Understanding And Managing Equinus Deformities
Since exact precision is required for ideal anatomical placement of the endoscopic instrumentation in any endoscopic surgical technique to afford maximum outcomes, there are a couple of pearls that can aid the surgeon. In a 2005 publication, we presented results from a cadaveric anatomic study of 28 embalmed specimens.15 We were able to describe an “endoscopic zone” for proper placement of the cannula for an endoscopic gastrocnemius recession. It should be noted that in contrast to endoscopic decompression of intermetatarsal nerves and endoscopic plantar fasciotomy, there is more latitude for placement of the endoscopic gastrocnemius recession instrumentation while still being able to perform the procedure successfully.16-19
The surgical technique should begin with appreciation of the topical anatomy with palpation of the “edge” of the medial aspect of the gastrocnemius aponeurosis on the medial aspect of the calf within the “endoscopic zone.” This is where one should place the medial portal incision. Separation with blunt dissection of the subcutaneous fat allows the surgeon to palpate the dense tissue of the aponeurosis.
Usually, there is minimal (2 to 5 mm) subcutaneous fat between the dermis and this tissue plane. In some patients, there is virtually no subcutaneous tissue and the passage of the instrumentation feels like it is just below the skin. After establishing this surgical plane, one can use an elevator to separate the subcutaneous fat from the superficial surface of the aponeurosis.
Performing this step judiciously facilitates maximum protection of the sural nerve from injury. However, the surgeon must take caution as nerve injury can occur even with the most exact and refined surgical technique. Considering that this is only a cutaneous nerve with a small amount of innervation, and that it is the biopsy and donor nerve of choice, the risk is relatively small in comparison to the maximal benefit of improvement in biomechanics for the patient.
True sural nerve injury occurs only rarely, almost always without any sequelae except for “numbness,” but the patient can end up with an amputation neuroma, which could require revision surgery. Neuropraxia of the sural nerve is common. However, due to the subsequent traction of the sural nerve with the increased range of dorsiflexion, this is almost always transient and fades within six to eight weeks.
Once you have placed the instrumentation, it is recommended to begin the transection of the aponeurosis from medial to lateral as there is often only a need for a medial one-third release to reach the desired level of dorsiflexion. If more tissue is required to be cut, it can be based on the intraoperative assessment by the surgeon. Many times, in severe cases, it has been my experience that a complete medial to lateral release is needed.
Essential Postoperative Pearls
The postoperative management of the endoscopic gastrocnemius recession technique is subordinate to the extent required by other simultaneously performed procedures. If one only performs an isolated endoscopic gastrocnemius recession, then patients can immediately bear weight in a tall walking boot. Encourage the patient to remove the boot and perform gentle active movement of the ankle, foot and lower leg. Casting or other complete immobilization is not recommended as this could increase the possible development of a deep venous thrombosis.
Within the last two years, my postoperative regimen includes the use of an intermittent compression and cooling device, which has greatly reduced postoperative edema and discomfort. Preferably, one should have the patient using the device the day of surgery. The endoscopic gastrocnemius recession is usually a minimally painful procedure if one performs it properly.