Percutaneous Lung Lesion Biopsy (PLLB)

Article Author:
Michael Young
Article Editor:
Ronald Shapiro
Updated:
10/27/2018 12:31:57 PM
PubMed Link:
Percutaneous Lung Lesion Biopsy (PLLB)

Introduction

Percutaneous lung lesion biopsy (PLLB) is by far the most common indication for percutaneous needle biopsy of the deep tissues of the thorax. Other types of transthoracic biopsies (such as of the mediastinal structures, pleura, or bones) will be discussed in a separate article. 

Percutaneous lung lesion biopsy has one of the highest complication rates among procedures performed by radiologists, with accepted complication rates of around 50% when including injuries that do not require additional intervention. The technical difficulty for achieving tissue diagnosis without concurrent complication has a broad range. Some lesions and patients provide no difficulty, with procedure time less than 30 minutes. Others undergo failed tissue diagnosis even with procedure times extending to more than 90 minutes and/or attempts made on multiple occasions. Decisions regarding patient care for percutaneous lung lesion biopsy are best undertaken by a team of healthcare workers (practitioners from multiple specialties). It may be a better choice for the patient to forego immediate percutaneous lung lesion biopsy after the discovery of a suspicious lung lesion to pursue an endoscopic approach to tissue biopsy and obtain additional imaging to evaluate whether there is a better first option or alternative site for percutaneous biopsy and/or wait for a lesion to grow. The latter option not only may be needed to improve the odds of yielding a specimen but also may provide otherwise unobtainable information about the lesion and its aggressiveness. Disregarding procedure and patient preparation measures often results in an asymptomatic outpatient converting to a pain-filled multi-day or longer inpatient experience. As percutaneous lung lesion biopsy is usually performed without amnestic-degree sedation, the patient usually requires other physician- and nurse-directed action for psychologic and analgesic support. A team approach in which nurses assist with pre-procedure patient education and anesthesia, sometimes support directly by an anesthesiologist, serves the best interest of patients. The aim of this article is to provide specific information on accomplishing these tasks.

Anatomy

In the typical configuration, the lungs are divided into five lobes (three on the right and two on the left) and are surrounded by serous membranes called pleural membranes. The parietal pleura is the inner lining of the thoracic wall, and the visceral pleura is the outer lining of the lungs. Between the membranes is a potential space or cavity called the pleural space that normally contains scant fluid, which allows the visceral pleural to slide along the parietal pleura while still maintaining surface tension (preserving contact) between the membranes. Without this surface tension, the lungs do not remain fully inflated.

The lungs have a dual blood supply by bronchial and pulmonary arteries. The aorta supplies the bronchial arteries, and the right ventricle supplies the pulmonary arteries. The most common configuration of the bronchial arteries is two to the left lung and one to the right. They bifurcate alongside the bronchi and bronchioles. The most common configuration of the pulmonary arteries is one pulmonary trunk with one primary artery per lung and one secondary artery per pulmonary lobe.

Indications

The National Comprehensive Cancer Network (NCCN), the American College of Chest Physicians (ACCP), and the American Society of Clinical Oncology (ASCO) have created guidelines for the diagnosis and treatment of lung cancer. 

The 2018 NCCN guidelines for nonsmall cell lung cancer related to indications for percutaneous lung lesion biopsy advise the following category 2A recommendations:

  • Patients with a strong clinical suspicion of stage 1 or 2 lung cancer (based on risk factors and radiologic appearance) do not require a biopsy before surgery. A biopsy adds time, costs, and procedural risk and may not be needed for treatment decisions. 
  • A preoperative biopsy may be appropriate if a non-lung cancer diagnosis is strongly suspected that can be diagnosed by core biopsy or fine needle aspiration.
  • A preoperative biopsy may be appropriate if an intraoperative diagnosis appears difficult or very risky. If a preoperative tissue diagnosis has not been obtained, then an intraoperative diagnosis (i.e., wedge resection, needle biopsy) is necessary before lobectomy, bilobectomy, or pneumonectomy.
  • Invasive mediastinal imaging is recommended before surgical resection for most patients with clinical stage 1 or 2 lung cancer.
  • The preferred diagnostic strategy for an individual patient depends on the size and location of the tumor, the presence of mediastinal or distant disease, patient characteristics (such as pulmonary pathology and/or other significant comorbidities), and local experience and expertise.
  • The least invasive biopsy with the highest yield is preferred as the first diagnostic study.
  • Anatomic pulmonary resection is preferred for the majority of patients with NSCLC.
  • Patients suspected of having the metastatic disease should have confirmation from one of the metastatic sites if feasible but should have a biopsy of the primary lung lesion or mediastinal lymph nodes if it is technically difficult or very risky to biopsy a metastatic site.
  • Patients with metastatic disease should have the histologic subtype established with adequate tissue for molecular testing (including consideration for re-biopsy or plasma biopsy) to enable the best guidance for chemotherapy options.
  • Decisions about the optimal diagnostic steps for suspected stage 1 to 3 lung cancer should be made by thoracic radiologists, interventional radiologists, interventional pulmonologists, and thoracic surgeons who devote a significant portion of their practice to thoracic oncology.

Although they do not explicitly state it, the most recent ACCP guidelines carry the same general message as the NCCN guidelines that tissue diagnosis by the safest, least invasive means possible is the preferred route of proceeding in all patients with lung lesions. However, the ACCP guidelines suggest that tissue diagnosis is required for chemotherapy/radiation decisions whether the lesions are "obvious" cancers or not. Also, the ACCP guidelines leave open the possibility that treatment can proceed without tissue diagnosis and favor endoscopic biopsy over percutaneous lung lesion biopsy when possible. [1] 

The following ACCP guidelines related to indications for percutaneous lung lesion biopsy are listed below in nearly verbatim language.

  • A joint decision (author's emphasis) among a radiologist, a pulmonologist, and a medical or radiation oncologist is the desirable approach.
  • In patients suspected of having small cell lung cancer (SCLC) based on radiographic and clinical findings, it is recommended that a pathologic diagnosis be confirmed by the least invasive method (sputum cytology, thoracentesis, fine needle aspiration (FNA), or transbronchial aspiration, as dictated by the patient’s presentation (Grade 1C).
  • In patients suspected of having lung cancer who have a solitary (author's emphasis) extrathoracic site suspicious of a metastasis, it is recommended that tissue confirmation of the metastatic site be obtained if an FNA or biopsy of the site is feasible (Grade 1C).
  • In patients suspected of having lung cancer who have lesions in multiple distant sites suspected of metastases but in whom biopsy of a metastatic site would be technically difficult, it is recommended that diagnosis of the primary lung lesion be obtained by the least invasive method (Grade 1C).
  • In patients suspected of having lung cancer who have a peripheral lung nodule, when tissue diagnosis is required due to the uncertainty of diagnosis or poor surgical candidacy, radial EBUS is recommended as an adjunct imaging modality (Grade 1C). If radial EBUS is thought to be unlikely to achieve a diagnosis, then electromagnetic navigation guidance is recommended if the equipment and the expertise are available (Grade 1C). Remark: If electromagnetic navigation is not available, then percutaneous lung lesion biopsy is recommended.
  • If specimens obtained initially are not adequate for histologic and molecular characterization, then pursuing a second biopsy is acceptable given the importance of accurate tumor characterization.
  • In the case of a small (less than 3 cm), solitary, peripheral lung lesion that is suspicious for lung cancer in a patient who appears to have early-stage disease and is a surgical candidate, the diagnostic dilemma generally centers around whether it is necessary to obtain a biopsy specimen to confirm the diagnosis of cancer before surgical resection is carried out. When the lesion is moderate to highly suspicious for lung cancer, surgical excision performed via thoracoscopy is the most definitive method of establishing a diagnosis and determining treatment. In nodules with an indeterminate likelihood of malignancy, sampling via percutaneous lung lesion biopsy or bronchoscopy with or without guidance technology (radial EBUS or electromagnetic navigation) may be considered.

ASCO guidelines affect the management of lung cancer, including on the topics of when molecular tests and which molecular tests are desirable. [2] However, the ASCO guidelines assume that tissue sampling already has been performed and that a tissue diagnosis of cancer has been achieved. 

The Society of Interventional Radiology (SIR) guidelines (discussed below) address some facets of preparation for percutaneous lung lesion biopsy [3] and other aspects of patient care [4] in PLLB but do not provide specific details regarding selection of patients based on lesion characteristics or decisions regarding PLLB vs. other biopsy approaches.

Contraindications

Proceeding to biopsy without taking special precautions is not advisable for a number of pulmonary, sedation, bleeding, and other risks.

Pulmonary function limitations

  • Pulmonary hypertension (as determined on CT or better by Swan-Ganz pressure readings)
  • Positive pressure ventilation may lead to pneumothorax or aggravate a bronchovenous fistula and lead to air embolism
  • Severe bullous emphysema
  • Contralateral pneumonectomy
  • Hydatid cyst
  • Recurrent cough (cough suppressants should be prescribed)

Contraindications to sedation

Determination of periprocedural anesthesia risk is institution dependent. Many hospitals require physicians to assess the patient using the American Society of Anesthesiology (ASA) physical classification system and a Mallampati score. The ASA in 2014 provided greater detail to the classification regarding what constitutes a threat to life (class 4). Symptomatic CHF, sepsis, and myocardial infarction or stroke within 3 months constitute class 4 disease. In general, an uncontrolled or worsening neurologic, respiratory, cardiac, hematologic, or renal situation can qualify as a threat to life. If the patient is ASA class 4 or higher, has unstable risk factors not qualifying as ASA class 4, and/or has any other anesthetic risk factors (such as a "difficult" airway), then some institutions and authors recommend or even require that the patient should have anesthesiology and/or other clinical subspecialist consultation prior even to otherwise "low risk" sedation procedures (Cohn S, ed. Perioperative Medicine. London: Springer-Verlag; 2011). This consultation is to determine whether the risk factor is modifiable/able to be made stable and/or whether extra help should be available during the procedure. It is suboptimal patient care for the radiologist to discover risk factors the day of the procedure and/or to proceed with the biopsy out of the desire to "just get it over with." Patients with difficult airways or low threshold for sequelae of pneumothorax may need to have extra equipment and medications available in the room and/or healthcare personnel made available prior to the procedure to assist with complications. 

Bleeding risks

SIR "standards of practice" recommendations for the cessation of antiplatelet and anticoagulant medications for interventional radiology procedures are categorized based on hemorrhage risks from level 1 to level 3. Percutaneous lung lesion biopsy is classified as a level 2 procedure. For such procedures, the SIR recommends an INR of no more than 1.5 and a platelet count of at least 50,000 cells/microliter. The same guidelines offer specific criteria for the cessation of antiplatelet and anticoagulant medications for level 2 procedures. [3] In the Johns Hopkins Surgical Risk Classification System, which is based primarily on the potential need for blood replacement, percutaneous lung lesion biopsy is considered to be a category 2 procedure (blood loss up to 500 cc) on a scale of 1-4. This is equivalent in risk to laparoscopic cholecystectomy and inguinal hernia repair. Both of these procedures are almost always performed with the aid of an anesthesiologist or certified registered nurse anesthetist present who can help with hemodynamic correction, as well as with airway maintenance and analgesia. A rapid large pneumothorax can cause a degree of chest pain similar to that of a heart attack or aortic dissection. Some lesions can be anticipated to be highly vascular, such as a renal cell carcinoma or melanoma metastasis.

It may be that there is no more reasonable alternative than percutaneous lung lesion biopsy for the next step in a patient's management despite one of the above contraindications. A patient may have poor cardiopulmonary function that would be more likely to lead to death during surgery than during pneumothorax, pulmonary hemorrhage, or other complication from lung biopsy. Or the diagnosis of cancer may be considered too tenuous in the mind of the oncologist that treatment with radiation or chemotherapy would be considered unacceptable without tissue confirmation. In these circumstances, as suggested by the language of the NCCN and ACCP guidelines, it is the responsibility of a team of physicians (primary care, oncology, surgery, pulmonology, etc.) to work together to optimize the patient (e.g. respiratory function, blood pressure, glucose level, coagulation ability), to be ready to assist immediately for percutaneous lung lesion biopsy complications, and to set expectations for the patient.

Other

The reality of percutaneous lung lesion biopsy is that it is often performed on highly mobile targets without the use of real-time imaging guidance. In this setting, a "noncooperative" patient (i.e. a person who cannot lie still or breathe in a controlled fashion for the time needed to perform the biopsy) is a major contraindication to continuing with the procedure. [4] Cooperation is usually a modifiable risk factor (discussed in brief below).

Equipment

Whereas some hospitals have machines that offer continuous CT fluoroscopy that enables the radiologist to watch the needle while advancing it in real time (while radiating his or her own hand), many do not. Although numerous papers have been written advocating the use of a particular type of needle, there remain many variations among radiologists regarding preferred needle size and needle tip shape.

Patient and Room Set Up

All patients should be outfitted with the following (at a minimum):

  • A monitor that can detect blood pressure, cardiac rhythm, oxygen saturation, carbon dioxide waveforms
  • A working intravenous (IV) line

These are necessary because of (1) the rare but occasionally dramatic occurrence of vasovagal episodes that require immediate sedation or delivery of medications without interrupting the procedure or moving the patient, and (2) lung biopsy patients often have serious coexistent medical problems, such as heart disease, that may need emergency medication.

The following should be available:

  • Oxygen
  • Suction equipment
  • Artificial airway and intubation equipment
  • A bag valve mask
  • A resuscitation cart

Other equipment for handling a pneumothorax should include the following:

  • Needle for Seldinger or trocar technique of chest tube introduction
  • Chest tubes with or without a guidewire (4 French is small enough to evacuate air, while 14 French may be needed to evacuate thick blood); a valved tube is useful (one can be created with a stopcock)
  • Heimlich valve for emergent treatment of tension pneumothorax
  • Wall suction
  • Chest drainage system for long-term treatment of pneumothorax/hydrothorax/hemothorax 
  • Connecting stopcocks and tubing

Use of Intravenous Contrast

For lesion localization, a non-enhanced CT alone is usually sufficient because the difference in density between the lung and nodule serves as natural contrast. Occasionally, intravenous contrast agent administration may be required during the procedure, such as to define vascular structures in the anticipated needle path or mediastinal structures.

Preparation

Whereas some lesions are so apical that they do not move with respiration or are so large that they are nearly impossible to miss despite respiratory excursion, many lesions in the 1 to 2 cm range near the diaphragm may take more than 20 minutes of frustrated effort and multiple chest wall punctures attempting to align the biopsy needle with the target lesion prior to entering the lung. CT images for percutaneous lung lesion biopsy are usually only available as axial slices, and the CT machine often only images a 1 cm or so thick slab of tissue. A lesion near the diaphragm may easily move craniocaudal 4 to 5 cm over the course of a standard breath. Just asking the patient to "hold your breath" may not result in success. Even after pinpointing the small lesion within the slab of tissue and then inserting the needle at that level, the patient would need the opportunity to regain his breath so as to hold it again at the time of the needle thrust into the lung. Then the next time the patient holds his breath, he may have moved his torso or diaphragm differently enough that the lesion is no longer visible or that it is visible but a rib, fissure, or diaphragm is now in the line of the site, precluding safe entry. If a new skin entry site is then selected to account for the change, then the patient, not knowing what to do in order to aid the radiologist, may revert back to the first breath hold position on the subsequent breath. This process is made all the more difficult if the patient is sedated. The success or failure of the procedure may devolve into more a matter of chance than of logic or planning while striving for the moment when the needle is properly aligned so as to have a high probability of striking the lesion on the first thrust. Lesions with a higher technical challenge can be addressed in the following ways:

  • Training the patient to breathe in a controlled fashion
  • Positioning the patient to reduce the likelihood of motion and post-procedure air leak
  • Choosing a target with the most desirable features

The Patient as Partner in Promoting a Successful Biopsy

More so than for other types of image-guided biopsies (in which there is neither a biopsy target that moves faster than the imaging machine nor a moderate risk of short-term hospitalization), it may be important prior to the day of the procedure to spend time explaining the usual biopsy experience to the patient and even simulating the experience.

Each patient is slightly different in his or her ability to follow instructions and hold a given position. Patients sent for lung biopsies are often debilitated, dyspneic, arthritic, hard of hearing, and sleep deprived. Holding the same amount of air in the lungs on command is a feat that usually takes practice, even for healthy, highly intelligent persons. There are no known clinical trials that demonstrate that one technique to facilitate consistent breath holds is superior. Nevertheless, emphasizing to the patient his or her own role in contributing to a successful procedure and having the patient practice breath holding and prolonged lying in the planned biopsy position theoretically will improve the chance of a successful outcome. Patients with dependence on 100% oxygen infusion, tracheostomies, phobias (such as to lying partially prone), and/or additional factors that would otherwise prevent successful percutaneous lung lesion biopsy can be trained to turn the moving target into a stationary target. Different methods work better for different patients, and detailed discussion of these methods is beyond the scope of this article.

Patient Position Effects

Chest wall motion is minimized by the prone position. The supine position is associated with moderate chest wall motion, while the lateral decubitus position is associated with the maximum chest wall motion.

True prone positioning is challenging unless there is a specialized head support that enables comfortable breathing face down. A prone oblique position enables the head to be turned to one side and the arms placed below the level of the shoulders. It may be necessary to move the scapula for access. Prone position during biopsy has been associated with lower risk for pneumothorax. [5]

Supine patients are often made more comfortable with a wedge under their knees. It may be necessary to tape a breast out of the way.

Lateral decubitus positions are the least desirable. Patients tend to drift out of this position over time, even if the hips and knees are bent for stability.

Patients are more comfortable with their arms at their sides. All positions should seek to eliminate cervical or other joint strain, pressure on "pressure points," and dyspnea, as these are problems that will result in patient motion increasing procedure duration and risks.

Choice of Target Lesion (in the setting of more than one potential target)

Size is often not the most important factor in selecting a target. A 1 cm pleura-based lesion may be safely directly accessed in the upper lung in a cooperative patient because the upper lung moves little with respiration. However, even a 1 cm lesion would be an undesirable target for direct puncture in the lower lung because of the high likelihood of respiratory misregistration either at the moment of initial pleural puncture or at some point during the course of obtaining subsequent samples.

A large (in the craniocaudal dimension) lesion that either abuts the pleura or is visually distinct from but has adjacent airspace opacification extending to the pleura and which is demonstrated on prior PET-CT to be hypermetabolic is the ideal lesion for percutaneous lung lesion biopsy. The size improves the chance of striking the target. The craniocaudal lesion size is more important than other lesion dimensions (especially if the procedure is performed using a machine that does not have real-time CT fluoroscopy), as that is the dimension that will determine how likely it will be to keep the lesion in the field of view on the imaging monitor during the procedure. A peripheral location in the thorax reduces the chance of striking larger vessels and the chance for needle drift/inadvertent redirection during insertion. The ability to avoid aerated lung on entry diminishes the odds of pneumothorax. A higher metabolic activity increases the chance that viable abnormal tissue will be obtained.

When a lesion large in the craniocaudal dimension is not available as a target, the next most ideal location is one that neither abuts the pleura nor is central (allowing room for needle redirection after a possible inadvertent initial pleural puncture without withdrawing the needle through the pleura, but avoiding proximity to larger central vessels).

The most mobile part of the lung is peridiaphragmatic. The part of the lung most difficult to expand after a pneumothorax is the lung apex. A lesion in the upper region of the lower lobe is preferable to peridiaphragmatic and apical lesions, in that this part of the lung moves little with respiration and because the lower lobe can undergo compression with gravity in the supine position after the procedure to prevent or reduce a pleural air leak.

In a patient with multiple lesions and prior invasive thoracic procedure, the side on which prior surgery was performed should be selected for biopsy. Pleural adherence can increase due to scarring and reduce the chance of a pneumothorax. Puncturing via the thoracotomy scar itself should be avoided, however, because the hard tissue can interfere with needle manipulation.

It cannot be stressed enough that the morphology of the area of concern is a key feature when contemplating lung biopsy. Benign round atelectasis or even "standard non-round atelectasis" can fit of all of the criteria of the optimal "lesion" as described above, including that of being very hypermetabolic on PET, as could a region of parenchymal fibrosis. However, biopsying such abnormalities either with or without an actually associated mass almost never yields clinical benefit. Only true nodules/masses are likely to yield any useful material on pathologic review.

Some scenarios have a probability of failing (with or without the need for emergent surgery) that is more probable than not (i.e., risks outweigh likely benefits).

  • Small immediately subpleural lesions make it very difficult to time needle entry so as to pierce these lesions on the first attempt and to keep the introducer needle in the lesion over the course of obtaining multiple samples (increasing risk for pneumothorax).
  • Small lesions touching the heart are usually unsuitable for biopsy. Cardiac motion on the lesion increases the risk of missing the lesion while placing the patient at high risk for pericardial/myocardial puncture followed by tamponade and death.
  • Nodules along fissures (particularly in the superior portion of the right middle lobe just under the minor dome-shaped fissure) can be difficult to target without puncturing a second lobe (thereby making two additional pleural punctures inadvertently) even with the benefit of an angled CT gantry.
  • Small lesions deep in the costophrenic sulci move a great deal. Inadvertent puncture of the diaphragm (which can be very painful even if there is not associated puncture of an immediately underlying structure such as liver or spleen) is a likely sequela.
  • Ground glass or largely necrotic lesions where the viable cellular yield is likely to be too low from needle sampling to enable a diagnosis. The smaller the lesion, the more unlikely it is to yield diagnostic material. Nodules as small as 4 mm have yielded enough tissue for a pathologist to feel confident to diagnose nonsmall cell lung cancer [6], but size in and of itself is not a reliable indicator of success. Molecular testing agencies may require at least 100 viable tumor cells (author's experience), and no study has been published that equates a number of viable tumor cells to lesion size.

In these situations, either planning to offer thoracoscopic biopsy post-percutaneous lung lesion biopsy via same day or next day service or proceeding straight to thorascopic sampling with all its inherent risks is the proper route.

Technique

A coaxial technique of inserting a thinner sampling needle through a larger needle placed at the edge of the lesion has a number of theoretical advantages over tandem punctures. A number of samples can be obtained without re-puncturing the pleura (until such time as the introducer needle lumen develops a high degree of friction from the accumulation of coagulated blood). This theoretically improves speed and reduces pain and puncture-related complications. The depth of the sampling passes can be planned, and the stiffer, larger needle can enable additional torque and better steerability during manipulation. If a pneumothorax does occur, the introducer needle often will remain lodged in the lesion, allowing further samples to be obtained. A properly selected larger-bore needle can be used to obtain a biopsy gun specimen, insert a marker into the lesion for thoracoscopic resection or radiation therapy, or deliver a substance to caulk the tract (discussed below).

Each puncture site has a certain pressure above which air will leak into the pleural space. Performing a single puncture decreases the chances that one will leak at a relatively low intrathoracic pressure and cause a pneumothorax. Most small puncture wounds to the pleura leak at 10-40 mm Hg. A coughing fit will generate pressure in excess of 100 mm Hg, due to which all nonpatched and probably most patched punctures would leak. Visible tearing of the pleura allows leakage at a pressure of 1-2 mm Hg. [7]

A single puncture non-coaxial approach should be considered for high-risk circumstances, such as for a transcaval or trans brachiocephalic vein approach for lesions known to have hemorrhaged or suspected to be at high risk for hemorrhage and lesions with an associated prominent internal air-bronchogram in which there is an increased risk of air embolism.

Breath Holding

Respiratory volume should remain within the range of normal, quiet breathing. A puncture during a deep inspiration or expiration results in tension on the needle when the lung returns to its more normal status. This theoretically places greater stress on the pleura at the puncture site increasing the likelihood of a pleural tear. During sampling, care should be made not to create tension on the needle; ideally, the patient holds his/her breath while the radiologist is sampling. Patients are better able to hold a breath in inspiration than in expiration. Once a person can no longer hold breath, the tendency is to exhale if an inspiration was held but to inhale if an expiration was held. The latter is more likely to cause an air embolism.

Precautions

Minimizing the time that a needle is crossing the pleural space

If the needle is allowed to move with the motion of normal respiration, usually, no harm occurs. However, as the duration of the procedure increases, patients are eventually bound to move due to discomfort, to cough, or to place themselves at risk from needle motion otherwise. Delays, such as prolonging time to review the adequacy of tissue samples, from imaging to detect clinically silent intrathoracic complications or from personnel in the room not having proper radiation safety equipment, should be reduced to the absolute minimum.

Cough Suppression

Forceful coughing is likely to tear the pleura. Dramatic negative intrathoracic pressure occurs during inspiration prior to a cough, and high positive intrathoracic pressure occurs during a cough. This places the patient at risk for pneumothorax and for air embolism should the needle be uncovered with the tip in a vein. Procedure progress is halted during coughing episodes. Cough suppressant medication should be administered, or the irritant addressed. Otherwise, the procedure should be terminated.

Lung/Pleural Patch Technique

This technique entails caulking the pleural defect via the introducer needle at the completion of the procedure to prevent puncture site gas leakage. Different materials may be used, but the traditional approach involves using the patient’s own blood. If aerated lung has not been violated, a blood patch is not necessary. If multiple punctures have been made or a pneumothorax has already developed, then a blood patch theoretically is of lesser value. While the technique has been effective in lung biopsy models and and in real patients [7], no randomized trials comparing different types of blood patch techniques have been performed.

Post Procedure 

After blood patch placement and needle removal, some physicians roll the patient into the puncture-site-down position. This initial repositioning event should be performed by as many assistants as necessary to ensure that the patient remains passive and does not strain or perform a Valsalva maneuver. A forceful Valsalva maneuver is less likely to occur if the roll is performed while the patient lets his or her breath out. The needle removal and the rolling should take no more than a few seconds. Puncture-site-down positioning was first suggested by Zidulka in 1982. [8] It may work from a physiologic and/or mechanical mechanism. Physiologically, it makes the periphery of the dependent lung atelectatic, which should reduce local aeration. Mechanically, it tamponades the tract by creating visceral-parietal pleural apposition.

It is theoretically beneficial to prevent all activities that may elevate intrathoracic pressure, such as any type of breathing requiring the use of accessory muscles (e.g., laughing) or straining (e.g., sitting up in bed without assistance).

Oxygen saturation should be monitored. Supplemental oxygen interferes with this method of following the clinical impact of a small pneumothorax, so it should only be used when necessary. If a pneumothorax is known to be present, oxygen may be administered to facilitate resorption of the existing pneumothorax. The premise for how this may help is that a higher partial pressure of oxygen speeds diffusive resorption of trapped pleural air, which is comprised mostly of nitrogen (and carbon dioxide).

Follow-up Imaging

No chest radiograph need be obtained immediately after the biopsy unless symptoms or a falling oxygen saturation level suggest that a pneumothorax is present. Despite the best intentions of the technologist, the performance of a radiograph will probably entail at least some degree of patient straining or Valsalva maneuver. Oxygen saturation levels provide enough clinical information to delay the acquisition of the first image.

On the other hand, if an initially subclinical problem does exist, it is best to know about it before discharge. After several hours in the puncture-site-down position, the patient should be permitted to test activities similar to those that he or she would perform at home. A chest x-ray is then obtained. Upright expiratory images in at least two views (e.g., frontal and oblique) provide the most sensitive method for detecting interpleural air via plain film radiography. In the absence of serial images, new or continuing leakage cannot be distinguished from leakage that occurred immediately after the procedure and then stopped. Thus, follow-up imaging after the initial discovery of a pneumothorax should be made to determine leak stability.

Patient Discharge

The decision to discharge a patient, as opposed to admitting for observation or treatment, depends on the patient's condition, home situation, and home location. If there is more than a trivial pneumothorax or minor physical symptoms or signs, then only the following patients are candidates for discharge, given the small risk of death (e.g., from tension pneumothorax):

  • Can tolerate a larger pneumothorax,
  • Have a responsible family member who will be staying the night with the patient, and
  • Lives within range of transport to a medical facility or arrival of an ambulance within 10 to 15 minutes of symptom onset.

Complications

Percutaneous lung lesion biopsy is among the highest complication rate procedures performed by radiologists. The SIR suggests a threshold of up to 45% and 20% for pneumothorax rate and a chest tube insertion rate, respectively, prior to the trigger of a departmental review for creating a plan to lower the frequency of these complications. [9] The creators of the Johns Hopkins Surgical Risk Scale deemed percutaneous lung lesion biopsy a level 2 procedure due to it being a higher risk procedure than bronchoscopic biopsy, which is level 1. Not only is the chance of pneumothorax and hemorrhage lower with bronchoscopic biopsy, but the patient's airway is already secured from obstruction, which is not the case with percutaneous lung lesion biopsy. Percutaneous lung lesion biopsy is often performed on persons who are obese, elderly, highly emphysematous, and/or are ASA category 4 patients (e.g., patients who are unable to walk up a flight of stairs). Pre-notification of consultant medical specialists (e.g., an interventional pulmonologist or respiratory therapist) to be available on call at the first sign of trouble is prudent in cases where patients have these risk factors.

Deaths have occurred from percutaneous lung lesion biopsy. The mechanism of death is usually secondary to hemorrhage (all comer rate of about 1%, air embolism (all comer rate of less than 1%), cardiac event, or tension pneumothorax. [9] The SIR recommends a less than 3% threshold for "prolonged" hospital admission, having to exchange the chest tube, and/or pleurodesis [8], even though these decisions are usually outside of the radiologist's unilateral choice.

Pneumothorax

Pain from pneumothorax is not a consistent phenomenon across patients. Patients often experience pleuritic chest pain with a new even relatively small pneumothorax, although some patients are asymptomatic until a fairly impressive pneumothorax develops. The size of pneumothorax necessary to cause shortness of breath is extremely variable and depends on the underlying condition of the lungs. 

If a pneumothorax occurs prior to completion of tissue retrieval, the lung may need to be reinflated as the next step. Even notwithstanding a patient's clinical deterioration, if the no-longer-fixed-in-position lung does not move in a predictable manner, it may be impossible to anticipate the target lesion's future position at the time of next needle advancement. Also, the lung only may be able to be balloted, rather than punctured, by needle thrusts.

If air leakage is discovered during procedure follow-up, a minimum additional hour of puncture site-down positioning should be performed. Once imaging has shown that leakage has stopped, a period of upright positioning should be tried, followed either by discharge if no leakage occurs or repeating the cycle if leakage recurs. The cycle continues until the patient

  1. Can be discharged or
  2. Requires pleural drainage due to
    • Symptoms,
    • A pneumothorax exceeding about 30% [7], or
    • A recurring pattern of leakage.

Visual-only estimates of percent pneumothorax tend to be unreliable. The actual percent stenosis should be estimated using calipers and an evidence-based formula. [10] A pneumothorax that tracks down the lateral aspect of the chest will likely require evacuation.

Aspiration only of a pneumothorax may prevent chest tube placement in at least some patients with a substantial pneumothorax. Small gauge catheters (as small as 4 French) can be used inserted either via Seldinger or trocar technique. Alternatively, a large gauge needle (e.g., a Hawkins-Akins needle, which is a non-sharp needle with a sharp trocar) can be used. A pneumothorax can be evacuated most quickly via wall suction. Aspiration can also be used intentionally only to re-expand the lung temporarily (such as in the case of posterior-approach percutaneous lung lesion biopsy) thereby allowing for a catheter to be placed under less emergent conditions in a separate predetermined location for long-term use.

Hemoptysis 

Hemoptysis may be more likely to occur if puncturing a pulmonary cavity or enlarged bronchus, which are both associated with bronchial artery hypertrophy. Unusually bloody specimens, blood dripping out the introducer needle, and the formation of ground-glass attenuation in the lung prognosis the possible development of clinically significant hemoptysis.

If these findings develop, then less aggressive biopsy manipulations are recommended. Oxygen should be applied. The patient can be placed biopsy side down to prevent blood dripping through the bronchi into the other lung. Intubation if necessary should be performed with a dual lumen tube. If these maneuvers do not work, then consultation should be obtained for bronchoscopic tamponade of the lobar bronchus. Other therapies to consider include bronchial artery embolization, pulmonary artery embolization, and surgery.

If the patient had a decreased hemoglobin level or fluid volume to begin with, then administration of blood and/or IV fluids should be performed.

Air Embolism

Air embolism may occur from inspiration by the patient when the trocar has been removed from a needle tip located in a pulmonary vein and/or 2) iatrogenic creation of a bronchovenous fistula. The patient may become unconscious, have signs of a stroke, or undergo a seizure. 

The patient should be placed in the left lateral decubitus and/or Trendelenburg position to prevent air from exiting the left atrium prior to dissolving. Oxygen should be given to facilitate absorption of nitrogen in the bubbles.

Intubation and positive pressure ventilation may worsen venous air introduction in a bronchopleural fistula. Although most hospitals do not have decompression/hyperbaric chambers, if one were available this would be an appropriate time to use it.

Clinical Significance

The Centers for Disease Control (CDC) United States 2015 Cancer Statistics cites lung cancer as, by far, the most common cause of cancer death in the United States. Multiple society guidelines recommend that cancer treatment decisions be based on tumor histologic type and molecular markers. Although exceptions can be made, tissue diagnosis is the general rule prior to both curative and palliative therapy.

However, just as it is good medical care for physicians to see patients as persons and not as diseases, it is important for clinicians to understand that in order for tissue diagnosis to be obtained, biopsy procedures often require special considerations regarding the person undergoing the biopsy. The patient may not be able to lie still long enough to create an accessible avenue for the needle, may not be able to hold his/her breath consistently enough to enable access to the moving lesion given limitations in a hospital's CT fluoroscopy equipment, or may warrant specialist consultation to optimize pre-biopsy and post-biopsy care to prevent prolonged hospitalization or even severe permanent injury secondary to complications.

For these reasons and because most experienced interventional radiologists can reach a target of at least 5 mm diameter and less than 15 depth, the commonly asked question "Can the lesion be biopsied?" is generally not an appropriate question. The following three questions are more appropriate to decision making for patient care:

  • "Has the lesion reached a size allowing a reasonable chance at a tissue yield, or is it more reasonable to wait to allow the lesion to grow in anticipation that a diagnosis will still likely be achieved prior to potential metastasis?"
  • "Assuming that biopsy now appropriate, how should the physicians and patient work together to optimize the patient medically and psychologically to improve the likelihood of a safe and successful biopsy?"
  • "Anticipating that the biopsy attempt may not yield an adequate amount of tissue, what will plan B be?"