A temporal artery biopsy is performed by a surgeon trained and proficient with the procedure. This is typically an ophthalmologist accompanied by a nurse for intraoperative assistance and post-procedure monitoring.
Appropriate biopsy site selection is critical to confirm the diagnosis of giant cell arteritis. Clinical symptoms such as visual disturbances, headache, or a painful vessel assist the surgeon in selecting laterality for the temporal artery biopsy, even though the physical examination poorly correlates with biopsy results.
After choosing which temporal artery to biopsy, Doppler ultrasound is employed to identify a peripheral segment of the frontal branch of the temporal artery in the anatomic safe zone. This branch is often located just posterior to the anterior hairline, a location that facilitates cosmesis and scar camouflage.
The patient is placed in a reclined position. The surgeon makes two marks: at least a 5-centimeter length of the artery and a 3- to 4-centimeter incision. This length of the artery is necessary due to the potential for segmental manifestations of the underlying disease process.
Technique or Treatment
Trim the hair as necessary and scrub and drape the skin in the normal fashion. Anesthetize the intended area with 5 to 10 mL of lidocaine with epinephrine; extend the area to 1 cm lateral to the artery on either side. Using the No. 15 scalpel blade, incise the dermis directly over the artery such that the thin subcutaneous tissue is barely visible. Separate the edges of the incision using blunt-tipped dissecting scissors and skin hooks; dissect to uncover the superficial temporal fascia. Grasp this fascia with forceps a few millimeters lateral to the artery. Incise the fascia sharply with scissors and enlarge the fascial incision to expose the artery. Palpation of the arterial pulse may facilitate identifying the vessel.
Gently harvest approximately 5 centimeters of the vessel. Use suture or indirect electrocoagulation via forceps to ligate any small branches of the temporal artery prior to transection; this promotes a relatively bloodless surgical field. Ligate the proximal and distal portions of the main vessel using 4-0 or 5-0 polyglactin 910 suture, transect the vessel, and place the specimen in formalin. Apply electrocoagulation to the vessel ends in situ. Ensure that hemostasis is achieved. Approximate the skin edges with 5-0 poliglecaprone subcutaneous sutures, and complete the closure with either a cyanoacrylate skin adhesive or 6-0 gut sutures.
A significant challenge facing the pathologist interpreting the TAB is the potential for false-negative results, which may occur in 5% to 10% of cases. Therefore, the surgeon must perform the TAB employing appropriate biopsy site selection, meticulous tissue handling, and adequate specimen length to maximize diagnostic yield. Unfortunately, despite the correct technique, false-negative results remain common. In some cases, bilateral TAB may increase the yield and decrease the false-negative rates.
The most dreaded complication of TAB is temporary or permanent damage to the temporal branch of the facial nerve. Techniques to reduce the risk of nerve injury include ultrasonographic localization of the artery, placement of incisions directly superficial to the artery to protect the potentially deeper running nerve, and blunt dissection only within or above the superficial temporal fascia. A 2009 study found that 1.25% of TAB specimens contained a portion of the temporal facial nerve, and a 2012 study found that 4% of patients undergoing TAB had frontalis dysfunction with no improvement at 6 months.
Other than common surgical complications such as bleeding, infection, hematoma, and wound dehiscence, possible, albeit rare, complications of TAB include ischemic stroke and scalp or tongue necrosis, which have been reported. Some authors recommend palpating and firmly holding a bounding temporal artery pulse for several minutes before proceeding with TAB or locating a major arterial branch other than that being biopsied via ultrasound to ensure collateral vascular supply and minimize the risk of subsequent stroke.
The gold standard for diagnosing giant cell arteritis is a temporal artery biopsy. Due to a relatively low negative predictive value, however, a negative biopsy result does not definitively rule out the diagnosis. Currently, patients are considered to have the diagnosis of temporal arteritis if three of the following five clinical features are present:
Reference Link: Detailed Article on Temporal Artery Biopsy. Patel BCK
Dr. BCK Patel MD, FRCS