The infective symptoms of sigmoid sinus thrombophlebitis described in the current literature may not be typical [6]. In our cases, all the individuals exhibited ear leaks, however, only 5 of 9 also had headaches or fevers. There were 2 patients (Patients 2 and 3) with impaired consciousness, in contrast to the symptoms noted by Mete Iseri, Ireneusz, et al. [7,8,9]. All of our patients were primarily defined by ear symptoms, with minimal cranial nerve involvement. Optic papillary edema was only present in 1 patient with a combined brain abscess, which may be connected to the early use of antibiotics.

Various studies have supported the link between sigmoid sinus thrombophlebitis and various temporal bone complications [10]. All the patients had 1 to 2 temporal bone complications, and meningitis was the most frequent intracranial comorbidity. In contrast to individuals with combined brain abscesses, this group of patients frequently displayed varying fever and headache. The signs and symptoms of temporal bone complications might sometimes be subtle in an era where antibiotic use is common. Therefore, when treating patients with sigmoid sinus thrombophlebitis, otolaryngology experts must be vigilant in identifying other temporal bone problems.

For sigmoid sinus thrombophlebitis, the standard imaging method is the temporal bone CT. It displays the extent of the primary lesion in the middle ear as well as the level of bone erosion in the sigmoid sinus' anterior wall [10]. The anomalies of MRI's presentation have extremely high tissue resolution and sensitivity to blood flow and depend on when thrombosis occurs. T1-weighted images exhibit significant signals in the subacute phase (1–2 weeks) [11]. However, due to the progressive mechanization of the thrombus in patients with a duration of longer than two weeks, MRI frequently fails to demonstrate thrombosis. Only Patient 2's increased MRI raised the likelihood of sigmoid sinus and transverse sinus thrombosis in this group; the preoperative MRI results for the other patients did not raise any such concerns. Patient 5 is one example of a diagnosis that would have been missed if we simply used temporal bone CT and cranial MRI. The anterior wall of the sigmoid sinus did not appear to have any clear areas of bone degradation on the temporal bone CT scan, and neither did the scan on the MRI. However, the patient's preoperative MRV indicated that the sigmoid sinus was thin, and during surgery, the front wall of the sigmoid sinus had a bone defect of approximately 1 × 2 cm2. Additionally, this patient experienced typical sigmoid sinus thrombophlebitis symptoms such as headache, hyperthermia, and sepsis. Compared with conventional MRI, MRV can confirm cerebral venous sinus thrombosis and clarify the extent of thrombus, site of occurrence, and degree of stenosis. Additionally, recanalization of blood arteries following therapy can be seen by MRV, which can increase the accuracy of the diagnosis [1, 10, 11]. It is a crucial adjunct technique for detecting cerebral venous sinus thrombosis.

It is unclear how long sigmoid sinus thrombophlebitis patients will need to take antibiotics. Our cases had an average duration of antibiotic usage of 27 days, which included at least 1 week of home antibiotics, which is largely in line with the literature [12]. Due to the widespread usage of antibiotics, the bacterial culture positivity was only moderate. Although we grew 3 g-positive and 3 g-negative bacteria, most researchers [13] found that gram-negative bacteria were more prevalent. 2 of the 9 cases had mixed flora infections, which are frequently present in patients with sigmoid sinus thrombophlebitis. As a result, we frequently choose antibiotics that have a broad spectrum and are simple to cross the blood–brain barrier. The bacterial culture sensitivity test and clinical symptoms should be taken into account when determining the extent of antibiotic treatment.

Surgery is frequently the mainstay of treatment for otogenic sigmoid sinus thrombophlebitis. Depending on whether the sigmoid sinus is incised for embolization, it is classified as conservative or radical [14]. According to certain research, radical surgical operations such as jugular vein ligation or phlebotomy for thrombolysis should only be undertaken if infectious thromboembolic features are unmistakably progressing [15, 16]. Internal jugular vein ligation and incisions for thrombolysis were both shown to be ineffective in the treatment of individuals with sigmoid sinus thrombophlebitis, according to Thorsten et al.'s retrospective analysis of 6 patients with sigmoid sinus thrombophlebitis [17]. In our group, only otologic surgery was conducted on all 9 patients because there were no clear progressing indications of infective thrombus (Figs. 2 and 3). All 9 patients had a good prognosis and positive postoperative results. None of them showed infection or thrombus dislodging away from the organ. Therefore, we advise against performing invasive procedures such as lateral sinusotomy for thrombus removal or ligation in cases when there are no overt signs of an infective thrombus.

We think that modified mastoidectomy and tympanoplasty in stage I should be carried out as soon as possible in cases with sigmoid sinus thrombophlebitis secondary to middle ear cholesteatoma. The Trautmann method enables removal of the abnormal tissues from the middle ear and appropriate exposure of the surgical cavity. When the cholesteatoma epithelium and inflammatory granulation tissues were present in the damaged vein wall, only the outer membrane of the cholesteatoma was also removed. Using cartilage from the auricular nail cavity, type III tympanoplasty was performed in every patient in our group in stage I (Fig. 4c). Tympanoplasty staging is a subject of debate. When there are serious mucosal lesions, according to James et al. [18], tympanoplasty staging is necessary. According to Luca et al. [19], tympanoplasty in stage II has a recurrence incidence of up to 70%, however, opting for tympanoplasty in stage I nearly eliminates recurrence and lowers the need for hospitalizations and procedures. This approach is affordable and successful. Therefore, we think that tympanoplasty and modified mastoidectomy should be carried out as soon as possible. The key to treating this condition, particularly the sick tissue surrounding the eustachian tube aperture, is to completely remove the middle ear infective lesions. This is crucial for enhancing the hearing prognosis and aiding in restoring the middle ear's ability to hold air following tympanoplasty [20].

a The red arrow indicates the exposed facial nerve canal and the red star indicates the stapedial base. The granulation or cholesteatoma epithelium on the surface of the exposed facial nerve is removed without damaging the facial nerve sheath, and the granulation tissue that cannot be removed from the stapes base is cauterized with 10W bipolar cautery to prevent recurrence of cholesteatoma. b The red triangle indicates the exposed sigmoid sinus vein wall, and the cholesteatoma epithelium on the vein wall is removed, preserving the cholesteatoma basilar membrane. c The auditory chain is reconstructed through the cartilage piece of the ear cavity and a connection to the vestibular window is established

The role of anticoagulation therapy for sigmoid sinus thrombophlebitis is unclear. Six sigmoid sinus thrombophlebitis patients were included in the analysis by N. de Oliveira Penid et al. [21], 3 of whom received anticoagulation therapy and 3 of whom did not. 1 patient who was not taking anticoagulants and underwent follow-up testing experienced sigmoid sinus recanalization, indicating that the use of anticoagulants is not a factor in this condition. Anticoagulants have the risk of causing thrombocytopenia, worsening operating cavity bleeding, and encouraging the production of septic emboli. We did not administer anticoagulation, which is in keeping with many recommendations in the literature, because there were no evident signs of thrombosis in our case, the infection was swiftly under control following middle ear surgery, and the temperatures all quickly returned to normal range. In our opinion, anticoagulation should be performed only in those with persistent fever despite appropriate surgical intervention, extensive thrombus involvement or cerebral venous infarction, pulmonary embolism, or persistent sepsis [22], and the dosage and intensity of anticoagulation should be guided by a neurologist.