

So the phrase is:

• das Einzige = the only thing

If it referred to a person, the gender could change:

• der Einzige = the only one (male)
• die Einzige = the only one (female)

But in this sentence it refers to the only thing that was necessary, so German uses das Einzige.

This is a very common question.

After words like:

• alles = everything
• nichts = nothing
• etwas = something
• vieles = many things
• das Einzige = the only thing

German often uses was as the relative pronoun.

So:

• das Einzige, was nötig war = the only thing that was necessary

This is standard and natural German.

You may sometimes see other structures in advanced or formal usage, but was is the normal choice here.

Because was nötig war is a relative clause, and in German subordinate clauses send the conjugated verb to the end.

Main clause:

• Der Verband war am Ende das Einzige...

Relative clause:

• ...was nötig war

That is why war comes at the end of that part.

Here am Ende means:

• in the end
• ultimately
• when all was said and done

So:

• aber der Verband war am Ende das Einzige, was nötig war
• but in the end, the bandage was the only thing that was necessary

It does not literally mean only the physical end of something here. It means the final outcome.

German often uses Präteritum for sein and haben, especially in written language and also very often in speech.

So these are very normal:

• Ich hatte Angst.
• Es war nötig.

The perfect forms are possible in some contexts, but usually sound less natural here:

• Ich habe Angst gehabt
• Es ist nötig gewesen

Those are grammatical, but in a sentence like this, hatte and war are the more idiomatic choice.

Yes. That would also be correct.

Compare:

• Vor der Untersuchung hatte ich Angst vor der Spritze...
• Ich hatte vor der Untersuchung Angst vor der Spritze...

The difference is mainly emphasis.

• Starting with Vor der Untersuchung emphasizes the time frame.
• Starting with Ich is more neutral and subject-focused.

Both are grammatical.

Yes.

• die Spritze is the everyday word people commonly use for shot, injection, or even syringe depending on context.
• die Injektion is more technical or medical.

In normal conversation, especially in a sentence about being afraid, Spritze sounds much more natural.

Very literal:

• der Verband = the bandage / dressing
• war = was
• das Einzige = the only thing
• was nötig war = that was necessary

So the structure is basically:

• The bandage was the only thing that was necessary.

Natural English might also say:

• In the end, all I needed was a bandage.

But the German sentence itself is straightforward in structure once you break it down.