Indications for felon incision and drainage
Felon incision and drainage is required for infection and abscess located in the pads of the fingertips.
Streptococcal infections – these generally are treated with antibiotics
Cellulitis with abscess of localized prurulent collection.
History and physical – this is important as the severity and extent of the infection can be partially determined by the precipitating event and duration and location of the infection.
When planning a felon incision and drainage, it must be remembered that infections in the volar surface (i.e., palm side) of the hand and finger somewhat paradoxically usually present with impressive swelling in the dorsal surface (i.e., back side). Incisions are only made in the dorsal surface if there is actual fluctuance appreciated.
Plain radiographs (X-rays) – these are sometimes obtained to check for the presence of air in the finger tissues that might indicate anaerobic bacteria are involved requiring felon incision and drainage.
Computed tomography (CT) – this is done rarely to ascertain proximal involvement of the abscess when planning felon incision and drainage.
Magnetic resonance imaging (MRI) – this test is extremely useful in diagnosis and treatment of hand conditions, including abscesses and infection and is the gold standard in imaging modalities of the hand. MRIs of the hand do not require contrast media. Surgeons planning felon abscess and drainage usually like to order this scan if possible.
Preoperative Work-up and Preparation
Antibiotics – On an outpatient basis, Augmentin is commonly prescribed as it has a broad-spectrum antibiotic coverage. Bactrim is used on an outpatient basis in suspected cases of MRSA. Intravenous antibiotics used include cefazoling (Ancef) and vancomycin.
Elevation and immobilization – this strategy is adopted before felon incision and drainage if the infection has not completely formed a definable collection.
Glucose control – this is paramount in diabetics as it is difficult to clear infections if the patients are hyperglycemic (high serum glucose.)
Felon drainage is typically done under regional or local blocks. Regional blocks may be done at the level of the brachial plexus or the axillary nerve. Wrist blocks may be done at the level of the radial nerve (for the thumb and forefinger), ulnar nerve (for the ring and 5th finger) and the median nerve.
Digitabl blocks can be carried out for the affected finger but should be performed in the web space on either side of the affected finger, never at the base. Injections at the base of the finger risks ischemia of the digit due to the inability of the tissues to expand to hold the volume of injection.
Surgical Details of Procedure
1. The involved hand is washed with soap and water and all gross dirt and grease is removed.
2. Some surgeons doing this incision and drainage strive for a bloodless field by elevating the hand until the venous system has been drained and then applying a forearm tourniquet.
3. If the abscess is superficial a No. 15 scalpel is used to make and incision over the involved area.
4. For deeper abscesses an L-shaped incision is made along one side of the nail and then across the fingertip and parallel to the end of the nail.
5. Vigilance must be used to fully enter the abscess cavity but to avoid entering the tendon sheath to prevent dissemination of the infection proximally through this anatomic space.
6. The wound is packed with small gauze wicks and allowed to remain open to drain.