Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders

BACKGROUND

For patients with psychiatric illnesses remaining refractory to 'standard' therapies, neurosurgical procedures may be considered. Guidelines for safe and ethical conduct of such procedures have previously and independently been proposed by various local and regional expert groups.

METHODS

To expand on these earlier documents, representative members of continental and international psychiatric and neurosurgical societies, joined efforts to further elaborate and adopt a pragmatic worldwide set of guidelines. These are intended to address a broad range of neuropsychiatric disorders, brain targets and neurosurgical techniques, taking into account cultural and social heterogeneities of healthcare environments.

FINDINGS

The proposed consensus document highlights that, while stereotactic ablative procedures such as cingulotomy and capsulotomy for depression and obsessive-compulsive disorder are considered 'established' in some countries, they still lack level I evidence. Further, it is noted that deep brain stimulation in any brain target hitherto tried, and for any psychiatric or behavioural disorder, still remains at an investigational stage. Researchers are encouraged to design randomised controlled trials, based on scientific and data-driven rationales for disease and brain target selection. Experienced multidisciplinary teams are a mandatory requirement for the safe and ethical conduct of any psychiatric neurosurgery, ensuring documented refractoriness of patients, proper consent procedures that respect patient's capacity and autonomy, multifaceted preoperative as well as postoperative long-term follow-up evaluation, and reporting of effects and side effects for all patients.

INTERPRETATION

This consensus document on ethical and scientific conduct of psychiatric surgery worldwide is designed to enhance patient safety.

Spontaneous closure of a dural arteriovenous fistula

Spontaneous closure of a dural arteriovenous fistula (dAVF) is a rare condition and only a few cases have been reported since its first description in 1976. We report delayed and progressive spontaneous closure of a dAVF after massive intracerebral hemorrhage documented by angiographic studies before and after bleeding. To our knowledge, this is the first report to document gradual closure of a dAVF by serial angiographic studies. The mechanism of spontaneous closure of dAVFs has not been fully elucidated. We suggest different factors for consideration from previously published data and show how each of these factors can influence the others.

What's new in surgical treatment for dystonia?

It is now established that pallidal deep brain stimulation (DBS) is effective in the treatment of generalized and segmental primary dystonia, although there is still insufficient evidence to support its benefit in focal and secondary dystonia. Because several studies have demonstrated that pallidal DBS improves quality of life (QoL), reduced QoL and disability that are nonresponsive to medical treatment are probably the main factors guiding the decision to consider surgery. Some studies have indicated that young patients with primary dystonia who have shorter disease duration and less severe dystonia are likely to have the best outcome from DBS. Therefore, surgery should not be delayed when disability and QoL are impaired to the extent that justifies the surgical risk. A case-by-case approach is recommended in patients who have secondary dystonia. The globus pallidus internus is considered the best target for dystonia. There are still not enough data about the effectiveness of thalamic, subthalamic nucleus, and premotor cortex stimulation. Targeting with multiple electrodes and intra-individual comparisons of outcomes may help determine which target would be more beneficial. With regard to the role of lesions, pallidotomy for dystonia is still performed in several countries and can play a role in selected patients. New technologies are already available to improve the stimulation programming for DBS patients and to increase battery longevity. In the near future, it is possible that we will be able to shape stimulation settings according to disease type and symptoms. © 2013 Movement Disorder Society.

Outcome of surgical decompression of spinal mass lesions in non-Hodgkin's lymphoma and plasmacytoma

OBJECTIVE

Surgical treatment for spinal mass lesions due to non-Hodgkin's lymphoma (NHL) or plasmacytoma is necessary only in rare instances. The purpose of this study was to investigate long-term outcome and quality of life of surgery combined with postoperative chemotherapy or radiochemotherapy.

METHODS

The data of patients, who underwent spinal surgery for mass lesions in a 10-year periods were reviewed, identifying 10 patients with a histopathological diagnosis of NHL or plasmacytoma. Functional outcome were assessed by the Karnofsky Performance Score (KPS), quality of life by the Short Form-36 (SF-36) Health Survey Questionnaire, and pain by the Visual Analog Scale (VAS).

RESULTS

Clinical presentations included pain (n=10), paresis (n=5), and sensory deficits (n=5). Surgical treatment included removal of the mass lesion (total, n=5; subtotal, n=5) for decompression, interbody fusion (n=3), and corporectomy followed by stabilization (n=1). Histopathological findings revealed NHL in five patients and plasmacytoma/multiple myeloma in five other patients. Postoperatively, all patients underwent chemotherapy or radiochemotherapy. Mean follow-up time was 38 months. At the last follow-up, 2 patients had succumbed to progression of disease. Pain intensity remained significantly reduced as compared to preoperatively (p=0.049). The KPS was 90-100% in five patients still alive, 70% in two, and 60% in one. SF-36 subscores were lower as compared to age-matched healthy controls.

CONCLUSIONS

This retrospective study shows that surgical decompression of spinal mass lesions is a valuable option in selected patients with NHL or plasmacytoma to improve neurological deficits and control pain. Long-term outcome after postoperative adjuvant therapy confirms prolonged stability of quality of life.

Hypomethylation of neuregulin in rats selectively bred for reduced sensorimotor gating

Low prepulse inhibition (PPI) of startle is associated with reduced sensorimotor gating found in schizophrenia. In rats with breeding-induced low PPI neuregulin (NRG1) methylation was significantly decreased in brain regions associated with this phenotype and with schizophrenia, i.e., the medial prefrontal cortex, the nucleus accumbens, and the ventral hippocampus, while methylation in the amygdala and dorsal hippocampus was less affected. The dopamine D2 receptor (DRD2) promoter region showed negligible changes between groups. Rats with low PPI may be used to understand the reduced epigenetic regulation found in schizophrenia, and eventually lead to the development of novel therapies.

Systemic treatment with 4-211Atphenylalanine enhances survival of rats with intracranial glioblastoma

OBJECTIVE

Increased amino acid transport in brain tumours is used for diagnostic purposes. It has been shown that the α-emitting radionuclide astatine-211 labeled to L-phenylalanine is taken up by glioblastoma cells. We here tested, if systemic treatment with 4-[211At]astatine-phenylalanine (At-Phe) has a beneficial effect on survival of rats with intracranial glioblastoma.

ANIMALS, METHODS

The rat glioblastoma cell line BT4Ca was implanted into the prefrontal cortex of female BDIX rats by stereotaxic microinjection (10,000 cells/3 µl; n = 83). 3 days after implantation At-Phe or phosphate buffered saline were injected intravenously. A third group was treated twice, i.e., on day 3 and 10. Health condition was assessed each day by using a score system. Rats were sacrificed on days 6, 10, 13 and 17 after implantation, or when showing premortal health condition to measure tumour volume and necrosis. The proliferation index (PI) was assessed after immunohistochemical staining of Ki-67.

RESULTS

Survival time of rats treated twice with At-Phe was significantly prolonged. Additionally, both At-Phe-treated groups remained significantly longer in a better health condition. Rats with poor health status had larger tumours than rats with fair health condition. Overall, irrespective of treatment the PI was reduced in rats with poor health condition. Necrosis was larger in rats treated twice with At-Phe.

CONCLUSION

Intravenous treatment with At-Phe enhanced survival time of rats with intracranial glioblastomas and improved health condition. These results encourage studies using local treatment of intracranial glioblastoma with At-Phe, either by repeated local injection or by intracavital application after tumour resection.

Transient global amnesia associated with accidental high-frequency stimulation of the right hippocampus in deep brain stimulation for segmental dystonia

We report on a 66-year-old woman with segmental dystonia treated with chronic bilateral deep brain stimulation of the globus pallidus internus, in whom accidental high-voltage, high-frequency stimulation induced an episode of transient global amnesia (TGA) via an electrode contact which was misplaced in the right hippocampus. A possible mechanism underlying this TGA episode may have been the inhibition of local neuronal activity or fiber activation by high current density via direct electrical stimulation of hippocampal structures. While a unifying etiology of TGA has not been proven so far, our case demonstrates a possible link between focal electrical stimulation of hippocampal structures and the full clinical picture of the syndrome.

Cervical myelopathy due to an epidural cervical mass after chronic cervical spinal cord stimulation

BACKGROUND

Spinal cord stimulation (SCS) is an established treatment for neuropathic pain. Severe long-term complications are rare. Only recently secondary mass lesions associated with chronic stimulation were noted to occur.

OBJECTIVES

To report the rare occurrence of cervical myelopathy secondary to an epidural cervical spinal mass after chronic cervical SCS.

METHODS

Implantation of a paddle electrode at C2-C4 for chronic neuropathic pain resulted in improvement of pain for several years but it lost its efficacy after 8 years. Myelography and postmyelographic CT detected an epidural mass surrounding the electrode and compressing the spinal cord when cervical myelopathy had developed 17 years after electrode implantation.

RESULTS

The mass which consisted of dense fibrous scar tissue was removed via hemilaminectomy. At postoperative follow-up at 8 months there was no further progression of gait disorder.

CONCLUSION

Long-term cervical SCS in a rare case may lead to fibrous epidural mass lesions which may not only cause loss of efficacy but which may also result in new neurological deficits.

Thalamic gamma oscillations correlate with reaction time in a Go/noGo task in patients with essential tremor

Intracerebral recordings of neuronal activity in patients undergoing deep brain stimulation have revealed characteristic movement-related desynchronization at frequencies <30 Hz and increased activity in the gamma band (~30-100 Hz) in the basal ganglia and thalamus. Thalamic gamma activity is also found during arousal. Here, we explore oscillatory gamma band activity recorded from the ventralis intermedius nucleus of the thalamus during motor performance in a Go/noGo task in 10 patients with essential tremor after implantation of deep brain stimulation electrodes. We show that movement-related gamma activity is lateralized to the nucleus contralateral to the moved side similar to previous findings in the globus pallidus internus and the subthalamic nucleus. The onset of contralateral gamma band synchronization following imperative Go cues is positively correlated with reaction time. Remarkably, baseline levels of gamma activity shortly before the Go cue correlated with the reaction times. Here, faster responses occurred in patients with higher levels of pre-cue gamma activity. Our findings support the role of gamma activity as a physiological prokinetic activity in the motor system. Moreover, we suggest that subtle fluctuations in pre-cue gamma band activity may have an impact on task performance and may index arousal-related states.

Involvement of human internal globus pallidus in the early modulation of cortical error-related activity

The detection and assessment of errors are a prerequisite to adapt behavior and improve future performance. Error monitoring is afforded by the interplay between cortical and subcortical neural systems. Ample evidence has pointed to a specific cortical error-related evoked potential, the error-related negativity (ERN), during the detection and evaluation of response errors. Recent models of reinforcement learning implicate the basal ganglia (BG) in early error detection following the learning of stimulus-response associations and in the modulation of the cortical ERN. To investigate the influence of the human BG motor output activity on the cortical ERN during response errors, we recorded local field potentials from the sensorimotor area of the internal globus pallidus and scalp electroencephalogram representing activity from the posterior medial frontal cortex in patients with idiopathic dystonia (hands not affected) during a flanker task. In error trials, a specific pallidal error-related potential arose 60 ms prior to the cortical ERN. The error-related changes in pallidal activity-characterized by theta oscillations-were predictive of the cortical error-related activity as assessed by Granger causality analysis. Our findings show an early modulation of error-related activity in the human pallidum, suggesting that pallidal output influences the cortex at an early stage of error detection.

Microsurgical clipping of previously coiled intracranial aneurysms

OBJECTIVE

Endovascular coiling techniques for the treatment of intracranial aneurysms have rapidly developed as an alternative option to surgical clipping. A distinct problem after endovascular coiling is the management of a residual aneurysm neck due to incomplete filling, compaction of coils or regrowth of the aneurysm. Treatment options in this situation include surgical clipping, re-coiling, stent implantation or observation.

METHODS

From June 2006 to August 2011, 15 patients underwent surgical clipping of residual or recurrent aneurysms after previous endovascular treatment. The mean age of the patients was 50.6 years (range, 27-85 years). The mean interval between coiling and clipping was 76.5 weeks (range, 0-288 weeks).

RESULTS

Thirteen patients revealed a regrowth of coiled aneurysms, and in 5 patients compaction of coils was present. Coil extrusion was observed in 9 patients intraoperatively. In case of coil obstruction at the aneurysmal neck during surgery, coils were partially or completely removed. In all cases complete occlusion of the aneurysms was surgically achieved.

CONCLUSION

Coiled aneuryms with incomplete occlusion, coil compaction or regrowth of the aneurysmal neck can be successfully treated with microsurgical clipping. Coil extrusion was more often observed intraoperatively than expected. Complete occlusion of the aneurysm can be performed safely, even if loops of coils protrude into the aneurysmal neck. In these cases intraoperative removal of the coils enables secure closure of the aneurysm with a surgical clip.

Akinetic mutism and parkinsonism due to subdural and intraventricular tension pneumocephalus

Pneumocephalus may occur after intracranial surgery and is most often asymptomatic. It is usually associated with posterior fossa surgery. Here, we present a 56-year-old man who developed akinetic mutism and parkinsonism caused by subdural and intraventricular tension pneumocephalus associated with decompression of a chronic subdural hygroma. As an emergency treatment, air was exchanged with saline via the drainage, which then was removed and a subduro-peritoneal shunt was implanted. The condition described here requires immediate attention and appropriate treatment.

Navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach to the jugular foramen without rerouting of the facial nerve

BACKGROUND

Jugular foramen tumors are rare and challenging lesions for skull base surgeons because of their difficult operative accessibility. Various surgical approaches to the jugular foramen have been described to overcome the morbidity of standard petrosectomy.

OBJECTIVE

To describe the surgical anatomy of a novel route to the jugular foramen without opening the fallopian canal, the navigated tailored presigmoidal suprabulbar infralabyrinthine approach.

METHODS

Ten cadaver heads were dissected under navigational guidance on both sides to examine the advantages and limitations of the presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal. Mastoidectomy was performed by using a high-speed drill. Under navigation guidance, the sigmoid sinus, jugular bulb, posterior semicircular canal, and fallopian canal were located and preserved. The jugular foramen with the extradural part of the IXth, Xth, and XIth nerve were identified.

RESULTS

Measurements of the surgical corridor and exposed petrous bone area on high-resolution computed tomography showed that the navigated presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal is a suitable route for extradural jugular foramen lesions with limited extension (approach height 5.59 ± 0.16 mm; approach width 7.68 ± 0.18 mm; approach surface 33.73 ± 1.37 mm; approach depth 32.92 ± 0.21 mm; vertical angle α of the surgical approach 41.3° ± 0.9°; horizontal angle β of the surgical approach 40.5° ± 0.6°).

CONCLUSION

The navigation-guided presigmoidal suprabulbar infralabyrinthine approach is a minimally invasive approach for selected lesions of the jugular foramen with preservation of the fallopian canal, labyrinthine block, and sigmoid sinus. This approach is suited for C1, De1, De2, Di1, and Di2 tumors according to the Fisch classification.

Changes of blood endocannabinoids during anaesthesia: a special case for fatty acid amide hydrolase inhibition by propofol?

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Available data from animal studies suggest that the narcotic drug propofol interacts with the endocannabinoid system. Inhibition of enzymatic degradation of anandamide could explain some of the characteristics of propofol. Direct measurements have not been reported yet in humans.

WHAT THIS STUDY ADDS

• Propofol does not change the time course of anandamide plasma concentrations during anaesthesia. Furthermore, propofol does not inhibit fatty acid amide hydrolase activity ex vivo or in vitro. Thus, specific characteristics of the narcotic drug propofol cannot be explained by peripheral inhibition of anandamide degradation in humans.

AIMS

The aim of our study was to describe the time course of endocannabinoids during different anaesthesia protocols in more detail, and to challenge the hypothesis that propofol acts as a FAAH inhibitor.

METHODS

Endocannabinoids were measured during the first hour of anaesthesia in 14 women and 14 men undergoing general anaesthesia with propofol and in 14 women and 14 men receiving thiopental/sevoflurane. We also incubated whole human blood samples ex vivo with propofol and the known FAAH inhibitor oloxa and determined FAAH enzyme kinetics.

RESULTS

Plasma anandamide decreased similarly with propofol and thiopental/sevoflurane anaesthesia, and reached a nadir after 10 min. Areas under the curve for anandamide (mean and 95% CI) were 53.3 (47.4, 59.2) nmol l(-1) 60 min with propofol and 48.5 (43.1, 53.8) nmol l(-1) 60 min with thiopental/sevoflurane (P= NS). Anandamide and propofol plasma concentrations were not correlated at any time point. Ex vivo FAAH activity was not inhibited by propofol. Enzyme kinetics (mean ± SD) of recombinant human FAAH were K(m) = 16.9 ± 8.8 µmol l(-1) and V(max) = 44.6 ± 15.8 nmol mg(-1) min(-1) FAAH without, and K(m) = 16.6 ± 4.0 µmol l(-1) and V(max) = 44.0 ± 7.6 nmol mg( 1 ) min(-1) FAAH with 50 µmol l(-1) propofol (P= NS for both).

CONCLUSIONS

Our findings challenge the idea that propofol anaesthesia and also propofol addiction are directly mediated by FAAH inhibition, but we cannot exclude other indirect actions on cannabinoid receptors.

Electromagnetic-guided neuronavigation for safe placement of intraventricular catheters in pediatric neurosurgery

OBJECT

Ventricular catheter shunt malfunction is the most common reason for shunt revision. Optimal ventricular catheter placement can be exceedingly difficult in patients with small ventricles or abnormal ventricular anatomy. Particularly in children and in premature infants with small head size, satisfactory positioning of the ventricular catheter can be a challenge. Navigation with electromagnetic tracking technology is an attractive and innovative therapeutic option. In this study, the authors demonstrate the advantages of using this technology for shunt placement in children.

METHODS

Twenty-six children ranging in age from 4 days to 14 years (mean 3.8 years) with hydrocephalus and difficult ventricular anatomy or slit ventricles underwent electromagnetic-guided neuronavigated intraventricular catheter placement in a total of 29 procedures.

RESULTS

The single-coil technology allows one to use flexible instruments, in this case the ventricular catheter stylet, to be tracked at the tip. Head movement during the operative procedure is possible without loss of navigation precision. The intraoperative catheter placement documented by screenshots correlated exactly with the position on the postoperative CT scan. There was no need for repeated ventricular punctures. There were no operative complications. Postoperatively, all children had accurate shunt placement. The overall shunt failure rate in our group was 15%, including 3 shunt infections (after 1 month, 5 months, and 10 months) requiring operative revision and 1 distal shunt failure. There were no proximal shunt malfunctions during follow-up (mean 23.5 months).

CONCLUSIONS

The electromagnetic-guided neuronavigation system enables safe and optimal catheter placement, especially in children and premature infants, alleviating the need for repeated cannulation attempts for ventricular puncture. In contrast to stereotactic techniques and conventional neuronavigation, there is no need for sharp head fixation using a Mayfield clamp. This technique may present the possibility of reducing proximal shunt failure rates and costs for hydrocephalus treatment in this age cohort.

Cyclooxygenase-2 supports tumor proliferation in vestibular schwannomas

BACKGROUND

Recent studies have shown that cyclooxygenase-2 (COX-2) plays an important role in tumor growth and neovascularization. However, COX-2 expression in vestibular schwannomas (VSs) has not been investigated.

OBJECTIVE

To analyze the pattern of COX-2 expression in sporadic and neurofibromatosis type 2 (NF2)-associated VSs and its relationship with tumor proliferation and microvessel density.

METHODS

Fifteen sporadic and 15 NF2-associated VSs were examined for COX-2 expression, microvessel density, and proliferation rate by immunohistochemical methods. Immunohistochemical scores were used to interpret the extent and intensity of COX-2 staining. Microvessel density (MVD) was determined using von Willebrand factor (vWf). Proliferation rate was quantified using Ki-67. The relationship among COX-2 expression, MVD, and proliferation rate was statistically analyzed.

RESULTS

COX-2 expression was detected in 29 (96.67%) of 30 VSs, with no significant difference between sporadic and NF2-associated VSs (P = .722). In 6 (20%) VSs, COX-2 expression was graded as strong, in 12 (40%) as moderate, and in 11 (36.7%) as weak. VSs with high proliferation showed significantly higher COX-2 expression (P = .015) than VSs with low proliferation. COX-2 expression and MVD did not show specific biological correlations (P = .035).

CONCLUSION

Our data demonstrate that COX-2 is expressed in VSs. High COX-2 expression in VSs with high proliferation rates suggests that the COX-2 pathway may be involved in the development and growth of VSs.