Robotic Guided Bilateral Anterior Cingulate Radiofrequency Ablation for Obsessive-Compulsive Disorder
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.302467
Source of Support: None, Conflict of Interest: None
Keywords: Anterior cingulate cortex, cognitive and behaviour therapy, frameless stereotaxy, o-arm, radiofrequency thermocoagulation, treatment refractory OCD
https://www.youtube.com/watch?v = oldkKG9YNkM
Obsessive compulsive disorder (OCD) is a chronic psychiatric illness with a lifetime prevalence of 0.6% in the Indian population compared to 2-3% in the western population. Pharmacotherapy along with cognitive behavioral therapy (CBT) is a highly effective first line of management in this group of patients., Approximately 40–60% of patients with OCD are refractory to this conventional treatment., These patients are suitable candidates for neurosurgical procedures like ablative or stimulation based neuromodulation.
Cingulotomy was initially used for the treatment of intractable pain following which, Whitty and colleagues performed Cingulotomy for the treatment of refractory OCD. The largest experience of cingulotomies is from the Massachusetts general hospital, Boston. This group has performed more than 1000 cingulotomies for various psychiatric illnesses. Bilateral anterior cingulotomies (BAC) is the most commonly performed surgery for the treatment of OCD.,,, Anterior capsulotomy and Sub-caudate tractotomy constitute the other ablative targets for refractory OCD. Deep brain stimulation (DBS) is the other modality, with a number of targets described, attaining equivalent results with an advantage of being a reversible procedure.,
The steady progress in precision neurosurgery owing to the innovations in the field of stereotactic neurosurgery paralleled with imaging techniques, has ensured the efficacy and safety of these procedures in the recent times. There is abundant literature on the performance of these procedures using frame-based stereotaxy. Here, we describe a novel technique of performing BAC using radiofrequency thermal ablation under robotic guidance with intraoperative O arm confirmation, for precise lesioning at the desired location.
A 23-year-old unmarried gentleman with higher secondary education status presented to the department of psychiatry with complaints of obsessions and compulsions for a duration of eight years. The illness was continuous with minor fluctuations and progressively affecting the patient both social and vocationally. The main symptoms were as follows: (i) intrusive thoughts that his hands became dirty after touching anything followed by a compulsive behavior to wash hands; (ii) thoughts if his hands were not washed properly then people could comment on the same; (iii) repetitive doubts if he was wearing clothes the correct way or inside out followed by compulsive changing of the clothes few times; (iv) doubts whether he has read a sentence completely followed by repeated reading multiple times; and (v) counting rituals. As a result of this, his academic performance suffered and dropped out of the school and also due to inefficient work, he was later removed from the job. Progressively worsening symptoms lead to a restricted lifestyle watching movies most the day, lying idle over the bed, minimal interaction with the family members. He took long time to complete simple tasks as a result of his repetitive actions and had depressed mood and mild anxiety symptoms.
Investigations including brain computerized tomographic (CT), magnetic resonance imaging (MRI) and electroencephalograms were normal. A neuropsychological assessment revealed an average IQ, normal performance on tests of frontal executive functioning, and mild psychomotor slowing possibly attributable to medication. His total score on the Yale–Brown Obsessive-Compulsive Scale (Y-BOCS) was 36.
Adequate trial of pharmacotherapy including augmentation agents, CBT and transcranial direct current stimulation all failed rendering the patient treatment-refractory and suitable for a neurosurgical procedure. Appropriate approval was obtained from the Psychosurgery Review Board, at our institution, constituted for approving neurosurgery for the psychiatric illness.
We present here the step by step technique of robotic guided BACs using radiofrequency thermo-ablation, in a patient with severe treatment-refractory OCD [Video 1].
Defining drug refractoriness
All the patients diagnosed with OCD should undergo comprehensive multidisciplinary team management. Drug refractory OCD is defined as:
Approval from the mental health review board should be sought before proceeding with the surgery.
We follow a standardized MRI protocol for robotic surgeries at our institution and is as follows:
Volumetric Computerized tomography (CT) is acquired which is merged with the MRI before registration and hence the CT is acquired in the same protocol as MRI to achieve perfect matching. This aids in superior registration and reduces the margin of error.
The planning of the trajectories for creating a lesion in the desired target is done a day prior to the day of surgery on the robotic software platform. We routinely plan four trajectories two on each side. The first target on each side is 2 cms posterior to the anterior most point of the frontal horn as seen in all the three planes of the MRI. A horizontal line of 2 cms length is drawn from this anterior most point another vertical perpendicular line is drawn so as to meet the cingulate gyrus 2-3 mm above the corpus callosum on the sagittal plane of the MRI. The intersection point at cingulate gyrus is marked and in the same plane another point marked 7 mm lateral to the midline represents the target. Another target 3 mm anterior to the first target is marked and trajectory created for both these targets using a pre-coronal entry point. The same process is repeated on the contralateral side.
The procedure was performed under general anesthesia, with the patient supine and head fixed with Mayfield clamp. We perform frameless laser-based skin registration using the robot (ROSA, Zimmer Biomet, Warsaw, Indiana, USA). Frame/Fudicial based registration is followed in most of the centers citing better accuracy. The literature shows similar accuracies with both the modalities. We have been using skin-based registration for performing lesioning of the hypothalamic hamartomas, heterotopias, focal cortical dysplasias and recently extended its use to perform hemispheric disconnection in patients suffering from drug-refractory epilepsy with precision and excellent results. The skin-based laser registration is robust with an error of less than 1 mm.
Following registration, the patient is prepped and draped and the robotic arm is driven to the predetermined trajectory. A hole is drilled through the skin using a 2.4 mm drill bit using hand-held pneumatic drill through the robotic arm adaptor with a 2.5 mm slot. The distance to the target is precalculated by the robotic software depending on the position of the robotic arm in relation to its distance from the patient's scalp. Once the distance to the target is obtained, it is marked on the radiofrequency probe. The probe has 4 mm uninsulated tip with a diameter of 2.2 mm and the desired length of the probe is inserted into the planned target. An O arm spin is performed before commencing the lesioning with the probe in-situ. The O arm CT once obtained is merged with preoperative MRI on the ROSA platform and the probe trajectory is matched with the preoperatively planned trajectory. On confirmation of the accuracy, the lesioning is performed with a temperature of 85° C set for 60 seconds, which produces a spherical lesion of approximately 5 mm diameter. Following the first lesion, the probe is withdrawn by 3 mm and another lesion is made, so as to create an overlapping lesion without any skip lesion. In a similar fashion eight lesions are created with 4 on each side to achieve complete lesioning of the anterior cingulate gyrus.
Video Link: https://youtu.be/oldkKG9YNkM
Video timeline with audio transcript:
0:00-0:09 This video Intends to demonstrate the technique of performing BAC in a case of severe treatment-refractory OCD.
0:10-0:20°CD is a common psychiatric condition characterized by intrusive thoughts about anything, rituals and compulsive behavior which are recurrent and uncontrollable leading to significant distress to the patient.
0:21-1:06 Briefly describing there are multiple circuits involved in the disease process. However, two well-known cortico–striato–pallido-thalamic loops are implicated in the genesis of OCD. A direct pathway which is excitatory to the cortex, acting as a positive feed-back, while the indirect pathway is inhibitory and forms the negative feed-back loop. The symptoms of OCD are related to the imbalance in the dopamine and serotonergic activity in the brain. It is postulated based on the imaging findings that hyperfunctioning of the dopaminergic activity in the orbitofrontal cortex and hypo-functioning of the serotonergic system in the basal ganglia to the disease causation.
1:07-1:40 History: A 23 years old gentleman presented with history of obsessions and compulsions over a 11-year period. He had intrusive thoughts of hands being dirty after touching anything with a compulsive behavior of washing his hands frequently. Thoughts of wearing clothes inside out accompanied with the compulsive behavior of frequent changing of clothes. He also had intrusive of thoughts reading incompletely leading to multiple reads and also multiple counting rituals. Due to these repetitive compulsive behavior, he was removed from the school and also could retain his job.
1:41-1:54 Examination revealed mild psychomotor slowing attributable to the poly pharmacotherapy. His YBOCS score was 36 categorizing the patient to extreme OCD.
1:55-2:35 Treatment: This patient was managed initially with multiple SSRIs followed by augmentation therapy over a period of 3–4 months without any benefit. He was subjected to two trials of CBT spanned over a period of six months which included the ERP therapy with only a transient improvement. Later on twenty sessions of tDCS were tried but with a limited success. Therefore a diagnosis of treatment-refractory OCD was made in view of failure of all the conservative treatment modalities. He was planned for BAC after obtaining the clearance from the institutional psychosurgery board.
2:36- 3:22 Planning: Before planning the surgery, MRI and CT brain are obtained under a specific protocol for all the cases undergoing robotic surgeries. The planning of the trajectories for creating a lesion in the desired target is done a day prior to the day of surgery on the robotic software platform. We routinely plan four trajectories two on each side. The first target on each side is 2 cms posterior to the tip of the frontal horn as seen in all the three planes of the MRI. The second trajectory on each side is planned approximately 3 mm anterior to the first target in the same plane. The trajectories are checked and planned meticulously so as to avoid transgressing any sulcus or the vessels on the way to the target.
3:23—3:41 Positioning: The patient is positioned supine with head fixed with a Mayfield clamp and attached to the robotic arm.
3:42-4:29: Registration: We routinely use six-point facial skin based laser registration. This is followed by the mesh registration covering the nose and the forehead, followed by zig-zag laser scanning of the forehead and then manually scanning bilateral scanning of both the temple regions. Once the registration is complete the accuracy check is done for all the six facial points and to correct any errors more than 1 mm by matching these points manually. If the error of >1 mm persists, reregistration is performed.
4:30-4.46: Entry Point: The robotic arm is driven to the desired trajectory and the entry point is marked as per the laser pointer.
4:47- 4:59: Drilling: A twist drill craniostomy of 2.5 mm diameter is performed using a pneumatic-powered handheld drill.
5:00-5:04: Dural coagulation: This is followed by dural coagulation using a monopolar coagulation.
5:05-5:26: The distance to target is noted as per the robotic console and the same is marked on the RF probe using a scale. We use a probe of 4 mm uninsulated active tip with a diameter of 2.2 mm for lesioning.
5:27-5:50: O arm and merging: After inserting the probe to the measured length and before proceeding to coagulation, an O arm spin is performed and the same is merged with the preoperative MRI images, to confirm the accuracy of the placement.
5:51-6:17 Lesioning at 85° C for 60 seconds is performed after confirming the position of the probe. The lesion size approximately corresponds to 5 mm diameter. The probe is withdrawn by 3 mm and another lesion is created in the same trajectory. Similar process is repeated with the rest of the trajectories creating a total of 8 burns.
6:18-6:35 Glue Injection: CSF leak after the withdrawal of the probe is prevented by plugging the dural rent by injecting the fibrin glue into the drill hole, thereby avoiding brain shift, which can lead to a significant decrease in the accuracy of the lesion if unchecked.
6:36-7:03 Follow-Up: Postoperative imaging show good spherical lesions involving bilateral cingulate gyri. Postoperative course was uneventful, patient is more cheerful than previously and has joined back to his work. His YBOCS score was 22 at 6 months and further reduced to 18 at one year follow-up compared to the preoperative score of 36 quantifying an overall 50% improvement.
The patient had an uneventful postoperative course with postoperative CT showing good lesioning at the intended target. The patients Y-BOCS score reduced to 22 at six months and 18 at one year follow-up. He has now joined back work, more cheerful than previously and patient himself reported subjective improvement of 60% compared to the preoperative status.
Pearls and pitfalls
Neurosurgical management of psychiatric disorders has seen many highs and lows over the last decade. In the recent times, precision and minimally invasive neurosurgery has gained momentum with immense advancements in the field of stereotactic neurosurgery. At our institution robotic guided surgeries are being performed extensively including Epilepsy and Functional neurosurgery, Deep brain biopsies, Pituitary surgeries. Given the vast experience, we extended its utility to psychiatric neurosurgery. In the case described above we could achieve >50% improvement in the patients symptoms by performing BAC. Anterior capsulotomy (AC), sub-caudate tractotomy, Limbic leucotomy and nucleus accumbens have all been utilized in the treatment of OCD with varying results. The evidence in the recent literature suggests, slightly better results with AC compared to BAC for OCD. Deep brain stimulation is the other modality used in the treatment of OCD with results comparable to the lesioning techniques.
Surgical treatment of severe refractory OCD should be actively perceived and encouraged, especially in tertiary care academic setups. Robotic guided psychiatric neurosurgery has not been explored yet as per the existing literature. Through this report, we intend to invoke the extension of the future robotic surgeries in the treatment psychiatric disorders.
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Conflicts of interest
There are no conflicts of interest.