Updated: 1/7/2019

Hypothenar Hammer Syndrome

Topic
Review Topic
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0
Questions
2
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Evidence
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Cases
1
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Introduction
  • Post-traumatic digital ischemia from thrombosis of ulnar artery at Guyon's canal.
  • Epidemiology
    • incidence 
      • rare
    • demographics
      • male: female ratio is 9:1
      • age bracket is 40s-50s
    • location
      • unilateral, dominant ring finger +/- small finger
      • less commonly, index and middle fingers
      • thumb is spared
    • risk factors
      • occupations using vibrating tools such as carpenters, machinists, mechanics 
      • sports such as baseball catchers, mountain biking, golf, volleyball, karate
  • Pathophysiology
    • mechanism
      • single or repetitive blunt impact on hypothenar eminence leads to ulnar artery thrombosis or aneurysm 
      • hook of hamate functions as an anvil, causing thrombosis
      • distal embolisation leads to ulceration, gangrene
Anatomy
  • Ulnar artery
    • ulnar artery branches into 2 branches as it exits Guyon's canal 
      • deep branch
      • superficial palmar arch in Guyon's canal
    • relation to hook of hamate
      • over distal 2cm, the artery is directly anterior to the hook of the hamate, covered by palmaris brevis, subcutaneous tissue and skin  
Presentation
  • History
    • occupational or sporting risks (see above)
  • Symptoms
    • pain over hypothenar eminence and ring finger
      • may involve small, middle and index fingers
    • cold sensitivity
    • paresthesia
  • Physical exam
    • inspection
      • blanching, mottling, cyanosis, pallor, gangrene
      • tenderness over hypothenar eminence
      • prominent callus (calloused skin over hypothenar eminence)
      • pulsatile mass if aneurysm is present
      • fingertip ulcerations over ulnar digits
      • splinter hemorrhages over ulnar digits
    • provocative tests
      • Allen's test
        • positive if occlusion is present
        • negative if aneurysm is present
Imaging
  • Doppler ultrasound
    • indications
      • first line test 
      • measure digital brachial index
        • <0.7 necessitates reconstruction
  • Angiogram, CT angiogram or MR angiogram  
    • indications
      • mandatory for diagnosis
    • findings
      • tortuous "corkscrew" ulnar artery
      • occlusion or aneurysm at the hook of the hamate  
Differential
  • Raynaud's disease involves the thumb but hypothenar hammer syndrome does not
Treatment
  • Nonoperative
    • lifestyle modifications, symptomatic treatment, and vascular consult
      • indications
        • thrombosis without aneurysm > 2 weeks
        • asymptomatic
        • no threat of digital loss
      • lifestyle modifications
        • smoking cessation
        • avoid recurrent trauma
      • outcomes
        • 80% success
  • Operative
    • endovascular fibrinolysis
      • indications
        • thrombosis without aneurysm < 2 weeks
    • excision of involved segment and reconstruction with or without a vein graft   
      • indications
        • digital brachial index <0.7 
        • thrombosis with aneurysm
        • ischemia in multiple digits
        • failed conservative treatment with recurrent symptoms
    • arterial ligation (Leriche procedure)
      • indications
        • digital brachial index >0.7 
 

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Questions (2)
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(OBQ13.37) A 35-year-old mixed martial arts fighter and recreational cocaine user presents with symptoms concerning for hypothenar hammer syndrome (HHS). Significant ischemia is found on physical exam. Arteriography is shown in Figure A. What is the most appropriate next step in treatment? Review Topic

QID: 4672
FIGURES:
1

Conservative treatment with cocaine abstinence

8%

(416/4917)

2

Conservative treatment with activity modifications and medical management with calcium channel blockers

13%

(629/4917)

3

Therapeutic endovascular fibrinolysis

6%

(283/4917)

4

Excision of involved segment and reconstruction with or without a vein graft

71%

(3501/4917)

5

Medical management with coumadin for 6 months

1%

(46/4917)

L 4

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ARTICLES (6)
CASES (1)
Topic COMMENTS (5)
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