Facial deep zone pain is commonly associated with temporomandibular joint disorders, neuropathic pain and other diseases, but facial deep zone pain caused by cauda equina syndrome is of less concern and is easily misdiagnosed and missed in clinical practice. The authors adopted a surgical approach to treat 18 patients with cauda equina syndrome who showed pain in the deep facial area with satisfactory results, which are reported below. 1. Materials and methods 1.1 General data Eighteen patients with caudate syndrome presenting with facial deep zone pain who were hospitalized in our department from August 2005 to March 2010 were collected, including 5 males and 13 females, aged 21 to 65, with an average age of 45 years. The clinical data of the 18 patients are detailed in Table 1 Table 1 Clinical data of the patients Clinical characteristics Number of cases Proportion of clinical examination Soreness and swelling in the deep lateral facial area was significantly increased by pressure 12 67% Discomfort lymph nodes could be detected in the deep lateral facial area 6 33% No obvious local abnormality 2 11% History of external diagnosis Temporomandibular joint disorder disorder 10 56% Lymphadenitis 6 33% Atypical Trigeminal neuralgia 2 11% (Note: 2 patients had a combination of clinical features of significantly increased soreness and swelling on pressure in the deep facial area and accessible discomfort lymph nodes in the deep facial area) 1.2 Diagnostic criteria 1. Clinical symptoms of mainly pain and discomfort in the deep facial area, with no obvious local foci that induce pain in the deep facial area 2. The surgery was performed under general anesthesia. The tonsils were first removed by conventional methods. The tip of the stalk was touched inside the tonsil bed, then the surface pharyngeal constriction muscle was separated, the tip of the stalk was found, the attached stalk hyoid muscle was cut, the stalk was separated to the root with vascular forceps and septal sinus ring scrapers, and the root of the stalk was broken and removed with right-angle forceps (Figure 1); patients were routinely treated with postoperative anti-inflammatory support. Patients were discharged from the hospital with routine outpatient follow-up for 12 to 60 months. 1.4 Effect evaluation Efficacy assessment criteria Cured: the postoperative posterior deep zone pain symptoms completely disappeared; Improved: the postoperative posterior deep zone pain symptoms disappeared, but still sometimes attacked, the degree of significant reduction; Invalid: the postoperative posterior deep zone pain symptoms no change or no significant improvement. 2.Results After 18 patients received stem resection, they were followed up for more than 1 year. 14 cases (78%) had complete relief of pain symptoms in the lateral deep zone 1 week after surgery, 2 cases (11%) still felt distension and pain in the lateral deep zone 1 week after surgery, but it was significantly reduced compared with that before surgery, and the symptoms were basically relieved after 1 year of follow-up; 2 patients had no significant improvement of pain symptoms in the lateral deep zone after surgery; the total effective rate was 89% (16/18). 3, Discussion The deep facial lateral area is located at the lower edge of the zygomatic arch and external auditory canal, with the anterior edge of the occlusal muscle in front, the anterior edge of the sternocleidomastoid muscle, mastoid and diastasis muscle in the back, and the lower is bounded by the lower edge of the mandible [2]. The deep lateral facial region has the caudate, the caudate muscles, the internal jugular artery and the Ⅸ to Ⅻ pairs of cerebral nerves. Pain in the deep facial lateral region is a common disorder of the maxillofacial region, and common causes include temporomandibular joint disorder syndrome, local lymphadenitis, neuropathic pain, local tumors or inflammatory lesions [3]. However, pain in the deep lateral facial region due to stem overgrowth syndrome is often easily missed or even misdiagnosed by clinicians [1], and should be taken seriously by clinicians. The average history of our cases was about 1.5 years, and all of them had the experience of seeking long-term treatment in outside hospitals and misdiagnosis as other diseases and treatment, but often the treatment was not obvious or ineffective. The most commonly misdiagnosed disease in this study was temporomandibular joint disorder disorder syndrome. In our group, 10 cases (56%) were diagnosed as TMJ disorder disorder in outside hospitals, 6 cases (33%) were diagnosed as lymphadenitis, and 2 cases were diagnosed as atypical trigeminal neuralgia. Therefore, clinically, patients with deep facial zone pain without obvious foci or patients with deep facial zone pain that has been treated for other diseases without obvious effect should be aware of whether it is caused by stem syndrome. Stromal syndrome mostly presents with a long stromal process, and is therefore also known as stromal overgrowth syndrome, which was first reported by Eagle in 1937 and is also known as Eagle’s syndrome. The clinical manifestations of cauda equina syndrome are diverse [1]: the main symptoms are discomfort and pain in the throat, which may radiate to the ear, and a distinct foreign body sensation especially during swallowing; or reflex otalgia, head and neck pain, and increased salivation. In this group of cases, pain in the deep facial region is the main manifestation, and the mechanism may be the stimulation of the surrounding linguopharyngeal nerve, the mandibular branch of the trigeminal nerve, and the internal and external carotid arteries by the stem prominence, causing the related symptoms [1]. The etiology of the caudate syndrome remains unknown, and studies have found that the disease is closely related to congenital factors (genetic and embryonic development), acquired factors (neck surgery, trauma, abnormal calcium and phosphorus metabolism and rheumatic diseases), in addition to various factors such as long-term irritation leading to degenerative changes and psychological factors [4]. The diagnostic criteria are [1]: the presence of obvious clinical symptoms, palpation of the stalk in the fingers of the tonsillar fossa, confirmation of the stalk overgrowth by imaging, and disappearance of the symptoms by lidocaine infiltration of the tonsillar fossa anesthesia, two of which are met to diagnose the stalk syndrome. The main treatment method is surgical removal of the overgrown caudate, and there are two surgical routes, namely the intraoral route and the external cervical route. Although the external cervical approach has a clear surgical field, accurate search for the stalk and adequate amputation of the stalk, the surgery is traumatic and easily damages the facial nerve and leaves scars after surgery, which affects the aesthetics. The intraoral approach has the advantages of less surgical trauma, no scar on the neck, and less likely to damage the facial nerve, so it is more often used clinically; the disadvantage is that the surgical field is small and deep, which makes poor exposure of the caudate, and the root of the caudate cannot be approached as much as possible [5]. In this group of cases, the intraoral approach was adopted to remove the overgrown caudate, and satisfactory results were achieved. In conclusion, caudate syndrome is a cause of deep facial pain, which can be easily misdiagnosed and missed; if patients present with symptoms such as spontaneous pain and discomfort in the deep facial area, and signs such as soreness and swelling in the deep facial area are significantly aggravated by pressure, and if the diagnostic criteria of caudate syndrome are met, excision of the overgrown caudate can achieve better clinical results.