A Guide To Endoscopic Decompression For Intermetatarsal Neuromas
Utilizing a #15 blade, make a small 4 mm transverse incision on the dorsal aspect of the interspace delineated by the markings. Pay careful attention not to transect tissue deeper than the dermis. One may achieve protection of the superficial peroneal nerve branches by utilizing blunt dissection with Stevens tenotomy scissors to make the portal deeper between the respective metatarsal heads. Place a metatarsal retractor into the portal and gradually retract the instrument. This causes tension on the transverse intermetatarsal ligament.
Make another incision in the affected webspace in a transverse manner between the dorsal and plantar neurovascular bundles. Deepen the incision with blunt dissection using tenotomy scissors down to the level of the intermetatarsal ligament. Use the elevators to create a channel underneath the transverse intermetatarsal ligament for placement of the cannula. Note that one identifies proper tissue planes by the minimal resistance on the instrument during its placement. After placing the elevator inferior to the transverse intermetatarsal ligament, place dorsal pressure on the instrument to feel the unforgiving rigidity of the transverse intermetatarsal ligament.
At this time, place the oval cannula in the same position beneath the transverse intermetatarsal ligament that the elevator achieved. Remove the obturator and leave the cannula in place. Placement of a 2.7 mm, 30 degree beveled scope allows for visualization on the monitor of the transverse intermetatarsal ligament. One can identify the transverse intermetatarsal ligament’s proximal border and differentiate the ligament from the tissue proximal to it.
At this point, introducing an angled hook blade in the same cannula, one transects the transverse intermetatarsal ligament from proximal to distal into two nice, separate edges. Then endoscopically identify the ligamentous edges, which separate upon placement of further retraction on the intermetatarsal retractor. At this point, one must take photographs. Then place the obturator in the cannula and remove the obturator-cannula instrumentation from the interspace. Reintroduce the elevator into the portal incision. Upon inspection, there should be no evidence of any resistance against the elevator due to the transected intermetatarsal ligament.
Then perform closure of the two incisions. One may use a corticosteroid along with local anesthetic. Dressing occurs in the usual manner. Patients may ambulate immediately after the procedure in a postoperative shoe.
One study has shown that satisfactory results with the endoscopic decompression of intermetatarsal neuroma occur in 88 percent of patients versus 74 percent of patients who underwent neurectomy.4 There have been no serious complications reported as a result of this procedure. Although the learning curve is slightly high, the results produced by endoscopic decompression are far superior to open neurectomy with far fewer complications such as “stump neuroma.”
It is prudent to note that the proper patient selection is key to the success of this minimally invasive procedure. One must always exercise conservative treatment prior to any surgical intervention. However, when non-surgical means fail to alleviate the patient’s complaints and symptoms, endoscopic decompression is advisable.
Dr. Fanous is the President as well as a Fellow and the Co-Scientific Chairman of the Academy of Ambulatory Foot and Ankle Surgery. He is the President and CEO of Advanced Medical Management, a medical consulting firm. Dr. Fanous is a former founder and Director of Podiatric Medical Education and Residency Training Program at Anaheim General Hospital in Anaheim, Calif. He is in private practice in Southern California.