What pulse is located in the group between the medial malleolus and the Achilles tendon?

Tibial Arteries

The origin of the tibial arteries is identified by extending the incision used to locate the distal popliteal artery. The tibial arteries include the anterior tibial artery and the tibioperoneal trunk, which bifurcates into the peroneal and posterior tibial arteries. Division of the soleus muscle longitudinally helps expose the origin of the tibial arteries. Retracting on the popliteal vein posteriorly helps expose the anterior tibial artery. Retracting the popliteal vein anteriorly helps expose the peroneal and posterior tibial arteries. Exposure of the anterior tibial artery is done through an incision along the middle of the anterior compartment of the leg. The artery is located at the level of the interosseus membrane and can be reached by dissecting between the extension hallucis and the extensor digitorum muscle. Exposure to the distal aspect of peroneal and posterior tibial artery is via a medial incision along the posterior aspect of the tibia and posterior to the medial malleolus. Completion angiography is generally recommended after repair of popliteal and tibial artery injury so that any defects in the repair can be immediately addressed.

How and Where to Inject

Palpate the tibial artery between the medial malleolus and the Achilles tendon (Figures 6-29 and 6-30). After sterile preparation and with aseptic technique, the needle should be inserted just posterior to the tibial artery and angled slightly anteriorly. The needle should be inserted approximately 1–2 cm. At this point, the needle tip should be in the tarsal tunnel and in close proximity to the tibial nerve. Care should be taken to avoid intraneural injection. If paresthesia is elicited (the patient should be warned of this possibility), the needle should be withdrawn slightly. Aspirate before injecting to ensure the needle has not entered a vascular structure. Some physicians use a nerve stimulator to help localize the nerve.

Anterior Tibial Artery

The anterior tibial artery is the smaller terminating branch of the popliteal artery that arises from the lower border of the popliteus muscle. It passes forward through the interosseous membrane into the anterior compartment of the leg. At first, it lies close to the medial aspect of the neck of the fibula, but inclines medially and forward on the membrane as it descends and rests against the anterior surface of the shaft of tibia in the lower third of the leg. It lies deep between anterior tibialis and extensor digitorum longus muscle proximally and extensor hallucis longus muscle distally. In the final part of its course, it is covered only by skin, fascia, and extensor retinaculum. At the level of the ankle, the tendon of the extensor hallucis longus muscle crosses in front of the artery to become medially related. The artery then continues on as the dorsalis pedis.

Throughout the course, the anterior tibial artery is surrounded by two interlacing venae comitantes and the deep peroneal nerve. The deep peroneal nerve, after winding around the neck of the fibula, joins the anterior tibial artery soon after the artery enters the anterior compartment. Initially the nerve lies laterally to the artery, but from about the middle of the leg, the nerve takes up an anterolateral relationship with the artery for the rest of its course.

Vascular Anatomy

The anterior tibial artery emerges from the popliteal artery about 3 cm under the knee joint at the distal border of the popliteus muscle and passes proximal to the interosseous membrane to the extensor site of the lower extremity.107 Then it is running distally in the depth of the extensors compartment lateral to the anterior tibialis muscle. At the level of the upper ankle joint, it becomes more superficial and is crossed by the extensor hallucis longus tendon. Then it passes under the extensor retinaculum, where it ends as dorsalis pedis artery at the dorsum of the foot. Then, 1 to 3 cm below the lower edge of the extensor retinaculum, it gives off two lateral tarsal arteries supplying the extensor brevis muscles. The dorsalis pedis artery is then only covered by the fascia and skin lying laterally from the extensor hallucis longus tendon and profound peroneal nerve and running down to the spatium interosseum I. Here, it gives off the terminal branches, which include the first metatarsal artery and the profound plantar artery—both supplying the first and second metatarsal and toe region communicating to each other. If the dorsal metatarsal artery is lying superficial, it supplies the skin area of two-thirds of the dorsal forefoot. The profound plantar artery also communicates with the plantar arch, which is supplied by the lateral plantar artery and sometimes also to the medial plantar artery, both arising from the posterior tibial artery. The emergence of the metatarsal artery from the dorsalis pedis artery is covered by the extensor hallucis brevis muscle. The concomitant veins accompany the arteries, whereas the superficial venous system that also should be included in the flap arises from the toe in the subcutaneous fat layer at the level of the MTP II joint, draining in the dorsal venous arch and then in the greater saphenous vein. The deep and superficial systems are communicating at nearly every level of the forefoot.

Vessel diameter107:

Dorsalis pedis artery: 2.0 to 3.0 mm

Dorsalis pedis vein: 1.5 to 3.0 mm

Upper lateral tarsal artery: 1.8 mm (at mean)

First dorsal metatarsal artery: 1.0 to 1.5 mm

Greater saphenous vein: 3.0 to 5.0 mm

Dorsal venous arch: 1.2 to 3.3 mm

Pedicle length:

Dorsalis pedis pedicle: 4 to 8 cm

Tibialis anterior pedicle: 7 to 23 cm

Tibial Stents

Stents have been used in the tibial arteries. Balloon-expandable stents were initially the only option since the crossing profile and diameter of self-expanding stents were nonideal for these 2.5- to 3.5-mm arteries. Scheinert et al. compared the use of sirolimus-eluting versus bare metal stents in 60 consecutive patients with infrapopliteal lesions. At 6 months follow-up, the mean degree of in-stent restenosis determined angiographically was 1.8% ± 4.8% in the sirolimus patients (n = 27) versus 53.0% ± 40.9% in the bare metal stent patients (n = 26).94 This preliminary study suggests that DES technology may be beneficial and that balloon-expandable stents may be an acceptable alternative. A 4-Fr self-expanding nitinol stent (Xpert, Abbott Vascular, Redwood City, California) has been evaluated in 35 patients and had a arteriographic primary patency rate of 82% at 6 months95 (Figure 9b-22). Bosiers et al. studied this same stent in 47 CLI patients and report a 12-month arteriographic primary patency rate of 76.3%.96 These intriguing initial results will no doubt lead to further use of stents in the tibial arteries. At present, the use of provisional stenting should be limited to patients with CLI.

Tibioperoneal Stents

The role of provisional versus primary stent placement in tibial arteries is unsettled.63 A recent small randomized trial of PTA compared to PTA with a bare metal stent (BMS) demonstrated no significant differences for 1-year outcomes, including patency rates, limb salvage, or survival64 (Fig. 20-9). Preliminary results of the use of balloon expandable coronary DES in tibial vessels have been reported.14,15,65,66 Smaller series have shown excellent patency when comparing below-knee BMS to DES.67,68 The largest published series is a nonrandomized report of 106 patients (118 limbs) with CLI treated with below-knee DES.15 The 3-year cumulative incidence of amputation was only 6%, and amputation-free survival was 68%.

Anterior tibial artery angiosomes

The anterior tibial artery supplies the anterior aspect of the leg and the dorsalis pedis angiosome of the foot. In the leg, the area overlying the anterior compartment is supplied from the anterior tibial crest to the fibula. Several anastomotic connections are formed just proximal to the level of the ankle joint. As previously described, the anterior medial malleolar artery supplies the tissue overlying the medial malleolus and connects with the posterior tibial source artery. Also at this level, the lateral malleolar artery supplies the tissue overlying the distal extent of the fibula and anastomosis with the anterior perforating branch of the peroneal artery.

Tibial Level Injuries

In penetrating trauma, prompt revascularization for ischemic limbs in tibial artery injury affords excellent results. Revascularization to a single target is sufficient to provide flow to the lower leg. Ligation and/or observation in single-vessel injuries is well tolerated as long as collateral circulation is confirmed before the ligation, preferably by arteriography. Some double artery injuries are well tolerated. However, if the peroneal was the sole remaining artery, revascularization of the anterior or posterior tibial artery is necessary for limb salvage. In blunt trauma, there is a high incidence of limb loss that increases when there is ischemia on presentation.27

Delayed fasciotomy and the need for fasciotomy revision (extension of the incision or opening of a missed compartment) are associated with increased morbidity and mortality. As such, the authors generally perform prophylactic four-compartment fasciotomy of the leg utilizing a two-incision approach for those at risk for compartment syndrome: namely, those patients with prolonged ischemia (>4 hours) before revascularization and severe infrageniculate leg injury (i.e., mangled extremity). The authors also have a low threshold to perform leg fasciotomy in patients who have had ligation of a large extremity venous injury, those who have had hemorrhagic shock requiring significant resuscitation, and those with combined arterial and venous injuries.18 If uncertainty exists about whether or not fasciotomy is indicated at the time of the initial vascular repair, our preference is to proceed with fasciotomy due to the increased morbidity and mortality from delayed fasciotomy.47

Using the two-incision approach, all four compartments can be quickly and safely decompressed. A longitudinal skin incision lateral to the tibia is used to visualize the anterior and lateral compartments. Parallel incisions in the fascia are used to decompress these compartments. The second skin incision is medial and immediately posterior to the tibia. This incision is used to access both posterior compartments (Fig. 15-17). Care must be taken to avoid the superficial peroneal nerve and the saphenous vein. Also, when decompressing the anterior and lateral compartments, the intermuscular septum should be identified to ensure that both compartments have indeed been opened and that one is not misguided by the appearance of the similar muscle groups.

Arterial supply of the flap (see Figures 33.1, 33.2, 33.6)

The blood supply to the great toe pulp and second toe pulp flaps can be either dorsal or plantar dominant, depending on the patient’s anatomy. The dorsal system is dominant in 60% of cases. The dorsal system is technically simpler to dissect than the plantar system, although it can sometimes run deep between the first and second metatarsals, complicating the dissection. The plantar system is slightly more difficult to expose because it lies deeper and plantar foot exposure is more tedious with a patient in supine position.

Below-knee segments

The popliteal artery is followed to its bifurcation and the origin of the anterior tibial artery and then on to the bifurcation of the tibioperoneal trunk. This segment is another site of predilection of disease and careful assessment is required. The posterior tibial and peroneal arteries are best examined from a medial approach; the peroneal artery lies deep to the posterior tibial artery with this approach. The anterior tibial artery is examined from an anterolateral approach as it lies on the interosseous membrane between the tibia and fibula. The peroneal artery may also be seen from this approach. In cases where the calf arteries are difficult to visualise, using power Doppler, or scanning transversely and using the companion veins to identify their location may be of help. This latter approach is facilitated if the patient can sit on the edge of the couch with their leg dependent.

The calf arteries are followed down to the ankle. The pedal arteries are examined if clinically indicated, usually if the dorsalis pedis artery is being considered for a distal graft insertion, or there are particular questions about the arterial circulation in the foot (Fig. 63.14).

For infrapopliteal examinations, patency of the distal anterior tibial, posterior tibial and peroneal arteries is identified. Arteries are described in terms of diameter, patent length with evidence of stenoses, waveform shape and evidence of communication with the pedal arch.

There have been fewer studies reporting on ultrasound scanning of infrapopliteal arteries. In comparison with scanning the proximal arteries, investigation of vessels in the lower leg is time-consuming with a lower reported success rate, especially for peroneal artery stenosis.48,49 The presence of extensive, severe calcification can preclude full investigation of calf arteries; this is a practical constraint on the many patients presenting with diabetes or chronic renal failure (Fig. 63.15). Nevertheless, a study comparing angiography and duplex scanning assessment of vessel patency48 concluded that agreement between the two modalities was similar to agreement between radiologists reporting on angiograms. For these arteries, colour flow is particularly useful for identifying the course of vessels and the presence of collateral flow.

Ultrasound has been shown to be effective in evaluating run-off vessels suitable for femorodistal reconstructions.50 For these preoperative examinations, flow and velocities are often very low indeed. High-frequency transducers are required using low colour and spectral pulse repetition settings.