DEFINITION

Deep space infections occur in one of three anatomically defined potential spaces within the hand.

Thenar, midpalmar, and hypothenar spaces Interdigital subfacial web space

Parona space—a potential forearm 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. Other common pathogens include streptococci and coliforms.2

 

 

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.

 

 

 

FIG 1 • Cross-sectional anatomy of the hand demonstrating the deep spaces.

 

 

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.

 

The hypothenar space (see 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.

 

The interdigital subfacial web spaces are three interdigital spaces at the distal end of the palm containing loose subcutaneous fat. These spaces are located near the metacarpophalangeal joints, just proximal to the deep transverse ligaments.

 

Parona 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.

 

Interdigital subfacial web space infections usually result from penetrating injury but may also result from

spread of an adjacent lumbrical canal infection or infected palmar blister.1

 

Parona space infection may result from direct penetrating trauma, in which case the infection may be isolated to Parona space.

 

 

Infection involving Parona space may also result from contiguous spread from a ruptured radial or ulnar bursae (FIG 2). The end result will be involvement of the midpalmar space and a horseshoe abscess (FIG 3).

 

 

P.1155

 

 

 

 

FIG 2 • Radial and ulnar bursae may communicate in the distal volar forearm (Parona space).

 

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.

 

 

 

 

FIG 3 • Drawing representing the clinical appearance of a horseshoe abscess.

 

 

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.

 

In the case of interdigital subfacial web space infection, the patient will present with swelling and tenderness in the dorsum of the hand and maximal tenderness on the palmar aspect of the web space.

 

 

If the infection is severe, the fingers may be abducted on either side of the infected web space.1

 

Infection of Parona space is characterized by swelling in the distal volar forearm and pain with digital flexion.

 

 

Infection involving Parona space may also result from contiguous spread from a ruptured radial or ulnar bursae (see FIG 2).

 

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 intravenous [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

P.1156

 

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 fingers, 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.

 

Drainage of interdigital subfacial infections are performed through either a palmar incision, or through both palmar and dorsal incisions, just proximal to the actual web space.

 

Parona space may be approached through a longitudinal incision just ulnar to the palmaris longus.

 

 

Alternatively, a transflexor carpi radialis approach may be used.

 

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 fingers, 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.

   

   

   

  TECH FIG 1 • A. Thenar incision. B,C. Neurovascular bundle. D. Alternative dorsal incision for drainage of thenar 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.

   

• Incision and Drainage of Midpalmar Space Infections

  P.1157

   

  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.

   

   

   

  TECH FIG 2 • A. Transverse incision for drainage of midpalmar abscess. B. Curved longitudinal incision for drainage of midpalmar abscess. C. Drainage of midpalmar abscess (neurovascular bundle protected by Freer).

   

   

   

  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.

• 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).

   

   

   

  TECH FIG 3 • Incision (A) and drainage (B) of a hypothenar abscess.

   

   

  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.

   

• Incision and Drainage of Interdigital Subfacial Web Space

  P.1158

   

  Approach the interdigital web space with a palmar incision, and excise the palmar fascia lying within the interdigital web space to gain better access for drainage of the infection.1

   

  Alternatively, both a palmar and dorsal incision may be used.

   

   

  Irrigate both the dorsal and palmar extension of the web infection with thoroughly with sterile saline. Transverse incisions or extension of incisions into the transverse web should be avoided, as they may cause web contracture.1

• Incision and Drainage of Parona Space Infections

   

   

  Approach Parona space with a longitudinal incision in the distal forearm just ulnar to the palmaris longus. If the infection is isolated to Parona 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.

   

  PEARLS AND PITFALLS
  		Misdiagnosis

  • Recognize underlying osteomyelitis in long-standing cases.

   

   

   

• Recognize any systemic illness that may hinder resolution of the infection.

 

Presurgical planning

• Always obtain radiographs to evaluate for osteomyelitis or a foreign body.

   

  Technique ▪ When approaching the thenar space, protect the digital nerves to the thumb and index fingers, the princeps pollicis artery, the proper digital arteries, and the recurrent motor branch of the median nerve.

  • In the midpalmar space, protect the superficial palmar arch and the digital nerves and arteries.

  • In the hypothenar space, protect the ulnar nerve and its branches, together with the ulnar artery.

  • Obtain Gram stain and cultures for anaerobes, aerobes, mycobacteria, and fungi.

  • Administer IV antibiotics intraoperatively once cultures have been obtained.

  • May close over Penrose drain if débridement is adequate

  • If there is the possibility of remaining necrotic tissue, the wound should be left open to close by secondary intention.

 

Postoperative care

• Allow open wounds to heal by secondary intention with wet-to-dry dressing changes.

• IV oral antibiotics for 7-14 days

• Infectious disease consultation, if necessary

• Maintain elevation.

• Use of a removable splint will rest soft tissues and improve patient comfort.

• Perform soaks in warm water three times per day.

• Begin early digital range-of-motion exercises.

• Be prepared to repeat irrigation and débridement if there is no clinical improvement after 48 hours.

 

POSTOPERATIVE CARE

 

IV 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-to-dry 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

 

 

REFERENCES

1. Franko OI, Abrams RA. Hand infections. Orthop Clin North Am 2013;44(4):625-634.

    

    

2. Hausman MR, Lisser SP. Hand infections. Orthop Clin North Am 1992;23:171-185.

 

 

SUGGESTED READINGS

Burkhalter WE. Deep space infections. Hand Clin 1989;5:553-559.

 

 

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.