Nghiên cứu ứng dụng phẫu thuật nội soi một lỗ trong điều trị u trung thất ttta

VIETNAM MINISTRY OF MINISTRY OF DEFENCE The study was conducted at EDUCATION AND TRAINING 108 Institute of Clinical Medical and Pharmaceutical Sciences 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES NGO GIA KHANH Scientific mentor: NGUYEN HUU UOC, Assoc Prof., PhD TRAN TRONG KIEM, Assoc Prof., PhD RESEARCH APPLICATION OF SINGLE-PORT VIDEO ASSISTED THORACIC SURGERY IN TREATMENT OF MEDIASTINAL TUMORS Specialty: Surgery/ Thoracic surgery The thesis will be defended at Institute level Thesis Assessment Committee at ID : 9720104 108 Institute of Clinical Medical and Pharmaceutical Sciences At .: , , 2023 DOCTORAT THESIS SYNOPSIS The thesis can be studied via: Vietnam National Library 108 Institute of Clinical Medical and Pharmaceutical Sciences Library Hanoi – 2023 ABSTRACT Video assistant thoracic surgery has been formed and constantly developed over the past 20 years, the instruments and techniques are increasingly improved and perfected From assisted thoracoscopic surgery to total thoracoscopic surgery with multiple port (Multiport-VATS) and more recently single-port thoracoscopic surgery (Uniport-VATS) is being considered as a new development trend of Video assistant thoracic surgery Unlike conventional laparoscopic surgery, single port thoracoscopic surgery only uses a small incision in the intercostal space to access the pleural space, the instruments and camera are placed in parallel Similar to direct view in open surgery, all instruments pass through one working port and surgeon's twohanded operations on the same plane Single-port VATS was first introduced by Gaetano R in 2004 but was limited to a minor procedure of thoracic surgery, then expanded in indications and developed by Diego G R Up to now, this technique has been widely accepted and practiced by thoracic surgeons around the world Many studies have shown that Single-port VATS is associated with a reduced risk of adverse events and has an advantage in postoperative pain relief when compared with conventional Multiport-VATS For the treatment of mediastinal tumors, Single-port VATS is indicated for cases where the tumor is small in size, has not invaded surrounding tissues, in many reports confirming this technique is safe and feasibility, the short-term results is not inferior to current thoracoscopic techniques Recently, Single-port VATS for mediastinal tumor has been performed at some thoracic surgery centers in Vietnam, initial results are very encouraging, some studies have been conducted but only limited to case reports without systematic studies on this issue With a new technique, it is necessary to conduct large sample size studies to make recommendations on the selection of appropriate subjects and to evaluate the safety, feasibility and effectiveness of the method to widen the scope of application and make this technique routine Stemming from these practical demands, we conducted the research: “The application of single-port video assisted thoracic surgery in the treatment of mediastinal tumors” at Bach Mai hospital with the following two objectives: Evaluate clinical and diagnostic imaging features of MTs treated with single-port thoracoscopic surgery Evaluate outcomes of single-port thoracoscopic surgery in the treatment of MTs and analyze related factors Urgency of the topic Multiple researches on application of single-port thoracoscopic surgery in diagnosis and treatment of MTs have been published around the world, initially showing that this method is effective and safe, with few complications, short hospital stay, and high level of aesthetics However, there was no consensus on the recommendation in patient selection for single-port thoracoscopic surgery for MTs, as well as studies with large sample size to evaluate the effectiveness of the method In Vietnam, we started to apply this technique in the treatment of MTs since 2016, and gradually solved some of the major above-mentioned problems related to indications and implementation for surgery Therefore, research on the experience of single-port thoracoscopic surgery in the treatment of MTs at the Department of Thoracic and Vascular Surgery - Bach Mai Hospital will contribute to building the specialty of thoracic surgery in Vietnam Contributions of the thesis This is the first work in Vietnam to systematically study the application of single-port thoracoscopic surgery in the treatment of MTs This research result is the premise for wide application of this surgical technique to other hospitals in the country Thesis layout The thesis includes 137 A4-size pages, divided into chapters, of which: literature review: 02 pages, overview: 38 pages, research method: 28 pages, results: 30 pages, discussion 39 pages, conclusions and recommendations: 03 pages 3 CHAPTER LITERATURE REVIEW 1.1 Diagnosis of mediastinal tumors: 1.1.1 Border, division of mediastinum and mediastinal tumor: The mediastinum is an intrathoracic cavity located between the two lungs, bounded anteriorly by the posterior surface of the sternum and costal cartilages, posteriorly by the anterior surface of the thoracic vertebrae, on both sides by the mediastinal pleura, and the mediastinal pleura behind Below is the diaphragm and above is the base of the neck Mediastinal division: The division method proposed by Thomas W Shields in 1972 is a simple and easy to apply division Accordingly, the mediastinum is divided into compartments: the anterior mediastinum, the mediastinum, and the posterior mediastinum Mediastinal tumors include tumors of various origins, primary or secondary, malignant or benign, arising in the mediastinum 1.1.2 Clinical symptoms of mediastinal tumor: The majority of symptoms are classified into two groups: local symptoms and systemic symptoms Local symptoms are often due to tumor compression or invasion to surrounding structures Systemic symptoms are caused by the release of hormones, antibodies, and cytokines into the bloodstream from the tumor Local symptoms The most common symptoms are respiratory, including wheezing, intermittent shortness of breath, and coughing Coughing up blood or alveolar mucous secretion is a sign of a tumor invading the lung Chest pain is a predictor of invasive malignancy Symptoms due to compression or invasion to mediastinal structures include superior vena cava syndrome, Horner's syndrome, hoarseness Systemic symptoms Some hormone- or antibody-producing mediastinal tumors cause systemic symptoms including specific syndromes, such as Cushing's syndrome caused by adrenal cortical hormone production, often due to neuroendocrine tumors, or hypertension due to phenochromocytomnas tumors… 1.1.3 Imaging study of mediastinal tumors: Chest X-ray: This is the first imaging modality indicated for screening thoracic and mediastinal lesions due to its safety, low cost and convenience The lesion image on the X-ray film is only suggestive and not enough to confirm diagnosis The image of a MT is usually described with the following signs: silhouette sign, hilum overlay sign, cervico – thoracic Sign, mediastinal widening, tracheal and mediastinal compression sign The role of chest X-ray in the diagnosis of tumors/mediastinal function: Currently, chest X-ray is still the most common screening modality for thoracic diseases in general and mediastinal tumors in particular thanks to its availability, low cost and accessibility However, sensitivity is low for smaller tumors and lacks specific features to distinguish the nature of different types of MTs Computed tomography of the chest: Computed tomography with intravenous contrast is the imaging modality of choice for the evaluation and characterization of most mediastinal lesions Information shown on contrast-enhanced thoracic CT scan include (a) the location, size, and structure of the mediastinal lesion; (b) hyper-enhancement and homogenosity; (c) the presence of fatty structures in the lesion, cystic, and calcified components; and (d) signs of compression or invasion to adjacent structures Value of CT scan in the diagnosis of MTs: Currently, contrast-enhanced CT scan is considered the most valuable modality in the diagnosis of MTs, presenting the location, characteristics, and differential diagnosis of the tumors, and its relation to surrounding structures One of the important roles of CT scan is to determine the tumor’s local invasion This is important due to its strong correlation with treatment method and prognosis Other exploration methods: - Chest computed tomography with artificial pneumo-mediastium - Magnetic resonance imaging - Positron emission tomography (PET)-CT 1.1.4 Pathology of mediastinal tumors: The pathophysiology of mediastinal tumors is diverse Data showed that thymoma, neuroma and benign cyst are the most common tumors, accounting for 60% of patients with mediastinal tumors The distribution of histological nature of MTs are different in adults and children: Neuroendocrine tumors, germ cell tumors, bronchial cysts and neuromas are the most common types in children, accounting for 80 % while thymoma, tumors of thyroid origin and lymphomas are more common in adults 1.2 Surgical treatment for mediastinal tumors: 1.2.1 Open surgery: Open surgery is indicated for large mediastinal mass (more than 10 cm) involving surrounding structures such as chest wall, vena cava, pericardium, pulmonary artery, etc There are two approaches: sternotomy and thoracotomy 5 Sternotomy is applied to tumors located in the anterior mediastinum, and lateral thoracotomy is applied to tumors completely displaced to one side of the thorax 1.2.2 Minimally Invasive Thoracic Surgery: Two approaches are currently described: Totally thoracoscopic surgery: Make trocar incisions (approximately 1.5cm) with or without additional accessory (convenient) incisions All manipulations were performed entirely under the guidance of thoracoscopy Video-assisted thoracic surgery (VATS): Make two or more incisions for the trocar and one accessory (convenient) incision All manipulations were performed under the guidance of the thoracoscopy or viewed directly via the convenient incision 1.2.3 Single-port VATS: Single-port thoracoscopic surgery is a surgical method in which the surgeons use only one skin incision of cm or less to perform the operation Methods: - Substernal thoracoscopic surgery: surgeons use a - cm longitudinal incision in the substernal region, creating a tunnel beneath the sternum, opening bilateral pleura to enter the pleural space - Single-port thoracoscopic surgery: surgeons use a 3-4 cm long incision in the 4th – 5th intercostal space on anterior or mid-axillary lines depending on the location of the lesion Thoracoscopic scope and surgical instruments are used in the same way as in the substernal single-incision technique This is a popular technique still applied today In this thesis, we implement this technique Indications for single-port thoracoscopic surgery: Indications for single-port thoracoscopy are not much different from those of conventional thoracoscopy In surgery for MTs, choosing technique depends on: Tumor size, tumor invasion level, cystic or solid structure and surgeons' experience In general, according to many studies, single-port thoracoscopic surgery is indicated in cases of: - Benign tumors diagnosed on CT scan - Tumors that does not invade surrounding structures, especially the brachiocephalic vein of the head - Cystic tumors - Solid tumors < 10cm - Experienced surgeons with conventional thoracoscopic surgery Contraindications and indication for surgical method modification: The contraindications for single-port thoracoscopy are similar to those for conventional thoracoscopy In the early days of conventional thoracoscopy, there existed a long list of contraindications for this approach With increasing experience most of the absolute contraindications in the early days have now turned to relative contraindications However, there is still an absolute contraindication: insufficiently trained surgeons and surgical teams, inadequate equipment Technical principles: - Position of surgeon and assistant: There are two ways of positioning the assistant: (1) the assistant is on the same side as the surgeon, this way allows the assistant better coordination when adjusting the camera and supporting tissue manipulation but limit operative space (2) the assistant standing opposite surgeon: the surgeon has more space for manipulation and the assistant easily stabilizes the camera at the upper edge of the incision but coordination with surgeons will be more difficult - Instrument usage and camera placement: Most surgery today is performed using a long curved suction tube in the left hand and an energy device in the right hand This advancement allows to limit the size of the incision (2–3 cm currently) without affecting surgical time or outcome One of the basic principles of single-port thoracoscopy is to always keep the camera at the upper edge of the incision and the instruments on the lower edge - Principles of selection of instrument and thoracoscope distance: Select operating instruments according to the principle of "one curved - one straight, one short - one long" and adjust the thoracoscope position according to the principle of "the farther the distance - the less the conflict" - Principle of "instrument cross": Surgical instruments should be crossed as much as possible as they are passed through the incision, which minimizes conflict between the thoracoscope body and the instruments - Principle of "traffic lights": Instruments are arranged along the incision line according to the principle of “traffic lights” In which, the scope is always kept at the 'red light' position at the top and the left and right hand tools are placed at the 'yellow light' and 'green light' positions - Location and size of skin incision: Usually, the best incision site is usually at 5th intercostal space between the anterior and mid-axillary lines For lesions on the left side or high above the brachiocephalic vein, it is recommended to approach through 4th intercostal space The position of the incision is slightly offset to the anterior axillary line, making the operation more convenient and helping the patient relieve postoperative pain because the anterior intercostal space is wider The length of the incision can vary from 3–6 cm, depending on surgeons’ preference and experience, tumor size and the thickness of the chest wall Anesthesia in single-port VATS: Single-lung ventilation with a double-lumen endotracheal tube is standard in this technique In some cases (patients unable to tolerate single-lung ventilation or failed to achieve atelectasis or with minor interventions), anesthesia with a single-lumen endotracheal tube with dual-lung ventilation combined with CO2 inflation to create a cavity is an alternative Advantages and disadvantages o Advantages: - Minimal postoperative pain: Due to access to only one intercostal space and not using trocar, single-port thoracoscopic surgery should be more effective in terms of pain relief - Optical advantages: The target approach in single-port thoracoscopy is coaxial approach (the surgeon's eyes and hands work on the same plane), so the hand-eye coordination will be more flexible - Use of a variety of instruments and reduce surgeon’s fatigue: With the 3cm incision, in addition to the camera, or instruments can also be inserted, thus facilitating tissue control and tumor dissection o Disadvantages: - Change the angle of view: surgeons when first perform single-port thoracoscopy need time to be sufficiently proficient, like surgeons with open surgery getting used to laparoscopic surgery - Interference between surgeon and assistant: Due to the surgeon and the camera holder working in a narrow space, the problem of conflict is unavoidable, especially when standing on the same side - Instrument interfence: This is a difficult challenge in single-port thoracoscopy with an incision of only 2,5 – cm, the use of 2-3 instrument in one port may limit the flexibility of the instrument CHAPTER 2: STUDY SUBJECT AND METHOD 2.1 Research subjects Including all patients diagnosed with mediastinal tumor diagnosed and treated with single-port VATS at Thoracic Surgery Department, Bach Mai Hospital from 1/2017 to 12/2020 2.1.1 Inclusion criteria - Patients diagnosed with primary mediastinal tumor - The patient is indicated for single-port thoracoscopic surgery for mediastinal tumor resection - The patient was performed surgery to remove the tumor by single-port thoracoscopy, counting both successful cases and cases requiring another method - Families and patients voluntarily participate in the study - Have complete medical records 2.1.2 Exclusion criteria - Patients with theoretical contraindications to thoracoscopic surgery such as pleural thickening, severe comorbidities or poor respiratory function, inability to tolerate single-lung ventilation 2.2 Research Methods 2.2.1 Study design: A prospective descriptive study 2.2.2 Estimation of the sample size: Convenience sampling 2.2.5 Techniques for single-port thoracoscopic resection for mediastinal tumor at Bach Mai Hospital: based on the procedures performed by world experts in this field, including Atlas of Uniportal Video Assisted Thoracic Surgery by Diego Gonzalez Rivas Indications: + Cystic tumors, or solid tumor less than 10 cm in size + Tumors not invasive to surrounding structures Technical steps of single-port thoracoscopic surgery for treatment of mediastinal tumors o Anesthesia: General anesthesia, double-lumen endotracheal intubation, selective ventilation of one lung (in case of failure to achieve the effect of atelectasis, CO2 inflation can be combined) o Patient position: For tumors in anterior mediastinum 10 The patient lies on the opposite side at an angle of 30 - 45 + For tumors in middle and posterior mediastinum: The patient lies on the contralateral side at an angle of 90 o Position of the surgical team: Position of surgeon and assistant: depending on the mediastinal approach through the right or left intercostal space, the surgeon will stand on the right or left side of the patient, the assistant surgeon will stand on the same side and below the surgeon o Technical steps: - Approach to intercostal space: Depending on the location of tumors, usually approach through 4th, 5th or 6th intercostal space on mid or anterior axillary lines - Evaluation of the tumor: The extent of tumor invasion: if the tumor is not clearly bordered with surrounding structures, poor mobility, especially venous invasion, it is advisable to actively switch to open surgery - Tumor resection: + Thymus tumor: remove the tumor with the thymus gland + Thymus tumor, myasthenia gravis: Extensive thymectomy (thymus and anterior mediastinal fat) + Other tumor cases: Removal of tumor Research variables: - Clinical variables - Diagnostic imaging variables - Intraoperative variables - Postoperative variables - Follow-up variables 3.1.4 Tumor imaging characteristics on chest X-ray: The most common signs of silhouette accounted for 33.8%, mediastinal dilatation 26.2%, 26.2% undetected on chest X-ray 3.1.5 Tumor imaging characteristics on contrast-enhanced CT scan: Location: the anterior mediastinum is the most common location (79%), followed by the posterior mediastinum 12% and the middle mediastinum 9% Tumor size: Mean 5.3 ± 2.2 cm (range 1- 12.5 cm) Contrast enhancement: Most of the tumors did not increase, the density increased slightly or moderately The number of cases increased significantly, accounting for only 10.8% Tumor border and signs of compression of nearby organs: 83.1% of the tumor cases had a clear border with surrounding structures, 78.5% of the cases had no signs of compression to surrounding structures 3.1.6 Correlation between clinical and subclinical symptoms: Clinical symptoms are not related to tumor size or location Tumor size is related to detectability on X-ray, the difference was statistically significant: 7/7 cases with tumor size < cm could not be detected on X-ray, 24/24 cases with tumor size ≥ cm were all detectable on chest Xray There was no difference on X-ray when tumors were in different locations (p > 0.05) The sensitivity of X-ray for anterior mediastinal tumors is the greatest (39/51, 76.5%) 3.2 Results of single-port VATS for mediastinal tumor 3.2.1 Operative results: Ventilation method: Both ventilation methods are used: Single-lung ventilation 54%, dual-lung ventilation 46% Approach: Right approach was more commonly used (61.5%) The most common incision site was in 5th intercostal space on the right side in 24 (36.9%) cases Skin incision length: Average skin incision length: 2.7 ± 0.6 (1.5 -5) cm Intraoperative injury: 58 cases with clear demarcations with surrounding structures, accounting for 89.2% cases of infiltration to adjacent structures: cases invasive to the lung parenchyma, case to brachiocephalic vein, cases of pericardial tumor, case of tumor infiltrating the esophageal wall Surgical methods: Total thoracoscopic surgery in 90.8% of cases 9.2% transferred to videoassisted thoracoscopic surgery or added another skin incision CHAPTER RESULTS 3.1 Clinical and subclinical characteristics of patients with mediastinal tumor treated by single-port VATS 3.1.1 Age Mean: 50.4 ± 14.7 years old Min: 15 years old, Max: 73 years old 3.1.2 Gender: Male: 19, Female: 40 Male/Female Ratio: 19/40 = 0.475 3.1.3 Clinical symptoms: Chest pain is the most common symptom: 46.2% Myasthenia gravis: (12.3%) cases Dry cough 9.2%, hemoptysis 1.5%, shortness of breath 1.5% 20% have no symptoms 11 12 Methods of treatment of intraoperative injuries: In case , a part of the tumor was left behind because the tumor was firmly attached to the phrenic nerve and could not be dissected cases needed additional management: pneumonectomy (2), pericardectomy (2), pneumonectomy + pericardectomy (1), oesophageal wall muscle suture (1), brachiocephalic vein suture (1) cases were managed via thoracoscopy (pulmonary resection, esophageal wall suture, brachiocephalic vein suture) and cases needed change in surgical method: cases required surgical method modification due to large tumor, or infiltration to surrounding structures that were difficult to dissect through thoracoscopy Surgical method modified: cases needed modifying the surgical method (expand the skin incision or add an incision for camera) Cause: large tumors (5/6 cases with tumor size > 6cm), invasion and/or compression to surrounding structures 4/6 cases needed modifying due to accompanying lesions 5/6 cases with postoperative pathological results were teratomas Operative time: The group of completely thoracoscopic surgery patients had an average operating time of 78.7 ± 28.6 minutes, the group of surgical method modification 159.2 ± 64.2 minutes Intraoperative complications: case had major bleeding due to brachiocephalic vein tear (1.5%) 3.2.2 Postoperative results: Time of drainage, length of hospital stay The mean time of pleural drainage was 3.2 ± 1.3 days cases did not have chest tube after surgery case had drainage for days because of concerns of intraoperative esophageal injury The mean postoperative hospital stay was 6.3 ± 3.2 days case was hospitalized for 23 days due to complications of lymphatic leakage Postoperative pain level: VAS score 24 hours after surgery 2.8 ± 0.8 (2-6) points Number of days of analgesic injection 3.2 ± 1.4 (1-6) days 92.3% pain was mild to moderate Post operative complications and sequelae: No serious complications (grade IV, V) cases of level III complications: case of pleural empyema, case of chylous pleural effusion Both cases needed reoperation Diaphragmatic paralysis was found in cases (6.2%) due to the tumors invasive to the nerve that could not be removed Postoperative pathology Thymic tumors was the most common with 35.4% cases, teratomas (21.5%) and thymic cysts (15.4%) There was a case of undeteminable postoperative pathology whether it was thymoma or lymphoma, and lymphoma was confirmed by immunohistochemical staining Masaoka stage I accounted for the major component (73.9%) Stage III was in cases, accounting for 17.4% Thymus tumors type B1 (26.1%) and type B2 (21.7%) were the two most common types Thymic lesions were located in the anterior mediastinum 1/6 cases of neurologic tumor located in the anterior mediastinum were neuroendocrine tumors Most of the teratomas were located in the anterior mediastinum, except for cases located in the posterior mediastinum 3.2.3 Postoperative follow-up results: Evaluation of early results: After month of follow-up, 83% had good results There were no mortality Quality of life: Pain after surgery: 92.8% of cases had no pain weeks after surgery Time to return to work: 73.1% of patients returned to work and normal activities after weeks Mid-term follow-up results: We evaluated the medium-term results with the mean follow-up time of 36.5 ± 20.4 months, the shortest follow-up time was 10 months, the longest followup time was 72 months In August 2022: We had information of 56 patients in which: 87.5% of patients recovered completely, no cases of tumor recurrence were recorded, patient died years after surgery unrelated to surgery (Patient Lo Thi K 67 years old, died from pneumonia/bronchiectasis) 3.2.4 Analyze some related factors: Correlation with intra-operative factors Regarding tumor size: The mean operative time between small and medium size groups had no difference (p > 0.05) The mean operative time between the large and medium size groups was significantly different (p < 0.05) Regarding tumor structure: The difference was not statistically significant, but it seemed that the tumor with mixed structure had longer operative time Regarding to tumor location: There was insignificant difference in operative time for tumors in different location (p > 0.05) The operative time for mediastinal tumor in middle mediastinum was the shortest, in anterior mediastinal tumor was the longest Regarding tumor nature: 13 14 Patients with thymus tumor with myasthenia gravis had the longest operative time 113.1±29.8 (min) Patients with mediastinal teratomas had the highest conversion rate of 3.1% The most common complications of thymic tumors was 10.7% of the cases Regarding the approach: Approaching from the left, the surgery time was longer, but the difference was not statistically significant p > 0.05 Regarding the approaching intercostal space: The surgical time when accessing in different intercostal spaces did not have a statistically significant difference (p > 0.05) In the group of anterior mediastinal tumors (the group that accounted for the largest number in the study, 52 cases): On the right side, when approaching the intercostal space, the average surgical time was short On the left side, when accessing the 4th intercostal space, the mean operative time was shorter Correlation with complication rate: Regarding tumor size: The rate of complications correlated with tumor size (p < 0.05) Complications only occurred in large and medium tumors, in which large tumors accounted for 9/11 (81.8%) Regarding tumor location: Complications 100% occurred in the anterior mediastinum, the difference was statistically significant (p < 0.05) Regarding tumor structure: The complication rate was not statistically significant between tumors with different structures (p > 0.05) However, complications were more common in the solid tumor group, accounting for 8/11 cases (72.7%) Regarding surgical approach: The complication rate was not different when approaching from the right or left side p > 0.05 Post-operative factors: - 100% of the cases requiring surgical method modification had a hospital stay of more than days Compared with total thoracoscopy, there was a statistically significant difference with p < 0.05 - 9/11 cases had complications requiring more than days of hospital stay after surgery - The time of drainage in patient group with long hospital stay was 3.9 ± 1.1 days, compared with 3.0 ± 0.6 in group with short hospital stay In other words, the longer the duration of the drainage was, the longer their hospital stay was - Pain score in the group with a short hospital stay was statistically significantly lower than in the group with long hospital stay (p < 0.05) - Total thoracoscopic surgery had a lower pain score than that of the group with surgical method modification (2.8 vs 4.3), but the difference was not statistically significant (p > 0.05) - The number of days using parenteral analgesia was also shorter in the total thoracoscopic surgery group, the difference was statistically significant (p < 0.05) CHAPTER DISCUSSION 4.1 Clinical and subclinical characteristics of patients with mediastinal tumors operated with single-port VATS 4.1.1 General features Age: Our results were similar to many domestic and international studies by: Ching-Feng Wu, Zhenhuan Tian, Huynh Quang Khanh, Pham Huu Lu Gender The gender-associated problem with mediastinal tumors was not described in literature review In our study, the proportion of women was higher than that of men, similar to many studies 4.1.2 Clinical symptoms In our study 20% were asymptomatic Among symptomatic patients, the most common was chest pain (46.2%) The proportion of symptomatic and asymptomatic patients varied in many studies: In Akshatha Rao Aroor's study, 94.3% had symptoms, Singh et al (94.7%), Dubashi et al (97%) The proportion of asymptomatic cases was higher in the study of Vaziri et al (12%), Adegboye et al (22.9%) and Davis et al (38%) Cohen et al when studying 230 cases of mediastinal tumor found that: 43.9% were asymptomatic, chest pain and respiratory symptoms were the most common (17.4% and 18.7%) In the report of Soner Gürsoy, in 34 cases of cystic mediastinal tumor, 21 patients had symptoms, accounting for 61%, chest pain was the most common symptom (41%), other symptoms included shortness of breath (3 cases), dry cough (1 case), hemoptysis (1 case) Pham Huu Lu et al found that 31.17% were asymptomatic, chest pain was the most common, accounting for 61.04% Ngo Quoc Hung reported 170 cases of mediastinal tumor in which 15.9% was discovered incidentally, cough was the most common symptom 34.1%, and chest pain accounted for 21.8% 4.1.3 Diagnostic imaging signs: Chest X-ray In 65 cases, 48 cases of mediastinal tumor were detected on X-ray, accounting for 73.8% Besides, there were also 26.2% cases undetected on chest 15 16 X-ray The most common sign was the silhouette sign, accounting for 33.8% This is a manifestation of an anterior mediastinal tumor that obscures the heart edges, most commonly seen in thymoma, mediastinal teratoma, or pericardial cyst Mediastinal widening sign (26.2%) was common in anterior superior mediastinal tumors like thymoma In the literature, up to 25% of thymic tumors are not recognized on routine chest radiographs Routine chest radiograph was only an initial screening modality Moreover, on radiographs, it is impossible to evaluate the relation of the tumor with surrounding components accurately Leonid Roshkovan stated that the sensitivity of X-ray in the diagnosis of mediastinal tumors was low, and therefore, small lesions and tumors in the posterior mediastinum were easily misseed (sensitivity was about 6%) Signs on computed tomography Location: In our study, we encountered the highest rate of anterior mediastinal tumors, accounting for 78.5%, followed by 12.3% of posterior mediastinal tumors and 9.2% of mediastinal tumors Our results reinforced the opinion in the literature that anterior mediastinal tumors accounted for the largest proportion of mediastinal tumors in general Tumor content: In 65 cases, the most solid tumors accounted for 55.4%, cystic tumors accounted for 30.8% and mixed tumors accounted for 13.8% This result was similar to other authors’ studies In Soner Gürsoy's study, 76% of cystic tumors were detected in the middle mediastinum, the remaining cases were located in the anterior mediastinum, no cases in the posterior mediastinum Zhenhuan Tian: 108 cases of mediastinal teratoma, 56.5% had mixed structure and all were located in the anterior mediastinum R Duane Davis: 400 cases of mediastinal tumors found that tumors cystic tumors were the most commonly seen in middle mediastinum, in 60/82 cases, accounting for 73.2%, 33% in the posterior mediastinum, and 3.2% in the anterior mediastinum Tumor size: In our study, the average tumor size was 5.3 ± 2.2 cm, the smallest was cm, the largest was 12.5 cm, mostly medium-sized, ranging from to cm in 34 /65 (52.3%) cases and large (larger than cm) in 24/65 (36.9%) cases Our results were similar to other studies in the world and there was no difference with the studies conducted on conventional thoracoscopy With conventional 3-port thoracoscopy: Todd L Demmy reported 48 cases of thoracoscopic surgery for mediastinal tumor, the average tumor size in the study group was 5.2 ± 3.3 cm Yu Fang reported 113 cases of mediastinal tumors operated via thorascoscopy with the average tumor size of 4.6 cm For single-port thoracoscopic surgery: reported by Taiwanese authors, the average tumor size was 4.08 ± 2.05 cm (1.3 – cm); Majed Refai's study 5.1 cm (1.6 - 14 cm) Nanqing Jiang when comparing 3-port thoracoscopy with single-port, the tumor sizes of the two groups were respectively 5.0 cm (3.0 6.0) and 3.9 cm (2.8 - 4.1) Features of invasion and compression: Intraoperative statistics included cases of infiltration into adjacent structures, in which cases to pulmonary parenchyma, case to brachicephalic vein, cases to pericardium and case into the esophagus According to Chung J.W., in the initial selection criteria, only thymus tumors in stage I and stage II were included based on tumor images on chest CT However, the postoperative results were 5/70 cases of tumors in stage III and 2/70 cases of tumors in stage IV In the study of Huynh Quang Khanh, in the inclusion criteria, only patients with tumors non-invasive to surrounding organs were selected based on chest CT scan, but the postoperative results showed cases in stage III (14.1%) ) and stage IV (1.6%) 4.2 Results of treatment of ventricular tumors by single-port VATS 4.2.1 Operative results: Operative time: Our mean operative time was: 86.2 ± 40.2 (minutes), for patients with succesful totally single-port thoracoscopy, mean operative time was 78.7 ± 28.6 (minutes) Compared with conventional thoracoscopic studies, our opertative time was similar (compared with study by Yu Fang, Huynh Quang Khanh) and shorter (compared with study by JW Chung, Pham Huu Lu) With the same surgical method, our operative time was shorter than that of Wu C.F and Refai M and longer than that of Jiang N This author compared single-port thoracoscopy with conventional thoracoscopy in the surgical resection of mediastinal cysts He also showed shorter operative time in the single-port thoracoscopic group, explaining that making more incisions took time and that three small incisions needed more time to stop bleeding and close the incision compared to one single incision Surgical method In our study, 59 (90.8%) cases was performed successful single-port thoracoscopic surgery, cases requiring change in surgical method, accounting for 9.2%, of which cases were transferred to video-assisted thoracoscopic surgery (expanding the thoracoscopic incision, direct visual manipulation combined with using open and thoracoscopy instruments), cases requiring additional trocar (usually using an additional incision lower than the original 17 18 skin incision for camera) In the study, in only case, the tumor could not be resected completely because of its infiltration to the phrenic nerve that risked damage to manipulate The remaining 64 cases had tumors completely removed (98.5% of the tumor) Tran Minh Bao Luan performed thoracoscopic surgery for 55 mediastinal tumors, the rate of complete resection was 44 cases (80%) Author Todd L Demmy performed thoracoscopic surgery for 36 cases, complete tumor removal in 31 cases, leaving a partial cystic tumor in cases Akihiko Kitami, studied 28 cases of thoracoscopy for mediastinal tumors in which the tumor was completely resected in 24 cases (85.7%) 4.2.2 Post-surgery results Postoperative pain: One of the advantages of single-port thoracoscopic surgery is to reduce postoperative pain Theoretically, by accessing only through one intercostal space, without using trocars or widening the incision, it helps reduce pain significantly compared to conventional thoracoscoic surgery and open surgery Single-port thoracoscopic surgery does not use trocar, instead, a wound protector or SILS port helps limit pain and implantation of tumor tissue into the incision during specimen collection Wu found that there was a big difference in postoperative pain scores between the two groups of single-port thoracoscopic and conventional method (first day after surgery 1.45 and 3.69, respectively; hospital discharge day 0.24 and 0.86) Yang et al performed a meta-analysis and found that 24 and 72 hour-postoperative VAS scores in the single-port thoracoscopic group were significantly lower than in the three-port group The main reason was that the single-port approach minimized intercostal nerve damage In addition, the use of a wound protector helped to avoid traction on the incision and incision friction caused by the use of the instrument Length of hospital stay The postoperative hospital stay in our study in the group of totally thoracoscpic surgery was 6.3 ± 3.2 days This was longer than some international studies: Wu: 3.75 ± 1.53 days, Jiang: (4–6) days, Refai: 4.3 days However, compared with conventional thoracosopy, the hospital stay was shorter, reported by Xie A as 7.0 days (2.6 - 14.0), and Jiang as days (5-7) Complications and sequelae: In our study: there was case with intraoperative bleeding due to brachicephalic vein damag, which was managed thoracoscopically After surgery, we recorded cases of complications and cases of sequelae due to intraoperative diaphragmatic nerve damage (16.9%) In cases of complications, there were cases of mild complications at levels I, II with medical treatment, only cases of grade III complications requiring re-surgery, no cases of serious complications or death Demmy performed thoracoscopic surgery in 48 cases of mediastinal tumors without major complications, but there were cases with minor complications, accounting for 14.6% Compared with open surgery, Cohen reported 230 cases of open surgery for mediastinal tumor with 47 cases, complications was seen in 47 (20.4%) cases, of which major complications in 10 (21.3%) cases We also recorded two quite rare complications: case of chylous leakage, case of post operative autoimmune hemolysis Pathology Seen in 65 cases, thymoma was the most common, accounting for 35.4%, followed by mediastinal cysts in 16 cases, accounting for 24.6%, mediastinal teratomas in 14 (21.5%), and case of lymphoma Vaziri's study showed that there were 22 different types of tumors, in which the most common in order of decreasing frequency were: malignant lymphoma (31.5%), Hodgkin's tumor (10.5%), neuroblastoma menorrhagia (10.5%), teratomas (7.5%) and thymic tumors (7.5%) Roviaro performed thoracoscopic surgery for 20 cases in which: thymomas, thymic cysts, thymic hyperplasia in patients with myasthenia gravis, fibrous tumor of mediastinum, pericardaial cysts, teratomas, thoracic lipomas, neuromas and bronchial cyst In 77 laparoscopic cases reported by Pham Huy Lu et al: thymic tumor: 26; dermoid cyst: 15; neuorologic tumor: 17; pericardial cyst: 4; bronchial cysts: 8; other types: In 36 cases of mediastinal tumor reported Tran Trong Kiem, 15 cases of thymoma, cases of neuorologic tumor, cases of lymphoma, cases of serous cyst Thus, thoracopic surgery in general, as well as single-port VATS was not inferior to open surgery In other words, indications for single-port, three-hole or open thoracoscopic surgery does not depend on the anatomical nature Post-operative recovery Re-examination after month showed 83.1% of patients assessed as good: symptom relief, good incision healing, good results on X-ray/ CT scan Evaluation of postoperative persisting pain: 92.8% of the patients no longer had chest pain weeks after surgery The average time of patients returning to work after surgery was 6.7 ± 9.5 weeks (2 - 48 weeks), 73.1% could return to work and normal activities after weeks The rate of patients returning to work after surgery has been mentioned more often in studies of less invasive thoracic surgery to support the argument that this surgical approach is more beneficial to the patient Studies showed that return to work is better with minimally invasive techniques (compared to traditional thoracotomy) Bousamra et al conducted a study (n = 17) to compare 19 20 outcomes among patients with thoracoscopy versus open surgery to remove benign mediastinal tumors On average, the time required to return to work was less in the laparoscopic group (4.3 weeks) than in the open surgery group (7.7 weeks) 4.2.3 Analysis of some relevant factors: Some factors related to the indication: Regarding tumor size: In terms of tumor size, there is no absolute contraindication of thoracoscopy as well as single-port VATS, but it depends a lot on each surgeon’ experience and each individual case However, in our study, large tumors (> 6cm) often caused more difficulty for surgery, longer operative time and higher complication rate Therefore, in our opinion, single-port thoracoscopy is more suitable for small and medium-sized tumors Regarding tumor structure: Our research data also showed that the operative time of cystic tumors is the shortest and also causeed the least complications (1/11 cases) This was consistent with many observations in previous studies Regarding degree of invasion: Majed Refai's experience in single-port VATS made him more concerned about invasiveness than tumor size, and implied that non-invasive tumors are ideal for the single-port thoracoscopic approach even when the tumor was > cm Marco Scarci excluded tumors larger than cm and suspected unknown venous invasion from the single-port approach Yu Fang believed that invasive thymoma was not an absolute contraindication to thoracoscopic surgery Thus, it can be seen that there is disagreement among authors around the world on whether or not thoracoscopic surgery should be indicated in the case of invasive tumors We believe that it is necessary to consider in each specific situation before decision: the nature of the tumor is benign or malignant, which structures are infiltrated, whether the thoracoscopic management will cause dangerous complications for the patient and surgeons’ experience … Regarding tumor location: JW Chung indicated single-port VATS for thymectomy below brachiocephalic veins He found that thoracoscopic imaging was significantly challenging to visualize for tumors located above brachiocephalic veins, and therefore, cause potential danger to perform thoracoscopy Todd L Demmy suggested that small solid tumors located in the posterior mediastinum were ideal for single-port approach Some positions are considered “blind spot” in surgery such as the lung apex, the diaphragmatic angle because it is difficult to access In single-port thoracoscopy, inserting tools into deep space will limit flexibility and cause tool collision, and make manipulation difficult Regarding different tumor nature: - Single-port thoracoscopy for mediastinal teratoma: Our study showed that the operative time of the mediastinal teratoma was the longest (mean 100.7±59.6 minutes) and the percentage of patients who had to modify surgical method in this group was also the highest (7.7%) The surrounding inflammatory nature of teratomas has been reported in many reports Pham L.H, Chang C commented that adhesive inflammation was a challenge in mediastinal teratoma surgery due to the increased risk of bleeding and damage to surrounding organs - Single-port video assisted thoracic surgery for myasthenic thymoma: Statistics on operative time of the patients with myasthenia gravis showed significantly longer result than that of non-myasthenic thymoma group and the operative time was also longer than in some studies performing conventional thoracoscopic surgery for myasthenic thymoma (113.1 ± 29.8 minutes, longer than Le Viet Anh's study 91.80 ± 49.94 minutes conducted with three-port thoracoscopy) In the surgical treatment of myasthenia gravis, in addition to the tumor, the entire thymus gland and mediastinal fat must be removed (extended thymectomy), so the operation time is longer than conventional thymectomy for an adenoma On the other hand, single-port thoracoscopic surgery has limited range of operation in a space of imaginary plane drawn by the instruments when inserted through the incision Therefore, multi-port thoracoscopy allows more flexible access - Single-port video assisted thoracic surgery for mediastinal cystic tumor: In the study group, the surgical time of the cystic tumor was the shortest 65.3±20.1 (minutes) and there was no case to change the surgical method Dario Amore described single-hole laparoscopic surgery for a 45mm pericardial cyst with a surgical time of 35 minutes He considered that single-hole VATS represents the best treatment option in the treatment of cystic fibrosis pericardial cyst Jiang N, through a study of 45 patients, concluded that singlehole laparoscopic surgery is a safe choice for mediastinal cystectomy Some technical factors: Ventilation: The percentage of patients receiving dual lung ventilation was 46.2%, and that of patients receiving single lung ventilation was 53.8% Assessing the correlations of the ventilation method, we found that: The time of surgery and the rate of complications in the two groups had no statistically significant 21 22 difference with p = 0.231 and p = 0.168, respectively Karamollah Toolabi conducted a comparative study of two ventilation methods in thoracic sympathectomy and thymectomy based on operative time, complications, hemodynamic status, SpO2, ETPco2 The study found no difference between the two groups Thus, our study once again contributed to confirm that the intraoperative ventilation method did not affect the surgical results in thoracoscopic mediastinal resection Approach and location of skin incision: We usually approach through 4th, 5th, or 6th intercostal space in the midaxillary line slightly anteriorly (where the chest wall was thinnest and to avoid damage to the long thoracic nerve) In our study, the most common access position was the 5th intercostal space on the right, accounting for 36.9% According to the Taiwanese authors, the appropriate choice of incision site was the 4th and 5th intercostal space: If the lesion was located above the confluence of the brachiocephalic vein to superior vena cava, or when extended thymectomy was required, 4th intercostal space should be approached In other cases, 5th intercostal space was often chosen Gaetano Rocco also suggested that for most thoracic lesions, the intercostal space of choice for access should be in the middle of 4th and 6th intercostal space; for posterior mediastinal lesions, access should be made through an incision between the anterior and mid-scapular lines, in other cases through an incision on the midaxillary line Majed Refai accessed through 5th intercostal space for all cases of single-port thoracoscopic thymectomy Length of skin incision: In our study, the average skin incision size was 2.6 ± 0.5cm (1.5 - cm) for the group successfully performed with single-port thoracoscopy We found that there was no difference in operative time and complication rates with different incision lengths Gaetano Rocco recommended using an incision 2.0-2.5 cm long for singleport thoracoscopy or shorter for diagnostic procedures or sympathectomy In the study of Ching-Feng Wu, the mean incision length in thoracoscopy for mediastinal lesions was 3.41 ± 0.76 cm Majed Refai reported skin incision of 3.5 cm for thymectomy In Marco Scarci's report, a 3-cm skin incision was used Matic Domjan used a 3-cm skin incision to operate a case of a 7cm posterior mediastinal neurologic tumor J Matthew Reinersman reviewed the reports that: an incision less than or equal to 2.5 cm is the standard for single-port VATS However, in practice, there are procedures that required only a 1-cm incision or a larger 3-5 cm incision (pulmonary lobectomy) Several factors related to the results Analyzing the relationship between tumor size and operative time, we found that in the group of large tumors (> cm) the operating time was longer than in the group with small and medium-sized tumors (< cm) Ching-Feng Wu suggested that it was difficult to apply single-port VATS for mediastinal tumors larger than 5.0 cm in diameter, or extensive thymectomy Yu Fang, comparing 113 cases of mediastinal tumors, of which 29 were larger than cm, compared with the group of tumors of smaller size, found that there was no difference in hospital stay and complication rates between the two groups The authors suggested that tumor size should not be considered a contraindication for thoracoscopic surgery Tumor location correlated with operative time We found that the operative time for middle mediastinal tumors was the shortest, while the longest was in the group of tumors in the anterior mediastinum The data also show that 11/11 complications occurred with anterior mediastinal tumors Our study also showed that tumors invasive and compressing surrounding structures make surgery more difficult and require more time to manipulate Majed Refai's experience when selecting patients for single-port VATS he is more concerned with invasiveness than tumor size, he thinks that non-invasive tumors are ideal for the approach of single-port VATS even if the tumor is large size > cm Although the difference was not statistically significant, the group of tumors with mixed structure had a longer surgical time than the other two groups cases of mixed structures having histopathological results as mature teratomas Adhesive inflammation made surgery difficult in these tumors, as noted in many reports, which increased the operative time Some factors related to surgical method modifications: Our surgical method modification rate was 9.2%, including conversion to video-assisted thoracoscopic surgery or making additional skin incisions, no cases had to be converted to open surgery Literature review on conventional thoracoscopy and single-port thoracoscopy showed that the rate of surgical method method in the conventional laparoscopic group was higher than that of single-port Regarding the cause, it was due to large tumor size, tumor infiltrating surrounding structures detected during surgery, pleural adhesions, lung not collapsed during surgery or complications (mainly due to bleeding) 4.2.4 Limitations of single-port video assisted thoracic surgery technique in the treatment of mediastinal tumors: Limiting working space: From the chest wall incision, the camera and the instruments will draw a 23 24 corresponding imaginary plane inside the thorax, the positions outside of this plane are beyond the reach of the instrument, the manipulation would be difficult Limiting vision in case of large tumor: In single-port thoracoscopic technique, the camera is fixed at the upper edge of the incision, so that in the case of large tumors, the shadow of the tumor can obscure the structures behind, resulting in vision limit Large specimens are not intact when taken through the incision: Sometimes the incision is smaller than the size of the specimen, so when removing the specimen, it can rupture or change the cortical-medullary border, making it difficult for pathologists to identify the lesion Of course, this does not affect the operative outcome and is not a big problem for benign lesions due to large tumor size or associated lesions that needed to be manipulated Intraoperative complications rarely occurred (only case), no serious post=operative complications, cases required reoperation, no patients died Single-port thoracoscopic surgery has the inherent advantages of minimally invasive surgery such as short drainage time and short hospital stay On the other hand, single-port thoracoscopic surgery has more advantages in postoperative pain relief (average VAS score assessed at 24 hours after surgery, was 2.8 ± 0.8; 92.8% of cases no longer had pain weeks after surgery), early return to daily work (73.1% of patients returned to work and routines after weeks) 2.2 Some related factors: Surgery is more favorable for cystic and medium-sized tumors (3 - 6cm) non-invasive to the surrounding area However, surgery can still be performed in cases of complicated tumors that require multiple techniques simultaneously (pulmonary resection, pericardectomy, pleurectomy, etc.) single-port video assisted thoracic surgery for extended thymectomy is not a good choice as the operative time is longer than that of the conventional three-port surgery Right approach from the 6th intercostal space should be chosen Left approach should prioritize access through the 4th intercostal space The skin incision length of cm was sufficient to set the instrument for manipulating the lesion, and can be widened when needed CONCLUSION Through the study of 65 cases of mediastinal tumors performed single-port thoracoscopic surgery from 2017 to 2020, we arrived at some conclusions as follows: Clinical and subclinical characteristics of mediastinal tumors performed single-port video assisted thoracic surgery: Patients with mediastinal tumor operated with single-port thoracoscopic surgery often had non-specific clinical symptoms, in which chest pain was the most common, accounting for 46.2% Silhouette sign was the most common sign detected on chest X-ray, accounting for 35.4% 26.2% of cases could not be detected on chest X-ray The mean tumor size measured on CT was 5.3 ± 2.2 (cm), mostly in group of medium and large tumors (tumors size > 3cm accounting for 89.2%) A large proportion in our study group were tumors in the anterior mediastinum (80%) and tumors with solid components (54.5%), irregular tumor margins found in 16.9% of cases Tumor compression to adjacent organs was found in 21.5% of cases Results of single-port video assisted thoracic surgery for mediastinal tumor and some related factors: 2.1 Operaive results: Single-port video assisted thoracic surgery in the treatment of mediastinal tumors is safe and highly feasible, with a success rate of 90.7% The technique can be applied to both single-lung and dual-lung ventilation The mean operative time was 86.2 ± 40.2 (min), shorter than three-port technique in some studies There were cases where surgery had to be modified LIST OF RELEVANT PUBLISHED ARTICLES Article name Clinical and paraclinical characteristics of patients with mediastinal tumor treated by single-port video assisted thoracic surgery Result of anterior mediastinal tumoral treatment by single-port video assisted thoracic surgery Uniportal video-assisted thoracoscopic mediastinal tumors resectipon: the glove-port with carbon dioxide insufflation Bilateral single-port videoassisted thoracoscopy for extended thymectomy in the treatment of myasthenia gravis Single-port VATS for mediastinal tumor resection Journal Vietnam Medical journal Vietnam journal of Surgery and endolaparosur gery 108 Journal of Clinical Medical and Pharmaceutical Science Vietnam journal of Surgery and endolaparosur gery Vietnam journal of Surgery and endolaparosur gery Authors Ngo Gia Khanh, Nguyen Huu Uoc, Tran Trong Kiem Ngo Gia Khanh, Nguyen Huu Uoc, Tran Trong Kiem Ngo Gia Khanh, Nguyen Huu Uoc, Tran Trong Kiem Ngo Gia Khanh, Nguyen Huu Uoc, Tran Trong Kiem Ngo Gia Khanh, Nguyen Huu Uoc, Chapter Page Vol 510, No 2, Jan, 2022, p 183 - 186 Vol 12, No 1, 2022, p 34 - 43 Vol 16, No 5, 2021, p 118 - 123 Vol 8, No 2, 2018, p 12 – 18 Vol 6, No 1, 2016, p 11 – 16