D-COMPASS – educational calculator

Input data

1. Patient and safety context

Age

BMI

ASA

Wound class

Suspected mesh infection

2. D — Defect geometry, position, and content

Hernia type

Location

Previous recurrences

Defect width [cm]

Defect length [cm]

Number of defects

Total scar / weakened-zone length [cm]Used for incisional or recurrent reconstruction length.

Full reconstruction-zone width [cm]Optional. Use when the weakened area is wider than the fascial opening.

Full reconstruction-zone length [cm]Optional. Overrides defect length when larger.

Overlap rule used by the calculator: primary defect ≤4 cm → 3 cm; any incisional/recurrent defect or primary defect >4 cm up to 12 cm → 5 cm; defect width >12 cm → 7 cm. A primary defect between 4 and 5 cm therefore belongs to the 5 cm category.

Transverse position relative to the midline and semilunar lines

Use a signed centre offset: right = positive, left = negative. Distances from defect edges to semilunar lines may be entered directly or calculated from linea alba and rectus widths. Negative values mean the defect crosses the semilunar line.

Defect centre offset from midline [cm]

Linea alba width [cm]

Left rectus width [cm]

Right rectus width [cm]

Left defect edge → left semilunar line [cm]Optional direct measurement; overrides calculated value.

Right defect edge → right semilunar line [cm]Optional direct measurement; overrides calculated value.

Sac, deformity, reduction, and loss of domain

Sac size

External wall deformity

Reduction of sac contents

Loss of domain [%]

Abdominal capacity after reduction

3. C — Closure feasibility

Anticipated fascial closure after reduction

Posterior layer closure

4. P — Available space for the complete calculated mesh

Enter the available distance from the reconstruction-field edge to the boundary of each pocket. The calculator compares every direction with the required overlap. Missing values reduce confidence rather than being treated as sufficient.

Preperitoneal pocket — available overlap [cm]

Left

Right

Cranial

Caudal

Retrorectus pocket — available overlap [cm]

Left/right values are taken from the semilunar-line measurements above. Enter only the vertical limits here.

Cranial

Caudal

5. A — External reconstruction requirements

Skin / soft-tissue excess

Abdominal wall / soft-tissue loss

Abdominal wall plasty or tissue resection is required

6. S — Expected implant stability

Will the mesh lie completely flat?

Will the mesh be enclosed in a closed plane?

Risk of displacement

Clear

Editable thresholds are in $RULES. The main logic is in calculateDCompass(). Plane selection is performed in the required sequence: preperitoneal → retrorectus → unilateral TAR → bilateral TAR.