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The Dry Operative Field


Unless a spine surgeon knows how to consistently create a dry operative field they should seek another professional endeavor, rather than spine surgery.  It is simply not possible to perform technically demanding, often microsurgical, procedures without controlling hemorrhage.  The primary means of accomplishing this relate to patient positioning.  Once the patient is appropriately and safely positioned (protection of face and extremities) the next challenge is where to make the incision.  Spine marking and intra-operative imaging serve well for this purpose.  After the incision has been made the surgeon needs to continue with maintaining a dry operative field.  The differentiation of anatomic structures and their adequate visualization then require appropriate magnification and illumination by the surgeon to exercise their hard-earned skills.

Positioning
               

Patient positioning is the first step in achieving a dry operative field for lumbar spine surgery.  The key is to reduce pressure on the patient's abdomen and thus decrease systemic venous pressure with attendant decrease in hemorrhage.  The first knee-chest devices developed did the job but often caused pressure related facial sores, peripheral nerve palsies, etc. and did not allow for bi-plane x-ray monitoring.  The more advanced positioning tables (Jackson frame shown) allow for even morbidly obese patients to be operated upon without being subject to significant abdominal compression.
  

Hemostasis

The lowering of systemic venous pressure and  the optimization of arterial pressure by the anesthesiologist are key parts of any surgical procedure.  Once the incision has been made continuing and careful hemostasis must be maintained to decrease overall blood loss and allow for a dry operative field.  It is a dry operative field which permits fine surgical technique.
 

Courtesy FultonJ: "Harvey Cushing": A Biography, Charles C. Thomas, 1946		 After the introduction of the vacuum tube by DeForest, in 1906, a number of high-frequency cutting devices were manufactured for surgical use.  In 1926 W.T. Bovie, attached to the Harvard Cancer Commission first developed a high frequency cautery device which was first used by neurosurgeon Harvey Cushing on October 1, 1926.
The use of "monopolar" cautery soon became commonplace.  It was Edward Malis who first developed "bipolar" vascular coagulation in 1955.  The subsequent introduction of "non-stick" metal surfaces have further improved this important surgical addendum.
 
Less well known are adjuvant hemostasis control techniques such as the appropriate utilization of powdered gelfoam and thrombin mixtures and other gelled substances.  The combination of powdered gelfoam and thrombin creates a paste which can be topically applied through a syringe and canula to the target area.  Care must be exercised in applying this mixture to cancellous bone so as not to promote emboli.