1 Lithuanian University of Health Sciences
MEDICAL ACADEMY FACULTY OF MEDICINE
Yaniv Cojocaru
The Surgical Treatment of Non-Malignant Subglottic Stenosis Department of Cardiac, Thoracic and Vascular Surgery
Scientific supervisor: Prof. Romaldas Rubikas
2 Table of Contents
1. SUMMARY ... 4
2. CONFLICT OF INTERSET ... 6
3. ACKNOLEDGEMNT ... 7
4. ETHICS COMMITTEE STUDY PERMISSION ... 8
5. INTRODUCTION ... 9
6. AIMS AND OBJECTIVES ... 10
7. LITRETURE REVIEW ... 11
7.1 . General information concerning the anatomy and pathology related to non-malignant Subglottic stenosis ... 11
7.1.1. Larynx ... 11
7.1.2. Trachea ... 11
7.1.3. Stenosis ... 11
7.2. Etiology of non-malignant Subglottic stenosis ... 12
7.2.1. Idiopathic Subglottic stenosis ... 12
7.2.2. Intubation-induced Subglottic stenosis ... 12
7.2.3. Tracheostomy-induced Subglottic stenosis ... 12
7.2.4. Tracheostomy and intubation compression... 13
7.2.5. Blunt chest trauma ... 13
7.2.6. Traumatic brain injury ... 13
7.3. Pathogenesis ... 14 7.4. Diagnostic procedures ... 14 7.4.1. Flexible Bronchoscopy ... 14 7.4.2. Virtual “Bronchoscopy” ... 15 7.4.3. Computed tomography ... 15 7.4.4. Staging ... 16 7.5. General anesthesia ... 17
7.6. Traditional methods of surgical treatment: ... 17
7.7. Complications ... 18
7.7.1. Wound infection ... 18
3
7.7.3. Nosocomial infection ... 18
7.7.4. Death ... 18
8. RESEARCH METADOLOGY AND METHODS ... 20
8.1. Patient selection and amount ... 20
4 1. SUMMARY
Master thesis by Yaniv Cojocaru
Title – The surgical treatment of non-malignant Subglottic Stenosis.
The aim of the theses- Analyze the results of the surgical treatment of non-malignant Subglottic Stenosis in thoracic surgery department of “Kauno Klinikos” university hospital.
Objectives of the study- 1. To analyze the surgical treatment approaches used in case of
non-malignant Subglottic stenosis in thoracic surgery department of "Kauno Klinikos" university hospital. 2. To evaluate early postoperative Bronchoscopy results as prognostic factor for post-operative clinical course compared to years 1992-2011 results in thoracic surgery department of "Kauno Klinikos" university hospital. 3. To integrate and evaluate the outcomes of non-malignant Subglottic stenosis surgeries in the years 1992-2018 in thoracic surgery department of "Kauno Klinikos" university hospital.
Methodology-This study was done retrospectively by integration of eighty-three patient’s cases which were diagnosed and operated for Subglottic stenosis in "Kauno Klinikos" university hospital in the years 1992-2018. During this period patients underwent early postoperative bronchoscopy to assess the risk for possible complications. A scale ranging from 0-10 points proposed by assessing the sagittal and transversal diameter of lower part of the larynx, Subglottis. An analyze of eleven cases during the years 2011-2018 was required to be done and which was integrated with past data analyzed for the years 1992-2011 to generate final results for the years 1992-2011.
Results- The results of current analysis regarding the years 2011-2018 were integrated to the final results of the mentioned analysis above. The results of this step showed that in total during the years 1992-2018, eighty-three patients underwent surgical correction for non-malignant Subglottic stenosis in the department of thoracic surgery in "Kauno Klinikos" university hospital.
Seventy-six patients had early Bronchoscopy scale above 7, seventy-four didn't required surgical re-intervention while two patients were required to undergo surgical re-re-intervention. Seven patient had early Bronchoscopy scale lower than 7 and required to undergo surgical re-intervention.
5 ABREVIATIONS
Cm – Centimeters
CT- Computer Tomography Mm- Millimeters
6 2. CONFLICT OF INTERSET
7 3. ACKNOLEDGEMNT
9 5. INTRODUCTION
Tracheal stenosis is an uncommon disease that has numerous possible causes. Etiologies such as endotracheal intubation due to brain trauma or airway occlusion during trauma event such as car accident, blunt chest trauma, hemorrhagic shock respiratory failure or idiopathic. [1, 2, 12, 18]
Subglottic (lower part of the larynx and trachea) stenosis most often has deceptive onset. Early symptoms and signs manifested during the disease may cause confusion with a variety of other disorders or diseases. Shortness of breath on exertion, that may progress to dyspnea at rest, a harsh and loud cough, recurrent pneumonitis, wheezing, stridor, and cyanosis may all manifested as clinical presentation. Many of those symptoms, especially dyspnea on exertion and wheezing, can be easily regarded as other respiratory diseases symptoms such as chronic bronchitis and asthma, leading to the importance of taking full anamnesis of the patient and to try gather as much as possible
information.[30]
Nowadays, the diagnosis of Subglottic stenosis is done by procedures or methods that all patients are needed to do in order to decide the most correct treatment for them. The methods that are being used for examination are flexible Bronchoscopy, neck and chest Computer Tomography scan. When dealing with patient that are intubated by tracheostomy tubes in, airways are assessed by using flexible Bronchoscopy which is inserted through the nose or mouth and if needed the access point of the tracheostomy tube by recording of the distance from the vocal cords up to the stenotic area, internal diameter of the stenotic segment, and the planned to resection segment length.
After establish the final diagnosis of non-malignant Subglottic stenosis by use of flexible Bronchoscopy and chest Computer Tomography scan finding the patient are taken to the OR. During Surgery two techniques are available to be used: cricotracheal resection and thyrotracheal anastomosis as seen in Figure 1 or tracheal resection and/or Tracheotracheal anastomosis as seen in Figure 1A. [1] Possible complications that are corresponding with hospital stay and surgical intervention are wounds infection, recurrent nerve palsy, unsatisfactory early condition of the surgery site and the anastomosis done during the operation, nosocomial pneumonia and intraoperative death.
Fig. 1: Cricotracheal resection and thyrotracheal anastomosis from anterior and lateral views
10 6. AIMS AND OBJECTIVES
Aim: To analyze the results of the surgical treatment of non-malignant Subglottic stenosis in thoracic surgery department of "Kauno Klinikos" university hospital.
Objectives:
1. To analyze the surgical treatment approaches used in case of non-malignant Subglottic stenosis in thoracic surgery department of "Kauno Klinikos" university hospital.
2. To evaluate early postoperative Bronchoscopy results as prognostic factor for post-operative clinical course compared to years 1992-2011 results in thoracic surgery department of "Kauno Klinikos" university hospital.
11 7. LITRETURE REVIEW
Preoperative period
7.1. General information concerning the anatomy and pathology related to non-malignant Subglottic stenosis
7.1.1. Larynx
The larynx is a short tube which is located above the trachea. It composed from a wall of hyaline cartilage, elastic cartilage, muscles and other soft tissues. It plays major rule in normal
individual’s functions of breathing, swelling food and speaking. The larynx is anatomically divided to three constitutional components: upper part(supraglottis), middle part (glottis, vocal cords) and lower part of trachea which is also known as Subglottis.
The supraglottis is the part which situated above the vocal cords, at the glottis the vocal cords located there and the subglottis the part right below the glottis part. Illustration of the anatomy of the neck can be seen in figure 2.
Fig. 2. Larynx anatomy
7.1.2. Trachea
The windpipe is approximately 10-12 cm long tube which is lined with mucosa that contains watery mucus producing glands. It’s composed from incomplete cartilage rings in inverted U-shape (18-22 cartilaginous rings) which line roof of the air way while the floor is composed from muscle’s band and other soft tissues. During the process of respiration while breathe the trachea will expand and contract while during swallowing the muscle will relax to allow free passage of food.
7.1.3. Stenosis
12 7.2. Etiology of non-malignant Subglottic stenosis
7.2.1. Idiopathic Subglottic stenosis
Idiopathic Subglottic stenosis is diagnosed when the doctors can’t establish specific cause for the inflammation and scarring processes of the involved segment. Wegener’s disease is the
autoimmune disease most associated with stenosis which is characterized by the presence of necrosing granulomatous inflammation in the upper respiratory tract and small or medium vessel vasculitis. [29] 7.2.2. Intubation-induced Subglottic stenosis
Direct laryngoscopy and Endotracheal Intubation are procedures that require wide variety of specialties. Nowadays, tracheal intubation is indicated in acute patients presenting with acute RF, hypoventilation and hypoxia.
Before surgery and according the operation team, direct laryngoscopy and Endotracheal Intubation might be needed to be place in order to provide air supply to patients under general
anesthesia, patients having operation next to the airway or unconscious patients that require protection of the airway.
If the supraglottic or glottic parts of the larynx have pathologies this will cause the intubation to be contraindicated and won’t be performed, therefore tracheostomy will be needed. [1, 2, 12, 18] 7.2.3. Tracheostomy-induced Subglottic stenosis
13 7.2.4. Tracheostomy and intubation compression
7.2.5. Blunt chest trauma
Blunt chest trauma is result from any direct blow to the face or the neck as well as a crush injury to the chest. Blunt chest trauma is problematic due to the fact that the force applied on the patient during the accident can cause wide variety of damage to the chest’s organs. Those traumas to the internal organs cause ventilation process to be compromised and eventually tracheostomy or intubation might be needed. [1, 8]
7.2.6. Traumatic brain injury
Brain insult is one of the main manifestations of traumatic brain injury caused by blunt force injury. The insult is acute situation that can result in the cognitive and mental function. Patients having insult might be unconsciousness which associated with impaired breathing function forcing the
medical staff to place intubation or tracheostomy.
The physical mechanisms of brain injury can be classified to the following categories: Impact, Impulsive and Static .[1, 2]
Table 1: compression between Tracheostomy and intubation procedures adapted from UP-TO-DATE
Tracheostomy Intubation
Advantages • Ease of replacement (once tract has formed) • Speech, mobility, and swallowing enhanced • Patient can be nursed outside of Intensive
Care Unit
• Ease of suctioning • Patient comfort
• Rapid insertion by skilled consultant in most settings • Lack of need for surgical
procedure (risk, expense) • Lack of stoma complications Disadvantages • Stomal complications
• Possible contribution to ultimate laryngeal injury
• Possible increase in pulmonary infections • Access to mediastinum by infectious agents
after local surgery
• High mortality for inadvertent decannulation before tract formation
• Laryngeal complications
• Replacement requires skill at all times
• Generally, requires Intense Care Unit level supervision
14 7.3. Pathogenesis
Fig. 2: pathogenesis of acquired subglottic stenosis [30]
7.4. Diagnostic procedures
7.4.1. Flexible Bronchoscopy
Flexible Bronchoscopy is a flexible scope compare to the rigid Bronchoscopy which is used under sedation of the patient to allow access to the lower segments of the airways. The flexible Bronchoscopy can be inserted from the nose or the mouth, however if tracheostomy is present it will function as the entrance site. In case of tracheal stenoses, it allows to record the vocal cords until the lesion, assess the internal diameter and its length of the stenotic segment and to decide length of the resection. [1, 8, 12]
Fig.4: flexible Bronchoscopy showing stenosis
Stenosis
Healing initiates with fibroblast proilferation ,scar formation and contracture Irritator removal
Ulceration and granulation tissue formation Repeated irritation
15 7.4.2. Virtual “Bronchoscopy”
A form of non-invasive method of investigation done virtually to demonstrate the trachea and bronchus without using flexible Bronchoscopy. By using imaging modality that allows demonstrating the airways in 3D pattern. Main disadvantage of this procedure is the inability to produce samples from the lesion. Figure 4 shows concentric narrowing of the airway in proximal aspect and distal aspect. [1, 8, 12]
Fig. 5: Virtual "Bronchoscopy"
7.4.3. Computed tomography
Computer Tomography scan is informative radiological modality which assists in assessment of the stenotic segment. Eccentric or concentric soft tissue thickening in internal aspect of tracheal cartilage is the main evidence to the stenosis. It’s recommended to record vocal cords up to the lesion, the internal diameter and the length of the stenotic segment and the length of planned resection
segment.
As seen in figure 3, numerous stenotic segments are well observed while rest of trachea maintain normal diameter. [1, 15]
Fig.6: CT scan demonstrating stenosis in various locations
16 7.4.4. Staging
The staging of the Subglottic lesion is done according the Myer-Cotton grading system. The system takes under consideration the tube size inserted, age of the patient and the pressure of the leak. The grades are: [2,7]
Grade I - Less than 50% laryngeal lumen obstruction Grade II - 50-70% obstruction
Grade III - 71-99% obstruction with an identifiable lumen present Grade IV - Complete obstruction; no lumen present
17 Intraoperative period
7.5. General anesthesia
Anesthesia embodies control of the main concerns relate to the surgery and patient’s experience: consciousness, pain and movement. General anesthesia results in unconsciousness and amnesia, analgesia and muscle relaxation to allow the surgeon better setting of operation without interruptions from the patient which may cause intraoperative complications. When elective surgery is first planned, a complete anamnesis needs to be done by the anesthesiologist to provide information regarding patient’s comorbidity that may require early preoperative review and/or intervention. Based on these findings, the anesthesiologist may find that the patient is not in optimal medical condition to undergo elective surgery. These findings and opinions are then discussed with the patient’s physician, and the surgery may be delayed or cancelled until the patient’s medical conditions further tested and optimized or stabilized. There are two possible ways of anesthesia induction: the intravenous route is the most common method of induction, allowing delivery of a bolus of drug to the brain, which results in rapid loss of consciousness.
Inhalation induction of anesthesia is slower compare to intravenous but it allows needle-free anesthesia induction which is important in case of children. During the operation the anesthesiologist will monitor vital signs and the effectiveness of the anesthesia. Emergence from anesthesia, although usually without events, can be associated with major morbidity. In the immediate postoperative period, patients are at risk from respiratory and cardiovascular complications. [24]
7.6. Traditional methods of surgical treatment:
After general anesthesia was introduced the surgical team by using mediastinoscopy can look into mediastinum. The use of video-based surgical technique allows safe dissection of the trachea’s cartilaginous wall. When dissecting the pretracheal fascia which is located below thyroid gland, surgeons might be required to be caution with the inferior thyroid vein to avoid intra-operative bleeding by produce vein ligation. Proper insertion of the scope is confirmed by visualizing the tracheal rings and stenotic segment. Surgeon will perform anterior and lateral dissection of the lower part of the larynx and the circumferential tracheal dissection while sparing the inf. laryngeal nerves extended over the scar.
18 In cases of subglottic-tracheal stenosis, the anterior and lateral parts of the cricoid cartilage were resected and removed while leaving the posterior portion intact. In all cases it’s required to completely remove all the tracheal lesion.
Any bleeding requires electrocoagulation to stop it. Possible complications of the surgery are recurrent nerve palsy which can be prevented by taking care at the both tracheobronchial angles, unsatisfactory early condition of the surgery site and the anastomosis done during the operation, nosocomial pneumonia and intraoperative death. [1, 2, 14, 16, 18, 19, 20]
7.7. Complications
7.7.1. Wound infection
Wound infection is a possible complication during the postoperative period. In order to prevent this complication, there are few steps that are needed to be taken, first is proper closer and bandaging with aseptic agents of the wound induced during the operation by the surgeon. Second, prophylaxis antibiotics such as 2nd generation cephalosporin agent for period of 7 days and by
shortening hospital stay of the patient after the operation together with proper education about wound care. [1, 21]
7.7.2. Recurrent nerve palsy
According “Barr's the human nervous system” the recurrent nerve is a branch of cranial nerve X, Vagus. It originates from between the pyramid and the inferior cerebellar peduncle. Damage to the recurrent nerve will result in hoarseness; change in voice quality and bovine cough. The surgeon most pay special attention during any neck operation in order not to damage the nerve especial by taking care at the both tracheobronchial angle. [1.22, 25]
7.7.3. Nosocomial infection
Hospitals are the habitat for many micro-organisms that are associated with nosocomial infection. According the “Centers for Disease control and Prevention” the most common bacterial agents that cause nosocomial infections are Staphylococcus Aureus, Pseudomonas Aeruginosa and Escherichia Coli. In order to prevent those infections each hospital most have asepsis policy and prevention plans. Other possible ways to prevent this complication is to use prophylaxis antibiotics regime and shortening hospital stay. [1, 17]
7.7.4. Death
19 assessment for death according to the patient general status, age, comorbidities, and the surgical
procedure. It’s important to mention that any surgery has its own risk and possible complications.
Figure 7 demonstrates the complete approach of management of a patient presenting with cardinal signs of Subglottic stenosis. This research point of interest is the postoperative period which includes the early postoperative Bronchoscopy and the follow-up.
Figure 7: Final approach of management of patient presenting with signs of Subglottic stenosis Discharge
and Follow up
Early Post-operative Bronchoscopy
Laryngotracheal stenosis surgical repair
Diagnostic Aprroach : 1. Bronochoscopy(virtual or flexible)
2. Computed Tomography scan(optianl or for surgical planning) 3. Grading
20 8. RESEARCH METADOLOGY AND METHODS
8.1. Patient selection and amount
Eleven patients, who diagnoses and operated for non-malignant Subglottic stenosis between the years 2011-2015 in the department of thoracic surgery in "Kauno Klinikos" university hospital were selected for a retrospective study evaluating the outcome and prognostic factor. Patient were divided to 2 groups, those who had no need for future intervention and those who required re-intervention. Integration with the results of similar study with 72 cases done in 2012 which checked retrospectively the results of surgeries done between 1992-2011.
Each patient was evaluated by type of anastomosis done during operation, length of resected segment during the operation, postoperative Bronchoscopy scale to assess outcome, re-intervention after detecting pathological changes in the Bronchoscopy and repeated Bronchoscopy was indicated only by requirement.
8.2. Outcomes variables
The outcome of surgical treatment of non-malignant Subglottic stenosis is assessed by the use of scale measured during early postoperative Bronchoscopy done in the 5th-9th day after the surgery. The scale ranges from zero which is no change in the luminal diameter of trachea while result of 10 is complete correction of the trachea.
8.3. Statistical analysis
The statistical analysis was performed using IBM “SPSS” (Statistical Package for the Social Science), version 20.0 and Microsoft Excel. The in-dependable t-test was used for testing the
21 9. RESULTS
Eleven patients were operated for non-malignant Subglottic stenosis between the years 2011-2018 in the department of thoracic surgery in "Kauno Klinikos" university hospital were chosen for this analysis. Patients were divided to two separate groups, those who had no need of repeated Bronchoscopy and re-intervention and those we did required future evaluation. By conventional criteria this difference is considered statistically significant (p = 0.009). See table 3.
Table 3: Groups of analysis
Amount Percentage Significance level (p≤0.05)
Required repeated Bronchoscopy & re-intervention 2 18.2% p = 0.009
Not required repeated Bronchoscopy & re-intervention
9 81.8% p = 0.009
In order to assess the success rate of the surgical corrections done in the department of thoracic surgery in "Kauno Klinikos" university hospital during the years 2011-2018, the early anastomosis condition was evaluated by preforming early postoperative Bronchoscopy at the 5th to 7th day post operation. The mean of scored scales was calculated from eleven cases. The result calculated was 8.5 points. See table 4.
In the department of thoracic surgery in "Kauno Klinikos" university hospital two approaches are used by the surgeons to correct the stenosis. The first approach is Cricotracheal resection and thyrotracheal anastomosis which was done twice only during the years 2011-2018 the other one, Tracheal resection and Tracheotracheal anastomosis was done in the rest of nine cases, See table 5.
The mean score of the patients who didn't required repeated Bronchoscopy and/or re-intervention was 8.83 while the mean score of the patient who didn’t required was 6.9.
Both patients that were required to have re-intervention in the period after the surgery had granuloma formation which was the cause in lower score in the scale. Due to the low number of
Table 4: Mean of scale of early postoperative Bronchoscopy in the period of 2011-2018 Mean
scale
Number of patients
Std. Deviation
Early postoperative Bronchoscopy scale 8.5000 11 1.00000
Table 5: distribution of cases according the surgical approach used
Type of anastomosis done during surgery Number of
patients
Cricotracheal resection and thyrotracheal anastomosis 2
22 patients with non-malignant Subglottic stenosis significance level can't be checked(p=0.227). See table 6.
Table 6: Early postoperative Bronchoscopy scale as relation to repeated Bronchoscopy and/or re-intervention
Postoperative Bronchoscopy and/or re-intervention Number of patients Mean scale
Early postoperative Bronchoscopy scale
No repeated Bronchoscopy and/or
re-intervention 9 8.8333
Repeated Bronchoscopy and/or
re-intervention 2 6.9
Each patient had different length of resected stenotic segment. A Compression to find association of repeated Bronchoscopy and/or re-intervention. The results showed that those two
patients who required repeated Bronchoscopy and/or re-intervention had mean length of resection 7.85 centimeters while on the other hand, the nine patients who didn't had repeated Bronchoscopy and/or re-intervention had mean length of resection 2.83 centimeters. See table 7.
In previous study done in 2012 and checked early post-operative Bronchoscopy of 72 cases showed that 65 patients had early Bronchoscopy scale in range of 7 to 10 didn't needed a postoperative Bronchoscopy and/or re-intervention while 7 patients were needed postoperative Bronchoscopy and/or re-intervention. One of the patients that were needed surgical re-intervention had early Bronchoscopy scale above 7 and the rest were less than 6.9. See Graph 1.
Table 7: Resection length as relation to repeated Bronchoscopy and/or re-intervention Postoperative Bronchoscopy and/or re-intervention Number
of patients
Mean length(cm)
Length of resected segment(cm)
No repeated Bronchoscopy and/or re-intervention
2 7.8500
23 The results of current analysis regarding the years 2011-2018 were integrated to the final results of the mentioned analysis above. The results of this step showed that in total during the years 1992-2018, eighty-three patients underwent surgical correction for non-malignant Subglottic stenosis in the department of thoracic surgery in "Kauno Klinikos" university hospital.
Seventy-six patients had early Bronchoscopy scale above 7, seventy-four didn't required surgical re-intervention while two patients were required to undergo surgical re-intervention. Seven patient had early Bronchoscopy scale lower than 7 and required to undergo surgical re- intervention. See graph 2.
Graph 2: distribution of 83 patients underwent surgery for non-malignant Subglottis stenosis in the years between 1992-2018
24 10. DISCUSSION
The aim of the research was to assess and evaluate the surgical correction of non-malignant Subglottic stenosis with data gathered in the period between 1992-2018, in the department of thoracic surgery in "Kauno Klinikos" university hospital.
Rubikas, Romaldas et al, 2014, by using Bronchoscopy, the early internal condition of the
anastomosis was assessed as excellent (10 points) in 62 (84.9 %), satisfactory (9–8 points) in 3 (4.1 %), and unsatisfactory (7–5 points) in 8 (11.0 %) out of 73 patients. The statistical analysis revealed that assessment less that 6.9 points predicts restenosis and requirement for future requirement for Bronchoscopy and/or re-intervention. The research assessed early internal conditions of the
anastomosis of 72 cases. It showed that 65 patients had early Bronchoscopy scale in range of 7 to 10 didn't needed a repeated Bronchoscopy and/or re-intervention while 7 patients were needed
postoperative Bronchoscopy and/or re-intervention [1]
During the years between 2011-2018, eleven patients were diagnosed and operated for non- malignant Subglottic stenosis. There are two approaches for this correction, cricothyroid anastomosis which was performed on 2 patients while the second approach Tracheotracheal anastomosis was performed on the rest 9 patients. The mean of the early postoperative Bronchoscopy scale in the period of 2011-2018 was 8.83.
In order to overcome the difficulty that arose due to the low number of patients treated for non-malignant Subglottis stenosis in the years 2011-2018, data gathered in 2012 for the years of 1992-2011 were joined together to achieve and reach conclusion for eighty-three patients and not only eleven.
After integrating the two periods of years, a graph was generated and demonstrated that all seventy-four patients who didn't required postoperative surgical re-intervention had postoperative Bronchoscopy scale ranging from 7 to 10 points. On the other hand, nine patients out of eighty-three indeed required repeated Bronchoscopy and/or re-intervention and they had early postoperative Bronchoscopy scale was less than 6.9 points
25 11. CONCLUSIONS
1. Early postoperative Bronchoscopy is necessary to assess the early anastomosis condition in order to predict risk for postoperative Bronchoscopy and/or re-intervention will be needed.
2. The early postoperative Bronchoscopy is recommended to be done 5-7 days after surgery.
3. The first postoperative evaluation of Bronchoscopy by a score of less than 7 can reliably predict the risk for repeated surgical intervention.
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