If you set up a table of values to use for the second value list, you can set up the standard FileMaker conditional value list.
The table would have at least two fields, Procedures and Materials such as:
Procedure | Material
Breast Implants | First Material
Breast Implants | 2nd Material
and so forth
Then you need a relationship:
LayoutTableOccurrence::Procedure = Materials::Procedure
Where "layoutTableOccurrence" is the name of the table occurrence on which you base your layout, or possibly a portal and "Materials" is the above table.
You can then set up a use values from field value list listing values from the Material Field in Materials and select the "Include only related values, starting from LayoutTableOccurrence" to use as your conditional value list on a materials field in the LayoutTable.
There are actually a number of different ways to set up a conditional value list and there are a number of alternative value selection techniques that can go beyond what can be done with a conditional value list.
Here's a demo file of different Conditional Value Lists. Each one is documented in great detail to explain how it is set up and how it works.
In that file, you'll find a link to Adventures in FileMaking #2 - Enhanced Value Selection that demonstrates methods for selecting values in ways not possible with a simple value list.