A Closer Look At Endoscopic Plantar Fasciotomy

Prior to the development of the first endoscopic foot surgery, there was a strong desire not only to find a better, less invasive method to treat recalcitrant mechanical plantar fasciitis surgically but also to develop a more universally consistent surgical approach to what has been labeled an “endemic problem.” Indeed, the standard of care regarding the surgical management of the heel pain has radically changed since the introduction of the endoscopic plantar fasciotomy (EPF).
In 1990, there was an almost universal perception within the podiatric community that the spur was the primary cause of plantar fasciitis and any successful surgery must address that cause.1 Some literature solely supported doing a plantar fasciotomy without resecting the inferior calcaneal exostosis.2 However, the majority of published articles on this complex topic involved something in addition to a fasciotomy, like resecting the inferior calcaneal exostosis, resecting “heel neuromas,” decompressing the first branch of the lateral plantar nerve or denerving the medial calcaneal nerve.2-8
After cadaveric investigation, researchers performed the first series of endoscopic plantar fasciotomies with a one portal system called “The Inside Job,” which was designed by Agee for carpal tunnel release.9 The manufacturer quickly recalled this system, due to reports of nerves being transected and incomplete release of the carpal ligament, which ended our investigation with this device.10
This instrument recall led to the development of the two-portal techniques, specifically designed for endoscopic plantar fasciotomy, a procedure which is still in widespread use today.11 We learned early on that we could adequately release the fascia via an endoscopic approach. In using this approach, we found that patients responded with less pain and made a quicker return to regular shoes and activity than those patients who had undergone traditional open techniques.

The Evolution Of The Two-Portal Technique
Given the high degree of patient satisfaction with the less invasive, endoscopic approach, there was strong motivation to develop another endoscopic technique. This led to the development of the Barrett-Day two-portal approach, which proved to be advantageous over the one-portal technique in many ways.
First, the two-portal procedure allowed for better visualization of the anatomical structures. It also had a smaller diameter so it was less traumatic than the one-portal system. Most importantly, far more surgeons have been able to achieve successful results in using the two-portal approach. This is evidenced now by the fact that more than 500,000 EPFs have been performed since the two-portal procedure was granted FDA approval in 1992.12
The two-portal EPF technique has certainly evolved over the years. Initially, it was believed that you had to perform significant physiological lengthening of the plantar fascia in order to resolve the patient’s symptoms. Our initial study demonstrated a very high efficacy in resolving heel pain, but it also revealed a nearly 10 percent incidence of complications.13 Primarily referred to as lateral column destabilization phenomena, these symptoms could include pain in the sinus tarsi, peroneal tenosynovitis, pain in the calcaneal cuboid joint or just a generalized pain throughout the lateral column of the foot.
The data from the study indicated that when you cut the plantar fascia, it lost much of its stabilizing forces until it healed, albeit in a lengthened position. Clinically, some of these cases proved difficult to treat and for some patients, the complication seemed worse than the patient’s initial heel complaint. Certainly, this was not satisfactory, even in light of the overwhelming majority of success with the technique.
The procedure evolved to the point where we only cut part of the fascia. Clinically, there was no loss of surgical efficacy but we did notice a significant reduction in lateral column problems. Much of what we saw in this early series of patients has now been demonstrated in biomechanical, cadaveric experiments.14-16
Over the next two years, the standard of care centered on cutting only the medial one-third of the plantar fascia. Quantification of fascial dimensions indicated that you needed to release 13.5 mm of fascia, on average, in order to achieve a medial one-third fasciotomy. The instrumentation was subsequently modified to reflect these measurements, with intra-cannular markings to guide the surgeon during the technique.

Defusing The Controversy Over Lateral Column Complications
EPF initially proved to be very controversial in both the podiatric and orthopedic communities. There was much debate on why there was a higher rate of lateral column complications with the endoscopic technique as opposed to the open approach. Surgeons also questioned why so many endoscopies were being performed compared to open techniques.
There is overwhelming clinical evidence that the reason behind the higher complication rate was the simple fact that patients who underwent EPF were up and on their feet much quicker than the open group. Biomechanically, there should be no other logical explanation. After all, surgeons cut fascia the same with the open technique, if not more, than with the endoscopic approach.
However, the immediate postoperative morbidity associated with the more traumatic open technique kept people off of their feet during those first three to six weeks after their surgeries. This timeframe proved critical because until the fascia healed back together (usually by the eighth week), the foot was biomechanically unstable and therefore more susceptible to destabilization with a technique that allowed more and earlier ambulation.
While some biomechanical theories suggest it is a continual stretch to the ligamentous structure of the calcaneal cuboid articulation or a stress of the long and short plantar ligaments, we really do not know the etiology of pain in the lateral column, particularly at the level of the calcaneal cuboid joint.13-15
If you go with the theory that the etiology is solely related to stress of ligamentous structures, then there should be a point in time when the ligament stretches to an endpoint and the pain ceases. This has not been the case in many of these clinical situations. It is my theory that there is some intraarticular derangement within the calcaneal cuboid joint that causes the continued pain, and could involve an intraarticular labrum as well.17
Theoretically, patients who are more likely to develop this condition after plantar fasciotomy may have one of these intraarticular anatomical structures, or have a larger one. If this is ever proven to be the case, then we might have a way to treat this condition with an arthroscopic evacuation of the calcaneal cuboid articulation, and may eventually come up with a preoperative diagnostic test.
This complex biomechanical scenario has led to the most radical changes associated with EPF and that is the way we manage people postoperatively. When we cut less fascia and the patient reduces stressful activity during the first four to six weeks after surgery, researchers have found there is almost complete resolution of the problematic lateral column destabilization.

Addressing The Debate Over The Increasing Volume Of EPF Procedures
Then there was the debate over why so many EPF procedures were being performed—especially in light of the number of open heel surgeries that were being done nationally. Some alleged there was “a rape of the plantar fascia,” and the increase in numbers was due to unscrupulous and injudicious use of the technique by some practitioners.18 In retrospect, some of that could be true. However, it appears that several factors (including the demand of patients who refuse a more traumatic technique) will increase DPM use of the EPF procedure.
Yet this may be true for any less invasive advancement in a surgical technique. One can draw an analogy with coronary angioplasty. There were several reasons behind the rapid, exponential growth in this technique after it was introduced. More surgeons were trained in the procedure and consequently performed more of the procedures. Patients were much more willing to undergo this type of surgery in comparison to open heart bypass surgery. One can make the argument that there was overutilization of this procedure as well.
When large numbers of surgeons were first implementing the endoscopic technique on a large scale nationwide, there was concern about surgical efficacy and a lack of conservative care attempts prior to surgical intervention. I have always recommended a thorough regimen of conservative care, which includes biomechanical control, non-steroidal management, judicious use of corticosteroid injections, stretching and ice. It is clinically evident that there is a high success rate with this type of care.
I have always believed there are only two reasons why an EPF would fail. First, there was the possibility the surgeon made an intraoperative error. This scenario was plausible in the early part of the learning curve with this technique but rarely could be a valid theory in the hands of an experienced endoscopist. It is more likely something else was contributing to the symptom complex. Perhaps a coexisting or subclinical pathology could be present. I have put forth the acronym MEHPS, which stands for “multiple etiology heel pain syndrome.”20

How The Pressure Specified Sensory Device Can Help
Within the last several years, a new type of technology called the Pressure Specified Sensory Device or PSSD (Sensory Management Services, Baltimore, Md.), has become available. Developed by A. Lee Dellon, MD, a Professor of Plastic and Neurosurgery at the Johns Hopkins University Medical School, this innovative device allows you to perform quantitative assessment of isolated peripheral nerves.
With this device, you can now determine if there is any type of entrapment of the medial calcaneal nerve, which is not to be confused with Baxter’s nerve. (Baxter’s nerve, often described as the first branch of the lateral plantar nerve, was originally described by Roegholt in 1940.4,5) Baxter’s nerve originates from the motor branches of the lateral plantar nerve and innervates the periosteum of the calcaneus.21 Therefore, this nerve cannot cause sensory loss in the heel.
While the EMG and NCV are considered the gold standards of neurology, they cannot evaluate this isolated nerve. However, if you use the PSSD, it is possible for you to evaluate this nerve alone as well as in conjunction with the medial plantar nerve, which is involved with tarsal tunnel syndrome.
In his recent article, Weber pointed out that in carpal tunnel syndrome cases, the NCV studies can be falsely negative up to 40 percent of the time.22 Tassler and Dellon showed in 26 cases of tarsal tunnel syndrome, only 17 had positive electrodiagnostic studies with the NCV. In contrast, all 26 cases reported abnormal with the PSSD test.23 This scenario was very frustrating clinically for those trying to manage complex heel pain disorders. Patients would often complain of nebulous and vague symptomatology yet their electrodiagnostic studies would come back as normal.
With better assessment available for evaluating isolated peripheral nerves like the medial calcaneal and the medial plantar nerve, you now have the ability to see the level (if any) of neurological pathology in the patient who has complex, recalcitrant heel pain. This is important because with clinical experience, many of the coexisting neural etiologies you can now pick up with this technology were previously impossible to discern in some clinical situations. Clinical experience, combined with the recent use of this technology, leads me to believe a slight but significant percentage of patients may have very definite mechanical plantar fasciitis and also have a concomitant peripheral nerve entrapment.24
There have been some reported cases in which patients underwent the EPF procedure and still complained of heel or arch pain. However, sometimes close questioning of these patients would reveal that their original type of heel pain was different than their current heel pain. Often, it is impossible for the patient, as well as the treating physician, to discern one type of pain from another.
What was the likely biomechanical scenario in this situation? These patients may have had a subclinical, occult tarsal tunnel syndrome. Once the surgeon released the plantar fascia, these patients would have more pronation in their feet, causing further entrapment of the medial and lateral plantar nerves. It may also be the case that with the multiple etiology of the heel pain, once the fascial component of their pain was resolved, it allowed for recognition of the neural pain.

Final Thoughts
While the endoscopic plantar fasciotomy has become a well-recognized surgical technique with documented efficacy for treating recalcitrant mechanical plantar fasciitis, you should not use this procedure until you’ve exhausted all conserative care measures and ruled out all other possible etiologies for the patient’s heel pain.23, 25, 26
Still, in addition to providing the patient with a less invasive intervention for surgical treatment of recalcitrant heel pain, the EPF may be a catalyst for re-examining this complex pathology from a profession-wide perspective. n

Dr. Barrett is a Fellow of the American College of Foot and Ankle Surgeons and is board-certified in podiatric orthopedics. He is the Director of Surgical Training at the Institute for Peripheral Nerve Surgery and is the Research Director for the Houston Podiatric Foundation.

For related articles on treating heel pain, check out the November 2001 issue of Podiatry Today in the archives of www.podiatrytoday.com.

References:

References
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11. Barrett, SL. United States Patent #5269290 Instratek, Inc., Houston, TX. Statistics based on sale of EPF instruments.

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13. Thordarson DB, et. al., Effect of partial versus complete plantar fasciotomy on the windlass mechanism. Foot Ankle Int. Vol. 18, #1/Jan 1997.

14. Murphy AG, et. al., Biomechanical consequences of sequential plantar fascia release. Foot Ankle Int. Vol. 19, #3/March, 1999.

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16. Barrett SL, et al. Endoscopic heel anatomy: analysis of 200 fresh frozen specimens. J. Foot Ankle Surg. 34:51-56, 1995.

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18. Weil LS, The rape of the plantar fascia. Biomechanics 1994; 1:37.

19. Barrett SL, MEHPS: Multiple etiology heel pain syndrome. Oklahoma Podiatric Medical Assoc. Fall 2001 Scientific seminar. Monkey Island, OK. Oct. 4, 2001.

20. Dellon AL, Kin J, Spaulding CM, Variations in the origin of the medial calcaneal nerve. JAPMA 92#2:97-101. Feb. 2002

21. Weber RA, et al. A prospective blinded evaluation of nerve conduction velocity versus pressure specified sensory testing in carpal tunnel syndrome. Annals Plast. Surg. 45#3:252-257 Sept. 2000.

22. Tassler PL, Dellon AL, Pressure perception in the normal lower extremity and in the tarsal tunnel syndrome. Muscle Nerve 1996; 19:285-289.

23. Tomczak RL, Haverstock BD. A retrospective comparison of endoscopic plantar fasciotomy to open plantar fasciotomy with heel spur resection for chronic plantar fasciitis/heel spur syndrome. J Foot Ankle Surg. 34:305-311, 1995.

24. Dellon AL. Deciding When Heel Pain Is Of Neural Origin. J Foot Ankl Surg. Vol. 40 (5), 2001, 341-345.

25. Kinley S, et al Endoscopic plantar fasciotomy versus traditional heel spur surgery: A prospective study. J Foot Ankle Surg. 32:6, 595-603, 1993.

26. Shapiro SL, Endoscopic plantar fasciotomy for the treatment of intractable heel pain. American Orthopedic Foot and Ankle Society, 1998 Annual summer meeting.