DEFINITION

Chronic plantar fasciitis with distal tarsal tunnel syndrome is an underrecognized disorder in which the patients with the typical enthesopathy of plantar fasciitis develop neurogenic symptoms and signs,

becoming recalcitrant to the usual management of the initial condition.5

This chapter will concentrate on the most common type of distal tarsal tunnel syndrome: chronic plantar fasciitis associated with the involvement of the lateral plantar nerve and the first branch of the lateral plantar nerve.

 

 

ANATOMY

 

Proximal or classic tarsal tunnel syndrome was first described by Koppell and Thompson15 in 1960. It was

subsequently named by Keck14 and Lam17 in two independent reports in 1962. Entrapment of the entire tibial nerve as it courses beneath the flexor retinaculum behind the medial malleolus defines proximal tarsal tunnel syndrome (FIG 1A). The flexor retinaculum or laciniate ligament is formed by joining the deep and superficial aponeurosis of the leg and it is closely attached to the sheaths of the posterior tibial, flexor digitorum longus, and flexor hallucis tendons.

 

 

 

FIG 1 • A. The laciniate ligament, three branches of the tibial nerve, and the classic tarsal tunnel. B. Detailed anatomy of the tibial nerve and branches.

 

 

Distal tarsal tunnel syndrome, proposed by Heimkes et al13 in 1987, results from irritation of one or more of the terminal branches of the tibial nerve. The three terminal branches are the medial plantar nerve, lateral plantar

nerve, and medical calcaneal nerve.

 

 

The first branch of the lateral plantar nerve occurs just after the lateral plantar nerve branches from the posterior tibial nerve (FIG 1B). The first branch travels between the abductor hallucis muscle deep fascia and the medial fascia of the quadratus plantae muscle. It then changes direction and travels laterally in a horizontal plane between the quadratus plantae and the flexor digitorum brevis muscles, sending a sensory branch to the central heel pad, and terminates as motor branch to the abductor digiti quinti. (The “first branch” may, in some patients, emerge from the tibial nerve itself but then passes under the abductor hallucis

and follows the usual course of the nerve.)6,20

 

The lateral plantar nerve follows the same course initially, passing under the deep fascia of the abductor hallucis and the medial edge of the plantar fascia and over the quadratus plantae fascia, and then turns distally under the flexor digitorum brevis, emerging distally just under the plantar fascia to form the intermetatarsal nerves to the

 

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4/5 interspace and contributing to the 3/4 intermetatarsal nerve as well.

 

 

The medial plantar nerve leaves the tibial nerve just proximal to or just under the abductor hallucis and travels under the abductor hallucis, innervating it and forming the intermetatarsal nerves to the 1/2, 2/3, and 3/4 interspaces. Both the medial and lateral plantar nerves provide innervation to the interossei and lumbricals.

 

The medial calcaneal nerves may be multiple and emerge from the tibial nerve proximal to the proximal (upper) edge of the abductor hallucis. (On occasion, the calcaneal branch(s) may emerge from the tibial under the abductor hallucis, split the fibers of the abductor and its fascia, and then continue subcutaneously to innervate the medial skin of the heel.)

 

The plantar fascia or aponeurosis arises from the os calcis and is composed of three segments—the central, medial, and lateral portions.

 

 

Clinically, the central portion is considered to be the plantar fascia and originates from the medial tuberosity of the os calcis and inserts into all five toes.

 

Extension of the toes and the metatarsophalangeal (MTP) joints tightens the plantar aponeurosis, elevates the longitudinal arch, and inverts the hindfoot. This mechanism, which is entirely passive and depends on bony and ligamentous stability, is referred to as the windlass mechanism.

 

PATHOGENESIS

 

Plantar fasciitis is thought to be a result of repetitive microtearing of the origin of the central band of the plantar aponeurosis.

 

 

This repetitive trauma results in inflammation and persistent pain, especially pain with the first steps in the morning or with the first steps after periods of inactivity.

 

Chronic symptoms of plantar fasciitis develop in about 10% of patients with plantar heel pain.

 

 

We believe that these patients experience partial ruptures or attenuation of the plantar fascia as suggested by clinical findings in which the medial border of the fascia becomes less distinct than the normal side when the ankle and toes are dorsiflexed.6,8

 

A subset of these patients has chronic, disabling plantar heel pain with associated neurogenic symptoms of distal tarsal tunnel syndrome.

 

NATURAL HISTORY

 

In 1986, Rondhuis and Huson20 described compression of the first branch of the lateral plantar nerve and its association with heel pain.

 

Baxter et al1 further studied and reported on the principle of isolated compression of the first branch and its association with chronic plantar fasciitis.

 

Further studies by Lau and Daniels18 demonstrated that increased traction in the lateral plantar nerve and in its first branch is noted as the supporting structures of the longitudinal arch are selectively divided, including the plantar fascia, which could result in a “traction neuritis” of the nerves.

 

Inflammatory conditions and local edema affect the nerve as it travels in the hindfoot. Entrapment, or traction irritation, of the lateral plantar nerve and its first branch is thought to occur between the abductor hallucis muscle deep fascia, the medial border of the plantar fascia, and the medial caudal margin of the quadratus plantae muscle.

 

 

Electrodiagnostic evidence of compression of the first branch lateral plantar nerve and its association with chronic plantar fasciitis have been reported by Schon et al.22

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Patients with chronic proximal plantar fasciitis with distal tarsal tunnel syndrome have signs and symptoms typical of both plantar fasciitis and neuritis.

 

We believe that chronic plantar heel pain that does not respond to a standard nonoperative protocol is the result of attenuated or significant partial plantar fascia rupture, in addition to some degree of neuritis or nerve entrapment.

 

The patient population is diverse, with a wide age range and varied activity levels, and includes both nonathletes and elite competitive athletes. Occupations are also diverse, although many patients are employed in vocations that require prolonged standing or walking.

 

Plantar Fasciitis

 

Plantar fasciitis symptoms are considered chronic when they persist for at least 3 months.6,8

 

 

Typically, symptoms include plantar heel pain that is most severe with the first steps in the morning or with the first steps after prolonged sitting. This pain disappears relatively quickly after walking for a few moments and is relieved immediately upon non-weight bearing. It does not become increasingly painful with increased walking or at rest.

 

On physical examination, there is tenderness at the medial tubercle of the calcaneus, which correlates with the origin of the plantar fascia. This area of tenderness is focal and reproducible and is located at the plantar medial heel.

 

 

Most patients in the chronic state have evidence of attenuation of the plantar fascia and probable biomechanical incompetence.

 

This asymmetry between the two feet in terms of firmness of the plantar fascia is noted when recreating the windlass mechanism (ankle dorsiflexion and first to fifth MTP joint dorsiflexion) and palpating the plantar fascia medial border. This difference is thought to represent a significant chronic partial plantar fascia tear.

 

Significant attenuation of the plantar fascia was noted at preoperative evaluation in 15 of 22 patients in the series reported by DiGiovanni et al.4

Neuritis/Distal Tarsal Tunnel Syndrome

 

Neuritic symptoms and signs may be subtle and not appreciated unless the examiner is aware of their potential presence and checks for their possible existence.

 

Neuritic symptoms typically include reports of a “afterburn” rather than instant relief of heel pain with non-weight bearing after prolonged activity.

 

 

Patients may also describe radiation of pain in the posteromedial ankle, medial hindfoot, and distal plantar foot, often, but not always, with numbness or burning and often worse with prolonged standing or when resting after prolonged activity.

 

Neuritis pain may radiate up the medial aspect of the leg, a condition known as the Valleix phenomenon.

 

 

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Radiation of the neuritic pain may occur along the lateral aspect of the plantar heel, following the course of the lateral plantar nerve first branch. This pain may be experienced in the center of the heel (“central heel pad syndrome”) or along the lateral heel border and also attributable to the first branch or “nerve to the abductor digiti quinti.”

 

In many cases, the patient will have difficulty describing the exact nature of the pain but may report diffuse tingling, burning, or numbness.

 

The medial hindfoot tenderness is located over the abductor hallucis muscle at a position approximately 5 cm anterior to the posterior border of the heel at the intersection of the plantar and medial skin.

 

 

If one palpates the medial border of the heel, the examiner's digit will suddenly feel a “soft spot,” which corresponds with the course of the lateral plantar nerve and its first branch as they pass from the ankle into the foot at the lower edge of the fascia of the abductor hallucis, an area that is associated with nerve entrapment or neuritis.

 

This is a separate area from the medial tubercle of the calcaneus tenderness associated with plantar fasciitis.

 

In athletes (especially basketball players) or individuals whose occupations involve prolonged standing, enlargement or hypertrophy of the abductor hallucis muscle may be appreciated.

 

Patients with such irritation of the tibial nerve and its branches may also be tender over the nerves in the arch, noted with the plantar fascia relaxed by passively plantarflexing the ankle and toes.

 

 

These patients have been diagnosed with so-called distal plantar fasciitis, an entity we doubt exists except with midsubstance ruptures of the plantar fascia.

 

These patients with tarsal tunnel syndrome may also have tenderness in the intermetatarsal spaces, suggesting intermetatarsal neuritis, Morton neuroma, or a “double crush” syndrome. This is usually not the case, however, as patients with primary pathology proximally in the distal tarsal tunnel and plantar fascia complain of heel, arch, and posteromedial ankle pain, whereas those with primary disease distally complain of metatarsal pain (metatarsalgia) and may incidentally also have tenderness over the nerves proximally.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Electrodiagnostic studies are usually performed before surgical intervention, with most aimed at ruling out associated pathology, such as radiculopathy and generalized peripheral neuropathy.

 

 

If diffuse peripheral neuropathy rather than localized nerve entrapment is suspected, screening for diabetes, thyroid dysfunction, or alcoholism may be indicated.

 

Lower extremity electrodiagnostic studies are known to be less reproducible than upper extremity studies and are also dependent on the expertise and skill of the electrodiagnostician in performing detailed foot and ankle studies. The studies should evaluate potential entrapment of both the lateral and medial plantar nerves.

 

Electromyelographic results for the abductor hallucis or abductor digiti quinti are more likely to be abnormal than are nerve conduction studies.21

 

A positive result adds confirmation to the clinical diagnosis, but because the neuritic component is thought to

be a traction neuropathy, as demonstrated by Lau and Daniels,18 and is believed to be most evident in the dynamic situation, which is not usually tested, a negative result does not rule out the diagnosis. Accordingly, it is not uncommon to have negative electrodiagnostic studies despite signs and symptoms of neuritis.

 

Serologic studies may be indicated to evaluate for possible inflammatory arthritis in patients with bilateral heel pain of simultaneous onset and similar severity.

 

Weight-bearing foot radiographs are obtained to rule out such associated pathology as calcaneal stress fracture and hindfoot degenerative joint disease.

 

 

Patients with subtalar and sometimes ankle arthrosis or with tenosynovitis of the posterior tibial, flexor digitorum longus, and flexor hallucis tendons may have sufficient swelling to irritate the tibial nerve.

 

A subset of patients with posterior tibial tendon dysfunction may also have tarsal tunnel symptoms.16

 

If there is a history of previous fracture or significant trauma, radiographs of both the ankle and foot should be obtained to rule out external sources of nerve compression such as exostosis.

 

Computed tomography (CT) has a limited role but may be helpful if there is a prior history of trauma with posttraumatic changes to assess for bony exostosis and deformity.

 

Technetium bone scans have a poor specificity and are rarely indicated.

 

Magnetic resonance imaging (MRI) is sensitive for detecting frank fascial rupture and confirming proximal plantar fasciitis, but it is not indicated in most cases.

 

 

MRI can demonstrate occult pathology, such as a spaceoccupying lesion in the proximal or distal tarsal tunnel or a subtle calcaneal stress fracture.

 

Ultrasonography can be very helpful to determine pathology in the tarsal tunnel, a site of external compression or changes in the size and character of the nerve in the area of compression or traction.19

 

DIFFERENTIAL DIAGNOSIS

Diffuse peripheral neuropathy (diabetes mellitus, thyroid dysfunction, alcoholism) Lumbar radiculopathy

Inflammatory arthritis

Calcaneal stress fracture, hindfoot degenerative joint disease

 

 

NONOPERATIVE MANAGEMENT

 

Initial nonoperative treatment includes relative rest, plantar fascia and Achilles tendon stretching exercises, ice, and nonsteroidal anti-inflammatory drugs.

 

Physical therapy modalities that involve or promote heating of the tissues, such as whirlpool baths, hydrocollator

packs, diathermy, ultrasound, or phonophoresis, seem to irritate the neuritic symptoms and increase rather than decrease symptoms.

 

 

Iontophoresis, which diffuses steroid with electrolysis, is well tolerated and is worthwhile.

 

Steroid injections into the plantar fascia or the nerve itself are discouraged.

 

 

Many patients present with a history of earlier episodes of plantar fasciitis that responded to steroid injections.

 

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These patients are now unresponsive to injection and have an obviously attenuated plantar fascia. This suggests an association of steroid injection with plantar fascia rupture and the ensuing chronicity.

 

Inexpensive over-the-counter orthotics are prescribed to support the arch and cushion the heel. With chronicity, a semirigid, accommodative, custom orthotic is prescribed. These are cork based and triple layered and include a “nerve relief channel” made of viscoelastic polymer, which is placed along the path of the lateral plantar nerve

beginning at the proximal abductor hallucis muscle belly and extending to the soft spot.11

 

 

If the patient has more symptoms in the central heal pad, which involves the first branch of the lateral plantar, the channel is carried more posteriorly and onto the plantar heel to include the painful central area.

 

The same orthotic devices are used postoperatively if the patient requires surgery.

 

Preliminary studies with extracorporeal shock wave lithotripsy (ESWL), of both low and high intensity, for chronic plantar fasciitis report a positive response and the modality appears to be safe and effective.

 

 

For individuals with chronic plantar fasciitis and associated signs and symptoms of neuritis, however, ESWL was not as effective. The treatment has the potential to further aggravate the inflamed nerves and is therefore not recommended.

 

Controlled ESWL studies in which patients with neurogenic symptoms were excluded had better results. Additional investigations are needed to clarify these issues.

 

SURGICAL MANAGEMENT

 

In the late 1980s and early 90s, Baxter and colleagues1 reported on and popularized their surgical approach to painful heel syndrome in athletes with entrapment of the first branch of the lateral plantar nerve. This approach includes partial release of the plantar fascia combined with release of the first branch of the lateral plantar nerve and removal of a heel spur if present. The investigators have reported a high success rate, particularly in the athletic population.

 

 

More recent reports using this approach in a more general patient population have noted mixed results,

however, with Davies et al2 in 1999 reporting less than 50% of patients with complete satisfaction as a result of persistent symptoms.

 

DiGiovanni and colleagues3,4 have devised and reported on a modified surgical approach based partially on the

work of Baxter and colleagues.1 The approach is also based on the observation that patients with plantar fascia rupture and chronic pain who do not have neurogenic symptoms respond to a complete surgical release of the plantar fascia.

 

 

Patients who had the release described by Baxter et al1 and continued to be symptomatic responded to the complete release and neurolysis as described in the following text.

 

The more extensile approach is used to allow the release of all potential sources of entrapment of the tibial

nerve and its branches and thus allow for improved rates of complete resolution of pain and elimination of activity limitations.

 

This technique combines a complete plantar fascia release with a proximal and distal tarsal tunnel release, without bone spur removal.

 

The philosophy behind a complete release rather than a partial release of the plantar fascia is as follows:

 

 

The literature does not provide information about the optimal amount of partial release to perform to allow for reproducible resolution of plantar heel pain. The amount is probably highly variable from patient to patient and depends on a number of factors, including the type of foot arch.

 

Patients with chronic heel pain commonly have evidence of attenuation of their plantar fascia and probably have preexisting biomechanical incompetence. A further partial release in feet with preexisting plantar fascia attenuation has not consistently led to resolution of plantar heel symptoms.

 

Complete release of the plantar fascia from the abductor hallucis to the abductor digiti quinti has consistently relieved the pain experienced after the first step in the morning or after recumbence.

 

The nerve component of the pathology is also specifically addressed. In our experience, release of the plantar fascia alone in patients with chronic plantar fasciitis often leads to increased neuritic symptoms. Consequently, the nerve procedure is always performed in addition to the plantar fascia release.

 

 

Rather than an isolated release of the first branch of the lateral plantar nerve, a proximal (or classic) as well as a distal tarsal tunnel release is performed to address all potential sites of nerve entrapment.

 

 

Proximal tarsal tunnel syndrome may coexist with distal and can be difficult to differentiate and isolate. In addition, more than one branch of the terminal tibial nerve branches may be entrapped.

Preoperative Planning

 

Good history taking, specifically to determine when and in which anatomic location symptoms occur, is essential. We cannot emphasize enough that the history will differentiate metatarsalgia, pure plantar fasciitis, radiculopathy, and neuropathy.

 

A careful physical examination must be done as indicated previously.

 

Electrodiagnostic testing is useful when the history and physical have not clearly ruled out neuropathy particularly or radiculopathy.

 

 

Tibial nerve entrapment may coexist with neuropathy, but the prognosis for a good result with this surgery is guarded, and we believe such a combination accounts for less than optimal results.

 

Positioning

 

The patient is positioned supine without a bump under the hip, allowing the leg to externally rotate.

 

Multiple folded surgical towels are placed under the foot to allow the surgeon to easily operate posteromedially and to allow room for the assistant to retract. The foot is positioned near the foot of the table, but not at the end, so the surgeon has the table on which to rest the forearms and not be forced to operate in midair.

 

 

P.4623

 

We operate from the seated position across the normal leg and use a rolling surgical stool so that we can move from facing the medial side to the plantar side.

 

 

When we move around to the plantar side, we ask the anesthetist to place the foot of the bed in

Trendelenburg to improve access.

 

Approach

 

We use a posteromedial and plantar approach to fully visualize the anatomy.

 

 

The procedure is done with high thigh tourniquet control after exsanguination of the leg. Bipolar cautery is used for minimal tissue necrosis.

 

There are circumstances when division of the abductor hallucis is required—abnormal or confusing anatomy and bleeding from small vessels. Consequently, a unipolar cautery with grounding is always in place to use in the cutting mode and vessel ligation clips of small and medium size are available in the operating room.

 

Loupe magnification is always used, with a preference of 3.5 to 4.5 magnification.

 

TECHNIQUES

• Complete Release of the Plantar Fascia and Tarsal Tunnel5

   

  The midpoint between the posterior border of the medial malleolus and the medial border of the Achilles tendon is marked. The medial edge of the heel is palpated beginning posteriorly and moving distally until the palpating finger feels the soft spot where the neurovascular bundle enters the foot, and this point is marked as well.

   

   

   

  TECH FIG 1 • A. The skin incision for the complete release. B. Dividing the laciniate ligament. C. Dividing the entire plantar fascia. D. Dividing the deep fascia of the abductor hallucis. E. The abductor hallucis and flexor digitorum brevis interval. F. Lateral plantar nerve overlying the quadratus plantae fascia.

   

   

  The midpoint of the malleolar-tendon interval is marked proximally, and the incision extends plantarward and curves distally to cross the soft spot, continuing onto the plantar skin at the distal portion of the heel pad, and extending transversely about three quarters of the width of the heel skin (TECH FIG 1A).

   

  P.4624

   

  The entire skin incision is made following the skin marking.

   

  The proximal subcutaneous tissue is separated bluntly to identify the superficial vessels, and a double skin hook is placed on the far side of the surgeon and lifted away from the ankle.

   

  The surgeon easily spreads, cuts, and cauterizes superficial vessels and identifies the flexor retinaculum (laciniate ligament). This layer is divided directly over visible posterior tibial veins distally to the level of the abductor hallucis muscle. No attempt is made to isolate the tibial nerve (TECH FIG 1B).

   

  The superficial fascia of the abductor hallucis is divided sharply with a no. 15 surgical scalpel or no. 64 Beaver blade.

   

  The hooks are now moved distally to the plantar surface and spreading and cutting is done with a long-handled tenotomy scissors down to the plantar fascia. Two sharp Senn retractors are now used, which gather the fat away from the fascia and improve visualization.

   

  A Meyerding retractor is placed at the distal extent of the incision to expose the fascia overlying the abductor digiti quinti fascia. The knife blade is used to sharply cut the plantar fascia from its lateral extent, at the edge of the abductor digiti quinti fascia medially to the abductor hallucis fascia, fully exposing the flexor digitorum brevis muscle (TECH FIG 1C).

   

  The plantar fascia surface is actually convex and meets each of the abductor fascias more deeply or dorsally than at its midpoint.

   

  As right-handed surgeons, we release this deep fascia on the right foot from the laciniate ligament distally. On the left foot, we begin from the plantar fascia side. In either case, we now place a self-retaining retractor in the wound to allow the assistant to help with the next step (TECH FIG 1D).

   

  The blades of the tenotomy scissors are spread between the muscle of the abductor hallucis and its deep fascia to initiate its exposure. The Meyerding retractor is used to further tease the muscle off the fascia and enhance and complete its visualization.

   

  The fascia is divided under the muscle, exposing the neurovascular structures and the tarsal tunnel. We divide the deep fascia as far as we can see it and then expose the structure from the opposite side (either proximally or distally) and complete the release.

   

  The muscle of the flexor digitorum brevis is then retracted laterally, and the fine fascia overlying the neurovascular structures is divided.

   

  The interval between the abductor hallucis and the flexor brevis is then exposed. The self-retaining retractor is placed on the skin and subcutaneous fat at this interval. One Meyerding (or similar right angle) retractor is placed under the abductor muscle, retracting it proximally. Another right angle retracts the flexor digitorum brevis laterally (TECH FIG 1E).

   

  The posterior tibial artery and veins are easily seen. Parallel to them but slightly more anterior is the lateral plantar nerve, often with a little fat around it. The whiteness of the nerve and its striations make it obvious. The first branch is not specifically exposed but lies more posteriorly.

   

  The nerve is carefully teased from its surrounding tissues and gently retracted and the underlying quadratus plantae fascia is observed.

   

  A small vessel may obscure visualization of the nerve in some patients. In such cases, with the power of the bipolar cautery turned down, we carefully cauterize and cut it to provide the needed exposure.

   

  The quadratus fascia is often a dense band over which the nerve is obviously tented. In other cases, the white bands of fascia are visible but less dense. They are cut sharply with the scissors to expose the muscle. The nerve now lies under no tension (TECH FIG 1F).

   

  With the confluence of the superficial and deep abductor fascias distally and the medial border of the plantar fascia, a dense band of fascia overlies the lateral plantar nerve, and with the dense band of the quadratus fascia below, it is easy to visualize a pincer effect on the nerve at this point with weight bearing and particularly when the plantar fascia is less taut.

   

  Closure is carried out after irrigation of the wound. The ankle subcutaneous is closed with 4-0 absorbable suture and the skin with 4-0 nonabsorbable suture. The glabrous plantar skin is closed with only 3-0 or 4-0 skin permanent suture using locking horizontal mattress sutures, with no subcutaneous suture.

   

  A soft bulky dressing is applied and the tourniquet released. Sterility is not broken until the toes show good perfusion.

• Complete Plantar Fascia and Tarsal Tunnel Release for Prior Incomplete and Failed

  Releases9

   

   

  The same basic approach is used as just described but with several additions to the technique. The new incision begins proximal to the original one to start in normal tissue.

   

  The old incision is incorporated into the new, ensuring access to the soft spot.

   

  When the laciniate ligament is divided, the tibial nerve is exposed and a vessel loop is placed around the nerve and a tie is placed on the loop as opposed to a hemostat to avoid any traction on the nerve.

   

  As the release proceeds, external neurolysis of the tibial nerve and of the medial and lateral plantar branches is carried out. The calcaneal nerves are identified and protected. The first branch of the lateral plantar nerve is identified.

   

  The muscle belly of the abductor hallucis is often divided with a cutting cautery with careful blunt dissection to protect the underlying critical structures. The muscle of the flexor digitorum brevis may also be partially or fully divided to get adequate exposure.

   

  If there is no evidence of damage to the nerves or marked wound scar or scar around the nerves, the wounds are closed as in the primary procedure.

   

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• Complete Plantar Fascia and Tarsal Tunnel Release When Extensive Scarring of the Nerve is Present, with the Use of Barrier Wrapping of the Nerve

   

  The complete release as described earlier is performed.

   

  For nearly 20 years, we have used greater saphenous vein wrapping of scarred mixed nerves that must be preserved. More recently, we have used barrier wrapping with commercially available collagen tubes. Both techniques are described in the following text.

  Use of the Greater Saphenous Vein

   

  The greater saphenous vein is harvested with a longitudinal incision beginning in the midpoint between the crest of the tibia and its posteromedial margin. One usually has to harvest a length of vein three times the length of nerve to be wrapped.

   

  At harvest, metal ligaclips are used for the branches, which are few in number in the distal vein. Double medium clips are used at either end of the vein, and one is left on the proximal end of the harvested proximal vein to indicate the orientation of the vein.

   

  The vein is placed in lidocaine to relax the smooth muscle component. It is then dilated from distal to proximal either with mechanical dilators or hydrostatically with lidocaine inserted under pressure with a syringe, using a vein plastic adaptor fitted to the syringe.

   

  All metal clips are then removed and the vein divided longitudinally.

   

  The vein is then curled around the involved nerve in barber pole fashion with the venous intima adjacent to the nerve. The vein is wrapped without tension, and each end is attached to surrounding tissues so as not to have a closed loop at either end. The coils are attached to each other with two 7-0 Prolene sutures placed about 180 degrees apart (TECH FIG 2).

   

  The medial and lateral plantar nerves are wrapped separately.

   

  The tibial nerve may be wrapped and then the surgeon may continue down one or the other of the branches.

   

   

   

  TECH FIG 2 • A. Vein wrapping. B. Bovine collagen longitudinally split tubes for wrapping.

   

   

  The wrap of the other plantar nerve joins the initially wrapped portion.

   

  The first branch of the lateral plantar may be initially wrapped with the lateral plantar and then allowed to travel independently distally.

   

  The calcaneal branches are allowed to escape between the coils and must not be entrapped in the procedure.

  Use of Commercial Collagen Tubes9

   

  Use of the commercially available collagen tubes simplifies the process. The tubes come in diameters ranging from 2 to 10 mm and lengths of 2.5 to 5 cm. The tubes are provided longitudinally divided.

   

  The size to be used is determined by the surgeon's estimation of the needed diameter and lengths. Several lengths may be joined or a slightly long segment may be trimmed.

   

  The slit in the tube is closed, not too tightly, with a few interrupted 6-0 nylon sutures. Some of the commercially available wraps have enough material overlap to obviate the need for any suturing.

• Use of Conduits for Neuromas of the Calcaneal Branches7,10,12,23

   

   

  A neuroma of a calcaneal branch is treated with either a vein or a collagen conduit. The neuroma is exposed and excised.

   

  A conduit of at least 2 cm should be used. (Bovine collagen conduits are 2.5 cm in length and start at the

  2.0 mm diameter with availabilities of increasing diameters at 0.5 mm increments.)

   

  Collagen tubes of a proper diameter to loosely enclose the nerve are available, and the 5 cm lengths may be trimmed as needed.

   

  When using a vein, the diameter must also be large enough to loosely accommodate the nerve, and the lumen diameter may need to be narrowed a bit so that it fits a little more closely around the nerve end.

   

  A nylon suture is placed through the end of the nerve, the needle is removed, and the two ends of the suture are grasped with a hemostat.

   

  A suture passer (Hewson) is placed through the conduit, and the nylon suture attached to the nerve is placed through the suture passer loop.

   

  The conduit is slid over the nerve, overlapping by 5 mm to 1 cm, and 8-0 sutures are used to attach the conduit lumen to the epineurium of the nerve. Typically, two sutures at 180 degrees are placed. The nylon suture used to draw the nerve into the conduit is removed (TECH FIG 3).

   

  The nerve and its “conduit to nowhere” is buried posteromedially, often into the retrocalcaneal space.

   

   

  P.4626

   

   

   

  TECH FIG 3 • A. Vein conduits. B. Bovine collagen conduits for neuromas (or nerve guide for repairs).

• Case Example (Courtesy of Mark E. Easley, MD)

Combined Proximal and Distal Tarsal Tunnel Release

 

Approach for both proximal and distal tarsal tunnel release

 

Oblique vertical incision over posteromedial foot and ankle (TECH FIG 4A)

 

Avoid transverse incision (for plantar fascia release), which may injure superficial medial calcaneal branches.

 

 

 

TECH FIG 4 • A. Oblique vertical incision for proximal and distal tarsal tunnel release. B. With the flexor retinaculum released, tibial nerve branches exposed. C. Superficial medial calcaneal branch identified. Medial calcaneal branches may be injured if transverse incision has been traditionally used for plantar fascia release. D,E. Medial and lateral tibial nerve branching. F. Distal tarsal tunnel exposed to release deep fascia of the abductor hallucis muscle. Note the plantar fascia immediately plantar to the inferior margin of the deep abductor hallucis fascia.

 

 

 

Exposure for tarsal tunnel release: Release the flexor retinaculum.

 

Tibial nerve branches exposed (TECH FIG 4B-F)

 

 

Distal Tarsal Tunnel and Partial Plantar Fascia Release Oblique incision over posteromedial foot (TECH FIG 5A) Release the superficial fascia over abductor hallucis muscle.

 

Expose the abductor hallucis muscle (TECH FIG 5B,C).

 

Release the deep fascia of abductor hallucis muscle.

 

The tibial nerve branches course directly under this fascia.

 

 

A tight deep fascia creates compression on the nerve branches.

 

 

A complete release of the deep fascia is important.

 

 

Any residual intact fibers of the deep fascia may continue to create nerve compression. A potential error is to incompletely release the most distal fascia fibers.

 

P.4627

 

Retract the abductor muscle inferiorly to expose the superior aspect of the deep fascia (TECH FIG 5D).

 

 

 

TECH FIG 5 • A. Approach for distal tarsal tunnel and plantar fascia. With superficial abductor hallucis fascia release, the abductor muscle is exposed. B,C. A 4- to 5-cm oblique incision is made over the posteromedial heel. D. With plantar retraction of the abductor muscle, the superior aspect of the deep fascia is exposed. E. With dorsal retraction, the inferior aspect of the deep fascia is exposed. It is important to release the entire deep abductor fascia so that no residual bands compress the nerves. F. Release of the superior aspect of the deep fascia. G. With elevation of the abductor muscle, the inferior aspect of the completed superior release of deep abductor hallucis fascia is identified. H. The inferior deep fascia is released, directly extending from the identified completed portion of the deep fascia release. I. Completed deep abductor hallucis fascia release. Note that immediately plantar to the inferior border of the deep fascia lies the medial border of the plantar fascia. J. Note neurovascular structures exposed with release of the deep abductor hallucis fascia.

 

 

 

Retract the abductor muscle superiorly to expose the inferior aspect of the deep fascia (TECH FIG 5E). First, release the superior aspect of the deep fascia (TECH FIG 5F).

 

Retract the abductor muscle superiorly to identify the inferior aspect of the completed superior release of deep fascia (TECH FIG 5G).

 

P.4628

Complete the inferior release of the deep fascia (TECH FIG 5H).

With complete release, the tibial nerve branches are typically decompressed (TECH FIG 5I,J).

Partial Plantar Fascia Release

Immediately inferior to the inferior border of the deep abductor hallucis fascia is the medial border of the plantar fascia (TECH FIG 6A).

 

TECH FIG 6 • A. Medial border of plantar fascia is identified. B. Medial plantar fascia partial resection. C. A section of plantar fascia is released to ensure that the medial plantar fascia cannot reconstitute.

Relax the medial plantar fascia.

A section of medial plantar fascia is resected to take tension off of the tight and most symptomatic aspect of the plantar fascia (TECH FIG 6B,C).

Avoid complete release of the plantar fascia for plantar fasciitis. With loss of the plantar fascia support to the arch, lateral foot symptoms may develop.

 

 

 

 

PEARLS AND PITFALLS

 

Indications ▪ It is essential that the patient's history is compatible with the diagnosis and that he or she is tender or has a Tinel sign at the soft spot.

• If the history and physical examination do not correlate, look elsewhere for the diagnosis.

 

Accuracy of the skin incision

• The skin incision must be accurate and the anatomy clearly seen.

• If the entrance of the neurovascular bundle to the foot is not accurately located, the release will be unsuccessful.

• If there is difficulty finding the nerve in the interval between the abductor and the flexor brevis, divide the muscle of the abductor hallucis and find the nerve more proximally and follow it through the interval.

• If you are lost, find the nerve under the laciniate ligament (it is posterior to the vessels and more lateral) and follow it and the lateral plantar branch more distally to carry out a proper release.

   

  Bleeding

  • Use of loupes and careful hemostasis will prevent bleeding, which prevents accurate visualization of the structures.

  • Postoperative bleeding will irritate the nerve and create more scarring and can compromise the result.

  • Make sure the tourniquet is of proper size for the size of the thigh, and exsanguination must be right up to the tourniquet. This may necessitate the use of

 

Completeness ▪ All structures noted in the description must be fully released. of the release

a sterile tourniquet applied after draping. At times, with a very obese thigh, a

double width or two tourniquets in succession may be helpful or a calf tourniquet may be used.

• We cannot emphasize enough the importance of excellent visualization of the anatomy.

 

 

POSTOPERATIVE CARE

 

The patient is placed in a soft bulky dressing at surgery, and crutches are used for non-weight bearing. From immediately after the operation, motion of the foot and ankle is encouraged.

 

Sutures are removed at 2 weeks and a light dressing is applied. Gentle range-of-motion exercise of the ankle is reemphasized to promote gliding of the nerve but non-weight bearing continues for 2 more weeks.

 

At 4 weeks, the patient is allowed to bear weight using the custom orthotic described earlier.

 

 

The orthotic is used for at least 9 months and then may be phased out.

 

If the patient fails to comply, pain will be experienced, usually on the dorsum and lateral border of the foot, presumably from “arch strain.” Most patients comply, without too much encouragement.

 

 

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OUTCOMES

Primary Surgery

DiGiovanni et al3,4 reported an 82% rate of total satisfaction in primary surgery patients, with a marked decrease in pain to a level of no pain or mild, intermittent pain. This is a significant improvement over the less than 50% total satisfaction reported in most recent studies of limited plantar fascia release with a limited nerve release or nerve release without plantar fascia release.

The improved rate of total satisfaction is reflective of the lower rates of residual pain and activity limitations. Improved surgical results in primary surgery patients are thought to be due to the comprehensive surgical approach with the goal of addressing all potential sites of pathology—nerve and plantar fascia.

Our unreported data from more than 100 cases followed for over 2 years indicate that patients take varying periods of time to reach a steady state or complete relief of all symptoms. This averaged about 18 months and varied from 6 months to 2.5 years (Hollis et al, unpublished data, 2005).

The surgical technique described here is highly recommended in patients with chronic plantar fasciitis and neuritic signs and symptoms, without prior surgery.

Revision Surgery

Less predictable results have been reported for revision surgery. Although 73% of patients indicated they were better off than before surgery, total satisfaction was reported by only 27% and 36% were dissatisfied with the procedure. There was a much higher incidence of residual pain and activity limitation.

In revision situations, patients with evidence of inadequate prior distal tarsal tunnel release and those with persistent mechanical plantar fasciitis are most likely to have good resolution of their symptoms.

Although the results for barrier wrapping and of the use of conduits for neuromas are less certain than those for the primary releases, they are still superior to results for other techniques reported to date. Data on the use of collagen conduits and wraps are being collected, with encouraging early outcomes.

 

 

COMPLICATIONS

A low rate of complications, both intraoperatively and postoperatively, can be expected with this technique.

Meticulous technique is needed to avoid potential complications, which include wound dehiscence, perineural scarring, and direct nerve injury. We recommend using bipolar electrocautery and surgical loupe magnification.

Development of complex regional pain syndrome is possible postoperatively. Early diagnosis and aggressive treatment improve the prognosis.

 

 

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2. Davies MS, Weiss GA, Saxby TS. Plantar fasciitis: how successful is surgical intervention? Foot Ankle Int 1999;20:803-807.

    

    

3. DiGiovanni BF, Abuzzahab FS, Gould JS. Plantar fascia release with proximal and distal tarsal tunnel release: surgical approach to chronic, disabling plantar fasciitis with associated nerve pain. Tech Foot Ankle Surg 2003;2:254-261.

    

    

4. DiGiovanni BF, Rodriguez del Rio FA, Gould JS. Chronic, disabling heel pain with associated nerve pain: primary and revision surgery results. Podium presentation and abstract at the 17th Annual Summer Meeting of the American Orthopaedic Foot and Ankle Society, July 19-21, 2001, San Diego, CA.

    

    

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