6 Hand Infections

10.1055/b-0038-161074

6 Hand Infections

Dariush Nikkhah

6.1 Flexor Sheath Infection

Flexor sheath infections are heralded by Kanavel’s signs: fusiform swelling, flexed posture to digit, pain over flexor sheath, and pain on passive extension (Fig. 6‑1). These infections should be treated with emergent washout to avoid chronic hand dysfunction and in severe cases amputation.

Fig. 6.1 Classical presentation of a flexor sheath infection in the ring finger. Grossly swollen digit with foreign body puncture wound.

Early presentations without subcutaneous purulence can be washed with a closed technique and can be given intravenous antibiotics. Later presentations with subcutaneous purulence may need to be managed with an open approach using broad midlateral flaps to prevent flap necrosis.

6.2 Flexor Sheath Washout

Once the flexor sheath is opened proximally, a green cannula with the metallic introducer is placed underneath the A1 pulley. The introducer maintains rigidity and prevents kinking of the plastic sheath. Sometimes due to swelling it is necessary to vent the A1 pulley to gain access. Distal access is made through the A5 pulley. If the surgeon remains midline, neurovascular structures will remain safe (Fig. 6‑2, Fig. 6‑3, Fig. 6‑4, Fig. 6‑5).

Fig. 6.2 **(a,b)** Markings over A1 and A5 pulley for closed irrigation technique and blunt dissection down to A1 pulley and flexor sheath.

Fig. 6.3 Flexor sheath opened over A1 pulley. Pus identified and swabbed for microbiology to determine antibiotic sensitivities.

Fig. 6.4 Blunt dissection down to A5 pulley for distal access of flexor sheath, care here not to injure the digital nerves as they can be very superficial.

Fig. 6.5 A green cannula with a metallic introducer is used to irrigate from the A1 to A5 pulley. The “fountain sign” can be seen with saline coming out from the A5 pulley.

It is also important to lift the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) with a tendon hook to break up loculations and adhesions particularly if the patient is returning to theater for a second debridement (Fig. 6‑6).

Fig. 6.6 Often in flexor sheath infections the FDS and FDP tendons become adherent and the surgeon must lift them up to break up loculations and adhesions. This helps facilitate closed catheter irrigation. The green cannula can also be placed between the FDS and FDP tendons for closed catheter irrigation.

In cases where there is subcutaneous purulence or a closed technique has failed to improve the infection, an open approach is advised (Fig. 6‑7, Fig. 6‑8). Flaps should be kept broad to prevent tip necrosis and tendon exposure. A midlateral incision has a key advantage over a Bruner-type incision as the flap can cover the flexor tendons when the wounds are left open. Bruner flaps need to be at least tacked together to prevent retraction and tendon exposure.

Fig. 6.7 **(a,b)** Midlateral open approach is warranted in cases where there is subcutaneous purulence over the entire digit.

Fig. 6.8 **(a,b)** Similar case demonstrating severe flexor sheath infection with subcutaneous purulence. There is obliteration of the annular pulleys. A closed technique would not address the infection.

Wounds should be left open and dressed with Betadine-soaked gauze over Jelonet and a plaster of Paris in the position of safe immobilization (Fig. 6‑9, Fig. 6‑10). The injured hand should be placed in a high-arm sling to reduce edema.