Eric Stuffmann and Jeffrey Yao
DEFINITION
Deep space infections occur in one of three anatomically defined potential spaces within the hand—the thenar, midpalmar, and hypothenar spaces—or in one forearm potential space, Parona’s space.
Thenar space infections are the most common deep space infections. Midpalmar and hypothenar space infections are much more rare.
Deep space infections usually result from direct penetrating trauma or spread from an adjacent infection such as a superficial abscess or a flexor tenosynovitis (in the case of thenar and midpalmar space infections).
The single most common infecting organism is Staphylococcus aureus, although most of these infections are mixed.
ANATOMY
The thenar space (FIG 1) is defined by the fascia of the adductor pollicis muscle dorsally and the tendon sheath of the index finger and palmar fascia volarly.
The radial border is defined by the insertion of the adductor pollicis tendon and fascia on the thumb proximal phalanx.
The ulnar border is the midpalmar (oblique) septum, which extends from the third metacarpal to the palmar fascia.
The midpalmar space (see FIG 1) is bordered radially by the midpalmar septum and bordered ulnarly by the hypothenar septum, which extends from the fifth metacarpal to the palmar fascia.
The dorsal border of the midpalmar space is the fascia of the second and third palmar interosseous muscles, and the volar border is the flexor sheaths of the long, ring, and small fingers and the palmar fascia.
FIG 1 • Cross-sectional anatomy of the hand demonstrating the deep spaces.
The hypothenar space (FIG 1) is bordered radially by the hypothenar septum and dorsally by the periosteum of the fifth metacarpal. The fascia of the hypothenar muscles forms the ulnar and palmar borders.
Parona’s space is a deep potential space in the distal forearm superficial to pronator quadratus and deep to the flexor digitorum profundus tendons. It is continuous with the midpalmar space.
PATHOGENESIS
Thenar space infections may result from penetrating injury or local spread from adjacent flexor tenosynovitis or a subcutaneous abscess.
If not treated early, the infection may spread to the dorsal side of the hand after destroying the fascia of the adductor pollicis muscles and traveling between the transverse and oblique heads.
Midpalmar space infections usually result from direct penetrating trauma, but may also result from spread of an adjacent flexor tenosynovitis or superficial abscess.
Hypothenar space infections usually result from direct penetrating trauma, but may also result from spread of a superficial abscess.
Parona’s space infection may result from direct penetrating trauma, in which case the infection may be isolated to Parona’s space.
Infection involving Parona’s space may also result from contiguous spread from a ruptured radial or ulnar bursae (FIG 2). The end result will be involvement of the midpalmer space and a horseshoe abscess (FIG 3).
FIG 2 • Radial and ulnar bursae may communicate in the distal volar forearm (Parona’s space).
FIG 3 • Drawing representing the clinical appearance of a horseshoe abscess.
PATIENT HISTORY AND PHYSICAL FINDINGS
The patient may recall a history of a penetrating injury in the vicinity of the involved deep space.
In the case of a thenar space infection, the patient will present with swelling and tenderness in the thenar region.
The patient will hold the thumb in an abducted position to minimize the pressure for comfort.
If the infection has been present for some time, it may have spread dorsally, in which case swelling and tenderness will be found dorsally in the first web space.
In the case of a midpalmar space infection there will be tenderness and swelling in the midpalm, although dorsal swelling may be more impressive due to the strength of the palmar aponeurosis.
The fingers will be held in a semiflexed posture.
This condition is distinguished from flexor tenosynovitis by relative lack of pain with passive motion of the fingers and with direct palpation of the flexor sheath along the digit.
Infection of Parona’s space is characterized by swelling in the distal volar forearm and pain with digital flexion.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Radiographs should be obtained in all cases to rule out the presence of foreign bodies.
Radiographs also may reveal underlying osteomyelitis in the setting of more chronic infections.
Patients suspected to have systemic illness should have an appropriate laboratory workup.
DIFFERENTIAL DIAGNOSIS
Thenar space infection
Midpalmar space infection
Hypothenar space infection
Flexor tenosynovitis
Superficial abscess
Osteomyelitis
NONOPERATIVE MANAGEMENT
There is no role for nonoperative treatment in the setting of deep space infections.
Antibiotics should be avoided until adequate cultures can be obtained, unless the patient is systemically ill and there will be a forced delay in operative treatment.
SURGICAL MANAGEMENT
Drainage of deep space infections should be carried out in the operating room under general anesthesia.
Gram stain and cultures for aerobes, anaerobes, mycobacteria, and fungi should be obtained intraoperatively just before IV antibiotics are administered.
Thorough irrigation with 6 to 9 L of normal saline should be performed.
All nonviable tissue must be débrided sharply.
Surgical wounds may be closed very loosely over a drain if all necrotic tissue has been thoroughly débrided.
If there is any doubt, the wound should be left open to heal by secondary intention using wet-to-dry dressing changes and soaks.
In very severe cases, a second irrigation 48 to 72 hours later may be required.
Positioning
The patient is positioned supine with a standard hand table and nonsterile tourniquet.
Approach
Drainage of thenar space infections can be performed through a volar incision or a dorsal longitudinal incision (or, sometimes, both).
A volar incision involves risk to the recurrent motor branch of the median nerve, the digital nerves to the thumb and index finger, the princeps pollicis artery, and the proper digital arteries.
A volar incision also allows concomitant treatment of a thumb septic flexor tenosynovitis.
A dorsal longitudinal incision avoids the painful scar associated with a volar incision.
Drainage of midpalmar space infections may be performed through a transverse skin incision in, or parallel to, the distal palmar crease over the third and fourth metacarpals.
Alternatively, a curved longitudinal incision may be used.
Hypothenar space infections are approached through an incision in line with the ulnar border of the ring finger extending from 3 cm distal to the wrist crease to just proximal to the midpalmar crease.
Parona’s space may be approached through a longitudinal incision just ulnar to the palmaris longus.
Alternatively, a trans–flexor carpi radialis approach may be used. Parona’s space
TECHNIQUES
INCISION AND DRAINAGE OF THENAR SPACE INFECTIONS
In the case of a volar approach, make an incision just adjacent and parallel to the thenar crease, beginning 1 cm proximal to the web space and extending 3 to 4 cm proximally (TECH FIG 1A).
After blunt dissection through the palmar fascia, the digital nerves to the thumb and index finger, the princeps pollicis artery, the proper digital arteries, and the recurrent motor branch of the median nerve are encountered (TECH FIG 1B,C).
The abscess will lie superficial to the adductor pollicis muscle.
Dissection should then continue dorsally over the distal edge of the adductor muscle to decompress any dorsal extension of the abscess.
Alternatively, a thenar space infection may be approached dorsally through a longitudinal incision (TECH FIG 1D).
The dorsal incision may be straight or slightly curved and should bisect the space between the first and second metacarpals.
Dissection should be carried down to the interval between the first dorsal interosseous muscle and adductor pollicis muscle, where the purulence will be encountered.
Thoroughly débride all necrotic tissue, and irrigate copiously with sterile saline.
Place a strip of packing strip gauze into the open wound to allow for drainage, and dress the wound appropriately.
TECH FIG 1 • A. Thenar incision. B,C. Neurovascular bundle. D. Alternative dorsal incision for drainage of thenar abscess.
INCISION AND DRAINAGE OF MIDPALMAR SPACE INFECTIONS
Make a transverse incision parallel to or in the distal palmar crease over the third and fourth metacarpals (TECH FIG 2A).
Alternatively, a curved longitudinal incision may be used (TECH FIG 2B).
Bluntly dissect to either side of the flexor tendons to the ring or middle finger, where the abscess will be encountered.
Protect the neurovascular bundles, which lie on either side of the tendons (TECH FIG 2C).
Thoroughly débride all necrotic tissue, and irrigate copiously with sterile saline.
Place a strip of packing strip gauze into the open wound to allow for drainage, and dress the wound appropriately.
TECH FIG 2 • A. Transverse incision for drainage of midpalmar abscess. B. Curved longitudinal incision for drainage of midpalmar abscess. C. Drainage of midplanar abscess (neurovascular bundle protected by freer).
INCISION AND DRAINAGE OF HYPOTHENAR SPACE INFECTIONS
Make an incision in line with the ulnar border of the ring finger extending from just proximal to the midpalmar crease to 3 cm distal to the wrist crease (TECH FIG 3A).
Incise the hypothenar fascia in line with the skin incision, and the purulence will be encountered (TECH FIG 3B).
Thoroughly débride all necrotic tissue, and irrigate copiously with sterile saline.
Place a strip of packing strip gauze into the open wound to allow for drainage, and dress the wound appropriately.
TECH FIG 3 • Incision (A) and drainage (B) of a hypothenar abscess.
INCISION AND DRAINAGE OF PARONA’S SPACE INFECTIONS
Approach Parona’s space with a longitudinal incision in the distal forearm just ulnar to the palmaris longus.
If the infection is isolated to Parona’s space, keep the incision proximal to the wrist flexion crease.
If the infection is contiguous with a midpalmar space abscess, the incision is carried across the wrist in Brunner fashion.
POSTOPERATIVE CARE
Intravenous antibiotics, initially given intraoperatively, are continued postoperatively.
The patient may be switched to oral antibiotics once cultures and sensitivities return from the microbiology laboratory and if he or she is responding to IV antibiotic therapy.
Let open wounds heal by secondary intention using wet-todry dressing changes and soaks or whirlpools.
Remove drains after 24 to 48 hours, depending on the condition of the wound and particulars associated with surgery.
Begin early range-of-motion exercises during soaks or whirlpool treatments to minimize digital stiffness.
Treatment of systemic illness is critical.
COMPLICATIONS
Persistent abscess formation if irrigation and débridement is inadequate or the wound is closed tightly and not allowed to drain
Systemic spread of the infection if appropriate treatment is delayed
SUGGESTED READING
Burkhalter WE. Deep space infections. Hand Clin 1989;5:553–559. Hausman MR, Lisser SP. Hand infections. Orthop Clin North Am 1992;23:171–185.
Leddy JP. Infections of the upper extremity. J Hand Surg Am 1986;11:294–297.
Siegel DB, Gelberman RH. Infections of the hand. Orthop Clin North Am 1988;19:779–789.