Dorsal intercalated segment instability

Dorsal intercalated segment instability (DISI) is a form of instability involving the wrist. It occurs mainly after the disruption of the scapholunate ligament. It is more often encountered than volar intercalated segment instability (VISI).

Fixed DISI deformity only occurs after combined injury of scapholunate ligament and other stabilizers of the scaphoid, namely radioscaphocapitate and scaphocapitate ligaments.

On an AP view, the normal trapezoidal configuration of the scaphoid may be lost and it may appear triangular.

On the lateral radiograph with the wrist in neutral position, DISI typically shows a dorsal tilt of the lunate with both of the following present:

On sagittal CT, the same findings as on plain radiograph are seen.

On sagittal MRI 9, the same findings as on plain radiograph are seen. However, bone contusion, scaphoid avascular necrosis and scapholunate ligament injury are evaluated with more precision.

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Article information

rID: 9709
Tag: wrist
Synonyms or Alternate Spellings:
  • DISI
  • DISI deformity
  • Dorsiflexed intercalated segment instability
  • Dorsal intercalated segmental instability

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Cases and figures

  • Figure 1
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  • Case 1
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  • Figure 2
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  • Case 2: following scaphoid fracture
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  • Figure 3
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  • Case 3
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  • Case 4
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