44.1 Description

Temporal artery biopsy (TAB) is a simple procedure to obtain an artery specimen to diagnose giant cell arteritis (GCA). This systemic disease is an inflammatory vasculopathy causing segmental necrotizing reaction in the vessel wall of medium-to-large size arteries characterized by a predominance of mononuclear cell infiltrate or a granulomatous process with multinucleated giant cells. ¹ GCA is known to have skip lesions, areas that are uninflamed between other areas of inflammation. Therefore, a negative TAB result cannot be used to rule out GCA. While there are criteria for clinical diagnosis of GCA, the definitive diagnosis is based on a positive histopathologic specimen.

44.2 Key Principles

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  Intimate knowledge of the temple anatomy is crucial for successful surgery without complication. In most cases, the parietal branch can be biopsied safely. Although its presence within the hairline (n) may interfere with visualization of the surgical site, it generally heals well with low risk of alopecia, creating a favorable invisible biopsy site.

  
  
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  Meticulous preoperative mapping of the course of the artery is critical.

  
  
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  A sufficient length of artery should be biopsied for the highest likelihood of a representative sample. In general, a 3-cm length is sufficient.

  
  
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  Due to the presence of skip lesions, the artery to be biopsied should be made based on symptoms (indicating laterality) and clinical findings (painful, enlarged, tender, pulseless arteries). If clinical suspicion for GCA is high, a negative biopsy should be followed by an additional biopsy.

44.3 Anatomy

The superficial temporal artery is one of the terminal branches of the external carotid artery and supplies the face and scalp. It begins at the level of the parotid gland and passes over the zygomatic arch. About 3 to 5 cm above this bone, it divides into the frontal and parietal branches. It runs posterior to the superficial temporal vein and anterior to the auriculotemporal nerve. Importantly, it lies within the superficial temporal fascia along with the temporal branch of the facial nerve; so, care should be taken not to injure these structures.

44.4 Expectations

This procedure can be performed in the office setting in less than 30 minutes. Local anesthesia alone is generally sufficient for patient comfort. Although the risk of postoperative hemorrhage and facial nerve damage exists, it can be minimized by proper site selection (avoiding the “danger zone”), blunt dissection in the area of the facial nerve, and clear exposure of the surgical site.

44.5 Indications

Biopsy is warranted based on clinical suspicion. GCA can cause a myriad of ophthalmic findings including arteritic ischemic optic neuropathy, retinal artery occlusion, choroidal ischemia, cotton-wool spots, and cranial nerve palsies. The American College of Rheumatology established diagnostic criteria for GCA. ¹

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   Age ≥50 years at disease onset.

   
   
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   New onset of localized headache.

   
   
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   Temporal artery tenderness or decreased temporal artery pulse.

   
   
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   Elevated erythrocyte sedimentation rate ≥50 mm/hour by Westergren method.

   
   
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   Positive TAB.

The presence of three or more of these criterias has been reported to have a sensitivity of 93.5% and specificity of 91.2%. The presence of jaw claudication has the highest predictive value for a positive TAB. ²

44.6 Contraindications

There are no absolute contraindications to biopsy. Some authors recommend caution in patients using steroids for greater than 2 weeks, as the interpretation of the histopathologic result may be confounded. Positive results still can be found even after 6 weeks of using steroids, but the percentage of these results decreases. ³ Current use of blood thinners can increase the risk of perioperative bleeding, ⁴ although a delay in biopsy is not recommended due to the devastating consequences of a missed or delayed diagnosis. Bleeding can be stopped by ligating bleeding vessels or applying pressure to the area.

44.7 Preoperative Preparation

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  Risk, benefits, and alternative are explained to the patient, and informed consent is obtained.

  
  
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  Start by palpating both superficial temporal arteries looking for area of tenderness and nodularity; the side that has ocular manifestations or symptoms is recommended for biopsy.

  
  
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  Place the patient in supine position with the head looking away from the affected side.

  
  
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  Then, using a marking pen, trace the artery and confirm the course and area with the Doppler ultrasound. Biopsy of the parietal branch is recommended. Length should be 3 cm or more (Fig. 44‑1).

  
  
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  Inject local anesthesia (1:1 of 2% lidocaine with 1:100,000 epinephrine mixed with 0.5% bupivacaine) adjacent to the marking to avoid intra-arterial infiltration.

  
  
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  Although always not needed, consider trimming overlying hair with scissors to improve visualization. Shaving the area is generally not needed. Application of ointment or gel lubricant (as used for the Doppler ultrasound) is needed to retain hair away from the surgical field.

  
  
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  Sterile preparation of the surgical field using Betadine 10% solution. Drape the area with sterile towels leaving the face exposed to allow patient to breathe without any problem.