4 | Discussion
Deep neck spaces are multiple spaces including the parapharyngeal space, the posterior pharyngeal space, the sublingual space and the lower jaw space(4). DNSI is often secondary to infection of tonsil, teeth, upper respiratory tract or deep neck surgery(5). If the infection can not be controlled in time, it can spread to each other through the deep neck spaces, even up to the skull base and down to the mediastinum. It can also cause other parts of the abscess, and even systemic symptoms. DNSI also lead to upper respiratory tract obstruction, and eventually cause serious consequences and even death.
Our study showed that the most frequently involved deep neck spaces were parapharyngeal space (27 cases) and submandibular space (11 cases), which were consistent with the results of Huang et al (6). Some studies also supported that parapharyngeal space and submandibular space were the most frequently involved deep neck spaces(5,7,8).
In case 1, the patient was diagnosed as necrotizing myofascitis of the neck. In general, there was not much pus during the operation. Once the drainage cavity was exposed, the pus would increase sharply, even up to 150 ml of drainage per day. In view of this situation, we used the pyogenic cavity aerobic therapy, which was to pass the oxygen tube to the operation cavity, and the oxygen flow is initially adjusted to 3L/min. After the first use, the pus exudation was reduced to about 10-15 ml the next day, and then according to the amount of exudation in the operation cavity, the oxygen flow was gradually reduced until the removal. During this period, we observed that if the oxygen flow rate was adjusted to more than 4L/min, the operation cavity would be too dry. It would induce the gauze adhere to the deep neck tissue, which was not easy to separate. This kind of situation was not conducive to the growth of granulation tissue and wound healing. Secondly, during the period of aerobic treatment, the neck bandage should be loose, so as to facilitate the outflow of oxygen, to prevent the infection from spreading to the surrounding spaces due to excessive air pressure. The oxygen flow tube should not be plugged into the dead cavity, avoiding serious consequences. When the drainage fluid is clear or reduced to less than 10 ml, the drainage should be removed during using negative pressure drainage with suture of operation cavity. If the pus cavity is connected with the gas incision stoma, it needs to be blocked by suture (Figure. 3F, shown by the yellow arrow), so as to avoid the sputum drainage into the infection cavity during negative pressure drainage. For this kind of patients, the previous treatment methods are mostly incision and drainage of pus, dressing change 1 to 2 times a day, until the pus disappeared or granulation tissue filled the operation cavity, suture the incision, or even change dressing until the incision healed. It often takes half a month to a few months. This patient underwent postoperative dressing change for only 4 days, and the volume and situation of drainage fluid were observed daily after negative pressure drainage. It greatly reduces the psychological and physical trauma of patients and the workload of clinicians.
Patients should be paid close attention to the general situation, especially blood glucose and blood pressure. Without good blood glucose control, ketoacidosis, hypertonic syndrome, lactic acidosis or hypoglycemia may occur, which is not conducive to the follow-up treatment. In this study, 25 cases were accompanied with type 2 diabetes, accounting for 49.0%. Most of them had large fluctuation of blood glucose level with poor control. After admission, we should actively contact doctors of the Department of Endocrinology for consultation, adjust the application of hypoglycemic drugs, especially for patients with oral feeding difficulties and needing nasal feeding nutrition. We chose insulin to control blood glucose as much as possible. According to the results of blood glucose monitoring, the type and dosage of insulin should be adjusted in time. Nutritional support is very important for patients with DNSI. Because the lesions are located in the neck and oropharynx, many patients have oral feeding difficulties. In this regard, we can indwelling gastric tube for nasal feeding nutrition and guide the family members of patients with nasal feeding knowledge, also can use nutrition liquid 500ml-1500ml every day. During this period, blood routine and biochemical indexes should be reexamined daily or every other day to understand the infection index, electrolyte status and nutritional status of patients. For patients with poor general conditions, especially those with poor cardiopulmonary function, they need to be transferred to the intensive care department for further treatment.
The most effective treatment for DNSI is incision and antibiotic therapy (9-11). Flushing and dressing change, intermittent suture of wound and the negative pressure drainage of pus cavity were used. For first-line clinical doctors, more doctors still use traditional flushing and dressing change treatment. It was reported that the drainage tube placed in the pus cavity was used to treat the infections of the deep neck space, and had obtained good efficacy and cosmetology effect(12,13).
This method is a good way for small single abscess. We consider that when the abscess in the deep neck spaces has formed in a large area, incision and drainage should be carried out as early as possible, especially for the multiple lacunar abscess. During the operation, all the septa should be separated as far as possible without dead space left, and the necrotic tissue should be completely removed while the important nerves and blood vessels are preserved.
If the abscess has not yet formed or the scope is small, the patients can be followed up by CT examination or color Doppler ultrasound examination according to the general situation. It was reported that combined with thorough clinical examination, the accuracy of CT imaging in differentiating drainable abscess and cellulitis can reach 89%(14-15). Mark et al reported that the diameter of abscess > 2.5 cm on imaging examination was an important predictor of surgical intervention [15]. This indiator has important value for clinical treatment. For patients who choose conservative treatment, if the scope of abscess is not reduced or further expanded within 48 hours, incision and drainage should be carried out as soon as possible. In any case, once the diagnosis is made, we should first closely observe the patient’s breathing condition, and tracheotomy should be performed as soon as possible if dyspnea occurs. Local anesthesia is recommended with the help of an anesthesiologist because the patient may have airway distortion, tissue stiffness, and limited mouth opening. Because intubate may make the damaged airway worse, so we should not use laryngoscope tracheal intubation(16). Case 2 diagnosed as deep neck space infection only underwent tracheotomy under local anesthesia. After active anti-inflammatory treatment and close follow-up CT examination, she was found that the scope of inflammation did not further expand, and gradually reduced. Finally, after the inflammation disappeared, the tracheotomy cannula was removed. And the patient finally recovered. The treatment method avoids the pain of debridement and dressing change.