Temporal artery biopsy technique

INTRODUCTION — Temporal artery biopsy is the primary modality for establishing a diagnosis of giant cell (temporal) arteritis. Giant cell arteritis is a chronic vasculitis affecting medium and large diameter arteries, predominantly in older individuals [1,2]. The aortic arch vessels and branches, and particularly branches of the external carotid artery, are most prominently affected [3]. The clinical manifestations result from inflammation of the affected arteries or from their gradual occlusion leading to signs of arterial ischemia [4,5].

The technical aspects of arterial biopsy by which to confirm a diagnosis of giant cell arteritis are reviewed here. The pathogenesis, clinical manifestations, diagnostic evaluation, and treatment of giant cell arteritis, are reviewed elsewhere. (See "Pathogenesis of giant cell arteritis" and "Clinical manifestations of giant cell arteritis" and "Diagnosis of giant cell arteritis" and "Treatment of giant cell arteritis".)

INDICATIONS FOR BIOPSY — Temporal artery biopsy, which identifies the characteristic histopathology, remains the primary modality to diagnose giant cell (temporal) arteritis [6,7]. Other modalities used in the diagnosis of giant cell arteritis are discussed in detail elsewhere. (See "Diagnosis of giant cell arteritis".)

The operating surgeon should be aware that the clinical manifestations of giant cell arteritis may overlap with those of polymyalgia rheumatica and both disease processes occur in similar patient populations [3]. If there is any question regarding the need for biopsy, the operating surgeon should consult the referring physician. The clinical manifestations of giant cell (temporal) arteritis are reviewed elsewhere. (See "Clinical manifestations of giant cell arteritis".)

Temporal artery biopsy is generally a straightforward procedure typically performed using local anesthetic with few complications. As such, there are no absolute contraindications.

GLUCOCORTICOID THERAPY AND TIMING OF BIOPSY — Temporal artery biopsy should be performed as soon as feasible after referral for biopsy [8,9]. However, scheduling of the biopsy should not interfere with initiation of glucocorticoid therapy given the concern for catastrophic vision loss. Histopathologic evidence is evident for at least one month after glucocorticoid therapy has been initiated. Additional information on the effects of glucocorticoid therapy on biopsy results can be found elsewhere. (See "Diagnosis of giant cell arteritis", section on 'Diagnostic accuracy'.)

ANATOMY — Knowledge of the course of the external carotid artery and its branches (superficial temporal artery, facial artery, occipital artery) and anatomic relationships to other structures is important for performing a safe arterial biopsy.

Superficial temporal artery — The superficial temporal artery is a branch of the external carotid artery (ECA) (figure 1). The ECA has multiple branches that supply the face and scalp, including (caudal to cranial) the superior thyroid, lingual, facial, ascending pharyngeal, occipital, posterior auricular, maxillary, and superficial temporal arteries.

The superficial temporal artery arises posterior to the ramus of the mandible within the parotid gland and ascends anterior to the ear after giving off the transverse facial artery, then it courses superiorly over the zygoma, dividing into frontal and parietal branches (figure 2). As it courses over the zygomatic process, it pierces and ascends within the superficial temporal fascia. In this region, there is some overlap between the course of the frontal branch of the superficial temporal artery and temporal branch of the facial nerve, such that dissection should not be carried below the superficial temporal fascia to avoid nerve injury [10]. Immediately beneath the superficial temporal fascia is a loosely adherent subdermal fatty layer [11]. The superficial temporal vein rarely accompanies the artery and tends to be located above the superficial temporal fascia (figure 3). The superficial temporal artery is accompanied by the auriculotemporal nerve, a branch of the mandibular nerve, on rare occasions.

Other cranial arteries — The facial artery provides the major arterial supply to the superficial face. It is a branch of the external carotid artery and courses along the inferior margin of the mandible (figure 2). The facial nerve accompanies the artery. The facial artery gives off multiple branches, including the inferior labial, superior labial, and lateral nasal arteries, terminating as the angular artery.

The occipital artery branches from the external carotid artery at the angle of the mandible. It passes medial to the posterior belly of the digastric muscle and mastoid process accompanied closely by the occipital nerve. The occipital nerve enters the subcuticular tissue below the external protuberance of the occiput and shortly thereafter crosses the occipital artery [12-14].

PATIENT PREPARATION

Diet — Because the majority of temporal artery biopsies can be performed using local anesthetic, the patient can remain on a clear liquid diet. In the rare event that sedation or general anesthesia is needed, any dietary restriction is dictated by the facility's anesthesia protocol. (See 'Anesthesia' below and "Preoperative fasting in adults".)

Medications — Under most circumstances, the patient should be instructed to continue their current medications, particularly antihypertensive medications. Although the risk of bleeding is slightly increased in patients taking anticoagulant or antiplatelet medications, the time needed to discontinue, reverse, or bridge these medications and the risk of adverse events due to their cessation far outweigh the small risk of bleeding associated with the biopsy procedure. The use of local anesthetic with epinephrine reduces the potential for small vessel oozing. If bleeding does occur during the biopsy procedure, it can be controlled with direct pressure, sutures, electrocautery, or topical hemostatic agents.

Antibiotic prophylaxis — Temporal artery biopsy is a clean, superficial, dermatologic procedure with a low incidence of surgical site infection [15]. As such, antibiotic prophylaxis is generally not necessary. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Antimicrobial prophylaxis'.)

BIOPSY PROCEDURE — Temporal artery biopsy involves removal of a segment (at least 1 to 2 cm of in vivo length) of the superficial temporal artery. Unlike other types of biopsies, in which a small sample of tissue is taken relative to the size of the organ (eg, liver biopsy), the temporal artery is excised in total with its transected proximal and distal ends ligated. Of the arteries potentially affected by giant cell arteritis, the temporal artery is the most easily accessible, and excising the vessel has minimal sequelae [16].

Temporal artery biopsy is most typically performed in an outpatient setting (ambulatory surgery or office based), usually in a minor procedure suite. The physician performing the surgery may be an ophthalmologist, neurosurgeon, general surgeon, vascular surgeon, or other surgical specialist.

Informed consent is obtained, and the surgeon should clearly explain the reason for the biopsy, including the potential complications of the procedure. (See 'Complications' below.)

The possibility that a negative biopsy may be obtained, and its implications, should also be explained. Repeat biopsy of the opposite side may be needed if initial unilateral biopsy was chosen. (See 'Side and site selection' below.)

Side and site selection — The superficial temporal artery is the most common artery sampled to establish a diagnosis of giant cell (temporal) arteritis. Biopsy of alternative arterial sites may be needed if the diagnosis remains in question in spite of negative temporal artery biopsies or there is lack of a temporal artery to biopsy. (See 'Alternative biopsy sites' below.)

The superficial temporal arteries are palpated bilaterally to assess for patency and clinical signs of arteritis. A pulse is usually easily detected at the superior margin of the tragus of the ear, but it may be difficult to appreciate due to vessel thickening, or the vessel may be thrombosed. Use of a handheld Doppler is helpful in locating the artery. Some have speculated that using duplex ultrasound to direct biopsy segment may increase the sensitivity of biopsy [17]. Others argue that palpation of abnormal areas of the temporal artery correlates with changes identified on ultrasound (ie, halo sign) and that ultrasound guidance is unnecessary [18]. In a trial that randomly assigned 112 patients to duplex-guided temporal artery biopsy compared with standard techniques, there were no differences in the frequencies of positive biopsy results [19]. However, duplex may be helpful for localizing small or deep temporal arteries. In the trial, failure to harvest an artery occurred more frequently in the standard compared with duplex-guided group.

After identification of the temporal artery, it is marked with an indelible surgical marker with crosshatches where it is abnormal (nodular, tender). Although biopsy of a patent vessel may be preferred, histopathologic changes associated with giant cell arteritis can be identified in a thrombosed artery [20]. Thus, if a patent temporal artery is not found, biopsy of a thrombosed artery may be appropriate.

Physician and patient preference play a role in determining which side, right or left, should be biopsied. Some clinicians prefer unilateral biopsy in all patients followed by biopsy of the contralateral temporal artery if the initial biopsy is negative. Others prefer bilateral temporal artery biopsy on all patients. There are no high-quality data to support one approach over the other. (See "Diagnosis of giant cell arteritis", section on 'Temporal artery biopsy'.)

When presented with a patient for whom temporal artery biopsy is requested, and for whom a side has not been clearly requested, or for whom the stated side for biopsy does not seem consistent with the clinical situation, we use the following approach [21-23]:

●For those with clearly lateralizing symptoms (unilateral headache, unilateral visual disturbance) or signs (eg, unilateral inflamed and/or tender temporal artery), we perform unilateral temporal artery biopsy.

●For those without lateralizing clinical features, we perform bilateral temporal artery biopsies rather than a "blind" unilateral biopsy given the low morbidity of the procedure, the gravity of the diagnosis, and also practical considerations (eg, patient's ability/desire to return for repeat procedure).

In a retrospective review of 1113 patients, temporal artery biopsy was more likely to be positive in patients with jaw claudication plus new headache, scalp tenderness, or decreased vision [21]. In another review of patients selected for unilateral biopsy, a positive biopsy was significantly more likely in patients with visual symptoms (odds ratio [OR] 4.9, 95% CI 1.28-18.70), or an abnormal temporal artery on physical examination (OR 3.2, 95% CI 1.3-7.71) [22].

A negative history or physical examination is more likely if glucocorticoid therapy has been initiated [21]. For these patients, the history and physical findings prior to treatment may help guide site selection if unilateral biopsy is chosen. Consultation with the patient's primary provider or rheumatologist may be helpful. (See "Diagnosis of giant cell arteritis", section on 'Diagnostic accuracy'.)

Materials and equipment — Prior to performing the biopsy, all the necessary medications, instruments, and other equipment should be collected in advance (table 1). Electrocautery using an electrosurgical unit is not usually needed. If bleeding is encountered, a handheld battery-powered electrocautery pen usually suffices. Overhead surgical lighting (permanent or portable) is essential. If bilateral temporal artery sites have been prepared, it is reasonable to use the same set of sterile instruments for both sides.

Patient positioning and skin preparation — The patient should remove all jewelry, including any necklaces or earrings, and should disrobe above the waist. For women, the brassiere should also be removed to eliminate the potential for soilage. The patient is then positioned supine on a standard procedure table with the head placed on a pillow.

For temporal artery biopsy, the patient's head is positioned facing away from the selected temporal artery site to anteriorly position the temporal artery. We prefer to prepare both temporal regions, in anticipation of the need to perform bilateral biopsies. Shaving a small area of hair from the temporal region is usually required to obtain sufficient exposure, and the patient's skin is prepared and drapes placed. Tenting the drapes so the patient's face is not completely covered is better tolerated by the patient. Specific skin preparation agents to prevent surgical site infection are discussed elsewhere. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Antimicrobial prophylaxis'.)

Anesthesia — Arterial biopsy is usually performed using only local anesthesia. Topical lidocaine cream can be applied to the skin for several minutes prior to skin preparation to decrease pain at the lidocaine infiltration site. If the patient is allergic to local anesthetics, total intravenous anesthesia is an alternative, typically administered by an anesthesiologist in an outpatient, ambulatory surgery setting. (See "Overview of anesthesia".)

For temporal artery biopsy, local anesthetic is injected into the skin and subcutaneous tissues over the planned arterial site after the region has been prepared and draped. If bilateral biopsies are performed, local anesthetic is administered just prior to the contralateral incision. We prefer to use a 1:1 mixture of 1% lidocaine with epinephrine (1:200,000) and 0.5% bupivacaine with epinephrine (1:200,000) to provide a rapid onset of analgesia (within four to five minutes) and prolonged pain relief up to three hours.

Biopsy technique — Variability in the technique of temporal artery biopsy, particularly in the amount of temporal artery harvested, may contribute to the variable rates of positive biopsy results that are reported in retrospective reviews. Key points in performing temporal artery biopsy to improve yield and minimize complications include obtaining an appropriate length of vessel (at least 1 to 2 cm in vivo to account for elastic recoil), including visibly abnormal or clinically affected (eg, tender) areas of the vessel, and avoiding nerves.

The incision is generally made overlying the superficial temporal artery at the previously chosen side and site. (See 'Side and site selection' above.)

The incision should be large enough to easily see at least 3 cm of the vessel, and although a horizontal or vertical incision can be made, a vertical incision (parallel to the vessel) facilitates the harvest of a longer segment of the artery. The dissection is carried through the subcutaneous fat parallel to the vessel with care not to injure the vessel; a self-retaining retractor can be placed (figure 4). As the incision is carried through the hairline, disrupting the hair follicles can be minimized by following the direction of the hair shafts to reduce the risk of incisional alopecia. Division of the overlying temporoparietal fascia exposes the superficial temporal artery. At least 3 cm of the artery should be exposed to achieve at least a 1 to 2 cm in vivo temporal artery specimen. The rationale for this length of artery is discussed below. (See 'Specimen length' below.)

The artery is ligated proximally and distally, or small hemostats are used to clamp the artery proximally and distally; the intervening segment of vessel is removed with tenotomy scissors. The arterial stumps are singly or doubly ligated with nonabsorbable suture (eg, silk) (figure 4). Once hemostasis is obtained (pressure, electrocautery, topical agent), the wound is irrigated and closed with subcuticular sutures. We prefer to use 4-0, braided, absorbable suture in the subcutaneous tissue and 5-0 absorbable, monofilament suture in the skin. Adhesive skin strips and a nonadherent, absorbable dressing (eg, Telfa) are placed and covered with a transparent self-adhesive film dressing (eg, Tegaderm). Another option for wound coverage is topical skin adhesive, which can be applied after the skin closure.

Specimen length — Sufficient specimen length is important for an accurate diagnosis due to the segmental nature of the disease process [24]. Unfortunately, supporting data for the various opinions about optimal biopsy length are lacking. The greater the length of artery that can be taken, the greater the likelihood of a positive result [22,25-30]. However, based upon the larger and later studies [28,31,32], a length shorter than is traditionally obtained may be sufficient and may reduce the incidence of complications. It is important to remember that some shrinkage with fixation will occur. One pathology study noted an average of 2.4 mm shrinkage in the length of the biopsy with fixation [28,33]. On average, approximately 10 percent shrinkage can be expected [34]. Given the need to account for shrinkage, we suggest the in vivo specimen length should be at least 1 to 2 cm. If the artery appears normal, a longer segment of the temporal artery should be obtained, provided doing so will not risk additional complications [22,35]. (See 'Complications' below.)

A ruler can be used to measure and document the length of artery, in vivo, prior to its removal. To achieve an adequate length of artery, the dissection may need to be extended superior to the bifurcation of the superficial temporal artery following the course of the frontal or parietal branch. Although the frontal branch is easier to expose, branch facial nerve injury may lead to eyebrow droop [36-38]. This complication can be avoided by extending the biopsy toward the parietal branch instead when additional length is needed.

Studies providing information regarding optimal specimen length include the following:

●In a retrospective review of 1190 biopsies from 1163 patients, a positive compared with negative pathologic diagnosis was associated with increased age (75.3 versus 71.3 years), erythrocyte sedimentation rate (ESR; 57 versus 36 mm/h), C-reactive protein (CRP; 51.6 versus 12.1 mg/L), and biopsy length (1.6 versus 1.2 cm) [39]. In a multivariate analysis adjusted for age, ESR, and CRP, biopsy length remained a significant predictor. Accounting for postfixation shrinkage, the authors suggested a 1.5 to 2.0 cm biopsy specimen prefixation length as optimal, with greater lengths unlikely to provide significant additional diagnostic yield to justify risks. In this review, the mean patient age was 72 years, and 68.7 percent of patients were women. Positive biopsies were obtained in 18.7 percent of patients.

●In a retrospective review of 966 temporal artery biopsies obtained over five years at six hospitals, biopsies with a postfixation specimen length of >0.7 cm had a significantly higher rate of positive results compared with shorter lengths (24.8 versus 12.9 percent) [28].

●In an earlier review of 200 specimens, the average length that gave positive results was significantly longer than the length that gave normal results (1.1 versus 0.86 cm) [31].

●A review of 47 biopsies found average lengths for positive and negative biopsies were 1.84 and 1.29 cm, respectively [32].

●In a series of 134 biopsies obtained over a 15-year period, positive biopsy samples had a mean length that was shorter compared with negative biopsy samples [40]. In this study, biopsy samples were relatively long, (unilateral biopsy: mean length 3.5 cm [range 0.5 to 12.5 cm]; bilateral biopsy: mean length 6.7 cm [range 1.5 to 17.5 cm]).

Alternative biopsy sites — Although giant cell arteritis is often called "temporal" arteritis, the disease process is not limited to the temporal artery [41-43]. Other accessible vessels such as the facial or occipital arteries may be affected, and, on occasion, these may be used as alternative biopsy sites [44,45].

If the temporal arteries are not symptomatic and have no abnormalities on examination but the facial or occipital arteries are symptomatic and abnormal on physical examination, then facial or occipital artery biopsy can be performed in a manner that is similar to temporal artery biopsy. Biopsy of these vessels may also be considered if bilateral temporal artery biopsy is negative and the diagnosis remains in question.

Biopsy of these vessels can be performed; however, each is accompanied by its respective nerves, and the risk of nerve injury may outweigh the usefulness of obtaining a specimen from these sites. For the occipital artery, some suggest that the biopsy site should be between 1 and 3 cm above (cranially) and 4 to 5 cm lateral to the external occipital protuberance to avoid occipital nerve injury [14]. (See 'Other cranial arteries' above and 'Nerve injury' below.)

Specimen handling — Once the arterial segment has been removed, it should be immediately placed into a clearly labelled specimen jar containing formalin for permanent section. In medical centers with appropriate experience, a portion of the specimen can be sent for frozen section to secure an immediate diagnosis. However, fixed, permanent sections should be obtained in all instances. The patient's primary physician or rheumatologist should be included in the report for notification of the results. The histologic findings of giant cell arteritis are described elsewhere. (See "Diagnosis of giant cell arteritis", section on 'Interpretation of histopathologic findings'.)

FOLLOW-UP INSTRUCTIONS AND CARE — Once the temporal artery biopsy procedure is completed and the dressings have been placed, the patient can return home as soon as they meet discharge criteria. For most patients, this is fairly immediate. The patient is instructed to maintain the dressing over the biopsy site(s) for 24 hours, after which any previously placed outer transparent film dressing can be removed. If adhesive strips were used on the skin, they should remain in place for several days. The patient is instructed to avoid the region when washing their hair.

The patient should be informed that the sutures placed beneath the skin will be absorbed and thus do not require removal. The incision(s) may become itchy, but the patient should avoid scratching the area. The patient should call the surgeon if there are any wound-related problems (bleeding, drainage) or other questions. Under most circumstances, the patient can expect to be notified of the pathology results within two to three days.

NEED FOR REPEAT BIOPSY — If the biopsy is negative, the patient's primary physician or rheumatologist may request additional biopsy depending upon the initial presenting symptoms and response to glucocorticoid therapy. For patients with negative bilateral temporal artery biopsy, biopsy of alternative sites may be needed to establish a histologic diagnosis. (See 'Alternative biopsy sites' above.)

COMPLICATIONS — Complications of temporal artery biopsy are uncommon but may include bleeding (arterial or venous), surgical site infection, and nerve injury involving the auriculotemporal nerve, or branches of the facial nerve.

Bleeding — The most common sequelae of temporal artery biopsy is minor oozing from the wound; however, sudden, more significant bleeding can occur if a ligature dislodges from the cut end of the proximal temporal artery. The use of double ligation or, for larger vessels, suture ligation, rather than simple ligation, may help avert this problem. Bleeding can usually be controlled with direct pressure, but, under rare circumstances, re-exploration of the wound may be needed.

Nerve injury — The potential for facial nerve injury is increased when temporal artery biopsy is carried over the frontal branch of the superficial temporal artery [10,36,37,46]. Injury to the facial nerve and complications such as eyebrow droop can be avoided by extending the biopsy towards the parietal branch if additional length is needed [37,38]. (See 'Superficial temporal artery' above and 'Specimen length' above.)

The occipital nerve is easily injured below the occipital protuberance, and injury can lead to upper neck or posterior cranial pain, or pain behind the eyes. Thus, occipital artery biopsy should be performed superior to the occipital protuberance. (See 'Alternative biopsy sites' above and 'Other cranial arteries' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Giant cell arteritis and polymyalgia rheumatica".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Beyond the Basics topics (see "Patient education: Vasculitis (Beyond the Basics)" and "Patient education: Polymyalgia rheumatica and giant cell arteritis (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Giant cell arteritis is a chronic vasculitis affecting medium and large arteries, predominantly in older individuals. The branches of the aortic arch are the most prominently affected. The clinical manifestations result from inflammation of the affected arteries or from their gradual occlusion leading to signs of arterial ischemia. (See 'Introduction' above.)

●Temporal artery biopsy remains the primary diagnostic modality to establish a diagnosis of giant cell arteritis. Temporal artery biopsy involves the removal of a segment of the superficial temporal artery for histologic examination. Although giant cell arteritis is often called "temporal" arteritis, the disease process is not limited to the temporal artery. Other accessible vessels such as the facial or occipital arteries may be affected, and on occasion, these may be used as alternative biopsy sites. (See 'Indications for biopsy' above and 'Alternative biopsy sites' above.)

●Temporal artery biopsy is typically performed in an outpatient setting using only local anesthesia. Fasting is not required, and the patient can continue their normal medications. Although the risk of bleeding is slightly increased in patients taking anticoagulant or antiplatelet medications, the time needed to discontinue, reverse, or bridge these medications, and the risk of adverse events due to their cessation, far outweigh the small risk of bleeding associated with the biopsy procedure. Antibiotic prophylaxis is generally not necessary for this clean procedure. (See 'Patient preparation' above.)

●Some clinicians prefer unilateral biopsy in all patients followed by biopsy of the contralateral temporal artery if the initial biopsy is negative. Others prefer bilateral temporal artery biopsy on all patients. There are no high-quality data to support one approach over the other. Physician and patient preference also play a role in making this decision. (See 'Side and site selection' above.)

Our approach, in the absence of a clearly defined side (as specified by the patient's primary care physician or rheumatologist), is as follows:

•For patients with lateralizing symptoms (unilateral headache, unilateral visual disturbance) or signs (eg, unilateral inflamed and/or tender temporal artery), we suggest unilateral temporal artery biopsy performed on the side of the symptoms/signs (Grade 2C).

•For patients without lateralizing symptoms or signs, we suggest bilateral temporal artery biopsy (Grade 2C).

●A sufficient specimen length is important for an accurate diagnosis due to the segmental nature of the disease process. We suggest a minimum in vivo temporal artery biopsy length of at least 1 to 2 cm (Grade 2C). The greater the length of artery that can be taken, the greater the likelihood of a positive result, particularly if the vessel is normal in appearance. Other key points in performing the biopsy procedure include biopsy of clinically affected areas of the vessel and avoidance of local nerves. (See 'Biopsy technique' above.)

●For patients with a negative biopsy, repeat biopsy may be requested. Biopsy of alternative sites can be performed if a histologic diagnosis is needed. (See 'Need for repeat biopsy' above and 'Alternative biopsy sites' above.)

●Complications of temporal artery biopsy are uncommon; however, bleeding (arterial or venous), surgical site infection, and nerve injury can occur. Incisional alopecia can also occur but can be avoided if the incision is made parallel to the plane of the hair shafts. (See 'Complications' above and 'Biopsy technique' above.)