Two cases of unexpected long-term improvement of Parkinson's disease after subthalamic nucleus deep brain stimulation removal.

Two patients with Parkinson's disease (PD) treated successfully with subthalamic nucleus deep brain stimulation (STN-DBS) for 3-4 years are reported, who demonstrated a persistent improvement following removal of STN-DBS for late infection. Possible hypotheses are discussed--whether a microlesioning effect or a disease-modifying effect of STN-DBS, though neither adequately explain this phenomenon.

Surgical pearls.

While endoscopic surgery is largely replacing microsurgery, many of the principles of trans-sphenoidal surgery are common to both techniques. For the novice surgeon there are many potential pitfalls that can, however, be avoided by attention to detail and careful planning. This article provides a practical overview from one surgeon's extensive experience.

Stereotactic neurosurgery for disabling tremor in multiple sclerosis: thalamotomy or deep brain stimulation?

Disabling tremor is common in multiple sclerosis and up to 75% of patients experience tremor at some point during their disease. The treatment of this tremor, however, remains challenging. Pharmacotherapy in general has been disappointing and stereotactic neurosurgery is becoming increasingly popular. However, the results of stereotactic treatments reported are variable and no systematic review has been performed. The aim of this study was to assess the role of thalamotomy and deep brain stimulation in the treatment of tremor in multiple sclerosis, and to compare the differences in efficacy and safety between the two techniques. We identified the relevant published studies and cases by searching the MEDLINE, EMBASS and the references lists of related articles, and performed a systematic review and assessment of the full texts of all articles selected. Initial tremor suppression was seen in 93.8% of patients who had thalamotomy and 96% in those who had deep brain stimulation. A total of 63.5% of patients had persistent tremor suppression at 12 months or more after thalamotomy. Twelve results for deep brain stimulation were not available in the reviewed literature. Functional improvement was seen only in 47.8% of those who underwent thalamotomy as opposed to 85.2% of those who had deep brain stimulation. While three of the four reported deaths were in patients who underwent thalamotomy, three of the four procedure-related haemorrhages followed DBS. Other common adverse effects like hemiparesis, dysarthria, swallowing difficulties, balance disorder, etc., was reported in both procedures. Numerous studies have attempted to assess the efficacy and safety of thalamotomy and DBS in the treatment of MS tremor, but no standardized outcome measures were used. Nonetheless, the data suggest that both thalamotomy and thalamic DBS are comparable procedures for tremor suppression and that adverse effects can occur with both procedures.

Use of the NeuroMate stereotactic robot in a frameless mode for functional neurosurgery.

BACKGROUND: The aim of this paper is to describe the use of the NeuroMate stereotactic robot for functional neurosurgery with a novel frameless ultrasound registration system. METHODS: A retrospective review of the evaluation and clinical use of the NeuroMate stereotactic robot in a frameless mode for functional neurosurgery. RESULTS: Prior to its clinical use a phantom study was undertaken to demonstrate an application accuracy of 1.29 mm. Subsequently the robot has been used in 153 functional neurosurgical procedures including 113 deep brain stimulator implantations. CONCLUSIONS: The NeuroMate stereotactic robot in a frameless mode has sufficient accuracy for a range of functional neurosurgical procedures, including movement disorder surgery.

Deep brain stimulation of the subthalamic nucleus: effectiveness in advanced Parkinson's disease patients previously reliant on apomorphine.

OBJECTIVES: To assess the efficacy of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with advanced Parkinson's disease previously reliant on apomorphine as their main antiparkinsonian medication. METHODS: Seven patients with motor fluctuations despite optimal medical treatment given as predominantly apomorphine infusion (n=6), or intermittent apomorphine injections (n=1) underwent bilateral STN DBS using frameless stereotactic surgery. Standard assessments of parkinsonism and motor fluctuations, using Unified Parkinson's Disease Rating Scale (UPDRS) were performed before and six months after surgery. Assessments were performed both on and off medication, and postoperative with the stimulators switched on and off. RESULTS: Bilateral STN DBS improved motor scores (UPDRS III) by 61% when off medication (p<0.05). Clinical fluctuations (UPDRS IV items 36-39) were reduced by 46.2% (p<0.05). Total daily apomorphine dose was reduced by 68.9% (p<0.05) and apomorphine infusion via a pump was no longer required in four patients. There were no operative complications. Two patients required treatment for hallucinations postoperatively but there was no significant change in mini-mental state examination. CONCLUSIONS: In patients with advanced Parkinson's disease, previously reliant on apomorphine, bilateral STN DBS is an effective treatment to reduce motor fluctuations and enable a reduction in apomorphine use.

Variability in position of the subthalamic nucleus targeted by magnetic resonance imaging and microelectrode recordings as compared to atlas co-ordinates.

BACKGROUND: Traditional methods for localisation of target nuclei for deep brain stimulation (DBS) have used brain atlas co-ordinates for initial targeting. It is now possible to visualise the subthalamic nucleus (STN) on magnetic resonance imaging (MRI) and determine the individual variability of its position. METHODS: The present study was performed in patients undergoing STN DBS for Parkinson's disease. The STN was directly targeted from axially obtained MRI and verified with microelectrode recordings. Postoperatively, the most effective contact was identified for each patient, and its position was calculated. RESULTS: Fifty electrodes were inserted in 25 patients. The target position varied considerably in relation to the mid-commissural point. The mean effective contact position lies just dorsal to the location of the STN in a standard brain atlas. CONCLUSION: The STN varies in position, and can be accurately targeted from MRI alone.

Use of the NeuroMate stereotactic robot in a frameless mode for movement disorder surgery.

BACKGROUND/AIMS: To evaluate the use of the NeuroMate stereotactic robot with a novel ultrasound registration system for movement disorder surgery (MDS). METHODS: Using the robot in a frameless mode, 51 patients underwent MDS. Surgical planning was carried out using MRI data obtained more than 24 h before surgery. RESULTS: 37 out of 50 targets in the subthalamic nucleus were satisfactorily identified with a single microelectrode trajectory and the final electrode positions were at a mean distance of 1.7 mm from the calculated target. There was a significant improvement in motor scores of the Unified Parkinson's Disease Rating Scale III (off medication) at 6 (43%) and 18 months (51.7%) compared to pre-operative scores (p < 0.05). CONCLUSIONS: The frameless robot using only MRI data can be used for MDS. The temporal separation of imaging from the surgical procedure provides additional time for detailed image analysis and planning.

Long-term outcome of spinal cord stimulation and hardware complications.

Spinal cord stimulation (SCS) is a treatment modality for medically intractable chronic pain. This study reports an 11-year experience with SCS assessing long-term pain relief and specifically evaluating complications and revisions. It took the form of a retrospective review of medical/surgical records with a postal questionnaire. The subjects were 102 patients with medically intractable chronic pain who underwent SCS implantation between 1989 and 2000. There were 64 revision operations carried out on 35 patients. These comprised electrode replacement/repositioning (29), generator replacement (23), cable failure (3) and implant removal (5). Five (4.9%) implants became infected and 2 required removal. Clinician-reported pain relief was substantial in 69 (68%) patients. This study adds to the weight of evidence that patients undergoing SCS derive significant benefits in terms of pain relief. However, revision rates remain high due to technical and biological factors.

Microvascular decompression for trigeminal neuralgia in patients with multiple sclerosis.

AIMS: To assess whether microvascular decompression (MVD) is a safe and efficacious treatment for patients with trigeminal neuralgia (TGN) and multiple sclerosis (MS). METHODS: Case records were reviewed of all patients with TGN and MS who underwent posterior fossa exploration with a view to MVD between 1993 and 2001. In all patients, magnetic resonance tomoangiography (MRTA) demonstrated vascular compression. RESULTS: Nine patients were included in the study. Seven patients underwent MVD alone; in 2 patients a partial sensory rhizotomy of the trigeminal nerve was added to the decompression. All patients had excellent initial pain relief. Recurrence of neuralgia was noted in 5 patients after MVD and in 1 of the 2 patients after partial sensory rhizotomy. Long-term pain relief was obtained in 1 patient who underwent a redo MVD after postoperative MRTA scans demonstrated recurrent vascular compression of the root entry zone (REZ). Thus only 4 out of 9 patients maintained pain relief. In addition, 3 patients experienced transient worsening of their MS. CONCLUSIONS: Although MVD provides good initial pain relief, the recurrence rate is much higher than that obtained in 'idiopathic' TGN. Although all procedures for the treatment of TGN are worse than those for idiopathic TGN, it is concluded that because of the high recurrence rate together with the morbidity associated with the procedure MVD should not be offered to patients with TGN and MS.

Team working: a report from the Society of British Neurological Surgeons.

Despite the obvious advantages of team-working these early pilot studies have provided an opportunity to see how difficult it is to formalize this concept in the current neurosurgical environment. The team approach and the patient database have often demonstrated the problems of patient management due to lack of resources, insufficient staff and pressure to deliver volume, rather than quality with inadequate levels of staff--precisely the criticism levelled at Bristol. If team working in neurosurgery is to succeed in developing quality standards for the continuity of patient care then the infrastructure has to be developed, support guaranteed and some aspects of culture within the service changed.

The role of somatostatin receptor scintigraphy in the management of pituitary tumours.

The detection of functioning neuroendocrine tissue bearing somatostatin receptors has been facilitated to a large extent by the availability of radiolabelled octreotide scanning with 111In octreotide. This review discusses the possible role for somatostatin receptor scintigraphy (SRS) in the evaluation of pituitary adenomas.