Buttonhole LASER pulmonary metastasectomy: an innovative parenchyma preserving technique

Abstract

With advances in systemic anticancer therapies, pulmonary metastasectomy is being increasingly employed for local disease control while aiming to preserve lung parenchyma, anatomy, and function with complete (R0) resection. We introduce an innovative neodymium-doped yttrium aluminum garnet (Nd-YAG) light amplification by stimulated emission of radiation (LASER) approach for peripherally located, deep-seated, and fissural lesions, utilizing the lung’s natural tongue-like configuration at the edges. This method involves cylindrical excision around the nodule, creating a buttonhole from one surface to the other. This approach minimizes parenchymal loss and maintains anatomical integrity, ensuring adequate lung expansion. We refer to this as the Nd-YAG LASER buttonhole pulmonary metastasectomy. Ten patients who underwent Nd-YAG LASER buttonhole pulmonary metastasectomy for synchronous and metachronous lesions at a tertiary oncology center in India between October 2023 and December 2024 were identified from a prospective database. Data was collected retrospectively from patient records from PARAS software, operative recordings, and clinical imaging systems. Between October 2023 and December 2024, 62 patients underwent Nd-YAG LASER–assisted pulmonary metastasectomy, with 10 patients undergoing buttonhole metastasectomy based on specific criteria. The procedure demonstrated efficacy in managing multiple and bilateral metastases, with 83.3% of bilateral cases completed in a single stage. In this cohort of 10 cases, 43 metastatic lesions were resected, out of which 27 were excised using LASER, including 14 via the buttonhole approach. This technique achieved precise excision with minimal parenchymal loss, maintaining a mean clear margin of 2.78 mm. Postoperative recovery was uneventful, and all patients remained disease-free at follow-up. For deep-seated peripheral lung lesions in the outer third of the lung, especially near the mediastinal pleura, diaphragm, or fissures, Nd-YAG LASER–assisted buttonhole pulmonary metastasectomy serves as a safe and effective alternative to LASER coring, stapled wide wedge resection, or segmentectomy. This technique enhances lung parenchymal preservation while allowing for potential future redo metastasectomies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-025-01988-7.

Introduction

Pulmonary metastasectomy (PM) has been shown to prolong survival and achieve a cure in various cancers [1]. Advancements in thin multislice computed tomography and the shift from open to video-assisted thoracoscopic surgery (VATS) have enhanced surgical precision and prioritized complete tumor resection while preserving functional lung parenchyma, with possible redo PM in the future. Deep-seated lung lesions require deep coring with energy sources or wide wedge stapler excision, with significant lung parenchymal loss. These approaches also limit the feasibility of redo PM [2]. To prevent such challenges and to preserve lung anatomy post-metastasectomy, we modified our technique for specific lesion sites. Since adopting the neodymium-doped yttrium aluminum garnet (Nd-YAG) light amplification by stimulated emission of radiation (LASER) PM technique in October 2023 at our center, we have refined our approach to LASER coring for deep-seated parenchymal outer-third lesions along the diaphragm, mediastinal pleura, and fissures. Leveraging the lung’s natural tongue-like configuration at these sites, this study introduces “buttonhole pulmonary metastasectomy” where parenchyma surrounding the nodule is excised cylindrically from one surface to the opposite, thus minimizing lung tissue loss while preserving anatomical integrity for lung expansion.

Material and methods

Study design

This retrospective study reviewed data of 10 patients who underwent thoracoscopic-assisted mini-thoracotomy Nd-YAG LASER PM via buttonhole technique at a tertiary oncology center in India from October 2023 to December 2024. Oral and written consent for surgery and publication was taken after ethical approval. Data, including patient demographics, comorbidities, primary tumor and pulmonary metastasis characteristics, surgical details, and postoperative outcomes within 30 days, were collected retrospectively. Total lesion volume and volume of lung parenchyma resected were measured based on the final histopathological analysis.

This procedure was specifically applied to cases where preoperative computed tomography scans indicated that the lesions were located in the outer third of the lung, away from major vessels and airways, and intraoperative assessment revealed that the nodules were deep-seated along the periphery, with one lung surface in contact with the anterior or middle mediastinal pleura, diaphragm, or along the fissure in the outer third (Fig. 1). The peripheral, tongue-like configuration of the lung made it well suited for a buttonhole excision of these lesions. Rolle et al. [2] noted that a 3-mm safety margin, along with an additional 5-mm coagulation zone, was sufficient to reduce the local recurrence rate during LASER metastasectomy. Taking this into account, a minimum margin of 1 cm was established as the cutoff for this procedure.

Fig. 1.

Diagrammatic representation of sites suitable for buttonhole laser metastasectomy (marked with a blue circle). Deep-seated lesions in the lung’s outer third, with surfaces contacting the diaphragm, anterior/middle mediastinal pleura, or pericardium and fissure

Operative technique

The procedure was performed under general anesthesia, with single-lung ventilation using a double-lumen endotracheal tube. The patient was positioned in a lateral decubitus position and the table was extended along the chest to facilitate adequate rib space opening. A 10-mm port incision was made for diagnostic thoracoscopy along the posterior axillary line at the seventh intercostal space and a 30° 10-mm rigid scope was introduced. Subsequently, a 7-cm anterolateral skin utility incision admitting four stretched fingers was made at the fourth or fifth intercostal space (Fig. 2a), followed by serratus muscle splitting and intercostal muscle cutting, aligned along the oblique fissure. Metallic chest wall retraction was applied to just easily pass four stretched fingers for digital palpation of lesion and introduction of Nd-YAG LASER probe (Fig. 2b, c). Following this, a medium-sized wound protector was placed to maintain sterility and tension at the wound site (Fig. 2b). Complete hilar mobilization was done, starting from the inferior pulmonary ligament to the suprahilar area both anteriorly and posteriorly allowing direct palpation of the lower lobe’s segments, middle lobe segment, and lingular segment along the utility wound. After localizing all lesions with cautery tattoos, those meeting the criteria for buttonhole LASER PM were selected. To prevent injury from LASER energy due to heat dissipation, saline-soaked gauzes were placed surrounding the lung. LASER-assisted surgery (LAS) was performed using Nd-YAG, Nd: Y3 Al5O12 LASER (1320 nm; Limax, KLS Martin GmbH & Co. KG, Tuttlingen, Germany). The camera type posed no compatibility issues with the LASER. Surgeons and operating room staff adhered to all necessary LASER safety protocols, including the use of appropriate eye protection and personal protective equipment throughout the procedure. The hand-held LASER device was then introduced with simultaneous smoke extraction. A red pilot light helped guide the LASER beam onto the lung tissue. Buttonhole Nd-YAG LASER PM was done by excision of lung parenchyma surrounding the nodule in a cylindrical fashion till the opposite lung parenchymal surface was breached to allow for complete en-bloc removal of the nodule. LASER ablation enforcement of the lung parenchyma was done to achieve hemostasis and pneumostasis followed by approximation of the opposite lung parenchyma surface with absorbable monofilament 3/0 polydioxanone interlocking suture creating a buttonhole-like configuration (Video 1). This approach ensured sufficient expansion of the lung’s peripheral alveoli for effective oxygen exchange, preserved lung parenchyma, and maintained lung anatomy with minimal distortion. Intraoperative air leak and adequate lung expansion were confirmed using a water leak test. A single large-bore pleural drain (typically a 28-Fr intercostal drainage tube) was inserted in the pleural cavity. The intercostal drain was removed by postoperative day 1 or 2 depending on the number of nodules excised and the chest x-ray showed an expanded lung with serous color drainage fluid with a threshold of 5 ml/kg body weight.

Fig. 2.

a Diagnostic thoracoscopy with utility incision admitting four fingers. b Utility incision with metallic retractor protected by wound expander for digital palpation and introduction of laser probe. c Nd-YAG laser probe

Results

Between October 2023 and December 2024, 62 patients underwent Nd-YAG LASER–assisted PM for both synchronous and metachronous lesions. Among them, 10 patients were selected for buttonhole metastasectomy based on specific criteria. The patients’ demographic and clinical characteristics are outlined in Table 1. The average age was 51.8 years, ranging from 31 to 65, with 70% of the patients being male. Synchronous and metachronous lesions were equally distributed, with colorectal (n = 4) and renal (n = 3) being the most common primary sites. Other primary sites included breast, testes, and bone (n = 1 each). Seventy percent of patients received preoperative therapy, including chemotherapy, radiotherapy, or immunotherapy. Nine out of 10 patients had multiple metastases, with 40% presenting with four or more metastases, either unilaterally or bilaterally. The total number of metastatic lesions encountered was 43 in 10 patients excised using either LAS or the stapled wedge approach (Table 1).

Table 1.

Patient demographics, clinical and surgical characteristics

Variable	Frequency (n = 10)
Age, mean (range), years	51.8 (31–65)
Gender
Male	7
Female	3
Primary malignancy site
Colorectal carcinoma	4
Renal	3
Bone	1
Breast	1
Testis	1
Side
Right	4
Left	0
Bilateral	6
Preop. chemotherapy and/or radiotherapy and/or immunotherapy
Received	7
Not received	3
Pulmonary metastases
Solitary	1
Multiple
2–3 pulmonary metastases	5
> 4 pulmonary metastases	4
Bilateral metastasectomy
Single staged	5
Two staged	1
Synchronous	5
R0	10
R1	0
Lymph node involvement	1/9
Histology-wise distribution
Adenocarcinoma	4
Squamous cell carcinoma	1
Chondrosarcoma	1
Clear cell RCC	2
Number of lesions	14
Bronchopulmonary segment involved
S1	1 (right)
S3	1 (right)
S5	1 (right)
S7	3 (right)
S7–8	3 (left)
S10	5 (right)
Mean nodule size in centimeters	1.6 × 1.1 × 0.5
Mean excised specimen in centimeters	2.3 × 1.6 × 0.8
Nodule/specimen ratio	0.3
Margin in millimeters	2.78
Air leak	0
Basal pneumonia	2
ICD removal in days	2.6 (1–5)
Hospital stays in days	4 (3–6)

Nd-YAG LASER metastasectomy was performed for 27 lesions (62.8%) out of which 14 nodules were excised using a buttonhole approach (51.9%). Ten out of 14 nodules excised using the buttonhole approach were positive for metastatic disease. The most common histology encountered was adenocarcinoma (n = 4), followed by clear cell renal cell carcinoma [RCC] (n = 2). One patient with clear cell RCC was diagnosed to have a second primary on PM with squamous cell carcinoma. The most involved bronchopulmonary segments (S) were the S10 segment (n = 5) followed by S7 and left S7–8 segments (n = 3 each).

Among the lesions excised by the buttonhole approach, the mean size of the nodule was 1.59 cm × 1.07 cm × 0.52 cm, and the mean size of the specimen was 2.28 cm × 1.56 cm × 0.82 cm, with a mean documented clear margin of 2.78 mm (range 1–5 mm). The nodule/specimen ratio was calculated as 0.29. The most common complication in the early postoperative period was basal atelectasis (n = 2) which resolved with spirometry, chest physiotherapy, and deep breathing exercises. The mean duration of hospital stay and chest drain removal was 4 days and 2.6 days, respectively. Of the 10 patients in the study, 8 underwent a sandwiched procedure (LAS with buttonhole technique and stapled wedge metastasectomy), while only 2 had buttonhole LASER metastasectomy alone. Therefore, the overall average operative parameters—such as operative time, blood loss, and transfusions—do not accurately reflect outcomes of the buttonhole technique alone. These values are not calibrated specifically for it. Notably, no patient required a blood transfusion intraoperatively or postoperatively, and the mean operative time was 127.2 ± 27.8 min. All 10 patients were disease-free during their last follow-up.

Discussion

In 1967, Minton and colleagues [3] first reported the use of 1064-nm Nd-YAG LASER in rabbit lung metastasectomy. Since then, numerous studies have expanded the application of LASER in PM. Nd-YAG LASER–assisted PM is a well-established technique. The role of PM is supported by various retrospective data and meta-analyses showing a survival benefit [1–3]. It allows for the removal of a greater number of metastases compared with mechanical staplers while preserving healthy lung parenchyma and yielding recurrence rates similar to conventional mechanical staplers [4, 5]. The Nd-YAG LASER PM technique preserves lung parenchyma and anatomy, enabling repeat surgeries in recurrences. This method offers the advantage of avoiding wide wedge resections and large coring of lung tissue, which can lead to sizable residual cavities and, when sutured, may distort lung anatomy, hindering proper lung expansion. Additionally, the Nd-YAG LASER buttonhole technique circumvents segmental lung resections in certain cases where mechanical staplers were previously used.

Our study indicates that the buttonhole technique is particularly effective for deep-seated lesions located in the outer third of the lung, especially those in contact with the diaphragm, anterior and middle mediastinum along the pericardium, or the fissure. The applicability of this method to other sites depends on the surgeon’s assessment during the procedure, considering the principle of avoiding deep core excisions that result in large residual spaces and preserving lung anatomy for adequate expansion. The findings of our study support the advantages of Nd-YAG LASER PM, performed on 27 lesions in 10 patients. Of these, 14 nodules were excised using the buttonhole approach (51.9%). The nodule/specimen ratio for the buttonhole approach was calculated to be 0.29, which is higher than the ratio of 0.11 observed in a retrospective study by Darlong et al. [6], indicating less excised tissue and greater lung preservation. The most common bronchopulmonary segments involved in our study were S10 (n = 5) followed by S7 and left S8 (n = 3 each) utilizing the tongue-like configuration of the lung at the periphery. The belief that circumferential resection of the lesion renders the peripheral rim of the lung non-functional is inaccurate, as demonstrated by our approach. In stapled wedge resection, rigid titanium clips limit the expansion of lung tissue at the stapling site [7].

In our study, the average margin of the resected specimens was 2.78 mm. Local recurrence at the surgical margin after PM occurs in 9–31% of cases, even when histopathologically confirmed complete resections (R0) are achieved [8]. Patients with good functional status may be candidates for repeat resections [9]. LASER-assisted metastasectomy has shown a lower recurrence rate of 3.2%, which is attributed to the protective coagulation zone created during the procedure [10]. This 5-mm coagulation rim, formed by vaporization and elevated temperatures, destroys residual tumor cells, thereby improving the safety margin around resected nodules [2]. This sterilization effect of LAS is also seen with the buttonhole approach, as evidenced by the disease-free status of all 10 patients at the last follow-up.

Limitation

The extent of benefits could not be objectively quantified since patients lacked follow-up pulmonary function tests, and no direct comparison with segmentectomy or stapled wedge excision was possible. The operative parameters reported are not exclusive to the buttonhole technique, limiting their applicability in evaluating the technique’s standalone efficacy.

Conclusion

For deep-seated peripheral lung lesions in the outer third—especially those along the diaphragm, mediastinum, pericardium, or fissure, Nd-YAG LASER–assisted buttonhole PM provides a safe, effective alternative to traditional LASER coring, stapled wide wedge resection, or segmentectomy. This technique preserves lung parenchyma, allowing for potential repeat PM in cases of recurrence.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Laleng Mawia Darlong, Naveen Kumar Kushwaha, Arnab Chakraborty, Prerit Sharma, and Neha Garg. The first draft of the manuscript was written by Naveen Kumar Kushwaha, and all authors commented on previous versions of the manuscript. The final manuscript was written by Lalengmawia Darlong and Naveen Kumar Kushwaha. All authors read and approved the final manuscript.

Funding

None.

Data availability

Data available on request.

Declarations

Ethical approval

The Rajiv Gandhi Cancer Institute and Research Centre Ethics Committee (RGCIRC/IRB-BHR/84/2023, dated August 28, 2023) approved the study. Written informed consent was obtained from all the participants, and precautions were taken to maintain confidentiality.

Statement of human and animal rights

The study has been performed in accordance with the ethical standards as laid down in the 1964 declaration of Helsinki and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.

Consent for publication

Patients’ consent for publication of their case details and images in a scientific journal for educational purpose was obtained.

Conflict of interest

None.