Dry Medical Thoracoscopy with Artificial Pneumothorax Induction Using Veress Needle

Article information

Tuberc Respir Dis. 2025;88(1):181-189

Publication date (electronic) : 2024 November 14

doi : https://doi.org/10.4046/trd.2024.0029

Nai-Chien Huan, F.R.C.P.^,1, Sze Shyang Kho, M.R.C.P.², Larry Ellee Nyanti, M.R.C.P.I.^1,3, Hema Yamini Ramarmuty, M.R.C.P.¹, Muhammad Aklil Abd Rahim, Dr.P.H.⁴, Rong Lih Ho, M.R.C.P.¹, Shan Min Lo, M.R.C.P.¹, Siew Teck Tie, F.R.C.P.², Kunji Kannan Sivaraman Kannan, F.R.C.P.¹

¹Department of Respiratory Medicine, Queen Elizabeth Hospital, Kota Kinabalu, Malaysia

²Division of Respiratory Medicine, Department of Medicine, Sarawak General Hospital, Kuching, Malaysia

³Medical Department, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia

⁴Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia

Address for correspondence Nai-Chien Huan, F.R.C.P. Department of Respiratory Medicine, Queen Elizabeth Hospital, Kota Kinabalu, Malaysia E-mail naichien_1@yahoo.com

Received 2024 March 12; Revised 2024 July 27; Accepted 2024 November 11.

Abstract

Introduction

Pleural tissue biopsies are necessary to establish a definitive diagnosis for pleural pathologies when initial investigations are inconclusive [1]. This is achievable through medical thoracoscopy (MT), also referred to as local anaesthesia thoracoscopy or pleuroscopy, a minimally invasive procedure that facilitates comprehensive examination of the pleural space under conscious sedation. In the absence of significant pleural effusion, conventional MT is often not feasible due to the risk of lung injury. Dry MT addresses these concerns by inducing an artificial pneumothorax via needle insufflation [2] or blunt dissection [3].

The Veress needle, invented in 1932 by Hungarian internist Janos Veres, was initially used to induce pneumothorax as a treatment for tuberculosis, which was a primary method for managing the disease at the time. However, with the advent of effective anti-tuberculosis drugs, the needle’s use for this purpose became obsolete. In more recent years, the Veress needle has found a new role in the field of surgery, primarily for creating pneumoperitoneum before laparoscopic procedures. It is not commonly reported in dry MT settings, with just one local, single-centre study documenting its use in the literature [4]. In this study, we reviewed cases from our centres where dry MT was performed, employing thoracic ultrasonography (TUS) to identify entry sites with visible lung sliding prior to inducing pneumothorax with a Veress needle. Our study aimed to assess the performance and safety of the Veress needle in dry MT and to describe the clinical indications, biopsy techniques, and histological outcomes observed.

Materials and Methods

3. Procedure details

1) Pre-procedural planning and case selection

Potential MT candidates from general medical and respiratory wards, as well as outpatient respiratory clinics, were assessed by respiratory consultants or fellows skilled in TUS. Common indications for MT included, but were not limited to, undiagnosed exudative pleural effusions or other pleural pathologies where preliminary procedures such as thoracentesis or percutaneous pleural biopsies were inconclusive, and therapeutic needs such as chemical pleurodesis, mechanical adhesiolysis, and guidance for indwelling pleural catheter placement.

During the review, patient characteristics such as demographics, comorbidities, and performance status, along with TUS findings including lung sliding, pleural effusions, and other pleural pathologies such as nodules, masses, and thickening, were recorded. Any procedural contraindications, including bleeding diatheses, were also assessed. Anticoagulants were withheld before the procedure as per recommended guidelines, and patients deemed suitable for MT were placed on a procedural list within 2 weeks.

The inclusion criteria for this study were: (1) all adult patients undergoing dry MT for undiagnosed exudative pleural effusion from December 1, 2018, to January 31, 2024 and (2) American Society of Anaesthesiologists class 3 and below. The exclusion criteria were: (1) non-adult patients (18 years old and below) and (2) patients who underwent conventional MT without the use of a Veress needle for pneumothorax induction.

2) Procedural characteristics

MT procedures were conducted in operating theatres, either as daycare outpatient or inpatient setups at both our centres. On the day of the procedure (or the day before for inpatients), essential blood investigations, including full blood count, coagulation profile, and renal profile, were taken, and reviewed. TUS assessment was performed in the lateral decubitus position with the affected hemithorax facing up, recording key TUS findings. The optimal position for skin incision and subsequent chest trocar insertion was identified and marked on the chest wall, followed by obtaining written informed consent for MT.

For patients considered unsuitable for MT and those for whom pneumothorax induction with a Veress needle was predicted to be unsuccessful (due to the absence of lung sliding or prominent adhesions on TUS at the mid-axillary line), MT was either cancelled or converted to percutaneous TUS-guided biopsies if technically feasible. For patients with an adequate amount of pleural effusion (more than 3 cm of effusion depth at the mid-axillary line), the MT procedure was performed without prior pneumothorax induction. Pneumothorax induction was conducted using a Veress needle (26120JL, length 13 cm, diameter 2.1 mm; Karl Storz, Tuttlingen, Germany) (Figure 1) for patients with adequate lung sliding on TUS at the mid-axillary line, but with minimal pleural effusion (defined as less than 3 cm in depth at the mid-axillary line) (Figure 2).

Fig. 1.

A Veress needle (Karl Storz) with its components labelled. The sharp tip is used to penetrate through the chest wall layers till it breaches the parietal pleura into the pleural cavity. Upon entering the pleural cavity, due to loaded spring action, the blunt tip will automatically remerge beyond the sharp tip, thereby protecting underlying lung structures from injuries. The stopcock can be used to adjust the amount of air that will go through the needle. The air entry point is pointed with an orange arrow.

Fig. 2.

Thoracic ultrasonography (TUS) image for a patient that is suitable for dry medical thoracoscopy. There is no pleural effusion at the safety triangle but a pleural sliding sign was present.

3) Sedation and pneumothorax induction with Veress needle

Intravenous sedation with midazolam (1 to 2 mg) coupled with either fentanyl (20 to 50 μg) or pethidine (50 to 100 mg) was administered, followed by local anaesthetic infiltration (up to 20 mL of 1% lidocaine) at the site of the chest wall incision. To minimize procedural discomfort and pain, care was taken to ensure adequate anaesthesia of the skin, subcutaneous layers, intercostal muscles, and parietal pleura. Local anaesthesia was infiltrated under TUS guidance to prevent injury to the visceral pleura. Artificial pneumothorax induction was then performed using a Veress needle under direct TUS guidance. The Veress needle was held like a dart and inserted perpendicularly through a small skin incision in the pre-marked area at the mid-axillary line. We favour an in-plane approach with ultrasound guidance to allow visualization of the entire needle during the insertion process (Figure 3A).

Fig. 3.

Steps of performing dry medical thoracoscopy with a Veress needle. (A) The Veress needle is inserted perpendicularly to the chest wall under direct ultrasound guidance. (B) Performing the saline drop test to confirm that the tip of the Veress needle is within the pleural cavity. (C) Insufflating air into the pleural cavity to expedite pneumothorax formation. (D) Forceps dilatation of chest wall incision site. (E) Trochar placement to allow entry of medical thoracoscope. (F) Performing medical thoracoscopy using a semi-rigid thoracoscope after successful induction of pneumothorax.

The Veress needle was carefully advanced until a “give” sensation was felt (Figure 3B), followed by the insufflation of an additional 200 to 400 mL of atmospheric air into the pleural cavity using a 50 mL syringe to expedite pneumothorax formation (Figure 3C). Successful needle placement and pneumothorax induction were confirmed by four methods: (1) direct visualization of the tip of the Veress needle within the pleural cavity; (2) the “hissing” sound produced as atmospheric air entered the pleural cavity via the Veress needle due to negative intrathoracic pressure; (3) the absence of a sliding sign on TUS upon pneumothorax induction; and (4) a positive saline drop test (Figure 3B). The saline drop test, also known as the hanging drop test, involved instilling a few drops of saline over the tip of the Veress needle upon insertion into the pleural cavity. A positive test is indicated by the disappearance of saline drops into the shaft of the Veress needle with respiration.

4) Medical thoracoscopy procedure

Upon successful pneumothorax induction with a Veress needle, a chest wall incision was made using a scalpel, followed by forceps dilation of the incision site (Figure 3D), trocar placement (Figure 3E), and subsequent introduction of a semi-rigid thoracoscope (LTF-160, Olympus Medical, Tokyo, Japan) into the pleural cavity, following the standard protocol (Figure 3F). At least 10 forceps biopsy samples were taken for diagnostic purposes. If deemed necessary by the proceduralist, cryo-biopsies using flexible single-use cryoprobes (probe diameter 1.7 mm, Erbe, Marietta, GA, USA) or rigid forceps biopsies were performed. Therapeutic procedures such as fluid drainage, mechanical adhesiolysis, talc instillation, and indwelling catheter placement were carried out according to the treating clinician’s decision. Chest drains were inserted post-procedure to facilitate lung re-expansion and patients were typically discharged 1 to 2 days post-procedure with follow-up clinic appointments scheduled in 2 weeks.

Results

1. Demographics and pre-procedural characteristics

We reviewed a total of 31 cases, comprising 20 male patients and 11 female patients. The pleural effusions included 23 right-sided and eight left-sided effusions. Among these cases, 30 were performed using a semi-rigid thoracoscope, while only one utilized a rigid thoracoscope, anticipated due to a thickened pleural lining identified during TUS. Indications for dry MT included cytology-negative pleural effusion (n=18), effusion associated with extrapulmonary malignancies (n=6), pleural thickening or mass on computed tomography (n=4), and known malignant effusion requiring more tissue samples for further analysis (n=3). Two cases had previous video-assisted thoracoscopy, and one had prior talc pleurodesis. Only two patients received oxygen supplementation before dry MT, with one on a high-flow nasal cannula at a FiO₂ of 0.4 and 40 L of oxygen per minute and the other using nasal prongs delivering 3 L of oxygen per minute. Characteristics of the effusion at the entry point varied, with effusion only at the dependent site (n=19), no effusion (n=10), and effusion at the entry site less than 3 cm (n=2). Only two of the 31 cases exhibited partial lung sliding. A detailed breakdown of pre-procedural characteristics is provided in Table 1.

Table 1.

Pre-procedural characteristics and associations with procedure success (total patient n=31)

2. Procedural characteristics

In terms of sedation, midazolam was universally used in all patients, while the second agent varied between pethidine (50 to 100 mg) and fentanyl (25 to 50 μg). Complete pneumothorax was successfully induced in all but six cases, achieving a technical success rate of 80.6%. Even in those six cases without complete lung collapse post-pneumothorax induction, we successfully performed parietal pleura biopsies. The primary reasons for the failure of pneumothorax induction were adhesions causing limited manoeuvre space (n=4), and thickening over the visceral pleura (n=2). Rigid forceps were used in one case, and a cryo-probe in two cases, while the remainder employed flexible forceps. There were no significant complications, with only one case (3.2%) of self-limited bleeding following pleural cryo-biopsies. Table 2 provides a detailed description of procedural characteristics.

Table 2.

Procedural descriptions, outcome, and associations with procedure success (total patient n=31)

Discussion

Traditionally, patients with pleural lesions but no effusion undergo video-assisted thoracoscopic surgery (VATS) under general anaesthesia and single-lung ventilation [3]. However, limited cardiorespiratory reserves and significant comorbidities, which are common in these patients, may make general anaesthesia and VATS exceedingly risky [5,6]. Additionally, VATS involves greater costs and longer hospital stays compared to MT [7]. Dry MT, which requires only local anaesthesia and moderate sedation, offers a viable alternative. Techniques for dry MT include the use of a Veress needle, blunt dissection, and pleural stripping with Kocher forceps [8], thoracoport with a 0º camera lens [9], blunt-point scissors [10], and Boutin needle [2,11]. In a Malaysian cohort study of 210 MT cases, the Veress needle was selectively used in cases with minimal effusion, although the precise number of such cases was not specified [4]. No direct comparison studies exist between different devices capable of inducing pneumothorax prior to MT.

The Veress needle is used by surgeons to induce pneumoperitoneum before laparoscopic surgeries, providing a solid foundation for its use in the induction of pneumothorax [12]. The Veress needle is available in various lengths and diameters, and in both disposable (endopath insufflation needle, Johnson & Johnson MedTech, Warsaw, IN, USA) and reusable (Veress Pneumoperitoneum needle, Karl Storz) forms. It operates via a spring-loaded mechanism that includes both a sharp and a blunt tip [12]. The sharp tip pierces the skin, subcutaneous tissue, and intercostal muscle layers until it penetrates the parietal pleura into the pleural cavity. Upon entry into the pleural cavity, the blunt tip automatically extends beyond the sharp tip, thus safeguarding underlying lung structures from injuries. This feature of the needle is particularly valuable in pleural medicine, given that many patients undergoing MT have pre-existing lung parenchymal diseases such as lung bullae or emphysema, which are prone to traumatic injuries during procedures.

Published success rates for dry MT have varied, depending on the centre and specific descriptors of success. In a British cohort of 77 cases, 87% demonstrated sufficient pneumothorax induction [2], with failures attributed to adhesions on TUS. An Italian cohort of 29 cases using blunt-point scissors achieved a pneumothorax induction rate of 100% [10]. In another British cohort of 38 cases using the Boutin needle, the successful pneumothorax induction rate was 71.1% [11], with failures attributed to adhesions on TUS (n=10) and trochar placement into the lung (n=1). In a Japanese cohort of 16 dry MT cases, dissection of the parietal pleura with a Kocher clamp achieved a diagnostic accuracy of 93.8% [8]. Additional benefits of dry MT include shorter durations of post-operative chest tube drainage, due to the absence of effusion, which facilitates quicker lung re-expansion [8]. Unfortunately, data on this aspect were not collected in our cohort. Complication rates for dry MT are relatively low and include trochar placement into the lung [11], mild chest pain [8], and transient hypoxia [8]. Both the Italian and one British cohort reported no complications [10]. Similarly, we observed no complications directly related to Veress needle use in our study. Carbon dioxide embolism, a rare complication of Veress needle use during laparoscopic cholecystectomy, typically results from incorrect injection into large vessels or directly into a highly vascularised solid organ [13].

TUS plays a crucial role in selecting the appropriate site for pneumothorax induction prior to MT. Active lung sliding on TUS excludes significant pleural adhesions that could hinder trochar insertion or inhibit lung collapse [8]. In such cases, VATS surgery is recommended [8]. Linear-type ultrasonography is preferred for detecting mobility between the parietal and visceral pleura due to its ability to produce high-resolution images of structures close to the body surface [8]. In our study cohort, two patients experienced only partial lung collapse after pneumothorax induction, yet MT exploration was still feasible, and pleural biopsies were diagnostic. Both patients exhibited only partial lung sliding on TUS before MT. This observation is consistent with previous studies by Corcoran et al. [2], which showed that limited lung sliding is the primary cause of unsuccessful pneumothorax induction using the Boutin needle. Other critical factors for successful dry MT include effective analgesia [8]. Without the ‘weight effect’ of pleural fluid, lung re-expansion can occur more quickly in dry MT. Adequate sedation and analgesia enhance procedure tolerability by reducing patient discomfort, coughing, and rapid breathing; these factors accelerate lung re-expansion and may hinder thorough inspection of the pleural cavity and biopsy collection. Unfortunately, we did not document the time between initial pneumothorax and subsequent lung re-expansion in our patients.

Studies on pre-VATS TUS indicate that TUS has high specificity and can serve as a rule-in test for detecting pleural adhesions before thoracic surgeries [14,15]. Moreover, Lichtenstein previously classified TUS lung sliding amplitude as “normal” if >10 mm, “significantly reduced” if between 4 and 10 mm, “quite abolished” if between 1 and 3 mm, and “fully abolished” if no visible pleural movement is present (0 mm) [16]. This categorization has not been utilized in the setting of dry MT. Consequently, it is unclear how the severity of “partial lung sliding” (described in some of our cases), lung adhesion, or pleural thickening may impact the likelihood of lung collapse in dry MT. In the Italian cohort, intra-procedural adhesions are categorized as single or multiple; however, these adhesions did not obstruct endoscopic exploration and biopsy [10]. Importantly, only patients with evident lung sliding at the entry site were included. Additionally, our findings suggest that a right-sided procedure and the absence of lung-to-chest wall adhesion favour successful pneumothorax induction. These results should be interpreted with caution due to the limited sample size, which affects the generalisability. This concern is further supported by the broad CI, making the interpretation and utility of the OR uncertain. Moreover, technical success rates may differ depending on the experience and skill levels of the operators. Nevertheless, we believe these results provide a valuable baseline description and a foundation for developing further hypotheses to aid future research on the subject and to inform clinical practice recommendations.

In conclusion, despite being a retrospective study involving a limited number of cases, our study suggests that TUS-guided dry MT using a Veress needle is technically feasible and safe when performed by experienced MT practitioners skilled in TUS. None of our patients experienced any significant injuries or developed complications related directly to the use of the Veress needle. Additionally, the Veress needles used in our centres are reusable and thus autoclavable, making them cost-effective in resource-limited settings. Further cost-effectiveness analyses are warranted in the future.

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