SNAC & SLAC of the wrist
January 10, 2021 || By : Dr. MhmadFarooq || Hand Surgery
What is SNAC & SLAC of the wrist stands for?
1. SLAC of the wrist:
- SLAC stands for Scaphoid–Lunate Advanced Collapse.
- It has been proposed by Watson and associates to define the progression of degenerative changes secondary to SL (Scapholunate) dissociation.
- There were only 3 stages of SLAC of the wrist identified by Watson, then a recent investigation by Lluch identified five stages of this degenerative.
- Watson scaphoid shift test is used to examine the patient with SLAC of the wrist.
- Clinically:
- Difficulty bearing weight with the hand.
- Pain in region of scapholunate interval.
- Progressive weakness of affected hand.
- Wrist stiffness.
Stages of SLAC of the wrist:
Stages | Degenerative Changes Location |
---|---|
I | Radioscaphoid joint |
II | Scaphocapitate joint |
III | Lunocapitate joint |
IV | Triquetrohamate joint |
V | Radiolunate joint |
Treatment:
Nonoperative:
- In mild disease
- NSAIDs
- wrist splinting
- corticosteroid injections
Operative:
Stage | Procedure |
---|---|
Stage I | – Radial styloidectomy + scaphoid stabilization. – PIN and AIN denervation |
Stage II | – Proximal row corpectomy – Scaphoid excision and Four-corner fusion |
Stage III | – Scaphoid excision and Four-corner fusion – Wrist arthrodesis |
2. SNAC of the wrist:
- SNAC stands for Scaphoid Nonunion Advanced Collapse.
- It’s a characteristic progression of posttraumatic osteoarthrosis that result from Untreated, chronic scaphoid nonunion.
Stages of SNAC:
Stages | Degenerative Changes Location |
---|---|
I | Radioscaphoid joint arthritis |
II | Involvement of Scaphocapitate joint |
III | Lunocapitate joint |
Treatment
Nonoperative:
- Patients with low functioning demands.
Operative:
Stage | Procedure |
---|---|
Stage I | – Radial styloidectomy + scapholunate reduction and stabilization. |
Stage II | – Proximal row corpectomy – Four-corner fusion – Wrist arthrodesis |
Stage III | – Proximal row corpectomy – Four-corner fusion – Wrist arthrodesis |
In stage I, the earliest osteoarthritic changes will differ among SLAC and scaphoid nonunion advanced collapse (SNAC) wrists.
In SLAC of the wrists, osteoarthritis includes the proximal scaphoid and the dorsal rim of the radius.
In SNAC of the wrists, osteoarthritis develops between the distal scaphoid and the radial styloid, while the proximal fragment of the scaphoid remains free of pathology.
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