| # | Column | Type | Notes |
|---|
| 1 | eid | integer | Encoded participant identifier. This identifier is the same encoded id used in the main dataset. |
| 2 | ins_index | integer | Instance index. A numerical index which together with the eid uniquely identifies the corresponding record in the main HESIN table. |
| 3 | arr_index | integer | Array index. A numerical index which together with the eid & ins_index uniquely identifies this record, i.e. eid, ins_index & arr_index together form a primary key for this table. |
| 4 | level | integer, coding 925 | Classification of operation/procedure. |
| 5 | opdate | date | Date of operation. |
| 6 | oper3 | string, coding 259 | Operative procedures - OPCS3. Operative procedures are coded according to the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 3 (OPCS-3). |
| 7 | oper3_nb | string | Operative Procedures - OPCS3 addendum. |
| 8 | oper4 | string, coding 240 | Operative procedures - OPCS4. Operative procedures are coded according to the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 4 (OPCS-4). |
| 9 | oper4_nb | string | Operative Procedures - OPCS4 addendum. |
| 10 | posopdur | integer | Duration of post-operative stay. |
| 11 | preopdur | integer | Duration of pre-operative stay. |
