Thalamic pain is a type of central neuropathic pain characterized by persistent, severe, and often disabling pain resulting from damage or dysfunction of the thalamus. Symptoms commonly include spontaneous burning or shooting pain, heightened sensitivity to pain (hyperalgesia), pain triggered by nonpainful stimuli (allodynia), and sensory abnormalities in the affected regions of the body corresponding to the involved thalamic nuclei.

This pathology was first described in 1906 by Joseph Jules Dejerine and Gustave Roussy in their work “Le syndrome thalamique” and was initially termed central post-stroke pain (CPSP) [6]. However, given that damage to other areas of the central nervous system can lead to similar clinical manifestations, the term CPSP is generally used to encompass all neuropathic pain syndromes following stroke, while “thalamic pain syndrome” specifically refers to the location of the lesion.

The involvement of the thalamus is documented in approximately half of patients with CPSP [3]. Although thalamic pain syndrome is closely associated with neurovascular pathology, any lesion affecting the thalamus can be a cause of the syndrome, which has a poor responsiveness to medication, including opioids [13,14]. In selected patients, surgical intervention is an effective approach for managing thalamic pain syndrome [9,18,22].

Nowadays, two surgical approaches are employed to eliminate persistent pain : deep brain stimulation (DBS) and stereotactic lesioning. Since the latter half of the 20th century, stereotactic cingulotomy has been utilized in the treatment of intractable pain. Anterior cingulotomy emerges as an effective neurosurgical intervention for treating thalamic pain with a minimal risk of adverse effects and preservation of cognitive and sensory functions [20,25]. Recent research using diffusion tensor imaging has delineated the cingulate cortex into five subregions : the subgenual, anterior cingulate cortex (ACC), midcingulate cortex (MCC), posterior cingulate cortex (PCC), and retrosplenial cortex (RSC). Findings suggest that the ACC, MCC, and RSC may play distinct roles in pain regulation [4,23,24]. The precise delineation between the anterior and midcingulate regions can vary slightly depending on the cytoarchitectonic criteria used. However, broadly speaking, area 24 spans both regions, with the anterior portions typically associated with the ACC and the posterior portions with the MCC [12,15]. This is why anterior cingulotomy involves lesioning both the ACC and the anterior part of the MCC. In cases involving non-ischemic thalamic lesions, there exists an opportunity to combine anterior cingulotomy with a stereotactic biopsy of the lesion in a single operation, facilitating histology and the planning of subsequent treatment.

A 45-year-old male presented with severe unilateral pain affecting the left limbs and the left side of the trunk for over 5 months. Three weeks preceding the onset of the pain syndrome, the patient reported experiencing paresthesia in the same areas of the body. The pain was described as burning, tingling, pins-and-needles, prickling, uncomfortable cold, and stabbing sensations.

Medication treatment involved a combination of non-steroidal anti-inflammatory drugs, corticosteroids, antidepressants, antiepileptic drugs (including carbamazepine, gabapentin, pregabalin), and opioids were not effective. The pain persisted chronically, steadily worsening in severity and significantly impacting the patient’s depression and quality of life. Pain severity was assessed using the PainDETECT questionnaire, while emotional status was evaluated using the Beck depression inventory (BDI) scale. Prior to surgery, the PainDETECT score was 33, and the BDI score was 42, indicating the presence of severe pain and depression. The pain worsened with movement. Furthermore, the patient experienced severe allergic dermatitis induced by the high doses of medications. A magnetic resonance imaging (MRI) scan revealed a lesion of unclear etiology in the right thalamus.

At the Romodanov neurosurgery institute, the patient underwent a combined surgical procedure involving stereotactic bilateral anterior cingulotomy and biopsy of the thalamic lesion. Operation was performed using a CRW Stereotactic frame (Radionics Inc., Burlington, MA, USA). Targets and trajectories were planned using ELEMENT software (Brainlab, Munich, Germany), following MRI-computed tomography fusion (shown in Fig. 1). Surgery was performed under general anesthesia with intravenous sedation.

Lesioning was conducted using a standard radiofrequency (RF) monopolar electrode (Cosman, Burlington, MA, USA) with a diameter of 2.1 mm and a 3.0 mm bar tip. The areas for cingulate lesioning were identified bilaterally through direct targeting. The initial target was located 1.5 mm above the lower border of the cingulate gyrus, 6.5 mm lateral to the midline, and 20.5 mm posterior to the tip of the frontal horn. This area includes the ACC and MCC portions of the cingulate gyrus, which correspond to cortical area 24. This area is known for its direct limbic and paralimbic connections, and its involvement in limbic-frontal-subcortical circuits, which are crucial for pain perception. The lesion was made at 75°C for 60 seconds, then electrode was withdrawn to 2 mm above the target, and an additional lesion was made at the same temperature and duration. Three lesions were simultaneously performed bilaterally in the anterior cingulate gyrus, followed by two lesions targeted 5 mm anterior to the previous ones (shown in Fig. 2).

Following the ablations, a stereotactic biopsy of the lesion in the right thalamus was immediately performed, revealing a diffuse astrocytoma World Health Organization grade II. Stereotactic radiosurgery for the glioma was conducted, using the LINAC “Trilogy + BrainLab,” employing intensity-modulated radiotherapy (IMRT) technology. The irradiated volume of the tumor was 1942 cubic millimeters, with a prescription dose of 13.5 Gray administered to 98.3% of the volume, and a maximum dose of 14.6 Gray.

The day following the cingulotomy, significant pain relief was noted, and a few days later, the pain syndrome was completely abolished. During the 2 years postoperative follow-up, the patient experienced total pain relief, with only mild and occasional paresthesia in the left limbs causing minor disturbance. Since discharge from the institute, the patient has not required any analgesic medication and reports improved mood, as evidenced by a decrease in BDI score from 42 to 12.

After 4 years post-operation, the patient experienced a recurrence of the pain syndrome, and MRI examination revealed tumor enlargement (shown in Figs. 3 and 4). Pain management is currently achieved through effective opioid therapy. The patient declined additional radiotherapy and has opted for chemotherapy. The patient’s BDI score is 20.

In recent years, DBS has become widely utilized not only for movement disorders but also in the treatment of some psychiatric disturbances, notably incredible chronic pain [1,3,5]. However, lesioning procedures continue to be a valuable tool in the treatment of aforementioned diseases due to their straightforward nature, high chance of achieving permanent therapeutic effect, short duration, and the cost-effectiveness of the operation. Additionally, ablative interventions do not require regular follow-up for programming, which becomes particularly relevant amidst the increased occurrences of climate catastrophes and military conflicts worldwide.

Since the middle of the 20th century, stereotactic cingulotomy has been effectively utilized in functional neurosurgery [7]. Anterior cingulotomy demonstrates its effectiveness in the treatment of obsessive-compulsive disorder, depression, chronic pain syndrome, and others [2,17]. Current research has identified the essential role of the cingulate cortex in pain, emotion, and memory [2,17]. The role of the ACC in pain regulation is well established, while the mechanisms of MCC and PCC contributions are not fully understood. According to recent studies, these regions play different roles in pain regulation [25,26]. The MCC regulates sensory hypersensitivity and receives pain-related information from the anteromedial thalamic nucleus. Additionally, the MCC facilitates pain-inhibitory activity of GABAergic neurons in the zona incerta through fiber connections between these structures [8]. Cingulotomy aims to reduce the pain by disrupting neural pathways involved in emotional processing, which contribute to the sensation of pain [21].

Our case demonstrates that combined operations in a single procedure - stereotactic RF lesioning of the dorsal ACC and stereotactic biopsy of the lesion in the thalamus allow us to achieve fast and permanent pain relief, verify the histology of the lesion, and apply appropriate nonsurgical treatment. The lesion in the thalamus has not enlarged in 2 years of follow-up; the patient does not experience any pain and does not require any analgesic medications, which allows for an increase in his quality of life. Meanwhile, the recurrence of pain over the 4 years of follow-up can be explained by tumor’s relapse and progression to malignancy.

To enhance the effectiveness of the operation, we recommend creating three bilateral lesions in the anterior area of the cingulate gyrus, including lesions in the ACC and the anterior portion of the MCC. Two mechanisms of pain relief can be proposed in this case. Firstly, modification of the emotional reaction to pain may occur due to changes in the limbic system after bilateral cingulotomy [21]. Secondly, there may be a slight reduction in tumor volume and its activity after radiosurgery, which can be additional factors in pain relief. In our case, no adverse effects were observed after stereotactic RF anterior cingulotomy, consistent with literature data indicating a low rate of complications [18,19]. Simultaneous stereotactic biopsy and cingulotomy allow for the identification of the etiology of the thalamic lesion and provide appropriate treatment for glioma. The introduction of modern ablative technologies, such as radiosurgery, MRI-guided focused ultrasound, laser interstitial thermal therapy, utilising high-field MRI, and modern planning software, allows for the improvement of the results of cingulotomy, minimization of adverse effects, and in some cases, renders the procedure non-invasive [10,11,16].

Simultaneous bilateral anterior cingulotomy and stereotactic biopsy of the thalamic lesion represent a safe intervention for thalamic pain syndrome, enabling the alleviation of pain, verification of the lesion’s etiology, and application of appropriate treatment. Stereotactic RF anterior cingulotomy is a relatively straightforward, short-duration, and cost-effective procedure with long-lasting positive effects.