What Is the Parapharyngeal Space?

Parapharyngeal space tumors refer to tumors that occur in the parapharyngeal space. The parapharyngeal space is the underlying space from the base of the skull, down to the hyoid bone, with a deep location and complex anatomical relationships. There can be many benign and malignant tumors.

Parapharyngeal space tumor

Parapharyngeal space tumors refer to tumors that occur in the parapharyngeal space. The parapharyngeal space is the underlying space from the base of the skull, down to the hyoid bone, with a deep location and complex anatomical relationships. A variety of benign and malignant tumors can occur.

Western Medicine Name

Parapharyngeal space tumor

Affiliated Department

Department of Physiology-Stomatology

Disease site

Parapharyngeal space tumors have different symptoms and signs according to their location, tumor source, growth rate, invasion characteristics, and the age of the patient. Since the parapharyngeal space tumors are mostly benign tumors, they grow slowly and have potential, so there is no obvious early stage. Symptoms, with the development of the disease, the symptoms are mainly symptoms of neck masses and adjacent organ structures:

[1]. Painless neck masses or swellings are mostly painless masses found in the neck during inadvertent or physical examination.

[2]. The manifestation of organ involvement. Nasopharynx-Blocking the pharyngeal canal can cause tinnitus, hearing loss, and middle ear effusion, etc. Large lumps can cause nasal congestion and snoring; growth of the oropharynx can cause breathing Difficulty swallowing; changes in the output voice of the laryngo-pharynx and dyspnea. . The tumor grows into the pterygopalatine or is located between the ascending branch of the mandible and the transverse process of the cervical spine, which will cause the opening of the mouth to be restricted, or even the movement of the neck. . Nerve involvement involves tumors that originate from the nerve, and neuralgia such as neck pain, sore throat, or ear pain on one side; cervical sympathetic nerve involvement with specific Horner syndrome; ipsilateral vocal cord paralysis-hoarseness with vagus nerve involvement Inferior nerve involvement presents with ipsilateral tongue palsy; less common parapharyngeal involvement involves symptoms of neuroparalysis. Most scholars believe that the presence of neurological symptoms may indicate that the tumor is malignant <11.17.18>. Some patients have headaches due to compression of the internal carotid artery.

Due to the concealed anatomic location of the parapharyngeal space tumor and no specific symptoms, early diagnosis is difficult and often easy to be misdiagnosed as a common throat disease. Pang et al. Reported in a retrospective study that two parapharyngeal space tumors were misdiagnosed as tonsils. Peripheral abscesses and tonsils. However, as long as the attending doctor inquires about the medical history and physical examination in detail, especially the two-handed consultation to record the size and location of the mass, activity, texture and compressibility, and the application of speculum, a basic diagnosis can be made <4.17>. Necessary auxiliary examinations for suspicious masses, such as B-mode ultrasound, color Doppler ultrasound (good for vascular tumors), CT, MRI and angiography, and other imaging techniques and needle aspiration biopsy, especially 3D imaging technology in recent years The development of angiography can not only detect tumors early but also provide good knowledge about tumors and adjacent important neurovascular structures for surgery, so as not to cause unnecessary consequences and waste <8.3.20>.

[1]. Surgical treatment: At present, most scholars believe that surgical treatment is the main reliable treatment method for parapharyngeal space tumors, but due to the anatomy and pathological characteristics of parapharyngeal space tumors, domestic and foreign scholars have an approach to the hand. A lot of controversy.

. Preoperative preparations. Due to the deep anatomical position of the parapharyngeal space, the internal structure is complex, and many important nerve vessels around it. Therefore, preoperative imaging studies are very important. CT, MRI and angiography can determine the size of the tumor, The adjacency relationship between the site and the peripheral blood vessels and nerves is very important for the choice of surgical approach and the operation of the operation, which is helpful to guide the surgical treatment to avoid serious consequences and obtain better results.

(2). Choice of surgical approach Oral approach: According to the MayoClinic Center, almost half of the parapharyngeal space tumors were surgically removed before 1958. Most authors believe that this approach is because of its small surgical field and tumor. The relationship with the large vessels in the neck is unclear. Poor exposure when peeling off the tumor with blindness, easy to divide the tumor, easy to infect, easy to cause tumor cell planting, easy to accidentally damage the large blood vessels, causing severe bleeding and difficult to control, so The approach is only suitable for smaller tumor resections <4.18>; Through the neck with or without mandibular incision: Morfit first proposed the simultaneous removal of the mandibular gland through the submandibular incision in 1955.12 A case of parapharyngeal space tumor was later popularized by many authors. Pang <17> et al. Reviewed 18 years of surgical cases and most used this approach. This operation makes a horizontal incision of the hyoid bone, which can also be extended upward to the parotid gland. The mandibular gland is usually turned forward and back to protect the mandibular limb of the facial nerve. The fascia is cut to the submandibular space to facilitate the operation. Blunt separation of tumors. This approach can directly enter the parapharyngeal space, and can properly expose blood vessels and nerve structures, avoiding the risk of parotid gland resection and injury to the facial nerves. Because some authors believe that the approach has limited operating space, the trans-cervical approach is often associated with various approaches. This type of mandibular resection or even a partial mandibular resection is combined with vertical, segmented, or angled incisions of the mandibular body, angle, branch, or parajoint / joint area. In this way, the separation of the styloid hyoid bone and the styloid mandibular ligament during the operation can increase the exposure and reduce the damage of vascular nerves [21>. Application of the transcervical-parotid approach: This operation is to extend the neck incision up to the ear, perform a standard parotid resection, identify the main facial nerve, and then expose the lower part of the facial nerve. Then separate the abdominal muscles and expose the internal and external carotid arteries and jugular veins. And adjacent neural structures <19>. Hughes et al. <2> believe that this approach can be very well exposed and remove the tumor and the parotid gland in one piece while retaining the parotid gland, and first identify the facial nerve trunk to prevent trunk damage, and it can also be widely used in post-styloid tumors. However, Miller et al. <3> believe that in addition to deep parotid tumors that invade the parapharyngeal space, more choices of the transparotid approach should be avoided to reduce the risk of facial deformity and facial paralysis caused by the transcervical-mandibular center Dehiscence pathway: It can widely and clearly expose important vascular and nerve structures on the neck side, suitable for resection of small tumors confined to the upper part of the parapharyngeal space, or large vascular tumors that invade the upper part of the parapharyngeal space or skull base. In addition, the median dehiscence of the mandible also helps the exposure and resection of most malignant tumors in the space behind the styloid process and the hemangiomas surrounding the internal carotid artery at the carotid foramen; Transcranial base approach: the resection originates from the jugular foramen to Vasopharyngeal sheath tumors in the parapharyngeal space, that is, "C" -shaped prolonged incisions in the lateral cervical and posterior ears, fully expose the tumor at the lateral skull base, in the temporal bone and in the parapharyngeal space. This approach can also be applied to huge parapharyngeal space tumors that invade the skull base <4>. Maxillary external rotation approach: It is suitable for tumors located near the skull base in the upper part of the parapharyngeal space. The conventional Webber-Fergerson incision cuts the connection of the maxilla and reverses outward with the facial flap, which can expose the top of the nasopharynx. And the upper part of the parapharyngeal space is conducive to the removal of nasopharyngeal tumors that invade the parapharyngeal space. Preventive tracheotomy is feasible after surgery. (7) Expansion of wing points combined with mandibular incision: suitable for parapharyngeal space tumors invading the lateral skull base. (8) Other rare approaches: trans-parotid approach, trans-oral neck, trans-cervical-pharyngeal approach, trans-temporal fossa approach, etc. These approaches are mostly special approaches chosen by the author based on the characteristics of the tumor. As described by Bass, parotid approach is used to remove deep parotid tumors, especially dumbbell-shaped tumors <21>.

(3) Complications Complications of surgery are mainly caused by unfamiliarity with the anatomy of the site, improper preoperative evaluation, inaccurate patient selection, and improper application of the surgical approach. Generally speaking, postoperative complications of ganglion tumors, malignant tumors, and neurogenic tumors are common in parapharyngeal space tumors. The common complications are as follows: The cause of recurrence of parapharyngeal space tumors is mainly the tumor capsule. The rupture and tumor were not completely removed. The most common nerves involved in nerve injury are the facial nerve (especially through the cervical parotid gland and transparotid approach), , , , , and cervical sympathetic plexus. According to the degree, it can be divided into temporary and permanent damage. Corresponding neurological palsy symptoms. The most common vascular injury is carotid artery injury, and severe cases can die from hemorrhagic shock. Followed by the jugular vein, vertebral artery and external carotid artery. Complications of maxillary mandibular incision are common loss of teeth, improper or unconnected bones. Other complications such as incision pain, incision infection, cerebrospinal fluid leakage and airway obstruction, etc. <17.18>.

[2]. Non-surgical treatment: Due to the anatomical characteristics of the parapharyngeal space and the diversity of tumors in this area, the general malignant parapharyngeal space tumors that are invasively growing are not easy to be surgically removed. Radiotherapy, chemotherapy, interventional therapy and other comprehensive treatments can also be used as an adjunct to surgical treatment. Such as disseminated tumors of nasopharyngeal cancer, metastatic tumors from breast cancer, and highly malignant transactional neuromas in children, etc. <23>.

The parapharyngeal space is a potential space surrounded by the fascia on the outer side of the upper pharynx. As mentioned above, there are complex and important neurovascular structures inside, including the upper (skull base), posterior (cervical), and lateral ( Mandible), which limits the tumor's spread to the medial-nasopharyngeal and palatine tonsils and downward-to the parotid gland and the mandible. At the same time, it is not conducive to the surgical exposure of the site, that is, it is not conducive to the complete resection of the tumor. Therefore, the familiarity and emphasis on the anatomy of this part is the key to safe and effective surgical treatment of parapharyngeal space tumors <11.24>.

The pathological types of parapharyngeal space tumors are very wide, including primary tumors, direct dissemination of tumors in adjacent areas, and metastatic lesions. Most of them are benign tumors, which have slow growth and deep location, so early symptoms are not obvious and lack specificity. Sexual symptoms are bound to affect early diagnosis and treatment. For this reason, the application of impact technology in this field has been promoted, which has also become a research hotspot in this field. From the earliest X-ray photography and tomography to the current CT, high-resolution CT, MRI, angiography and three-dimensional imaging MRI and the like not only improve the early accurate diagnosis rate, but also can accurately identify the tumor location, size, adjacent neurovascular structure and even the nature of the tumor. Therefore, it provides important knowledge for the selection of the surgical approach for the operation of surgery <17.18.20.25>.

Although with the development of effective auxiliary examination techniques such as CT and MRI, the surgical approach to parapharyngeal space tumors is still a hot topic of debate among scholars at home and abroad. However, the choice of any surgical method must be based on the following three points: 1. the largest possible direct exposure of the tumor and complete resection of the tumor; 2. the largest possible protection of important neurovascular structures; 3. the largest possible non-occurrence or reduction Surgery complications. The surgeon should choose the appropriate surgical plan based on the above principles, as well as the characteristics of the specific patient and the tumor itself. According to domestic and foreign scholars, the transcervical approach and the corresponding expansion technique can basically achieve the resection of most tumors in the parapharyngeal space <2.3.4.17.18.21.23.26>.

In short, based on the anatomical, pathological, and pathological characteristics of parapharyngeal space tumors, clinicians should conduct detailed medical history inquiry and physical examination of suspicious patients and perform necessary auxiliary examinations such as CT, MRI, and angiography to achieve accurate early diagnosis And the development of active, effective and safe treatment options, especially the choice of surgical approach