OCD surgery in India is reserved for patients with the most severe cases of the disease, when pharmacological and psychotherapeutic alternatives have been exhausted. Although estimates in the literature vary, there is a relative consensus that a significant minority of OCD patients, from as low as 10% and up to 40%, are treatment refractory. Some of these patients, who remain severely ill, are eligible for surgical intervention, given appropriate inclusion criteria and availability of required psychiatric and surgical expertise.
Egazmoniz, a neurologist from Lisbon along with Alemida Lima performed the first prefrontal leucotomy. He was later on awarded a Nobel prize for his work in 1949. Walter Freeman a neuorpsychiatrist from US along with his surgical colleague James Watts performed frontal transection – later on came to be known as the famous “Ice Pick” surgery. It is another story that Watts later on severed ties with Freeman following his inadvertent use of this surgery. By 1954, more than 20 thousand surgeries were performed in US and similarly more than 10 thousand in UK. Ironically, it was a surgeon, Henri Laborit from Paris, who helped end the “golden age” of psychosurgery and usher in the pharamacologic age of psychiatry by noting the tremendous benefit Chlorproamzine offered in improving psychiatric disorders.
The modern era of precision psychosurgery was brought in with invention of stereotactic equipment by Spiegel and Wycis. The lesions became smaller and more precise, thus avoiding several side effects with larger lesions of prestereotactic era. During the last five decades, psychosurgery continued to be practiced at select centres. The four different targets currently being used are anterior capsule (AC), CG, Subcaudatetractotomy and Limbic leucotomy. (Fig. 1) Nucleus accumbens is another promising target for this surgery. AC and CG are the most popular and rewarding targets for OCD and hence will be discussed in detail. Two methods of surgery are employed for altering these targets. One involves performing lesion and the other involves stimulation of these targets using deep brain stimulation (DBS). In a lesion a radiofrequency unit is used to produce (destroy) a thermal lesion of calculated volume. This is permanent and irreversible. DBS has been in use for now over four decades for pain and movement disorders. Recently US FDA approved the use of DBS for OCD. Both this procedures are performed using stereotactic techniques which offer a high degree of accuracy (within 1-2mm).
Cingulotomy : Laitinen showed that electric stimulation of the anterior cingulum and subcaudate region altered autonomic responses and anxiety levels in psychiatric patients. PET studies have provided further evidence about the role of CG. In a small series of patients with chronic anxiety disorders and severe phobias, activation PET studies performed as the patients were presented with stimuli to recreate their fears demonstrated consistently increased regional cerebral blood flow in the ACC, OFC, left thalamus, and right CN. Rauch et al reported atrophy of the caudate body in subjects who had undergone one or more cingulotomies approximately six months before the MRI studies. Clinical observations suggest that OCD patients do not improve immediately after psychosurgery but that several weeks to months are required for positive clinical effects to manifest.
Cingulotomy is carried out under mild sedation and local anaesthesia. MRI is used for defining target coordinates. Anterior CG is the preferred target site. Radiofrequency ablation is used to produce lesion. The resultant lesion involves 2.-2.5 cm of entire thickness of anterior CG
Anterior Capsulotomy/Stimulation : Capsulotomy was first described by Talairach in 1949 and popularized by Lars Leksell in Sweden. The goal of anterior capsulotomy is to interrupt frontothalamicconnections at the point where they converge in the anterior limb of the internal capsule, between the head of the caudate and putamen Anatomical studies confirm that the anterior limb of the internal capsule contains the anterior thalamic radiations (connecting the frontal lobes with the medial and anterior thalamic nuclei) and the prefrontal corticopontine tract. Fiber connections between OFC and striatum also cross through internal capsule. Besides this internal capsule is surrounded by other important anatomical area like bed nucleus of striaterminalis, nucleus accumbens, ventral striatum which all form the part of the ventral striatopallidal complex. Interruption or modulation of these target sites forms the basis of OCD surgery. The advantage of DBS is that it can reversibly recruit neighbouring structures to improve the benefits of surgery without causing unwanted side effects. In 1999, Nutin et al demonstrated that electrical stimulation of the anterior limbs of the internal capsules induced beneficial effects in a patient with treatment-resistant OCD during the first minutes after the initiation of stimulation. The target is the junction of the anterior capsule and the ventral striatum, within 1–2mm of the posterior border of the anterior commissure.
Other target sites : Subcaudatetractotomy, Limbic leucotomy and Gamma knife capsulotomy are the other surgical options practiced by few groups. However, as their results are more or less similar and are less commonly practiced they will not be discussed. Of interest to note is that one group reported 89% success rate following limbic leucotomy with higher complication rates. This may be due to more extensive lesions involved in limbic leucotomy (it is a combination of anterior cingulotomy and subcaudatetractotomy). Interested readers can refer to the references mentioned.
Patient selection: The multicentre DBS trial was the most recent and systematic approach towards the surgical treatment of OCD. Four centres recruited 26 patients over eight year period. These criteria have been accepted by the “National Advisory Committee for Psychosurgery in India” which held its first meeting on 8th March, 2009; for considering surgical interventions in OCD. OCD diagnosis and severity: Detailed patient screening, record review, interviews with treating clinicians and baseline assessments, including the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th edition, should be used to assure that OCD is the primary diagnosis (the disorder judged by clinicians and patients as imposing the greatest burdens of symptom and functional impairment). OCD has to be of at least 5 year’s duration. YBOCS symptom intensity in the ‘severe’ range was required (score of28 or more). OCD should be judged to cause marked functional impairment with a Global assessment of Functioning (GAF) score of 45 or less.
Treatment resistance : This is defined as adequate trial (≥ 3 months) with maximally tolerated doses of at least three serotonin reuptake inhibitors (SRIs), one of which has to be clomipramine. Trials combining an SRI with additional medications (including a neuroleptic and a benzodiazepine) should also be tried. All patients were required to have had behavior therapy, defined as a minimum of 20 sessions of therapist-guided exposure and response prevention. Patients who attempt behavioral therapy but who demonstrate marked intolerance to it (in the therapist’s judgment) are eligible.
Exclusion criteria : Patients are excluded if there is a history of a current or past psychotic disorder, a manic episode within the preceding 3 years, any current clinically significant neurological disorder or medical illness (except for tic disorders) or any clinically significant abnormality on preoperative MRI, any labeled DBS contraindication and/or inability to undergo pre-surgical MRI, history of substance abuse or dependence or a clinical history of severe personality disorder.
Independent review: At each center desirous of performing OCD surgery a committee including psychiatrists not connected with the surgery, neurologist and neurosurgeon should review the clinical histories, baseline evaluations and the consent process.
Other rating scores : Hamilton Rating Scale for Depression (HAM-D), Beck Depression inventory (BDI) and Hamilton Rating Scale for Anxiety (HAM-A) should also be performed.
Results : In a retrospective report of 198 patients undergoing cingulotomy for various psychiatric disorders, Ballantine noted upto 70% improvement in patients with OCD. There is generally a delay of 3-6 months in the onset of beneficial effect after cingulotomy. The results are better with larger or repeat lesions. Minor symptoms of headache, low-grade fever, and nausea are common after cingulotomy but generally last less than 24-48 hours. Transient unsteady gait, dizziness, confusion, urinary retention, and isolated seizure can occur; although mild and self limiting, these symptoms may last up to several weeks. Permanent significant behavioral or cognitive decline has not been reported after cingulotomy. In a review of stereotactic cingulotomy, Cosgrove and Rauch25 described OCD treatment experience of one major centre. In 800 cingulotomies performed over a 40-year period at Massachusetts General Hospital, there were no deaths and only two infections reported.
Leksell reported that 50% of OCD patients responded to capsulotomy. In another study, Bingley found that 25 out of 35 patients (78%) were either symptom-free or much improved an average of 35 months after thermocapsulotomy.Mindus and Jenike retrospectively reviewed all cases of capsulotomyreported by the early 1990s. They judged that 64% of 213 patients for whom adequate information was available could be considered responders.
In the multicentre DBS for OCD trial the mean preoperative YBOCS was 34± 0.5. The postoperative improvement was gradual, similar to that observed in lesional surgeries. At three months there were 50% responders which improved to 61.5% at the last follow up and if one considers the last group of patients (who were implanted electrodes at the new target site, i.e. the posterior part of anterior limb of IC), the improvement was seen in more than 75% patients. The GAF increased from an average of 34 to 59. At last followup, work, school or homemaking functioning was described as fair or good in 21 of the 25 patients. Capacity for independent living was considered fair or good in 20 of 25 patients. There was also significant improvement in the co-morbid anxiety and depression. The improvement in depression and anxiety is observed earlier than the improvement in OCD symptoms. As discussed earlier DBS involves titration of optimal parameters for symptom control. During this period there is an immediate improvement in mood and anxiety providing a clue to selecting the right contact point and stimulation parameters.
DBS is associated with a slightly higher incidence of complications; that include haemorrhage, infection and hardware failures. In the above multicentre study there were two incidence of haemorrhage (not significant) and one incidence of hardware complications. Patients reported worsening of symptoms when their stimulators were switched off, this improved upon restarting the stimulators.
Conclusion : In 1997 the Journal of Clinical Psychiatry published a supplement in the Expert Consensus Guidelines Series entitled ‘Treatment of obsessive-compulsive disorder The guideline states ‘In the adult with extremely severe and unremitting OCD, neurosurgical treatment to interrupt specific brain circuits that are malfunctioning can be very helpful’. However, it seems that surgical therapy for intractacble OCD may be underused. It is 12 years since this guidelines and today we are at a very fortunate period where our understanding of OCD has improved and so has the surgical therapy. The modern neurosurgical practice, including DBS, has made surgical interventions less risky. The reversibility and titrability which DBS provides would help the fence sitters also to take a surgical decision. Surgery, however, is not the end of the disease story. It would need preoperative and postoperative active participation from the psychiatrists to manage these patients, as the responsibility and commitment towards the patient care would increase following surgery.