diff --git a/src/aind_data_schema/core/procedures.py b/src/aind_data_schema/core/procedures.py
index 54f2c280e..6c6a7717f 100644
--- a/src/aind_data_schema/core/procedures.py
+++ b/src/aind_data_schema/core/procedures.py
@@ -361,20 +361,18 @@ class Headframe(DataModel):
     well_type: Optional[str] = Field(default=None, title="Well type")
 
 
-class ProtectiveMaterialReplacement(DataModel):
-    """Description of a protective material replacement procedure in preparation for ephys recording"""
+class GroundWireImplant(DataModel):
+    """Ground wire implant procedure"""
 
-    procedure_type: Literal["Ground wire"] = "Ground wire"
-    protocol_id: str = Field(..., title="Protocol ID", description="DOI for protocols.io")
-    protective_material: ProtectiveMaterial = Field(
-        ..., title="Protective material", description="New material being applied"
+    procedure_type: Literal["Ground wire implant"] = "Ground wire implant"
+    ground_electrode_location: MouseAnatomicalStructure.ONE_OF = Field(..., title="Location of ground electrode")
+
+    ground_wire_hole: Optional[int] = Field(
+        default=None, title="Ground wire hole", description="For SHIELD implants, the hole number for the ground wire"
     )
-    ground_wire_hole: Optional[int] = Field(default=None, title="Ground wire hole")
     ground_wire_material: Optional[GroundWireMaterial] = Field(default=None, title="Ground wire material")
     ground_wire_diameter: Optional[Decimal] = Field(default=None, title="Ground wire diameter")
     ground_wire_diameter_unit: Optional[SizeUnit] = Field(default=None, title="Ground wire diameter unit")
-    well_part_number: Optional[str] = Field(default=None, title="Well part number")
-    well_type: Optional[str] = Field(default=None, title="Well type")
 
 
 class TarsVirusIdentifiers(DataModel):
@@ -622,8 +620,6 @@ class MyomatrixContact(DataModel):
 
 class MyomatrixThread(DataModel):
     """Description of a thread of a myomatrix array"""
-
-    ground_electrode_location: MouseAnatomicalStructure.BODY_PARTS = Field(..., title="Location of ground electrode")
     contacts: List[MyomatrixContact] = Field(..., title="Contacts")
 
 
@@ -631,6 +627,7 @@ class MyomatrixInsertion(DataModel):
     """Description of a Myomatrix array insertion for EMG"""
 
     procedure_type: Literal["Myomatrix_Insertion"] = "Myomatrix_Insertion"
+    ground_electrode: GroundWireImplant = Field(..., title="Ground electrode")
     protocol_id: str = Field(..., title="Protocol ID", description="DOI for protocols.io")
     myomatrix_array: MyomatrixArray = Field(..., title="Myomatrix array")
     threads: List[MyomatrixThread] = Field(..., title="Array threads")
@@ -689,7 +686,6 @@ class Surgery(DataModel):
                 NanojectInjection,
                 OtherSubjectProcedure,
                 Perfusion,
-                ProtectiveMaterialReplacement,
                 RetroOrbitalInjection,
                 SampleCollection,
             ],