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- Percutaneous Fixation:
    - in the report by Bond CD, et al (2001), the authors evaluated 25 patients with acute nondisplaced fracture of scaphoid waist that consented to be
           randomized to either cast immobilization or fixation with a percutaneous cannulated screw fixation;
           - 11 patients were randomized to percutaneous cannulated screw fixation, and 14 were randomized to cast immobilization;
           - technical considerations:
                 - it is essential that the guide wire remain centrally locally in the distal fracture fragment on the AP, lateral, and oblique views; 
                 - dorsal approach: 
                        - volar flex wrist;
                        - guide wire is inserted in central third of scaphoid;
                        - aim striaght for scaphoid tubercle;
                        - structures at risk: posterior interosseous nerve, to extensor digitorum communis to the index, and to extensor indicis proprius;
                        - references: 
                               - A technical note on percutaneous scaphoid fixation using a hybrid technique.
                               - Percutaneous Fixation of the Scaphoid Through a Dorsal Approach: An Anatomic Study
                               - Dorsal Minimal Incision Scaphoid Fixation
                               - Complications in Dorsal Percutaneous Cannulated Screw Fixation of Nondisplaced Scaphoid Waist Fractures
                               - Internal fixation of acute, nondisplaced scaphoid waist fractures via a limited dorsal approach: an assessment of radiographic and functional outcomes.
                 - volar approach: the trapezium will tend to block the path of the guide wire away from the ideal path; 
                        - by extending the supiated wrist and by applying traction on the thumb, the trapezium will be translated dorsal to the scaphoid, which allows proper insertion of the guide wire; 
                        - references:
                                    - A Comparison of 2 Methods for Scaphoid Central Screw Placement From a Volar Approach
                                    - Optimization of volar percutaneous screw fixation for scaphoid waist fractures using traction, positioning, imaging, and an angiocatheter guide.
                                    - AO foundation - percutaneous screw fixation
                                    - Incidence of scaphotrapezial arthritis following volar percutaneous fixation of nondisplaced scaphoid waist fractures using a transtrapezial approach.                                     
                 - screw length:
                             - use a second guide wire to measure off of the intraosseous guide wire;
                             - subtract 4-6 mm from measured depth gauge length (screw needs to miss the distal cortex by 2-3 mm and needs
                                         to be countersunk by 2 mm);
- Outcomes:
           - average time to fracture union in the screw fixation group was 7 weeks compared with twelve weeks in the cast immobilization group; (p = 0.0003).
           - average time until the patients returned to work was 8 weeks compared with 15 weeks in the cast immobilization group (p = 0.0001);
           - there was no significant difference in the range of motion of the wrist or in grip strength at the two-year follow-up evaluation;
           - percutaneous cannulated screw fixation of nondisplaced scaphoid fractures resulted in faster radiographic union and return to work compared with cast immobilization 

             

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Percutaneous Screw Fixation or Cast Immobilization for Nondisplaced Scaphoid Fractures  

Percutaneous screw fixation for unstable scaphoid fractures.

Anthropometry of the human scaphoid 

Central placement of the screw in simulated fractures of the scaphoid waist: a biomechanical study.

Central screw placement in percutaneous screw scaphoid fixation: a cadaveric comparison of proximal and distal techniques.