Prolonged mechanical compression of optic nerve fibers caused by intracranial hypertension can result in irreversible vision damage and lead to blindness [1]. In general, patients with acute papilledema had better vision restored than patients with chronic, atrophic papilledema. The mechanism may be that the ICP lifting increases the pressure of the optic nerve tissues, inhibits the transport of axoplasmic flow, and finally results in the death of ganglion cells and axons [1]. The optic disc venous infarction secondary to intracranial hypertension may also play a role in visual function damage. Reducing ICP can save most cases of visual impairment before irreversible optic nerve ischemia occurs [3]. However, in certain cases, despite effective therapeutic management, axon loss might continue without any evidence of an atrophic optic nerve. Therefore, it is vital to identify the cause of intracranial hypertension, monitor and evaluate the changes in neuro-ophthalmic symptoms and signs, manage and control ICP, and avoid vision impairment as early as possible [1, 3].

For patients with continuous aggravation of symptoms and signs, neuroimaging and measurement of ICP should be performed as soon as possible to make an accurate diagnosis and appropriate management to save vision [1]. Treatment of intracranial hypertension is directed toward reducing ICP and preserving vision [7]. Carbonic anhydrase inhibitors (e.g., acetazolamide and topiramate) decrease ICP by reducing cerebrospinal fluid production [8]. In the acute setting, lumbar punctures and indomethacin administration are options. In patients with acute progressive vision loss, treatments with immediate effect, such as a CSF-diversion procedure, are considered the management [3]. Optic nerve sheath fenestration (ONSF) effectively improves severe papilledema and vision loss but is unhelpful for headaches as it cannot decrease ICP [9]. Venous stenting used to be an option for patients with venous sinus stenosis or obstruction who are not responding to medical therapy [3]. For patients with refractory IIH and concomitant venous sinus stenosis, venous stenting has become a safe and viable therapy option nowadays [10, 11]. In order to minimize complications of IIH related to venous stenting, surgeons are recommended to pay attention to the learning curve, hypercoagulable states, and obtaining internal carotid artery before and following stenting [10].

In our case, bilateral papilledema was caused by raised ICP related to right sigmoid sinus stenosis. Preoperative neuro-ophthalmic and neuroimaging examinations were normal. Symptoms and signs of intracranial hypertension appeared soon after the sigmoid sinus constriction surgery. Repeated MRV revealed a significant postoperative right sigmoid sinus stenosis (Fig. 3). These findings suggested that the patient presented with increased ICP associated with the surgery-induced right sigmoid sinus stenosis. Diuretic treatment could not relieve the symptoms and signs of intracranial hypertension. After discussing it with the neurologists, we considered solving postoperative sigmoid sinus stenosis the best choice [12]. With the development and popularization of neuroimaging, such as MRV and digital subtraction angiography (DSA), the venous sinus stenosis detection rate in patients with IIH is increasing [13, 14]. There is ongoing controversy about whether venous sinus stenosis is the cause or consequence of intracranial hypertension [4, 12, 15, 16]. Recent evidence suggests that restricted or collapsed dural sinuses frequently cause PT, which is frequently sustained by increased venous blood velocity-dependent flow turbulence [17]. Many of these instances harbor borderline opening pressures and lack papilledema. It is a pity whether the patient was IIH or SIH is unidentified due to the lack of lumbar puncture before the first surgery. Except for the right sigmoid sinus stenosis, the controlateral left sinus presented a smooth tapering narrowing, which reduces the sinus caliber to a thread-like flow (Fig. 3). The resulting overload of the dominant sinus was therefore crucial in this patient for the maintenance of an adequate venous drainage to prevent an excessive dural sinus pressure increase. There is evidence that bilateral dural sinus stenosis is a powerful risk factor for the development of raised ICP [18]. Rising dural sinus pressure leads to reduced CSF outflow rate via arachnoid villi and granulations with consequent CSF volume and pressure increase [19]. Nevertheless, there is no doubt that the sigmoid sinus constriction surgery must have impaired her cerebral venous drainage and worsened intracranial hypertension [4, 12, 20]. The marked improvement in symptoms and signs of intracranial hypertension after the second surgery confirmed our guess. Besides, the patient’s papilledema resolved entirely, and no recurrence was detected during the 3-year follow-up. Thus, the most likely cause of the onset of the cerebral hypertension condition with papilledema was dominant sinus surgical constriction by mechanical external compression, as confirmed by the complete clinical remission following the second operation to remove the implanted gelatin sponge. Therefore, we considered that the initial venous sinus constriction was an inappropriate therapeutic option for this patient with PT.

The most likely cause of PT for this patient was sinus stenosis. This causes blood acceleration in the stenosis with a turbulent motion during systole, resulting in the perception of a heartbeat. The first surgery’s clinical outcome supported this hypothesis. Because bilateral dural sinus stenosis would likely generate ICP, the first surgery was inappropriate and dangerous as there was stenosis on the left lateral sinus (Fig. 3). Indeed, this case highlights the relevance of adequate redundancy and stiffness of the dural sinus in CSF pressure homeostasis. It suggests that PT surgery by external sinus constriction is to be considered inappropriate. In fact, it implies the generation of a pressure gradient across the surgical stenosis, i.e., a condition currently considered the key factor for IIH pathogenesis. Even if surgical sinus constriction appears to alleviate PT, it achieves this by reducing flow turbulence, albeit at the expense of elevating sinus venous pressure further. Such pressure elevation is crucial in controlling ICP. Therefore, based on the current evidence available, this case report serves as an example of why surgical sinus constriction should no longer be considered a viable option for PT treatment.

To the best of our knowledge, this is the first report of increased ICP after sigmoid sinus constriction surgery. In summary, our case emphasized the importance of discovering the cause of papilledema and managing it appropriately in time. Despite the various and complicated causes of papilledema, thorough knowledge of the patient’s history and appropriate examination would be helpful in diagnosis. Ophthalmologists should strengthen cooperation with neurology, imaging, and other multidisciplinary departments to make early diagnoses and interventions to avoid severe vision impairment. Furthermore, this case also highlighted the importance of clarifying the etiology and selecting the appropriate therapeutic option for PT. Venous sinus constriction was an infeasible surgical option for PT.