The ergonomics of hydrodissection in cataract surgery
First Author: N.Maqsood UK
Co Author(s): M. Arjunan C. Vize
Correct orientation of the syringe and cannula is vitally important when performing hydrodissection allowing for ease of disassembly and removal of the lens nucleus. Recent design alterations by a widely used syringe manufacturer inadvertently rotated the barrel flange by ninety degrees. With the luer lock securely in place, the alignment of the needle end has the flange at a horizontal rather than vertical position. The result was the necessity to inject in either a supine or prone position restricting wrist movement. This prompted a review of the importance of wrist position, kinematics and the ergonomics of microsurgical instruments.
Hull Royal Infirmary - Eye Hospital.
A review of literature involving wrist kinematics.
Our review of kinematics literature confirmed our suspicions that the needle cannot be aligned in a position of functionality (with the wrist in the vertical meridian) reducing both carpal stability and the load the wrist can handle. Collectively this increases the risk of dropping the syringe.
Evolutionarily humans have developed a tripod grasp during infancy to neutrally position the wrist thus allowing maximum comfortable movement in all directions. The art of modern day cataract surgery relies on purposeful micro-movements including efficient hydrodissection. Cataract surgery has a small margin for error and in a technically demanding procedure such as this, where the success of each sequential step is paramount, consistency of microsurgical instrument design is vital as there is no room for the possibility of reduced wrist stability and an incomplete hydrodissection.