Since first introduced by Wang in 1985,1 the larger-gauge flexible needle for transbronchial needle aspiration (TBNA) has enabled a cord of tissue to be obtained for histologic examination. However, we often find that the yield from this method is sufficient for cytologic but not histologic examination. We describe our experience with a mediastinal sampling technique using a miniforceps as an adjunct to TBNA to improve the yield for histologic testing.
MATERIALS AND METHODS
A total of 22 consecutive patients with enlarged subcarinal nodes, 10 mm or greater in short-axis diameter on chest computed tomography, were included in this prospective study conducted at Nagoya National Hospital from July 2001 to September 2002. Informed consent was obtained before bronchoscopy in all patients. TBNA and miniforceps biopsy (MFB) for obtaining specimens from subcarinal nodes always preceded other bronchoscopic procedures such as brushing, biopsy, or washing of the primary lesion. All TBNA and MFB procedures were performed by the same practitioner (M.O.) who has extensive experience in TBNA procedures.
For TBNA, we used a 19-gauge histology transbronchial needle (1.1-mm external diameter, MW-319; Bard Corp., Boston, MA). The site chosen for puncture was the center of the main carina or right mainstem bronchus within 1 cm of the main carina. TBNA was carried out by a technique similar to that previously described by Wang,2 except that the specimen collected at the lumen of the TBNA needle was first blown onto a glass slide by air in a dry syringe. The visible tissue fragment on the slide was then collected and transferred into formalin for histologic examination, and the remaining specimen on the slide was immediately smeared and placed into a jar of 95% alcohol for cytologic examination. Multiple punctures were made at the same site until at least 1 or more satisfactory specimens were obtained.
For the forceps biopsy, a miniforceps with an external diameter of 1.15 mm (FB-56D-1; Olympus, Tokyo, Japan) was used. Because the forceps are soft, they were reinforced by an outer flexible catheter sheath of MW-319, which was cut approximately 70 cm from the tip. The tip of the closed miniforceps was inserted into the catheter sheath and then advanced a few millimeters beyond the distal end of the catheter sheath (Fig. 1). The ensheathed forceps were then inserted into the working channel of the bronchoscope after the puncture site made by a TBNA needle had been visually identified. The forceps were then passed through the channel. Once the tip of the forceps was visualized with bronchoscopy, the forceps were advanced slowly toward the TBNA site. Once they reached the site, the forceps were then pushed forcefully against the bronchial wall and inserted through the puncture site in the bronchial wall (Fig. 2). After fluoroscopically confirming that the forceps had advanced into the extrabronchial region, the jaws were then manipulated so as to open (Fig. 3). If the jaws failed to open completely, the forceps were slightly withdrawn and readvanced several times using their handle for the manipulation. To obtain a specimen, the open jaws were pressed firmly against the lymph nodes, closed to grasp a node, then pulled back from the nodes and withdrawn through the bronchoscope. Because the jaws of the forceps are small, as many passes as necessary were made until 5 biopsy specimens were obtained.
In the first group of 11 consecutive patients (group 1), TBNA was performed before MFB at the same site. In the second group of 11 patients (group 2), MFB was performed before TBNA. First the TBNA needle was used to open the puncture site for MFB. Thus, there was no biopsy done on the initial penetration by the TBNA needle. The external diameter of the 19-gauge TBNA needle was 1.1 mm, slightly smaller than that of the miniforceps at 1.15 mm. Thus, under bronchoscopic control, the needle was first manipulated for shallow penetration of the bronchial wall, then moved vertically and horizontally so as to enlarge the puncture site to allow easier passage of the forceps through the wall. Because the TBNA biopsy procedure was first conducted a number of times in group 1, the puncture site was naturally enlarged enough to facilitate the MFB. It was expected that the passage of the miniforceps through the bronchial wall would be more difficult in patients in group 2 because the bronchial wall puncture site from TBNA would be smaller. Therefore, if difficulty was encountered during the MFB procedure in patients in group 2, the TBNA biopsy was arranged to precede the MFB as in the patients in group 1.
Insertion of the 19-gauge TBNA needle through the bronchial wall was feasible in all 22 patients studied, thereby allowing specimens for cytologic examination to be obtained from all of them. At least 1 histologic specimen was obtained by TBNA in 19 of these 22 patients (10 in group 1, 9 in group 2). In the remaining 3 patients, specimens for histologic examination could not be prepared because the yield was either too small or fragmented.
In 18 of the 22 patients, at least 1 specimen for histologic analysis was obtained by MFB (9 patients in each group). However, because the miniforceps could not be passed through the bronchial wall before TBNA biopsy in 3 patients in group 2, the MFB was carried out after the TBNA procedures for these patients. In 3 of the 4 patients with whom MFB was impossible, a miniforceps could not be introduced into the TBNA puncture, and the retrieved tissues were lost because of the small sizes and fragmentation in 1 patient.
A specific diagnosis was made in 12 patients (8 malignancies, 3 sarcoidosis, 1 tuberculosis) (Table 1). Cytologic examinations of the TBNA were positive in all 8 patients with malignancies. In group 1, TBNA and MFB established the histologic diagnosis in 4 and 3 patients, respectively, whereas in group 2, they provided the histologic diagnosis in 5 and 7 patients, respectively. Three of 7 patients diagnosed by MFB in group 2 underwent TBNA biopsy first. In total, diagnostic tissue was obtained by MFB in 3 patients with negative histologic results of TBNA (2 sarcoidosis, 1 small cell carcinoma).
One patient experienced a subclinical mild pneumomediastinum, which healed spontaneously.
Training and experience are required to achieve a good diagnostic sampling yield using TBNA.3,4 Technically, TBNA for histologic specimens is much more difficult than for cytologic specimens and, therefore, an adequate amount of tissue for histologic examination cannot always be obtained even by experienced hands. In the early studies of the procedure using an 18-gauge TBNA needle, the success rate for histologic specimen retrieval was reportedly 50% to 86%.1,5,6 The development of a finer 19-gauge histology needle with design modifications has permitted easier penetration of the tracheobronchial wall and assured higher sampling yield.7,8 However, the yield is still not always sufficient for a diagnosis. Specimen sampling from fragile tissue is particularly difficult, because such a specimen is fragmented and easily lost when it is sucked back and packed into the needle lumen. Forceps would provide a more certain yield because of their characteristic “grasp.”
Oho and Amemiya described that they successfully obtained histologic specimens from subcarinal nodes using a high-frequency cutter and normal-sized forceps.9 The carinal wall was punctured by a high-frequency cutter, then the forceps was introduced into the puncture site to obtain specimens. We modified their techniques using finer instruments.
We studied 2 groups of patients. In patients in group 1, MFB was performed after TBNA biopsy to determine whether the MFB could play an adjunctive role to TBNA. In patients in group 2, MFB was done before TBNA biopsy to investigate the use of MFB with minimal effects of TBNA. In both groups, the 2 procedures tended to yield diagnostic specimens in the same cases if enough tissue for histologic analysis was obtained. However, as expected, the MFB procedure in patients in group 2 was much more difficult than in patients in group 1. Three of the patients in group 2 had to undergo MFB after TBNA biopsy as in group 1. The major technical difficulties of the procedure are the passage of the miniforceps through the TBNA puncture site and opening the jaws in the extrabronchial space. Because the external diameter of the miniforceps is slightly larger than that of 19-gauge TBNA needle, careful enlargement of the TBNA puncture site is essential for its smooth passage. In patients in group 2, the TBNA puncture site in the bronchial wall is smaller and the peribronchial tissue is denser. On the other hand, in patients in group 1, the TBNA puncture and extrabronchial space have been repeatedly enlarged by the prior TBNA procedure. The sequential performance of TBNA biopsy followed by MFB seems reasonable based on our experience. Surprisingly, it was not difficult to advance the miniforceps to the identical site punctured by the TBNA needle because multiple TBNAs had been performed at the same site. However, unexpected factors such as severe coughing, tracheobronchial collapse, or bleeding occasionally made it difficult.
In our series, the diagnostic tissue was obtained by MFB and not TBNA in 3 patients (2 sarcoidosis, 1 small cell carcinoma). In the 3 patients in whom TBNA was unsuccessful, specimens for histologic examination could not be prepared as a result of fragmentation in 2 patients and inadequate specimens containing fibrotic tissue and clots in 1 patient. Although the TBNA cytologic specimen also made possible the diagnosis in the patient with small cell carcinoma, the remaining 2 patients with sarcoidosis were diagnosed solely by MFB. In evaluating the subcarinal nodes, the addition of MFB to the TBNA procedure promises to increase the sampling yield of diagnostic tissue. It will be especially useful in a patient with suspected benign diseases for which cytologic examination might not be as informative.
There was 1 complication that related to MFB or TBNA in our series, a subclinical pneumomediastinum, which healed spontaneously. Oho and Amemiya described that the 1.8-mm forceps biopsy of subcarinal nodes was safe.9 Potentially, our techniques using smaller forceps would be much safer.
Because the sample obtained by MFB is small, multiple passes are required to obtain adequate specimens. Consequently, the bronchoscopy time could be prolonged. Although MFB offers a helpful adjunct to TBNA, the procedure should be performed only in selected cases. Indications for MFB are cases in which satisfactory visible specimens cannot be obtained despite multiple trials with TBNA.
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